City driving econ: Faster accel in lower gears vs. Slower accel in higher gears?

[cRiPpLe_rOoStEr]

Originally Posted by Logic

So it has a normally open throttle valve just to charge vacuum powered ancillaries during overrun and braking/ (free power)

AFAIK the brake booster is the only vacuum-powered device on most (if not all) modern cars.

I can see it getting hydraulic pressure to actuate, from the same pump that actuates the VVT, but, at a guess I'd say there's a torque sensor or 2 in the drive-train somewhere that picks up torque coming from the wheels and/or flywheel during overrun..?
Probably a braking sensor, involved in decisions to..?

I don't know how the electro-hydraulic actuators of the intake valves work, but the throttle plate is entirely electronically-controlled and actuated.

And most newer cars have electronic throttle pedals, regardless if gassers or Diesels.

[Grant-53]

A few years ago BMW did a study that indicated 3/4 throttle acceleration was optimal. Also note that slow acceleration will affect traffic flow and the traffic signal operation algorithm.

[Piwoslaw]

Originally Posted by Grant-53

A few years ago BMW did a study that indicated 3/4 throttle acceleration was optimal. Also note that slow acceleration will affect traffic flow and the traffic signal operation algorithm.

Sounds close to the 80% load I heard about a while ago.

[cRiPpLe_rOoStEr]

Having learned to drive in a car without a tach, maybe relying on some random arbitrary pedal-based measure could be simpler, yet sometimes it doesn't work in real-life driving. I remember so many times hitting the pedal to the floor while the Opel Corsa B struggled to keep RPM before I had to shift to a lower gear...

[Mcgiiver]

#2) Go up the initial hill in 1st gear all the way or #3) Try to go up in 2nd as soon as as possible with my foot to the floor. (It's a moderate climate, so "cold" engine is just a relative term.)

IMHO, #2 would be best, but not with the engine screaming in 1st. #3, foot to the floor is never good. Warm up idle creates negative MPG and should not be used.

#3) option of leisurely acceleration with lower load through all the gears until reaching 4th or 5th would use the most fuel.

IMHO, #3 is the way to go, it will not use the most fuel.

[Mcgiiver]

#2) Go up the initial hill in 1st gear all the way or #3) Try to go up in 2nd as soon as as possible with my foot to the floor. (It's a moderate climate, so "cold" engine is just a relative term.)

IMHO, #2 would be best, but not with the engine screaming in 1st. #3, foot to the floor is never good. Warm up idle creates negative MPG and should not be used.

#3) option of leisurely acceleration with lower load through all the gears until reaching 4th or 5th would use the most fuel.

IMHO, #3 is the way to go, it will not use the most fuel.

[cRiPpLe_rOoStEr]

Sure the slope of the hill would dictate the correct gear to start driving. And maybe with some clutch kicks as a last-resort attempt to prevent the engine from stalling while trying to climb with a taller gear, not only fuel consumption would increase but also wear and tear.

[bandit86]

Simulate acceleration, if you got a easy scan, try going up a hill in higher gear and then try the same Hill at the same speed in lower gear. That should tell you if you recall has better fuel economy one way or another which could be better optimized.

[JRMichler]

There is an older thread on the best way to drive up a hill: https://ecomodder.com/forum/showthre...ear-23957.html. Plenty of good information from several people in that thread.

[bandit86]

We could maybe try this with an electric car, using a watt meter. Accelerate from standstill to 35 miles an hour and drive 100 ft and measure amount of watts used. Although now that I think about it we don't have the transmission gearing helping