Motor manufacturer and tuner, Ilmor Engineering, has branched out from its Indy Car, Formula One, NASCAR, and MotoGP duties, and produced what they call a five-stroke motor. With dual camshafts and an asymetrical three-cylinder configuration, the Ilmor is more than intriguing with its design, and promises to bring real benefits both to the race track, and to road-use. Most notably is a 10% increased fuel efficiency, and 20% weight reduction in power-plant weight.
With its 700cc, turbocharged, prototype motor, Ilmor is able to extract 130hp and 122 lbs•ft of torque. To achieve this, the motor employs two overhead camshafts. One is a “high pressure” camshaft, which turns at half the crank speed, while the other shaft is a “low pressure” camshaft, which turns at the same speed as the crankshaft.
The high pressure shaft powers the two outside cylinders, which operate like a normal four-stroke motor, while the low pressure shaft powers the larger center cylinder, which gathers exhaust flow from the other two cylinders. This larger cylinder can also adjust its expansion and compression strokes, allowing it to be tuned for specific applications.
Ilmor hopes that this new design will allow its motor to be more fuel efficient over normal four-stroke gas motors. With no exotic materials or elaborate construction processes, the design should be fairly simple to implement in a variety of applications. Of course the most relevant to our concerns is for motorcycle racing and production. Ilmor has tried on several occasions to join the MotoGP ranks, and with fuel consumption a fairly large concern with the current fuel tank restrictions, Ilmor may have a nice competitive advantage brewing here. They will of course have to overcome the fact their design uses forced induction, but anything could happen with future regulations.