Where does the energy go?

[oneinchsidehop]

Originally Posted by rh77

I like the idea of a loco-type hybrid as well, but I recall someone having a good argument against it at some point.

The only concern I have with hub-mounted motors is where they're located -- if too far outboard (in the wheel) you're adding unsprung weight...

RH77

Mount them inboard like the brakes on some F1 cars.

[oneinchsidehop]

Originally Posted by 2TonJellyBean

Makes me think that hybrids are really made wrong. They should have full electric drive and the ICE should only power a generator - like a locomotive (except with a plug in powerpack in between).

The motor/generator could then be much smaller in displacement and run ONLY at the RPM where it gets peak efficiency. Furthermore, it frees up different packaging options, especially with hub mounted drive motors that also do regen braking.

Yes, they are made wrong. If they really made them right their core products would look like crap, and they wouldn't have the next years "improvement" already developed.

They are in the business of selling cars, not providing the best car available.

[trebuchet03]

Originally Posted by 2TonJellyBean

Makes me think that hybrids are really made wrong. They should have full electric drive and the ICE should only power a generator - like a locomotive (except with a plug in powerpack in between).

The motor/generator could then be much smaller in displacement and run ONLY at the RPM where it gets peak efficiency. Furthermore, it frees up different packaging options, especially with hub mounted drive motors that also do regen braking.

So that's a series hybrid setup -- it works, but there's a critical drawback.... You want to generate only a little bit more than what is needed - so you want an engine sized accordingly. So you're going to install an engine that generates near to peak power at an optimal rpm.

Your traditional ICE doesn't live at peak power for long periods of time - it typically hangs out around 10-20% power while cruising (which will be most of it's service life) with the occasional short (relative) burst at full power. So, we can expect the 5,000 or so hours our gasser IC engines are designed for.

So, optimize fuel economy -- smallest engine possible making near to 100% power. This engine will fail way too soon Locomotives get around this by using over sized engine (way over sized). This is just fine for them due to scale - so taking the FE hit isn't as big of deal given their load size. Locomotives get mighty inefficient when they're not hooked up to cars :/ If we apply this same principle to a small operation -- we end up with similar sized engines (that is, our FE minded engine), with more components with a very similar max FE

A perfect example comes from generators -- small engin'd fast spinning (typically under 4Krpm) generators don't last long (we're talking 200 hours, maybe). But slow spinning (~1800) generators with larger engines have a service life in the thousands of hours range...

That's not to say there's no one is trying to make this happen

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That's why mass produced hybrids on the road today are neither series nor parallel -- they're a combination of both. You know, use a differential backwards and such


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As for hub mounted motors..... That's a LOT of unsprung weight -- not to mention, you really can't optimize a hub motor as rpm and torque requirements vary significantly

[GasSavers_Erik]

I agree that typical engines will fail in short order if ran at 100% capacity, but what we need is some design changes in these small engines. Larger bearing surfaces/crank journals and better balancing will go a long way to extending engine lives.

Many motorcycle engines get ran hard for a significant amount of their lives and still hold up reasonably well.

A smaller mass produced engine (eg. 2 cylinder or even a well balanced 1 cylinder) should be cheaper and lighter to install/remove.

In the last 10 years Koeler has began been making pressure lubricated (with spin on oil filter) over head valve riding lawnmower engines as low as 13hp.

I think we are getting closer to small ICE's that can run run near 100% with reasonable durability. Then they will just need to develop the computer controls and fuel injection systems to make these small engines highly efficient.

[2TonJellyBean]

Anyone remember where the Honda Goldwing engine originated from?

[theclencher]

Originally Posted by rh77

I like the idea of a loco-type hybrid as well, but I recall someone having a good argument against it at some point.

RH77

yeah, it was after psycho tried to tell me the chevy volt was a loco-type hybrid, and it ain't (locomotive= no batteries). then i went on to question the wisdom of that set-up, or even one with batteries, for automotive application. engine>genset>controller>motor>wheels or engine>genset>batteries>controller>motor>wheels hasta be a less efficient energy conversion than engine>transmission>wheels.

[2TonJellyBean]

D'oh!!! Good one! L

The flat 4 was designed to be a generator motor... sorry, thought that the funny given the topic.