The basic Sterling engine is really quite simple consisting of an expansion cylinder and a compression cylinder. The main difficulty is that it requires very high temperature alloys in the cylinder to withstand the high operating temperature required for efficient operation. Here's someone who's developing practical Sterling engines including using one in a prototype hybrid car.

I think UN did some serious trails use and sterling engine in the 3. world. But the cost was to high.

 

Cars with small engines and turbochargers are more efficient at higher revs. A turbocharger increases efficiency so at low revs before it has kicked in, it is just as bad as a normal car.

The problem is the small turbo engines have very narrow power bands. When normal drivers need to accelerate at normal rates, the tranny is downshifting several gears to crank the revs up all the time and that is NOT efficient.

This month's Motor Trend has a comparison test where they noted that the car with the small turbo engine missed it's EPA mileage rating by the widest amount (like actual was 5 mpg below rated).

 

Many modern engines have systems that cut off fuel to cylinders not in use. They also have variable valve timing and variable ignition timing to "detune" the engine. The modern trend is very small 4 cylinder engines which are turbocharged to make very light weight and still have high peak power. This is a disaster as their actual gas mileage is far below their EPA ratings since the driver has to "rev up" to get any power at all. That means the engine is running in a very inefficient mode a lot of the time. But there are still lots of cars with good V6 and V8 engines that give good power and economy.

That certainly wasn't my experience. I bought an '89 Ford Probe with a 2.2L turbo and 85.000 miles on it. If I went gentle and kept my foot out of the turbo, I could get 43mpg out of it. If I drove it "normal" to get up to speed quickly I got about 35mpg. I was quite impressed by that turbo. Going up the approach to Monument Pass (~7500ft AGL) doing 75mpg I romped it and it very smartly walked right up to 110mph. It also handled the 12,000ft passes with no problem.

 

That certainly wasn't my experience. I bought an '89 Ford Probe with a 2.2L turbo and 85.000 miles on it. If I went gentle and kept my foot out of the turbo, I could get 43mpg out of it. If I drove it "normal" to get up to speed quickly I got about 35mpg. I was quite impressed by that turbo. Going up the approach to Monument Pass (~7500ft AGL) doing 75mpg I romped it and it very smartly walked right up to 110mph. It also handled the 12,000ft passes with no problem.

I was just forced to drive a brand new KIA Sorento (little CUV) while my car was in the shop. Tiny I-4, turbo, 190 HP. Absolutely gutless engine. Gassed up and drove it home 150 miles late at night down I-5 (no traffic) with the cruise control set at 70 mph, never varied. Only "load" was 170 pounds of me and 95 pounds of wife. Gassed up to check the mileage when I got back and it was a dismal 22 mpg. RIDICULOUS.

I remember on the "half mile" climb coming up the grade just outside of town that stupid engine had to downshift twice to maintain 70 mph. By the time we crested this meager hill, the engine was revving almost 6000 sounding like it was ready to blow. My wife was looking at me like I was a madman and I held my foot up and said:

"Ain't me, it's the cruise control. That's how hard the engine has to work to do 70."

 

Consumer Reports tested the Prius at 55MPG highway. Considering a all-gas auto that gets 40MPG highway, that's a 37.5% better rating for the Prius. I know of no other technology that can improve fuel efficiency that much.

 

Consumer Reports tested the Prius at 55MPG highway. Considering a all-gas auto that gets 40MPG highway, that's a 37.5% better rating for the Prius. I know of no other technology that can improve fuel efficiency that much.

I recently took a trip in the prius from Houston to Hattiesburg MS, 460 mi. On the way there I drove conservatively, avg speed 65 mph, drafting trucks when convenient, and I got 59 mpg. On the way back I was in a rush, avg speed 85 mph, and I got 41 mpg. This is far better than you could get from a comparable sized all-gas car, but I think it could be better yet. I think that getting the engine involved in traction is a mistake.

 

Well, remember that hybrid technology is new, and improving. If you look at real MPG numbers for hybrids, they've gotten better over the years. To get the maximum economy from hybrids, it shoud be operated in the way it was designed for.

Involving the engine in traction isn't an effeciency killer. The way the design is supposed to work is the engine runs at it's maximum efficiency and electric motors make up the power budget when accelerating or hill climbing. It just isn't designed to be maximially efficient at sustanied power driving. No technology can be everything to everone.

 

Well, remember that hybrid technology is new, and improving.

I agree, and I think the way we improve technology is by identifying shortcomings in the current edition and suggesting solutions for the next revision, which is essentially what I'm doing.

If you look at real MPG numbers for hybrids, they've gotten better over the years. .

As A matter of trivia, I believe the most economic mass produced hybrid to date was the 2002 Honda insight (the ugly duckling) at 72 mpg.

To get the maximum economy from hybrids, it shoud be operated in the way it was designed for.

I disagree to some extent. The cars should be designed for the way people operate them, not the other way around. Of course there is a limit involved.

Involving the engine in traction isn't an effeciency killer. The way the design is supposed to work is the engine runs at it's maximum efficiency and electric motors make up the power budget when accelerating or hill climbing. It just isn't designed to be maximially efficient at sustanied power driving. No technology can be everything to everone.

I agree, that is how it is SUPPOSED to work, but it doesn't always.
This is why I propose an all electric drive. It is maximally efficient across the full range of operation.

 

I think that getting the engine involved in traction is a mistake.

Maybe at some point the hybrid EV manufacturers could take a lesson from trains--use only electric motors to drive the wheels. The gasoline engine, when running, would only run at constant RPM, the RPM of maximum efficiency. The electricity generated would be more than needed than to drive the car on the level, and the excess would charge the battery. If the battery became fully charged while driving, the gasoline engine would shut off until the battery became depleted by a predetermined amount. This cycle might repeat several times on a long trip.

Subaru currently has cars featuring a continuously variable transmission (CVT) which attempts to keep the engine running at the most efficient RPM range.

 

Maybe at some point the hybrid EV manufacturers could take a lesson from trains--use only electric motors to drive the wheels. The gasoline engine, when running, would only run at constant RPM, the RPM of maximum efficiency. The electricity generated would be more than needed than to drive the car on the level, and the excess would charge the battery. If the battery became fully charged while driving, the gasoline engine would shut off until the battery became depleted by a predetermined amount. This cycle might repeat several times on a long trip.

Subaru currently has cars featuring a continuously variable transmission (CVT) which attempts to keep the engine running at the most efficient RPM range.

The train sounds like exactly what I propose, except for the batteries. I suppose several tons of batteries aren't as much of a consideration for a train as for a car. The prius has a CVT as well, and my friend's Saturn SUV has one too. I believe they are pretty common in a lot of vehicles these days.

 

As A matter of trivia, I believe the most economic mass produced hybrid to date was the 2002 Honda insight (the ugly duckling) at 72 mpg.

What I was refering to is the increase for the same model over the years. Real MPG numbers for the Prius have increased by about 10MPG since its introduction, though size and weight have stayed pretty much the same.

I disagree to some extent. The cars should be designed for the way people operate them, not the other way around. Of course there is a limit involved.

You're getting into a chicken/egg thing. Cars are designed for the way people operate them, but all design involves compromise. Hybrids are designed to be maximally efficient for the conditions most people will operate them under. For those who want to operate outside the norm, then hybrid isn't for them.

I agree, that is how it is SUPPOSED to work, but it doesn't always. This is why I propose an all electric drive. It is maximally efficient across the full range of operation.

I imaigine there will be many different technologies in the future, to include all electric drives and hybrid drives. To me, it's an exciting, wide open technology market and more interesting things are yet to emerge.

(Changed the above comment after re-reading the post I was responding to.)

 

I guess I wasn't completely clear. Trains don't have tons of batteries. The part I was suggesting to adopt from trains is to not have the fossil fueled engine (diesel in the case of trains) directly drive the wheels. In diesel electric trains the diesel engine drives a generator and the wheels are driven by electric traction motors.

What are you suggesting? Not having batteries at all and have the gasoline engine drive a generator, and electric motors only driving the wheels, just like the diesel electric train?

 

I guess I wasn't completely clear. Trains don't have tons of batteries. The part I was suggesting to adopt from trains is to not have the fossil fueled engine (diesel in the case of trains) directly drive the wheels. In diesel electric trains the diesel engine drives a generator and the wheels are driven by electric traction motors.

What are you suggesting? Not having batteries at all and have the gasoline engine drive a generator, and electric motors only driving the wheels, just like the diesel electric train?

no, you were clear. I don't blame you for not reading my original post, I know it was rather lengthy. I am suggesting exactly the train setup, but a capacitor bank instead of a battery bank.

 

no, you were clear. I don't blame you for not reading my original post, I know it was rather lengthy. I am suggesting exactly the train setup, but a capacitor bank instead of a battery bank.

Then it's not exactly the train setup, except with capacitors instead of batteries, because trains don't batteries. The diesels drive generators that drive the motors. No energy storage device involved.

While considering the way trains do things is worthwhile, it should be kept in mind that the reasons that lead to trains using this approach are not applicable to the operating conditions of cars. The problem with a train is the need to provide a LOT of torque at essentially zero RPM for an extended period of time, since it takes a long time to get a train moving. Direct coupling an engine to the drive wheels is not an attractive option. If they could direct couple the engines to the wheels once up to speed, they would because they would bypass the inefficiencies of the generators and the motors. Some early diesel-electric trains did this, but the extra cost didn't justify the savings. Now, with fuel prices much higher and environmental regulations much stiffer (and with major regulations being proposed for locomotives) this may get reconsidered at some point.

 

no, you were clear. I don't blame you for not reading my original post, I know it was rather lengthy. I am suggesting exactly the train setup, but a capacitor bank instead of a battery bank.

I would like such a setup also, but as I pointed in post #13, it's not practical with existing supercapacitors. Not only that. but even the best batteries of today can't give you the mileage you can get from a conventional gasoline powered car. Too bad. It would be nice.

There's another problem that would arise if we did have a suitable battery, and every car on the road were pure electric. The existing grid wouldn't be able to handle the load that would occur when all those cars were getting their energy from the grid.

 

If they could direct couple the engines to the wheels once up to speed, they would because they would bypass the inefficiencies of the generators and the motors. Some early diesel-electric trains did this, but the extra cost didn't justify the savings. Now, with fuel prices much higher and environmental regulations much stiffer (and with major regulations being proposed for locomotives) this may get reconsidered at some point.

Also, the fluid drive system that allows cars to smoothly apply motor torque wouldn't be practical on a train scale. There are simply more degrees of freedom that allows efficient methods to be applied to cars that don't translate to other conveyances.

 

Then it's not exactly the train setup, except with capacitors instead of batteries, because trains don't batteries. The diesels drive generators that drive the motors. No energy storage device involved.

Whether trains have batteries or not, I don't know. I was just going off what the electrician said.

 

seems like a good idea. I'd alter a few things. make the drive motor a universal motor. that way eliminates the need for inverters. engine>generator>*, rectifier> controller> cap bank> drive motor. I would put in some sort of relay system so that when the engine is driving the vehicle it will send AC to the motor possibly making more efficient. This would also eliminate the issue of no power in cap bank or a failure of the cap bank.
for the accessories I'd just use some sort of dc-dc converter with a good range, then tap this off of some of the caps. Not sure what cap values would be, but say 6V per I'd take 4 of those and put a tap at like 24V then input to inverter. this would output steady 12V then can use normal car electrical parts.

I had thought at one point a car with possibly no engine. would be similar to prius, or your idea, but instead of engine and generator. wrap the car with wire. as it drives the earths magnetic field would generate power in the coil charging some storage system then running electric motor.

I saw something earlier today about an 85 MPG car called Honda fit. it appears it won't be available in the US though until later. apparently special design body that some reason for us their going to use same system but in a compact sedan/crossover.

 

I had thought at one point a car with possibly no engine. would be similar to prius, or your idea, but instead of engine and generator. wrap the car with wire. as it drives the earths magnetic field would generate power in the coil charging some storage system then running electric motor.

Note the mechanism here. "As it drives...." This means that you have a motor expending energy to make this wire-wrapped generator car work. The only thing you are absolutely guaranteed is that you will expend more energy than you will produce.

 

The Eaton Corp is already supplying UPS...maybe FedEx...and Coca Cola with hybrid vehicle drive trains....
When the vehicle stops ....the energy that is usually burned up (lost) in the brakes goes to drive a hydraulic pump which charges an accumulator....the hydraulic pressure and flow from the accumulator is used to start the vehicle and get it up to speed then the engine takes over...
For vehicles that start and stop a lot....like UPS for example it saves about a billion dollars a year in fuel, I think....
Its not a new concept...but Eaton has made it work and has sold a bunch of these drive trains ......
Im sure you can find something about it on the web...