Technology and Economic Analysis in the Prepublication Version of the Report 'Effectiveness and Impact of Corporate Average Fuel Economy (CAFE) Standards': Letter Report (2002)

Technology Description

Vehicle fuel consumption reduction resulting from reduced engine friction

Primary Benefits

Higher brake mean effective pressure (BMEP) for the same indicated mean effective pressure (IMEP)

Secondary Benefits

Higher BMEP allows engine downsizing.

FC Improvement

Base: 2V baseline engine; Reference: 2V baseline engine

1 ~ 5%

1 ~ 5%

Example of Application

General technology to improve engine efficiency

Reference

FEV, M.Schwaderlapp, F.Koch, J.Dohmen

Fisita 2000–3, Seoul Congress

Conclusions: In the next 10 years it will be possible to reduce SI engine fuel consumption by 8–13% through friction reduction

8–13%

Technology Description

Low friction lubricant to reduce engine friction and driveline parasitic losses.

Primary Benefits

Low engine friction to reduce vehicle fuel consumption

Secondary Benefits

Low friction to reduce driveline parasitic losses and vehicle fuel consumption

FC Improvement

Base: 2V baseline engine; Reference: 2V baseline engine

1.0%

1.0%

Example of Application

Reference

Toyota/Nippon Oil: K.Aklyama, T.Ashida; K.Inoue, E.Tominaga

SAE-Paper 951037

Conclusion: Using additive in the lubricant oil reduces the fuel consumption by 2.7% for a 4.0L-V8–4V engine

2.7 %

Technology Description

Improvement from 2 valve engine into a multiintake valve engine (including total of 3, 4, and 5 valves per cylinder)

Primary Benefits

Lower pumping losses: larger gas exchange flow area Less friction: higher mechanic efficiency due to higher engine IMEP

Secondary Benefits

Less pumping losses: engine down size with higher power density Higher thermal efficiency: higher compression ratio due to less knocking tendency and faster combustion process with central spark plug position

FC Improvement

Base: 2V baseline engine; Reference: 2V baseline engine

2 ~ 5%

2 ~ 5%

Example of Application

Advanced engines from Ford, GM, and DC

Reference

Volkswagen: R.Szengel, H.Endres

6. Aachener Kolloquium (1997)

Conclusion: A1.4L-I4–4V engine improves the fuel consumption by 11% (MVEG) in comparison to a 1.6L-I4–2V engine

11% FC in MVEG

Ford: D.Graham, S.Gerlach, J.Meurer. SAE-Paper 962234

Conclusion: new valve train design (from OHV to SOHC) with 2 valves per cylinder plus additional changes (higher CR, less valve train moving mass) result in a 28% increase in power, 11% increase in torque and 4.5% reduction in fuel consumption (11.2 to 10.7 L/100km, M-H) for a 4.0L-V6–2V engine.

4.5% FC (OHV, 2V to SOHC, 2V) +28% power +11% torque

Sloan Automotive Laboratory/MIT: Dale Chon, John Heywood SAE-Paper 2000–01–0565

Conclusion: The changing preference from 2-valve to 4-valve per-cylinder is a major factor of current engine power and efficiency improvement; the emergence of variable valve timing engines suggests a possible new trend will emerge.

Technology Description

Variable valve timing in the limited range through cam phase control

Primary Benefits

Less pumping losses: later IVC to reduce intake throttle restriction for the same load

Secondary Benefits

Less pumping losses: down size due to better torque compatibility at high and low engine speed for the same vehicle performance

FC Improvement

Base: 2V baseline engine; Reference: 4V OHC engine

4 ~ 8%

2 ~ 3%

Example of Application

Toyota VVT-i; BMW Vanos

Reference

Ford: R.A.Stein, K.M.Galietti, T.G.Leone SAE-Paper 950975

Conclusion: for a 4.6L-V8–2V engine in a 4,000 Ib vehicle benefit in M-H fuel consumption of 3.2% with unconstrained cam retard and 2.8% (M-H) with constrained cam retard (10% EGR)

2.8 ~ 3.2% V8, 2V engine

Ford: T.G.Leone, E.J.Christenson, R.A.Stein SAE-Paper 960584

Conclusion: for a 2.0L-I4–4V engine in a 3,125 Ib vehicle benefit in M-H fuel consumption of 0.5–2.0% (10–15% EGR)

0.5–2.0% 14, 4V engine

Toyota: Y.Moriya, A.Watanabe, H Uda, H.Kawamura, M.Yoshioka, M. Adachi. SAE-Paper 960579

Conclusion: for a 3.0L-I6–4V engine the VVT-i technology (phasing of intake valves) improved the fuel consumption by 6% on the 10–15 official Japanese mode.

6% Japanese mode 16, 4V engine

Ford: D.L.Boggs, H.S.Hilbert, M.M.Schechter. SAE-Paper 950089

Conclusion: for a 1.6L-I4 engine the later intake valve closing improved the BSFC by 15% (10% EGR).

15% (BSFC) 14, Late IVC

MAZDA/Kanesaka TI: T.Goto, K.Hatamura, S.Takizawa, N.Hayama, H. Abe, H.Kanesaka. SAE-Paper 940198

Conclusion: A 2.3L-V6–4V boosted engine with a Miller cycle (late intake valve closing) has a 10–15% higher fuel efficiency compared to natural aspiration (NA) engine with same maximum torque. 25% reduction in friction loss because of lower displacement. Expected 13% increase in fuel consumption of 2.3L Miller engine compared to 3.3L NA engine.

10–15% Fuel Efficiency, Miller cycle

Mitsubishi: K.Hatano, K.lida, H.Higashi, S.Murata. SAE-Paper 930878

Conclusion: A 1.6L-I4–4V engine reached an increase in fuel efficiency up to 16% (Japanese Test Driving Cycle) and an power increase of 20%.

Up to 16% in FC 20% Power

Honda/Nissan/…: S.Shiga; S.Yagi; M.Morita; T.Matsumoto; H.Nakamura; T.Karasawa SAE-Paper 960585

Conclusion: For a 0.25L-I1–4V test engine an early closing of the intake valve results in up to 7% improvement in thermal efficiency

Up to 7% Fuel Efficiency

Ricardo: C.Gray SAE-Pager 880386

Conclusion: Variable intake valve closing and cam timing duration improves part load fuel consumption by 3–5 %

3–5% at part load

Technology Description

Valve lift and valve timing controlled according to engine load and speed, with step controlled mechanism

Primary Benefits

Less pumping losses: partially use intake valve timing and lift control for intake throttle control

Higher thermal efficiency: for better mixture formation with intake valve throttling

Secondary Benefits

Less pumping losses: engine down size with higher power density

FC Improvement

Base: 2V baseline engine; Reference: VVT engine

5 ~ 10%

1 ~ 2%

Example of Application

Honda i-VTEC; Porsche Variocam Plus; Toyota VVLT-i

Reference

Honda: M.Matsuki, K.Nakano, T.Amemiya, Y.Tanabe, D.Shimizu, I. Ohmura SAE-Paper 960583

Conclusion: for a 1.5L-I4–4V engine the 3-stages VTEC technology (three different cams) improved the power output by 40% with the same fuel consumption

40% more power with same fuel consumption

Porsche: C.Brüstle, D.Schwarzenthal. SAE-PAPER 980766

Conclusion: for a B6–4V engine the fuel consumption could be reduced by 3–9% with variable valve lift

3–9%

Meta: P.Kreuter, P.Heuser, J.Reinicke-Murmann, R.Erz, U.Peter. SAE-Paper 1999–01–0329

Conclusion: For a 2.0L-I4–4V engine the VVLT system improved the fuel efficiency by 11% to 15% in idle speed

11% to 15% at idle

Technology Description

Deactivate number of cylinders so that the active cylinders work on higher BMEP level, normally valve deactivation is necessary

Primary Benefits

The active cylinders have less pumping loss with higher BMEP level

Secondary Benefits

FC Improvement

Base: 2V baseline engine; Reference: VVTL engine

8–16%

3–6%

Example of Application

Mercedes 5.0 L V8 and 6.0 L V12

Reference

Meta: P.Kreuter, P.Heuser, J.Reinicke-Murmann, R.Erz, P.Stein, U. Peter. SAE-Paper 2001–01–0240

Conclusion: A 14 engine with cylinder valve deactivation (CVD) showed 20% improvement in fuel consumption at low engine speed. A V8 engine showed 6–8% improvement in fuel consumption for the New European Driving Cycle

6–8% FC in NEDC

Daimler-Chrysler: M.Fortnagel, G.Doll, K.Kollmann, H.-K.Weining. MTZ 98 Sonderheft

Conclusion: A 5.0L-V8-V3 engine has an improvement of 6.5% fuel consumption (New European Driving Cycle) and 10.3% in the FTP+HW cycle with the cylinder deactivation

6.5% FC in NEDC

10.3% FC in FTP+HW

Technology Description

Improving the efficiency of accessory components or their power transmission to reduce the engine energy losses

Primary Benefits

Direct reduction of vehicle fuel consumption

Secondary Benefits

Higher net output allows engine downsizing

FC Improvement

Base: 2V baseline engine; Reference: 4V OHC engine

3 ~ 7%

1 ~ 2%

Example of Application

Less coolant flow rate, less oil flow rate

Reference

“Technology and Cost of Future Fuel Economy Improvements for Light-Duty Vehicles—Draft Final Report”; Energy and Environmental Analysis, Inc.— NAS Report—June 4, 2001

Conclusions: Between 0.5 and 1% reduction in fuel economy is possible

0.5–1% reduction in fuel economy

Technology Description

Reduce the engine displacement and supercharge it for the required power

Primary Benefits

Less pumping loss at low load conditions; less friction power loss at the same FMEP; less Idle losses

Secondary Benefits

None

FC Improvement

Base: 2V baseline engine; Reference: 4V OHC engine

7 ~ 12%

5 ~ 7%

Example of Application

Reference

FEV, Peter Walzer, 00ELE028 Future Engines For Cars

Conclusions: Engine down size from 3L to 1.5L with supercharging and VCR, part load specific fuel consumption improves by 25%

25% at part load, with VCR

Technology Description

Added ratio places engine in better average speed/load operating point.

Improvements in torque converter lockup via Slip Controlled Converter Clutch.

Improved internal oil pump losses by reducing pressure.

Closed-loop shift strategy.

Reduction of gear drag losses.

General weight reduction.

Primary Benefits

Less pumping loss at low load conditions; less friction power loss at the same FMEP; lower Idle losses

Secondary Benefits

Improved transmission efficiencies

FC Improvement

Baseline: 4-speed; Reference: 4-speed

2 ~ 3%

2 ~ 3%

Example of Application

Reference

SAE- 970689, “ZF 5-Speed Transmissions for Passenger Cars”; Heribert Scherer, Georg Gierer

Auto 2000, “ZF 5-Speed Automatic Transmission”; Heribert Scherer

Conclusions: A 5% reduction can be attributed to the new 5-speed transmission

5% on combined M-H FTP-75

Technology Description

Added ratio places engine in better average speed/load operating point.

Elimination of torque converter with an optimized starting clutch procedure.

Reduced work loss in the drive train and accessories due to the gear ratio characteristics unique to the CVT

Primary Benefits

Less pumping loss at low load conditions; less friction power loss at the same FMEP; lower Idle losses

Secondary Benefits

Improved drive train and accessory losses

FC Improvement

Baseline: 4-speed, Reference: 5-speed

6 ~ 11%

4 ~ 8%

Example of Application

Audi A4—Multitronic

Reference

ATZ 8&9/2000, “Multitronic—The New Automatic Transmission from Audi— Parts 1 & 2”

SAE 970685, “ECOTRONIC—Continuously Variable ZF Transmission (CVT);” Manfred Boos and Herbert Mozer

SAE 1999–01–0754, “Development of an Engine-CVT Integrated Control System;” S.Sakaguchi, E.Kimura, K.Yamamoto

Conclusions: A 9.3% reduction can be attributed to the CVT transmission

9.3% on MVEG

Technology Descriptions

Improvements in torque converter lockup.

Closed-loop shift control strategy

Primary Benefits

Reduced transmission losses

Secondary Benefits

None

FC Improvement

Baseline: 4-speed, Reference: 5-speed

3 ~ 6%

1 ~ 3%

Example of Application

Reference

“Technology and Cost of Future Fuel Economy Improvements for Light-Duty Vehicles—Draft Final Report”; Energy and Environmental Analysis, Inc.— NAS Report—June 4, 2001

Conclusions: A 9%-9.3% reduction can be attributed to aggressive shift logic with a 5-speed transmission

9.0–9.3 % improvement in Fuel Economy

Technology Description

Added ratio places engine in better average speed/load operating point. Improved gearbox efficiency with outstanding direct drive efficiency and reduced gear drag losses.

Improved internal oil pump losses by internally geared wheel-pump and improved volumetric efficiency and reduced leakage losses.

Optimized oil supply with reduced leakage in the hydraulic controls and gearbox.

Primary Benefits

Less pumping loss at low load conditions; less friction power loss at the same FMEP; less idle losses

Secondary Benefits

Improved transmission efficiencies

FC Improvement

Baseline: 4-speed, Reference: 5-speed

3 ~ 5%

1 ~ 2 %

Example of Application

BMW 7-Series

Reference

ATZ 9/2000, “6-Speed Automatic Transmission for the New BMW 7-Series;” Wolfgang Hall, Christian Bock

Conclusions: A 5% reduction can be attributed to the new 5-speed transmission

5% on combined M-H FTP-75

Technology Description

Aerodynamic drag reduction via vehicle shape changes or reduced frontal area

Primary Benefits

Reduced higher speed engine load required

Secondary Benefits

None

FC Improvement

Baseline: conventional vehicles; Reference: conventional vehicles

1 ~ 2%

1 ~ 2%

Example of Application

Reference

“Technology and Cost of Future Fuel Economy Improvements for Light-Duty Vehicles—Draft Final Report”; Energy and Environmental Analysis, Inc.— NAS Report—June 4, 2001

Conclusions: A 10% drag reduction is possible with a result in 1.6–2.2 % FE reduction.

1.6 to 2.2% fuel economy reduction

Technology Description

Reduced bearing, brake and driveline rotating forces. Improvements in tire rolling resistances through new tread designs and tire carcass improvements

Primary Benefits

Reduced engine load required over entire speed range

Secondary Benefits

None

FC Improvement

Baseline: conventional vehicles; Reference: conventional vehicles

1 ~ 1.5%

1 ~ 1.5%

Example of Application

Reference

“Technology and Cost of Future Fuel Economy Improvements for Light-Duty Vehicles—Draft Final Report”; Energy and Environmental Analysis, Inc.— NAS Report—June 4, 2001

Conclusions: A 10% rolling resistance reduction is possible with a result in 1.5–2.0% FE reduction

1.6 to 2.2% fuel economy reduction

Technology Description

Added weight to account for anticipated future safety structure, equipment or other features

Primary Benefits

Increased engine load required

Secondary Benefits

None

FC Improvement

Baseline: conventional vehicles, Reference: conventional vehicles

–3 ~ –4%

–3 ~ –4%

Example of Application

Reference

“Technology and Cost of Future Fuel Economy Improvements for Light-Duty Vehicles—Draft Final Report”; Energy and Environmental Analysis, Inc.— NAS Report—June 4, 2001

Conclusions: 10% weight reduction results in 6.6 to 8% reduction in FE. With a safety weight increase of 5% the committee used 3 to 4% FE reduction to account for this.

3 to 4% increase

Technology Description

Electronic or hydraulically controlled, mechanically actuated continuous variable valve timing and lift

Primary Benefits

Less pumping losses: much less, or no, intake throttling for load control. Higher thermal efficiency: better mixture formation with intake valve throttling.

Less friction: higher mechanical efficiency due to higher engine IMEP.

Secondary Benefits

Less pumping losses: engine down size with higher power density

FC Improvement

Base: 2V baseline engine; Reference: VVT engine

8 ~ 16%

3 ~ 6%

Example of Application

BMW Valvetronic

Reference

MTZ 10 2001, pp. 826–835

Conclusion: Valvetronic creates a fuel consumption reduction of 12% part load; 20% in idle; 14% reduction of fuel consumption for MVEG III compared to its predecessor.

20% idle

12% part load

14% MVEG III

Delphi: R.J Pierik, J.F.Burkhard

SAE Paper 2000–01–1221

Conclusion: demonstrated brake specific fuel consumption (BSFC) of 12% at idle, 7–10% at low middle load, and 0–3% at middle to high load.

Idle: 12%

low: 7%

mid: 10%

high: 0–3%

(BSFC)

Hyundai/Siemens: J.Lee, Ch. Lee, J.A.Nitkiewicz SAE-Paper 950816

Conclusion: For a 2.0L DOHC engine the fuel efficiency could be increased by 30% in idle; 3–4% in low speed; 5% in part load with “lost motion” technology. It uses conventional cam and create lost motion with hydraulic mechanism.

Idle: 30%

low: 3–4%

part load: 5%

high: 0%

torque: 9.8%

BMW: R.Fierl, M.Klüting

SAE-Paper 2000–01–1227

Conclusion: The electromechanical valve train offers a reduction in fuel consumption by about 10% plus 5% higher peak torque.

10%

Nissan: S.Takemura, S.Aoyama, T.Sugiyama, T.Nohara, K.Moteki, M. Nakamura, S.Hara

SAE-Paper 2001–01–0243

Conclusion: A variable actuation system showed fuel consumption of nearly 10%

10%

University of Bucharest: N.Negurescu, C.Pana, M.G.Popa, A.Racovitza SAE-Paper 2001–01–0671

Conclusion: For a one-cylinder test engine VVT increases the efficiency by 10 to 29%

10–29% efficiency

Technology Description

Completely variable valve timing controlled and actuated by electromagnetic or high-pressure hydraulic means

Primary Benefits

Less pumping losses: completely eliminate intake throttling valve for load control

Higher thermal efficiency: higher compression ratio with less knocking tendency; better mixture formation with intake valve throttling Less friction: less valve train friction; higher mechanical efficiency due to higher engine IMEP

Secondary Benefits

Less pumping losses: engine down size with higher power density

FC Improvement

Base: 2V baseline engine; Reference: VVT engine

10 ~ 20%

5 ~ 10%

Example of Application

FEV EMV; Siemens EVT

Reference

FEV: M.Pischinger, W.Salber, F.van der Staay, H.Baumgarten, H. Kemper

FISITA—Seoul 2000

Conclusion: a reduction of 16% fuel consumption can be achieved by using the EMV-technology in a 1.6L-I4–4V engine

16% with EMV

Technology Description

Using higher compression ratio at low load condition for high thermal efficiency and low compression ratio at high load conditions to avoid knocking. Normally applies to supercharged-down size engines.

Primary Benefits

Higher thermal efficiency at part load conditions

Secondary Benefits

None

FC Improvement

Base: 2V baseline engine; Reference: 4V OHC engine and supercharge down sizing

9 ~ 18%

2 ~ 6%

Example of Application

SAAB VCR engine

Reference

Saab: H.Drangel, L.Bergsten

Aachen Kolloquium 2000

Conclusion: With the combination VCR/high charging and downsizing of the engine, it was possible to get the same power out of an 1.6L-I5–4V engine as a 3.0L-V6 engine. The resulting fuel consumption reduction is 30%

30%

Daimler-Benz: F.G.Wirbeleit, K.Binder, D.Gwinner

SAE-Paper 900229

Conclusion: In a V8 a VCR between 8 to 13.9:1 depending on the engine speed, the fuel consumption improves by 4% to 8%

4%-8%

Ford/University of Dar es Salaam: T.H.Ma, H.Rajbu

SAE-Paper 884053

Conclusion: At 1,500 rpm and 2 bar BMEP condition, VVT alone achieves 8% BSFC; VVT+VCR achieves 19%

11% BSFC (1,500 rpm and 2 bar BMEP)

Technology Descriptions

Improved gearbox efficiency with improved efficiency and reduced gear drag losses.

Elimination or significant reductions of internal oil pump losses.

Primary Benefits

Improved transmission efficiency

Secondary Benefits

None

FC Improvement

Baseline: 4-speed, Reference: 6-speed

6 ~ 10%

3 ~ 5%

Example of Application

Reference

SAE Toptec—Modern Advances in Automatic Transmission Technology, “EMAT—Electro-Mechanical Automatic Transmission”; D.Carriere, J. Cherry, R.Reed, Jr.

Conclusions: An estimated 10% improvement in fuel efficiency with improved performance

Estimated 10% Improvement in fuel efficiency

Technology Description

Improved transmission efficiency using toroidal-shape and roller elements and special traction fluids.

Permits use in higher torque applications.

Primary Benefits

Improved transmission efficiency.

Brings CVT to higher torque applications.

Secondary Benefits None

FC Improvement

Baseline 4-speed; Reference: CVT

6 ~ 13%

0 ~ 2%

Example of Application

Reference

Mazda’s Future—Cars and Technology for Tomorrow

Conclusions: A 20% improvement in fuel economy in the Japanese 10–15 mode compared with a current 4-speed automatic transmission

20% Improvement in fuel economy

Technology Description

Integrated starter generator (ISG) cuts off fuel supply at idle and when the brakes are applied. Greater starter power enables the engine to be started immediately at higher speed.

Primary Benefits

Less fuel loss when engine power is not necessary

Secondary Benefits

None

FC Improvement

Base: 2V baseline engine; Reference: 4V OHC engine

6 ~ 12%

4 ~ 7%

Example of Application

Reference

“Technology and Cost of Future Fuel Economy Improvements for Light-Duty Vehicles—Draft Final Report”; Energy and Environmental Analysis, Inc.— NAS Report—June 4, 2001

Conclusions: Technology will provide for idle off, launch assist, improved power generation with a 9%—11% FE improvement.

9to11%FE improvement

Technology Descriptions

Changing the vehicle operation voltage from 12V into 42V permitting electronically controlled thermal management (water pump). Enabling technology for 42V ISG.

Primary Benefits

Less electrical power losses with less current flow through wires; higher efficiency of the electrical components

Secondary Benefits

Enables higher efficiency ISG systems

FC Improvement

Base: 2V baseline engine; Reference: 4V OHC engine

3 ~ 7%

1 ~ 2%

Example of Application

Reference

“Wards Engine and Vehicle Technology Update,” June 15, 2001, p. 7 Conclusions: Potential for electronic thermal management is 5% FE

5% FE improvement

Technology Description

Using electric motor to drive power steering

Primary Benefits

Reduced parasitic losses due to optimized operation (only when needed)

Secondary Benefits

None

FC Improvement

Base: 2V baseline engine; Reference: 4V OHC engine

3.5–7.5%

1.5 ~ 2.5%

Example of Application

Reference

ZF Lenksysteme: D.Peter, R.Gerhard SAE-Paper 199–01–0401

Conclusion: Reduction of fuel consumption by 2–3% by using electrical power steering instead of hydraulic power steering for a medium-sized vehicle.

2–3%