Air throttle and related systems

[Ralph L. Fullenwider]

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

[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
>

[Ralph L. Fullenwider]

Hi Bill:

The FC's have something the PT's don't, and that is 2 large solenoids to
the left of the Bendix control unit.

One day, I had the panel under the coach open, tracing a problem I was
having and nothing I did seemed to make any difference at all. Out of
frustration, more or less, I turned the bolts that held the solenoids to
the back of the panel and all of a sudden everything started working to
beat the band.

What I found was, rust had become an insulator and the solenoids were not
making a good ground so the system just would not work as advertised.
Interesting. Anyway, I pulled the bolts, wire brushed everything and re
installed with new stainless bolts, and what I thought was low voltage went
away. Just a thought.

I also cleaned up the valve, which was sticky and devised an inline gauge
to check the air pressures going through each point. Over kill I know, but
it sure took some of the do I or don't I stuff out of the equation. Then I
added a relay so the on/off switch pulled the coil of the relay and through
the contacts of the relay I went straight from the batteries to the power
input of the Bendix. That was a good mod.

Truth be known, Charolette had some "honey do's" for me and I was avoiding
them so I took the time to make the gauge set up for those checks,

Safe travels,

Ralph and Charolette Fullenwider
Ralph's RV Solutions, Duncan, Oklahoma
http://home.swbell.net/rlf47/index.htm

At 05:14 PM 11/27/2005 +0000, you wrote:


>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.
> >
>