Scientists Claim Major Leap in Engine Design

An anonymous reader writes "Purdue researchers say they have made a major advance in the design of the internal combustion engine, one that could seriously boost fuel efficiency and cut emissions. A key portion involves building intake and exhaust valves that are no longer driven by mechanisms connected to the pistons, a departure from the way car engines have worked since they were commercialized more than a century ago. 'The concept, known as variable valve actuation, would enable significant improvements in conventional gasoline and diesel engines used in cars and trucks and for applications such as generators, he said. The technique also enables the introduction of an advanced method called homogeneous charge compression ignition, or HCCI, which would allow the United States to drastically reduce its dependence on foreign oil and the production of harmful exhaust emissions. The homogeneous charge compression ignition technique would make it possible to improve the efficiency of gasoline engines by 15 percent to 20 percent, making them as efficient as diesel engines while nearly eliminating smog-generating nitrogen oxides, Shaver said.'"

Comments

Doesn't Sound That New

[Nom du Keyboard]

This doesn't sound that new, at least not in concept. Actuating engine valves with something other than camshafts, lifters, pushrods, and rocker arms as been around as an idea for a long time. I recall a Tucker prototype engine in the San Diego Automotive Museum (Balboa Park) that explored that concept. And Honda VTEC, IIRC, varies valve timing based on RPM.

Yeah, mechanical valve actuation has its problems. It makes for either non-optimal valve placement (standard wedge heads) or overly complicated mechanical actuation trains (see Chrysler original Hemi engine design). So a better method to actuate valves than driving it from a fixed, or fixed-variable, design could make for better engine performance overall. That's hardly new. As best I've seen, this has been merely an engineering problem to determine a better way to actuate valves that meets the requirements of cost, durability, cost, performance, and cost -- when it comes to consumer engines. While such an actuator method is certainly significant news in and of itself, it's not like someone has redone the whole engine.