Page 125 - Mechanic Diesel - TT

MECHANIC DIESEL - CITS

3 Float level not set properly.
4 Addling not set properly.
5 Addling should be set very low.
Components
1 Air Intake

2 Venturi
3 Float Chamber
4 Main Jet
5 Idle Circuit

6 Throttle plate
7 Choke
8 Accelerator pump
9 Butterfly valve
10 Fuel inlet
11 Mixture screws

Importance of testing of fuel pumps

Objectives: At the end of this lesson you shall be able to
• explain Importance of testing of fuel pumps.

Fuel Pump: The purpose of the fuel pump is to measure the right amount of fuel according to the load and speed
and deliver it to the cylinder at the right time. A C.A.V fuel pump is shown in Figure, its plunger is operated by a
cam and tappet system. This plunger moves up and down in a barrel. The number of plungers in the engine.
Depends on the number of cylinders. There is a rectangular straight groove on the circumference above the
plunger which is connected to a helical groove at the bottom. The delivery valve rises up on its seat against a
spring due to pressure. Fuel goes to the injector from the delivery valve. Injector injects into the cylinder.
Importance of testing of fuel pump
1 Performance Verification: The test ensures that the fuel pump operates efficiently, delivering the correct
fuel flow rate and pressure to meet engine demands. It helps maintain optimum engine performance and fuel
efficiency.
2 Safety Assurance: Properly functioning fuel pumps prevent fuel leakage and potential hazards such as fire
or explosion. Testing helps identify any issues that could compromise safety.
3 Preventive maintenance: Regular testing enables early detection of wear and tear or potential failure,
enabling timely repair or replacement. This helps prevent unexpected breakdowns and costly repairs.
4 Compliance: Fuel pump testing ensures compliance with regulatory standards and environmental regulations
regarding emissions and fuel efficiency. Meeting these standards is essential for vehicle manufacturers and
operators.
5 Customer Satisfaction: Reliable fuel pump performance contributes to overall vehicle reliability and customer
satisfaction. Testing helps ensure that vehicles deliver the expected level of performance and durability.
In short, testing of fuel pumps is critical to ensuring vehicle safety, performance, compliance and customer
satisfaction.

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CITS : Automotive - Mechanic Diesel - Lesson 29 & 30