Read the text and do the tasksDiesel engineA diesel engine (also known as a compression - ignition engine) is an internal
combustion engine that uses the heat of
compression to initiate ignition to burn the
fuel, which is injected into the combustion
chamber. This is in contrast to spark ignition engines such as a petrol engine
(gasoline engine) or gas engine (using a
gaseous fuel as opposed to gasoline),
which uses a spark plug to ignite an air fuel mixture. The engine was developed by
Rudolf Diesel in 1893. The diesel engine
has the highest thermal efficiency of any
regular internal or external combustion
engine due to its very high compression
ratio.Diesel engines are manufactured in two-stroke and four-stroke versions.
In the true diesel engine, only air is initially introduced into the combustion chamber. The air is then compressed with a compression ratio typically
between 15:1 and 22:1. This high compression heats the air to 550 °C
(1,022 °F). At about the top of the compression stroke, fuel is injected directly into the compressed air in the combustion chamber. The fuel injector ensures that the fuel is broken down into small droplets, and that the fuel is distributed evenly. The heat of the compressed air
vaporizes fuel from the surface of the droplets. The vapor is then ignited by the heat from the compressed air in the
combustion chamber, the droplets continue to vaporize from their surfaces
and burn, getting smaller, until all the fuel in the droplets has been burnt.
The rapid expansion of combustion gases then drives the piston downward,
supplying power to the crankshaft.Major advantages. Diesel engines have several advantages over other
internal combustion engines:They burn less fuel than a petrol engine performing the same work, due to the engine's higher temperature of combustion and greater expansion
ratio. Gasoline engines are typically 30 % efficient while diesel engines can
convert over 45 % of the fuel energy into mechanical energy.They have no high voltage electrical ignition system, resulting in
high reliability and easy adaptation to damp environments. The life of a diesel engine is generally about twice as long as that
of a petrol engine due to the increased strength of parts used. Diesel fuel has better lubrication properties than petrol as well.
• Diesel fuel is considered safer than petrol in many applications.The fuel efficiency of a diesel engine remains nearly constant, as
opposed to petrol and turbine engines which use proportionally more fuel. They generate less waste heat in cooling and exhaust. The carbon
monoxide content of the exhaust is minimal, therefore diesel engines are
used in underground mines.Are the statements true or false?1. Diesel engines use a spark plug to ignite the fuel.