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Throttle input techniques to maximize efficiency

5438 Views 33 Replies 21 Participants Last post by  rmay635703
In your experience, is it more efficient to give short bursts of relatively higher throttle/kW output levels with coasting in between, or to "hold" the throttle longer at lower thottle/kW levels to maintain a certain speed?

I've been experimenting with trying to maximize my efficiency & range during my commute. It's ~18 miles one way, all surface streets and fairly level (few small ~5ft hills here and there), with speeds seldom exceeding 45mph. Pretty ideal conditions for the Volt and for experimentation with efficient driving. Under normal acceleration from a stop up to cruising speed, I'm generally keeping the throttle input at ~20kW or less.

One method I've used for maintaining cruising speed (let's say, of 35-40mph) has been to maintain a steady throttle input somewhere between 8-15kW, depending on conditions. Another method has been to use short 3-4 second bursts of 18-20kW throttle inputs to nudge the car back up to cruising speed after coasting (anywhere from 5-15 seconds, depending on conditions) and losing 2-4mph of speed. Under both experimental conditions, I'm maximizing use of coasting wherever possible.

I'm still on the fence as to which is more efficient, though I'm leaning towards the "burst" throttle method as being more efficient since I'm guessing that 20kW @ 3sec is less than, say 10kw for 6+ seconds. The main drawback of the burst method being that the ride is less smooth due to the oscillation of acceleration & coasting compared to the "constant" throttle method.

Any thoughts on your experiences?

Side note regarding efficiency: My Volt is still "learning" what the estimated range per charge would be as I've only had the car for a month now. For example this morning, it was estimating range of 51 miles after a full charge. I used 3.3kWh for my 17.7 mile commute (pretty average, my best so far has been 3.0kWh for the same trip), and the range estimator says I still have 38 miles left.
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Gentle acceleration, hold the speed steady, keep the speed down (K=1/2MV^2 i.e. energy is the square of the velocity), coast to slow down, use regen paddle if coasting isn't sufficient, use the brake only for the final stop.
My habits changed when I got the Volt, I drive it to maximize EV range. It has nothing to do with costs because in my case electricity is more expensive than gas but in either case vastly more economical than by old car which had a Hemi. I just prefer the electric motors over the engine, I don't like the noise the engine makes. If the Volt had a 100 mile electric range I wouldn't obsess over it but the 53 mile range (which I can frequently stretch to 60) is on the hairy edge for many of my local trips. One of my frequent trips is 29 miles each way if I take a back road but is 37 if I take a highway. If everything goes right I can do the round trip on battery but on several occasions I've missed it by a block which is pretty frustrating. Other trips such as into Boston are about 50 miles, if I do things right I can get to a garage with an EVSE with a few miles to spare, unfortunately on the return trip I generally miss by a mile (I'm guessing it's an uphill vs downhill thing).
I'm curious why people feel equipped to post their opinions on how they drive, when they have clearly always driven like that and always will, rather than comparing and contrasting their experiences when using the two different approaches?

Is it an internet thing?

Someone says 'Can you tell me your experiences of A versus B?' and the answers almost always are 'I only do A, and it's really good. best to do A'

Just interested in 'internet psychology' here of how people prefer to offer their opinion than answer a question. (I might well be guilty of it myself!)
Why do you think people here don't know what they are talking about? The Volt is well instrumented to give you feed back on your instantaneous energy use which means that anyone who so desires can get some pretty good experimental evidence about what works and what doesn't. In addition there are some well known aspects of the Volt's engineering which would lead you to certain conclusions about optimal driving styles, I'm thinking specifically about the two different motors in the Gen2 Volt. In the Gen1 Volt GM used two identical and expensive electric motors, but in the Gen2 they replaced one of the motors with a less expensive and less efficient motor. The second motor is only engaged if you need extra power so if you want to maximize efficiency there is a benefit to keeping the power requirements down which is why gentle acceleration is preferred. Other advice is based on basic physics.
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