• Aug 11th 2009 at 9:28AM
  • Add
English engineering firm Ilmor knows all about engine design, having produced powerplants for Formula One, IndyCar, and NASCAR. But its latest internal combustion creation, in contrast to those racing engines, is designed to burn fuel more frugally: a gas-powered five-stroke with diesel consumption.

It starts with a three-cylinder, 700cc, turbocharged engine with 130 hp and 122 lb-ft. There are two overhead camshafts: a high pressure shaft turning at half the crank speed working on the two high pressure cylinders, and a low pressure shaft running at crank speed for the third cylinder. The two outside, high-pressure cylinders work like a normal four-stroke, but alternate their exhaust flow into the third, central low-pressure chamber. That cylinder's expansion and compression strokes aren't fixed, so it can be selectively tuned for the best expansion ratio.

The principle is that extra work gets done for the same amount of gas, and Ilmor claims increased fuel efficiency over conventional gas engines. The five-stroke is made with current, in-use technology so there'd be no extra costs for exotic materials or processes, and it's said to be "relatively compact." Ilmor says the next step is to build another working prototype with targets of 10% better fuel efficiency and 20% less engine weight compared to an equivalent four-stroke engine.

[Source: Ilmor via Motor Authority]

I'm reporting this comment as:

Reported comments and users are reviewed by Autoblog staff 24 hours a day, seven days a week to determine whether they violate Community Guideline. Accounts are penalized for Community Guidelines violations and serious or repeated violations can lead to account termination.

    • 1 Second Ago
  • 2015 Toyota Highlander
    MSRP: $29,765 - $44,140
    2015 Honda Accord
    MSRP: $22,105 - $33,630
    2015 Toyota Corolla
    MSRP: $16,950 - $22,955
    2015 Mazda Mazda3
    MSRP: $16,945 - $25,545
    2015 Jeep Grand Cherokee
    MSRP: $29,995 - $64,895
    Share This Photo X