Steve Pardoe wrote:
Point of clarification:
The Prius does not wait for the application of the brake to begin the regeneration cycle. I've seen the display indicate regeneration at 50 miles per hour when the conditions are adequate. This is why steady driving is a good thing. If the electronics detects a request for 50 steady mph and there is a down slope of as little 2%, the controller may turn off the engine, turn on the motor, and may even begin regeneration. If the down slope is even more severe, but does not require braking to control the speed of the Prius, the electronics will still take advantage of the situation.
Your second point is offset somewhat by the continual running of a non-hybrid to support the ancillary requirements. The Prius air-conditioning is run off the traction battery, thus allowing complete shutoff of the engine at any complete stop. Given that some of our intersections require minutes of stopped cross traffic, that can be a major savings.
Probably the reason we don't have hybrid diesels for the U.S. is the high sulfur content of the petroleum we receive from our sources as opposed to the lower concentration in the supplies sent to Europe. There is a new requirement to lower that content at the refinery that should lead us to diesel hybrids as the best of both technologies.
In fact, I hope someone takes a close look at a serial hybrid (the Prius is a parallel hybrid in that both sources directly drive the wheels). A constant rotation diesel can be more efficient than a variable speed diesel. It would seem a diesel that charges a battery or capacitor that runs the motor would be the ultimate combination. And then, if we plug it in for the first twenty or forty miles of power requirements, we may have the best energy balance compromise.
Point of clarification:
The Prius does not wait for the application of the brake to begin the regeneration cycle. I've seen the display indicate regeneration at 50 miles per hour when the conditions are adequate. This is why steady driving is a good thing. If the electronics detects a request for 50 steady mph and there is a down slope of as little 2%, the controller may turn off the engine, turn on the motor, and may even begin regeneration. If the down slope is even more severe, but does not require braking to control the speed of the Prius, the electronics will still take advantage of the situation.
Your second point is offset somewhat by the continual running of a non-hybrid to support the ancillary requirements. The Prius air-conditioning is run off the traction battery, thus allowing complete shutoff of the engine at any complete stop. Given that some of our intersections require minutes of stopped cross traffic, that can be a major savings.
Probably the reason we don't have hybrid diesels for the U.S. is the high sulfur content of the petroleum we receive from our sources as opposed to the lower concentration in the supplies sent to Europe. There is a new requirement to lower that content at the refinery that should lead us to diesel hybrids as the best of both technologies.
In fact, I hope someone takes a close look at a serial hybrid (the Prius is a parallel hybrid in that both sources directly drive the wheels). A constant rotation diesel can be more efficient than a variable speed diesel. It would seem a diesel that charges a battery or capacitor that runs the motor would be the ultimate combination. And then, if we plug it in for the first twenty or forty miles of power requirements, we may have the best energy balance compromise.