Electric Motor Current Monitoring for Liquid Detection in Combustion Engines
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Solution Overview
Problem
Internal combustion engines face damage due to undetected liquid in cylinders, which increases cylinder pressure and can lead to component damage, and existing detection methods are complex and inefficient.
Innovation Solution
A liquid detection system using an electric motor to rotate the crankshaft, a frequency converter to supply power, a measuring sensor to measure current and torque, and a control unit to compare these measurements with threshold values, stopping the motor if excessive values are detected, thereby preventing engine damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cylinder specific sensor system is used to detect liquid leakage, then detection capability is improved, but device complexity and installation difficulty increase
Solution Approach 1:
The invention extracts the detection function from complex cylinder-specific sensor systems and relocates it to the electric motor's existing current measurement system. By measuring current consumption during compression strokes, the system detects liquid presence without adding external sensors to each cylinder, thus maintaining detection capability while reducing overall system complexity
Solution Approach 2:
The invention makes the electric motor serve multiple functions: it acts as both the actuator for rotating the crankshaft and as the detection sensor for liquid presence. The same motor that drives the engine compression also provides the current measurements needed for liquid detection, eliminating the need for separate detection hardware
2Reliability
If indicator valves or photoelectric sensors are installed around cylinders, then liquid leakage detection is improved, but ease of installation deteriorates due to repetitive actions and lack of space
Solution Approach 1:
The invention removes the need for external indicator valves and photoelectric sensors by extracting the detection function to the electric motor's control system. This eliminates repetitive installation actions around multiple cylinders and resolves space constraints by using the motor's existing measurement capabilities
Solution Approach 2:
The electric motor's control system performs self-detection by monitoring its own current consumption during compression strokes. The system uses its inherent operational data to detect liquid presence, eliminating the need for separate detection components and simplifying installation
3Reliability
If existing engines are upgraded with complex leakage detection systems, then detection capability is improved, but upgrade complexity increases
Solution Approach 1:
The invention enables existing engines to gain liquid detection capability by integrating it with the electric motor's existing control system. The motor's control unit, which already manages motor operation, now also performs liquid detection through current analysis, avoiding the need for separate detection hardware and reducing upgrade complexity
Solution Approach 2:
The system uses feedback from the electric motor's current measurements to detect liquid presence. The control unit continuously monitors current consumption during compression strokes and compares it against expected values, providing real-time detection without additional hardware complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This system reliably detects liquid in cylinders by measuring current and torque, preventing engine damage through early detection and controlled shutdown, and is simpler to install than existing solutions.
Implementation Method 1
a measuring sensor to measure current of the electric motor
Implementation Method 2
a frequency converter to supply power to the electric motor
Implementation Method 3
an electric motor to rotate a crank shaft of the internal combustion engine
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention concerns a liquid detection system of an internal combustion engine (1) to detect undesired liquid in at least one cylinder of the engine. The system comprises an electric motor (4) to rotate a crank shaft (2) of the internal combustion engine (1), a frequency converter (6) to supply power to the electric motor, a measuring sensor (9) to measure current of the electric motor, and a control unit (8) to receive measurements of the measuring sensor (9). The control unit (8) is arranged to stop the electric motor (4) if the measurement value exceeds a threshold value.