Gasoline and diesel engines are still on the mainstream of car technology, as you can see if you look on the streets. Having to withstand the difficulties that electric cars pose to their market share, the automobile industry is now trying to compensate and anticipate the inevitable boom that the hybrids and EVs will cause in the following years.
Researchers from the University of Wisconsin-Madison have recently unveiled a concept engine that can be from 20 to 30 percent more fuel-efficient than classic models. It would also be substantially cheaper to produce, since the emissions are lower than those of conventional engines and expensive catalyst units are not needed any longer (in some cases, their price can reach that of the engine’s).
The concept of mixing gasoline and diesel in an engine is not new. Empirical rumors and experienced drivers’ tales say that, in some degree, this mixing does good to the engine by improving combustion. Others, far more rejected by the science community, say that by mixing hydrogen and diesel or gasoline does even better (and I tend to believe them). You’ll see why when you’ll read below.
It’s a known fact that diesel engines are more efficient (40 – 45 percent) than their gasoline counterparts (30 percent). The researchers designed modifications for both diesel and gasoline engines.
In the diesel engine, gasoline from one fuel tank is injected into the intake port near the combustion chamber, where it mixes with air before moving into the chamber (this is the conventional form of fuel injection in gasoline vehicles). Then diesel fuel from another tank is injected directly into the chamber using a low-pressure fuel injector. As this mixture is compressed, the diesel ignites first, followed shortly by the gasoline, which is more resistant to combustion. Controlling the ratio of the two fuels determines both the timing of the combustion and how long it lasts. The design requires precise control over the fuel injection, as the ratio and distribution of the two fuels in the chamber needs to change depending on the load placed on the engine. With light loads, the mix is about 50-50, while heavier loads might need as little as 5 percent diesel. The resulting engine is about 55 percent efficient (a 10 percent gain).
In the version designed to replace conventional gasoline engines, the diesel fuel is replaced with gasoline that’s mixed with an additive to make it more reactive, improving ignition of the fuel. Instead of having two fuel tanks, the car needs only one gasoline tank and a small reservoir the size of a window-washing-fluid bottle to hold the additive. Ordinary gas is injected by the port injector, and gas mixed with the additive is injected directly into the chamber. The result is an engine that’s 45 percent efficient, compared to about 30 percent efficient for conventional gasoline engines.
Try as they might, these figures are still way behind the efficiencies of the electric motor. Petrol is still going to need to be extracted and refined, and CO2 and other harmful gases will still pollute the atmosphere while we use fossil fuels. These improvements represent an advance that could have had well been released on the market decades ago, in my opinion. And, based on the principle of gasoline burning after the diesel, why couldn’t we use hydrogen instead, and give the hydrogen infrastructure a big boost, as well as to fuel consumption worldwide?
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[via Technology Review]