Subaru Hybrid

Does anyone know off-hand what percentage they own?

And Suzuki itself is owned partially by GM. Not sure if that's GM or GM Canada. And why is it GM Canada that owns Subaru rather than the main corporation?

Yousuf Khan

Now see this is how I figured hybrids would be done in the first place. It just seemed like what better way to do AWD, not to mention being able to do away with complicated transmission and drive-train. Why didn't Subaru take this route?

I think they should have spent the money on this rather than developing the Tribeca. With gas prices as they are, the last thing I want is to buy a vehicle that sucks up even more gas. Seems to me a hybrid Forester with in-wheel electric motors could really stir up the market, especially with the already strong reviews of that vehicle.

last i heard 20%.

According to

Interesting, Suzuki owns 2.69%

There would be more unsprung weight with this kind of vehicle, which would affect handling. You would have to find additional space inside the wheel wells for these motors, which would affect interior cabin and/or cargo space; at the very least you wouldn't be able to put on those huge extra-wide bling-bling tires. You'd have to put four electric motors in there rather than just one central one. The motors being right in the wheel would have to be designed to absorb quite a bit of shock since they are unsprung. You'd have to route wires to all four wheel wells, and make sure the wires are protected against the elements somehow.

Need I go on?

Yousuf Khan

And there's more. The Toyota system cleverly feeds the gasoline engine power and the electric motor power into a differential, which is able to add the power from the two sources and create an output to the wheels. This is how they get a stepless automatic transmission. If the electric motors were in the wheels, all the power would have to be electric, so the total electric power would be the maximum horsepower of the car. The Toyota system is able to get by with a smaller electric motor.

I haven't thought this through completely, but it also seems to me that you would never be able to drive the car with the gasoline motor, and at the same time put power back into the battery. This could be an issue if you have run the battery down by, say, driving up a long mountain grade, and are now cruising around town with a low battery.

All of those would be engineering challenges for certain. But there may be many positives which could balance out the negatives. Lower CG, better F/R weight distribution, more interior space options/safer cabin design, lower/more aerodynamic profile, etc. Those motors may not be as heavy/large as you think. Probably only need about 4-5 HP per wheel(think, electric lawnmower motor size). Electic motors can tolerate large excurions above the 'continuous duty' rating for a short time and it only takes 10-12 HP to move a vehicle down the highway at a constant 55 MPH(so acceleration is gonna require those big 'excursions' certainly). Plus there may be a way to use chain or belt drive for the wheels and 'spring' the actual motors. Tricky, and doubtful the finished product would be identical in 'road feel' as a nice vehicle is today, an Element feels different than a Jaguar, feels different than an STI, feels different than a Jeep, etc.- but, there never seems to be an end to selling 'odd' vehicles to the public!(especially if you bribe them to try it with a tax break!) The main advantage I see hybrids having is , they use the current(no pun intended!) infrastructure for 'normal' cars. Same wheels, tires, lubricants, and fuel.

Carl

YKhan wrote:

how about getting rid of the battery all together? do it like the diesel locomotives do. you optimize the gas/diesel engine for one optimal RPM (it doesn't have to be one RPM, but you can get better efficiency if the engine is designed for a narrow range). it just sits and runs at this rpm and generates electricity to go to the motors. no need for lossy transmissions or anything like that. just some wires going to the wheels. i guess you could still have a battery in there that stores extra power for a boost durning acceleration or something, or to catch some of the energy during braking. as another poster said, you wouldn't need terribly big motors for this. typically a diesel locomotive is only rated at about 2000HP or so.

granted there will be issues about larger amounts of unsprung weight, i'm sure that's more easily solvable than all the complicated engineering that goes into creating vicous couplers and limited slip differentials and all the stuff we already have today.

What do you mean they get a "stepless" automatic transmission? Isn't that what they call a CVT? I know that the Honda system has a CVT in it, so it's likely that the Toyota does too.

The Toyota electric motor has a maximum power of 13HP (10kW), it's just there to add a bit of extra spunk to the gasoline engine when the need arises.

If the batteries are low, then the gasoline engine will never be shutdown they will keep turning until they've filled up the batteries to a sufficient level again. Sort of like a fawcett refilling a bucket back up that got dumped out.

Yousuf Khan

And let's not forget that nobody actually drives at 55 mph, most will probably be cruising at 65 to 70 mph, which would mean that you would already be excursing over the continuous duty rating just to cruise.

Once you start moving the motors inboard of the suspension then the need to have separate electric motors per wheel drop away. You might as well have one motor for the whole system, or perhaps one motor per axle.

Well, precisely why they are called hybrids.

Yousuf Khan

Actually, locomotives are now getting batteries.

In the past, a locomotive used the motors as generators while braking in a process called "dynamic braking", sending the generated power to large resistor banks in the top of the body. This power was then wasted as heat by the resistor banks, and actually required energy to run cooling fans.

Hybrid locomotives will now store the energy generated during braking, and use it later to provide forward motion.

Gets a flash presentation

Click on "Transportation Rail"

Barry

Those sound like problems indeed, and I believe clever engineers can solve them, over time, as they have solved many tough problems thus far.

Tom

Seeing as I am one of those clever engineers, let's see if I can solve it on the spot.

(...Thinks for a while, writing things on a quad pad...)

Got it. Here is one solution:

Unsprung weight affecting handling assumes a spring/damper (AKA shock absorber) system with a fixed weight on the end.

Build your heavy motor/wheel assembly with an additional counterweight in it equal to the weight of the other components. move this weight up and down with a linear actuator so that whenever the wheel hits a bump and moves up, a sensor senses the movement and tells the actuator to drive the counterweight down. The tire/road forces and the forces acting upon the spring/damper (and thus the frame) would be the same as if the unsprung weight was zero.

If the engineer was *really* clever, he would devise a way for the counterweight to be a battery that can take the G forces, thus avoiding any increase in total vehicle weight.

That's just my first shot at a solution, of course. If I was doing this for pay I would do some experiments and simulations, and I would take a long look at replacing that spring/damper with an actuator, giving me an active suspension.