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From: paul@ubvax.UUCP (Paul Fries)
Newsgroups: net.auto.tech
Subject: Re: trivia question
Message-ID: <370@ubvax.UUCP>
Date: Tue, 26-Nov-85 19:01:37 EST
Article-I.D.: ubvax.370
Posted: Tue Nov 26 19:01:37 1985
Date-Received: Fri, 29-Nov-85 21:52:03 EST
References: <600@drutx.UUCP> <3177@hplabsb.UUCP> <635@bonnie.UUCP>
Reply-To: paul@ubvax.UUCP (Paul Fries)
Organization: Ungermann-Bass, Inc., Santa Clara, Ca.
Lines: 34

In article <635@bonnie.UUCP> wjh@bonnie.UUCP (Bill Hery) writes:
>> > Why do cars have clutches?
>> > 
>> > Because, the engine has to keep running while the car starts from a stop.
>> 
>> Correct!  Gasoline and Diesel engines have zero starting torque.
>
>Not a correct answer to the original question, which asked for the
>reason NOT INCLUDING SHIFTING GEARS.  This solution seems to refer
>to the need to shift into neutral for starting.  Can the original
>poster respond with the correct answer (assuming that this isn't it)

I must disagree with this analysis.  Consider a car with ONLY ONE GEAR
THAT IS ALWAYS ENGAGED.  Even though you cannot shift this beast, you
still would like a clutch for starting the car from standing still.

If this is not a practical enough example, consider a beast that was
seen on the drag racing circuit a few years ago.  It was a fuel dragster
that was equiped with a LENCO two-speed planetary transmission (I might
be wrong about the name "LENCO", but that is not really important).

This transmission was similar to the planetary arrangement found in
an automatic transmission, except that it was manually (as opposed to
hydraulically) operated.  The point is that there was no neutral; the
gears were always engaged, and shifting the thing did not involve the
clutch.  The vehicle was still equiped with a clutch so that it could
sit at the starting line with the engine running.

What it boils down to is that the clutch is really only necessary to
get the car moving from standing still because internal combustion
engines (including diesels) have zero starting torque.  All the other
uses of a clutch can be handled by other means, but there must be
something to disconnect the engine from the wheels so you can stop
the vehicle with the engine running.