Lubrication Diagram of an engine using pressurized lubrication Wikimedia Commons has media related to Internal combustion piston engine lubrication systems. Surfaces in contact and relative motion to other surfaces require lubrication to reduce wear, noise and increase efficiency by reducing the power wasting in overcoming friction, or to make the mechanism work at all.
At the very least, an engine requires lubrication in the following parts: Between pistons and cylinders Small bearings Big end bearings Main bearings Valve gear (The following elements may not be present): Tappets Rocker arms Pushrods Timing chain or gears.Toothed belts do not require lubrication. Źródło: https://en.wikipedia.org/wiki/Internal_combustion_engine
Jet engine Main article: Jet engine Turbofan Jet Engine Jet engines use a number of rows of fan blades to compress air which then enters a combustor where it is mixed with fuel (typically JP fuel) and then ignited.The burning of the fuel raises the temperature of the air which is then exhausted out of the engine creating thrust.
A modern turbofan engine can operate at as high as 48% efficiency.
Most cars are designed to carry multiple occupants, often with four or five seats.
Cars with five seats typically seat two passengers in the front and three in the rear.Full-size cars and large sport utility vehicles can often carry six, seven, or more occupants depending on the arrangement of the seats. In the other hand, sports cars are most often designed with only two seats.