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High Efficiency Combustion

Engines – What is the limit?

Prof. Bengt Johansson

Lund University

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

Today

100.0% of all cars and trucks have

internal combustion engines

The total fleet is about 1.000.000.000 cars and trucks

The electric fleet is less an 1.000.000 i.e. 0.1%

“Prediction is very difficult especially if it is about the future”- Niels Bohr http://wattsupwiththat.com/2014/07/27/prediction-is-very-difficult-especially-about-the-future/

Newsweek April 28, 1975

5

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

Per Gillbrand

Car of the future 1950-60: Gas turbine

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

1960 .................60,000 - 300,000 cars

1965 ................264,000 - 3,900,000

1970 .............11,500,000 - 42,500,000

1975 .............48,000,000 - 62,000,000 http://fuel-efficient-vehicles.org/energy-news/?page_id=943

Car of the future 1970: Stirling

Car of the future 1980: ….

Car of the future 1990: Battery Electric

GM EV-1

Car of the future 2000: Fuel Cell

Car of the future 2000: Fuel Cell

It is generally accepted that fuel cell vehicle production will follow a timeline as follows:

Starting in 2002-4:

• First production FCVs tested on public roads in US, Europe and Japan in demonstration fleets.

Around 2006-2007

• 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 http://www.engr.uconn.edu/~jmfent/AutoCompaniesonFuelCells.pdf

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 2020.

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.

Car of the future 2010: Battery Electric

Reuters news flash Sept 14 2014:

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.

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

16

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

17

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

18

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

19

Electric Vehicle – Storage capacity

900

800

700

600

500

ZMP

Ag-Zn

400

Li-Ion

300

200

Ni-

MH

200 years

Ni-

Cd 100 Lead-

Acid

0

0 50 100 150 200 250

Specific Energy (Wh/kg)

Even a low efficient ICE will have a better energy density and specific energy under normal running conditions.

300

For the same rated power an electric vehicle is much heavier than a ICE.

Cost of batteries!

350

Energy density increased 1 order of magnitude

Specific energy increased a factor of 4-5

Source: Tarascon and D. Foster Keynote speech at ASME ICES 2009

20 20

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 www.cameco.com

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

Car of the future, today

• Smaller car with small ICE in combination with hybrid system. Fuel consumption of 0.67-1 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

Car of the future, in the future

Car of the future, the Crystal Ball?

German architect André Broessel of Rawlemon

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

Energy flow in an IC engine

Brake

Combustion

*

Thermodyna mic

*

GasExchang e

*

Mechanical

+ Clean with 3-way

Catalyst

- Poor low & part load efficiency

Combustion modes

Spark Ignition (SI) engine (Gasoline, Otto)

+ High efficiency

- Emissions of NO x soot and

Compression Ignition

(CI) engine (Diesel)

+ High efficiency

+ Ultra low NO x

Homogeneous Charge

Compression Ignition

(HCCI)

-Combustion control

-Power density

Spark Assisted

Compression Ignition

(SACI)

Gasoline HCCI

+ Injection controlled

- Less emissions advantage

Partially premixed combustion (PPC)

Diesel HCCI

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

1990 1995 2000 2005 2010 2015

29

Emission focus vs. time

1970 1980 1990 2000 2010 2020

30

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

31

SAE2006-01-0205

All four efficiencies

SAE keynote Kyoto 2007

32

Net indicated efficiency= η

C

η

T

η

GE

+100%

SI std

SI high

HCCI

VCR

Scania

Brake efficiency

SI std

SI high

HCCI

VCR

Scania

Net indicated efficiency= η

C

η

T

η

GE

47%

SI std

SI high

HCCI

VCR

Scania

45

40

35

30

25

20

0

60

55

50

PPC - Diesel engine running on gasoline

HCCI: η i

=47% => PPC: η i

=57%

Group 3, 1300 [rpm]

2

FR47333CVX

FR47334CVX

FR47336CVX

4 6 8

Gross IMEP [bar]

10 12 14

36

Partially Premixed Combustion, PPC

Spridare 8x0.12x90 & 8x0.12x150, Iso-oktan, CR-tryck 750 bar, Duration 0,6 ms = 3.6 CAD

6000 1200

HCCI

PCCI CI

5000 PPC 1000

4000 800

3000

2000

1000

600

400

200

-180 -160 -140 -120 -100 -80

SOI [ATDC]

Def: region between truly homogeneous combustion, HCCI, and diffusion controlled combustion, diesel

37

SAE 2004-01-2990

Experimental setup, Scania D12

Bosch Common Rail

Prail max

Orifices

Orifice Diameter

Umbrella Angle

1600 [bar]

8 [-]

0.18

[mm]

120 [deg]

Engine / Dyno Spec

BMEPmax

Vd

Swirl ratio

15 [bar]

1951 [cm3]

2.9

[-]

Fuel: Gasoline or Ethanol

38

SAE 2009-01-2668

Efficiencies 17.1:1

39

100

95

90

85

80

75

70

65

60

55

50

4 5 6

Combustion Efficiency

Thermal Efficiency

Gas Exchange Efficiency

Mechanical Efficiency

7 8 9

Gross IMEP [bar]

10 11 12 13

39

SAE 2009-01-2668

Efficiencies 14.3:1

40

75

70

65

60

55

50

4

100

95

90

85

80

6

Combustion Efficiency

Thermal Efficiency

Gas Exchange Efficiency

Mechanical Efficiency

8 10 12

Gross IMEP [bar]

14 16 18

40

SAE 2010-01-0871

Emissions

0.6

0.3

0.2

0.1

0

2

0.6

0.5

0.4

0.3

1.5

Gross

Net

Brake

EU VI

US 10

4 6 8 10 12

Gross IMEP [bar]

14 16 18

1.2

Gross

Net

Brake

EU VI

US 10

0.9

0

2 4 6 8 10 12

Gross IMEP [bar]

14 16 18

41

10

9

8

7

6

5

1

0

2

4

3

2

1.2

1

0.8

0.6

0.4

0.2

2

1.8

1.6

1.4

0

4

Better tuned EGR-

 combination

6 8 10 12

Gross IMEP [bar]

4 6 8

41

10 12

Gross IMEP [bar]

14

14

16

Gross

Net

Brake

EU VI

US 10

16

18

18

12

10

8

6

4

2

0.3

0.25

0.2

0.15

0.1

0.05

0.5

0.45

0.4

0.35

0

2 4 6

Emissions – different fuels

Ethanol

FR47330CVX

FR47331CVX

FR47333CVX

FR47334CVX

FR47335CVX

FR47336CVX

FR47338CVX

8 10 12

Gross IMEP [bar]

14 16 18 20

2.5

2

1.5

1

0.5

Ethanol

FR47330CVX

FR47331CVX

FR47333CVX

FR47334CVX

FR47335CVX

FR47336CVX

FR47338CVX

0

2

SAE 2010-01-0871

4

Ethanol

FR47330CVX

FR47331CVX

FR47333CVX

FR47334CVX

FR47335CVX

FR47336CVX

FR47338CVX

6 8 10 12

Gross IMEP [bar]

14 16 18 20

0

2 4 6 8 10 12

Gross IMEP [bar]

14 16 18 20

5

4

3

2

1

0

2

10

9

8

7

6

4 6 8 10

42

12

Gross IMEP [bar]

14

Ethanol

FR47330CVX

FR47331CVX

FR47333CVX

FR47334CVX

FR47335CVX

FR47336CVX

FR47338CVX

16 18 20

20

15

Tested Load Area

25

Stable operational load vs. fuel type

10

5

0

20 30 40 50 60

RON [-]

70 80 90 100

43

Efficiency with Diesel or Gasoline

Average improvement of 16.6% points at high load by replacing diesel fuel with gasoline!

52

50

D13 Gasoline

D13 Diesel

48

46

44

42

40

38

36

34

5 10 15 20

Gross IMEP [bar]

25

D13 Diesel was calibrated by Scania to meet EU V legislation.

30

44

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

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

1990 1995 2000 2005 2010 2015

46

Energy flow in an IC engine

Brake

Combustion

*

✔ mic

*

✖ e

*

High efficiency thermodynamics:

Simulation results from GT-power

• Indicated efficiency 64%

• Brake efficiency 60.4%

• System layout is confidential

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

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

Future

• Optimize the combustion process

– PPC

– Diesel

– Spark Ignition (prechamber)

• Improve the thermodynamics

– A compression ratio,R h

(γ=1.38) gives a thermodynamic efficiency of 80%! c

T

=

1 of 70:1 and lean mixture

-

• Work with engine systems, not only details

1

R c g -

1

51

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

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

Thank you!

54

High Efficiency Combustion

Engines – What is the limit?

Prof. Bengt Johansson

Lund University

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