Cylinder Shutdown

[bronco9588]

Is squirt capable of shutting down fuel injectors to save gas while cruising? I have a v8 and recognize that i will have more than enough power to drive my vehicle at half its power. Any thoughts or suggestions?

[Andy_Stprbeck]

I think MS can control two banks of injectors with independant maps, so you could arrange the banks of injectors and the two maps to do what you want maybe?? I think it's not allowable for the pulse width of the "off" cylinders to go to zero though, so that may be the hangup. Also, probably would be tricky to get the transition from some cylinders being "off" to normal opperation to end up smooth, since the off cylinders would have to go from completely off to completely on to avoid super lean problems, you would end up with a sudden jump in power. Not sure how OEM's handle that, maybe with electronic throttle control???

[SQLGUY]

The problem I see is that, IIUC, when one of those 8-6-4 engines shuts off cylinders, it also locks open the exhaust valve(s) so as not to be dragging the unused cylinder(s) through intake and compression cycles. That requires mechanical changes and actuators to support them.

[bronco9588]

Id figure work in for compression would yield work out for the "combustion phase" and intake/exhaust would be nearly the same as well.

[Laminar]

Not quite, you typically see a lot of frictional losses as well as valvetrain losses. I've tested a 4 cylinder diesel engine on an engine dyno, and it required about 37 lb-ft of torque just to keep the crank rotating when the fuel injection was stopped. Obviously this is going to be significantly less if you're only losing two cylinders and you're on a smaller engine, but the only way to really know if it will work is to try.