The Greatest Waste Of Fuel And Energy

It is well-known how inefficient car engines really are. What this means is that, no matter how well an engine is designed, most of the energy in the fuel that is released by combustion in the cylinders goes to produce heat, instead of useful mechanical energy. This is why an engine requires a cooling system. The engine would not take long to self-destruct if the excess heat could not be absorbed by liquid coolant and dissipated through the radiator.

What this means is that whenever you stop to put that expensive fuel into your tank, the majority of the energy in that fuel, which will be released in the engine, will not go into getting you to your destination. Rather, it will go toward heating up the coolant in your engine so that the heat can be dissipated by the radiator.

To be sure, this engine heat is not all wasted. Engine heat is useful in that it reduces the viscosity of the oil, enabling it to flow more readily to lubricate the engine parts. This is why the worst wear and tear on the engine occurs when it is started, before the oil has begun to flow. This also explains why an engine will wear faster in a cold climate.

Engine heat also warms the incoming air from the air filter, so that it can hold more vaporized (vapourised) fuel on it's way into the cylinders for combustion. Does anyone remember older cars, in which a choke would be closed upon starting to block incoming air so that the fuel-air mixture would not be too lean? The choke would then be opened after the engine had gained some warmth.

Finally, of course, the engine heat warms the passengers in cold weather when the antifreeze/coolant is circulated through small radiators in the passenger compartment. Readers in colder climates may have noticed that there are trucks in the winter with cardboard placed over the radiator grill to conserve heat in the engine.

Nevertheless, the fact is that most of the energy in the fuel that is released by combustion in your engine goes to produce heat, and most of that heat is wasted by dissipation through the radiator. What would it be like if we could only save or make use of this tremendous amount of wasted energy?

When combustion takes place in a cylinder of the engine, we want the combustion to be as rapid as possible. The quicker the combustion, the more mechanical energy is produce by the force of the rapidly expanding exhaust gases against the piston, as opposed to heat. The slower the combustion, the more energy is ends up as heat instead of useful mechanical energy.

Efforts have been made to speed combustion by using dual spark plugs in the cylinder, or by using small lasers to initiate combustion instead of spark plugs. But no matter how quickly combustion can be made to take place, or how efficient the engine can otherwise be made, most of the energy in fuel ends up as heat, and not as useful mechanical energy. The noise that is produced by an engine also requires energy, and is another route of waste.

This waste heat cannot be converted into mechanical energy, as it stands now. Saving heat wouldn't do any good either, if we insulated the engine to hold in heat it would only run hotter and not more efficiently.

But what if we could develop a small and efficient boiler, and replace the radiator with it? A boiler can generate electricity by using steam to move a piston. When boiling water under pressure is suddenly given the chance to expand, it will vaporize (vapourise) into steam which will exert great pressure on the piston, which would then move to create relative motion between a magnet and a coil of wire. We would logically use water, instead of the usual engine coolant, because the coolant raises the boiling point of water so that more energy would be required to make the steam. The energy which would otherwise be lost as heat from the engine could then be recouped as electricity.

The trouble is that small boilers are inefficient. The reason for this is that surface area is two-dimensional, while volume is three-dimensional. So as the size of something is reduced, the volume decreases faster than the surface area. It is from the surface area of a boiler that heat leaks away as waste. So, a smaller boiler will lose a greater proportion of heat, because it has a greater surface area relative to volume, and will thus be less efficient than a larger boiler. If you have ever seen a demonstration of a steam locomotive, it is easy to feel how much heat it throws off. This heat is, of course, waste.

However one crucial difference between a boiler and an internal combustion engine, with regard to efficiency, is that holding in heat by insulation will improve the efficiency of a boiler, while it would only make the engine run hotter.

Suppose that a car had a small, but efficient, insulated boiler which would use the waste heat from the engine to produce electricity. This boiler would not need to be any larger than the radiator is, which the boiler would replace. The electricity produced by this boiler would charge batteries, until there was enough electricity stored in these batteries to run the car on an electric motor, or four small electric motors, one at each wheel.

Think of pre-nuclear submarines. There used to be both a diesel and an electric motor on these boats. The sub would run on the diesel motor while on the surface. All the while, this motor would be re-charging the ship's batteries. Then, while the sub was submerged, it would run on the electric motor, drawing it's energy from the charged batteries. The electric motor, unlike the diesel motor, can operate underwater because it has no need of air.

Just think of the fantastic amount of energy that this would save. I think that this is a whole new avenue in the search for energy, and the effort to lessen global warming. In fact, I am sure that is is possible to design a dual engine which could operate either as an internal combustion engine or as an electric motor, so that the car would not require a separate electric motor. The car could automatically switch between electric and combustion modes according to the amount of electricity stored in the batteries.

Cars originated when fuel was cheap. Those days are long gone, but we are still using the same basic design of car. It's time for some new thinking.