With all the talk on alternative fuels and fuel economy regulations, it’s easy to overlook the fact that a lot of very interesting engine research is going on today. And while the primary focus at the moment is on automotive applications, there is no reason to think that some of these designs – if they prove to be valid – won’t find their way into truck engine bays at some point in the future.
Surprisingly, a lot of this research is calling decades – or even century – old concepts about combustion and fuel types in question.
First up is a diesel engine that has been modified to run on gasoline. Researchers who developed this at Lund University in Sweden say the new design could halve fuel consumption for gasoline engines.
The engine has been developed to achieve the right amount of ignition delay; meaning a delay between fuel injection and combustion. During the ignition delay, the mixing that happens produces minimal amounts of soot and nitric oxide. In fact, it could mean a new generation of engines so clean they wouldn’t require catalytic converters.
It also means greater efficiency – the Lund University engine currently has 57 percent indicated efficiency, almost a world record. This translates into roughly 50 percent efficiency on the output shaft of the engine.
“A reasonably efficient engine today would be in the range of 40-42%. We’re hoping to achieve 60% with this type of PPC combustion process”, says Bengt Johansson, Professor of Combustion Engines at Lund University.
A higher efficiency could have a large impact on fuel consumption, and therefore also CO2 emissions. Big trucks consumed 28 billion gallons of gasoline in 2011 in the US alone, according to US Department of Transportation statistics.
A second design with interesting potential was reported by Car & Driver just this week. Developed by Hyundai and Delphi, the Gasoline Direct-Injection Compression Ignition (GDCI) engine is a gasoline engine that doesn’t use spark plugs to initiate combustion. The engine is still in experimental stages, but already yielding efficiency results on par with diesel engines while being much cleaner burning.
More results from the GDCI engine will be obtained later this year when Hyundai begins track testing the design.
But, as these two concept engines make clear, the last word has yet to written on internal combustion engine design.