20 automotive deSign
Fuel efficiency drives next phase of automotive engines
Fig. 1.
For 100 years the four-stroke internal combustion engine has been the dominant automotive powerplant, but there is a pressing need to improve fuel efficiency, emissions and power density beyond what can be achieved through fine- tuning this concept. Paul Stevens reports on some innovative alternatives.
Scuderi’s split-cycle engine divides the four strokes of the combustion cycle over two paired cylinders: one intake/ compression cylinder and one power/ exhaust cylinder.
O
n a day-to-day basis it can be difficult to see how the marketing messages associated with a product are shifting. But look
across a number of decades and it can be seen how much aspirations have changed and how the products have developed to reflect that. The marketing of cars in the 1980s, for example, was all about levels of equipment. A car that offered electric windows, a radio-cassette player and a sunroof was considered quite special, yet those features soon become standard equipment in most manufacturers’ brochures. Through the 1990s, a key area of product differentiation was coefficient of drag (Cd). If a manufacturer could claim that its latest vehicle had the lowest Cd in its class, then that was a major selling point. By the end of the decade, though, it was difficult to
www.engineerlive.com
find any mention of Cd even in the small print. Automotive marketing through the early
years of the twenty-first century was strongly focused on safety, with the introduction of the European NCAP ratings, and manufacturers competing vigorously to offer ever more effective crumple zones and increasing numbers of air bags. Just a few short years later, though, high levels of safety are largely taken for granted. A focus for differentiation within the automotive industry today is fuel efficiency and pollution. Sources of fossil fuels look to be running dry, and petrol (gasoline) costs have risen steeply, so engine manufacturers are under pressure to come up with designs that do more with less. And with global warming now broadly accepted as a scientific fact, the need to
➠
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36