Joe1199

been looking at information about gotech mfi and was wondering if someone could explain what batch firing for the injectors means. does this mean all four injectors fire at once and if so how does this not ruin economy and emissions by fuelling a cylinder/cylinders that are not on a firing stroke?
cheers
joe

fonfe

the rs2000 16v uses batch firing, basically what it is is injectors 1&4 fire together and 2&3 fire together. lets say cylinder 1 is on induction so both injectors fire (4 fires to a closed valve) when 4 is on induction 1&4 fire again but this time 1 is to a closed valve. on WOT (wide open throttle) all injectors fire at the same time

flashpoint

in reality It makes very little difference weather you batch, sime-sequential or sequential injection systems. remember escort re turbo is effectively batch firring anyway

sas

Just for ref, I ran batch fire on my ZVH which got it to 166.6mph.

S.

pa_sjo

You get better atomisation and emissions when running (a properly mapped) sequential setup.. but for the kinda stuff that goes on around here, it doesn't really matter (fiesta turbos are also batch-fire).. anything with a cam sensor is sequential (eg, zetecs).. I'm surprised the RS2000 engine isn't sequential! Learn something every day...

fonfe

so was i! was a bit taken back when i realised the only timing sensor was the crank sensor!

tabetha

Batch firing is when all FOUR fire together, ONCE EVERY ENGINE REVOLUTION.
Escort Rs Turbo is spraying a fine mist all the time not squirting there is a massive difference, and this is done every degree of rotation not just a few degrees.
Cylinders 1+4 and 2+3 firing together is NOT BATCH, it is SEMI SEQUENTIAL.
SEQUENTIAL injection is where the fuel is injected according to the inlet valve position, each injector fires in turn ONCE every engine CYCLE.
tabetha

fonfe

well according to this:
http://www.motec.com/definitions.htm

Semi-Sequential Fuel Injection - Semi-Sequential means that 2 or more cylinder's injectors are triggered at the same time, but only 1 time during the engine's cycle. This requires the ECU to be synched with the engine's cycle. Typically injection timing is retarded from the optimum timing point for full sequential by an angle which is equal to 1/2 the angle between 2 cylinders in crankshaft degrees. On a V8 Chevrolet, the injectors for cylinders 1 and 8 would be triggered at the same time. They would be triggered 45 degrees late for cylinder number 1 and 45 degrees early for cylinder number 8. Degrees between 1 and 8 = 90 ; 1/2 of 90 = 45. Semi-sequential allows optimization of injection timing which typically leads to increases in midrange torque and a reduction in fuel consumption for equivalent power compared which Batch fire.

Batch Fire - Batch fire means that 2 or more injectors are triggered at the same time once every crankshaft revolution. If the ECU is synched with the engine's cycle, the injection timing can only be half optimized as fuel is injected both on the intake stroke and on the power stroke. Companion cylinders are paired in batch fire mode similar to wasted spark ignition modes. The advantage of batch firing is that the ECU needs only to know where TDC is. This means that a sync on the cam is not required. The disadvantage to batch firing is that the Injector Dead Time is doubled for the engine's cycle. This leads to a decrease in fuel flow and typically requires a larger, less efficient injector to be used to make up for the loss of flow. On High Horsepower applications this means the idle quality will suffer tremendously.

fonfe

so after reading that it would make the i4 16v engine batch fired as the injectors 1&4 and 2&3 are triggerd twice not once as in semi-sequential surely?