Advanced Automotive Technology: Visions of a Super-Efficient Family Car

TABLE 3-5:

Summary of Long-Term Fuel

Efficiency Benefits from Advanced Technology

Fuel consumption impact (%)

Manufacturers mean Optimistic

4-valve engine with simple variable

resonance intake Base Base

2-valve engine +4 +5

4V with camphasing

+VRI -2 -3

4V with 2-position VVLT

+VRI -6 -9

4V with full VVLT

+ VRI -8 -11

4V with full VVLT + cyl. shutoff

+ VRI -lo -13

4V + VVLT + lean bum

+ VRI -12 -15

DISC (+ VVLT ?) -15 -19

Friction: roller cams -1 -2

Piston/rings/crankshaft -1.5 -4

KEY: VRI = variable resonance intake manifold; VVLT = variable valve lift and
timing; DISC =direct injection stratified charge; + indicates increased fuel consumption,

• a decrease.

SOURCE: Energy and Environmental Analysis, Inc., “Automotive Technologies To
Improve Fuel Economy to 2015,” prepared for the Office of Technology Assessment,
June 1995.