Air throttle and related systems

[pattypape]

Ralph,

Thanks for the info. I was unaware of the minimun
idle air pressure needed, I am hoping my idle problem was
not enough air pressure, when engaging the idle controlls.
It could also be the pressure reducing valve or the check valve.

This is a minor issue for me, not high on the list.
The electronic module seems to work fine at highway
cruise control speeds.


Bill 88 Fc


> Hello everyone:
>
> On a thread I started a few weeks ago on the air throttle and high
idles
> systems, it seemed unclear as to what happens and when on these
systems. I
> contacted Benny and received the "prints" on these systems and
have
> attempted to do a write up for everyone who is interested. Below
is the
> sequence of operation, as I interpret the prints.
>
> Air Throttle system/Cruise control/air break interaction
>
> Throttle control:
> 1. Coach air is supplied to the air throttle control valve (gas
peddle)
> which modulates the amount of air passed to the double check valve
to the
> throttle air cylinder.
>
> 2. There is an exhaust port on the air throttle vale that exhausts
excess
> air when less throttle is called for,
>
> 3. or the air break is used dumping all throttle air off the
throttle air
> cylinder.
>
> Cruise control:
>
> 1. Coach air supplied to the pressure reducing valve, from 120 psi
to 80 to
> 90 psi.
>
> 2. From the pressure regulating valve to the dual valve on or near
the
> Bendix cruise control module. The module controls the position of
the
> shuttle in the valve to call for more, or less air going to the TR-
3
> inversion valve.
>
> 3. From the TR-3 inversion valve to the double check valve,
>
> 4. and from the double check valve to the air throttle cylinder
>
> 5. There is an exhaust port on the TR-3 inversion valve to release
the air
> when the air break is pressed, exhausting the cruise control air
to
> atmosphere, kicking out the cruise control.
>
> 6. The Bendix memory holds the electronic sense position to return
the dual
> valve back to the preset position for resume.
>
> 7. Turning off the cruise control power switch or the Coach key
switch,
> resets the Bendix control module memory.
>
> Air break interaction:
> This is stated in the various actions in the above for the
Throttle control
> and the cruise control.
>
> Throttle air cylinder:
>
> 1. Pulls back on the attached cable to the throttle control on the
engine.
>
> Of course, all this is air controlled by the 60 psi air switch, so
the
> front air tank, rear air tank and the "wet" tank must have reached
60 psi min.
>
> Air systems:
>
> 1. The "wet" tank is supplied air from the coach compressor
through the
> governor and the air drier.
>
> 2. The front and rear "break" tanks are supplied by the "wet" tank
which
> there is a check valve between the "wet" tanks and the front and
rear
> "break" tanks.
>
> 3. All air systems in the Coach; air step/ride height air
bags/throttle
> control/up-down co-pilot step well cover/air ride seats/seat
slide/water
> winterizing blow out system, and so forth, are suppled from
the "wet" tank
> only.
>
> This is all separate from the "high idle" control system.
>
> The cruise control system on the FC's is similar to the PT's but
have a
> different control cylinder. That cylinder has electronic
positioning sensor
> which pulls the cable going to the bell crank on the cable/manual
throttle,
> and there are two solenoids that deal with the "clutch" part of
the old
> Bendix control. The "clutch" part interacts with the transmission
neutral
> switch to get the selectable "high idle" electronically.
>
>
> Safe travels,
>
> Ralph and Charolette Fullenwider
> Ralph's RV Solutions, Duncan, Oklahoma
> http://home.swbell.net/rlf47/index.htm
>