PIN 4211429 - Caterpillar

Illustration 1 g00810714
(1) Aftercooler
(2) Air inlet
(3) Air outlet
(4) Auxiliary water pump
(5) Tube for the coolant supply to the aftercooler
(6) Tube for the coolant return to the thermostatic valve
(7) Thermostatic valve
(8) Tube for the bypass
(9) Tube for the coolant to the customer supplied heat exchanger
(10) Elbow for the coolant return to the auxiliary pump from the customer supplied heat exchanger Aftercooler (1) is located in the center of the vee on top of the engine.For high pressure gas, compressed air from the turbocharger flows into the aftercooler through air inlet (2). For low pressure gas, a compressed mixture of air and fuel flow into the inlet. The air or the air/fuel mixture that is compressed by the turbochargers also becomes warm. The aftercooler cools the air. The cooler air is more dense. This provides more oxygen for combustion.The air passes through the fins of the aftercooler core in order to exchange heat with coolant. For high pressure gas, the cooler air flows out of the aftercooler through air outlet (3) into the carburetor, the throttle body, and the air inlet manifold. For low pressure gas, the cooler air/fuel mixture flows directly through the throttle body to the air inlet manifold.Coolant is supplied to the aftercooler in a circuit that is separate from the jacket water system. The coolant is pumped by auxiliary water pump (4) that is driven by the engine. The auxiliary water pump has a gear that is driven by the lower left front gear group. Gear groups that are high speed, medium speed, and low speed are used in order to maintain a proper speed of the pump's impeller. This will depend on the engine's rated speed. The coolant is pumped to the aftercooler through tube (5). The coolant exits the aftercooler through tube (6) that is connected to thermostatic valve (7).
Illustration 2 g00810770
Water temperature regulator in a cross section view of a thermostatic valve
The thermostatic valve has one inlet, two outlets, and a water temperature regulator. When the coolant is cool, the water temperature regulator is closed. The coolant is routed directly back to the auxiliary water pump through tube (8) for the bypass. The coolant is recirculated through the aftercooler.When the coolant reaches the opening temperature, the water temperature regulator opens. The coolant is routed through tube (9) to a customer supplied heat exchanger. The coolant is returned to elbow (10) on the auxiliary water pump.Different engine applications may use different temperatures for the aftercooler. The different temperatures are listed in Table 1.
Table 1
Operating Temperatures for the Aftercooler's System
Opening Temperature of the Thermostatic Valve's Water Temperature Regulator Temperature of the Air from the Aftercooler
32 °C (90 °F) 43 °C (110 °F)
54 °C (130 °F) 66 °C (150 °F)
70 °C (160 °F) 82 °C (180 °F)