Parallel Hybrids

[P-hack]

well, "need" is a funny word. They had money for it, but while dual clutch is fashionable these days, with the advent of electronic controls I have to wonder if a computer shifted sliding mesh (as opposed to constant mesh) transmission might be feasible as well, they are more efficient than the ubiquitous constant mesh since only one pair of gears need to be meshed at a time. But they stopped making them in the 1930s as they had the name "crash box". A computer that knows exactly when the teeth are lined up *should* be able to make precision shifts with the push of a button (or automatically) and/or tweak engine speed to rpm match. More info on various types: The Gearbox (Transmission)


Also there is an IEE paper (I have not read) that states:
" It is obvious from the presented results that the parallel hybrid powertrain features better fuel economy than the series one for the applied test cycles, whereas both hybrid powertrain concepts feature the best fuel economy at light-duty application."
IEEE Xplore - Analysis of Energy Conversion Efficiency in Parallel and Series Hybrid Powertrains

I cannot think of one "advantage" that series has over parallel, except being able to simply recharge the batteries at a stop (which means you are "idling", so stop that), and reduced mechanical complexity.

The main disadvantage of series, well many hypermilers can outperform hybrids just using a stick shift, in the city especially where there is a lot of accelerating (i.e. load). As well as all the conversion losses to get any power to the wheels. In fact these losses necessitate a larger engine in the series than a parallel, as well as more losses charging and discharging the batteries in the hopes of recovering those losses by pumping more fuel into the engine to get a better bsfc. And still a parallel can use the same strategy while the car is moving, if it pans out, using the rotating motor as a generator.

The engine absolutely should have a means to power the wheels directly (and efficiently), no exceptions, it makes sense in the city and the hiway. "Mostly parallel" is the way to go if you are relying on fuel.

[IamIan]

To me , terms like 'series' , 'parallel' , 'full' , and 'mild' as qualifiers .. and as a simplifier to describe a variety of different vehicle configurations ... are themselves counterproductive terms.

Especially when people try to then also apply those 4 terms in some type of hierarchy of A always better than B kind of thing ... full hybrid is not automatically better than or worse then mild hybrid ... series hybrid is not automatically better than or worse than parallel hybrid ... but, that's just me.

As they say ... 'the devil is in the details' ... and those 4 terms do not define the systems enough in order to determine which one may perform better or worse , under some also yet undefined conditions.

So I personally don't like using any of those.... but , that's just my own personal preference... to each their own.

[freebeard]

The safe term to me is 'through-the-road hybrid'.

I picture a reverse trike, with a V-twin like a Morgan but with front-wheel drive and an in-hub electric drive in the rear.

Can anything else touch that?

[niky]

Add pedal power to the rear.

Which reminds me... What happened to the tribrid trike?

[GreenHornet]

Originally Posted by freebeard

The safe term to me is 'through-the-road hybrid'.

I picture a reverse trike, with a V-twin like a Morgan but with front-wheel drive and an in-hub electric drive in the rear.

Can anything else touch that?

This is the same architecture that the XR3 Hybrid utilizes and yes is very efficient especially with the small tractor diesel motor up front. You can also utilize a front engine rear wheel drive with an inline electric motor to serve the same purpose.

GH

[NeilBlanchard]

Well, it does get really complicated with both the Prius and the Volt, which I would say have to be called multi-mode hybrids. They can function as serial and parallel and both at the same time, too - and in EV mode.

I do think that we need to be able to distinguish between serial and parallel hybrids.

[GreenHornet]

Neil you are correct it is very tough to distinguish and really you can not as they are true hybrids in a sense taking the best of both worlds serial and parallel and wrapping them into one with the usage of clutches and electronic control. For the do it your self kind of guy the serial is a straight forward and simple approach to hybridization but one could argue so is the parallel if you are taking Honda IMA approach or GM E-Assist belt style. In my opinion the easiest would be the GM approach it would also most likely be the most cost affective as well as you only need 1 motor/generator.

[freebeard]

GreenHornet -- Almost exactly. The XR-3 design calls for a belt drive motor. I'd want to completely re-body it though. I know the diesel would be more efficient, so I invoke the Scuderi split-cycle as an option.

The Blackjack Zero is similar, has the Moto-Guzzi V-twin option and could adapt an in-hub motor in the rear.

[IamIan]

Originally Posted by NeilBlanchard

I do think that we need to be able to distinguish between serial and parallel hybrids.

To each their own ... But I disagree.

For me at least ... I think the time spent debating ,... or even initially learning / teaching about what is or is not a serial hybrid and why , or a parallel , or a mild, or a full ... etc... that same time spent learning how it actually works pros and cons ... will have gotten 'us' further ahead ... than debating about which one of 4 words to label it as.

And if we already learned how it actually works ... pros and cons ... than we would be further ahead than any of those labels could ever hope for ... and thus they could be skipped entirely... and we would be further ahead without them.

I think 'we' are all better off , when 'we' instead spend the time to learn a bit about how the systems actually work , including it's pros and cons ... and not trying to shoe horn all of mechanics , engineering, and science down into 1 of 4 words.

I don't see the one word label adding understanding to people ... I see it only serving as a barrier to actual understanding... and encouraging inaccurate or incorrect hierarchy assumptions... and more than once I've run into people who end up getting confused about how those 4 words are used in other fields , which don't always use them the way some people use them when talking about hybrids... which in itself is a negative effect of the effort to shoe horn it all down into one of those 4 words.

At least that is how I've seen it ... maybe other have seen it differently.

[GreenHornet]

Originally Posted by freebeard

GreenHornet -- Almost exactly. The XR-3 design calls for a belt drive motor. I'd want to completely re-body it though. I know the diesel would be more efficient, so I invoke the Scuderi split-cycle as an option.

The Blackjack Zero is similar, has the Moto-Guzzi V-twin option and could adapt an in-hub motor in the rear.

Hey freebeard,

Ya I purhcased those plans when they first came out and was never really a fan of the looks of the XR3. However I thought they did a great job on the plans and are a huge improvement over the older Quincy Lynn plans they offer which I have most of. The plans are definitely thought provoking and gives you a glance into what a scratchbuilt 3 wheeled diesel hybrid takes to build.