The lower chamber of the pneumatic drive is used to control the air supply to the engine during warm-up. This control stops when the operating temperature of the coolant is reached.
The upper air drive chamber is used to control the air supply to the engine when the engine is idling when the engine is warm. This control begins when you turn on "ignition" and starting the engine. If, on a diesel engine running during warm-up, you remove the vacuum tube suitable for the upper part of the pneumatic actuator, the engine will stall even with the ignition switch on.
The pneumatic valve at the inlet to the intake manifold opens to reduce vibration at idle or when the diesel engine is stopped. It also opens halfway when the system malfunctions to prevent "spacing" diesel.
Electropneumatic changeover valves Electropneumatic changeover valves connect the pneumatic actuator chambers of diesel gas exchange control systems to either atmosphere or vacuum (vacuum).
Resistance test - fig. 8
1. Disconnect the valve connector.
2. Measure the resistance between the valve terminals.
Connector colors - Black / Brown
Resistance at a temperature of 20°C - 38.5-44.5 Ohm
Pic. 9 Checking the resistance between the terminals of electro-pneumatic valves
Operation check - fig. 9
1. Turn off "ignition".
2. Disconnect the valve connector and vacuum hoses.
3. Blow into nozzle 1: the air must exit into filter 2.
4. Connect battery power to valve terminals.
5. Blow into port 1: the air must come out through port 3.
Pic. 10 Checking the operation of electro-pneumatic valves