2000 Polaris Virage TX, SLX, Pro 1200, Genesis, Genesis FFI Personal Watercraft Service Manual, Page 277Get this manual
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FFI1M FUEL INJECTION Theory FFI 1M Combustion Process
The FFI1M combustion process functions in two modes: stratified and homogeneousThe engine is started in homogeneous, idles in stratified, then smoothly transitions again to homogeneous as the engine moves to higher RPMFor more detail on FFllM combustion, see Introduction to FFI Fuel Injection video, PN 9915680During startup, fuel is injected with the piston low in the cylinderAirfuel is mixed by turbulence, and multiple plug firings occur to ensure quick starting and complete combustionDuring idle, multiple plug firings continue for each cylinder combustion eventSpark is timed to occur as fuel reaches the spark plug tip, then is programmed to continue in multi-strike modeDue to fuelair density at low RPM, and fuel actually spraying on the plug tip, repeated plug firing ensures complete combustionAt higher RPM, the fuel injectors supply fuel earlier in the firing sequencePistons are farther down the cylinder, and airfuel is mixed by turbulenceIn this mode the mixture is more combustible, so fewer firings per combustion event will occurVery low amperage is required to sustain either stratified or homogeneous operation Stratified: AirFuel mixture is layered with different ratios within the combustion chamberHomogeneous: AirFuel mixture is uniform throughout the combustion chamber