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P-hack · 06-30-2013, 08:22 AM

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.

06-30-2013, 08:22 AM	#21 (permalink)
P-hack Master EcoModder Join Date: Oct 2012 Location: USA Posts: 1,408 awesomer - '04 Toyota prius Thanks: 102 Thanked 252 Times in 204 Posts	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.