There are several possible ways to classify internal combustion engines.
By number of strokes
Clerk Cycle 1879 6
Four-stroke engine (Otto cycle)
By type of ignition
Spark-ignition engine (commonly found as gasoline engines)
By mechanical/thermodynamical cycle (these 2 cycles do not encompass all reciprocating engines, and are infrequently used):
The following jet engine types are also gas turbines types:
Surfaces in contact and relative motion
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
Big end bearings
Valve gear (The following elements may not be present):
Timing chain or gears. Toothed belts do not require lubrication.
Win in the competition
We can easily notice that the cars or motorcycles are very often one of the main prizes in various competitions or sweepstakes. Why is it like that ? Well, these machines are often very valuable and can significantly make life easier for the winner. So valuable prize is designed to encourage more participants to take part in the common play or boot from the competition. It is a very proven grip, which for years makes competitions with prizes automotive enjoyed considerable popularity. Admittedly, win a car or a motorcycle or any other vehicle is also associated with considerable charges, which obliges us right relating to competitions; not discouraged, however, many taking part in all kinds of lotteries.