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

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Presentation on theme: "High Efficiency Combustion Engines – What is the limit? Prof. Bengt Johansson Lund University."— Presentation transcript:

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

2 Outline Introduction 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 Today 100.0% of all cars and trucks have internal combustion engines 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 5 Newsweek April 28, 1975

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

7 Car of the future : Gas turbine

8 “Timetable for Next Car Engine : The Gas Turbine and Its Future” Business Week, April 2, 1955, page 134+ THEY ESTIMATE by , ,000 cars , ,900, ,500, ,500, ,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 “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 16 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 2014Håkan Abrahamson, Ny teknik 10 juli 2014

17 Toyota: Elbilen behöver Nobelprisbatteri 17 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.

18 Battery performance 18 Source: Private communications with Prabhakar Patil, CEO, LG Chem, Battery Div. Nov. 4, 2011 “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”

19 Li-ion battery performance is now at 52% of theoretical limit 19 Source: Private communications with Prabhakar Patil, CEO, LG Chem, Battery Div. Nov. 3, /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, /790=0, /459=0, /385=0,519

20 20 Electric Vehicle – Storage capacity 200 years Energy density increased 1 order of magnitude Specific energy increased a factor of 4-5 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! Source: Tarascon and D. Foster Keynote speech at ASME ICES 2009

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

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 22

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 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 Spark Ignition (SI) engine (Gasoline, Otto) Compression Ignition (CI) engine (Diesel) Homogeneous Charge Compression Ignition (HCCI) Partially premixed combustion (PPC) Diesel HCCI Spark Assisted Compression Ignition (SACI) Gasoline HCCI + High efficiency + Ultra low NO x -Combustion control -Power density +Clean with 3-way Catalyst -Poor low & part load efficiency +High efficiency -Emissions of NO x and soot +Injection controlled - Less emissions advantage

29 ICE research in Lund vs. time 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

30 Emission focus vs. time

31 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 32 SAE keynote Kyoto 2007

33 Net indicated efficiency= η C η T η GE SI std SI high HCCI VCR Scania +100%

34 Brake efficiency SI std SI high HCCI VCR Scania

35 Net indicated efficiency= η C η T η GE SI std SI high HCCI VCR Scania 47%

36 PPC - Diesel engine running on gasoline HCCI: η i =47% => PPC: η i =57% 36

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

38 38 Experimental setup, Scania D12 Bosch Common Rail Prail max 1600[bar] Orifices8[-] Orifice Diameter0.18[mm] Umbrella Angle120[deg] Engine / Dyno Spec BMEPmax15[bar] Vd1951[cm3] Swirl ratio2.9[-] Fuel: Gasoline or Ethanol SAE

39 39 Efficiencies 17.1:1 SAE

40 Gross IMEP [bar] [%] Combustion Efficiency Thermal Efficiency Gas Exchange Efficiency Mechanical Efficiency Efficiencies 14.3:1 SAE

41 41 Emissions Better tuned EGR- combination

42 42 Emissions – different fuels SAE

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

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

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 45

46 ICE research in Lund vs. time 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

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 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 50

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

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. 52

53 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! 54

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


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