Re: [SystemSafety] The VW Saga

From: Mike Ellims < >
Date: Mon, 12 Oct 2015 12:10:20 +0100


> I assume that VW are expert at making diesel engines. So are other
companies. I expect that all engine manufacturers
> routinely examine competitors' engines extremely carefully and learn from
what they find.
> So it must be difficult to achieve far better performance than your
competitors unless you have patent protection for some breakthrough.

Companies share engines quite widely e.g. Peugeot specializes in small engines which as (or at least where) used by Ford in Europe. Manufactures share "platforms" as well, for example I think that the current Ford Fiesta is basically a Fiat Punto in drag, it's also done widely within companies e.g. the Audi TT is basically a VW Golf. They more or less all have a pretty good knolage about what each other is doing; but not perfect knowledge.

The problem with diesel and to a lesser extent petrol engines is that what you get out of the tailpipe is a strong function of the combustion temperature. In a nutshell high combustion temperatures give you, low hydrocarbon & particulate emissions but good fuel economy and high NOx output. To lower the NOx output you have to lower the combustions temperature which means that other emissions and fuel economy get worse. The peak points for all everything are of course all in different places... making for an interesting optimization problem. Then there is the issue that the load and speed are continuously changing.

It's of course much more complex than that and also depends on injection pressure, injection timing, number of injections per firing (3/firing is common), cylinder temperature, fuel mixing (swirl) which in turn depends on the inlet ports and shape of the piston and head etc. etc. etc.

Various techniques are also used to tailor the combustion environment e.g. ERG feeds CO2 back into the cylinder to drop peak temperature, adding ethanol to petrol makes and extra oxygen atom available. Demand management is also used, e.g. when loads are high the air condition pump and the alternator are turned off for short periods. When all else fails external equipment can be added e.g. catalectic converts and particulate trap. All of which adds complexity and cost.

>From a technology perspective the basic problem is that it gets harder and
harder to make the next set of improvements required by the regulators expect that the regulators make it easier than it could be to pass the tests, in that they have specific drive cycles that engines can be optimized for.

> It seems that one (at least) of VW's engines was very much worse in
emissions than the regulations allowed.
> None of their competitors have been caught yet with the same problem.

All the information at the moment seems to point to the fact that many (most?) of the vehicles tested on the road do worse than the regulations allow e.g. four times the NOx allowed which isn't surprising given that the engine only has to meet the regulation drive cycles. However VW were caught with their pants down in they added a "defeat device" i.e. a hack to specifically defeat the test procedure in the USA.

> So, do all the competitors have some patented technology that gives them a
huge advantage?

No single major advantage, lots of small advantages put together and optimized in company specific ways to produce a package.

-----Original Message-----
From: systemsafety-bounces_at_xxxxxx [mailto:systemsafety-bounces_at_xxxxxx Martyn Thomas
Sent: 12 October 2015 10:07
To: systemsafety_at_xxxxxx Subject: Re: [SystemSafety] The VW Saga

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

I assume that VW are expert at making diesel engines. So are other companies. I expect that all engine manufacturers routinely examine comtetitors' engines extremely carefully and learn from what they find. So it must be difficult to achieve far better performance than your competitors unless you have patent protection for some breakthrough.

It seems that one (at least) of VW's engines was very much worse in emissions than the regulations allowed.

None of their competitors have been caught yet with the same problem.

So, do all the competitors have some patented technology that gives them a huge advantage?

Martyn

-----BEGIN PGP SIGNATURE-----

Version: GnuPG/MacGPG2 v2
Comment: GPGTools - http://gpgtools.org
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/

iQEcBAEBCgAGBQJWG3grAAoJEAev1z3Tv8QL/mwH/A2SadEhcKKf2aXofEFVQNcc JtLQ8URs85LP8I5g/1y/H5UMBtlzh5BZRczfsNQUQ7urnF7ckccMgTfWg3guB4DC 3tIsBj5DSM5r019DGP0xbX1iMimTxNDrU8g9uqUT27XhgqyIiOmEhupJQnAxYKHj xEDnw1R9zRzliQmQfyMOB8vRWze8xfmnCxLByTbfybbQ0T35lgUIngvAWq1n1VIJ 2RaU3TyFhizD6tyiYY5OpLnoYE5dZSiYouRgzJQiASosj2wUkYphLLi/FAPg68Vr D0UlTEKQqzkkrJpS3Ui5vnH8/yfQQoPfQKNQnx0vt6wS3YUUQIKswlMLy8FMZLw= =suWC
-----END PGP SIGNATURE-----



The System Safety Mailing List
systemsafety_at_xxxxxx
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

_______________________________________________
The System Safety Mailing List
systemsafety_at_xxxxxx
Received on Mon Oct 12 2015 - 13:10:41 CEST

This archive was generated by hypermail 2.3.0 : Thu Apr 25 2019 - 03:17:07 CEST