Diesel engines have the reputation of being noisier than
their petrol counterparts but today's modern diesel engines
are quieter and smoother than ever. When this is combined
with their higher torque, longevity and economical running
it is easy to see why they are increasingly popular.
The characteristic coughing and rattling of diesel engines,
particularly at slow speeds, is caused by sudden fuel ignition
in the combustion chamber and these sudden temperature changes,
hence why this is more of an issue when the engine is cold
or crawling in traffic. Two stage injectors, which means
a small amount of fuel is used to warm the combustion chamber
before the full amount of fuel is injected, and electronic
control which means that fuel is injected at the most suitable
time for all speeds and engine temperatures has virtually
eliminated this issue. This has resulted in diesel entering
the mainstream car market and helped overcome their image
as a workhorse, rather than performance car.
Higher Torque - More Pulling Power
Diesel engines have a lower torque peak than petrol engines,
typically between 1600 and 2000 rpm. In the past this has
meant that whilst diesels have greater torque at slower
speeds, ideal for commercial vehicles carrying or pulling
heavy loads. However, this is not a desirable trait in consumer
vehicles. Although great when climbing hills or towing a
caravan, many drivers find the slow acceleration from a
full stop too much of a drawback.
Technological advances has meant that whilst diesel cars
still have lower torque peaks than their petrol counterparts
these are now sustained over a wider range. As the torque
does not decrease at higher speed in modern diesel cars
the result is greater acceleration and more pulling power.
Fuel Economy & Biodiesel
Diesel engines are more efficient than petrol engines and
this results in greater fuel economy. If your diesel engine
is efficient this can amount to as much as 40% more miles
per gallon than the equivalent petrol driven car and this
is in spite of the fact that diesel engines are generally
heavier.
The state of the planet is firmly in the public eye at
the moment and in this current political climate we are
all being urged to do what we can to reduce pollution. As
a result, innovations in technology and production have
led to a reduction in the damage that is caused by diesel
exhaust. For example low sulphur diesel burns much cleaner
and the emissions are lower. As well as emitting lower levels
of CO2, a diesel engine also produces less carbon monoxide.
Turbo Diesel Engines
The addition of a turbocharger (supercharger) is a typical
method of increasing the power output of a diesel engine.
Vehicles with 'turbo diesel' are ideal if you want to increase
the amount of power that is available to you, but don't
want to turn to a more environmentally damaging petrol engine.
Although denser than petrol, diesel contains more energy
(joules). Couple this with the fact that these engines are
becoming increasingly efficient and you can see why the
mileage outperforms that of a petrol engine.
Diesel engines don't have to rely on spark plugs in order
to produce their power, which in turn means that is one
less electrical failure for you to worry about. These engines
intake air and compresses it before release into the compression
chamber.
The lifetime of this type of engine is considerably longer
than that of a typical petrol engine and there are fewer
parts to have to worry about. If properly looked after,
a diesel engine will keep on going with little maintenance
required.