2009 VW Jetta 2.0 Diesel (with particulate filter): EPA 30-41 mpg, HP 140, ULEV certified in California.

2006 VW Jetta 1.9 Diesel (no filter): EPA 30-37 mpg, HP 103, not certified in California.

There has been an INCREASE in efficiency with the filter-equipped engine for these two vehicles with identical bodies and weight. And the ULEV rating (better than some gasoline cars) was obtained without urea injection. Honda has developed a similar engine that should be available soon.

-Refining methods used in the US produce higher ratio of gasoline:diesel than those used in Europe, so diesel production will always lag in the US and as one result, diesel vehicles will necessarily remain a smaller portion of the US fleet.

-Without having switched to low-sulfur diesel, we would be unable to use the latest high-efficiency, high-output diesel engine technology (which among other characteristics uses very high fuel pressures unavailable to the older fuel). See, e.g., Audi at LeMans. This ain’t your cousin’s diesel Eff Two-Fiddy.

-US federal tax on diesel is higher than for gasoline, $0.244/gal vs. $0.184/gal.

-PM2.5 and PM10 standards will continue to be tightened to reflect the increased understanding of their negative health effects. Regulation is being extended to heavy construction equipment and stationary sources, such as diesel generators.

http://current.com/ items/ 88965612_don_t_buy_that_new_prius_test_drive_a_used_car_instead

This shows tha value of (a) design for recycling, and (b) keeping the design as simple and minimalistic as possible and (c) replacing vehicles less often. The Prius has all those extra components (regenerative braking, electric drive mechanism, batteries, control electronics) which all have to be manufactured, serviced, carried around in the vehicle and disposed of / recycled and which, on a freeway journey, contribute nothing.

The Toyota Yaris diesel has 32% better mpg than the identical car with a petrol engine.

However, the CO2 emissions are only 16% better per mile (because burning a litre of diesel emits about 2,630 grams of CO2 compared to 2,300 grams for a litre of petrol).

The diesel engine also emits 0.021 g/km (34 mg/mile) of particulate matter emission. The global warming disadvantage of this soot counteracts the CO2 advantage.

With 32% better mpg and 34 mg/mile of PM, this diesel engine is slightly on the better side of Jacobson’s illustration of a 30% better mileage and 40 mg/mile PM car. Figure 3b in his report shows the net impact of the soot disadvantage vs the CO2 advantage for this illustration – very marginal, but a very slight worsening of global warming. The little bit better PM emission of the Toyota Yaris’s 34 mg/mile probably pushes it very marginally onto a very slight improvement side (but to be securely on the improvement side diesel engines will have to achieve only 20 or 10 mg/mile).

Conclusion: the warming impact of a Yaris car is pretty much identical with a diesel engine or a petrol engine. The headline CO2 saving is cancelled by the soot impact. The big tax incentives offered in European countries to persuade people to buy diesel engines are thus misplaced, but at least aren’t making things worse.

[NB The Toyota Yaris comparison looks to be fairly typical of small European cars. A Peugeout 207 can have either a diesel engine or a petrol engine: the diesel gets 40% better mpg and 20% better CO2 emissions; its PM emission is 29 mg/mile.]

The entire European strategy for cars and global warming is based around a switch to diesel. By saying California is right, you are saying the European Union is wrong.

There’s a big tax incentive in the UK, for example, to choose the Yaris diesel over the Yaris petrol – lower annual road tax and lower taxes at the filling station. I would save money with the diesel, despite paying £1,000 extra for the car.

Half Europe’s new cars are diesel due to this strategy and incentives.

This is perhaps a bigger story than Joe and Jacobson realize – it’s saying an entire continent is on the wrong track.

http://www.volkswagen.co.uk/ assets/ common/ pdf/ brochures/ polo-brochure.pdf

All engines (petrol and diesel) comply with the toughest emission standards currently in force (EURO 4). For diesel engines this is:

CO 0.50
HC+NOx 0.30
NOx 0.25
PM 0.025

This last figure is the carbon particles and will pass anywhere in the world except the latest California LEV II standard of 0.01

http://www.dieselnet.com/standards/us/ld_ca.php

What is the Prius like on recycling? If you read the VW Blue Motion ads there is a whole section on how every part is marked with the material type so it can be fully recycled and rare metals recovered from components such as the catalytic converter:

http://www.volkswagen.co.uk/bluemotion/

The reality we’re experiencing supports this conclusion. With a whole bunch of fancy gadgets (SCR, ECR, particulate trap) and additional maintenance (ammonia/urea supply), modern diesel struggles to comply with California’s minimum emission standards, while gasoline cars go far beyond the minimum and achieve ULEV/SULEV status.

Also, the “short-term” life of soot is in the atmosphere. Once the soot settles on polar ice, it doesn’t just disappear. It continues to convert sunlight to heat.