http://forum.mazda6tech.com/about4213.html



the mazdaspeed 6 is using a "high pressure" fuel system (your pressure washer is higher), and its got the injectors right on the head.



wondering if you couldnt just put the injectors in the trailing plug hole or something?



they look like normal injectors, but are deigned to work at a higher pressure (1700psi), and are controlled electronically.



if you look the fuel pump is controlled just like the rx7's, and the msp6 low pressure fuel pump is in the tank, and the high pressure pump is external, on the head.

 

I've been wanting to do that for a couple years now. I met a guy at the PRI show who owned a shop on the East coast who was working on it...

 

I guess in a rotary that would let you use really high compression and boost, because you don't introduce fuel until you're ready for combustion, is that it?

 

i guess the piston engine can run lean without detonation because theres a nice rich mixture around the spark plug, and then the surrounding is just air, which acts as an insulator

 

Thats the idea behind diesel engines. Direct injection in gas engine allows for leaner overall air/fuel ratio because the fuel is concentrated around the spark plug. Its done primarily for efficiency.



I think the idea is especially suited to a rotary due to the large quench areas and poor combustion chamber shape. But I see spark timing being especially critical with a direct engine rotary because the combustion chamber moves across the spark plugs.

 

yep, fuel and spark timing might sorta get linked together.

 

I have recurring visions of putting CIS type injectors into the oil injection bungs in the fuel injected 13B rotor housings. The fuel should atomize on contact with the hot rotor face.



You need to investigate the new Volkswagen direct injection engines. 11:1 compression and absurd amounts of boost in the turbo cars, and compression in the 13:1 range in the naturally aspirated models. Stratified charge at its finest, and they are only scratching the surface.

 

put injectors in the trailing plug holes....

 

thats what i was thinking

 

i would think the rotary would run into problems with complete combusion/mix because the rotor face is SO long compared to face of a piston. but some one should try it and please prove me wrong . it would really not be that hard to do if you had a ECU that gave FULL control over injection/ignition timing and width.