Diesel Generator Fuel System

Diesel Generator Fuel Supply System: Comprehensive Technical Guide

The fuel supply system is a critical component of diesel generators, directly impacting power output, fuel efficiency, noise levels, and emissions. This system consists of:

Fuel tank
Low-pressure fuel line
Feed pump
Fuel hoses
Fuel filters
Injection pump
Governor
High-pressure lines
Fuel injectors

These components work together to deliver precisely metered fuel into the combustion chamber for optimal air-fuel mixing and combustion.

1. Fuel Tank

Construction:

Fabricated from pressed/welded steel plates with internal anti-corrosion treatment
Internal baffle plates to prevent fuel sloshing/foaming

Features:

Filler neck with integrated strainer
Ventilated cap to prevent vacuum formation
Bottom drain port for sediment removal

Common Failures & Solutions:

Leaking fuel outlet weld: Repair with bronze welding
Sediment accumulation: Flush through drain port using diesel/kerosene
Note: Both issues cause unstable operation or sudden shutdowns.

2. Fuel Feed Pump

I. Function

Maintains fuel circulation in low-pressure circuit

Delivers filtered fuel to injection pump at required pressure (typically 0.2-0.6MPa)

Common types: Piston, vane, and rotary (rotary pumps used in distributor-type systems)

II. Piston-Type Pump Structure

(Standard in 135-series/B-series Cummins generators)
Key Components:

Main assembly:

Pump body
Piston assembly (0.005-0.02mm clearance to bore)
Inlet/outlet check valves with springs

Drive mechanism:

Pushrod with return spring

Roller tappet (maintains contact with camshaft eccentric)

Priming pump:

Manual piston pump

Rubber seals

Operating button

Priming Pump Purposes:

Pre-lubricates system before startup

Bleeds air from fuel lines to prevent unstable operation

III. Operating Principle

1.Camshaft eccentric drives piston reciprocation

2.Creates suction through inlet valve (intake stroke)

3.Pressurizes fuel through outlet valve (discharge stroke)

4.Self-regulates delivery volume based on engine load

IV. Critical Assembly Specifications

Piston clearance: 0.005-0.02mm (excessive clearance reduces flow rate and power output)
Priming pump seals: Must achieve leak-free compression
Valve seating: Check valves require <0.01mm runout

Technical Note: Modern systems often incorporate:

Electronic unit pumps (EUP)

Common rail technology

Adaptive pressure control (10-300MPa variable)

400KVA Cummins Soundproof Yellow