It depends on what you are doing with it. Any conversion of energy has losses. If I get 100W of power from the engine... convert it to electricity... put it in the battery... convert it back to eletricity... I can't get 100W back.

When you can make a smaller engine do what a larger one can because of the torque advantage, and you have to move the vehicle and the weight of the engine, and the larger engine is less effient because it isn't necessary for it to be that large except during acceleration, you can make a gain in effiency because that can outweigh the losses, which the hybrid does. But most of that doesn't apply to an A/C. The engine is already moving the car... the A/C is just an add on.

Thats all I'm trying to say... and apparently not doing a very good job of it. In any case...I'm going to let things drop at this point. We've had a pretty lively debate but I don't think we are going to change each others minds.

 

It was actually a loaded question. Almost all trains now, except for the occasional dinosaur steam engine, run on electricity. Whether they get it from an onboard generator or from overhead catenary wires, the traction motors are electric. You are correct in your statement that getting a train moving requires huge amounts of torque but there is more to it than that. Using the diesel to actually move the train would require gearing and varying the diesel engine speed - kinda unpractical. Using an electric traction motor you get the low-end torque but they can also be run at higher speeds (and it takes very little torque to KEEP a train moving). IIRC, electric motors have a flat HP curve and a torque curve that peaks at zero rpm and goes down from there. The diesel motor (coupled to a generator or alternator now) can be governed to it's most efficient rpm.

Being one that also likes a lively debate, I couldn't help but point out the error in that statement. EE, ME, CE.....engineers are all alike.

 

An excerpt from a review of the MMH:

"It was more than 90 degrees outside, but the Mercury Mariner I was driving decided that it really didn’t need the help of its 2.3-liter, four-cylinder gasoline engine.

Instead, the car’s nickel-metal hybrid batteries powered all the accessories, including the air conditioner and power windows, while I waited. In comfort."

 

That article is incorrect, as most test-drivers are newspaper reporters, and not experienced mechanics or hybrid owners.

The FEH and MMH can only run Air Conditioning from the gas engine. The battery does not have nearly enough capacity for A/C.

The reporter was confused since the FAN keeps blowing air during EV ( battery ) driving, but the air-conditioner is really off. But all this is invisible to the driver, until the air gradually warms up over time. ( 2-3 minutes before it becomes really noticeable ).

-John

 

I agree, that article is certainly a mistake.

If that reporter had been sitting in 110 degree weather they would have realized very quickly that the A/C does NOT blow cold air when the ICE is off.

~John

 

I saw this car at the SAE show in Detroit in 1973. You could balance a nickel on the engine while it was running and rev it up without the nickle moving or falling off. Totally agree that a gas turbine based hybrid would be the way to go. Probably won't happen for the same reason Chrysler isn't making gas turbines today.

JG

 

You are absolutely right.

I was only offering it to the group as one of those humorous "where do rumors like this start".

 

I've thought about that a bit... I don't think a hybrid is the best description of what you'd build with a gas turbine. You'd probably never drive the wheels with the turbine.... you'd drive a generator and electrically drive the vehicle. The problem is shutting the darn thing off. Part of our advantage is turning off the engine at intersections. A gas turbine would have to continue to run at high speed (you can't change their RPM very fast either) at an intersection as it takes forever to spin up. But you could use a big battery to store that energy....

Its an interesting design problem... pretty cool really. If it gets any more play in this thread though we should start another