Fuel Pump Efficiency Control via Pressure Feedback
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Solution Overview
Problem
Internal combustion engines face challenges in efficiently operating fuel-supply systems while minimizing harmful emissions and maintaining cost-effective production, particularly due to pressure fluctuations and wear-related efficiency reductions in high-pressure pumps.
Innovation Solution
A method and device that utilize a high-pressure sensor to determine an efficiency characteristic and flow rate characteristic, limiting the maximum injection quantity of injection valves to prevent pressure falls in the high-pressure fluid accumulator, thereby maintaining efficient operation and reducing emissions, weight, and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the stroke volume of the high-pressure pump is reduced to minimize weight and space requirements, then the pump becomes more compact and cost-effective, but the maximum flow rate decreases which can cause pressure drops in the high-pressure fluid accumulator
Solution Approach 1:
The patent applies dynamics by making the injection quantity adaptive rather than fixed. The control device dynamically adjusts the injection quantity based on real-time pressure measurements from the high-pressure sensor, allowing the system to operate reliably with a compact pump by optimizing fuel delivery according to actual pressure conditions.
Solution Approach 2:
The patent implements feedback control by using the high-pressure sensor to continuously monitor the pressure in the high-pressure fluid accumulator and using this information to determine the maximum injection quantity. This closed-loop feedback ensures pressure stability despite the reduced pump size and flow rate.
2Power
If the maximum injection quantity is increased to meet high torque requirements, then the engine can produce higher power, but harmful substance emissions increase due to inefficient combustion
Solution Approach 1:
The patent changes the parameter of injection quantity from a fixed high value to a dynamically adjusted value based on actual pressure conditions. This allows the system to maintain power output when needed while reducing injection quantity under normal conditions to minimize harmful emissions.
Solution Approach 2:
The patent applies partial action by limiting the injection quantity to the maximum value that actually achieves the desired pressure level, rather than consistently using excessive injection quantities. This prevents over-injection that would lead to incomplete combustion and harmful emissions.
3Reliability
If a larger high-pressure pump is used to maintain sufficient flow rate, then pressure stability is improved, but the device complexity and production costs increase
Solution Approach 1:
The patent replaces the mechanical solution of using a larger, more complex pump with a control-based solution. Instead of increasing pump size to maintain flow rate, the system uses electronic control to adjust injection quantity based on pressure feedback, achieving pressure stability with a simpler, more compact pump design.
4Reliability
If the injection quantity is limited to prevent pressure drops, then pressure stability is maintained, but the engine torque output is reduced
Solution Approach 1:
The patent makes the injection quantity dynamic rather than statically limited. The control device adjusts the injection quantity in real-time based on pressure measurements, allowing the system to maintain pressure stability while providing sufficient torque output when required by operating conditions.
Data Source
AI summary
A method operates a fuel-supply system for an internal combustion engine. The fuel-supply system contains a high-pressure fuel pump, a high-pressure fluid accumulator having a fuel-injection valve, and a high-pressure sensor. A measurement signal of the sensor is representative of a pressure within the high-pressure fluid accumulator. The high-pressure fuel pump is fluidically connected on the outlet side to the high-pressure fluid accumulator. A respective maximum injection quantity of the fuel-injection valve is determined depending on the measurement signal of the high-pressure sensor. The injection quantity is determined depending on an efficiency characteristic representing the efficiency of the high-pressure fuel pump, the efficiency characteristic depending on the measurement signal of the high-pressure sensor. The at least one fuel-injection valve is actuated in such a way that a respective injection quantity to be metered by the at least one fuel-injection valve is limited to the respective maximum injection quantity.