A question about hybrid cars

[BlackSabb]

Hi everyone. I have a question regarding hybrid cars. The average hybrid car consists of an electric and petrol motor with a large and heavy battery pack. Usually, the petrol and electric motors run separately, with the electric motor running when light power is required and the petrol motor cutting in when extra power is needed. Of course, the battery requires external charging from a mains socket.

 

I was thinking why you couldn't have a hybrid with a petrol engine that runs continuosly, not connected to the transmission but only recharging the battery? My rationale for this is that you wouldn't need a large battery pack requiring about 6-8 hrs of runninig time. The battery pack on my proposed hybrid would only have enough power for 1hr or less. But it would only need that much as the petrol engine would continously recharge it. There would be an obvious major advantage in having a hybrid vehicle with only a small and light battery pack.

 

But there would be also major advantages for the petrol engine. Because it only recharges the battery and is not connected to the transmission, you could easily calibrate the petrol engine to a very limited rev range that is optimial for producing electrical power. You wouldn't need all this fancy direct injection, twin turbo charging, variable valve inlet and exhaust valve heads etc. You would only need a simple engine with a simple valve system that is designed for good efficiency at a narrow rev band-ideal for producing electrical power. perhaps too a very long stroke moter such as 110 mm which produces lots of torque simply.

 

Basically, I would have just enough batteries for a few minutes of power but constantly recharged through the running of the petrol engine.

 

What do you all think?

[swansont]

I was thinking why you couldn't have a hybrid with a petrol engine that runs continuosly, not connected to the transmission but only recharging the battery?

 

http://en.wikipedia.org/wiki/Hybrid_vehicle#Series-Hybrid

[BlackSabb]

http://en.wikipedia.org/wiki/Hybrid_vehicle#Series-Hybrid

 

 

 

I knew that diesel electric hybrids like I suggested have been common in trains. My question is why aren't these hybrids being built for cars?

[ewmon]

The Chevrolet Volt is a series hybrid.

 

I think many people want to understand what they're buying and driving. They want it to be simple, and series hybrids are the simplest. It's easy to understand that the batteries run the motor until they get low, then the gas engine kicks in and recharges the batteries.

 

Chevy doesn't advertise the Volt as a hybrid. They describe it as an "electric car" with a range-extending gas engine. That's why you hear them advertise it goes up to 40 miles before using any gas. This follows in the footsteps of their miserable EV-1 from a decade ago, and it gets a jump on the competition for all-electric cars.

[swansont]

I knew that diesel electric hybrids like I suggested have been common in trains. My question is why aren't these hybrids being built for cars?

 

Some shortcomings are discussed in the link.

[darkenlighten]

Awesome question! You should go to http://www.ecocarchallenge.org , it is a competition where 16 universities and colleges in North America design and build hybrid vehicles use the same base platform of a GM donated vehicle (it is now in the 3rd and final year). Advanced Vehicle Competitions have been going on for a while and they are a really good opportunity for students to learn how to build these vehicles, while also informing the public the new technology.

 

I am on the Ohio State Team ( http://ecocar.osu.edu/ ). We are actually building the type of vehicle you mentioned (where we are actually using E85 fuel instead of petroleum). And the thing is, as mentioned, it is being done. The Volt is a perfect example....and the ability to link the combustion engine to the wheels is actually advantageous as certain speeds, such as highway, where the efficiency of the combustion engine usually is better then the recharging process to use just the electric motor as a drive source.

 

The thing from here is letting people understand the technology and what can be done with it...I think GM is on the way to leading the industry towards the next steps to use less petroleum and hopefully none at all.