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todayican 12-19-2010 02:12 AM

Time over & under 40 mph?
Im curious about something, it goes to how to "spec" my hybrid drive system.

How much time to people spend driving over 40mph and how much time under 40mph.

The gauge in the Beemer says my average speed overall is 46.6mphId imagine that that factors all "car running but not moving" time.

If you'd like to answer, it would be a huge help if you said the normal use of the car IE "I drive 15 miles to work with this car, and thats about it" or I'm on the highway on an overnight trip at least 3 times a month".


user removed 12-19-2010 10:40 AM

46.6 is a fairly high average speed. My last 2k miles has been about 38-39 MPH. I am fairly sure it used distance versus time the engine is running to make the calculation, so if you are stopped the clock is still running.

In winter here this car is my sole means of transportation. My trips are usually 20 or more miles average up to a max of 100 locally. Occasionally I will take a road trip of 300 to 400 miles total.

Higher average speeds tend to reduce the effectiveness of hybrid power trains as far as mileage.


RobertSmalls 12-19-2010 11:44 AM

You actually want to compare DISTANCE traveled over and under 40mph for your calculations.

If you grab the spreadsheet linked here, you'll notice that for the LA92 + EPA FTP drive cycles that it uses, 7% of the distance traveled is over 60mph, 25% is over 50mph, and 40% is over 40mph. The data is from

My own commute? It's 2mi in an urbanized 35mph zone, 4mi in a PSL 45 where I can go 50mph, then 3 mi in an awful village with PSL 30. Then there's time I spend coasting down to red lights and stop signs. The ScanGauge says it's 22mph average, but I'll characterize it as 38mph distance-weighted average.

todayican 12-19-2010 12:03 PM

Thanks guys, that confirmed my suspicion that im the highway bound holdout lol.
(outside of 2 mile trips locally, everything is down the interstate for me)

RobertSmalls 12-19-2010 05:20 PM

People are far more receptive to data that confirms their suspicions than that which contradicts. People usually make bad scientists and engineers.

I didn't mention the other half of the miles I put on my car a year. Some of it is running errands around town at low speeds, and much of it is rural interstate at 70mph.

todayican 12-19-2010 05:27 PM

Perhaps telling why I wanted to know would help ;-)

Im playing with the configuration of my hybrid.

The Diesel's main role is to serve as a highway speed only motor.

I have some decisions to make with regard to the rest:

1 option would be to build a 10kw pack and "trust" that all of my non highway speed running would be covered on a single charge (Because the gearing of the diesel would render it of little help for speeds under say 50)

option 2 would be to have a seperate gen to recharge the pack while driving (based on the answers above, seems like a needed thing)

One option which I am quite in the dark on is to use a regen scenario on the main drive motor while its being "driven" by the diesel.

Need to do more research on option 3 :-)

Frank Lee 12-19-2010 05:53 PM

Ask 10 people that question and you'll get 10 different answers. You have to look at your own route(s).

euromodder 12-20-2010 12:01 PM


Originally Posted by todayican (Post 210269)
(outside of 2 mile trips locally, everything is down the interstate for me)

In that case, in order to get a 46mph average, you'll be spending a lot of time well over 40mph.
If I hit 46mph average, I usually have spent around 3/4 to 4/5 of the distance on the motorway.

Is the hybrid system worth it when it's only going to be used on short local trips that don't make up too much of your distance ?
You'll have to carry it around all the while.

todayican 12-20-2010 12:07 PM

For me the use of a hybrid system is as much about optimizing the 2 power sources as it is being an EV

The EV drive line will weigh about 200lb in the trike and should yeild an electric only range of about 50 miles. It will be capable of the full range of speed between 0mph and 70mph

The diesel alone will not. It will have only a centrifigual clutch and one gear rendering it useful only for speeds of 50 to about 75

So on the one hand I think of the ev stuff as a "transmission" for the diesel (that happens to be able to drive the car for 50 miles at a clip ;-)

NHRABill 12-21-2010 10:30 PM

Average speed in my wifes car (She has the gauges) we are lucky to break 30mph over the coarse of a full tank of gas.

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