EVs Are Great Around Town, But.......

[Angel And The Wolf]

Originally Posted by jray3

\https://insideevs.com/explained-mits...xtender-story/
Karmann Eclectric: Gettin Rangy
https://karmanneclectric.blogspot.co...rangy-ier.html

Thanks, JRAY! I look forward to reading your blogs.

[redpoint5]

Originally Posted by jray3

pushers can be simple, extremely effective, safe and stable to tow, and if used only for occasional long highway trips, deliver greater overall lifetime mpg than a hybrid with or without a plug.
A gentleman who is not active online but probably the most accomplished EV pusher EVer is currently en route to my place on his semi-annual rental property inspections from Utah to So. Cal. to B.C. Canada and back, all done with an aircooled VW engine pushing his RAV4 EV!

My second pusher trailer (and first one built from scratch by me) has recently finished engine resurrection and installation (pulled from a Karmann Ghia totalled in a 1995 collision)!
Karmann Eclectric: Gettin Rangy
Some of the high school auto shop kids on this project had never dealt with points or a carburetor before, let alone valve adjustment.. I'll try to report back after road testing, which is due to happen in the next two weeks.
https://karmanneclectric.blogspot.co...rangy-ier.html

What kind of fuel economy is the guy with the RAV4 getting? I'm curious what you end up getting too.

I highly doubt a pusher can get higher lifetime fuel economy than a plug-in hybrid with normal usage patterns. A Prius gets 50 MPG when being used as a "pusher". The Prime goes 30 miles on a charge, and a Volt about 50. A pusher could never be as safe and easy as a hybrid.

Pushers sound neat to me, and I'm happy people experiment with them, but it's never going to be a solution for the masses. It doesn't solve a problem that hasn't already been solved in other more convenient ways.

[jray3]

I completely agree with redpoint5 that pushers will never be a solution for the masses, in keeping with the majority of solutions that we promulgate here on EcoModder. My first aircooled VW pusher got a hair over 20 mpg while pushing, and so does my buddy's, right on par with a heavily-laden aircooled VW. A modern ICE drivetrain, esp a diesel should do much better. The equation for lifetime mpg is simple. My pusher usage is under 3% of miles, but let's round up to 5% to maximize the gasoline consumption. My i-MiEV annual miles has hovered at 19k, but I'll round that up too, to 20k to reflect more pushing.
Using the common "Volt driver equation" of gallons burned/miles travelled, if I push for 1000 miles per year, or 5% of 20,000 miles, that would yield 50 gallons over 20,000 miles for 400 mpg.

A road warrior like my RAV4 buddy who lives in a tiny rural town but visits distant places pushes for more like 10,000 of his 20k miles per year, for 500 gallons burned in 20,000 miles, or 40 mpg. That extreme example is past the crossover point for a hybrid or Volt. (Energy-wise, but not based on finances at the time of purchase, and probably not even today if trading the RAV for a Volt.)

Now if we wanna throw electrons into the oily equation, my i-MiEV is rated 112 mpge. Driving 19000 miles at 112 mpge and 1000 miles at 20 mpg yields the equivalent of 219.6 gallons burned in 20k miles, an average of 91 mpg, still waay over a conventional hybrid scenario, and better than most Volts if you peruse https://www.voltstats.net/. Of course there are Volts with many thousands of miles per tank of gas, but I'll submit that those folks bought some very expensive insurance....

HowEVer, much of this discussion of electric versus gas miles is moot anyway because of the electricity used for gasoline extraction and refining that is rarely included in such discussions. At the Nissan-claimed 8 kWh of electricity consumed per gallon of gasoline produced, an ICE has already consumed 39 miles worth of EV driving power before it EVen starts burning. Any gasoline-fueled vehicle getting less than 39 mpg would be using more electricity than a typical EV! However, opinions are varied as the facts are unavailable on this highly proprietary refinery data that the Federal EIA no longer reports, combined with the facts that even the electricity used in refineries varies according to the cost of grid electricity versus the mix of end-products desired and the current grade of crude oil being input. Here in Washington state, our gasoline is largely refined using electricity produced by hydropower! Going further, if we consider oil from tar sands, the electric advantages point skyward in a hurry, as the energy required to simply liberate that oil from the ground runs between 20% and 34% of its total energy content...

[oil pan 4]

The pusher design I outlined would probably do around 30 mpg.

[Vman455]

Originally Posted by jray3

Some of the high school auto shop kids on this project had never dealt with points or a carburetor before, let alone valve adjustment.. I'll try to report back after road testing, which is due to happen in the next two weeks.
https://karmanneclectric.blogspot.co...rangy-ier.html

Hey, SHS! My entire immediate family (and myself) are graduates.

[jray3]

Originally Posted by Vman455

Hey, SHS! My entire immediate family (and myself) are graduates.

Small world- gotta love it. The SHS Spartan now rides an electric chariot in place of an old diesel Gator, but otherwise we're still in the ICE ages.

[jray3]

Originally Posted by oil pan 4

The pusher design I outlined would probably do around 30 mpg.

Great! What'd you design? I mainly used stuff that was laying around waiting to be scrapped, plus I love the irony of it; specially at car shows!

[oil pan 4]

Originally Posted by jray3

Great! What'd you design? I mainly used stuff that was laying around waiting to be scrapped, plus I love the irony of it; specially at car shows!

A minimalist single wheel 25 or 26hp air cooled engine with a single fixed speed belt transmission that fits the standard trailer hitch. Kind of less is more.
I didn't design the whole thing just an outlined some of the specifications.
I would probably put in a 40kwh battery before I did that.

[cajunfj40]

Hello all,

So the topic, if I understand it correctly, is to have a battery-biased hybrid vehicle, where the ICE is sized only just large enough to push the vehicle down the freeway at peak BSFC, and is hopefully removeable completely ("modular hybrid") for the much larger quantity of miles that are to be driven well within battery range.

Obviously, any hybrid is going to be a compromise, in that you'll be carrying extra weight/complexity around, and thus not be as efficient as an optimized EV-only or ICE-only vehicle. Driver ability, weather, usage patterns and location will influence the point at which either of those two poles do or don't make sense - and that point will also vary based on what metric(s) is(are) being considered. Best miles per ton of CO2 emitted vs. best miles per dollar vs. best miles per gallon of oil pumped, vs. best number of dollars per year, etc. Diesel manual pure ICE may emit the absolute least amount of CO2 per year, but not everyone can drive perfectly do do that and at some point the trips are too short for a given weather region to get good longevity out of the engine without preheat. Heated garages, shore-power block heaters/cabin pre-heaters, etc. use power and at some point charging an EV or plugin hybrid instead starts to beat it.

Starting at the EV-only end of the spectrum, at what point in "don't drive outside of battery range most of the time" does it make the most sense to borrow/rent/hire an efficient ICE car for those few out-of-range drives, and then at what point does having only a plugin hybrid like a Volt or Prius make more sense? I'm leaving out non-plugin hybrids and pure ICE vehicles as being out-of-scope. Somewhere on this spectrum is where the "modular hybrid" comes in. I'm just not sure where, except for hobbyist/enthusiasts that want to do something neat/different - which is of course a completely valid reason to do it.

For a "modular hybrid", the "Pusher" architecture neatly sidesteps a lot of system integration hassles. An ICE Pusher can charge the host EV "through the road" - the EV just "feels like it is going downhill all the time". Angel And The Wolf's idea of connecting the engine to a retrofitted rear differential is probably lighter than a standard Pusher, at the expense of more fabrication and more "unneeded weight" when not lugging the engine around. I would imagine a weight-distributing hitch would do the job of getting sufficient traction on Pusher drivewheels if going the usual way.

If the dismountable engine is being mounted directly to the EV to drive a pre-integrated driveline, major bonus points for making it look like an outboard motor off a boat instead of a funny-looking generator on a cargo rack. Some Honda outboards use the same engine block as a Honda Fit, btw...

[redpoint5]

I've said it before, but a pusher is mostly a solution in search of a problem, even if a neat one.

The BMW i3 gasoline engine is puny. You won't notice the difference in weight or performance much. It accomplishes alleviating range anxiety with a minimum penalty in weight and complexity.

It would be neat to see a pusher capable of outputting slightly more than needed to maintain steady cruise, such that it can slowly charge the battery. Get enough charge back into the battery, and you could assist the pusher on uphill climbs and acceleration events with the electric motor.