You want room, you're getting room. Buick Velite 6 for China previews new GM approach to electric cars
yea - even as someone here was saying they are shying away, & heading more towards EV. What caught my eye in the article was this; "new architecture" ... ok - GM is word smithing imo, saying in essence 'they' haven't made an ICE/BIG battery platform - careful not to claim they're the 1st. welcome to the party GM, glad to see you copy the Chrysler Pacifica plug-in platform ... roomier traction pack holder. The question now - who if any other manufacturer will follow these two. New approach? Yea new to them. Will it make it to the US? Hard to say - China is the new #1 plugin car buying market. .
The architecture of the volt really was developed over 20 years ago and a better idea was displayed in the 1998 detroit auto show as the ev-1 parellel hybrid. A new architecture was badly needed as car designers have learned much over the last couple of decades, and lithium battery packs are a lot more design friendly than the nimh packs the original design was based upon. IMHO the bmw i3 architecture of a skateboard battery and rear engine seems a better solution. That ev-1 parellel hybrid had a 75 hp diesel in the rear to drive the rear wheels, now I guess a 1.5L 150 hp engine would be more likely (see engine in the volt).
To be honest naturally aspirated diesel is as cheap as a gas engine and properly controlled more efficient and reliable than a turbo diesel. The 1 liter 3 banger diesel from a Daihatsu Charade only weighed about 40 lbs more than the 993cc gas counterpart but delivered much better economy. That is what I would like to see in a range extender, even better would be a flexboost diesel dual fuel where you had CNG or e85 direct injection along side diesel to add horsepower and better emissions.
The idea of matching an Atkinson (extended cycle) to propel a hybrid gives roughly the same efficiency, with easy emission control. Diesel is still adequate for industrial applications, not passenger cars.
After the no hybrid comment, I don't see this coming to the US at this time. A BEV version will be following a year later. You note the emission problem of diesel. Adding CNG or E85 to it is as complicated as just adding the current diesel emission controls. For an EV range extender, cost and packaging are important considerations; possibly more important than efficiency. A CNG or E85 engine that is designed to take advantage of those fuels' high octane is a simpler, cheaper solution. Atkinson produces less power. Depending on application, it may have too high of a space cost. Take the i3 REx for example. Its Otto cycle engine produces enough power to maintain a steady 75mph on flat ground without pulling from the battery. Atkinsonize it for better efficiency, that top speed drops. and so does the rate it can charge the battery. There isn't any space for a larger engine.
Actually the i3 REx has a 647cc Otto engine delivering 25kw. If we scale down the Prius c Atkinson engine (1497cc, 55kw), would need 680cc to cope with that max power. Can't see much difference here.
We see toyota's most efficient engine the 2L dynamic force for hybrid produces 180 hp. Now toyota said their pi+di system has trouble naturally aspirated bellow 0.5L size but ... a 2 cylinder 1L version with a iron block and aluminum heads would be quite tiny and produce 90 hp (67 KW). The iron block would likely make it as small as the bmw rex engine and cost less since the heads and injectors are on a much higher volume engine. If weight is your thing instead of size, nissan has a 1.5L 3cylinder that only weighs 40 kg (88 lbs) this would be more expensive, but grab 3 of the cylinders and the weight would be lower than many passengers for a 135 hp 3 cyclinder engine. No problem with atkinson for power if it has di to keep revs down and compression up at higher power levels. I went with the newer dynamic force instead of the prius c engine because 41% peak efficiency versus 38%, more power to weight, larger efficient band of power levels.
But changing engine size for power output isn't that simple. When not derated for the i3, that engine produces 45kW. The little rotary from the A1 e-tron concept was purpose built for a series PHEV. It put out 15kW with 254cc, and two would likely fit in the i3. The reality is that cost is going to be a major factor. The engine in the i3 REX and gen1 Volt was not ideal because the budget was spent on the EV side(and body for the i3). Even when more can be devoted to the engine, I foresee them(Toyota) sticking to older technology for the lower cost when it comes to longer EV range PHEVs.
Actually a higher rpm would sustain the power output without changing the size of the REx. My plan is to cobble a cooled exhaust recirculation system and measure the change in fuel consumption. Bob Wilson
