Why can Prius ICE be shut down but regular engine cannot?

The technology has been wide spread in gas-electric hybrids but has now moved over to conventional vehicles to improve mileage and lower emissions by shutting off the engine when it's not being used. Instead, the car's systems, such as stereo, heater or air conditioner, gauges, lights and windshield wipers run directly from the battery, while the engine is off.

Why Our Favorite Vehicles Are Conking Out at Red Lights

 

Start/Stop technology has many forms and is becoming more popular.

Start/Stop: Making the Most of Just Hanging Around - Road & Track

 

It is worth noting that Motor/Generator 1 in the Prius acts as a starter, a generator, and (in Heretical mode) as a propulsion motor, so it is not true the Prius has no starter, just not a dedicated starter.

 

For an example of what you might be thinking of, look at the Malibu BAS system from I think a generation ago. GM tried to sell it for $1000 - $2000 more than their conventional model, but since it only increased fuel economy 5-10% it was a failure.

 

Yep. Those mild-hybrids were a total failure in sales (and their batteries apparently were crap too).

Now they sell 2nd generation BAS mild hybrids and don't even use the word hybrid in the model's name (e.g. Malibu Eco, Lacrosee eAssist). Now they're #3 in hybrids sales and being even Honda. See August 2013 Dashboard - HybridCars.com.

BAS Hybrid - Wikipedia, the free encyclopedia has some more info, but I don't know how accurate all of it is.

 

Good overview, but it misses a very important point: how fast the car may travel and still keep the ICE spin at zero.

 

The Panamera may win that at 103 MPH. (when deaccelerating)

But basically the article is about start/stop which is all about not idling.

 

AUTOMOTIVE TECHNICAL ARTICLES, starting w/the 1st hybrid article might be worth a skim, by the OP.

 

Decent article but there are some weird typos and possibly copy and paste errors in there.

I thought the article made an error about 2nd gen BAS being 115 volts, as I thought they stuck w/the 36 volts employed by 1st gen BAS mild hybrids. I guess I was wrong. http://www.evsafetytraining.org/~/media/Electric Vehicle/Chevrolet Malibu Eco ERG.pdf mentions 130 volts.

In my search, I also stumbled across some interesting tidbits at http://www.gmfleet.com/content/dam/gmfleet/global/master/nscwebsite/en/Home/Shared_Resources/PDFs/GMC1-12-01151-229-eAssist.pdf. Of particular note is that the ICE will NOT shutdown if it's any other gear other than drive (e.g. Park).

 

The ICE in a regular car doesn't need to be on to power everything. There are people who remove the alternator to reduce engine load (they generally use a deep cycle battery and charge at home). There are also others who manually turn off their engines while coasting and/or stopped. The Prius just makes it easier for the average person to do (and you have some electric assist). Plus regular starters probably wouldn't last quite as long.

 

I think the best explanation of the Prius operation is in the graphics in this link. you can play with the sliders and see how they affect road speed and engine speed and even reverse.
Toyota Prius - Power Split Device

John (Britprius)