Schematic Diagram of the Compressed Air Starter System Using an Air Distributor. It consists of a hand-operated air compressor, air storage cylinder, starter control valve, starter valve, air distributor, charging valve, and safety valve. (1) Compressed Air Starting Process When starting the diesel engine, open the starter switch on the air cylinder. Compressed air from the cylinder flows through the starter control valve to the air distributor and into the diesel engine cylinders. To facilitate starting and conserve compressed air, manually rotate the crankshaft beforehand to position any cylinder's piston at 10°–15° past top dead center (indicated by markings on the flywheel rim). Then open the starting control valve to direct compressed air to the corresponding cylinders via the distributor, driving the pistons downward to initiate the starting process. Open the throttle 1/2 to 1/3. Upon hearing combustion sounds within the engine cylinders, immediately close the start switch and the air cylinder's start valve to transition the engine to low-speed operation. At this point, recharge the air bottle for the next start. Open the return bolt of the first cylinder's fuel injector and the charging valve on the air bottle. Then open the charging valve rod on the first cylinder head to charge the air bottle. When the pressure gauge on the air bottle reaches (2450–2940) kPa, close all valves and switches on the charging lines. Finally, tighten the fuel injector return bolt to bring the first cylinder into operation.
(2) Compressed Air Tank Structure. The tank head features multiple valves. The large central valve is the start valve; opening it allows high-pressure air to exit through the right outlet. Opening the purge valve enables removal of contaminants like water and oil via the purge pipe. Opening the charging valve allows fresh compressed air to enter the tank through this valve. The safety valve on the compressed air cylinder prevents hazards from excessive internal pressure. A spring presses the ball valve tightly against its seat via a spring seat. Pressurized to 2940 kPa (30 kgf/cm²), it is sealed with a lead seal and must not be arbitrarily disassembled or adjusted. When the cylinder pressure exceeds 29 kPa, the safety valve automatically opens, allowing air to escape from the cylinder. This reduces the internal pressure, preventing potential explosion hazards. (3) Air Distributor The air distributor functions to sequentially distribute compressed air to the corresponding cylinder starter valves according to the diesel engine's operating sequence. The outer circumference of the diesel engine air distributor body features six outlet pipe connections, which connect to the starting air pipes of the six cylinders. The shaft 5 is supported by the sleeve 8 in the center of the distributor body. Its front end is connected to the distributor 4, while its rear end is driven by the wheel shaft via the universal joint 10. The end face of the distributor plate has an elongated circular hole. During startup, compressed air enters the distributor through the inlet port. Under air pressure, the distributor plate presses tightly against the distributor body. Driven by the camshaft, the distributor plate rotates, sequentially aligning the elongated hole with each outlet pipe connection. Compressed air is thus delivered to the cylinder starter valves in accordance with the operating sequence. (4) Start Control Valve The start control valve, also known as the start switch, is installed between the air reservoir and the air distributor. Its function is to connect and disconnect the compressed air pathway during startup. During startup, pressing the control valve button lifts the valve plate from its seat, allowing compressed air to enter the air distributor. Releasing the button causes the valve plate to return to its original position under spring force and air pressure, thereby disconnecting the air pathway. (5) Start Valve The start valve is a one-way valve mounted on the cylinder head. During engine startup, it directs compressed air into the cylinder. Once the engine runs, it automatically seals the cylinder, preventing gas from escaping. During startup, high-pressure air from the air distributor overcomes the spring force on the start valve, opening it to allow air into the cylinder. When the compressed air supply is cut off, the valve closes under spring force.
(6) Cylinder Head Inflation Valve The inflation valve, also known as the air extraction valve, is mounted on the first cylinder head. It serves as the control valve for charging the air storage bottle.
To charge the cylinder, first open the bleed-back screw on the injector to stop fuel supply to that cylinder. Then turn the handle to open the charging valve stem on the first cylinder head, allowing charging of the air tank. When the pressure gauge on the air tank reaches (2450–2940) kPa, stop charging and close the charging valve.