Contents: Idle system ↡ Enrichment of the combustible…↡
Main metering system of the Stromberg 175 CDT carburetor
1 - cap; 2 - piston; 3 - spring; 4 - jet; 5 - needle; 10 - throttle valve
The vacuum created by the engine in the intake manifold enters the cap 1, which ensures the lifting of the piston 2, the pressure under which is equal to atmospheric. As soon as the force created by the vacuum and the force of the spring installed inside the cap 3 are balanced, the position of the piston is stabilized, and it provides access to a certain amount of air and ensures the dosage of fuel sucked in by the jet 4 by means of a conical needle 5, regulating the flow section of the jet 4. The shape of the needle is specially selected to achieve the best dosage of fuel at any position of the piston in the cap.
Idle system
The piston occupies a position that provides minimal access of air and fuel.
Idle speed is adjusted by changing the degree of opening of the throttle valve.
The electromagnetic valve installed in the lower part of the jet blocks the fuel supply to the carburetor when the engine is stopped and if the maximum engine speed is exceeded.
Enrichment of the combustible mixture during acceleration
The oil shock absorber slows down the piston rise under the action of the vacuum in the cap. The vacuum in the intake manifold acts on the jet. This ensures the supply of additional fuel.
Starter for carburetor Stromberg 175 CDT
2 - piston; 6 - valve; 7 - starting device; 8 - ball valve; 9 - thermal valve; 10 - throttle valve; 11 - economizer control lever
Enrichment of the combustible mixture when starting a cold engine is carried out by valve 6 with calibrated holes, ensuring an increase in idle speed (by introducing additional air) and an increase in the amount of incoming fuel.
The movement of the spool is regulated by an electric starting device (time delay heating) and pneumatic drive (due to the vacuum in the intake manifold), the action of which is adjusted depending on the temperature of the coolant. Under the action of the spring, the diaphragm of the starting device 7, which is under the action of atmospheric pressure, opens the ball valve 8, which allows access to the fuel-air mixture, enriched in the valve controlled by the thermostat. After starting the engine, the valve gradually closes, its holes are blocked, limiting the flow of the combustible mixture.
After the engine is started, the thermovalve 9 closes the channel of communication with the atmosphere of the starting device. Under the influence of the vacuum in the intake manifold, the ball valve 8 closes, and the spool 6 rises. Enrichment of the combustible mixture stops.
Original can be found on the website MERCEDESMAN