1-4
62--11052
1.5
COMPRESSOR UNLOADERS
The compressor is equipped with unloaders for capacity
control. This consists of a self-contained, cylinder head
hot gas bypass arrangement. (See Figure 1-5)
The compressor unloader system can be controlled with
either a pressure actuated valve or an electrically
actuated (solenoid) valve.
1.5.1 Electric-Controlled Unloaders
The capacity controlled cylinder is easily identified by an
electric solenoid which extends from the side of the
cylinder head. When the solenoid energizes, the
cylinder unloads allowing discharge gas to circulate as
shown in Figure 1-6. The unloaded cylinder operates
with little or no pressure differential, consuming very
little power. A de-energized solenoid reloads the
cylinder as shown in Figure 1-7.
1. Discharge Check
Valve
2. Discharge Manifold
3. Solenoid Valve
4. Piston Bypass
Control Valve
5. Cylinder Head
6. Suction Manifold
6
1
2
3
4
5
Figure 1-5. Compressor Unloader
a. Major Working Parts
1. Solenoid and valve system
2. Spring loaded piston type bypass control valve
3. Spring loaded discharge check valve
b. Unloaded Operation
Pressure from the discharge manifold (Figure 1-6, item
15) passes through the strainer (9) and bleed orifice (8)
to the back of the piston bypass valve (7). Unless bled
away, this pressure would tend to close the piston (6)
against the piston spring (5) pressure.
With the solenoid valve (1)
energized
the solenoid valve
stem (2) will
open
the gas bypass port (3).
Refrigerant pressure will be bled to the suction manifold
(10) through the opened gas bypass port . A reduction in
pressure on the piston bypass valve will take place
because the rate of bleed through the gas bypass port is
greater than the rate of bleed through the
bleed orifice
(8)
.
When the pressure behind the piston has been reduced
sufficiently, the valve spring will force the piston bypass
valve
back
,
opening
the gas bypass from the discharge
manifold to the suction manifold.
Discharge pressure in the discharge manifold will close
the discharge piston check valve assembly (14)
isolating the compressor discharge manifold from the
individual cylinder bank manifold.
The
unloaded
cylinder bank will continue to operate
fully
unloaded
until the solenoid valve control device is
de-energized
and the gas bypass port is closed.
1. Solenoid Valve
2. Valve Stem
3. Gas Bypass Port
4. Spring Guide
5. Spring
6. Piston
7. Piston Bypass Valve
8. Bleed Orifice
9. Strainer
10. Suction Cavity
11. Cylinder Discharge
Valve
12. Valve Plate
13. Cylinder Suction
Valve
14. Discharge Piston
Check Valve
Assembly
15. Discharge Manifold
11
1
2
3
4
5
6
7
8
9
10
15
12
13
14
Figure 1-6. Electric--Operated Unloader--
Unloaded Operation
c. Loaded Operation
Discharge pressure bleeds from the discharge manifold
(Figure 1-7, item 15) through the strainer (9) and bleed
orifice (8) to the solenoid valve stem (2) chamber and
the back of the piston bypass valve (7).
With the solenoid valve (1)
de-energized
the solenoid
valve stem (2) will
close
the gas bypass port (3).
Refrigerant pressure will overcome the bypass valve
spring (5) tension and force the piston (6)
forward
closing
the gas bypass from the discharge manifold to
the suction manifold (10).
Cylinder discharge pressure will force open the
discharge piston check valve assembly (14).
Refrigerant gas will pass into the compressor discharge
manifold.
Summary of Contents for LE MIRAGE XLII BUS SHELLS
Page 1: ...COACH MANUFACTURER MAINTENANCE MANUAL LE MIRAGE XLII BUS SHELLS PA1564 1ST EDITION...
Page 12: ...Section 00 GENERAL INFORMATION 10 PA1564 FIGURE 13 METRIC US STANDARD CONVERSION TABLE 00005...
Page 13: ...Section 00 GENERAL INFORMATION PA1564 11 FIGURE 14 CONVERSION CHART 00006...
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Page 63: ...SECTION 01 ENGINE PA1564 33 FIGURE 13 POWER PLANT CRADLE INSTALLATION 01140...
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Page 229: ...FAULT CODE MANUAL Created on 00 04 25 15 30 1 FAULT CODE MANUAL B7L B7TL B12...
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Page 379: ...Section 12 BRAKE AND AIR SYSTEM PA1564 21 FIGURE 38 AIR OPERATED BRAKING SYSTEM WE...
Page 380: ...Section 12 BRAKE AND AIR SYSTEM PA1564 22 FIGURE 39 AIR OPERATED BRAKING SYSTEM W5...
Page 387: ...Section 12 BRAKE AND AIR SYSTEM PA1564 29 FIGURE 46 ABS 6S 5M CONFIGURATION...
Page 418: ...16 BW2158 Honeywell Commercial Vehicle Systems Company 4 2001 Printed in USA...
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Page 1086: ...Section 22 HEATING AND AIR CONDITIONING PA1564 18 FIGURE 17 DOUBLE SWEEP EVACUATION SET UP...
Page 1118: ...Section 22 HEATING AND AIR CONDITIONING PA1564 50 FIGURE 54 HEATER LINE SHUTOFF VALVES WE...
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Page 1125: ...Compressor 62 11052 Rev A WORKSHOP MANUAL for MODEL 05G TWIN PORT COMPRESSOR R...
Page 1126: ...WORKSHOP MANUAL COMPRESSOR MODEL 05G TWIN PORT...
Page 1149: ...Compressor 62 11053 Rev B SERVICE PARTS LIST for MODEL 05G TWIN PORT COMPRESSOR 1 2 3 4 5 6 R...
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Page 1223: ...Section 26 XLII SLIDE OUT PA1564 11...
Page 1224: ...Section 26 XLII SLIDE OUT PA1564 12 FIGURE 16 KEYLESS BUSHING INSTALLATION INSTRUCTION...