Description
Product Overview
The plunger pair is the core component of the mechanical fuel injection pump that generates high-pressure fuel. The cam mechanism drives the plunger to reciprocate and slide, and the head boss and the side oil return hole cooperate to complete the oil suction, pressure application, and oil return cycle, precisely controlling the fuel injection volume of a single cylinder. Under long-term mining and construction conditions where the engine is subjected to 24-hour high-temperature and heavy-load operations, along with the erosion of hard impurities in diesel, the outer wall of the plunger will wear and the sealing gap will expand. This may result in a continuous decline in the plunger pressure, excessive differences in fuel supply among cylinders, causing engine acceleration weakness, idle vibration, delayed cold start, and black smoke emission. This product features an integrated precision plunger, which is completed with high-pressure pressure retention and uniformity of multi-stage operation fuel supply during factory production. The dimensions are standardized, and disassembly and assembly do not require grinding for adaptation. It is suitable for maintenance of direct injection oil pumps of medium and heavy-duty trucks, agricultural tractors, wheeled loaders, and heavy-duty construction machinery with straight-line oil pumps.
Unique Core Advantages of the Single Product
Head engagement adjustment boss for synchronous oil volume adjustment with precise linearity
The front end of the plunger is integrally formed with an engagement boss, which precisely fits with the oil volume adjustment gear ring of the oil pump. The rotation is synchronous without slipping, and the control of oil and pressure relief is smooth and balanced under high and low loads, reducing the differences in fuel injection volume among cylinders and eliminating acceleration jolts and obvious exhaust color differences.
Multi-stage stepped smooth plunger rod, stable coaxial reciprocation
The plunger rod adopts a multi-stage arc transition stepped structure, with no skew or unilateral wear during the reciprocating motion in the pump barrel. The fuel supply stroke is constant under long-term bumpy vehicle operation, and the idle operation is more stable.
Side edge of the base for fuel return drainage holes, smooth fuel circulation and less carbon deposition
The precise return drainage holes are precisely set on the rear side of the base. The response for pressure relief and oil return is rapid, and the diesel continuously circulates to wash the oil circuit, reducing the accumulation of gums and impurities, and reducing the frequency of plunger sticking and fuel supply interruption faults.
Thickened rear end bearing limit base for anti-high-frequency impact and less deformation
The widened and thickened rear bearing base can withstand the high-frequency reciprocating impact of the reset spring, and is less likely to bulge or deform over long-term use. It can stably maintain the micrometer-level sealing gap between the plunger and the pump barrel, eliminating the leakage and pressure loss of high-pressure fuel inside.
Overall nitrided and hardened alloy steel, wear-resistant and corrosion-resistant, suitable for harsh working conditions
The entire plunger is processed with high-hardness alloy steel, with surface nitriding hardening + mirror finish grinding treatment. The outer wall is smooth and wear-resistant, resisting the hard impurities of diesel and long-term high-temperature erosion, reducing scratches and abrasions, and extending the service life of the parts.
Application Scenarios
Suitable for medium and heavy-duty freight trucks, agricultural tractors, wheeled loaders, and large power fixed diesel generators that are equipped with mechanical direct injection fuel supply systems. Suitable for the maintenance of fuel injection pumps of heavy-duty diesel engines in mining and construction sites operating at full load for 24 hours, with long-term high-temperature and heavy dust in the engine compartment.
Product Basic Parameters
Product Name: Fuel Injection Pump Plunger Pair
Part Number: A741
Main Material: Overall Nitrided and Hardened Alloy Steel
Structural Characteristics: Head engagement adjustment boss, multi-stage stepped plunger rod, side edge return drainage holes, rear thickened bearing limit base
Application Conditions: 24-hour continuous full load, long-term high-temperature in the engine compartment, outdoor high dust heavy-duty mechanical diesel engine fuel injection pump
Product Status: New precision plunger pair, factory completed with calibration and testing of mating clearance, high-pressure sealingity, and fuel supply stroke
Packaging: Each unit is separately packaged in an independent transparent hard protective tube. The ends of the plunger are equipped with plastic plugs for protection, preventing scratches on the precise sliding surface during transportation. Supports single-piece, multi-box, and bulk purchase in single-piece, multi-box, and full-case batches, suitable for cross-border small package / full-case logistics.
