Diesel engine
Diesel engine can be also called self-ignition engine or compression ignition engine. The maximum factor pressure in this engine is higher than in the low-pressure engines with spark ignition.
For this type of engine, fuel coming from the distillation of crude oil is used. This fuel is known as diesel fuel (diesel). It has a high cetane number, which is required in the case of diesel. Diesel fuel used for diesel engines has also a function of lubricants in the fuel injection system. Biofuels do not have these functions (e.g. rapeseed oil) and therefore it cannot be used in such engines. Biodiesel also has a low cetane number, which increases the delay of ignition and the engine falls in the area of smoke. In addition, biofuels have a lower calorific value than diesel fuel, so they wear out quickly.
The calorific value of diesel fuel is slightly higher than gasoline, and its obtainment is much easier, hence its lower price. The cost of diesel is increasing in autumn and winter. This is because in those seasons the demand for obtaining oil is increasing.
Unfortunately, diesel contains large amounts of sulfur compounds, which means that its combustion is harmful to the environment.
Diesel oil derived from crude oil (not vegetable oil - biodiesel or other raw materials such as natural gas) in the English terminology is called petro diesel. In this way, it is possible to distinguish it from the oil produced in other ways.
We must be especially careful when using diesel engine in winter. During this period the risk that the car will not start is growing. This results from the construction of a diesel engine. The air is injected into the cylinders of diesel drive unit, and then diesel oil is injected directly above the piston. During the initial combustion the components in the combustion chamber inject fuel. At this point, the air placed there must be additionally heated. Glow plugs are responsible for that (heat up the air in the cylinder and combustion chamber). Next, self-initiate combustion process begins due to the interaction of high pressure and temperature above the piston. In the case of gasoline, this process is initiated by electric spark that causes an explosion of the mixture and start the engine. During the great winter freeze the whole block diesel engine is more cooled, which makes it difficult to warm up the combustion chamber. Unfortunately, in individuals with self-ignition fuel freezing may occur ( -10 degrees Celsius). This is because at low temperatures paraffin is settled from diesel oil, which in the form of tiny crystals clog the fuel filter. Then there is a need to leave the car in a heated garage. To prevent this it is recommended to add some substances to improve diesel oil.
Owners of the cars with diesel engines can boast of lower fuel burning than gasoline cars owners. Unfortunately, since January 2012 excise tax on diesel is expected to increase, so the prices at the petrol stations will rise again. Then the difference between gasoline and crude oil may not be significant so the self-ignition engines will become unprofitable.