Gear-Driven Fuel Pump Timing Verification
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Solution Overview
Problem
Incorrect installation of gear-driven fuel pumps in fuel injected IC engines can lead to unstable fuel rail pressure and limited maximum flow rate due to incorrect pump timing relative to engine timing, necessitating a method to verify correct pump gear installation in-situ during engine maintenance or new engine checks.
Innovation Solution
A diagnostic apparatus and method using a computer connected to the engine, programmed to provide pumping events and disable overlapping injectors, measuring fuel rail pressure at specific crank angles to determine if the pumping event occurred at the desired engine crank angle, thereby verifying correct pump gear installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fuel pump installation methods are used without verification, then installation speed is maintained, but pump timing accuracy deteriorates leading to unstable fuel rail pressure and limited maximum flow rate
Solution Approach 1:
The patent applies preliminary action by performing a verification test before final acceptance of the fuel pump installation. The test procedure measures fuel rail pressure at specific crank angle positions to confirm correct pump timing before the engine is returned to service, preventing future performance issues.
Solution Approach 2:
The patent replaces mechanical verification methods with electronic/digital measurement and control systems. A computer system with software controls the test sequence, automatically measures pressure readings at precise crank angle positions, and determines whether pump timing is correct based on predetermined criteria, eliminating manual verification errors.
2Measurement precision
If in-situ testing is implemented to verify pump installation, then installation verification accuracy is improved, but testing complexity and time requirements increase
Solution Approach 1:
The patent applies universality by designing a test system that can verify pump installation on any fuel-injected IC engine regardless of the specific engine type. The computer-controlled system with standardized pressure measurement and crank angle sensing provides a universal solution that adapts to different engine configurations without requiring engine-specific custom equipment.
Solution Approach 2:
The patent applies self-service by enabling the verification test to be performed in-situ on the installed fuel pump without removing the pump or disassembling the fuel system. The test uses the engine's existing fuel injection system, fuel rail, and sensors to conduct the verification, eliminating the need for separate test benches or specialized removal procedures.
3Measurement precision
If multiple pressure measurements are taken at different crank angles, then timing detection accuracy is improved, but measurement time and test duration increase
Solution Approach 1:
The patent applies periodic action by measuring fuel rail pressure at multiple discrete crank angle positions (e.g., 30° before TDC, TDC, and 30° after TDC) during a single engine rotation cycle. This periodic sampling approach efficiently captures the pressure profile needed to determine pump timing accuracy without requiring multiple complete engine cycles or extended test durations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate in-situ verification of correct gear-driven fuel pump installation, reducing time and cost by ensuring proper timing and preventing issues with fuel rail pressure stability and flow rate, and can adjust for misalignment by trimming the pump valve timing angles.
Implementation Method 1
a pump element pumping event is provided
Implementation Method 2
overlapping injectors are disabled during a test period surrounding the pumping event
Implementation Method 3
measuring the pressure in the rail at least two engine crank angles surrounding the pumping event during the test period
Data Source
AI summary
Methods and apparatus are disclosed for detecting whether a gear-driven fuel pump has been installed correctly in a fuel injected IC engine, the pump gear being driven by an engine gear to provide fuel to injectors via a fuel rail. The method may include providing a pump element pumping event. The method may also include disabling overlapping fuel injectors and overlapping pumping events during the test period surrounding the selected pumping event, and measuring the pressure in the rail during the pumping event with the overlapping injectors disabled, the at least two different engine crank angles surrounding the pumping event. The method also may further include determining from the measured rail pressures whether the pumping event occurred at a desired engine crank angle. Apparatus to carry out the methods may include a computer programmed for controlling the sequence of the providing, disabling, measuring, and determining functions, as well as software for carrying out the respective functions.