![]() MPFI systems can only add fuel during the intake stroke of the piston, when the intake valve is open. ![]() By moving the injector into the combustion chamber, GDI (gasoline direct injection) gains a few advantages over the previously discussed systems.īy putting the injector inside the cylinder, the engine’s computer gains even more precision control over the amount of fuel injected during the intake stroke, further optimizing the air/fuel mixture to create a clean burning explosion with very little wasted fuel and increased power delivery.Ī GDI system also has more flexibility regarding when in the combustion cycle the fuel is added. ![]() Direct injection takes this evolution to the next level by placing the injector inside the combustion chamber. What are the advantages DI of over the old SFI system? Antuan Goodwin (engine writer for Cnet) said that readers may have noticed that during the jumps from carburetion to SPFI (single port) to MPFI (multi-port), the point at which fuel is added to the intake charge, has moved from before the throttle to the intake manifold and onward to the individual intake runners - closer and closer to the combustion chamber. Sequential fuel injection has been used in marine engines for several years and is the system that is currently used in most new towboats and the system PCM used on engines until 2016.ĭI (Direct Injection) is the next evolution of fuel injection where the fuel is injected after the intake valve directly into each cylinder at over 3000 psi. This system was way more fuel efficient and created way more power than the carburation systems it replaced. This air/fuel mixture is pulled into the cylinder past the intake valve on the intake stroke of the piston and is then compressed and ignited. Each of these injectors puts fuel into the system at 30-40 PSI before the intake valve. Here is some basic information about injection systems.īasically, a SFI (sequential fuel injection) system has a fuel injector for each cylinder. Sequential Fuel InjectionĮver since PCM came out with the new direct injection H5 and H6 engines, we have been asked what the difference is between direct and sequential injection and if PCM is the only company using direct injection.
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