Fuel Pump Cam Phase Synchronization for Engine Noise Reduction
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Solution Overview
Problem
Direct injection internal combustion engines are noisy, especially at low engine speeds due to the high pressure fuel injection, fuel inlet valve opening, and fuel outlet valve opening, which occur at different crank angles, causing noticeable vibration and noise to vehicle occupants.
Innovation Solution
A processor adjusts the cam phase of the high pressure fuel pump to synchronize the opening of the fuel inlet or outlet valve with the fuel injector timing, reducing noise peaks by superimposing these events at low engine speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the fuel inlet valve and outlet valve openings are kept at their conventional timings, then the fuel pump operates efficiently, but the engine produces multiple distinct noise peaks at low speeds that are noticeable to occupants
Solution Approach 1:
The cam phase is made dynamically adjustable based on engine operating conditions. The control system varies the cam phase angle to different positions depending on whether the engine is operating at low or high speeds, allowing the valve timing to adapt to minimize noise during idle and low-speed operation while maintaining conventional efficient timing during normal operation.
Solution Approach 2:
The invention changes the cam phase parameter (timing angle) to superimpose the fuel inlet valve opening and outlet valve opening with the fuel injector opening. By adjusting this temporal parameter, the system combines multiple noise events into a single noise peak, reducing the overall noise perception at low engine speeds.
2Object-affected harmful factors
If the cam phase is adjusted to superimpose valve openings with fuel injector timing, then noise peaks are reduced, but the control system complexity increases
Solution Approach 1:
The control system continuously monitors engine operating parameters (such as engine speed from a crankshaft position sensor) and uses this feedback to determine the appropriate cam phase position. The processor compares current operating conditions against predetermined thresholds and automatically adjusts cam phase accordingly, creating a closed-loop control system that minimizes noise while maintaining simplicity through automated decision-making.
3Productivity
If the fuel pump operates at conventional timing, then the fuel delivery is efficient, but the high pressure fuel injection creates noticeable vibration and noise
Solution Approach 1:
The invention merges the timing events of multiple components (fuel inlet valve, outlet valve, and fuel injector) into a single synchronized event. By superimposing these openings at the same crank angle, the system combines what would normally be three separate noise and vibration events into one consolidated event, reducing the overall impact of vibration and noise while preserving the efficiency of fuel delivery through the pump.
Data Source
AI summary
A method to reduce engine noise in a multi-cylinder direct injection internal combustion engine. The internal combustion engine includes a high pressure fuel pump having both an inlet valve fluidly connected to a fuel source and an outlet valve typically connected to a pressurized fuel rail. In order to reduce engine noise, especially at low engine speeds, the timing of the opening of either the fuel pump inlet valve or fuel pump outlet valve is varied so that it coincides with the opening of the fuel injectors.