http://sync.sympatico.msn.ca/news/conte ... bled=false
I was told recently that hybrid outboards had been built for the US military that will burn several types of fuel. Now this.
Engineer builds diesel-gas hybrid engine
03/08/2009 1:55:46 PM
Researchers at the University of Wisconsin have developed an engine that runs on a mix of diesel and gasoline that produces fewer emissions and is as much as 20 per cent more fuel-efficient than conventional engines.
CBC News
(Mike Wintroath/Associated Press)
Led by mechanical engineering professor Rolf Reitz, a research team at the school presented their findings at a diesel engine conference in Detroit sponsored by the U.S. Department of Energy.
Diesel engines are typically more energy-efficient than gasoline, but the emissions they produce can often be more toxic than those that are spewed out of typical unleaded gasoline engines.
But by blending the two together, Reitz and his team were able to change the fuel's properties to control the combustion process.
The key appears to be what Reitz describes as "fast-response fuel blending" where the engine alters the ratio of diesel-to-gas based on real-time conditions.
In a truck carrying a heavy load, for example, the ratio might be as high as 85 per cent gasoline to 15 per cent diesel; under lighter loads, the percentage of diesel would increase to a roughly 50-50 mix.
That half-and-half mix wouldn't normally ignite in a diesel engine because gasoline is less reactive. But the team got around that by injecting diesel at the right time to kickstart ignition.
"You can think of the diesel spray as a collection of liquid spark plugs, essentially, that ignite the gasoline," Reitz said.
Reitz estimates that if all cars on the road could match the fuel efficiency gains simulated in the project, it would lead to a one-third reduction of the amount of oil the United States uses for transportation - or roughly the entire amount it imports from the Persian Gulf every day.
Roughly two-thirds of the 21 million barrels per day that the United States consumes are used in the transportation industry.
Less heat emitted
The hybrid engine also operates at roughly 40 per cent lower temperatures than conventional engines, which translates into far less energy lost from the engine in the form of thermal heat.
The efficiency gains exceed even the most efficient diesel engines in the world, the massive engines used in the maritime shipping industry.
"For a small engine to even approach these massive engine efficiencies is remarkable," Reitz said.
Beginning in 2010, the Environmental Protection Agency has imposed stringent new requirements that diesel engines must cut 90 per cent of their particulate output and 80 per cent of all nitrogen oxide emissions.
Many companies have pulled out of the diesel engine market altogether because of the difficulties anticipated in meeting those requirements. But the prototype had no problem meeting the requirements, Reitz said.
Although the findings have obvious potential for the commercial trucking industry, there is ample reason to believe the fuel-blending technology would work just as well in cars, Reitz said, because it works just as well in the low-pressure fuel injection systems commonly used in mainstream passenger vehicles.