High Quality Delivery Valve FZ5BQ Diesel Engine Spare Parts

Abstract:

The delivery valve spring is a critical component in high-pressure fuel injection pumps, directly determining the valve’s opening and closing dynamics, fuel pressure recovery, and system stability. Improper selection of spring stiffness or preload can cause delayed valve response, pressure oscillations, and injection quantity deviation. To address these issues, this study investigates the influence of delivery valve spring parameters on the dynamic response of the fuel injection system through simulation and experimental validation.

A coupled fluid–mechanical dynamic model of the delivery valve assembly was developed, incorporating the nonlinear characteristics of the spring, valve mass, hydraulic damping, and fuel compressibility. The governing equations were solved using the Runge–Kutta method to analyze transient valve lift, response time, and corresponding pressure waveforms under different spring stiffness (12–28 N/mm) and preload levels (0.5–2.0 N).

Results show that increasing spring stiffness reduces valve lift amplitude and shortens closing time, effectively suppressing backflow and secondary pressure peaks. However, excessive stiffness leads to premature closure, resulting in pressure overshoot and unstable injection timing. Conversely, moderate preload improves response linearity and enhances damping stability, while excessive preload delays initial valve opening and causes injection delay at low-speed operation.

An optimal parameter window was identified, where spring stiffness of 18–22 N/mm and preload force of 1.0–1.2 N achieve the best trade-off between rapid response and pressure stability. Under these conditions, simulation and test results show a 15–20% reduction in pressure fluctuation amplitude and a 10% improvement in response consistency compared to standard configurations.

The study further establishes an empirical relationship between spring parameters and dynamic performance indices:

$tr=k1Ks-0.42+k2Fp0.28,\Delta P=k3Ks0.35-k4Fpt\_r\; =\; k\_1\; K\_s^\{-0.42\}\; +\; k\_2\; F\_p^\{0.28\},\; \backslash quad\; \backslash Delta\; P\; =\; k\_3\; K\_s^\{0.35\}\; -\; k\_4\; F\_p$

tr​=k1​Ks−0.42​+k2​Fp0.28​,ΔP=k3​Ks0.35​−k4​Fp​

where
$trt\_r$

tr​ is the response time,
$\Delta P\backslash Delta\; P$

ΔP the pressure fluctuation,
$KsK\_s$

Ks​ the stiffness, and
$FpF\_p$

Fp​ the preload force.

This research provides a theoretical foundation and practical guidance for optimizing delivery valve spring design, enabling enhanced dynamic response, pressure stability, and injection precision in next-generation high-pressure fuel systems.