---------------------
Forwarded message:
Subj: Re: rubber GTs
Date: 96-06-28 20:48:47 EDT
From: MGBCHRIS
To: jtilton@vt.edu
You probably asked the wrong guy, as this happens to be my line of work. A
rolling road dynamometer is essentially a large diameter drum, supported on
trunnion bearings, and connected to a drive of some sort. The drive is
controlled to simulate the inertia of the vehicle under test. The car is
"driven" on the dyno, while a variety of "roads" are simulated - i.e. hills,
etc., by varying the loads. During this process, the vehicle emissions are
monitored. Because the GT is heavier, more fuel is used to acheive a given
speed on the dyno. More fuel burn = higher emissions. In actuality, if all
other things were equal, a GT would put out lower emissions on the road,
because it got marginally better fuel mileage (due to better aerodynamics).
This fact was not taken into account during the EPA's early certifications.
Regards,
MGBChris@aol.com
|