Thread: WoW: supermini class diesel cars produce more NOx than a 40 tonne truck!

Originally Posted by DiscoMick

So wouldn't an auto gearbox keep a turbo diesel more in the ideal rev range and so produce less nox than a manual?

I don't believe so, typically North American based trucks have 18 speed gearboxes, Euros 12-14. Smaller trucks and Japanese models are usually fitted with 6-9 forward ratios. Automatic 'boxes (as opposed to ACM) have fewer ratios than their manual counterpart. More gears means that the vehicle can be driven in a narrower rev range.
Both automatic and ACM gearboxes are less efficient than a manual, in competent hands.

Electric cars of all kinds shift the pollution from 'running' to 'Infrasctructure/manufacturing'/generating/distribution, so the net co$t is not as positive as we'd like to think.
Or hope...

IMHO, it is time we went back to a much-maligned and better form of locomotion... Steam.

We see the occasional Stanley Steamer on vintage rallies, - obvious due to the steam/smoke trail. But decades ago we had a better one, the Doble which could be on the move in less than a minute from a stone cold start. Not only but also, they ran a (nearly?) closed-loop system, like nuclear subs do... "recycling" the steam back to water...

Bet you didn't know that VW was working on steam in the late '90s, and BMW may be still looking at using steam to reclaim waste heat in a vehicle...

And of course, the epitomy of steam efficiancy.... great power to weight ratio and controllability... the Besler steam driven AIRCRAFT. Besler at that time owned the DOBLE patents.

[ame]https://www.youtube.com/watch?v=nw6NFmcnW-8[/ame]

- But "Internal Combustion" engines prevailed...
Funny how a great technology can be displaced by a better-moneyed/managed one. The Doble brothers were their own worst enemies, constantly changing on the fly, no two cars were identical it was estimated.
And machining a part from a huge lump of metal, where everyone/anyone else was casting / machining... And Henry Ford specifying the tiniest details of how suppliers built their packing cases, so Ford could re-use the wood for things like running boards.
Call it what you like 'greed', 'smarts' or plain Good Management, Ford is still in business, Doble et al are barely memories.
Bit like BETAMAX and VHS video standards

A Doble-type engine in a Classic would be a huge improvement in speed, economy and maybe 'Reliability'.


Torque would be horrendous !

Originally Posted by roverrescue

I hear what you are saying about large diesels running at optimum loads. But the tests referred to in the article that is this thread were done on trucks trundling around London. I can't imagine a truck punting in traffic is operating at optimum loading. More so that other poke jiggery plus adblue is ensuring that heavy vehicles meet 0.08g/km ... I think that it is impressive that the truck companies have taken NOx emissions seriously but car companies have not....

The overall engine capacity may not be however the individual (and yes, Im being a little biased here in assuming that its been one of the latest and greatest trucks thats been quoted as beating the car in terms of emissions) cylinders will be.

by very clever (comparitively to older engines) management of boost pressure, how many cylinders to run, what order to fire them in, pre, post injection metering, sustainment injection, valve control to prevent pumping losses you can keep the emissions way down in part because of the number of cylinders, in part because the engine is going slower, because you have the overall engine capacity to do enough work to keep the engine running and produce the requried amount of power for the load AND you have enough rotating mass and block mass to be able to afford to only fire 1 or 2 cylinders in a seemingly random pattern every second or third turn of the crank and not shake the vehicle to pieces, then all the after care stuff that can be done at a lower comparitive overall cost per vehicle can clean up the little bit you miss.

I also think that the truck the test was done on was an auto, dont quote me I havent read the article, but if it was by tying the autos brain to the engine brain you can then do even more to ensure that the engine is given the best opportunity to run cleanly.

I personally dont think it was the "trucks" that lead the push for the cleaner engined stuff I think it was the concern about bus emissions but as busses are based off of trucks and there are more trucks than busses that the testing and development for whats now in busses came from the trucks that were used as a reseach base.

Originally Posted by Blknight.aus

The overall engine capacity may not be <snip> ...
I also think that the truck the test was done on was an auto, dont quote me I havent read the article, but if it was by tying the autos brain to the engine brain you can then do even more to ensure that the engine is given the best opportunity to run cleanly.
...

The London testing was not on specific vehicles but by roadside air sampling, data linked to the passing vehicle. So we can assume there were a variety of manual and auto trucks and buses

I stand to be corrected, but I'm under the impression that this roadside-reading is done in the US state of California... and is used to fine/charge the obviously bad polluters.

- Like a Speed camera but with a sense of smell....