[COLVERT]

Originally Posted by Mike Noc

Mixtures are very important in petrol engines but irrelevant in diesel engines. They aren't air throttled so take in the maximum amount of air on each induction stroke. The mass of air will vary depending on heat, density and how hard the turbo is working, but it will always be the total of whatever is available, so at idle there is loads of excess air in the combustion chambers.

There is no mixture like you get with petrol, the fuel burns on a flame front as it is injected.

OH, Mike I am truly sorry about disagreeing with you about diesel mixtures but I have to. I hope I don't offend you in any way and you treat these posts as an argument to obtain factual information and not a put down from one person to another.

The mixture ( the ratio of air to fuel.) Constantly varies in a diesel engine due to the governance of the ECU.

The input of air, as you say, remains maximum to the requirements of the engine. In order to produce power according to the throttle pedal position the ECU will vary the amount of diesel into the mix. The richer the mix the greater amount of power produced by it.

It's because of this function by the ECU that so much more power and thus MPG can be produced by the engine for a specific quantity of fuel. ( ie one gallon for instance. )-- Ignition timing of course also plays an important part in this better economy too. ( There are a number of small additional things that help too. )



Wheeew. Here endeth todays sermon.---( Well it is Sunday after all. Lol. )



Whooops. I forgot to say------the total of air used will be the amount being processed at any given time and not the total of air available which can be far greater. ( dependent on the velocity of air in the input duct at any given time. )