Engine diesel (part2) the fuel circuit

Summary

This video provides an in-depth explanation of the diesel fuel supply system, including its components and circuits. It covers the role of the fuel tank, filter, low and high pressure pumps, injection rail, and injectors. The video also discusses the importance of cleanliness to prevent contamination in the system, methods to manage fuel temperature and pressure, and the operation of the low and high pressure circuits. Detailed explanations about water detection, fuel heating, and priming techniques for maintenance are also included. The system's pressure regulation and safety measures are thoroughly explained to ensure optimal engine performance.

Takeaways

• 😀 The diesel fuel supply circuit consists of a fuel tank, filter, low-pressure pump, high-pressure pump, injection rail, and injectors.
• 😀 The fuel tank stores the fuel, while the filter ensures the removal of impurities to protect sensitive components.
• 😀 The low-pressure pump extracts fuel from the tank and supplies it to the high-pressure pump.
• 😀 The high-pressure pump delivers fuel under high pressure to the injection rail, which stores it and supplies the injectors.
• 😀 Injectors spray fuel into the combustion chambers to facilitate engine operation.
• 😀 The diesel fuel supply circuit includes three primary circuits: low pressure, high pressure, and return circuits.
• 😀 Cleanliness is crucial throughout the diesel fuel supply circuit to prevent damage to the system. Contamination must be strictly avoided.
• 😀 Water in diesel fuel can cause damage, but the filter housing collects water, which can be drained using a bleed screw.
• 😀 Diesel fuel may need to be heated during cold weather conditions through an electrical resistor or return circuit loop.
• 😀 Some vehicles use electric low-pressure pumps to prime the mechanical pump or to replace it, and a priming bulb can manually purge the fuel system.
• 😀 The high-pressure fuel circuit involves a pump, injection rail, and injectors, with pressure regulation achieved by controlling fuel flow and leakage at the high-pressure pump outlet.

Q & A

What is the role of the diesel fuel tank in the fuel supply circuit?

The role of the diesel fuel tank is to store the fuel for the engine.

How does the diesel fuel filter contribute to the fuel system?

The fuel filter retains any impurities contained in the diesel fuel, preventing damage to delicate circuit components.

What function does the low pressure pump serve in the fuel supply circuit?

The low pressure pump draws fuel from the fuel tank and supplies it to the high pressure pump.

What is the purpose of the high pressure pump in the diesel fuel system?

The high pressure pump supplies the injection rail with fuel under high pressure, enabling efficient fuel injection into the combustion chambers.

What are the three circuits in the diesel fuel supply system?

The three circuits are the low pressure circuit, the high pressure circuit, and the return circuit.

Why is cleanliness crucial in the diesel fuel supply system?

Cleanliness is crucial because contaminants entering the fuel system can cause damage to or destroy sensitive components like the injectors.

How is water in diesel fuel managed in the fuel filter?

The filter housing collects water because it is heavier than diesel, and a bleed screw is used to drain it. Some systems also have a water detection sensor.

What is the purpose of heating the diesel fuel in cold temperatures?

Heating the diesel fuel helps prevent clogging and ensures smooth operation during cold negative temperatures. This can be done using an electrical resistor or by using the return fuel circuit.

What role does the fuel return circuit play in the system?

The fuel return circuit returns any excess fuel from the high pressure circuit to the fuel tank, and it also helps regulate the temperature of the diesel fuel.

How does the pressure regulation system in the high pressure fuel circuit work?

The pressure regulation system manages the high pressure inside the injection rail using a pressure regulator, which controls leakage at the high pressure pump outlet, and a fuel flow actuator that meters the fuel flow.