How does one go about engine power reduction without having emissions
violations when the accelerator is mechanical?
I'm a compression ignition sort, but in efi gassers, doesn't the
linkage go to a butterfly valve in the intake, and the ecu adjusts the
mixture per sensory inputs so as to comply with emissions
regulations? Doesn't leaning the mixture raise flame temperatures,
increasing NOx emissions?
With diesels, and a mechanically linked pump, you'd have to cut the
airflow... Drastically increasing particulate emissions due to
incomplete combustion (since diesels usually have excess air...).
Having an electronic input (even via actuator) to a mechanically
linked IP would throw in all sorts of reliability issues when compared
to an electronically governed one...
--
John W Reames
jwrea...@comcast.net
Home: +14106646986
Mobile: +14437915905
On Feb 16, 2010, at 13:12, Alex Chamberlain <apchamberl...@gmail.com>
wrote:
On Tue, Feb 16, 2010 at 3:51 AM, John Reames <jwrea...@comcast.net>
wrote:
The mechanical linkage is dead, gone and unable to be
resurrected;mandated
traction control has seen to it.
Ridiculous. The two have nothing to do with each other, though car
company accountants and marketeers would probably like you to think
otherwise. The electronic stability brain needs a couple of inputs
and a couple of outputs. Inputs include pitch/yaw sensors, wheel
speed, throttle position, and steering wheel position. Outputs can
include engine power reduction, selective braking, and/or selective
transfer of torque to a wheel or wheels. None of these require the
computer to have control over the throttle. Engine power reduction
can be accomplished by retarding timing, cutting spark to a cylinder
(in the case of a gas engine), or cutting fuel to a cylinder (in
diesels or in gassers). Selective transfer of torque among wheels can
be accomplished by application of brakes to one wheel forcing torque
to the other side on the same axle (given an open differential), or by
electromagnetic clutch packs. None of this prevents manual control of
the accelerator by the driver, including the ability to close the
throttle completely (or stomp on the brakes!) to slow the car
regardless of what the computers want to do.
Electronic throttle control is an artifact of cost-cutting. It's
cheaper to have one embedded computer controlling the entire car and
connected to everything via fiber optic bundles than to have discrete
electromechanical systems as in our beloved '80s Benzes.
I am hoping that we don't see some sort of overreaction which
brings parity
between the QC (and QC regulations) of automobile
parts/repairs andthose of
airplanes.
I'm much more interested in seeing some kind of mandatory licensing
based on competence for software engineers. Anyone who has worked in
high-tech knows that the majority of programmers are barely competent,
and that there are no accepted or enforced standards for testing their
work. And we trust our lives to these people every time we get in a
modern car.
Alex
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