Quote:
Originally Posted by fan
From a current thread ('Characteristics of the 1.4l engine'), the gas engine of Volt will deliver 100hp. For this type of car this may be decent as a maximum power output (even when battery is depleted).
I don't think it is wise to assume that a driver of a Volt would like to behave accordingly to Volt's 'will' - When the battery gets to 30% must go home slowly and recharge the battery.
The car may know that is close to home, but the driver may get an urgent call to get fast somewhere 100 miles away. This car should allow him to get decent there.
So, I guess that when the battery is depleted and the car is under stress (driver in a hurry), it should be possible to rev the engine to get those 100 hp or more to power the emotors directly through the generator. Normally the engine would run at optimum rpm deliver less power to the generator.
Also, the 'power of the car' should be limited to this maximum power the gas engine can deliver with or without charged battery. It wouldn't be safe to have the car behave differently depending on the state of the battery. Like making a pass and especting to get 6s to 60mpg, but since the battery is down, this time you get only 12s and best wishes.
And since it's an electric car, people would be glad to get 9s to 60m and 100 mph speed, so no need to conceive complicated and dangerous scenarios for various power outputs of the car.
It may be possible to fit the car with a more powerfull engine for better performance (like the 140 hp version the Curze is getting), but that would mean that either the engine will assist more the batteries, or the batteries would have to deliver more power (more charge-discharge; decreased lifetime). Allowing for more power output means allowing for more agresive driving, which lowers the mpg and the mpg figure is the make it or break it for the car.
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This is how rumors get started.
The VOLT will not have proximity detection to one's destination. People change their mind. Remember, there will be future VOLT drivers whose TVs will stop working in February.
Most people on this site are seriously overestimating the average power output of their engines during driving. Thanks to the need for transmissions - when accelerating you are very rarely using the max output of the engine, even with the pedal floored. Look at hp curves, they are not flat. Remember, the VOLT's motor can supply a rated hp continuously into the generator. Road conditions, speed, traction do not affect that generator. There is no shifting. It can run all day long at max output - without varying one bit.
Will the generator have a few operating bands? Possibly. We'll see. It could run at max efficiency and cycle more, or it could try to match the power band with the current demands, and run more constantly. That could be more efficient as less power would go into the battery, and thus less would come out when the motor was off, but that depends on what the bands do to the watts / gallon generated by the genset. These are the types of things that will be figured out during validation. NVH concerns could play a part too. It could sacrifice max efficiency to be quiet unless max efficiency correlates with max power and is necessary.
Bottom line. You drive how you want. When you hit a certain percentage of charge, the generator comes on. It runs until a certain higher state of charge is reached. Then it shuts off. If you just happen to pull into the driveway and you could have made it, but instead the motor ran for the last 2 minutes, who really cares. The overriding concern is consistency of experience for the driver. Thats why 120mph and 6 sec 0-60s went by the wayside.
Maybe future e-flex vehicles will use DoD on the genset to allow for more spirited driving. A low power gen mode for normal driving, and a high power mode for sustained high speed operation. Who knows. That's not in the design goals for the VOLT.