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EC Contract No. FP7 - 234338

Clean European Rail-Diesel

D6.3.1 Technology innovation for future measures beyond IIIB on diesel railway applications

Due date of deliverable: 31/05/2013

Actual submission date: 30/08/2013

Leader of this Deliverable: Roberto Palacín, Newcastle University (UK)

Reviewed:

Document statusRevision Date Description

0.1 22/05/2013 1st draft issue for comments (WP members only)0.2 31/07/2013 2nd draft issue for final comments following contributions made by

partners (WP members only)1 30/08/2013 Final version released

Project co-funded by the European Commission within the Seven Framework Programme (2007-2013)

Dissemination LevelPU Public XPP Restricted to other programme participants (including the Commission Services)

RE Restricted to a group specified by the consortium (including the Commission Services)

CO Confidential, only for members of the consortium (including the Commission Services)

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Start date of project: 01/06/2009 Duration: 48 months

Table of contents

1. BEYOND STAGE IIIB SCENARIO DESCRIPTION....................................................................4

1.1 INTRODUCTION....................................................................................................................4

1.2 SCENARIOS BEYOND STAGE IIIB......................................................................................4

1.2.1 SCENARIO 1............................................................................................................4

1.2.2 SCENARIO 2............................................................................................................6

1.2.3 SCENARIO 3............................................................................................................6

2. BEYOND STAGE IIIB POTENTIAL TECHNOLOGY SOLUTIONS.............................................8

2.1 INTRODUCTION....................................................................................................................8

2.2 SCENARIO 1 TECHNOLOGIES............................................................................................8

2.3 SCENARIO 2 TECHNOLOGIES............................................................................................9

2.4 DPF REGENERATION STRATEGIES................................................................................10

2.5 SCENARIO 3 TECHNOLOGIES..........................................................................................12

2.5.1 IN-ENGINE TECHNOLOGIES................................................................................12

2.5.2 AFTER-TREATMENT TECHNOLOGIES...............................................................14

3. BEYOND IIIB SYSTEMS INTEGRATION..................................................................................17

3.1 SCENARIO 1.......................................................................................................................17

3.2 SCENARIO 2.......................................................................................................................17

3.3 SCENARIO 3.......................................................................................................................18

3.3.1 IN-ENGINE TECHNOLOGIES................................................................................18

3.3.2 AFTER TREATMENT TECHNOLOGIES................................................................19

4. Tendering process framework....................................................................................................20

5. RECOMMENDATIONS..............................................................................................................22

5.1 RESEARCH AND DEVELOPMENT....................................................................................22

5.2 MANAGING THE RISK OF NEW TECHNOLOGIES...........................................................23

5.3 IMPROVING TIME TO MARKET.........................................................................................23

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List of Figures

Figure 1 Technologies considered in Scenarios 1, 2 and 3.............................................................5

Figure 2 Railway emission regulation timeline.................................................................................7

Figure 3. Potential impact and maturity of DPF related emerging technologies............................15

Figure 4 Potential impact and maturity of SCR related emerging technologies.............................15

Figure 5. Potential impact and maturity of emerging after-treatment system level technology themes...........................................................................................................................................16

Figure 6. overall tendering process framework and timeline.........................................................20

Figure 7. CleanER-D SP6 scenarios estimate timeline.................................................................21

Figure 8. estimated tender to delivery timeline and process..........................................................21

List of Tables

Table 1. Comparison matrix between EGR+DPF and other technologies.....................................10

Table 2 List of engine emerging technologies versus costs, fuel consumptions and weights.......13

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1. BEYOND STAGE IIIB SCENARIO DESCRIPTION

1.1 INTRODUCTION

This section considers the implications of potential measures beyond those of Stage IIIB. The likely dimensions of future measures are explored, and on the other hand the technological needs and requirements of such measures are outlined.

The NRMM directive update in 2004 that came with the inclusion of rail cars and locomotives, has brought with it political pressure on rail exhaust emissions. As a result of this there have been significant reductions in the limits set for PM and NOx emissions.

There appears to be political and societal momentum behind a convergence towards similar ultra-low levels of emissions for all transport modes beyond 2016. Evidence of such momentum, being the public and political pressure on road transport in the EU to ensure cleaner ambient air and to improve air standards; the focus being on PM and NOx emissions. Whilst the potential impact of this course of action on railway transportation is unknown, it must be kept in mind.

Despite potential further regulation and stricter limits, rail transport is performing at an above environmentally competitive level especially when taking into account the well-to-wheel approach and perspective and it is likely to continue to do so. In terms of total NOx and PM emissions, rail diesel produces extremely low emissions compared to other modes of transport. Historically speaking, from 1990 to 2008 the total emissions of rail diesel traction fell by 35% for NOX and PM, whilst total CO2 emissions fell by almost 50%.

In terms of fleet composition, it has been observed that there are decreasing numbers of diesel locomotives and increasing numbers of DMUs taking over part of the regional person transport from locomotives. Whilst there have been an increasing production of Stage IIIA engines reported, these were largely as a result of contracts secured prior to the reveal of Stage IIIB limits. Overall, a declining number of new diesel locomotives has been observed in recent history that could indicate operators anticipation of new legislative measures (and hence a hesitancy to procure new vehicles) and/or it could be a reflection of the current economic environment.

1.2 SCENARIOS BEYOND STAGE IIIB

Three key scenarios were explored in D6.2.2: Scenarios 1, 2 and 3. For the purposes of this section, all three scenarios will be examined. As can be seen in Figure 1 below, all three scenarios consider measures beyond Stage IIIB. These have been considered only for engines up to 560 kW.

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1.2.1 SCENARIO 1

The Scenario 1 study in D6.2.2 examined the limits of a single device exhaust after-treatment system concept for the 560 kW engine modelled for railcar applications. Two options were considered: (a) using only a SCR (Selective Catalytic Reduction) device and (b) using an EGR (Exhaust Gas Recirculation) system in conjunction with a DPF (Diesel Particulate Filter). For each of these cases, the brake specific emissions performance was simulated over the C1 homologation cycle (see ISO 8178-4) using the models described in D6.2.2.

Stage IIIB

Emissions

EGR

+ D

PF

SCR

EGR

+ D

PF +

SC

R

EMER

GIN

G T

ECH

.

SCENARIO 1 SCENARIO 2 SCENARIO 3

Stage IIIB

Emissions

EGR

+ D

PF

SCR

EGR

+ D

PF +

SC

R

EMER

GIN

G T

ECH

.

SCENARIO 1 SCENARIO 2 SCENARIO 3

Figure 1 Technologies considered in Scenarios 1, 2 and 3

The Scenario 1 study involved appropriately sizing the single device of the exhaust after-treatment system in each case. The main variables that determine the size of the device are the type, size and number of monoliths used in the device as well as the performance of the catalyst used. Assuming monoliths of specific type and size, and a catalyst of specific performance, the required number of monoliths was determined in each case on the basis of simulations and then an estimation of the volume and weight of the device was made on the basis of a generic device design template.

In the first case, a SCR device was sized to achieve NOx emissions at and below the Stage IIIB limit. As such, it was estimated that NOx emissions of 1.8 and 0.9 g/kWh could conceivably be achieved while the raw soot emissions of the engine remained at the Stage IIIB limit.

In the second case, a DPF was sized to meet the exhaust system backpressure limit while achieving soot emissions below the Stage IIIB limit. The soot emissions were estimated assuming average filtration efficiency greater than 95%. As such, it was estimated that soot emissions of

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0.005 g/kWh could conceivably be achieved using a DPF while the EGR system reduced the NOx emissions to the Stage IIIB limit.

It is noted that only the carbon soot particle component of the PM was modelled. The contribution to the PM emissions of other components of Diesel PM such as the organic fraction was not considered.

1.2.2 SCENARIO 2

Scenario 2 in D6.2.2 went a step further by studying the possible emissions performance that could be achieved for the same 560 kW engine, modelled for railcar applications, using in combination all three of the technologies considered in Scenario 1. Since, in so far as soot emissions were concerned, the Scenario 1 DPF design was compliant with the Stage IIIB limits, the primary aim of Scenario 2 was to size the SCR device so that, together with EGR, NOx emissions below the Stage IIIB limits could be achieved.

Most of the conditions applied in the Scenario 1 study were also applied in the Scenario 2 study, such as the exhaust gas conditions with EGR (as opposed to without EGR), the DPF design, and the SCR design criteria. Indeed, only the number of monoliths in the SCR device and the urea consumption rate were varied in Scenario 2. Therefore, a good basis was provided for comparison between Scenarios 1 and 2.

In Scenario 2 it was estimated that NOx emissions of 0.9 and 0.35 g/kWh could conceivably be achieved on the C1 cycle when using EGR in conjunction with a DPF and SCR device. Because both the EGR system and SCR device contributed to NOx reduction, the size of the SCR device in Scenario 2 was comparable to the size of the device in Scenario 1. Furthermore, in Scenario 2 the urea consumption rate was estimated to be significantly less compared to Scenario 1 since the raw engine NOx emissions were already reduced by the EGR system and consequently the SCR device was not so burdened.

In both the Scenario 1 and 2 studies, monoliths of different type and size, and catalysts of different performance, were not considered; the studies involved only an initial sizing of the DPF and SCR devices in terms of the number of monoliths required to meet the specified design criteria; a multi-parameter optimisation with respect also to the type and size of the monoliths and the assumed catalyst performances was not attempted. In this respect it is noted that the emissions performance of the DPF and SCR devices is sensitive to the volume specific surface area of the monoliths and the catalyst performances; therefore, the simulations in Scenarios 1 and 2 provide an estimation of emissions performance of the DPF and SCR devices only for the assumed monolith types and the assumed catalyst performances. Nevertheless, since a good basis is provided for comparison between Scenarios 1 and 2, the simulations also reveal the trend in device size and urea consumption rate with respect to emissions performance and exhaust after-treatment system concept (namely DPF or SCR versus DPF and SCR) when all other design variables are kept constant.

1.2.3 SCENARIO 3

Scenarios 1 and 2 examined on a quantitative basis the extent to which current state-of-the-art

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on-road engine and exhaust after-treatment system technologies might be able to achieve Stage IIIB and lower emissions performance if deployed in Diesel railcar applications. Scenario 3, on the other hand, was more forward looking and considered emerging on-road engine and exhaust after-treatment technologies, currently under development in the research domain, for which in most cases it is very difficult – or not yet possible - to make any quantitative predictions regarding their potential impact in areas such as fuel efficiency, emissions reduction, space and weight requirements, cost, etc. Therefore, the approach taken in Scenario 3 was to gather available information and data from research and industry sources regarding the most promising emerging technologies, and to make a qualitative assessment of their potential impact, giving quantitative impact estimates where possible.

Generally speaking, the stakeholders believe that any potential future emissions targets will have to be met by a combination of several technologies. It is thought that emerging engine technologies will be largely focused on reducing fuel consumption whilst pollutant emissions control will be a secondary aim. On the other hand, after-treatment system technologies (such as those examined in scenarios 1 and 2) will play the main role in controlling pollutant emissions. As the technologies in scenario 3 are on-road technologies, the information must be considered only for engines up to 650kW for railcar applications and it would not be correct to automatically assume that they could be extended to larger engines for heavy-haul locomotives.

Ultimately, it is believed that the technologies in scenarios 1 and 2 will be at the forefront of railcar technologies for the next ten to fifteen years. Beyond this timeframe, it is expected that scenario 3 technologies will begin to emerge as the state-of-the-art for railway application and contribute towards future emissions limits.

Figures 2 below show the historical movement of rail emissions regulation within the context of current technological limitations.

PM [g/kWh] EGR+DPF

2.5 Prior 2003 UIC I

0.25 2003 UIC II

0.2 2006 EU Stage IIIA

0.025 2012 EU Stage IIIB (Railcar) 2012 EU Stage IIIB (Locomotive) SCR

2 4 6 12 NOX [g/kWh]

Figure 2 Railway emission regulation timeline

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2. BEYOND STAGE IIIB POTENTIAL TECHNOLOGY SOLUTIONS

2.1 INTRODUCTION

It is generally accepted by the stakeholders that any future emissions targets will be met through the integration of several technologies (in the same vein as the EGR, DPF and SCR system described). The technologies to be used will depend on many different factors, such as the application context, the working duty cycle, costs, reliability, system integration, and so on.

Emerging after-treatment system technologies will be the primary tool in pollutant emissions control and they will be utilised based on the factors mentioned above. Emerging in-engine technologies will also help to control pollutant emissions; however their primary function will be to focus on fuel consumption reduction.

Some of the technologies explored in this section are the current state-of-the-art in the automotive sector as they aim to meet EURO VI emissions targets, and some are still in the research domain. As a result, these technologies are still at best in the research domain for the rail sector and their potential transferability is still unknown. Being on-road technologies, the information on these technologies can only be considered valid for engines with power output of up to 560kW and as such, place them as potentially useful for railcar applications (however it would be unreasonable to think such technologies could be directly transferred to heavy haul locomotives).

Depending on the future priorities of any regulatory measures or industry technology movements, any number of technological scenarios could unfold.

2.2 SCENARIO 1 TECHNOLOGIES

Scenario 1, described in D6.2.2 and D6.2.4, illustrates the emission control technologies currently available for railcar applications and the potential implications of their use in terms of emissions reduction.

Considering a single device after-treatment system concept for a 560 kW railcar engine, Scenario 1 compares the use of EGR (exhaust gas recirculation) in combination with a DPF (Diesel particulate filter) versus the use of a SCR (Selective Catalytic Reduction) device without EGR, where the DPF or SCR device is the single after-treatment device considered in each case.

The primary design parameter for the sizing of the SCR and DPF devices was the number of monoliths required for each device, as determined from simulations, on the basis of the assumed

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type and size of monoliths, and the assumed catalyst performances. The volume and weight of the devices was also estimated on the basis of a generic device design template.

The Scenario 1 results indicate that it could be possible for a 560 kW engine supplemented by a single device after-treatment system to achieve NOx or soot emissions below Stage IIIB limits.

SCR devices for use without EGR were sized and simulated for target NOx emissions of 1.8 and 0.9 g/kWh on the C1 cycle, while the soot emissions remained at the Stage IIIB limit. For the assumed type of monolith and catalyst performance, reducing NOx emissions to below the Stage IIIB limit required an increase in the volume (and therefore also the weight) of the SCR device since increased residence time was required. Additionally, it was predicted that the urea consumption rate increases as NOx emissions decrease, which indicates also the need for greater urea storage capacity.

Likewise, when using EGR to reduce the NOx emissions to the Stage IIIB limit, a DPF was sized that reduced the soot emissions to below the Stage IIIB limit while meeting the exhaust back pressure limit (however, as discussed above, it is noted that only the carbon soot particle component of the PM was modelled; the contribution to the PM emissions of other components of Diesel PM such as the organic fraction was not considered).

All of the above, while technically possible, pose significant systems integration challenges (see section 3 of this report for further details).


Scenario 2 in D6.2.2 and D6.2.4 took a step further by examining the combined use of state-of-the-art EGR, DPF and SCR technologies to achieve emissions levels equal to and below those considered in Scenario 1. EGR and SCR were used in combination to reduce NOx emissions to 0.9 and 0.35 g/kWh on the C1 cycle while the DPF was used as before to reduce soot emissions to below the Stage IIIB limit.

Both EGR and SCR reduce NOx emissions; therefore, a lower urea consumption rate was required in Scenario 2 to achieve the same NOx emissions levels as in Scenario 1 because the NOx emissions had already been reduced by EGR.

Although Scenario 2 indicates that it could be possible to achieve NOx and soot emissions below the Stage IIIB limits with the combined use of EGR, DPF and SCR, as in Scenario 1 there are concerns regarding the weight and volume of the overall system. The urea consumption rate (and hence also the required urea storage volume) is less in Scenario 2 compared to Scenario 1; however, the size of the EGR system and of the SCR device in Scenario 2 is comparable to that in Scenario 1. Likewise, the size of the DPF in Scenario 2 is comparable to that in Scenario 1. Therefore, the use of EGR and two after-treatment devices in Scenario 2 increases the weight and volume of the system compared to Scenario 1, in which only a single after-treatment device is used, and this could have a significant impact on the design of the railcar.

Additionally, the arrangement of the DPF and SCR devices must be considered. Placing the DPF upstream or downstream of the SCR device can have advantages and disadvantages for the

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operation of the two devices (as discussed further in Section 3).

Furthermore the additional complexities in the system in scenario 2 bring additional questions over controls and diagnostics as well as lifecycle costs. A complex control for the EGR rate is necessary and the two after-treatment devices call for further controls and diagnostics. Therefore the control unit is more prone to errors and therefore reliability is bound to get worse. Also the more components in the scenario 2 system means that lifecycle costs overall are higher than in scenario 1, as the additional components have a negative impact on fuel consumption.

If potential future measures against emissions were to further target NOx, the current state of the art could theoretically achieve those beyond Stage IIIB. These reductions would have to be considered within the context of those issues raised above and the potential impacts they might have on the design and performance of the rail vehicle bringing in considerable systems integration challenges. There are trade-offs to be considered, and whilst reducing emissions further could be of importance in terms of being environmentally friendly, the steps to reducing these emissions might result in environmentally unfriendly and less sustainable consequences (i.e. higher fuel consumption).

Currently fuel is the most important factor in determining lifecycle cost of a vehicle, as it represents 80% of the investment cost over the whole lifecycle of the railcar. As a result, railcar operators have low fuel consumption as one of their highest priorities. It is possible however, for the fuel increase associated with more complex after-treatment systems to be mitigated with emerging technologies.

Table 1 shows the five evaluated emissions reduction technologies in scenarios 1 and 2, broken down into four key areas of assessment; overall space, overall weight, lifecycle cost and emissions reduction potential. The scenario 1 system of an EGR unit coupled with a DPF module is set as the baseline for comparison.

technology Overall space Overall weight LCC Reduction potential

EGR+DPF - - - -

SCR lower lower equal higher

High SCR lower lower higher higher

EGR+DPF+SCR higher higher higher higher

EGR+DPF+high SCRhigher higher higher higher

Table 1. Comparison matrix between EGR+DPF and other technologies.

2.4 DPF REGENERATION STRATEGIES

The use of a DPF to control PM emissions incurs the additional operational complexity of regenerating the DPF. The DPF controls PM emissions by physically capturing the PM within the porous substrate of the device and therefore necessitates the continuous or periodic removal of the accumulated PM. DPF regeneration aims to remove mainly the carbon soot particle

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component of the accumulated PM by chemical oxidation to gaseous products; ash must be removed periodically by other methods. Since the regeneration process involves elevated temperatures, it can potentially damage the DPF.

Regeneration can be accomplished either passively or actively. Passive regeneration strategies promote soot oxidation at the temperature of the exhaust gas under regular operating conditions of the engine using catalysts for the oxidation of the soot by oxygen and/or catalysts for the oxidation of the NO in the exhaust gas to NO2 which then oxidises the soot. As such, passive regeneration strategies aim to regenerate the DPF continuously by oxidising the soot at approximately the same rate at which it accumulates. On the other hand, active regeneration strategies promote soot oxidation by raising the exhaust gas temperature using externally supplied energy, for example using catalytic fuel combustion or a fuel burner, possibly also in conjunction with engine management methods. As such, active regeneration strategies can be used to regenerate the DPF periodically whenever required.

The overriding factor in the choice between passive and active regeneration strategies is the requirement for safe and reliable regeneration. Passive regeneration strategies can only be used alone if the exhaust gas temperatures are sufficient to ensure that the soot is removed from the DPF by oxidation at a rate equal to or greater than the rate at which it accumulates by filtration. If this is not possible then an excessive amount of soot will accumulate in the DPF resulting in the risk of uncontrolled regeneration or clogging of the filter. To prevent this from happening, an active regeneration strategy is necessary to periodically increase the exhaust gas temperature sufficiently for the DPF to regenerate. An active regeneration strategy can also be used on its own. Since the use of active regeneration under conditions that are favourable for passive regeneration may incur an unnecessary fuel penalty, the combined use of active and passive regeneration strategies may be necessary and advantageous.

The regeneration process involves elevated temperatures that can damage the DPF if the process is not carefully monitored and controlled. In particular, a large soot mass load in the DPF can cause the oxidation reactions to become self sustaining because of the large heat release and therefore result in an uncontrolled regeneration. Unless the DPF is designed to adequately withstand uncontrolled regeneration, the very high temperatures that can be encountered during uncontrolled regeneration can damage the DPF substrate resulting in reduced filtration efficiency and increased PM emissions due to leaks or increased backpressure due to blockages or even catastrophic failure of the substrate and a hazard for the vehicle.

Furthermore, it is important to minimize the fuel penalty of an active regeneration strategy, whether it is used together with a passive regeneration strategy or not. Firstly, the regeneration frequency must be optimised in order to minimize, on the one hand, the fuel penalty incurred by overly frequent active regeneration and, on the other hand, the fuel penalty incurred by the increased backpressure consequent of infrequent active regeneration. Secondly, the temperature and duration of each regeneration event must be optimised with respect to the fuel penalty it incurs.

Within the context of the Scenario 1 and 2 studies in D6.2.2, and as reported in D6.2.3, a passive regeneration strategy was simulated for the DPF sized for the modelled 560 kW engine with EGR.

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The simultaneous loading and passive regeneration of the catalyzed DPF (CDPF) was simulated under steady state conditions at six of the eight engine operating points on the C1 cycle and also over an approximated DMU railcar driving cycle (see D6.2.3).

The steady state simulations indicated that at three operating points on the C1 cycle the exhaust gas temperature was sufficiently high for the CDPF to reach within 2-3 hours an equilibrium soot mass load below the critical value requiring active regeneration but at the other three operating points the exhaust gas temperature was too low and the CDPF continued to load indefinitely; however, at the latter points, the time required to reach the critical soot mass load or to exceed the maximum allowable incremental pressure drop due to soot loading was greater than about 10 hours.

The DMU driving cycle simulations indicated that, after an initial loading period, the CDPF operated within an equilibrium soot mass load range that was below the critical value requiring active regeneration; the CDPF loaded while the engine operated at low exhaust gas temperature points and then partially regenerated when the engine operated at the higher exhaust gas temperature points.

However, as discussed above, an active regeneration strategy could also be necessary.

Furthermore, the above simulated passive regeneration behaviour is specific for the modelled engine, the modelled CDPF and the assumed performance of its catalyst, and for the particular driving cycle approximation.


2.5.1 IN-ENGINE TECHNOLOGIES

Heavy duty road technologies currently being considered to meet EURO VI regulations are thought to be the most likely candidates for transfer to future railcar application. Emerging in-engine technologies are expected to be driving future improvements in engine efficiency. At the same time, emerging exhaust after-treatment technologies are expected to be the primary force in tackling pollutant emissions. For more information on all of the areas discussed below, please refer to D6.2.2.

As discussed in D.6.2.4, the emerging technologies explored, that are potentially transferable to the rail sector, are largely the subjects of on-going development and research for on-road heavy-duty engine efficiency improvement. These emerging technologies have been identified through surveys carried out based on previous available studies. These studies are identified in Table 6-1 found in section 6.2 of D.6.2.4.

The technologies that were identified must be only considered for engines up to 560kW power output, and cannot be extended to those larger engines that may be applied in heavy haul locomotives. Table 2 of these emerging technologies and their estimated impacts on costs, fuel consumption and weight can be found below (for more information refer to Section 6.2.2 of

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D6.2.4):

TECHNOLOGY

ENGINE COST INCREMENT (%)

(engine baseline cost = 70k€)

FUEL EFFICIENCY IMPROVEMENT (%)

(Euro5 as baseline value)

Additional weight related to engine

weight [%]

Fuel injection systems From 0 to 1% From 1.5 to 3.2 % From 0 to 1%

Advanced EGR From 0.5 to 1% From 1 to 1.5% From 0 to 2%

Advanced turbochargers From 0.3% to 1% From 1 to 2% From 0 to 2%

Combustion system design From 0.5% to 1.5% From 1 to 3% From 0 to 1%

Advanced combustion ~10% From 1 to 2% 0

Advanced combustion control From 0.1% to 0.15% From 1 to 3% 0

Variable valve actuation ~0.3% ~1% From 0.5 to 3%

Waste heat recovery From 5% to 20% From 4 to 8% From 6 to 20%

Electrification of engine-driven accessories and auxiliaries From 0% to 2% From 0 to 3% From -1 to 2%

Table 2 List of engine emerging technologies versus costs, fuel consumptions and weights

Whilst the technologies listed above can contribute individually, and this is what those figures are based on, it is also important to consider the interactions between each emerging technology when and if they are combined. Some technologies will have a negative influence on each other, and hence the effects on fuel improvement cannot be summed and still be accurate estimations.

Most of the emerging technologies for automotive application are expected to have a return on investment of less than one year, whilst advanced combustion and waste heat recovery technologies are expected to have ROI exceeding one year (approximately 3.5 and 1.7 years respectively). It is important to note that these estimations assume the lowest fuel improvement and the highest cost increment, and hence they are the most pessimistic estimations for these technologies (for more information refer to section 6.2.2 of D6.2.4).

It is to be expected that as work towards lower emissions continues, there will be higher fuel consumption penalties. For example, an EGR system not only requires a cooling system but also a DPF unit running in tandem to counteract PM emissions, hence this adds weight to the rail vehicle and ultimately imposes a fuel penalty. As shown by Table 2, aside from emerging “Waste

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heat recovery” technologies, most of the emerging technologies explored have a relatively minimal weight impact. This is largely due to the fact that they are in-engine technologies and thus only affect the engine.

2.5.2 AFTER-TREATMENT TECHNOLOGIES

In D6.2.4, a qualitative assessment of the potential impact of the most promising emerging after-treatment technologies, currently in the research phase of development, was made.

The technologies were grouped as follows: DPF related:

o DPF with membrane coatingo DPF with heat recoveryo New DPF substrate materialso Catalyst synthesis and applicationo Electrified DPF

SCR related:o Solid ammonia storageo Zonal coating of SCRo LNT (Lean NOx Trap) + SCR

System level technology themes:o On-board monitoring and diagnosticso Fuel-tailored emission control systemo Precious metal substitution

The potential impact of the technologies in each group was considered in terms of:

Pollutant emissions reduction potential

Cost reduction potential (manufacturing cost + system operating cost)

After-treatment system size and/or weight reduction potential

Technology maturity

As assessed on a qualitative basis in D6.2.4, the potential impact of the above technologies can be visualized using the following spider diagrams for the three technology groups. For the interpretation of these diagrams it is noted that the position of each technology on each axis of its diagram is relative to the other technologies in its group / diagram; the position on similar axes of technologies in different groups / diagrams should not be compared.

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Pollutant Emissions Reduction

Technology Maturity

Cost Reduction

Size/Weight Reduction

DPF with membrane coating

DPF with heat recovery

New DPF substrate materials

Catalyst synthesis and application

Electrified DPF

Low High

Figure 3. Potential impact and maturity of DPF related emerging technologies

0

1

2

3

4


Technology Maturity

Cost Reduction


Solid ammonia storage

Zonal coating of SCR

LNT+SCR

Low High

Figure 4 Potential impact and maturity of SCR related emerging technologies

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Technology Maturity

Cost Reduction


On-board monitoring & diagnostics

Fuel-tailored emission control system

Precious metal substitution

Low High

Figure 5. Potential impact and maturity of emerging after-treatment system level technology themes

Emerging exhaust after-treatment technologies focus mainly on increasing emissions reduction performance, reducing space requirements, reducing the fuel penalty associated with their use, improving system monitoring and control, and reducing their production cost.

In the area of particulate emissions control, emerging technologies focus mainly on improved re-generation performance and monitoring of the DPF since this is important for fuel economy.

In the area of NOx control, emerging alternative ammonia storage media and LNT+SCR strate-gies could significantly reduce space requirements.

Also, of potentially high impact on rail applications are emerging catalyst synthesis and applica-tion technologies that could enable the integration of multiple after-treatment functionalities into a single device since this could significantly reduce the space and weight requirements of the after-treatment system.

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3. BEYOND IIIB SYSTEMS INTEGRATION

3.1 SCENARIO 1

Whilst the size and weight demands of the EGR, SCR and DPF devices are worthy of significant consideration, there are other issues to be considered. There are heat emissions caused by after-treatment systems, the more complex mechanical vibrations behaviour of the system as a whole and the further required piping for the system.

The use of EGR, DPF and SCR devices calls for a cooling unit and strategy. The main considerations for such units are whether the unit is underfloor or roof installed, the number of cooling circuits required and whether the cooling unit has an air-to-air or air-to-water heat exchanger. To mitigate the requirements of the cooling unit, the cooling device could be installed on the roof as opposed to being installed underfloor. Relative to the DPF and EGR strategy, the SCR strategy requires less cooling in terms of the cooling unit size, weight and capacity. In the case where these variables could be limiting factors, it could be preferential to opt for an SCR strategy on the basis of the reduced cooling unit requirements.

For each device, the lifetime and lifecycle costs of the unit has to be factored in to the design of the system. Something that affects both of these factors is the frequency and the extent of maintenance, of which there are two types, preventative maintenance and corrective maintenance. Eventually both after-treatment systems, both SCR and DPF will have to be replaced at some point, which can be influenced by many factors including temperature, load profile and fuel quality (biofuels can lead to an increase in ash deposits, that can shorten the life of filters) to name a few. Increasingly railway operators have looked to base their investment decisions based on lifecycle costs, rather than just purchase price (for more detailed information on these factors, see section 3.3 of D6.2.4).

3.2 SCENARIO 2

The use of two rather than one after-treatment devices in Scenario 2 introduces an additional element of complexity when it comes to system design and integration. Apart from the integration concerns of Scenario 1, the interaction between all three components (EGR, DPF and SCR) has to also be considered.

A technically important issue is the arrangement of the DPF and SCR devices. Both sequences are feasible. There are two issues to consider, on the one hand efficiency and on the other hand regeneration of the DPF.

When the devices are installed in line the downstream device has a lower average temperature which leads to slower chemical reactions and therefore to lower efficiency. Also the warm-up time during the starting process is influenced in a negative way.

Mounting the DPF upstream of the SCR supports the passive regeneration of the DPF and this can have a positive effect on the active regeneration intervals. However, during the starting process more time is required until the SCR begins to work properly.

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If the devices are installed the other way around, then the DPF can be used as an ammonia slip-catalyst. However, it must be kept in mind that the substrate of the SCR catalyst can be de-stroyed by excessive temperatures and this has to be considered in the case of an active regen-eration strategy.

Therefore, it is not possible to give common advice about the arrangement; it always depends on the individual application.

Also, the use of two rather than one after-treatment devices in Scenario 2 increases the space and weight requirements. This could adversely effect where the vehicle can operate (due to clearance gauges on infrastructure), and the effect of increased weight on acceleration could also impact punctuality.

Furthermore, the use of two rather than one after-treatment devices in Scenario 2 increases system complexity and this has a knock-on effect on lifecycle cost. The two after-treatment devices increase the backpressure in the exhaust system, which increases fuel consumption. Also, more complex control and diagnostic systems are required, which increases system cost and the likelihood of failure.

3.3 SCENARIO 3

3.3.1 IN-ENGINE TECHNOLOGIES

For further details see section 7.2 of D6.2.2

In addition to the benefits described in sections 2.5.1, a number of emerging in-engine technologies could have potential synergies with existing or other emerging technologies. Whilst emerging in-engine technologies, generally speaking look to improve engine efficiency and fuel consumption, a select few technologies can also offer these synergies.

Electrifying engine-driven accessories such the water pump, or air compressor, will realise their full potential when used as a package on hybrid vehicles in particular. Likewise, if electric turbo compounds are successfully transferred from the research domain, the maximum effect will be achieved when applied to hybrid electric trains.

Technologies such as variable valve actuation allow the use of non-conventional combustion modes, and alternatives to the standard Diesel combustion cycle, such as Low Temperature Combustion (LTC), Homogeneous Charge Compression Ignition (HCCI) and Premixed Charge Compression Ignition (PCCI) can lead to lower overall emissions or lower costs of after-treatment solutions.

On the other hand, some emerging technologies will have to be carefully considered as they may not be conducive to certain goals. For example, whilst low temperature EGR is a promising technology that could improve engine efficiency and lower NOx emissions, it may not be compatible with certain energy recovery systems or after treatment systems.

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3.3.2 AFTER TREATMENT TECHNOLOGIES

Until recently, the progression of the state-of-the-art in Diesel exhaust after-treatment centred mainly on the development of separate mono-functional after-treatment devices to control particular types of emissions, as these began to be regulated.

However, the continuous lowering of emissions limits and the expanding range of regulated emissions has began to necessitate in many applications the combined use of several mono-functional after-treatment devices, as considered for example in Scenario 2. As discussed above, functional synergies as well as conflicts may arise in this situation. As such, in those cases where significant synergies are possible, the functionalities of separate devices have often been integrated into one device by placing the substrates of the devices in close proximity within a common housing; in other words, integration complexity has been reduced by integrating the functionalities at the device scale rather than at the system scale.

Along these lines, several of the emerging after-treatment technologies considered in Scenario 3 share the common goal of further reducing integration complexity by facilitating functional integration at the substrate and material scales, for example through the development of new substrate material technologies, catalyst synthesis and application technologies, and monitoring and diagnostics technologies, since this can enable multi-functional devices that simultaneously perform several after-treatment tasks, such as oxidation catalysis, PM control and NOx control. This endeavour is particularly challenging and it remains to be seen how much progress can be made in this direction.

Most of the other emerging after-treatment technologies considered in Scenario 3 also aim to reduce integration complexity, indirectly, by increasing the emissions reduction performance of mono-functional devices while reducing their size and weight, reducing their fuel penalty, and increasing their durability.

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4. TENDERING PROCESS FRAMEWORK

The process of diluting new technology into the market is a long and complex one that is not only constrained by the speed of progress in technology but also constrained by legal frameworks, demand from operators and strategic decisions made years before the emergence of a new technology.

It is estimated that the timeline to realise this process has three steps, namely:

Time to develop the technical solution (responsible: engine manufacturers);

Time to integrate solutions (systems integrators);

Time to market i.e. homologation (operators and all)

The above timeline is related to the tendering process. In addition there is a pre-tender period where OEMs invest capital and time to R&D of components.

The following diagram represents the overall timeline involved in the tendering process.

Figure 6. overall tendering process framework and timeline.

Regarding the three scenarios considered in this report, the estimated timeline is represented in figure 7.

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Figure 7. CleanER-D SP6 scenarios estimate timeline.

In addition, once the tender is published, the timeline for delivery is estimated to be between three and five years, as shown in figure 8.

Figure 8. estimated tender to delivery timeline and process.

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The stimulus for any product or deliverable (that may contain new technology) is the tender from rail operators to the integrators. Typically these tenders will have roundabout stipulations, ie. the vehicle must meet stage IIIB standards, but will not specify the way in which these must be met. This is in the interest of fair play and transparency and ensures that each integrator has an equal chance of successfully bidding on the tender. As part of putting together their bids, the integrators make sure to put out tenders for the required technology to manufacturers.

Generally speaking, the tendering process can take 1-2 years before the successful bidder is informed that they have won the contract. However on some occasions, this could be further delayed if other bidders appeal and in rare occasions, this process could be forced to start all over again if an integrator is deemed to not have been given a fair chance of winning the contract.

Once a successful integrator has been chosen, they build and test the vehicle and ensure it is homologous. After ensuring that the vehicle meets the standards set out by the tender, it is delivered to the operator. This stage typically takes between 2-3 years.

Assuming that the technology is available to satisfy the needs of the tender, an estimate of the timeframe of this overall process is between 3-6 years. However, it can be the case that the technology required by the tender is not yet available for rail application or it may not be ready for application in other sectors. If this happens to be the case, there must be a process added on to the overall timeline before the tender stage. This process covers the time taken to develop the technology to be ready for rail application, and can take between 4-5 years as an optimistic estimate. Hence a new vehicle with state of the art technology could take at least 7 years to be diluted into the fleet and enter operation. In the longest instances, it has taken 12 years for this process to reach completion.

It then must be considered that once an operator or an integrator is locked into a contract, there may be a delay because of the pipeline of work between the related actors in the value chain. If an operator needed 5 new vehicles and ordered them pre-Stage IIIB standards, their new vehicles may arrive 3-6 years later and immediately be behind the regulation curve.

5. RECOMMENDATIONS

5.1 RESEARCH AND DEVELOPMENT

Continued support for research into further fuel reduction and emission reduction technologies is needed, including such research into innovative technical solutions that reduce emissions by internal measures. The technologies explored in Scenario 3 could help to significantly improve current systems, however further research will be needed to quantify their effects and whether they are compatible with the systems that are currently in place.

Additionally, such researched technologies should ideally look to provide economically viable solutions that have a positive impact on lifecycle cost at the same time as improving emissions and fuel performance.

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5.2 MANAGING THE RISK OF NEW TECHNOLOGIES

The potential for new technologies to be applied to rail raises some interesting questions surrounding the risks that can arise when pursuing them. Quickly proceeding down one path of technologies or solutions could lead to a more lucrative missed opportunity that was not pursued. In such situations, an “opportunity cost” is paid; for example, the benefits of pursuing technology A and B may be +1 and +2 units of additional emissions performance, hence if technology A was chosen over technology B, then the opportunity cost of this decision would be the missed unit of emissions performance. Unfortunately, for most decisions it is difficult to quantify these costs/benefits as many times they are made on incomplete information.

Additionally, whilst the opportunity cost of such missed technology propositions can be immediate, they can also have long term effects that could position the rail industry in the wrong place strategically in relation to the global transport market and other modes of transport. This could lead to further subsequent opportunities being lost or not presenting themselves. Hence careful consideration and assessment is needed before deciding upon which technologies or measures are right for the future of the industry.

5.3 IMPROVING TIME TO MARKET

It has been recognised (see section 3.3) that the interplay along the value chain between operators, systems integrators and engine manufacturers could be improved, and that in its current state is unable to keep up with the rapid changes in technology.

The lengthy tendering process for each interaction (operators to integrators and integrators to manufacturers) results in a lag from when technology is available and ready to be used, to when it is finally implemented and being utilised in the operating fleet.

Reducing the time of the process or simplifying this process could be very beneficial, not only to those involved in the chain (as they could dedicate less time and resources) but also to the industry as a whole as it would reduce the time to market for new, more efficient and more environmentally friendly technologies, always keeping in mind the complex and lengthy development process of such technologies.

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