What is the difference between a petrol engine and a diesel engine?
2007-06-11 11:23:48 · 16 answers · asked by Paul R 1 in Science & Mathematics ➔ Engineering
If you ain't sure which is which, don't smoke!
2007-06-11 19:14:48 · answer #1 · answered by billtheangler 5 · 0⤊ 1⤋
Don't start the car as there a diesel fuel pump is finely machined and petrol does not have the lubricating qualities. The basic difference between petrol and diesel is the burn rate a petrol engine uses a spark for ignition as the fuel is very volatile but a diesel engine has a higher compression ratio and uses the bicycle pump on the end of the thumb theory. By doing this it heats the combustion chamber up too about 600 degrees centigrade and diesel will self ignite at 400. You get away with running a leaner mixture with a diesel as the chemically correct (stoichiometric) fuel ratio for a petrol is 14.7:1 and its 100:1 for a diesel
2016-04-01 02:29:37 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Petrol is a light, low boiling temperature, petroleum distillate with a low ignition temperature. It generally needs a spark plug to give the ignition in a petrol engine.
It also has a much higher vapour pressure than Diesel.
Diesel is a much heavier compound, also from petroleum but, these days it is also being produced from bio-oils.
Petrol engines have a lower compression ratio compared to diesel. A pre-mixed petrol/air mixture is drawn into a cylinder, compressed and ignited by the spark plug.
Diesel has a high ignition temperature, has a higher density than petrol, it has a higher boiling temperature and a low vapour pressure. The compression ratio is also much higher.
Ignition in a diesel engine takes place by 'Compression Ignition'.
Air is first compressed by the engine to a high pressure that increases its temperature to the ignition point of the diesel.
At this point the diesel is injected into the compressed air and 'auto-ignition' takes place.
Both engine use the 'OTTO' four-stroke system of operation.
Intake ---Suck
Compression---Squeeze
Ignition----Bang
Exhaust---Blow.
2007-06-11 15:49:25 · answer #3 · answered by Norrie 7 · 0⤊ 0⤋
Petrol is the British term for what Americans call Gasoline.
Diesel fuel is named after the inventor of the Diesel engine.
Petrol is used in "Spark Ignition" engines.
Diesel fuel is used in "Compression Ignition" engines.
Both engines use the basic 4-cycle approach...
1.Intake
2.Compression
3.Expansion
4.Exhaustion
The spark ignition engine ignites the fuel/air mixture with a spark plug just prior to the end of the compression stroke.
The compression ignition engine has a longer compression stroke that results in the fuel/air mixture igniting itself without a spark. The temperature increase created by the compression ignites the fuel/air mixture on its own.
Advantages of Diesel:
1. MORE EFFICIENT. (longer compression/expansion, lower RPM)...thus better fuel economy.
2. MORE TORQUE at low speeds...better for towing heavy objects.
3. DURABILITY...well designed Diesel engines last much longer...especially since they run at lower speeds.
Disadvantages of Diesel:
1. LOWER POWER. Diesel engines cannot run at as high RPM as Petrol engines. Power = torque * RPM and petrol engines have peak torque at high RPM...resulting in higher power for equivalent size engines. New technologies have reduced this issue.
2. NOISY. New technology has limited this issue but older diesels were very noisy.
3. EMMISIONS. Older diesel engines put out high levels of solid particulates that result in smog. This is especially true when poor quality diesel fuel is used that is high in sulfur. New diesel engines in advanced markets don't have this problem.
2007-06-11 14:12:29 · answer #4 · answered by Flyer 4 · 1⤊ 0⤋
A petrol engine runs on gasoline and a diesel engine runs on diesel fuel. they are both combustion engines but operate on different types of fuel.
Diesel is "a hydrocarbon mixture, obtained in the fractional distillation of crude oil between 200 °C and 350 °C at atmospheric pressure"
Petrol is "produced in oil refineries. Material that is separated from crude oil via distillation, called virgin or straight-run gasoline, does not meet the required specifications for modern engines (in particular octane rating; see below), but will form part of the blend".
2007-06-11 11:29:02 · answer #5 · answered by Lady Geologist 7 · 0⤊ 0⤋
A petrol engine uses a spark plug to ingite the fuel/air mixture. A diesel engine uses compression to ingnite the fuel/air mixture.
2007-06-11 11:26:55 · answer #6 · answered by dogsafire 7 · 1⤊ 0⤋
In an internal combustion engine, petrol is ignited by a spark plug, whereas diesel's explosion is caused only by the pressure in the combustion chamber.
2007-06-11 13:37:27 · answer #7 · answered by Awesomeness in a box 1 · 1⤊ 0⤋
petrol is thinner than diesel and requires more electrics to make it work deisel needs compression to fire and petrol needs an ignition spark to fire
2007-06-11 11:34:11 · answer #8 · answered by Anonymous · 0⤊ 0⤋
Petrol is refined petroleum. Diesel is not as refined and can be made out of biofuel.
2007-06-11 11:26:42 · answer #9 · answered by artsy_lovely_lady 5 · 0⤊ 1⤋
1. One is cheaper than the other
2. If you use either in the opposite type of engine your car won't be happy
2007-06-11 11:27:30 · answer #10 · answered by masonv80 3 · 2⤊ 0⤋
"Petrol" is gasoline, diesel is kerosene. Two different fractions of crude oil, with way different properties.
2007-06-11 11:58:43 · answer #11 · answered by medicine wheel 3 · 0⤊ 1⤋