That’s my idea of a hybrid EV! It’s the model diesel electric locomotives have used for decades. The generator operates at its most efficient speed unlike typical car motors.
OK, I’m wondering what “delivery vehicle” needs a 500 miles range. Given then they start fresh every morning, they could be refueled and recharged overnight every night and be good to go for the next day.
Seriously, who needs a 500 mile range for a delivery vehicle ?
I don’t really understand the power trains of the different types of hybrid vehicles. Please explain how the power train of this vehicle differs from other hybrid vehicles.
Thanks,
Wendy
The diesel electric locomotives have large, powerful electric motors on the wheel axels themselves. It is really neat to see if you ever get the chance. The train is driven ONLY by the electric motors. The diesel engine drives a massive electrical generator, and that generator drives the electric motors.
Your typical car hybrid has the ability for the gas motor to directly drive the wheels of the car, just like in a normal car. It also has the ability for the electric motor to drive the wheels of the car. And, they can both drive the wheels at the same time, or either of them can drive the wheels by themselves.
So that is the difference, whether the fossil fuel engine can directly drive the wheels of the vehicle.
The diesel locomotive solution is indeed a better approach, in that the fossil fuel engine can run at optimal efficiency at all times, with the vehicle speed regulated by the electric motor. It’s also a simpler mechanical situation, as you do not need to have two different power sources driving a single axel. You also don’t need a transmission. You do, however, need a larger electric motor than the typical hybrid has, and a much larger generator than normal. I still see it as a win.
I think only the Chevy Volt ever adopted this scheme in a road car. I have also wondered why this approach is not more common.
bjurasz explained it so perfectly I have little to add!
Legacy automakers are tradition bound and are stuck in a rut, as explained by Clayton Christensen in The Innovator’s Dilemma: When New Technologies Cause Great Firms to Fail. A funny case, BMW put grills on their EVs even when they are not needed, because that was their cars’ distinguishing feature. It’s hard to break with tradition.
BMW i3 hybrid does this as well - small ICE engine to charge the battery but no transmission or ICE drivetrain - and I agree it is a much more elegant solution for hybrid vehicles.
It wasn’t quite. The Volt’s engine could also power the wheels:
Chevrolet Volt - Wikipedia
" The Volt operates as a pure [battery electric vehicle]until its battery capacity drops to a predetermined threshold from full charge. From there, its [internal combustion engine] powers an electric [generator] to extend the vehicle’s range as needed. While running on gasoline at high speeds the engine may be mechanically linked (by a clutch) to the car’s gearbox, improving efficiency by 10% to 15%."
Locomotives use the series setup because it’s nigh on impossible to make a clutch that can take all that torque. Brush tried to do it with hydraulics - it was a disaster. Electric motors can give 200% rated torque at zero speed, for a short time.
The fact that gobs of other automakers - not even the non-tradition ones (and there are now hundreds of them) have adopted this scheme tells me that perhaps it’s not the best use for this platform. Maybe it is and of the thousands of designers in hundreds of auto design studios around the world nobody has thought of it yet? Unlikely.
That has nothing to do with tradition. That’s branding. McDonald’s still has arches, but they serve no purpose in holding up the building.
Not that many years ago, the gag making the rounds was a pic of an EV with a dead battery, with a gas engine driven generator recharging it.
Use a fluid drive. My dad used to work for American Standard’s fluid drive division in Dearborn. You regulate the torque transmitted by regulating the amount of fluid in the turbine. A fluid drive is a cousin of the fluid torque converter in a conventional automatic transmission.
Film at 11:00: how a fluid drive works. Note, at the 40 second mark, the film talks about where the company obtained the patents for their drives: from the former Industrial Products Division of American Standard. The pic they show is the building my dad worked in, as an application engineer.
The difference is that diesel electric locomotives don’t have batteries at all (except for starting). The BMW i3 mostly operates off its battery.
The issue is that trains change speed slowly. So a low RPM diesel engine is perfectly suited to generate electricity in this application because you can run at a constant speed for long periods of time. Cars change speed a lot, but that’s one of the things that make ICE’s inefficient. If your ICE is changing RPM all the time, you might as well just mate the power directly to the wheels.
Orinoco Mining, the US Steel mining subsidiary, used Diesel Electric trains to haul ore from Cerro Bolivar to Puerto Ordaz where it was loaded on ore carriers. Instead of just relying on breaks they used regenerative braking but having no batteries to store the electricity they used large air cooled coils to use up the juice which made a huge racket. The personnel manager commented that Puerto Ordaz had the highest birth rate in the country. The trains would arrive late at night making a terrific racket. Woken ip in the middle if the night, what else was there to do?
