Engine Cam Switching Actuator Current Control
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Solution Overview
Problem
Existing cam switching devices for internal combustion engines face issues with excessive coil current due to temperature changes, potentially leading to overheating of electronic control units and other components.
Innovation Solution
A control device that adjusts the energization of the electromagnetic solenoid actuator to seat the engagement pin on a forward outer peripheral surface, reducing the average electric voltage applied when high currents are detected, and strategically manages the energization timing to prevent excessive coil current increases during cam switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electric voltage applied to the actuator coil is kept constant, then the actuator operation is simple, but the coil current becomes excessively high when coil temperature is low, causing overheating of electronic control units
Solution Approach 1:
The patent applies dynamics by making the actuator control dynamic rather than static. The controller adjusts the duration of energization based on detected coil temperature, changing the control parameter from fixed voltage application to variable duration control. This resolves the contradiction by allowing simple constant voltage operation under normal conditions while dynamically extending energization duration only when temperature indicates high current flow, thus preventing overheating without complicating normal operation.
Solution Approach 2:
The patent implements feedback by having the controller detect coil temperature and use this information to adjust the energization duration. The temperature detection creates a closed-loop control system where the controller continuously monitors coil conditions and modifies actuator operation accordingly. This feedback mechanism prevents excessive current accumulation and overheating while maintaining operational simplicity through automated temperature-based adjustment.
2Reliability
If the energization duration of the actuator is extended to ensure reliable engagement, then the cam switching operation is reliable, but the coil current accumulates heat and causes overheating of electronic control units
Solution Approach 1:
The patent applies dynamics by making the energization duration dynamic rather than fixed. The controller adjusts the energization duration based on real-time coil temperature detection, extending it only when necessary to ensure reliable engagement while preventing excessive heat accumulation. This dynamic adjustment resolves the contradiction between reliability and temperature control by matching energization duration to actual operational needs and thermal conditions.
Solution Approach 2:
The patent implements parameter changes by modifying the energization duration parameter based on coil temperature. Instead of using a fixed energization duration, the system changes this parameter dynamically according to thermal conditions. This parameter adjustment allows the system to achieve reliable engagement when needed while limiting total energy input to prevent overheating, thus resolving the contradiction between reliability and temperature management.
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
The solution effectively prevents excessive coil current increases, ensuring safe operation by managing electric current changes due to temperature variations, thereby preventing overheating and ensuring reliable cam switching operations.
Implementation Method 1
an electromagnetic solenoid actuator which is equipped with an engagement pin engageable with the cam groove, and which is capable of protruding the engagement pin toward the camshaft
Data Source
AI summary
Provided is a control device for an internal combustion engine equipped with a cam switching device including a cam groove provided on the outer peripheral surface of a camshaft and an electromagnetic solenoid type actuator capable of protruding, toward the camshaft, an engagement pin that is engageable with the cam groove. The control device is configured, in causing the cam switching device to perform a cam switching operation, to perform energization of the actuator such that the engagement pin is seated on a forward outer peripheral surface, and to more lower, when an electric current (coil current) flowing through the actuator as a result of the energization is greater, an average electric voltage per unit time applied to the actuator in protruding the engagement pin toward the cam groove from the forward outer peripheral surface.