Direct and indirect injection

Dion,

That is not entirely true, although it is true on older indirect injection, modern indirect injection technology has improved significantly.
Craig,
What Dion explained is correct to a certain extent, indirect injection diesels are not THAT bad, the reasons why passenger cars are mostly indirect injection is as follows:
Direct Injection engines are noisier due to detonation but produce more power and require little if any preheating for cold starting.
They produce more power and therefore require heavier components making the whole engine heavier, they were also more expensive to build.
Indirect injection technology does not mean a smoky engine, a direct injection can smoke just as much if the injectors leak or the pump has been tampered with....
The differences are:
In a direct injection engine, the head is flat and the combustion chamber and swirl are in the piston, the injector sprays straigh to that chamber.
In an indirect injection the pistons are flat and the chamber and swirl are in the head, the injector injects to that chamber.
It is horses for courses and the reason why direct injection is becoming more popular in smaller diesels is cost and technology, with the aid of electronic controls they can now make them quieter.

Will