mgs
[Top] [All Lists]

Re:basis for emissions standards?

To: mgs@Autox.Team.Net
Subject: Re:basis for emissions standards?
From: "Christopher G. Moog" <cgmoog@worldnet.att.net>
Date: Wed, 30 Jul 1997 06:45:17 -0400
Scott Gardner wrote
> How did it come to pass that emissions standards are expressed as 
> relative amounts like % CO or "parts-per-million" HC?

The OEM standards are in grams per mile which is fair for all engine
sizes.  However in order to make it easy to test vehicles at services
stations the periodic inspection and maintenance testing standards are
in ppm.  Testing in grams/mile requires a chassis dynamometer
(treadmill) to load the engine and a meter (called a constant volume
sampler) to measure total volume of exhaust.  This type of testing is
coming to many areas.  This test will be more difficult to pass (vehicle
must have an air tight exhaust system and run currectly under at
different speeds and loads) but is much fairer in that actual emissions
output will be measured.

> I would think 
> that this unfairly punishes small-displacement engines.

The current method does.

<Prev in Thread] Current Thread [Next in Thread>