Actuator Assembly Backup Capacitor Power Failure Safety
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Solution Overview
Problem
Electrical actuators in large diesel engines face safety issues due to potential power failures, leading to uncontrolled fuel injection and over-speed events, which existing solutions like redundant power supplies and fail-safe devices have not adequately addressed, limiting their widespread adoption.
Innovation Solution
Incorporating backup power capacitors, such as super-capacitors, integrated with the actuator control means to provide independent power for emergency shutdown and ensure the fuel control shaft returns to a safe position in case of power failure, along with power supply detectors and capacitor control electronics for efficient charging and voltage stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical actuators are used to control fuel injection, then performance and reliability are improved and cost is reduced, but safety deteriorates due to potential power failures leading to uncontrolled fuel injection
Solution Approach 1:
The patent implements a safety device that preemptively monitors the electrical power supply to the actuator and automatically actuates the fuel control shaft to a safe position upon detecting power failure, preventing uncontrolled fuel injection before it can occur. This preliminary protective action resolves the contradiction by maintaining safety without requiring redundant power supplies or complex fail-safe mechanisms.
Solution Approach 2:
The patent introduces a mechanical safety device as an intermediary between the electrical actuator and the fuel control shaft. This intermediary mechanism provides a direct mechanical connection that can override the electrical actuator and force the fuel control shaft to a safe position, thereby decoupling the safety function from the electrical system's reliability while preserving the benefits of electrical actuation during normal operation.
2Object-affected harmful factors
If redundant power supplies or fail-safe devices are added to electrical actuators, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the safety function from the complex electrical control system and implements it as a separate, simple mechanical device. This safety mechanism operates independently of the electrical actuator's complexity, providing fail-safe functionality through a straightforward mechanical connection that can directly position the fuel control shaft without requiring redundant power supplies or complex electronic control circuits.
Solution Approach 2:
The patent employs a simple mechanical safety device that is inexpensive and straightforward in design, contrasting with complex redundant electrical power supplies. This mechanical solution provides adequate safety functionality without the high cost and complexity of electrical redundancies, accepting that the mechanical device serves a specific single-purpose safety function rather than being a comprehensive backup system.
3Object-affected harmful factors
If mechanical actuators are used instead of electrical actuators, then safety is improved through continuous power retention, but cost and performance deteriorate
Solution Approach 1:
The patent merges the advantages of both mechanical and electrical actuators by combining an electrical actuator for normal operation with a mechanical safety device for fail-safe protection. This hybrid approach allows the system to benefit from the lower cost and better performance of electrical actuators during normal operation while incorporating the inherent safety of mechanical actuators through the integrated safety mechanism that ensures continuous control capability.
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 solution provides a reliable and cost-effective means to prevent uncontrolled fuel injection by ensuring the actuator assembly can safely shut down the fuel control shaft even during external power failures, enhancing safety and reliability while maintaining a compact design.
Implementation Method 1
backup power in the form of capacitor power arranged to provide power for the actuator control means in case of loss of power or power failure of the electric power supply
Data Source
AI summary
The invention relates to an actuator assembly for controlling fuel injection of a large combustion engine, especially a diesel engine, including an electric motor (6) acting on a control shaft (8) arranged to control the fuel injection and actuator control means (2,3) provided with an electric power supply (4,5) for controlling the electric motor (6). According to the invention the actuator assembly is pro- vided with backup power in the form of capacitor power (12) arranged to provide power for the actuator control means (2,3) in case of loss of power or power fail- ure of the electric power supply (4,5) so as to enable the actuator control means (2,3) to control the electric motor (6) to drive the control shaft (8) to a predefined safe position. (Fig. 1)