What is Effciency?

Answer 1

Efficiency in cars is all to do with how far you can go with a limited amount of fuel (say, a full tank of gas). The efficiency of a car, and the reasons why different cars are more or less efficient than others can be broken into a number of categories: 1. Efficiency of the engine - how 'cleanly' the fuel in the engine burns. The engine must achieve the correct air-fuel mixture to burn the fuel as completely as possible, otherwise fuel is left un-burnt and goes to waste out your tailpipe. - how much the fuel-air mix is compressed in the engine. Basically, the higher the compression of the fuel-air mixture in the engine, the higher the amount of power the engine can put out. Compressing the fuel-air mixture (more than a 'normal' level, by use of a turbocharger) also alows the fuel to burn more completely. - The size of the engine. This is generally the determining factor in car efficiency, as a larger size engine will ALWAYS use more fuel, no matter what car it is put into, as the engine requires more fuel to just 'turn over' at cruising highway speeds and when idling. Only when overtaking with you're foot down does a larger engine actually become 'efficient'. It is a known fact that most drivers only use the maximum power output of their engine in general driving less than 1% of the time. - Friction in the engine. Including how well maintained and lubricated the engine is. Also, the general design of the engine. (For example, "V" shape engines are generally more efficient at power delivery to the flywheel than "straight/inline" engines. 2. Aerodynamics of the car body. Design of the car effects the efficiency of a car. For example, large 4-wheel-drives (Such as a Landcruiser, Patrol, etc) or mini-vans have much greater wind drag than smaller cars, as the surface area is larger and the approach angle of the windscreen is generally steeper, etc. 3. Friction in vehicle parts. For example, under pressure (below correct pressure) tires will decrease the efficiency of the vehicle by causing more friction and consequently more force required to turn them. 4. Weight. This is the final determining factor in the efficiency of a vehicle. Newtons laws tell us that a body with more mass requires a greater force (more energy) to move a distance. Therefore, a heavier vehicle will require more fuel to move through the air and along the road than a lighter one. Removing excess weight from your car (for example camping equipment, chairs, luggage, etc) may improve your car's efficiency.