Diesel hybrids do make sense,
Diesel hybrids do make sense, and are being sold in other countries! The only reason I still drive around my >500,000 mile 1985 VW Golf Diesel is because they don't sell any diesel hybrids here yet. I just love it when I compare my MPG in my 1985 Golf Diesel to brand new hybrid owners and get better fuel mileage than they do!
As for polution, diesels actually do make less than gasoline cars if you don't have all the emissions stuff on them. Actually cars with dirtier exhausts tend to be the easiest to clean the exhaust on. Take the Mazda RX7 for an example. The HC and CO emissions without the catalytic converter were some of the worst in history. But all that bad exhaust made it easier for the catalytic converter to heat up and do its job, making the RX7 actually get some of the best tailpipe emissions of its time. Nowadays, gasoline engines are actually following diesels on both operation and emissions with modern direct injection and lean burn technology. With diesel hybrids getting into the hundreds of miles per gallon, like the VW XL1, I don't see how they are producing more CO2 than gasoline hybrids.