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Ask Datatek he clearly knows! On a petrol engine you have the stoichiometric ratio of 14.7 to 1 air to fuel by weight. Air is regulated by the butterfly! Yes? Then the correct amount of fuel is added! Yes?
A diesel sucks in as much air as it can at all times because it has no butterfly (that's not what the ILT is for!) then fuel is injected depending mainly on throttle position. Think basic pump! This esentially is just changing the idle speed! As you add fuel you do not automatically add more air (in a petrol you have to) yes if it's turboed more will go in but think normally aspirated for this. The fuel is just using the air that is already going through because it is totally unregulated! For each downward stroke of the piston atmosphere will always attempt to fill it whatever the speed of the engine! Whatever the injected quantity!
On a petrol you have manifold vacuum because the throttle closes stopping the cylinder charge entering! On a diesel you dont get a vacuum because it's never restricted!!!!
That do?
If you don't get a vacuum in the manifold of a normally aspirated diesel what sucks the air in? Do i take it you have never worked on a diesel fitted with a throttle valve then?.
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