Fuel Supply Device Motor Control via Current Detection
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Solution Overview
Problem
Existing fuel supply devices for engines require a fuel pressure sensor to maintain optimal fuel pressure, increasing manufacturing costs and complexity, and fail to accurately control fuel flow rates due to aging changes without this sensor.
Innovation Solution
A fuel supply device that uses a valve in the fuel passage to adjust motor voltage, current, or revolutions based on change points, allowing for correction of these parameters without a fuel pressure sensor, enabling accurate flow rate control through a calculation and correction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fuel pressure sensor is used to maintain optimal fuel pressure, then fuel pressure control accuracy is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The invention extracts and eliminates the fuel pressure sensor from the system by using the existing motor current detection capability to infer fuel pressure conditions. The ECU calculates fuel pressure based on the relationship between motor current and fuel pressure, removing the need for a separate sensing component while maintaining control accuracy.
Solution Approach 2:
The invention introduces motor current as an intermediary parameter to indirectly measure fuel pressure. Instead of directly sensing fuel pressure, the system uses motor current as a mediator that correlates with fuel pressure conditions, allowing pressure control without a dedicated pressure sensor.
2Ease of manufacture
If a fuel pressure sensor is eliminated to reduce manufacturing cost, then manufacturing cost is reduced, but feedback control capability is lost
Solution Approach 1:
The invention establishes a feedback control mechanism using motor current as the sensing parameter. The ECU continuously monitors motor current, compares it with expected values based on fuel pressure requirements, and adjusts motor voltage accordingly to maintain proper fuel pressure, creating a closed-loop feedback system without a pressure sensor.
Solution Approach 2:
The invention changes the control parameter from direct fuel pressure sensing to motor current sensing. By detecting changes in motor current that correspond to different fuel pressure conditions, the system maintains feedback control capability while using an electrical parameter instead of a mechanical sensing component.
3Device complexity
If motor control parameters are not corrected for aging changes, then device complexity is reduced, but fuel pressure control accuracy deteriorates over time
Solution Approach 1:
The invention performs preliminary correction of motor control parameters during a learning phase before normal operation. The ECU detects change points in the motor current-voltage relationship and stores corrected parameters in advance, compensating for aging effects before they significantly impact fuel pressure control accuracy during actual engine operation.
Solution Approach 2:
The system performs self-correction of aging effects by automatically detecting changes in its own motor characteristics and adjusting control parameters accordingly. The ECU monitors motor current, identifies aging-related drift in the current-voltage relationship, and autonomously corrects the stored parameters without external intervention or additional sensors.
Data Source
AI summary
A fuel supply device (1) has a valve (13) in a fuel passage between a fuel pump (3) and an engine (5). In a storage portion of an ECU (18-21) is stored a relationship between a fuel pressure and a flow rate, which are required by the engine, and voltage which is supplied to a motor (7). The ECU senses voltages V26, V27, V28 supplied to the motor from a controller (22) when the valve is opened from change points C1′, C2′, C3′ at which a characteristic between the voltage and the current which are supplied to the motor (7) is changed. Then, the ECU corrects the voltage stored in the storage portion on the basis of differences between voltages V1, V2, V5 stored in the storage portion at the change points C1, C2, C3 and the voltages V26, V27, V28 when the valve is opened. In this way, the fuel supply device can correctly control the motor in correspondence to the fuel pressure and the flow rate which are required by the engine.