testing and modelling of a 2 power strokes per revolution

1

Testing and modelling of a 2 power strokes per revolution opposed piston engine with an

innovative kinematics

José R. Serrano1, Héctor Climent1, J. Javier López1, Alejandro Gómez-Vilanova1, Juan Garrido-Requena2, Manuel J. Luna-Blanca2 and F. Javier Contreras-Anguita2

(1)Universitat Politècnica de València. CMT-Motores Térmicos(2)INNEngine

2

Index

1. Engine concept/layout2. Test campaign/combustion analysis 3. Engine modelling and validation 4. Results and analysis5. Predictive/forward parametric analysis6. Conclusions

3

Index


4

Engine concept/layout

• 4-cylinder 0.5 l gasoline opposed piston, 2 stroke-based ICE.• 2 power strokes per engine revolution.• Innovative mechanical architecture to connect the pistons with the crankshaft,

based on a cam-follower mechanism. • Intake and exhaust ports variable opening and closing timing. • Variable volumetric compression ratio. • Small and light, simple, efficient and high-power density engine.

5

Engine concept/layout

• Pairs of cylinders burning at the same time, to different exhaust lines (pressure pulses interference avoidance).

• Port injection.• 1-D air filling behavior: following the perfect displacement

approach.• Small and light, simple, efficient and high-power density

engine.

6

Index


7

Test campaign/combustion analysis

• Analysis of the cycle to cycle dispersion.

• Picture corresponds to first 30 cycles of each working point and cylinder number 1. -20 0 20 40

20

40

p[ba

r]

-20 0 20 40

0

10

20

HR

R[J

/CAD

]

-20 0 20 40

Crank angle [CAD]

0

50

100

MFB

[%]

-20 0 20 40

20

40

-20 0 20 40

0

10

20

-20 0 20 40

Crank angle [CAD]

0

50

100

1000 rpm, 59.2 Nm 1200 rpm, 59.6 Nm

1

23

4

8


• Analysis of the cylinder to cylinder dispersion.

• In the picture, lines correspond to first cycles of each cylinder.

• Working point 1200 rpm and 59.6 Nm.-20 -10 0 10 20 30 40 50

10

20

30

40

p[ba

r]

-20 -10 0 10 20 30 40 50

0

10

20

HR

R[J

/CAD

]

-20 -10 0 10 20 30 40 50

Crank angle [CAD]

0

50

100

MFB

[%]

cyl 1

cyl 2

cyl 3

cyl 4

1

23

4

1000 rpm, 59.2 Nm

9


• Comparison VS conventional 4 stroke ICE SI combustion.– Cycle-to-cycle variability comparison.– Cylinder-to-cylinder variability comparison.– Combustion efficiency differences.

Point A (1000 rpm / 59.2 Nm) Point B (1200 rpm / 96.7 Nm)

CA10[CAD]

CA50[CAD]

CA90[CAD]

pmax [bar]

Effcom[%]*

CA10[CAD]

CA50[CAD]

CA90[CAD]

pmax [bar]

Effcom[%]*

AverageSI Engine -1.5 4.97 13.88 39.95 82.89 -2.94 6.16 14.11 38.53 79.23

InnEngine -2.95 4.9 13.14 32.41 59.75 -2.39 6.05 14.72 31.62 60.55

Cyc-to-cycvariability

SI Engine 1.22 1.57 2.12 1.95 1.17 1.23 1.69 2.45 1.89 0.98

InnEngine 0.81 1.47 3.25 3.72 2.17 0.73 1.4 3.85 3.71 2.33

Cyl-to-cylvariability

SI Engine 0.78 1.14 1.69 1.76 0.66 0.70 1.02 1.41 1.3 0.4

InnEngine 1.71 2.99 6.42 3.76 1.74 1.30 2.41 6.73 3.16 1.9

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• There are no misfires on normal operation, although the variability of heat released is higher than in SI conventional combustion it can be assumed that all the fuel is burned

• The cycle to cycle and cylinder to cylinder variability on the heat released and in the TOC is higher than in SI conventional combustion. The previous might be cased by higher scavenging variability (residual gases, short-circuit)

• The energy obtained from fuel is slower than expected (a 20% less than in SI combustion) that can be explained by a 20% of short-circuit

11

Index


12

Engine modelling and validation

• In-house 1D simulation software for Virtual Engine MODelling: VEMOD. Developed by the CMT-Motores Térmicos research institute.

• Copes with any engine aspect.• The model timing and kinematic checked. For this purpose,

instantaneous experimental data is taken as basis.• Possibility to differentiate whether perfect displacement/mixture

during gas exchange process.• Once the model is (partially) validated, some studies are pretended:

– Parametric studies: engine configuration, rpm, boundaries, boosting degree, load degree…

– Analysis of the experimental results can be also pretended, to detect engine key points (short-circuit, gas exchange process…)

13


14

Results and analysis(Perfect displacement)

(Perfect displacement) (Perfect mixture)

(Perfect mixture)

0,0145 kg/s

0,01 kg/s

0,03 kg/s

87 Nm

67 Nm

128 Nm133 Nm

0,031 kg/s

0,0145 kg/s

0,01 kg/s

0,03 kg/s0,031 kg/s

87 Nm

67 Nm

128 Nm133 Nm

15


• 1000 rpm.• 87 Nm.• Perfect displacement approach (too

much fresh mixture trapped in the model).

• Cylinder pressure exceeds the experimental instantaneous data.

• Lack of short-circuit

16


• 1000 rpm.• 87 Nm.• Perfect mixture approach (exact

trapped fresh mixture).• Cylinder pressure matches the

experimental instantaneous data.• Hypothesis of short-circuit is

confirmed.

17

Index


18

Results and analysis

𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺 𝒓𝒓𝑺𝑺𝒓𝒓𝒓𝒓𝒓𝒓 =𝑰𝑰𝑺𝑺𝑰𝑰𝑺𝑺𝒓𝒓 𝒎𝒎𝑺𝑺𝒎𝒎𝒎𝒎

𝑹𝑹𝑺𝑺𝑹𝑹𝑺𝑺𝒓𝒓𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺 𝒎𝒎𝑺𝑺𝒎𝒎𝒎𝒎

𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝑒𝑒𝑒𝑒𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑒𝑒 =𝑅𝑅𝑒𝑒𝑅𝑅𝑇𝑇𝑇𝑇𝑇𝑇𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚𝐼𝐼𝑇𝑇𝐼𝐼𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚

𝑆𝑆𝑒𝑒𝑇𝑇𝑆𝑆𝑒𝑒𝑇𝑇𝑇𝑇𝑒𝑒 𝑒𝑒𝑒𝑒𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑒𝑒 =𝑅𝑅𝑒𝑒𝑅𝑅𝑇𝑇𝑇𝑇𝑇𝑇𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚

Perfect displacement Perfect mixture

OPERATIVE ZONE

19


𝑆𝑆𝑒𝑒𝑇𝑇𝑆𝑆𝑒𝑒𝑇𝑇𝑇𝑇𝑒𝑒 𝑇𝑇𝑇𝑇𝑅𝑅𝑇𝑇𝑟𝑟 =𝐼𝐼𝑇𝑇𝐼𝐼𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚

𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑒𝑒 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚

𝑻𝑻𝒓𝒓𝑺𝑺𝑻𝑻𝑻𝑻𝒓𝒓𝑺𝑺𝑺𝑺 𝑺𝑺𝑹𝑹𝑹𝑹𝒓𝒓𝑺𝑺𝒓𝒓𝑺𝑺𝑺𝑺𝑺𝑺𝒆𝒆 =𝑹𝑹𝑺𝑺𝒓𝒓𝑺𝑺𝒓𝒓𝑺𝑺𝑺𝑺𝑹𝑹𝒎𝒎𝑺𝑺𝒎𝒎𝒎𝒎𝑰𝑰𝑺𝑺𝑰𝑰𝑺𝑺𝒓𝒓 𝒎𝒎𝑺𝑺𝒎𝒎𝒎𝒎

𝑆𝑆𝑒𝑒𝑇𝑇𝑆𝑆𝑒𝑒𝑇𝑇𝑇𝑇𝑒𝑒 𝑒𝑒𝑒𝑒𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑒𝑒 =𝑅𝑅𝑒𝑒𝑅𝑅𝑇𝑇𝑇𝑇𝑇𝑇𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚


OPERATIVE ZONE

20


𝑆𝑆𝑒𝑒𝑇𝑇𝑆𝑆𝑒𝑒𝑇𝑇𝑇𝑇𝑒𝑒 𝑇𝑇𝑇𝑇𝑅𝑅𝑇𝑇𝑟𝑟 =𝐼𝐼𝑇𝑇𝐼𝐼𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚

𝑅𝑅𝑒𝑒𝑒𝑒𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑒𝑒 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚

𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 𝑒𝑒𝑒𝑒𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑇𝑇𝑒𝑒𝑒𝑒 =𝑅𝑅𝑒𝑒𝑅𝑅𝑇𝑇𝑇𝑇𝑇𝑇𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚𝐼𝐼𝑇𝑇𝐼𝐼𝑒𝑒𝑅𝑅 𝑚𝑚𝑇𝑇𝑚𝑚𝑚𝑚

𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺𝑺 𝑺𝑺𝑹𝑹𝑹𝑹𝒓𝒓𝑺𝑺𝒓𝒓𝑺𝑺𝑺𝑺𝑺𝑺𝒆𝒆 =𝑹𝑹𝑺𝑺𝒓𝒓𝑺𝑺𝒓𝒓𝑺𝑺𝑺𝑺𝑹𝑹𝒎𝒎𝑺𝑺𝒎𝒎𝒎𝒎𝑻𝑻𝒓𝒓𝑺𝑺𝑻𝑻𝑻𝑻𝑺𝑺𝑹𝑹𝒎𝒎𝑺𝑺𝒎𝒎𝒎𝒎


OPERATIVE ZONE

21


(Perfect displacement)

(Perfect displacement) (Perfect mixture)

(Perfect mixture)

OPERATIVE ZONE

OPERATIVE ZONE

22

Index

1. Engine concept/layout2. Test campaign/combustion analysis 3. Engine modelling and validation 4. Results and analysis5. Predictive/forward parametric analysis

1. Direct injection2. Combustion pre-chamber

6. Conclusions

23

(Direct injection)(Perfect displacement)

(Port injection)(Perfect displacement)

Predictive/forward parametric analysis

• Calculations keeping the same engine configuration. • Unique modification: From port injection to direct injection. • Perfect mixture approach will be the one selected for this study.• No unburned fuel is short-circuited (DI).• Inlet pressure imposed according to the plots, exhaust pressure 1 Bar.

OPERATIVE ZONE

25






OPERATIVE ZONE

OPERATIVE ZONE

26

Index



6. Conclusions

27

Index



6. Conclusions

28


• Why working under stoichiometric mixture? What if…– A given pre-chamber is installed?– Lean combustion could be achieved and stable?

• Fr=0.6 has been forced into the simulations in order to identify if the target working zone could be reached: 30kW from 1500 to 3000 rpm and 230 g/kWh.

• It is necessary to work under FR close to 0.6 in order to guarantee NOx generation avoidance, since catalyst implementation is not possible in this engine configuration.

29


(Direct injection)(Perfect displacement FR=1)

(Direct injection)(Perfect mixture FR=0.6)


(Direct injection)(Perfect mixture lean FR=0.6)

30



(Direct injection)(Perfect mixture FR=0.6)


(Direct injection)(Perfect mixture lean FR=0.6)

31

Index


32

Conclusions

• Engine has been designed, assembled and tested.• Combustion analysis has been performed.• Engine model has also been developed and partially

checked: kinematics, combustion, air filling…• Potential engine usage areas and configurations have

also been explored.• Engine seems to behave as perfect mixture air filling

engine. There is a potential area to explore if ports are re-designed to avoid short-circuit: perfect displacement is compulsory.

33

Conclusions

• Obtained NSFC in the optimum and pursued operative area, is about 204 to 214 g/kWh. In this area, the engine can provide with 30-40 kW (Always in net terms).

• Lean combustion has been explored. Potential area of 30kW gives back a BSFC 195 g/kWh. However, operative area in terms of power target, is deeply reduced (not big issue if range extender is the application).

34

Future work• How do mechanical losses behave?• How to achieve the desired P2/P3?

– Twin entry turbocharger.– Volumetric compressor (direct impact on

power and efficiency).– Other VCR configuration (more engine

compression ratio)– Strategies to rise T3 (VCR, combustion):

More boost coming from TC and less demand on volumetric compressor.

35

Testing and modelling of a 2 power strokes per revolution opposed piston engine with an

innovative kinematics

José R. Serrano1, Héctor Climent1, J. Javier López1, Alejandro Gómez-Vilanova1, Juan Garrido-Requena2, Manuel J. Luna-Blanca2 and F. Javier Contreras-Anguita2

(1)Universitat Politècnica de València. CMT-Motores Térmicos(2)INNEngine

36

Apex

Patent: EP 3 066 312 B1

Descriptive video:https://www.youtube.com/watch?v=aovQguKPG4A

INNEngine web:http://innengine.com/

https://www.youtube.com/watch?v=aovQguKPG4A



http://innengine.com/

testing and modelling of a 2 power strokes per revolution

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