Fuel Pump Motor Speed Control for Vapor Lock Suppression
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Solution Overview
Problem
Existing fuel pump controllers face challenges in reliably recovering a fuel pump from a vapor lock state, where the fuel pump cannot discharge fuel due to vapor inside, leading to unreliable fuel pumping operations.
Innovation Solution
A motor control device is designed to detect signs of vapor lock and reduce vapor inside the fuel pump by adjusting the motor's rotation speed. This device includes a sign detection unit to identify vapor lock conditions and a vapor suppression unit to mitigate vapor accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fuel pump operates at high rotation speed to maintain fuel supply, then fuel delivery capability is improved, but vapor generation inside the fuel pump increases leading to vapor lock
Solution Approach 1:
The motor rotation speed is dynamically adjusted based on operating conditions. The control device monitors fuel pressure and motor current, and varies the rotation speed to maintain fuel supply while minimizing vapor generation. This dynamic adjustment resolves the contradiction by allowing high speed when needed for fuel delivery and reducing speed when vapor lock risk increases.
Solution Approach 2:
The invention changes the operational parameters (rotation speed, duty cycle) of the fuel pump motor based on detected conditions such as fuel pressure and current characteristics. By modifying these parameters in response to vapor lock indicators, the system maintains productivity while suppressing harmful vapor generation.
2Reliability
If the fuel pump operates continuously to maintain fuel pressure, then fuel supply reliability is improved, but the risk of vapor lock increases due to prolonged operation
Solution Approach 1:
The control device implements periodic monitoring of fuel pressure and motor current to detect early signs of vapor lock. By using periodic detection and intermittent control adjustments rather than continuous operation, the system maintains fuel supply reliability while reducing cumulative vapor generation that leads to vapor lock.
Solution Approach 2:
The system uses feedback from fuel pressure sensors and motor current measurements to continuously monitor pump operation. When vapor lock signs are detected through feedback analysis, the control device adjusts rotation speed or operation cycles to prevent vapor accumulation, thereby maintaining reliability while suppressing vapor lock risk.
3Object-affected harmful factors
If the motor rotation speed is reduced to minimize vapor generation, then vapor lock is suppressed, but fuel delivery capability decreases
Solution Approach 1:
Rather than maintaining a fixed low rotation speed, the system dynamically adjusts speed based on real-time conditions. When vapor lock risk is detected, rotation speed is reduced to suppress vapor generation. When vapor lock is suppressed and fuel demand requires it, speed is increased to maintain delivery capability. This dynamic approach resolves the contradiction by allowing both low and high speed operation as conditions require.
Data Source
AI summary
A motor control device configured to control a motor that drives a fuel pump includes a sign detection unit and a vapor suppression unit. The sign detection unit is configured to detect a sign of a vapor lock that is an abnormality in which the fuel pump is unable to discharge a fuel due to a vapor inside the fuel pump. The vapor suppression unit is configured to change a rotation speed of the motor to reduce the vapor inside the fuel pump when the sign detection unit detects the sign of the vapor lock.