Diesel Versus Spark Engine Ignition

As you may already be aware of, diesel engines are 
more efficient than gasoline engines of the same
power, resulting in much lower fuel usage.  For an
efficient turbo diesel, the average is 40% more miles
per gallon.  The higher compression ratio with 
diesel engines help to raise efficiency, but diesel
fuel also contains around 15% more energy per unit
volume than gas.

Diesel engines that are naturally aspirated are far
more massive than gasoline engines of the same power
for two reasons.  First, it takes a larger capacity 
diesel engine than a gas engine to produce the same
amount of power.  Essentially, this is because the 
diesel can't operate as quickly.  The rev limit is
slower, because getting the correct fuel to air ratio
into a diesel engine fast enough is more difficult
than a gas engine. The second reason is due to the
fact that a diesel engine needs to be stronger to
withstand the higher combustion pressure needed for
ignition.

Diesel engines also produce very little carbon 
monoxide as they burn the fuel in excess air except
at full loading capacity, where a full quantity of
fuel is injected per cycle.  They can however, 
produce a black soot from the exhaust, which consists
of unburned carbon compounds.  

Often times, this is caused by worn injectors, which
don't atomize the fuel sufficiently enough, or a 
faulty management system that allows more fuel to be
injected that can then be burned with the available
air.  

For commercial use that requires towing, diesel 
engines tend to have more desirable torque.  Diesel
engines tend to have their torque peak quite low
in their speed range which provides smoother control
over heavy loads when starting from rest, crucially
allowing the engine to be given higher loads at low
speeds than a gas engine.

The lack of an electrical ignition system in diesel
engines improves the reliability.  The high durability
of diesel engines is also due to the overbuilt
nature as well as the combustion cycle, which will
create a less violent change in pressure when 
compared to a gasoline type spark ignition engine.
Diesel fuel is also a better lubricant than gasoline,
so it is less harmful to the oil film on piston 
rings and cylinder bores - making it routine for
diesel engines to go 250,000 miles or more without 
having to be rebuilt.

For several reasons, diesel proves to be better than
spark engine ignition.  Diesel engines last a lot
longer, they offer more torque, and they are also
more reliable.  They are also more expensive as well,
although you get what you pay for.  If you have 
never owned a diesel vehicle, you owe it to yourself
to see everything they offer you - and you'll find
yourself a very satisfied customer.

(word count 463)

PPPPP