You’re right that a diesel engine works differently to a petrol engine.
In a petrol engine, the petrol is ignited by a spark. In a diesel engine, air is squeezed to a much higher pressure than a petrol engine, which increases the temperature of the air to hundreds of degrees Celsius. The diesel is then injected, and ignites (starts to burn/combust/explode) because of the high temperature of the air.
So it is not pressure that makes the diesel burn, but the high temperature of the air in the engine. But it is squeezing the air to high pressure that raised it to that temperature.
Now, if you’re going to ask why the temperature of air increases when you squeeze it, that’s a whole other question…
Great question – real life stuff that can be answered by science! yay.
Edward has given a great answer! Diesel is squirted into the combustion chamber just at the right time when the air within that chamber is under enough pressure that the diesel will explode.
This is because as the molecules within the air are pushed closer and closer together (under pressure) they move faster and faster, as they are repelled by the other molecules. The faster the molecules move, the higher the temperature gets. Then… when a fuel like diesel is injected into that mix, it is so hot it explodes.
Hi bencraven
You’re right that a diesel engine works differently to a petrol engine.
In a petrol engine, the petrol is ignited by a spark. In a diesel engine, air is squeezed to a much higher pressure than a petrol engine, which increases the temperature of the air to hundreds of degrees Celsius. The diesel is then injected, and ignites (starts to burn/combust/explode) because of the high temperature of the air.
So it is not pressure that makes the diesel burn, but the high temperature of the air in the engine. But it is squeezing the air to high pressure that raised it to that temperature.
Now, if you’re going to ask why the temperature of air increases when you squeeze it, that’s a whole other question…
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Hi bencraven
Great question – real life stuff that can be answered by science! yay.
Edward has given a great answer! Diesel is squirted into the combustion chamber just at the right time when the air within that chamber is under enough pressure that the diesel will explode.
This is because as the molecules within the air are pushed closer and closer together (under pressure) they move faster and faster, as they are repelled by the other molecules. The faster the molecules move, the higher the temperature gets. Then… when a fuel like diesel is injected into that mix, it is so hot it explodes.
0