CP4 Injection Pump Delivery Valve 149300-0521 Constant-pressure delivery valve assembly

We are a manufacturer for diesel fuel parts, Such as Head Rotor, nozzle, plunger, feed pump,

delivery valve, cam plate, repair kit and so on. Which are applied on Japanese car / truck,

Euro truck and Agricultural machines.

Contact: Ms.Doney
Whatsapp: 008613386901315
E-mail: doney@china-lutong.com

#diesel nozzle fuel nozzle #

#DENSO fuel injection nozzle#

The delivery valve is mounted on the distributive head of injection pump. The valve spring and delivery valve are mounted in the delivery valve holder. The surface of the delivery valve seat is made with high precision. Delivery valves are responsible to separate the high-pressure circuit between the pressure line and the pump plunger. Right after the fuel injection, the nozzle section is adjusted to a specified pressure. That's how the exactly timed closure of the nozzle is secured and undesired dripping is prevented.

Main Function

1. At the end of the plunger’s upward fuel delivery stroke, the delivery valve prevents a reverse flow of fuel from the injection line.

2. Figure 19-24 illustrates the sucking action that occurs at the delivery valve piston portion which controls the residual pressure in the injection line so as to effectively improve the injected spray pattern of the fuel without fuel dribble and possible secondary injection. The sucking action that does occur at the delivery valve therefore effectively reduces the fuel pressure in the injection tube at the end of injection.

China-Lutong is known all over the diesel market for being a twenty years experienced manufacturer of Diesel Injection Spare Parts.

China-Lutong offers delivery valves of highest precision, perfectly designed to control the internal pressure in the injection pump optimally. We produce a wide range of elements, delivery valves and nozzles for fuel injection systems for diesel engines having the following applications: passenger cars, trucks, tractors, agricultural and earthmoving machines and marine engines.

We manufacture new delivery valves for all types of pumps: A, P, and Marine.

A precise manufacture and a strict control of the working schedules are peculiar to our products

China Lutong is one of professional manufacturer engaged in diesel fuel injection system. Our main products include Head Rotor (VE Pump Parts), Injector Nozzle, Plunger, Delivery Valve, Control Valves, Injectors, Cam Disk, Repair Kits,Feed Pump and more.CHINA-LUTONG had honor to get the ISO9001:2015 Certificate

Function of Constant Pressure Delivery Valve

The constant pressure delivery valve is installed above the plunger barrel of the fuel injection pump, at the inlet of the high-pressure fuel pipe. It is a critical component in the diesel fuel injection system. Its core functions are as follows:

1. Maintaining Constant Residual Pressure in the High-Pressure Fuel Pipe (Core Function)

A conventional delivery valve (constant-volume type, with a pressure-relief collar) creates a fixed volume relief when the plunger returns, causing the pressure in the high-pressure pipe to drop rapidly. However, the residual pressure fluctuates with engine speed and load.

The constant pressure delivery valve contains a spring-loaded check valve (ball or cone type). When the pressure in the high-pressure pipe drops below the preset value, the valve closes and prevents further fuel backflow, thereby stabilizing the residual pressure at a constant level (typically 1–3 MPa, depending on the pump model).

2. Preventing Fuel Backflow

During the plunger suction stroke, the delivery valve closes, preventing fuel in the high-pressure pipe from flowing back into the plunger chamber. This ensures accurate fuel delivery for each injection cycle.

3. Eliminating / Reducing Secondary Injection (After-Drip)

This is the biggest advantage of the constant pressure delivery valve. With conventional delivery valves, pressure fluctuations in the high-pressure pipe at high speed and high load can cause the nozzle needle to reopen (secondary injection), leading to after-burning, black smoke, and increased fuel consumption. By stabilizing residual pressure, the constant pressure delivery valve reduces pressure fluctuation amplitude and effectively prevents secondary injection.

Diesel Fuel Injector Nozzles Introduction
Design of the diesel fuel injector nozzle is critical to the performance and emissions of

modern diesel engines. Some of the important injector nozzle design parameters include

details of the injector seat, the injector sac and nozzle hole size and shape. These features

not only affect the combustion characteristics of the diesel engine, they can also affect the

stability of the emissions and performance over the lifetime of the engine and the mechanical

durability of the injector.

All nozzles must produce a fuel spray that meets the requirements of the performance and

emissions goals of the market for which the engine is produced regardless of details of the

fuel system design (i.e., regardless if the fuel system is of the common rail, unit injector,

unit pump or pump-line-nozzle type). Additionally, specific requirements for injection

nozzles can also depend on the fuel system type :
• Common rail-nozzle operates under more demanding tribological conditions and must be

better designed to prevent leakage.
• Unit injector/unit pump-pressure pulsing conditions create more demanding fatigue

strength requirements.
• Pump-line-nozzle-hydraulic dead volume must be minimized.