I think large commercial vehicles and trucks/SUVs are a much better use of hybrid technology as the average familly car does not use anything like as much fuel.

James-

Don't take offense at being called a common man, I consider myself one too. The fact that there are more cars than large vehicles reinforces James' point even more. The expense of fitting millions of cars with control systems and batteries will not be small. But how about fitting the UPS fleet? I think the right technology might have a very quick payback for them, whereas a soccer mom might have to drive the lifetime of the car to see the cost savings. Sure there are other considerations, but trying to consider everything hurts my head, so I just keep score by looking at cost savings.

Ultimately it would be nice to have every vehicle fitted, but it makes sense to develop the technology where it is most suitable.

JRod.

I think Lithium batteries are the solution to bipolar batteries.

It has a clutch and an automatic transmission? What's up with that?

(a) Some 80% of all freight in Europe is transported by trucks, because of technical incompatibilities between the national railway systems. Therefore, improving truck fuel consumption has a much bigger impact here than in the US, both economically and in terms of environmental parameters.

(b) Hybrids are generally thought to bring benefits in urban stop-and-go traffic. This is because a car engine is typically operated in (low) partial load where internal friction sharply cut fuel efficiency.

Heavy duty truck engines spend most of their life near their torque limit. Adding a hybrid electric motor saves fuel by recuperating energy on descents and time (= money) due to more rapid ascents. This is why the power rating of the batteries matters more than their capacity.

Of course, like cars, hybrid trucks also save fuel in traffic jams. Another benefit is reduced emissions during transients, because the electric drive can reduce torque demand dynamics on the diesel engine.

(c) Li-Ion batteries will make sense for cars. In an HDV, battery weight and acceleration performance are far less critical than battery cost and life expectancy - return on investment is the top priority, environmental benefits a distant second. I just hope Volvo is prepared to accept the recycling burden of its lead-acid design.

(d) Some automatic transmissions also feature a clutch. It lets them bypass the wasteful torque converter except in first gear and during gear changes. Fuel economy then becomes comparable to a manual transmission. Moreover, recuperative braking reduces the load on the retarder, which typically uses the transmission fluid. In combination, due to lower average temperatures, that fluid will last longer.

Great conversation, all. The clutch can be used for a number of functions with the I-SAM. IF there is another clutch downstream the I-SAM motor can be spun to high rpm then an "inertial start" can occur by closing the upstream clutch. This allows the I-SAM to start the engine without sizing the motor to produce huge starting torque. Also, if the I-SAM motor is large enough, it can propel the truck at low loads without running the diesel. Cheers.