High Pressure Fuel Pump Control via Cam-Crank Synchronization
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Solution Overview
Problem
Conventional high pressure fuel pump control systems face instability and emission gas performance issues when applied to internal combustion engines with variable valve timing, particularly in four-cylinder engines with three drive cam noses, due to limitations in camshaft sensor signal modes and cam nose numbers, leading to inconsistent fuel discharge quantity control and unstable fuel pressure.
Innovation Solution
A high pressure fuel pump control system that utilizes camshaft and crankshaft synchronization, along with cam and crank angle detecting means, to adjust the drive timing of the high pressure fuel pump based on cylinder recognition, enabling stable power distribution and emission control even with varying camshaft phases and potential sensor abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the fuel discharge quantity control is performed by controlling the ON/OFF timing of the solenoid valve with the camshaft sensor signal as an origin, then the control precision of the high pressure pump is improved, but the system becomes limited to specific camshaft sensor signal modes and cam nose numbers
Solution Approach 1:
The control system dynamically adapts to different camshaft sensor signal modes (e.g., 1-3-4-2 mode for four-cylinder engines) by detecting the specific mode and adjusting the ON/OFF timing control accordingly. This allows the system to maintain precise control across various engine configurations and variable valve timing states without being limited to a single fixed mode
Solution Approach 2:
The system changes control parameters based on the detected camshaft sensor signal mode and crankshaft position. By adjusting the timing control parameters according to the specific operating conditions and sensor modes, the system achieves both high precision control and broad adaptability across different engine configurations
2Device complexity
If the relative relationship of the camshaft sensor signal and the cam nose for driving the high pressure pump is assumed consistent, then the control calculation is simplified, but the fuel pressure becomes unstable when the relationship changes
Solution Approach 1:
The system incorporates feedback mechanisms by continuously monitoring the actual camshaft position and crankshaft position, and adjusting the solenoid valve ON/OFF timing based on the detected relationship. This feedback loop ensures accurate fuel pressure control even when the relative relationship between camshaft sensor signals and cam noses changes due to variable valve timing or different engine configurations
Solution Approach 2:
The control system performs preliminary detection of the camshaft sensor signal mode and establishes the correct timing relationship before executing fuel discharge control. This preliminary action ensures that the system is properly configured for the specific operating conditions, preventing fuel pressure instability from the outset
3Device complexity
If the number of drive cam noses is reduced to three for a four-cylinder engine, then the device complexity is reduced, but the fuel quantity discharge control cannot be realized and fuel pressure becomes unstable
Solution Approach 1:
The system dynamically determines the appropriate ON/OFF timing for the solenoid valve based on the detected camshaft sensor signal mode and crankshaft position, even with only three drive cam noses. This dynamic adaptation allows the system to achieve stable fuel discharge control with a reduced number of cam noses by precisely calculating the timing based on the specific sensor signal pattern
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
The system achieves stable fuel system operation, improved combustion stability, and enhanced emission gas performance by calculating suitable power distribution phases and adjusting solenoid valve timings, ensuring consistent fuel discharge and pressure control across varying engine conditions.
Implementation Method 1
a camshaft 525 which is driven in synchronization with a crankshaft 507d of the internal combustion engine 507
Implementation Method 2
a cam angle detecting means 511 which generates a cam angle signal in synchronization with rotation of the camshaft 525, and a crank angle detecting means 516 which generates a crank angle signal in synchronization with rotation of the crankshaft 507d
Implementation Method 3
a high pressure fuel pump 1 having a suction stroke and a spill stroke of the high pressure fuel pump in synchronization with the rotation of the camshaft 525, and/or a spill stroke of the high pressure fuel pump and changes an effective stroke by driving a solenoid valve 8 in the high pressure fuel pump 1
Data Source
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AI summary
There is provided a high pressure fuel pump control system for an internal combustion engine (507) which enables fuel pressure control with high precision without being restricted by the number of cylinders (507b) of the internal combustion engine or the number of phase sensor signals and the number of cam noses which vertically drives a plunger (2) of a high pressure fuel pump (1) even when a camshaft phase varies by a variable valve timing mechanism by using the high pressure fuel pump with a solenoid valve (8). The control system has a means which changes an effective stroke by driving the solenoid valve (8) in the high pressure fuel pump (1), and has a means which changes the drive timing of the high pressure fuel pump (1) based on a cylinder recognition value of the internal combustion engine with the cam angle detecting means as an origin.