Page 1 of 17

IMPLEMENTATION OF AN INTERNAL EGR TECHNOLOGY IN A MDD

ENGINE TOWARDS MEETING MAR-I USING NUMERICAL SIMULATIONS

Ricardo Ferreira Gasparini1 Flaacutevio Augusto Levoto Cintra12 Mario Trevizan13

Graf Gernot2

MWM Motores Diesel1 AVL List GmbH2

E-mails ricardogasparininavistarcombr flaviocintranavistarcombr mariotrevizannavistarcombr gernotgrafavlcom

ABSTRACT

A great part of the projects in the engine design field are today facing new challenges in the basic engine design and calibration area Most of the efforts have been driven by new emissions level regulations which have become more and more demanding Although the use of Exhaust Gas Recirculation (EGR) is nowadays often used for automotive Diesel engines to achieve NOx levels complying stringent legislations requirements such as MAR-I electronically controlled external EGR systems still presents an expensive technology often unsuitable for small Diesel engines for off-road applications An interesting and cost effective solution towards meeting those new emission requirements for smaller Diesel engines is the so-called internal EGR which is obtained by modifying the valve train system Among some few possibilities found in the market one can add an extra intake valve lift event during the exhaust stroke in order to increase the level of exhaust residuals in the cylinder That increased amount of gases with reduced concentration of O2 and increased concentration of CO2 contributes mainly to reduce the in-cylinder average temperature which then reduces the NOx formation rates That allows advancing of the start of combustion in order to reach very competitive fuel consumption It has been researched and applied the internal EGR technology so that a sufficient amount of exhaust gases is able to flow back to intake manifold and finally fill the cylinder together with upcoming cooled air charge of the subsequent stroke This technology is also known as AVL TINERreg system which stands for

Technology for In-cylinder Nitrogen oxides Emission Reduction This paper describes the extensive use of numerical simulation to successfully apply this technology and also investigate possible drawbacks and propose system pre-designs predicting their performance in advance prior to prototyping phase Each of the sub-systems which require modifications demands specific types of numerical approach The inlet valve changes have been studied via 1D engine flow simulation with GT-POWER with respect to the resultant level of extra residual gas fraction in different engine operating points Then the target valve lift is studied via cam lobe modifications and valve lift dynamics using a multi-body numerical simulation approach via AVL EXCITE code The mechanical fuel injection system is characterized via hydraulics simulation using AVL HYDSIM code allowing the definition of the layout for a new fuel injection system hardware The injection system has been tested on a system rig to validate the simulations prior to the engine tests Individual

Page 2 of 17

parts prototyping phase and their individual performance of the new components has been validated on the light of the specs provided by the simulations The final engine dyno results proved the technical solution and showed reduction of 3 in BSFC and 29 in terms of fuel rate complying with MAR-I NOx emission levels INTRODUCTION

Since the beginning of 2015 new Diesel engines for non road mobile machinery in the power range of 37 560 kW have to comply with MAR-I (similar to Stage IIIA) legislation that is the first emission legislation for off highway applications which includes Construction and Agricultural machines Based on market investigations this kind of applications use to apply mechanical injection system up to 75kW and electronic injection system above that power to achieve such level of emissions It is known that mechanical systems present a lower cost complexity and better field maintenance than electronic systems and considering that no emission regulation were in place until 2015 a mechanical injection system was the solution for almost all low-range and mid-range applications When it comes to MAR-I and take into account the market experience above 75kW must go with electronic injection system solution and here is a great opportunity in the development of MAR-I engine portfolio a mechanical engine with the maximum power possible Despite the internal EGR solution is to improve NOx levels this paper describes the application of this solution to achieve higher power rates without compromise the new emission legislation 1 METHODS AND APPROACHES

11 Regulatory

PROCONVE MAR-I emission legislation for Construction and Agricultural Machinery have specific emissions levels according to the power range (similar to Stage IIIA) see table 1

Power (kW)

CO (gkWh)

HC+NOx (gkWh)

MP (gkWh)

130 le P le 560 35 40 02

75 le P lt 130 50 40 03

37 le P lt 75 50 47 04

19 le P lt 37 55 75 06

Table 1 MAR-I Emissions Levels

Page 3 of 17

The timing to introduce PROCONVE MAR-I legislation is divided by power rating and the type of machine starting January 2015 and completing on January 2019

12 Strategy

For the reason already explained the technology path in the market is to apply mechanical engine below 75kW and to develop a solution where a mechanical injection system above 75kW works could be a market spread reducing the total owner cost

The application of exhaust gas re-circulation (EGR) to diesel engines for NOx control can be used to meet MAR-I emission standards Internal EGR is a very cost-effective technology for in-cylinder nitrogen oxides emission reduction and presents some advantages compared to external EGR solution

No external pipes (use to be expensive) No EGR control system Low sensitiveness to exhaust backpressure Low sensitiveness to fuel sulfur content No additional maintenance Cost and packaging advantages Excellent cold start and warm-up characteristics

The scope of this work is to apply the internal EGR technology (AVL TINERreg solution) in a known mechanical engine that already meets MAR-I but with 100hp power rate limit

13 Working Principle

The AVL TINERreg internal EGR working principle is basic a pre-lift of the intake vale where the exhaust and intake valves open during the exhaust stroke Hence a certain amount of exhaust gas is delivered towards the intake ports and re-aspirated together with fresh air during the next intake stroke event as see in figure 1

Figure 1 Internal EGR working principle

Page 4 of 17

14 Approaches

Each of the sub-systems which require modifications demands specific types of numerical approach The inlet valve changes have been studied via 1D engine flow simulation with GT-POWER with respect to the resultant level of extra residual gas fraction in different engine operating points The model is calibrated with air intake combustion and valvetrain systems which include all pipes of inlet and exhaust systems turbocharger and camshaft design The GT-Power also gives a combustion hardware matrix to be evaluated and implemented with new cam profile

The mechanical fuel injection system is characterized via hydraulics simulation using AVL HYDSIM code allowing the definition of the layout for new fuel injection system hardware The model is calibrated with the injection pump characteristics which include injection pump modeling pump cam design and fuel pipes The injection system has been tested on a system rig to validate the simulations prior to the engine tests Then the target valve lift is studied via cam lobe modifications and valve lift dynamics using a multi-body numerical simulation approach via AVL EXCITE code The model is calibrated with valve train lay out and external loads After the simulation work a hardware matrix is defined in order to run the experiments to select the best hardware Individual parts prototyping phase and their individual performance of the new components have to be validated on the light of the specs provided by the simulations

System Injection Combustion Valve train

Simulation Hydraulics 1D Engine Multi-body dynamics

Input data Injection pump modeling pump cam

injection pipes Injection Nozzle

AIS head (ports) exhaust

turbocharger valve lift design engine friction Injection pump hydraulics

Valve train design loads

Tool AVL HYDSIM GT-POWER AVL EXCITE Output data Injection pump

hydraulics characteristics nozzle flows

Combustion bowl nozzle matrix swirl levels turbocharger

and valve lift

Valve lift design

Table 2 Simulation approach

Page 5 of 17

2 MODELING AND SIMULATION

21 Engine configuration

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was cachieve MAR-I without further effort

Table 3 Main engine data

22 Combustion System

The thermodynamic cycle simulations were carried out with the GTprogram GT-Power simulates the thermodynamic processes in the engineof one dimensional gas dynamics in the intake and exhaust system The program version used was v730 The GT-Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measuremevalve lift curves port flow coefficients combustion characteristics and engine friction were also derived from the current engine A base line was conduct to calibrate the model

AND SIMULATION

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was c

without further effort

The thermodynamic cycle simulations were carried out with the GT-Power engine simulation Power simulates the thermodynamic processes in the engine under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measurement data Required input data for the simulation li

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was capable to

Power engine simulation under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine nt data Required input data for the simulation like

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

Page 6 of 17

Figure 1 Port flow coefficients

Figure 2 Valve lift curves (intake and exhaust)

After a base line concluded and the GT-Power model is calibrated the internal EGR system (AVL TINERreg) was implemented following the working principle already explained Base on the calibrated simulation model a layout of TINERreg intake cams was conducted The predicted engine performance was calculated under consideration of the current hardware The contracted values for intake and exhaust pressure losses as well as charge air cooler performance and pressure losses were adjusted to the calibrated baseline engine model The figure 3 shows the engine heat release used as input in the GT-Power model

Page 7 of 17

Figure 3 Rate of heat release of the current engine

The figure 4 shows the GT-Power model implemented

Figure 4 GT-Power Simulation Model

Page 8 of 17

23 Valve train

The valve train simulation was carried on by AVL Excite software to analyze the valve train system of the new cam profile Kinematic and dynamic analysis loads valve clearance and tolerance study of tappet spherical contact area were the main objectives of the analysis The input data is the valve train design which includes design and material of all components of the system the loads and the valve lift proposals The figure 5 shows the model implemented on the AVL Excite environment

Figure 5 Excite timing drive model for single valve train (SVT)

24 Simulation results

The output of the simulation was a test matrix showing the recommended the hardware to achieve the target The test matrix was feed by three main simulations as follows

Fuel injection system Combustion lay out Valve lift profile

241 Fuel injection system

The hydraulic simulation of the injection system carried out by AVL HYDSIM varied all the features related to the injection pump nozzle and fuel pipes such as nozzle flow cam velocity of the pump line inner diameter and etc

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 3 of 17

The timing to introduce PROCONVE MAR-I legislation is divided by power rating and the type of machine starting January 2015 and completing on January 2019

12 Strategy

For the reason already explained the technology path in the market is to apply mechanical engine below 75kW and to develop a solution where a mechanical injection system above 75kW works could be a market spread reducing the total owner cost

The application of exhaust gas re-circulation (EGR) to diesel engines for NOx control can be used to meet MAR-I emission standards Internal EGR is a very cost-effective technology for in-cylinder nitrogen oxides emission reduction and presents some advantages compared to external EGR solution

No external pipes (use to be expensive) No EGR control system Low sensitiveness to exhaust backpressure Low sensitiveness to fuel sulfur content No additional maintenance Cost and packaging advantages Excellent cold start and warm-up characteristics

The scope of this work is to apply the internal EGR technology (AVL TINERreg solution) in a known mechanical engine that already meets MAR-I but with 100hp power rate limit

13 Working Principle

The AVL TINERreg internal EGR working principle is basic a pre-lift of the intake vale where the exhaust and intake valves open during the exhaust stroke Hence a certain amount of exhaust gas is delivered towards the intake ports and re-aspirated together with fresh air during the next intake stroke event as see in figure 1

Figure 1 Internal EGR working principle

Page 4 of 17

14 Approaches

Each of the sub-systems which require modifications demands specific types of numerical approach The inlet valve changes have been studied via 1D engine flow simulation with GT-POWER with respect to the resultant level of extra residual gas fraction in different engine operating points The model is calibrated with air intake combustion and valvetrain systems which include all pipes of inlet and exhaust systems turbocharger and camshaft design The GT-Power also gives a combustion hardware matrix to be evaluated and implemented with new cam profile

The mechanical fuel injection system is characterized via hydraulics simulation using AVL HYDSIM code allowing the definition of the layout for new fuel injection system hardware The model is calibrated with the injection pump characteristics which include injection pump modeling pump cam design and fuel pipes The injection system has been tested on a system rig to validate the simulations prior to the engine tests Then the target valve lift is studied via cam lobe modifications and valve lift dynamics using a multi-body numerical simulation approach via AVL EXCITE code The model is calibrated with valve train lay out and external loads After the simulation work a hardware matrix is defined in order to run the experiments to select the best hardware Individual parts prototyping phase and their individual performance of the new components have to be validated on the light of the specs provided by the simulations

System Injection Combustion Valve train

Simulation Hydraulics 1D Engine Multi-body dynamics

Input data Injection pump modeling pump cam

injection pipes Injection Nozzle

AIS head (ports) exhaust

turbocharger valve lift design engine friction Injection pump hydraulics

Valve train design loads

Tool AVL HYDSIM GT-POWER AVL EXCITE Output data Injection pump

hydraulics characteristics nozzle flows

Combustion bowl nozzle matrix swirl levels turbocharger

and valve lift

Valve lift design

Table 2 Simulation approach

Page 5 of 17

2 MODELING AND SIMULATION

21 Engine configuration

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was cachieve MAR-I without further effort

Table 3 Main engine data

22 Combustion System

The thermodynamic cycle simulations were carried out with the GTprogram GT-Power simulates the thermodynamic processes in the engineof one dimensional gas dynamics in the intake and exhaust system The program version used was v730 The GT-Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measuremevalve lift curves port flow coefficients combustion characteristics and engine friction were also derived from the current engine A base line was conduct to calibrate the model

AND SIMULATION

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was c

without further effort

The thermodynamic cycle simulations were carried out with the GT-Power engine simulation Power simulates the thermodynamic processes in the engine under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measurement data Required input data for the simulation li

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was capable to

Power engine simulation under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine nt data Required input data for the simulation like

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

Page 6 of 17

Figure 1 Port flow coefficients

Figure 2 Valve lift curves (intake and exhaust)

After a base line concluded and the GT-Power model is calibrated the internal EGR system (AVL TINERreg) was implemented following the working principle already explained Base on the calibrated simulation model a layout of TINERreg intake cams was conducted The predicted engine performance was calculated under consideration of the current hardware The contracted values for intake and exhaust pressure losses as well as charge air cooler performance and pressure losses were adjusted to the calibrated baseline engine model The figure 3 shows the engine heat release used as input in the GT-Power model

Page 7 of 17

Figure 3 Rate of heat release of the current engine

The figure 4 shows the GT-Power model implemented

Figure 4 GT-Power Simulation Model

Page 8 of 17

23 Valve train

The valve train simulation was carried on by AVL Excite software to analyze the valve train system of the new cam profile Kinematic and dynamic analysis loads valve clearance and tolerance study of tappet spherical contact area were the main objectives of the analysis The input data is the valve train design which includes design and material of all components of the system the loads and the valve lift proposals The figure 5 shows the model implemented on the AVL Excite environment

Figure 5 Excite timing drive model for single valve train (SVT)

24 Simulation results

The output of the simulation was a test matrix showing the recommended the hardware to achieve the target The test matrix was feed by three main simulations as follows

Fuel injection system Combustion lay out Valve lift profile

241 Fuel injection system

The hydraulic simulation of the injection system carried out by AVL HYDSIM varied all the features related to the injection pump nozzle and fuel pipes such as nozzle flow cam velocity of the pump line inner diameter and etc

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 4 of 17

14 Approaches

Each of the sub-systems which require modifications demands specific types of numerical approach The inlet valve changes have been studied via 1D engine flow simulation with GT-POWER with respect to the resultant level of extra residual gas fraction in different engine operating points The model is calibrated with air intake combustion and valvetrain systems which include all pipes of inlet and exhaust systems turbocharger and camshaft design The GT-Power also gives a combustion hardware matrix to be evaluated and implemented with new cam profile

The mechanical fuel injection system is characterized via hydraulics simulation using AVL HYDSIM code allowing the definition of the layout for new fuel injection system hardware The model is calibrated with the injection pump characteristics which include injection pump modeling pump cam design and fuel pipes The injection system has been tested on a system rig to validate the simulations prior to the engine tests Then the target valve lift is studied via cam lobe modifications and valve lift dynamics using a multi-body numerical simulation approach via AVL EXCITE code The model is calibrated with valve train lay out and external loads After the simulation work a hardware matrix is defined in order to run the experiments to select the best hardware Individual parts prototyping phase and their individual performance of the new components have to be validated on the light of the specs provided by the simulations

System Injection Combustion Valve train

Simulation Hydraulics 1D Engine Multi-body dynamics

Input data Injection pump modeling pump cam

injection pipes Injection Nozzle

AIS head (ports) exhaust

turbocharger valve lift design engine friction Injection pump hydraulics

Valve train design loads

Tool AVL HYDSIM GT-POWER AVL EXCITE Output data Injection pump

hydraulics characteristics nozzle flows

Combustion bowl nozzle matrix swirl levels turbocharger

and valve lift

Valve lift design

Table 2 Simulation approach

Page 5 of 17

2 MODELING AND SIMULATION

21 Engine configuration

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was cachieve MAR-I without further effort

Table 3 Main engine data

22 Combustion System

The thermodynamic cycle simulations were carried out with the GTprogram GT-Power simulates the thermodynamic processes in the engineof one dimensional gas dynamics in the intake and exhaust system The program version used was v730 The GT-Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measuremevalve lift curves port flow coefficients combustion characteristics and engine friction were also derived from the current engine A base line was conduct to calibrate the model

AND SIMULATION

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was c

without further effort

The thermodynamic cycle simulations were carried out with the GT-Power engine simulation Power simulates the thermodynamic processes in the engine under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measurement data Required input data for the simulation li

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was capable to

Power engine simulation under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine nt data Required input data for the simulation like

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

Page 6 of 17

Figure 1 Port flow coefficients

Figure 2 Valve lift curves (intake and exhaust)

After a base line concluded and the GT-Power model is calibrated the internal EGR system (AVL TINERreg) was implemented following the working principle already explained Base on the calibrated simulation model a layout of TINERreg intake cams was conducted The predicted engine performance was calculated under consideration of the current hardware The contracted values for intake and exhaust pressure losses as well as charge air cooler performance and pressure losses were adjusted to the calibrated baseline engine model The figure 3 shows the engine heat release used as input in the GT-Power model

Page 7 of 17

Figure 3 Rate of heat release of the current engine

The figure 4 shows the GT-Power model implemented

Figure 4 GT-Power Simulation Model

Page 8 of 17

23 Valve train

The valve train simulation was carried on by AVL Excite software to analyze the valve train system of the new cam profile Kinematic and dynamic analysis loads valve clearance and tolerance study of tappet spherical contact area were the main objectives of the analysis The input data is the valve train design which includes design and material of all components of the system the loads and the valve lift proposals The figure 5 shows the model implemented on the AVL Excite environment

Figure 5 Excite timing drive model for single valve train (SVT)

24 Simulation results

The output of the simulation was a test matrix showing the recommended the hardware to achieve the target The test matrix was feed by three main simulations as follows

Fuel injection system Combustion lay out Valve lift profile

241 Fuel injection system

The hydraulic simulation of the injection system carried out by AVL HYDSIM varied all the features related to the injection pump nozzle and fuel pipes such as nozzle flow cam velocity of the pump line inner diameter and etc

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 5 of 17

2 MODELING AND SIMULATION

21 Engine configuration

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was cachieve MAR-I without further effort

Table 3 Main engine data

22 Combustion System

The thermodynamic cycle simulations were carried out with the GTprogram GT-Power simulates the thermodynamic processes in the engineof one dimensional gas dynamics in the intake and exhaust system The program version used was v730 The GT-Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measuremevalve lift curves port flow coefficients combustion characteristics and engine friction were also derived from the current engine A base line was conduct to calibrate the model

AND SIMULATION

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was c

without further effort

The thermodynamic cycle simulations were carried out with the GT-Power engine simulation Power simulates the thermodynamic processes in the engine under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine and was calibrated to full lead measurement data Required input data for the simulation li

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

The engine chosen for this work is a 4 cylinder engine with 43L of displacement and 2 valve head design this engine was applied for truck and bus application and already meets PROCONVE P5 (Euro III) legislation Considering that the engine hardware was capable to

Power engine simulation under consideration

of one dimensional gas dynamics in the intake and exhaust system The program version used

Power simulation model was set up according to geometry data of the current engine nt data Required input data for the simulation like

coefficients combustion characteristics and engine friction were engine A base line was conduct to calibrate the model

Page 6 of 17

Figure 1 Port flow coefficients

Figure 2 Valve lift curves (intake and exhaust)

After a base line concluded and the GT-Power model is calibrated the internal EGR system (AVL TINERreg) was implemented following the working principle already explained Base on the calibrated simulation model a layout of TINERreg intake cams was conducted The predicted engine performance was calculated under consideration of the current hardware The contracted values for intake and exhaust pressure losses as well as charge air cooler performance and pressure losses were adjusted to the calibrated baseline engine model The figure 3 shows the engine heat release used as input in the GT-Power model

Page 7 of 17

Figure 3 Rate of heat release of the current engine

The figure 4 shows the GT-Power model implemented

Figure 4 GT-Power Simulation Model

Page 8 of 17

23 Valve train

The valve train simulation was carried on by AVL Excite software to analyze the valve train system of the new cam profile Kinematic and dynamic analysis loads valve clearance and tolerance study of tappet spherical contact area were the main objectives of the analysis The input data is the valve train design which includes design and material of all components of the system the loads and the valve lift proposals The figure 5 shows the model implemented on the AVL Excite environment

Figure 5 Excite timing drive model for single valve train (SVT)

24 Simulation results

The output of the simulation was a test matrix showing the recommended the hardware to achieve the target The test matrix was feed by three main simulations as follows

Fuel injection system Combustion lay out Valve lift profile

241 Fuel injection system

The hydraulic simulation of the injection system carried out by AVL HYDSIM varied all the features related to the injection pump nozzle and fuel pipes such as nozzle flow cam velocity of the pump line inner diameter and etc

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 6 of 17

Figure 1 Port flow coefficients

Figure 2 Valve lift curves (intake and exhaust)

After a base line concluded and the GT-Power model is calibrated the internal EGR system (AVL TINERreg) was implemented following the working principle already explained Base on the calibrated simulation model a layout of TINERreg intake cams was conducted The predicted engine performance was calculated under consideration of the current hardware The contracted values for intake and exhaust pressure losses as well as charge air cooler performance and pressure losses were adjusted to the calibrated baseline engine model The figure 3 shows the engine heat release used as input in the GT-Power model

Page 7 of 17

Figure 3 Rate of heat release of the current engine

The figure 4 shows the GT-Power model implemented

Figure 4 GT-Power Simulation Model

Page 8 of 17

23 Valve train

The valve train simulation was carried on by AVL Excite software to analyze the valve train system of the new cam profile Kinematic and dynamic analysis loads valve clearance and tolerance study of tappet spherical contact area were the main objectives of the analysis The input data is the valve train design which includes design and material of all components of the system the loads and the valve lift proposals The figure 5 shows the model implemented on the AVL Excite environment

Figure 5 Excite timing drive model for single valve train (SVT)

24 Simulation results

The output of the simulation was a test matrix showing the recommended the hardware to achieve the target The test matrix was feed by three main simulations as follows

Fuel injection system Combustion lay out Valve lift profile

241 Fuel injection system

The hydraulic simulation of the injection system carried out by AVL HYDSIM varied all the features related to the injection pump nozzle and fuel pipes such as nozzle flow cam velocity of the pump line inner diameter and etc

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 7 of 17

Figure 3 Rate of heat release of the current engine

The figure 4 shows the GT-Power model implemented

Figure 4 GT-Power Simulation Model

Page 8 of 17

23 Valve train

The valve train simulation was carried on by AVL Excite software to analyze the valve train system of the new cam profile Kinematic and dynamic analysis loads valve clearance and tolerance study of tappet spherical contact area were the main objectives of the analysis The input data is the valve train design which includes design and material of all components of the system the loads and the valve lift proposals The figure 5 shows the model implemented on the AVL Excite environment

Figure 5 Excite timing drive model for single valve train (SVT)

24 Simulation results

The output of the simulation was a test matrix showing the recommended the hardware to achieve the target The test matrix was feed by three main simulations as follows

Fuel injection system Combustion lay out Valve lift profile

241 Fuel injection system

The hydraulic simulation of the injection system carried out by AVL HYDSIM varied all the features related to the injection pump nozzle and fuel pipes such as nozzle flow cam velocity of the pump line inner diameter and etc

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 8 of 17

23 Valve train

The valve train simulation was carried on by AVL Excite software to analyze the valve train system of the new cam profile Kinematic and dynamic analysis loads valve clearance and tolerance study of tappet spherical contact area were the main objectives of the analysis The input data is the valve train design which includes design and material of all components of the system the loads and the valve lift proposals The figure 5 shows the model implemented on the AVL Excite environment

Figure 5 Excite timing drive model for single valve train (SVT)

24 Simulation results

The output of the simulation was a test matrix showing the recommended the hardware to achieve the target The test matrix was feed by three main simulations as follows

Fuel injection system Combustion lay out Valve lift profile

241 Fuel injection system

The hydraulic simulation of the injection system carried out by AVL HYDSIM varied all the features related to the injection pump nozzle and fuel pipes such as nozzle flow cam velocity of the pump line inner diameter and etc

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 9 of 17

Figure 6 Injection pump (source Robert Bosch Mechanical VE Pump Catalogue

2010) and the AVL HYDSIM Model

The result of simulation presented a small modification on the injection pump side with increased cam velocity combined with a little higher line inner diameter A nozzle flow matrix was created to be tested as could be seen on the table 3

Table 3 Nozzle matrix

A recommendation of nozzle configuration was done in order to optimize the test bed phase

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 10 of 17

242 Combustion lay out

In the following the required combustion system layout including recommended test variants for test bed development work are defined This includes

Injector Nozzle Matrix Combustion bowl sketches Target swirl levels

The nozzle flows were defined according to fuel injection system simulations But the combustion simulation shows an indication of priorities for different nozzle variants as shown in the figure 7

Figure 7 Prioritization of Nozzle Matrix

The current piston bowl has been reviewed and is also considered as variant to be tested but for AVL experience a piston bowl with soot-in-oil (SiO) rim should bring better combustion behavior and benefits especially when consider the late injection timings required to comply with emission legislation requirements For test bed phase this recommended bowl was considered as priority The target swirl level was recommended to be tested only to verify how sensitive the internal EGR technology is to the swirl levels Three variants of swirl levels are defined to be verified in the test bed the nominal of the current engine 15 higher and 15 lower The combustion system layout summary recommended two combustion bowl variants a nozzle flow prioritization which has 9 sets to be tested but one set as start point and three swirl level variants The performance target can be achieved with current turbocharger configuration but for test bed purpose a 10 smaller turbine is recommended as variant

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 11 of 17

243 Valve lift profile

The new valve lift for the internal EGR event was design considering the opening and closing valve ramps of the main events due to current valve train configuration Considering these constraints the internal EGR events was studied and base on that four variants are designed to be verified on the thermodynamic simulation The figure 8 shows the valve lifts of the main events and a Tinerreg cam lift event proposal

Figure 8 Intake valve opening during exhaust event

Based on the main valve lift for internal EGR event another variant was designed in order to be tested These variants considered different timing or different duration or maximum lift as shown in the figure 9

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 12 of 17

Figure 9 Valve lift variants for internal EGR events

Figure 10 Engine performance with AVL Tinerreg cam variants

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 13 of 17

The figure 10 presented the expected fuel consumption (BSFC) for the two variants of Tinerreg

cam (7 and 11)

Figure 11 Residual gas content

The impact of Tinerreg cam design in the residual gas content (or EGR rate) can be observed

in the figure 11 The Tinerreg cam 11 shows the best gas content at higher engine speeds but not for lower engine speeds But for this engine and considering that MAR-I legislations cycle emission (power and torque) the Tinerreg cam 11 fits perfect

3 TEST BED RESULTS

Based on test matrix defined through the simulation a test bed was carried out in order to evaluate the best hardware configuration In order to optimize the development phase a test program was planned to guide the analysis and guarantee that all variants will be tested following the recommendation from the simulation shown in the figure 13

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 14 of 17

Figure 12 Test bed program

The figure 13 demonstrates the final results with the best hardware configuration Its

observed a better engine efficiency when applying Tiner cam 11 reaching 550 fuel consumption reduction

Figure 13 Final test result

X10 Tiner 7X10 Tiner 11X10 Reference Engine

Configuration

BS

FC

E

BSFC Emission Cycle [gkWh]

mis

sio

nC

ycle

[gkW

h]

Page 15 of 17

4 SUMMARY AND CONCLUSIONS

The implementation of iEGR was possible due to extensive usage of numerical simulation whose results were compared to mature engineering guidelines 1D flow and multi body dynamics simulations were of great importance to bound the prototype specifications and machining It was possible to drastically reduce the number of prototypes for test phase Potential level of residuals could be foresight using numerical models The internal EGR it is not sensitive to the swirl level considering 15 of tolerances The test phase presented a very good correlation with the simulation The result of performance and emission was higher than expected For fuel consumption reached 55 and for emission reached 3 in NOx+HC and 15 in PM even considering that the current engine already meets MAR-I legislation

5 NEXT STEPS

The next step is to evaluate increasing the power where MAR-I emission legislation is more restrict (lower NOx+HC value) and analyze the overall engine performance

References

1 Heywood J B Internal Combustion Engine Fundamentals MCGraw-Hill series in mechanical engineering Massachusetts 1988

2 httpwwwdieselnetcomstandardscycles at May 15th 2015 3 AVL Technical Report

Contact Information

Ricardo Ferreira Gasparini

Email ricardogasparininavistarcombr Tel +55 11 38823326 Flavio Augusto Levoto Cintra

Email flaviocintranavistarcombr Tel+55 11 38823290 Mario Luiz Lima Trevizan

Email mariotrevizannavistarcombr Tel +55 11 38823913

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DefinitionsAbbreviations

BSFC Brake Specific Fuel Consumption CFD Computational Fluid Dynamics CO Oxide of Carbon CO2 Dioxide of Carbon DEF Diesel Exhaust Fluid DoE Design of Experiment EBT Exhaust Back Temperature ECM Electronic Control Module EGR Exhaust Gas Recirculation ESC European Stationary Cycle ETC European Transient Cycle FID Fuel Ionization Detector FUP Fuel Unit Pressure FSN Filtered Smoke Number GVW Gross Vehicle Weight HC Hydrocarbon MDD Medium Duty Diesel MECE Mutually Exclusive and Collectively Exhaustive NDIR Non-Dispersed Infrared NOx Oxides of Nitrogen NVH Noise Vibration and Harshness PCP Peak Combustion Pressure PM Particulate Matter RAR Rear Axle Ratio RSM Response Surface Methodology SCR Selective Catalytic Reduction SOI Start of Main Injection

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All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the prior written permission of SAE ISSN 0148-7191 copyCopyright 2015 SAE International

Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE The authors solely responsible for the content of the paper

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All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise without the prior written permission of SAE ISSN 0148-7191 copyCopyright 2015 SAE International

Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE The authors solely responsible for the content of the paper