Electric pusher

[Ron22]

Possalby a dumb idea., I have alot of them.
Would it be possible to build a "trailer" with an electric motor and batteries? Have it geared for the freeway (60-70MPH) using as small of motor as possible just to maintain speed. Then use my CRX engine to get up to speed. Once at speed turn off the gas engine and turn on the electric motor. I could even use the trailer to continue the rear sloop of the CRX. The weight of my CRX HF is less than 2000lbs.
Am I wrong that it takes most of the power to get the weight moving and up to speed?

[thisisntjared]

that all depends on how fast you plan on going...

[MetroMPG]

I wondered about something like this (except for urban use) when I wrote this article:

All I want for Christmas is a plug-in hybrid pusher trailer

[Ron22]

I saw the one you talked about MetroMPG but it was the opposite of what I was thinking. Yours was for around town mine is for freeway. Most the others I saw when searching were for electric cars and most of the time it seemed they were to just charge the batteries .

[MetroMPG]

I think you'd have a hard time making an electric pusher trailer for highway use because energy demands are so much greater at highway speeds.

Unless you have a source of advanced batteries (nicads or li-ions & associated management / charging), the trailer would have to carry too much lead to make it practical.

[Bill in Houston]

People usually think in terms of "electric car, gasoline pusher" because of range considerations.

I sort of get where Ron is going in that with a small car he could cruise with maybe 11 hp of electric power. Whereas for driving around town, 11 hp would be pretty low.

To me the issue is that in town you only need propulsion for short bursts, while on the highway it is a constant long-term demand. Of the two following scenarios-
1-30 hp electric car with 20 hp gas pusher for the highway
or
2-50 hp gas car with 20 hp electric pusher for the highway
-it seems that the one with the electric pusher would end up needing more batteries/weight. BUT, it could still be a useful rig. I need to think about it some more.

[Ryland]

how about just a smaller gas engine pusher? something direct drive? if I was to do an electric pusher I would want it for in town, regenerative breaking, stop and go trafic.
in talking to owners of electric vehicles, they all say that they try to stay off the highway as much as possible because it kills their range.

[MetroMPG]

That's an interesting idea Ryland.

As for max range for DC EV's, I'd guess it's probably at the lowest constant speed in a gear where motor RPM is roughly 3000.

The reason the Milburn & Baker electrics from the early 1900's had such long ranges (50-60 miles) is because their max speeds were 20 mph, so average speeds were even lower than that

[Ron22]

Originally Posted by Bill in Houston

People usually think in terms of "electric car, gasoline pusher" because of range considerations.

I sort of get where Ron is going in that with a small car he could cruise with maybe 11 hp of electric power. Whereas for driving around town, 11 hp would be pretty low.

Yes that was my thinking. I would realy only need to gear the motor for one speed and could use as small of motor as posible.

To me the issue is that in town you only need propulsion for short bursts, while on the highway it is a constant long-term demand. Of the two following scenarios-
1-30 hp electric car with 20 hp gas pusher for the highway
or
2-50 hp gas car with 20 hp electric pusher for the highway
-it seems that the one with the electric pusher would end up needing more batteries/weight. BUT, it could still be a useful rig. I need to think about it some more.

Since I already have a 60 HP car I was leaning for option 2

[rh77]

I've thought of something similar on-board (to turn the rear wheels on a front-drive car).

The trailer looks to keep it simple regarding the drive mechanism.

Concerns:

How stable is a pusher-trailer with a single pivot point at 60 mph? Highways here are pretty lumpy and have undulations, especially before and after bridges.

I do quite a bit of high-speed driving (cannot be avoided -- schedules to/from the airport and no light rail YET). To work and back, the speeds are slow enough with congestion to help with drag considerations.

However, a gasoline/diesel or CNG/LNG-powered pusher (either on-board or trailer-bound) is intriguing. Have alternative fuels been considered? The 5th wheel idea has been implemented (on-board vehicle pusher), but seems complicated with an added suspension component.

I have plenty of room in the hatch area for such extra equipment. How would an on-board generator feeding electric traction motors in the trailer work? (more of a serial design such as a locomotive). The trailer would need some weight for traction. Further, on brakin, could they be turned into juice to charge the ICE's batt for restart? Ahh, the possibilities...

RH77

[ffvben]

I've seen the pusher on a show that aired around earth day. it had a electric pusher and a bio diesel vw car. I don't remember the name of the show, it was 1hr show where this guy used only bio diesel to charge his fleet of electric cars as he traveled a long route. or he might just use hydro power for another show and geothermal and so on. It was a neat show i just wish i could of recorded all of them, i guess ill have to wait till next earth day.

[Ron22]

RH77
You are a little ahead of me. My plan was to try a trailer first if it worked I wanted to add it into the rear of my CRX to drive the rear wheels.
Would a 10 HP diesel be any better than my CRX engine?
Question is still how much HP does it take to keep my CRX at 70MPH?

[Ryland]

if I remember right, to keep a vehicle going 65mph, was something like 15 horse power, so I would think that a 15-20hp diesel engine pusher might be the way to cruse, haveing the engine running at 80% of peek, with a direct drive.
if you look at the HP rating on an electric motor used for electric cars, the numbers tend to be rather low, like 10-15hp, because their power curves are rather straight, unlike a gas engine that has to rev up rather high to get it's high HP numbers.

[Bill in Houston]

Originally Posted by rh77

I've thought of something similar on-board (to turn the rear wheels on a front-drive car).

I have thought of this as well. Converting a 4wd vehicle to run on the original gas engine in the front, and something else in the back. Something like a Justy or 4wd Civic or Tercel wagon. It seemed like having the original rear diff in there already would make things a lot simpler.

If the rear were powered by an electric motor, then it would be great to somehow incorporate regen as well.

[rh77]

Originally Posted by Bill in Houston

I have thought of this as well. Converting a 4wd vehicle to run on the original gas engine in the front, and something else in the back. Something like a Justy or 4wd Civic or Tercel wagon. It seemed like having the original rear diff in there already would make things a lot simpler.

If the rear were powered by an electric motor, then it would be great to somehow incorporate regen as well.

I thought about this quite a bit yesterday, and didn't condiser a vehicle with a diff already in place -- great idea!

The hardest part was getting the power to existing structure in the 'Teg...would it be: a 5th wheel, a tire that rolls against a rear tire, pusher trailer, etc. It looks like I'd have to get a project car to try something like this...

I also wasn't sure if generators came with cats, or if one could be retrofitted -- if not, would it really help emissions?

RH77

[Bill in Houston]

To me, a pusher trailer seems like the simplest way to try out something like this. I vote for a really good kill switch in case something comes loose...

But for a daily driver, something integrated seems like it would be more manageable.

I'd vote for avoiding a generator if possible. If you push with electric, carry batteries. If you push with gas/diesel, use a direct drive. But that's just me.

[rh77]

Originally Posted by Bill in Houston

To me, a pusher trailer seems like the simplest way to try out something like this. I vote for a really good kill switch in case something comes loose...

But for a daily driver, something integrated seems like it would be more manageable.

I'd vote for avoiding a generator if possible. If you push with electric, carry batteries. If you push with gas/diesel, use a direct drive. But that's just me.

Yeah, a loose trailer, while comical (if you picture it busting loose and wreaking havoc) can nevertheless be dangerous.

The concern that I have is the cost and weight of a good set of batts.

So, does a serial-hybrid design have high parasitic losses? I'm thinking of a locomotive design: on-board generator with a power cable to the trailer. For those not familiar: How a Locomotive Works. While the ICE is off, it can also provide power for an electric brake-assist, lights, blower, etc.

I'm sure the simplest design of the electric traction motors would have a single gearset, which would limit it to power-assist in town or cruise-assist at highway speeds.

I'm really thinking about what I can do with the existing platform: the Integra. I'm not aware of any rear diff that would bolt on for that design (it would have to be a costly custom).

Bill - in your case, since the Element is available as an AWD or FWD, tihs would be a perfect swap. I hear with the Subaru drivetrains, the center diff gets jumbled-up without the rear axle attached. The best situation is likely to take an FWD vehicle that has an AWD/4WD rear axle twin that you can swap so it's truly independent of the front transaxle.

I'd need to search around for cheap FWD/AWD models of the past that would make a great project. The first that comes to mind is the Diesel Tempo (make the front Bio-D). During that production period FWD or AWD was available (the gasser had the same option and is more common, but still rare overall). A standard Mistu Lancer might handle an '03+ Evo rear end (but costly, unless the old ones abroad are available...)

RH77

[Ron22]

For a rear diff Honda did have 4WD Civic wagens back in the 80's. I am really want to try the idea with a trailer before i even got into trying to fit it all in one car.

[Bill in Houston]

Originally Posted by rh77

So, does a serial-hybrid design have high parasitic losses? I'm thinking of a locomotive design: on-board generator with a power cable to the trailer. For those not familiar: How a Locomotive Works. While the ICE is off, it can also provide power for an electric brake-assist, lights, blower, etc.

I think that serial hybrid does have high losses. Even if the generator is 90% efficient and the motor is 90% efficient, you'd lose 19% of your power. I think that is higher than most ordinary transmissions.

I'm sure the simplest design of the electric traction motors would have a single gearset, which would limit it to power-assist in town or cruise-assist at highway speeds.

Right, a concession to simplicity and low cost. The Rabbit pusher was pretty cool and all, but it had an automatic transmission, which I would want to avoid.

I'm really thinking about what I can do with the existing platform: the Integra. I'm not aware of any rear diff that would bolt on for that design (it would have to be a costly custom).

A trailer seems like a better fit for the Integra.

Bill - in your case, since the Element is available as an AWD or FWD, tihs would be a perfect swap. <snip>The best situation is likely to take an FWD vehicle that has an AWD/4WD rear axle twin that you can swap so it's truly independent of the front transaxle.

Definitely. Just sitting here at my desk, it seems pretty simple. :-)

I'd need to search around for cheap FWD/AWD models of the past that would make a great project.

Over time, I bet there have been lots of FWD/AWD models that we aren't even thinking of. The challenge would be to find the rear end for cheap, it seems. I had not even thought of the Tempo...

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