[everything.imp]

I simply wanted to point out that the idea of my engine starting and stopping ever 5 - 10 miles doesn't sound very good. Ignition systems go out on cars and it's kind of scary for me to think about. I would feel much more secure with the engine being on constant after the original battery charge has been used.

My suggestion is to begin the charging process with an RPM that would generate enough electricity to pull the vehicle and slowly charge it at the same time. Then after it got to 35% charge slow the rpm down just enough that it would maintain or possibly lose a very small amount of charge due to what was being used. Then once it got down to say 25% or whatever begin the charging stage again. This may sound kind of dumb but I don't like the idea of my car starting and stopping over and over. I keep thinking of me sitting in a parking lot with my 99 pontiac firebird starting and stopping it every 5 minutes. Just doesn't seem good for the motor for some reason. It could very well be perfectly fine for the engine IDK but the point is the mentality of the consumer might possibly see this as a flaw in the design that may worry them about the durability of the vehicle.

 

[dilettante]

Since this is the way that typical hybrid engines work (the Prius and Civic Hybrid both turn their engines off every time you stop - in the city there could be less than a minute of driving with the engine on before it turns off again at the next stoplight), I assume that cycling the engine in this way won't be a problem.

 

[aliendroid]

Don't worry the're going to use the kind of starter that's designed for frequent start-stop just like other hybrids, but in the volt the start and stop will be less frequent in the city.

That reminds me of the glide and coast we do with the prius where the start stop cycle of the gas engine might be as little as 30 seconds yet the starters don't wear out.

 

[Texas]

Don't worry, I'm guessing there will be many different modes of operation. There might even be diver options. We have to let the software guys play with the car for a couple years. I’m hoping they will come up with something great. If not, the hacker community will.

 

[MikeKO]

Why would the start stop happen though? If you are driving around town with lots of starts / stops the battery only mode will last for quite some time (40 miles is a long time in city driving). If you are on the highway driving for a few hundred miles, the engine should come on and stay on.

 

[DonC]

Why would the start stop happen though? If you are driving around town with lots of starts / stops the battery only mode will last for quite some time (40 miles is a long time in city driving). If you are on the highway driving for a few hundred miles, the engine should come on and stay on.

I think the design does try to do this to some extent. The engine will run at one of three different set points depending on the driving conditions. But at some point you will end up with more energy than you need for moving the car forward. At that point the battery recharges. To prolong the battery life you don't want to charge it anywhere near completely, so after the battery charges to some set point you cut the engine and let the battery discharge.

On a level road -- and highways tend to be level -- you don't need much power to keep the car moving. Having the battery discharge is a fine idea which can get you better mpg. I don't see the problem. The start/stop process is in all GM soft hybrids and the technology seems to be very solid.

 

[Joshua Bretz]

I like the VOLT ICE recharge process and hope GM reads this too

The starter for the ICE might just be the generator, operating in reverse. You are right to worry about cycling - if the temperature of the exhaust is constantly changing, maybe this makes it fail prematurely. The electric portion of the drivetrain is going to last forever - I just hope the ICE can keep up.

However, turning the ICE on and off will yield a significant improvement in mileage while in charge-sustaining mode. You're either operating the motor at its peak efficiency point, or it's off. You can't get much better than that.

 

[king]

Don't worry, I'm guessing there will be many different modes of operation. There might even be diver options. We have to let the software guys play with the car for a couple years. I’m hoping they will come up with something great. If not, the hacker community will.

There is one point that should be noted. If you drive further than 40 miles but you arrive back home with a battery that isn't close to empty you burned gas to generate electricity that could have been purchased at lower cost.

It might be spiffy to always be on the GPS navigator even for familiar routes so the car would know how far you had yet to travel and whether you were going home or somewhere else [and you could mark, say, your friends' houses as places where you can get a charge]. This might not be a crowd pleaser because it's a small but finite chore to key your destination into the GPS when you don't need it, but it's only to your advantage to do it for long drives where the car will recharge itself. If you do that, and the drive is long enough, the car will promise to save gas by arriving at the house with 10% capacity left and by optimizing the recharge by using the fewest but biggest blocks of recharging possible.

-dk


-dk

 

[silvercorvette]

There is one point that should be noted. If you drive further than 40 miles but you arrive back home with a battery that isn't close to empty you burned gas to generate electricity that could have been purchased at lower cost.

It might be spiffy to always be on the GPS navigator even for familiar routes so the car would know how far you had yet to travel and whether you were going home or somewhere else [and you could mark, say, your friends' houses as places where you can get a charge]. This might not be a crowd pleaser because it's a small but finite chore to key your destination into the GPS when you don't need it, but it's only to your advantage to do it for long drives where the car will recharge itself. If you do that, and the drive is long enough, the car will promise to save gas by arriving at the house with 10% capacity left and by optimizing the recharge by using the fewest but biggest blocks of recharging possible.

-dk


-dk

Nope the wise thing is KISS. Why add in computers and GPS systems to do something a simple on off switch can do? This was mentioned in another thread

http://www.gm-volt.com/forum/showthread.php?t=1195


and it makes perfect sense to me. A computer will never make a better decision than the drive, computers and do many things better than people. ABS, anti skid are good examples but in this case a simple on off switch that the driver controls is cheaper and more effective than a computer.

 

[Aaron Bianco]

Generator/starter

I simply wanted to point out that the idea of my engine starting and stopping ever 5 - 10 miles doesn't sound very good. Ignition systems go out on cars and it's kind of scary for me to think about. I would feel much more secure with the engine being on constant after the original battery charge has been used.

I'm not trying to mock or ridicule, I just want to point out that the concerns you express are the type that become more significant as the cards get older. However, designs and materials are constantly improving, and a 60's model is always going to have more of a problem than a new car UNLESS there is a major design flaw. Whether it be transmissions, brakes, or other parts, they will always go out with use; however, the flip side is that there are significant saving to be realized during 'present operations' where the cost effectiveness (i.e. what you save later vs what you spend now) probably will not support your suggestion which raises the operating cost which is based on a 'chance' that within a normal vehicle lifespan of 8 years that one particular system will go out.

The starter for the ICE might just be the generator, operating in reverse.

One particular motor that can act in this capacity can be found at www.ChorusMotors.com. It can act as both a high speed motor and a low speed/high-torque motor.

I'm fascinated with it since it can only be found in Aerospace and I'm waiting for it to get picked up in other industries. It can do wonders for a Series Hybrid like the Volt. (See HERE for information on how it would affect Series Hybrids.)

 

[jrigg]

I will be driving my volt in one of three ways (this covers 99% of my usage).

1) Driving to and from work. I live 20.2 miles from work, so each work morning I will drive on surface streets for five minutes, freeway for 25 minutes, and then surface streets for another 5 minutes. Reverse on the way home.

2) Long trips from San Jose California, South to San Diego, and North to FLorence Oregon (we have vacation and rental properties there).

3) Errands and such, on work evenings and on the weekend. Variable distances and types of driving.

For 2) above, I would like to be able to tell the car's onboard computer that we will be travelling I-5, so that it can locate the points on the road where the grade is, and make sure that there is sufficient battery power to carry us through the uphill parts of our trips. That would require a more intelligent program of when to run the generator and when not. As an example, I would want the ICE to spark up southbound on I-5 so that we had a full charge at the base of the Grapevine, so that we could have as much torque as possible for the uphill climb.

So yeah, I hope that the programming includes a GPS/topography index for intelligent trip planning, or the capacity to manually tell it to "turn on the ICE so that we can travel on a fairly flat free for X miles, and then start up a mountain grade at that point.

Is this too much to ask do you think?

 

[DaV8or]

For 2) above, I would like to be able to tell the car's onboard computer that we will be travelling I-5, so that it can locate the points on the road where the grade is, and make sure that there is sufficient battery power to carry us through the uphill parts of our trips. That would require a more intelligent program of when to run the generator and when not. As an example, I would want the ICE to spark up southbound on I-5 so that we had a full charge at the base of the Grapevine, so that we could have as much torque as possible for the uphill climb.

So yeah, I hope that the programming includes a GPS/topography index for intelligent trip planning, or the capacity to manually tell it to "turn on the ICE so that we can travel on a fairly flat free for X miles, and then start up a mountain grade at that point.

Is this too much to ask do you think?

Interesting idea. Could be done. However I think their plan is to just make sure the ICE has enough power to get you and your family up the Grape Vine without need for the battery pack. The cool part is when you go down the other side you will be charging your battery pack. Think of it, you just set your cruise control for 65mph for maximum effect, the car maintains 65 down those steep grades without using any brakes and your EV range meter starts creeping up.

 

[Joshua Bretz]

To keep it simple, the GPS could just monitor alititude. The computer would have a table containing the highest and lowest points accessible by car nearby. It would not necessarily need to know topography road by road.

That way, if you live on the top of a hill, your charger could charge all the way to 100%, and discharge all the way to 0%, doubling your electric range with the same battery.