Fuel Injection System Pressure Control via Preliminary Action
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The common rail fuel injection system for diesel engines faces challenges in precisely and quickly controlling the high-pressure pump to maintain target pressure, often resulting in overshooting or hunting due to pressure deviations.
Innovation Solution
A fuel injection system that includes a pump, fuel accumulator, pressure sensor, and controller, which determines the required and actual fuel quantities to bring the accumulator pressure in line with the target pressure, using feedback to adjust pump operation and avoid unnecessary valve operations, ensuring stability without overshooting or undershooting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the pump control starts after pressure deviation occurs using PID algorithm, then the system responds to pressure changes, but the actual pressure overshoots or hunts around the target pressure
Solution Approach 1:
The controller calculates the required pump discharge quantity in advance based on the difference between current and target pressure, before actual pressure deviation occurs. This preliminary calculation allows the system to prepare the appropriate fuel quantity upfront, preventing overshooting and hunting while maintaining quick response to pressure changes.
2Manufacturing precision
If the pump discharge quantity is controlled based on pressure deviation, then the pressure control is implemented, but the control precision and quick response are difficult to achieve
Solution Approach 1:
The controller continuously monitors the actual pressure in the common rail and compares it with the target pressure, calculating the required pump discharge quantity based on the pressure difference. This feedback mechanism enables precise pressure control while maintaining quick response by adjusting the pump discharge in real-time according to actual pressure conditions.
Solution Approach 2:
The system calculates the required fuel quantity in advance based on the pressure difference between current and target states, allowing the pump to discharge the precise amount of fuel needed without waiting for pressure deviation to fully manifest, thus achieving both precision and speed.
3Adaptability or versatility
If the target pressure changes with engine operating condition, then the system adapts to different conditions, but the actual pressure overshoots or hunts around the new target pressure
Solution Approach 1:
When the target pressure changes with engine operating conditions, the controller immediately calculates the required pump discharge quantity based on the new target pressure and current pressure state. This preliminary calculation ensures the pump discharges the appropriate fuel quantity to reach the new target pressure without overshooting or hunting, maintaining stability during transitions.
Data Source
AI summary
A fuel injection system for an internal combustion engine is provided which calculates the quantity of fuel required to bring the pressure in a fuel accumulator into agreement with a target pressure and then control an operation of a high-pressure pump based on the required quantity. Even in the absence of a change in pressure in the accumulator, the system controls the high-pressure pump based on the required quantity. Specifically, the system calculates a feedback fuel quantity required to compensate for a difference between the required quantity and a quantity of the fuel actually supplied to the accumulator, in other words, leans such a quantity difference to correct the required quantity, thus resulting in an enhanced response of the system to control the high-pressure pump to a change in pressure in the accumulator.