Why not OFFER the Diesel in the US????? And what's with using 4 speeds with the smaller, less powerful engines, but a 6 speed with the most powerful ones??

Bud -

the engine cannot meet US emissions. I suggest you direct your fire at those who decided that CO2 is not a pollutant that EPA and CARB are permitted to set limits on. Not being responsible for fuel economy means they don't much care if their regulations reduce it. To its credit, CARB is trying to limit CO2 but the auto industry immediately sued them because that has hitherto been the preserve of the federal Dept. of Transport.

Elsewhere, e.g. in Europe and Japan, a single agency is responsible for both fuel economy and noxious emissions.

Wrt the gear number: smaller engine, cheaper car, lower comfort requirement, lower top speed => cheap transmission. Bigger engine, more expensive car, higher comfort requirement, higher top speed => more gears.

It's not clear which transmission the inline 4 diesel will be offered with in Europe. Most competitors rely on 5 or 6 speed manuals and offer an AT as an upgrade option. Note that the 2.0L turbodiesel produces as much torque as the 3.5L naturally aspirated engine, probably at much lower RPM. Maximum power is lower, but how often do you actually operate an engine at full throttle on any passenger car?

Bud -

and that is why combining a diesel with an electric motor would give you more torque than your wheels would know what to do with (unless you have mechanical or electrric AWD or, a RWD commercial vehicle with heavy paylod).

EPA & CARB would get drawn and quartered in the courts if they stepped back from ever-more stringent emissions regs, unless Congress decide to redefine their charter.

One liter or less. Two cylinder opposed. Two cycle, air cooled.

I assume he's baiting people. Can't be serious. It would be super loud, and the air cooling would make it even louder and tolerances couldn't be as close. Lastly, it would have to have a blower, they won't even run with a turbo until the exhaust reaches a high enough temp. Lots of weight, etc. That's how EMD and detroits used to be set up. Four strokes have taken over in everything except the ultra massive ship engines.

2 cycle diesels of 10,000 kw or more can get close to 50% efficiency. They are mostly ship engines and large emergency backups, but may be modified to run on other fuels(natural gas)/fuel mixes(biodiesel-ethanol-hydrogen).

In all fairness, the two-cycle GM Detroit Diesels really weren't a bad engine. When introduced in 1937 they were able to run at least 350,000 miles before maybe requiring top-end overhaul, and Greyhound Bus Line wouldn't retire a bus until it had 850,000 miles on it. At this time, you couldn't get more than 35,000 miles out of a gasoline engine before it required a valve job or worse.

Also, the GM buses from the late '40s and early '50s when setup with the 4-71 engine could easily get 10 m.p.g.
Today, a modern bus with similar passenger capacity is hard pressed to get over 1.6 m.p.g., and the hybrid units struggle to achieve 2 m.p.g.

Dave, a 4-71 means 4 cylinders at 71 cubes apiece. 284 inches of diesel wouldn't even come close to powering a bus, and none of them were turbo then. They did have 6-71's back then, but still.......(They eventually had v-8 and v-12-71s, and with turbos feeding the roots blowers, they were quite powerful). As far as blowing away today's fuel consumption by a factor of nearly 10, come on man!

Before saying that the GM 4-71 could never power a bus, and doubting the fuel economy potential over modern buses, you may want to look at this:

http://www.billvons.com/bus/buspage40.htm

http://www.omot.org/roster/GMOldLookList/tdh3714.html

http://www.autogallery.org.ru/zis154.htm

(The Russian ZIS 154 had a Russian license-built 4-71 set up with a unique, but inefficient, electric drive system which DID NOT get anywhere near 10 m.p.g.; however, it could still manage around 5.88 mpg, over twice the economy of the best hybrid buses built today!)

The GM 4-71 and 6-71 are still built today in Russia at the plant we gave them, under Lend-Lease, in 1947.
(They are known today as the YAZ-204 and YAZ-206 series)

http://auto126.kharkov.ua/engines.php

City buses only need to go about 40 m.p.h.; of course, highway units will go faster, at least 60 m.p.h.
Uh, couldn't find any information on ones able to get more than 5.9 m.p.g., and supposedly without airconditioning?

http://www.billvons.com/bus/buspage40.htm

"All PD 33 and 37 series models with the letter "A" were air-conditioned" (early 1940s!) and "very economical buses with 10+ MPG common with the 4 cylinder diesel engines. Top speed was almost 60 MPH at 2150 RPMs, but with the "4 banger" engine they died on any hills they climbed."

60 m.p.h.? I remember that not too many years ago in my state, the police would write you a ticket if they clocked you 5 m.p.h. over the 55 limit, so speed really isn't an issue, either.

(Sigh!) Pollution controls have absolutely killed ANY chance of getting decent fuel economy in modern road diesels, as Our Wise Environmentalists at the E.P.A. have mandated that NOX levels be reduced, which can only be done by making the engines run hotter (retarding the injection timing, where you basically make the engine work against itself). I don't know what to do about that one, but that's what happens when you have government mandarins telling engineers how to design diesel engines.

Dave -

fyi, modern diesels use multiple injections to shape combustion noise and NOx emissions. In part load, they use cooled external EGR to reduce the rate of heat release.

In general, NO is only produced in significant amounts above 2000 deg K. The innocuous NO is converted to the smog-forming NO2 partly within the engine but mostly under the influence of sunlight in the atmosphere. That is why the NO mass measured during vehicle certification tests is used to compute an equivalent NO2 mass.

Reducing engine-out NOx emissions (= tailpipe NOx in diesels w/o NOx aftertreatment) requries a redution in the peak temperatures that occur in the flame front. Late injection achieves this by igniting more of the fuel when the piston is already well past TDC, thereby limiting peak chamber pressure. The downside is reduced thermodynamic efficiency (i.e. higher fuel consumption), which is only partly compensated by the higher exhaust enthalpy available to the turbocharger.

I recall the 2 stroke GM diesel buses well from their extensive use in my home town of San Diego in the 1950's. They were horribly noisy and dirty, using a 2 speed auto trans, that was full torque converter in first(thus peak revs from zero mph), then clunked into a lockup top gear at about 25mph. I often thought they were made dirty and noisy to discourage the use of public transport, and hence more car sales for GM(who had apparently already bought up, and torn down, the trolley system).The ones in San Diego used open windows for air conditioning...they did seem reliable tho, and I can't recall ever being stranded on one.

What forced busses and cars to get more power was overcrowding of the roads, poor road design, and a massive increase in the number of 18 wheelers on he road.

It didnt matter if you were slow in 1960. In 1980 it mattered a fair bit as often many merge lanes were 1.3rd the length old lanes were and the roads had far more people and heavy trucks on em...

Now... its insane. Roads that became dnagerously crowded in 1980 have yet to be expanded.. routes that were overcrowded in the 80s still have no laternate routes... And yet more trucks on the road...

Where I live everyone commutes with the 18 wheelers and other BIG trucks every day. You only have to drive by one small car vs multiple semis accident to never drive one ever again.