Researchers use model to redesign internal-combustion engine

July 12, 2007
Researchers at Purdue University have built the first model that tracks engine performance from one combustion cycle to the next.

One of its first tasks will be analyzing an engine design that eliminates the mechanism linking the crankshaft and camshaft, and controls the valves independently. The valves would, therefore, be more finely tuned for efficiently burning diesel, gasoline, and alternative fuels, since piston movement would not restrict timing.

The concept, known as variable-valve actuation, could also handle homogeneous chargecompression ignition (HCCI). This improves efficiency of gas engines by 15 to 20%, while nearly eliminating smog-generating nitrogen oxides, according to Gregory M. Shaver, assistant professor of mechanical engineering.

In HCCI, the charge, or fuelair mixture, is homogeneous, meaning it is uniform. Adding reinducted exhaust to the charge dilutes it and increases its temperature before compression. The process also permits uniform combustion without a spark, and at lower compressions than those in diesel engines.

Inside cylinders of ordinary engines, there is a large temperature difference between portions of the air-fuel mixture after ignition. A homogeneous air-fuel mixture and reinducted exhaust would eliminate this difference during auto-ignition, decreasing combustion temperature. Lowering temperature reduces nitrogen oxides.

Learning how to automatically adjust valve motions and fuel injection to match changes in operating conditions (speed, weight, and fuel type) will be a major challenge. Engines with HCCI will use sensors that monitor performance and provide data for altering valve timing. Purdue researchers are also working on software algorithms to control combustion via variable-valve actuation.

Gregory M. Shaver, left, assistant professor of mechanical engineering at Purdue, and graduate student David Snyder discuss modifying commercial diesel engines to reduce fuel consumption and emissions. Purdue News Service photo/David Umberger

Sponsored Recommendations

NEW Low Profile, Ultra Compact Power Supplies

March 13, 2024
Learn more HERE about Altech's Power supplies!

Altech's Liquid Tight Strain Relifs Catalog

March 13, 2024
With experienced Product Engineers and Customer Service personnel, Altech provides solutions to your most pressing application challenges. All with one thought in mind - to ensure...

Industrial Straight-Through Cable Gland

March 13, 2024
Learn more about Altech's cable glands and all they have to offer for your needs!

All-In-One DC-UPS Power Solutions

March 13, 2024
Introducing the All-In-One DC-UPS, a versatile solution combining multiple functionalities in a single device. Serving as a power supply, battery charger, battery care module,...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!