The one that can’t be done!!!
Over the years I have had many enquiries about the Mitsubishi GDi engines and autogas. I must admit if you look at the list of vehicles that have been fitted with the GDi engines its little wonder, there’s a lot of them out there. The big manufactures of LPG systems are working on direct injection systems, but it would seem that the GDi is not to be included. You can see why, they are going to concentrate on the latest, newest vehicles, to receive the most longevity from there systems.
So, why are direct injection engines so different to convert from any other engines?
Well the answer is quite simple. A direct injection engine has the petrol injectors fitted directly into the cylinder chamber of the engine, rather than in the inlet manifold. This is mainly done to reduce emissions and also to improve MPG. There are lots of articles out there to explain why this is, such as
http://en.m.wikipedia.org/wiki/Mitsubishi_GDI
So I wont bore you with it here!
The main problem is that if you convert the engine to run on LPG, there is no longer petrol running through the petrol injectors. This causes the injector to over heat and eventually, the tip melts and the injector stops working. The answer would be to still inject a small amount of petrol through the petrol injectors to stop them over heating, whilst mostly running on LPG.
Sounds simple enough but if it was that easy everyone one be doing it right!!? Well yes, they would and no it isn’t that simple, mainly because the petrol system works at some ridiculously high voltages and pressures. Which does complicate things somewhat!
Any way, some month’s back I purchased a Mitsubishi Space wagon with a 2.3ltr GDi engine as a project vehicle and after much scratching of heads, much gathering of information and readings. Then doing the whole lot again with electrical engineers, I think we are almost there.
September this year should see the beginning of the road tests.
So I will keep you updated from here on in!