Potential of Modern Internal Combustion Engines – Review ... Engine Potential.pdf · Potential of...

Center for Diesel Research

Potential of Modern Internal Combustion Engines – Review of

Recent trendsDavid Kittelson

Center for Diesel Research Department of Mechanical Engineering

University of Minnesota

February 15, 2011


Outline

• Background– Current engine types– Fuel economy standards– Emission standards– New combustion modes

• Trends in new engine design• Projected engine and vehicle performance

trends• Fundamental research programs• Conclusions


Thermal efficiency of modern engines

• Thermal efficiency is defined as:

• It ranges from zero at idle to a maximum value at high load and moderate speed

– Spark ignition gasoline engine with 3-way catalyst ~ up to mid 30% range

– Passenger car Diesel ~ up low 40% range

– Heavy-duty truck Diesel ~ up to high 40% range

– Large (very) marine Diesel like that shown on right ~ 50%

– DOE target heavy-duty “SuperTruck” goal – 55%

• Stringent emission standards must be met

InputFuelEnergyWorkOuputiciencyThermalEff =


2009

Source: Annual Energy Outlook 2011, U.S. Energy Information Administration

Transportation constitutes 28% of U.S. energy consumption 94% of it comes from petroleum – 74% of petroleum use

More than 50% of this is imported


0

4

8

12

16

1995 2000 2005 2010 2015 2020 2025 2030 2035

Most transport fuel growth is in light and heavy duty vehicles

U.S. transportation energy consumptionmillion barrels per day oil equivalent

Rail

Air

ProjectionsHistory

Heavy-duty vehicles

Light-duty vehicles

Marine

2009

4%

67%

2%

10%

16%

64%

20%

9%4%2%

Source: Annual Energy Outlook 2011, U.S. Energy Information Administration


Historical fleet fuel economy performance and current or proposed standards

Source: Global Comparison of Light-Duty Vehicle Fuel Economy/GHG Emissions Standards - http://www.theicct.org/passenger-vehicles/global-pv-standards-update/


Historical fleet CO2 emissions performance and current or proposed standards

Source: Global Comparison of Light-Duty Vehicle Fuel Economy/GHG Emissions Standards - http://www.theicct.org/passenger-vehicles/global-pv-standards-update/


We need to meet the challenge of increased efficiency while meeting ever tighter emission standards

2014 2015 2016 2017 2018 2019 2020 2021 2022

S1

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Flee

t Ave

rage

NO

x +

NM

OG

(g/m

i)Model Year

Proposed CA light-duty vehicle emission standards

Heavy-Duty Light-Duty

Source: Heavy Duty Diesels –The Road Ahead, Elmar Boeckenhoff, US DOE DEER conference 2010

Source:http://www.arb.ca.gov/msprog/levprog/leviii/meetings/111610 /draft_sftp2_regs_nov2010.pdf


Quick review of current engine types

Source: Diesel Power: Clean Vehicles for the Future - https://www1.eere.energy.gov/informationcenter/


A new direction in engines – Low temperature combustion

• Diesel– Diffusion burning of fuel jet– High efficiency

• High compression ratio• Lean combustion• Very high combustion efficiency > 99%• No throttle

– Low hydrocarbon and CO emissions– Soot and NOx must be controlled by

expensive exhaust aftertreament• Diesel particle filter• NOx control by SCR or lean NOx trap• Fuel economy penalty

• Spark ignition– Usually premixed – Moderate efficiency

• Moderate compression ratio to avoid knock

• Chemically correct combustion• Poor light load efficiency due to

throttling• Moderate combustion efficiency ~ 90%

– High hydrocarbon, CO, and NOx emissions, low soot emissions

– Hydrocarbon, CO, and NOx emissions easily controlled by relatively inexpensive 3-way catalyst

How do we get the high efficiency of a Diesel engine without high NOx and soot emissions that require expensive exhaust aftertreament?

A new combustion mode – low temperature combustion (LTC)

There are many flavors of LTC including, for example, homogeneous charge compression ignition (HCCI), partially premixed combustion (PPC), reaction controlled compression ignition (RCCI) and alphabet soup.

Center for Diesel ResearchFrom: Numerical and Experimental Studies of HCCI combustion, Salvador Aceves, et al., Sixth Diesel Engine Emissions Reduction Workshop August, 2000.


Diesel, spark ignition, and LTC follow different paths during combustion

• Diesel– Fuel rich region initially

surrounds each droplet as fuel evaporates

– At roughly φ = 3 -4 diffusion burning starts

– Mixing path passes through soot formation and NOx formation regions

• Spark ignition– Premixed combustion take

place at near φ = 1– Very high NOx, CO and HC

• HCCI– Premixed conditions avoid both

soot and NOx islands– However bulk and wall

quenching lead to high CO and HC emissions

1000 1400 1800 2200 2600 3000Temperature (K)

SI Region

LTC Region

6

5

4

3

2

1

Typical Diesel Droplet Combustion Path

Kitamura et al (2002)

Φ


Outline





GM gasoline engine improvement plans

Source: Advanced Propulsion Technology Strategy, Tom Stephens, 2010 DOE DEER Conference


GM Diesel engine improvement plans

Source: Advanced Propulsion Technology Strategy, Tom Stephens, 2010 DOE DEER Conference


VW engine improvement plans

Source: Future Directions in Engines and Fuels, Stuart Johnson, 2010 DOE DEER Conference


Cummins heavy-duty Diesel engine improvement plans

Source: High Efficient Clean Combustion for SuperTruck, Donald Stanton, USDOE DEER 2009 conference


Cummins is exploring organic Rankine bottoming cycles

Source: Exhaust Energy Recovery, Chris Nelson, USDOE DEER 2009 conference


Diesel and spark ignition engines are on converging paths – toward LTC• Spark Ignition

– Direct injection– Turbo-supercharging– Downsizing– Variable valve lift and timing– Displacement management– Adaptive control with

advanced sensors– Reduced friction– LTC modes, HCCI, PCCI, etc.

• Diesel– Higher levels of turbo-

supercharging – two stage– Even higher injection

pressure, multiple injections– Variable valve timing– Adaptive control with

advanced sensors– Reduced friction– Advanced aftertreatment– Downsizing– Waste heat recovery

• Turbocompound• Organic Rankine• Thermoelectric

– LTC modes, HCCI, PCCI, etc.


Outline





Predicted trends in U.S. passenger car consumption

Source: L. Cheah,J.Heywood/EnergyPolicy39(2011)454–466

By 2030 hybrid gasoline electric vehicles will consume roughly 1/3 the fuel of a current conventional vehicle


One projection by CARB of what will be necessary to reduce passenger car CO2 emissions in California by 80% in 2050

In 2040 we will still as many vehicles relying on engines as today

Source: The Path to Low Carbon Passenger Vehicles, Tom Cackette, USDOE DEER 2010 conference


Cummins projected heavy-duty engine efficiencies

Source: High Efficient Clean Combustion for SuperTruck, Donald Stanton, USDOE DEER 2010 conference


Outline





Engine combustion – direction – Lund University, Sweden

Source: Path to High Efficiency Gasoline Engine, Bengt Johansson, 2010 DOE DEER Conference


Scania D13 running on diesel and gasoline

Source: Path to High Efficiency Gasoline Engine, Bengt Johansson, 2010 DOE DEER Conference

Operating a Diesel engine with very early injection timing and low octane gasoline allows it to operate in a LTC mode


Outline





Conclusions

• Engines promise to be around for many years• The need to reduce consumption while producing near

zero emissions has spurred innovation• Diesel and spark ignition engines are on a converging

path, low temperature combustion modes are likely for both engine types

• By 2030 gasoline electric hybrid vehicles are projected to deliver roughly three times the fuel economy of today’s conventional gasoline vehicles

• Thermal efficiencies will continue to increase– Approaching 50% for light-duty engines– Approaching 60% for heavy-duty engines


Is there a quicker path to high mileage? Today’s engine and driveline in a vehicle with 1985 acceleration and size would get 39 MPG, a 56% improvement!

PSFI = P.S.F.I = (hp/lb).ft3.MPG

Source: L. Cheah,J.Heywood/EnergyPolicy39(2011)454–466


Ongoing research• Low temperature combustion of producer gas (DOE, IREE, DOD)

– From a biomass gasifier– From a catalytic reformer

• Dimethyl ether, a second generation renewable diesel fuel (IREE, GM)– Life cycle GHG and economic analysis– Performance and emission measurement– Fuel handling and injection system development

• Development of an integrated powertrain research facility (NSF)• Development of combined diesel particle filter and lean NOx trap

(Dow Chemical)• Solid particle measurement systems (AVL)• Miniature free piston HCCI engine compressor (CCEFP-NSF)


Questions?

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