A typical gasoline powered automobile has about 25% thermal efficiency – meaning only 25% of gasoline used in the engine is used to actually power the car – the rest is wasted in heat transfer, escape of unburnt fuel via exhaust and emissions.

Diesels are lot more effective. But even the best diesel engine in the entire world only has 50% thermal efficiency. (here)

Bottomline :- Most of the gas we burn in engines is wasted.

Both Gasoline and diesel have different advantages and disadvantages when it comes to powering internal combustion engines.

Diesel burns much more easily compared to gasoline.But on the flip side, diesel engines pollute a lot more than gasoline engines. Also, fuel injection system for diesel engines is a whole lot more expensive than those needed in gasoline engines.

University of Wisconsin-Madison engine research group lead by Rolf Reitz has stuck on idea of harvesting the advantages of both diesel and gasoline in the same engine,  using a fuel injection system to spray a mixture of diesel and gasoline into a (diesel) engine in a (gasoline vs diesel) ratio that would change in real time depending on the power need.

Under heavy-load operating conditions for a diesel truck, the fuel mix in Reitz’s fueling strategy might be as high as 85 percent gasoline to 15 percent diesel; under lighter loads, the percentage of diesel would increase to a roughly 50-50 mix. Normally this type of blend wouldn’t ignite in a diesel engine, because gasoline is less reactive than diesel and burns less easily. But in Reitz’s strategy, just the right amount of diesel fuel injections provide the kick-start for ignition.

“You can think of the diesel spray as a collection of liquid spark plugs, essentially, that ignite the gasoline,” says Reitz, the Wisconsin Distinguished Professor of Mechanical Engineering. “The new strategy changes the fuel properties by blending the two fuels within the combustion chamber to precisely control the combustion process, based on when and how much diesel fuel is injected.”

The idea was first modeled in Reitz’s lab using technique developed called genetic algorithms, which borrows some of the same techniques of natural selection in the biological world to determine the “fittest” variables for engine performance) and then actually tried out using a Caterpiller engine.

The results are dramatic -

• 53% thermal efficiency,
• 40% less heat and
• breezed through the 2010 EPA pollution standards mandate
• uses inexpensive gasoline fuel injection instead of high pressure diesel injection system.

What it means :-

If its implemented in all gasoline and diesel engines in US. It will save as much as 4 million barrels of oil per day. For record, its about the amount of oil we import from middle east every day.

Also EPA mandate on diesel pollution standards is a hard issue for existing diesel manufacturers who have been experimenting with injecting urea (needs a tank for urea fuel) into catalytic converter and using ultra high pressure fuel injection to reuse exhaust; A few of the manufacturers are even quitting the market place.

Will mean vehicles will have to carry two tanks – one for gasoline and another for diesel.

Acknowledgment : University of Wisconsin-Madison, gizmag, Image in thumbnails is used under creative commons courtesy of Luc Viatour, Image in article is used under creative commons  via US govt and flickr.