Quote:
Originally Posted by Arragonis
As I understand it Hybrids at the moment fall into 2 types.
- The Prius type with batteries storing regen / engine power which is used to drive or assist as required.
- The Insight type where the batteries store regen power which is used to assist but not to drive the car exclusively.
The Diesel Hybrids I've seen suggest they are going down the Prius route, which I assume is much easier to retro-fit to an existing vehicle, albeit with a loss in luggage space because of the battery pack and of course weight.
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This is fairly accurate. I would emphasize the Honda Insight, Integrated Motor Assist (IMA) approach allows the high-torque capability of an electric motor to make a small displacement engine perform like one the next size up during acceleration. Several years ago Honda had a nice web page showing how the IMA fills in the torque needed at low rpm.
In the case of diesels, they pretty much have all of the low-end torque needed. This is my speculation about a diesel-hybrid version which today are mostly announcements of future products. The hybrid version should provide more engine OFF time and electric vehicle (EV) operation. This can avoid fuel burns at low power settings when the internal friction becomes a significant part of the fuel budget. It will also capture a significant part of the energy lost in braking.
Quote:
Originally Posted by Arragonis
Are there any Diesel-Electric hybrids, now or planned or built in a garage ? I'm thinking like the old Diesel-Electric locomotives idea of a Diesel engine powering a generator which in turn powers electric motors - so the Diesel engine can stay at the optimum speed for load vs fuel use. It also means top torque from zero engine speed.
What would that mean in terms of the engine size, or rather the power required, and weight ? Does it make a smaller hybrid possible ?
A second point if I may, ironic this one. Part of the marketing push on the Mk2 Insight here in the UK is that it is an alternative to a Diesel, because you don't need the heavy duty gear needed for a 'fuel of the gods' engine - clutch etc. And now they are putting Diesels in Hybrids. Hmmm.
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"Planned or built" . . . well there was this Top Gear approach which I believe involved a diesel powered generator strapped to their . . . 'machine.' I forget the episode but think of a box wrapped in aluminum sheeting with a dome on the roof for one of the presenters. I believe they used 'cartoon physics' in the design.
It is really hard to speculate on what a diesel-hybrid will actually be when delivered as there are subtle design aspects, 'fork-in-the-road' where either path works. To some extent these decision also come from a corporate culture about what drives their preferences.
As for commenting about marketing, I try not to curse before after-work, 'happy hour.' . . . Marketing, where really awful engineers are sent. The incompetent ones become managers. <grins>
Bob Wilson