Interesting idea, but, as you can see from the red highlight, the motor will shut off at stops.

I can see how that would be 'transparant' on electric motors, but how can it be so with an internal cumbustion engine? Wouldn't there be a delay when you hit the accelerator for the car to start back up?

 

I can see two things happening here. One, people will just keep their feet on the accelerator while at stop lights. Two, people calling the dealership saying "my car dies at every stop light, I want this fixed!"

If it ever makes it into a sports coupe, I think someone will find a way around it, ala CAGS or the like.

 

There is an economy button, it can be turned off. A/C does not run while it is stopped, heat does.

 

First thing I think of is reliability problems.

Starters only last so long...now you're asking it to make probably 10X as many starts....bound to be durability issues. Imagine the car shutting off at an intersection and not coming back on....

Second, I can see belt slippage issues. Going to be useful only on small displacement motors, anything big with high compression would burn up the belt.

Last, sort of blows a whole in the old wives tale that it takes less gas to idle than it does to start up.

 

does this mean that we're going back to a multi-belt arrangement? i'd imagine the alternater/starter would have to have a heavy duty toothed/notched belt to even have a chance at working.

 

That crossed my mind too....

 

The reason starters last only so long are because they are purposely designed as overstressed motors not intended for continuous running. If they didn't do it this way, a starter would have to be many times larger than they currently are. Going to 36/42 VDC cuts the amperage by 1/3, and therefore the same sized starter could be 3 times as powerful, or in this case, designed to properly handle the additional stress of all these starts.

That's pretty much always been just a wives' tale, especially since the era of fuel injection. I think the rule of thumb nowadays is that 15 seconds of idling wastes more fuel than restarting.

The Toyota and Honda hybrids already shut their engines off at stop signs. People will get used to it. No one buys a hybrid by accident; they know a little bit of what they are getting into before they sign the papers.

Another interesting starting technology (since we're on the topic) deals with the electrically operated valve systems everyone's trying to perfect. In theory it would be possible for the engine to know which cylinder in a stopped engine is near its power stroke, open the intake valve to let the fuel injector squirt, close the valve, then fire the spark plug to get the engine going. No electric starter required at all!

 

crazy! i had this exact idea in like '92. i was only 14 at the time too. i know, i know. everyone and their aunt dorthy has ideas.

 

What happens to the A/C while the engine is off?

 

This likely would not work. There are four things required to make an engine start: Air, Fuel, Spark, and COMPRESSION. Opening the intake valve would remove any residual compression in the engine.

Direct injection engines may be a different story. However, if the vehicle was sitting for long periods, the residual compression would bleed off over time.

Randy

 

Compression is required for efficient combustion. Some of the very first internal combustion engines worked at atmospheric presssure until the Otto cycle was discovered. Even with just, say, 1/3 of the cylinder filled with air at atmospheric pressure, there should still be enough expansion to push the piston down when it's ignited.

 

My camaro has that feature currently, except I think it's more of a stalling problem...

 

1. What we're talking about are "mild" hybrid cars - not true hybrids like the Prius. ("True" hybrids work a 300V+, mild hybrids work with 36 volts.) Toyota tried this in Japan with a Toyota Crown, but rejected the idea for the United States because the economy benefits were so limited.

2. While 36 volt electrical systems are the way things are going, the new GM system will still use 12 volt electrical components for accessories like power window motors. Unless they've worked out all the kinks, expect some major electrical problems down the road.

3. BMW has been running a 318i prototype with an integrated flywheel/alternator. Why you might ask?

The reason might surprise you. Forget the hybid crap, BMW is planning on a non-mechanical all electric valve train. All-electric valves will take huge amounts of juice, hence the alternator/flywheel.

4. Other than the 120V outlet on the new Silverado Hybrid, there is precious little functionality behind GM's new "innovation."