How to accelerate in P&G mode?

[theholycow]

Originally Posted by sonyhome

I not RPMs, flooring the accelerator, the injector duty cycle is close to 100%. So there's a max amount of gas in the piston. Is the explosion complete (gas fully used)? Is there always enough oxygen for the amount of gas pumped in the piston?

The computer won't let it run that rich. I have never managed to see more than 50% duty cycle. At low RPM, flooring it doesn't increase the duty cycle much vs. partial throttle. If I am light on the gas at a given RPM I might see 8% duty cycle, and if I floor it I might see 12%.

Originally Posted by R.I.D.E.

When you use engine drag (car in gear) you are turning all fuel to the injectors off=DFCO=Decelerate Fuel Cut OFF.

Coasting is great, but if you have to stop or slow down a lot, it may be better to use DFCO. AS long as you can keep engine speed above 1000 RPM you have no fuel delivered to the injectors.

If you need greater acceleration use a lower gear. If you don't need greater acceleration, use the highest gear that you possibly can. When you want to maintain speed use the highest possible gear as soon as practical.

Quoted just to reiterate. That was very well said. I would replace "may be" with "surely is".

Try this. use a lower gear than you would use normally. Once you reach the point where more throttle really doesn't do much of anything, you have reached the best point for economy. Wot will use more fuel than this method. The ideal throttle percentage should be about 70%, could be less but not much more.

Are you talking about your Honda in specific, or all cars? From actual measurements, I can tell you this is not universal. In my VW, injector duty cycle goes down when I go from 80% (maybe 70%, maybe 90%, my foot is just not that accurate) to WOT. I'm at a loss to explain it. At first I thought maybe the fuel rail pressure goes up at WOT, allowing a shorter duty cycle to feed in more fuel; but I can't argue with the gas pump, and using WOT (instead of that 80% target) has improved my FE.

To determine what RPM your enigne stops fuel shut off, just let off the gas in 5th gear and wait until you feel the surge when the fuel supply returns.

Also, note that the surge is barely perceptible, you really have to be looking for it, at least in my vehicles. It is gentler than, for example, the torque converter locking in my truck (which itself is almost impossible to feel).