REFRIGERATION SYSTEM
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Operation
1. Operation Control Valve
Operation control valve is located in the suction port (low-pressure) side, and opens or closes in response
to changes in refrigerant suction pressure.
Operation of the valve controls the internal pressure of the crankcase.
The angle of the swash plate is controlled between the crankcase's internal pressure and the piston cylin-
der pressure.
2. Maximum Cooling
Refrigerant pressure on the low-pressure side increases with an increase in heat loads.
When this occurs, the control valve's bellows compress to open the low-pressure side valve and close the
high-pressure side valve.
This causes the following pressure changes:
● The crankcase's internal pressure to equal the pressure on the low-pressure side;
● The cylinder's internal pressure to be greater than the crankcase's internal pressure.
Under this condition, the swash plate is set to the maximum stroke position.
3. Capacity Control
● Refrigerant pressure on suction side is low during high speed driving or when ambient or interior tem
perature is low.
● The bellows expands when refrigerant pressure on the suction pressure side drops below approxi
mately 177 kPa (1.8 kg/cm
2 , 26 psi).
Since suction pressure is low, it makes the suction port close and the discharge port open. Thus, crank-
case pressure becomes high as high pressure enters the crankcase.
● The force acts around the journal pin near the swash plate, and is generated by the pressure difference
before and behind the piston.
The drive lug and journal pin are located where the piston generates the highest pressure. Piston pres-
sure is between suction pressure Ps and discharge pressure Pd, which is near suction pressure Ps. If
crankcase pressure Pc rises due to capacity control, the force around the journal pin makes the swash
plate angle decrease and also the piston stroke decrease. In other words, crankcase pressure increase
triggers pressure difference between the piston and the crankcase. The pressure difference changes the
angle of the swash plate.
RHA473C
SERVICE DATA AND SPECIFICATIONS (SDS)
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SERVICE DATA AND SPECIFICATIONS (SDS)PFP:00030
BatteryEKS0031Q
StarterEKS0031R
AlternatorEKS0031S
Applied model QR20, QR25 engine
YD22 engine Except for Northern Europe
For Northern Europe
Standard Option
Type 55D23L 80D26L 110D26L
Capacity V-AH 12-48 12-55 12-64
TypeS114-844 M0T87081 M8T71471
HITACHI make MITSUBISHI make
Reduction
Applied modelQR20, QR25 engine
YD22 engine
A/T M/T
System voltage V12
No-loadTerminal voltage V 11.0
Current A Less than 90 Less than 90 Less than 145
Revolution rpm More than 2,700 More than 2,500 More than 3,300
Minimum diameter of commutator mm (in) 28.0 (1.102) 28.8 (1.134) 31.4 (1.236)
Minimum length of brush mm (in) 10.5 (0.413) 7.0 (0.276) 11.0 (0.433)
Brush spring tension N (kg, lb) 16.2(1.65, 3.64)15.0 - 20.4(1.5 - 2.1, 3.4
- 4.6)26.7 - 36.1(2.7 - 3.7, 6.0
- 8.2)
Clearance between bearing metal and armature
shaft mm (in)Less than 0.2 (0.008) —
Clearance “l” between pinion front edge and pinion
stopper mm (in)0.3 - 2.5 (0.012 - 0.098) 0.5 - 2.0(0.020 - 0.079) —
Movement “l” in height of pinion assembly mm (in) — 0.5 - 2.0(0.020 - 0.079)
TypeLR1110-713 A3TB0771
HITACHI make MITSUBISHI make
Applied model QR20, QR25 engine YD22 engine
Nominal rating V-A 12-110 12-90
Ground polarityNegative
Minimum revolutions under no-load (When 13.5V is
applied) rpmLess than 1,100 Less than 1,300
Hot output current (When 13.5V is applied) A/rpmMore than35/1,300
More than91/2,500
More than110/5,000More than29/1,300
More than76/2,500
More than88/5,000
Regulated output voltage V 14.1 - 14.7
Minimum length of brush mm (in) More than 6.0 (0.236) More than 5.0 (0.197)
Brush spring pressure N (g, oz) 1.0 - 3.43 (102 - 350, 3.60 - 12.34) 4.8 - 6.0 (490 - 610, 17.28 - 21.51)
Slip ring minimum diameter mm (in) More than 26.0 (1.024) More than 22.1 (0.870)
Rotor coil resistance at 20° (68°F) Ω2.31 2.1 - 2.5
