Hi,
Quote:
Originally Posted by Double-Trinity
I completely agree that the diesel hybrid would be the greatest pick for MPG. However, the main explanation I have heard for why a diesel hybrid might not work out is that it would be too expensive once you include the cost of the clean diesel emissions equipment, and the hybrid drivetrain. It would be similar to paying a "hybrid" premium twice. Also, the hybrid assist would not lead to as much of an improvement for a diesel as a gasoline engine hybrid -- one of the major benefits of the hybrid is that it makes up for poor low-end torque found on efficient gasoline engines. Diesel engines already excel in low end torque though, so there would not be as much room for improvement from adding the motors.
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So how much expense is too much??? Just enough to require an either or decision? From what I can tell, the diesel premium is rapidly disappearing. The cost of stronger journals and engine blocks for a diesel is relatively small. As for the injectors, some of the common rail, electric valved systems (a high pressure version of the low-pressure fuel injectors) should solve that problem, especially if enhanced with a spark, pre-heater (aka., ink jet printer technology.)
My thinking is the ultimate answer is a Sterling, external combustion ICE feeding an electric drive train. External combustion means complete combustion with minimal, post combustion scrubbers or converters. It also means ultimate 'flex fuel' since if it burn it churns. In fact it would be two Sterling engines of 1 cylinder and 2 cylinder size. This would let them generate 0%, 33%, 66% and 100% of their maximum rating. Finally, Sterling engines have excellent thermodynamic efficiency so you get out about as much energy as can be extracted from a heat engine. Their only drawback is a fixed speed and three cylinders gives four power levels.
So take a Volt (a PowerPoint version will do for now) and replace whatever ICE they put in with a three-cylinder, variable cylinder operating Sterling and modify the control laws to run the Sterling when the battery drops in proportional to the energy drop rate. The EV part otherwise works as before. As for the Sterling, it quietly sits in the rear and efficiently makes electrons move.
Bob Wilson