1. High Efficiency Combustion Engines – What is the limit?
Prof. Bengt Johansson
Lund University

2. Outline Introduction Combustion engines Conclusions
The future is hard to predict
Options
Other combustion engines?
Fuel cells?
Batteries?
Combustion engines
What is high efficiency?
Combustion, thermodynamic, gas exchange and mechanical efficiencies. All four must be high.
What options do we have?
Combustion to enable high efficiency
Spark Ignition
Compression Ignition
HCCI
Partially Premixed Combustion
Can we do something about engine design?
Conclusions

3. 100.0% internal combustion engines Today of all cars and trucks have
The total fleet is about cars and trucks
The electric fleet is less an i.e. 0.1%

4. “Prediction is very difficult especially if it is about the future”- Niels Bohr

5. Newsweek April 28, 1975

6. ”Den som ser framåt utan att se bakåt får se upp” - Per Gillbrand

7. Car of the future 1950-60: Gas turbine

8. Car of the future 1950-60: Gas turbine
“Timetable for Next Car Engine : The Gas Turbine and Its Future” Business Week, April 2, 1955, page 134+
THEY ESTIMATE by
, ,000 cars
, ,900,000
,500, ,500,000
,000, ,000,000

9. Car of the future 1970: Stirling

10. Car of the future 1980: ….

11. Car of the future 1990: Battery Electric
GM EV-1

12. Car of the future 2000: Fuel Cell

13. Car of the future 2000: Fuel Cell
“It is generally accepted that fuel cell vehicle production will follow a timeline as follows:
Starting in :
• First production FCVs tested on public roads in US, Europe and Japan in demonstration fleets.
Around
• Second generation fuel cell systems incorporated into FCVs and the expansion of FCV fleets in the US, Europe and Japan.
Starting in 2010
• Marketing of commercially viable FCVs at affordable prices - this will be the first step toward ultimately replacing the conventional internal combustion engine models.”
August 29, 2002, Bloomberg News :
”Larry Burns, GM’s vice-president for R&D: “GM’s goal is to be the world’s first company to produce one million fuel cell vehicles a year,” and that GM is looking to sell hundreds of thousands of fuel cell vehicles between 2010 and 2020

14. Car of the future 2010: Battery Electric
Carlos Ghosn CEO Renault/Nissan 2010: “Nissan Will Sell 500,000 Electric Cars a Year by 2013”
He predicted that 10 percent of the world car market would be electric vehicles by “There is no doubt in the minds of anyone in the industry that this is going to be a big factor in the industry,” he said.

15. Car of the future 2010: Battery Electric
Reuters news flash Sept :
Nissan faces battery plant cuts as electric car hopes fade
Ghosn dropped extra battery sites planned for both alliance carmakers, leaving Nissan with the entire production capacity of 220,000 power packs through the NEC joint venture, AESC.
But that still far exceeds the 67,000 electric cars Renault-Nissan sold last year, and even the 176,000 registered to date. A pledge to reach 1.5 million by 2016 has been scrapped.

16. Toyota: Elbilen behöver Nobelprisbatteri
Tekniken som behövs för att göra elbilar användbara är inte uppfunnen än
Körsträckan är så kort med en elbil, och laddtiden är så lång, summerar Kato. Med den tekniknivå vi befinner oss på i dag behöver någon uppfinna ett batteri så bra att det vinner Nobelpris.
För att kunna konkurrera med dagens bensindrivna bilar behövs så mycket batterier att det ökar kostnaderna och laddtiderna.
- Antalet kunder som är nöjda med elbilens korta räckvidd är begränsad, säger han. Men blir intresset för sådana bilar plötsligt större, då är vi beredda att leverera.
Av: Håkan Abrahamson, Ny teknik 10 juli 2014

17. Toyota: Elbilen behöver Nobelprisbatteri
I en intervju i Automotive News ger han tummen ner för satsningen på elbilar, och säger att Toyota nu lägger sin tillverkning av elbilar.
Företaget tror att alternativet till bensin och diesel heter vätgas. Nästa år lanserar Toyota en bränslecellbil, och även andra tillverkare ligger startgroparna med den sortens drivning.
Vid det laget erbjuder Toyota inte längre någon helt eldriven bil, säger Kato. De små serier av elbilar som nu finns på programmet, minibilen eQ och RAV4 EV, läggs ner i slutet av det här året.
Av: Håkan Abrahamson, Ny teknik 10 juli 2014 


18. Battery performance
“The active material for the anode and the cathode which are assumed to be a carbon-based anode (~2.7 g/Ah) and a Co-based cathode (~7.3 g /Ah) for the Li-ion cell. The specific capacity of the couple is therefore ~100 Ah/kg which combined with the  voltage of 3.85 V for this couple leads to the 385 Wh/kg number”
Source: Private communications with Prabhakar Patil, CEO, LG Chem, Battery Div. Nov. 4, 2011

19. Li-ion battery performance is now at 52% of theoretical limit
40/250=0,160
55/245=0,225
55/315=0,175
70/370=0,189
80/240=0,333
20/810=0,025
20/135=0,148
70/570=0,123
180/790=0,228
130/459=0,283
200/385=0,519
Source: Private communications with Prabhakar Patil, CEO, LG Chem, Battery Div. Nov. 3, 2011

20. Electric Vehicle – Storage capacity
Energy density increased 1 order of magnitude
Specific energy increased a factor of 4-5
200 years
Even a low efficient ICE will have a better energy density and specific energy under normal running conditions.
For the same rated power an electric vehicle is much heavier than a ICE.
Cost of batteries! 20
Source: Tarascon and D. Foster Keynote speech at ASME ICES 2009

21. Electric Vehicle – Electricity source?
Q: What is the similarity of a steam engine and a battery electric vehicle?
A: They both run on coal… 21

22. Summary on alternatives
They have all promised much but delivered little!
There is today not a viable alternative to the Internal Combustion Engine
We must focus our little resources to improve what will be the prime mover of the future, not unrealistic scenarios
The ICE can be improved very much in the future

23. Car of the future, today
Smaller car with small ICE in combination with hybrid system. Fuel consumption of l/100km (<25 g/km CO2)
ICE 60% fuel efficient with below zero levels of local emissions like NOx, PM, HC and CO. The 40% heat loss is used for heating the car.
At least 100% CO2-neutral with renewable fuel

24. Car of the future, in the future?

25. Car of the future, the Crystal Ball?
German architect André Broessel of Rawlemon

26. Outline Introduction Combustion engines Conclusions
The future is hard to predict
Options
Other combustion engines?
Fuel cells?
Batteries?
Combustion engines
What is high efficiency?
Combustion, thermodynamic, gas exchange and mechanical efficiencies. All four must be high.
What options do we have?
Combustion to enable high efficiency
Spark Ignition
Compression Ignition
HCCI
Partially Premixed Combustion
Can we do something about engine design?
Conclusions

27. Energy flow in an IC engine

28. Combustion modes + Clean with 3-way Catalyst
- Poor low & part load efficiency
+ High efficiency
- Emissions of NOx and soot
Combustion modes
Spark Ignition (SI) engine (Gasoline, Otto)
Compression Ignition (CI) engine (Diesel)
+ High efficiency
+ Ultra low NOx
Combustion control
Power density
Homogeneous Charge Compression Ignition (HCCI)
Spark Assisted Compression Ignition (SACI) Gasoline HCCI
Partially premixed combustion (PPC) Diesel HCCI
+ Injection controlled
- Less emissions advantage

29. ICE research in Lund vs. time
High eff. themodynamics
PPC
CCV=Cycle to Cycle Variations in Spark Ignition Engines
GDI= Gasoline Direct Injection
2-S= Two Stroke engine
VVT=Variable Valve Timing
HCCI=Homogeneous Charge Compression Ignition
SACI=Spark Assisted Compression Ignition
PPC= Partially Premixed Combustion
HCCI
SACI
VVT
2-S
GDI
GenDiesel
CCV
Si gas engine
Si gas engine
1990
1995
2000
2005
2010
2015

30. Emission focus vs. time SOx Particulates NOx CO CO2 HC 1970 1980 1990
2000
2010
2020

31. HCCI -Thermodynamic efficiency
Saab SVC variable compression ratio, VCR, HCCI, Rc=10:1-30:1;
General Motors L850 “World engine”, HCCI, Rc=18:1, SI, Rc=18:1, SI, Rc=9.5:1 (std)
Scania D12 Heavy duty diesel engine, HCCI, Rc=18:1;
Fuel: US regular Gasoline
SAE

32. All four efficiencies
SAE keynote Kyoto 2007

33. Net indicated efficiency= ηC ηT ηGE
SI std
SI high
HCCI
+100%
VCR
Scania

34. Brake efficiency
SI std
SI high
HCCI
VCR
Scania

35. Net indicated efficiency= ηC ηT ηGE
47%
SI std
SI high
HCCI
VCR
Scania

36. PPC - Diesel engine running on gasoline
HCCI: ηi=47% => PPC: ηi=57%

37. Partially Premixed Combustion, PPC
PCCI CI
HCCI
PPC
Def: region between truly homogeneous combustion, HCCI, and diffusion controlled combustion, diesel
SAE

38. Experimental setup, Scania D12
Bosch Common Rail
Prailmax
1600
[bar]
Orifices 8
[-]
Orifice Diameter
0.18
[mm]
Umbrella Angle
120
[deg]
Engine / Dyno Spec
BMEPmax 15 Vd
1951
[cm3]
Swirl ratio
2.9
Fuel: Gasoline or Ethanol 38 38
SAE

39. Efficiencies 17.1:1 39
SAE

40. Efficiencies 14.3:1 40 100 95 90 85 80 Combustion Efficiency [%] 75
Thermal Efficiency 70
Gas Exchange Efficiency
Mechanical Efficiency 65 60 55 50 4 6 8 10 12 14 16 18
Gross IMEP [bar] 40
SAE

41. Emissions
Better tuned EGR- combination 41

42. Emissions – different fuels
SAE

43. Stable operational load vs. fuel type
Tested Load Area
Stable operational load vs. fuel type 43 43

44. Efficiency with Diesel or Gasoline
Average improvement of 16.6% points at high load by replacing diesel fuel with gasoline!
D13 Diesel was calibrated by Scania to meet EU V legislation.

45. PPC Combustion Summary
PPC has shown very high fuel efficiency
Indicated efficiency of 57% at 8 bar IMEP
Indicated efficiency of 55% from 5-18 bar IMEP
With 70 RON fuel we can operate all the way from idle to 26 bar IMEP
Emissions are below US10/Euro 6 without aftertreatment for NOx, PM, HC and CO!
The fuel properties are critical for PPC load range

46. ICE research in Lund vs. time
High eff. themodynamics
PPC
CCV=Cycle to Cycle Variations in Spark Ignition Engines
GDI= Gasoline Direct Injection
2-S= Two Stroke engine
VVT=Variable Valve Timing
HCCI=Homogeneous Charge Compression Ignition
SACI=Spark Assisted Compression Ignition
PPC= Partially Premixed Combustion
HCCI
SACI
VVT
2-S
GDI
GenDiesel
CCV
Si gas engine
Si gas engine
1990
1995
2000
2005
2010
2015

47. Energy flow in an IC engine✔ ✔ ✖ ✖

48. High efficiency thermodynamics: Simulation results from GT-power
Indicated efficiency 64%
Brake efficiency 60.4%
System layout is confidential

49. Outline Introduction Combustion engines Conclusions
The future is hard to predict
Options
Other combustion engines?
Fuel cells?
Batteries?
Combustion engines
What is high efficiency?
Combustion, thermodynamic, gas exchange and mechanical efficiencies. All four must be high.
What options do we have?
Combustion to enable high efficiency
Spark Ignition
Compression Ignition
HCCI
Partially Premixed Combustion
Can we do something about engine design?
Conclusions

50. The future ICE Highest possible fuel efficiency
Low enough emissions of NOx, PM, HC, CO
Capable of using renewable fuels
And the basic requirements of all products:
Very high durability
Low service requirements
High power/mass ratio
High power/volume ratio
Low cost

51. Future Optimize the combustion process Improve the thermodynamics
PPC
Diesel
Spark Ignition (prechamber)
Improve the thermodynamics
A compression ratio,Rc of 70:1 and lean mixture (γ=1.38) gives a thermodynamic efficiency of 80%!
Work with engine systems, not only details

52. What is the long term future?
Active rate shaping
What is the best Rate of Heat Release, RoHR, for maximum thermodynamic efficiency?
The analog fuel injector with real time control of fuel flow and hence RoHR (with short ignition delay) using FPGA
Fuels and engine interactions
Best fuel for a combustion process
Fuel flexible combustion process
Natural gas/Biogas
LNG/LBG-intercooler
Hybrids
The 2, 4, 6 concept
Air Hybrid
Heat transfer, coatings etc.

53. Prof. Bengt Johansson Lund University
High Efficiency Combustion Engines – What is the limit? “It all starts at 40 and ends at 60” ( %engine efficiency that is, not life)
Prof. Bengt Johansson
Lund University

54. Thank you!

55. High Efficiency Combustion Engines – What is the limit?
Prof. Bengt Johansson
Lund University