Quote:
Originally Posted by bwilson4web
Weight as a turbo-charger lets a physically smaller engine perform at power levels a substantially heavier engine would require. It breathes like a big bore and makes power like a big bore but it is much lighter so there is less rolling drag and inertial losses (aka., when the brakes have to slow or stop the car.)
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Why don't manufacturers turbo-charge all cars? It seems a sure bet it would more than pay for itself by avoiding the need to build a bigger engine, and in fuel savings.
Quote:
Originally Posted by cleanspeed1
Gasoline direct injection allows higher compression ratios, but once again, if the fuel quality is such that it does not react completely, you will have pre-ignition/detonation problems. This has been dealt with through higher injection pressures, better atomization and knock sensing ignition systems by and large.
Every fuel has an ideal fuel to air ratio chemically and diesel fuel is no exception.
It's all about control. Diesel engines are designed to withstand high cylinder pressures and abnormal combustion events, along with very lean mixtures. The fuel allows this.
That rattle that comes from a diesel? Detonation / pre ignition.
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My point is, it would actually be desirable for fuel to instantly combust if it is directly injected into the cylinder just at the right moment in the engine cycle. It shouldn't then matter what octane the fuel is since we want it to burn right as it gets squirted in. Diesels do this.
Surely gasoline engines can be designed to withstand the increased pressures, heat and such. Diesel engines do this while burning a fuel that has 30% more energy density.