Throttle input techniques to maximize efficiency

5441 Views 33 Replies 21 Participants Last post by rmay635703, Mar 17, 2017

Mr.Woolery

Discussion Starter · Mar 15, 2017

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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21 - 34 of 34 Posts

ampera_jed

· #21 · Mar 16, 2017

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!)

bjrosen

· #22 · Mar 16, 2017 (Edited)

ampera_jed said:
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.

hellsop

· #23 · Mar 16, 2017

llninja said:
Ari still used pump and glide, shifting to N, and it wasn't exactly in circles, more like rectangle at FedEx field (washington redskins). I've given up hypermiling. I now just drive and don't worry about braking any land hypermiling records.

Close to a circle!

Like a giant roundabout with an ornamental building in the middle.

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Barry

· #24 · Mar 16, 2017

Most of the hypermiling advice in this thread corresponds very well with the green ball display on the dash. I guess the Volt engineers got it right.

Personally, I drive with the flow of traffic for safety and time efficiency, both of which are more important to me than saving a kWh. I also think that slowing down other drivers while in an EV is being a poor ambassador for the technology. Beating them at stoplights is a better demonstration of the capabilities.

jbakerjonathan

· #25 · Mar 16, 2017

rmay635703 said:
<snip>

I have achieved 68-72 miles ev range all summer using the above techniques on a 2013
Slow and steady wins

Wow! I have a late model 2014 with the 17.1 kWh battery and the best I have done with the battery was 59.2 miles - no gas. The temperature was around 78 degrees and tires were at 43 psi. The terrain was flat. Speed varied from 30 mph to 45 mph and I controlled my speed using CC.

My best range for both battery and ICE was on a 104 mile trip with temps around 63 degrees, same tire pressure, where I obtained 55.3 miles on battery and 51.1 mpg on the ICE. The terrain was flat. Lots of slow driving.

KenC

· #26 · Mar 16, 2017

So, you're still in the honeymoon phase when you're learning the limits of the vehicle.

Surprised that your Volt's range estimate is only 51miles after averaging 5.36miles/kWh. In theory, you could have gone 75 miles at that level of efficiency. That should have raised your range estimate the next day. Perhaps it was a cold night and cold start in the morning. That affects the estimate was much as how you drove the prior few days. When it's Summer here, and I'm getting 5+miles/kWh, my range estimate increases to the high 60s.

ampera_jed

· #27 · Mar 16, 2017

bjrosen said:
Why do you think people here don't know what they are talking about?

The two potential answers to that are "I didn't suggest I think that" and "They aren't talking about the OP's question".

bjrosen said:
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.

That's baloney. It doesn't give that sort of information at all. In no way is the instrumentation either that accurate, or capable of recording what sort of driving conditions that particular drive encountered or what average speed that driving covered.

We're talking about literally 10's of Wh difference here between accelerations, and you're trying to tell that from a readout in 0.1kWh resolution, which itself is a calculation of the battery capacity based on an algorithm from several possible sources, some of which will be self-inferred assumptions about how power drawn affects the battery capacity.

Roostre

· #28 · Mar 17, 2017

My commute is 41 miles each way. I take the highway in the morning as it is early and traffic free plus mostly downhill. Going home its secondary roads and stoplights, mostly uphill.

The biggest single variable is a steep 3 mile hill that is marked 60MPH. Traffic flows at 60-70 along here most days, but if I can set the cruise at 55MPH or "get stuck" behind slower traffic I always make it home on battery. IF I go faster and keep with traffic there is no way I can get home on battery.

Taking the hills slower is the biggest gain I've found. My commute is at the edge of what Gen1 can do without burning gas everyday.

O'Dell

· #29 · Mar 17, 2017

I've been using the "pulse" method of driving, mild acceleration and coast, ever since my old Prius days. It really became effective with my C-Max Energi and Gen 2 in electric operation.

ttchybrid

· #30 · Mar 17, 2017

19KW is the sweet spot! Once you've depleted battery and your in ice mode, the next time you come to a stop, throw it in nuetral and it forces ice off.

Now when you accelerate way and keep it under 19KW your ice will not turn on for a while. I've driven up to 4km this way before ice turns on again

Norton

· #31 · Mar 17, 2017

Throttle input techniques to maximize efficiency....

= Drive slow so you can save enough on the electron costs to buy yourself a beer on Friday.

Or: Drive it as quick as you like and enjoy yourself all week long.

Pincher or Not-a-Pincher: Your call !!!

hellsop

· #32 · Mar 17, 2017

KenC said:
Surprised that your Volt's range estimate is only 51miles after averaging 5.36miles/kWh.

If that happens four days in a row, it'll show. Only doing it once will have only moderate impact on the meter.

hellsop

· #33 · Mar 17, 2017

ttchybrid said:
19KW is the sweet spot! Once you've depleted battery and your in ice mode, the next time you come to a stop, throw it in nuetral and it forces ice off.

Now when you accelerate way and keep it under 19KW your ice will not turn on for a while. I've driven up to 4km this way before ice turns on again

You don't want to force the ICE off. It's rebuilding the buffer charge it's going to use when you start again. The car knows what it's doing.

rmay635703

· #34 · Mar 17, 2017

srmarti said:
To me that's the sort of "hyper miling" stuff that annoys and endangers others. Around here even driving the posted limit P.O.s some drivers. I just more or less drive "relaxed" remembering I'm on a public road and not a race course.

I will tell that to the next Amish buggy and farm tractor I pass in the middle of the highway.
Daily occurrence around here.

I'm sure my volt is much less safe and much more dangerous than the oversized farm equipment blocking the road going 5-10 mph

Occasionally there is one going 25.

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