Wheel Motors to Drive Dutch Buses

The innovation is the combination of the wheel motor and control system, but the company doesn't want to give away details.

I'll check about the particulate filter / engine--I'm assuming the bus will be equipped to meet European standards, so may need some changes for the U.S.  That's a good point about the revs.  The GPS system for turning off the engine completely in congested areas should also help.

The motors are in the rear wheels, so it should be able to limp home if one fails. I imagine you could just correct by steering. But I'll check on that, too.

Response from Arend Heinen:
I do not know what the U.S. emission stands are, but we can fit any type of energy supplier in the back of our vehicle. From biodiesel engine to hydrogen stack.

If we build a bus for the U.S. market it will meet U.S. standards. At this moment we build them according to European standards.

Anyway, we have 50% of the emissions of a standard diesel bus and save at least 70 tons of co2 per year in standard operation.


We can use the same particle filter as normal engines have. We have the extra benefit that the engine will run at a specific rev number to ensure the most efficient burning of the diesel.

Yes we can drive on with one motor easily. The top speed can be reached but the acceleration is less.

If one follows the news he can read about Hybrid Bus Technology.  Therefore predict the next production inovation.  Example: A Hybrid Bus Company in San Diego who retrofits used buses and recycles them into city transit buses.
danahyatt.mail@gmail.com

Good question. I doubt that the reduction in parts of two U-Joints per drive wheel will make much cost difference between a wheel motor and an inboard more conventional electric motor in a better protected location. Additionally, when applied to lighter vehicles such as passenger cars, wheel motors increase the sprung weight making for a harsh ride. Inboard motors would decrease the sprung weight and make for a better ride. (Kind of like the reason to use light-weight alloy wheels instead of heavy steel wheels.) I am in favor of using 4-wheel electric drive and eliminating the steering system by using control of revolution speed and direction at each wheel under direction of the on-board computer.

Thank-You Arend Heinen ,

Yes , with that many cells even though the cells take the power slower than ultra capacitors a little power in each one will work just fine .
Looks like you have a winner here . I would do the same thing , if I was working on the project .
I would still want to take a bus and put some capacitors in it with the batteries just to know for sure that it didn't make any difference . That is the Engineer thinking in me .
They will also make the batteries last a lot longer .

Mr Heinen, could you provide more detailed explanation and maybe some basic calculations to substantiate the fact that the batteries used in your bus can "absorb all the energy that is coming from the wheels in normal breaking situations."

The matter is five days ago I created a topic at one Russian forum for discussing the news on your leading-edge technology, and the discussion is still goin on. Today I was nonplussed by a forum member's critical post as rendered by me in English:

The bus is normally braking by recuperating energy, say from 72 km/hr to zero, i.e. its initial speed is some 20 m/s. Its total weight (including the bus itself and its passengers) is at least 20 metric tons, maybe more.
Hence we can calculate the energy to be absorbed (and later on to be spent on acceleration) as follows:
1/2 * 20,000 * (20 * 20) = 4,000,000 J = 4 MJ
Let's assume that the braking takes about 8 seconds (emergency braking should take some 2.5 seconds, but that surely involves some mechanical braking system). Hence the power the batteries being absorbed for 8 seconds amounts to some 500 kW (the more the better; a little less is admissible too, but only a little: we should always keep in mind that lower power absorbtion rates means longer braking).
What does this 500 kW mean for 30 batteries? It means 17 kW per battery. If we divide that amount by the rated voltage we get the charging current: some 1300 A. You can beleive me, that's a heck of a current!
If we can halve the deceleration (acceleration) rate, the charging (discharging) current will amount to 650 A. Believe me, even for the best batteries with storage capacity of 130 Ah the current of 650 A is just too much. It's possible to meet even such harsh requirements but only at the cost of much lower efficiency, below 50%.
Sure if acceleration and deceleration is done very very smoothly, even 100 kW might be enough, meaning some 250 ... 260 A per battery, which is roughly sufficient to fully charge the battery in 30 minutes. Such batteries do exist but their efficiency is rather low. I tell you again, nowadays' technology can provide high efficiency (up to some 70 percent) only if the charging (discharging) current is below the current necessary to fully charge the battery in 30 minutes.


Your reply will be appreciated.

Unsprung weight worries?  This is a bus, not a sports car.  I don't think you would notice any changes in handling ability or increased braking distances.  The limiting factor is the original design; a rather large, heavy, high center of gravity vehicle.