It’s been 10 years since I first drove a Toyota Prius at a Toyota press event. And just this past week, Chevrolet announced the pricing of its much anticipated Volt. In the interim a number of companies have produced a plethora of hybrid cars and trucks. While I personally think hybridizing SUVs, truck, and large sedans is a ploy to add a few tenths to the manufacturer’s CAFE rating, I strongly believe that it’s useful to hybridize ‘C-class’ and smaller cars. The type of cars that represent the bulk of sales in Europe.
The Prius is a best selling hybrid (and the first volume production hybrid in the American market). It is optimized for city cycle fuel economy but still relies on its internal combustion (IC) engine to directly power the front wheels at speeds over residential street speed limits. Toyota’s parallel hybrid system allows the car to be driven in electric motor only mode (about 30 or so miles per hour) and uses a start/stop capable Atkinson cycle engine powering the front wheels directly.
When you really need to get on it, the electric motor can supplement the IC engine (but make sure you’re using non-slip soled Birkenstocks and don’t expect ‘getting on it’ to mean M3 levels of acceleration). But you can’t run it on battery at all urban speeds (up to 45 MPH or so) and you can’t run it on battery for an extended period of time (it doesn’t have a big enough battery pack and it just gained a plug-in option).
The Volt, on the other hand, never drives the wheels directly from its IC engine, rather it uses the engine as an electrical generator. Think, the Hammerhead-i Eagle Thrust that Top Gear built.
Now that’s not really fair to GM whose Volt is really well engineered. The Volt is closer to a true electric vehicle than the Prius. But its design is optimized toward urban driving, the extended range option may make it feasible to use for longer journeys, but . . .
Why Chevy decided not to drive the wheels directly from the IC engine is known only to the engineers and GM brass. However AutoBlogGreen has a real good article speculating on why GM did what they did to the Volt.
Where does that leave BMW and its i100 and sibling hybrids? I suspect BMW will build plug-in hybrids that can be used in urban/suburban areas at speeds up to 50 or so MPH on electric motors only. They can be recharged overnight using the power grid, since they will see the bulk of daily duty in populated areas. As long as you’re not a hoon, you may run on the electric motor for almost all of your urban driving.
But since it’s a BMW it’ll have to go like stink on the open road. The Vision EfficientDynamics showed a 150 HP 3 cylinder diesel motor supplemented by the electric motors when needed. There will be a ton of torque and, as Carroll Shelby said, ‘horsepower sells cars, torque wins races’. That car, as stunning as it was on the outside was even more
beautiful on the inside, under the covers.
The constraints I believe are operating on BMW, which lead me to conclude that this is the direction they’re headed in, are as follows: Urban congestion and pollution taxes are on the rise in European cities and will spread worldwide in time. Most families will not have more than one car (the two car plus household is a unique American phenomenon) and because its a single car per family it will have to fulfill multiple roles. Weight savings are as important as anything else a car maker can do but weight cannot be saved at the expense of compromising safety. And safety standards will continue to be more difficult to meet.
BMW will introduce more cutting edge electronics, more new materials and manufacturing processes, and they will continue to build state of the art propulsion systems. Batteries, electric motors and carbon fiber will be the keystones, and we know about their recent announcements regarding two of those items (batteries and carbon fiber). Our mission is to gather as much info as we can on BMW’s take on electric motors.[To Be Continued]