Variable Valve Control Apparatus Cam Torque Adaptation
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Solution Overview
Problem
Existing control systems for variable valve operating mechanisms in multi-cylinder internal combustion engines fail to optimize control characteristic values according to changes in cam torque during transitions between all-cylinder and reduced-cylinder operations, leading to suboptimal response speed and potential hunting phenomena.
Innovation Solution
A control apparatus and method that sets distinct control characteristic values, including control gains and maintenance values, for each operation mode to match the cam torque conditions of all-cylinder and reduced-cylinder operations, ensuring appropriate settings for the actuator's controlled variables to maintain target valve characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control gain is extremely small with respect to the cam torque, then the actuator drive speed is decreased, but the response speed when the valve characteristic is changed is decreased
Solution Approach 1:
The control gain is made variable rather than fixed, dynamically adjusting based on the operation mode (all-cylinder or reduced-cylinder). This allows the system to optimize the balance between stability and response speed for different operating conditions, resolving the contradiction between control stability and response speed.
2Speed
If the control gain is extremely large, then the actuator drive speed is extremely high, but the actual value of the valve characteristic may overshoot the target value or a hunting phenomenon occurs
Solution Approach 1:
The control gain is dynamically adjusted based on operation mode. In reduced-cylinder operation where cam torque is smaller, a smaller control gain is used to prevent overshoot and hunting, while in all-cylinder operation a larger control gain is used to maintain high drive speed, thus resolving the contradiction between actuator drive speed and control accuracy.
3Quantity of substance
If the maintenance value is extremely small with respect to the cam torque, then the actual value of the valve characteristic is deviated from the target value in the direction in which the cam torque acts, but the actuator is driven to correct the deviation causing the hunting phenomenon
Solution Approach 1:
The maintenance value is made operation-mode-dependent. In reduced-cylinder operation with smaller cam torque, a smaller maintenance value is used to maintain valve characteristic stability, while in all-cylinder operation a larger maintenance value is used to counteract the larger cam torque, preventing deviation and hunting phenomena.
4Quantity of substance
If the maintenance value is extremely large with respect to the cam torque, then the actual value of the valve characteristic is deviated from the target value in the direction opposite to the direction in which the cam torque acts, but the actuator is driven to correct the deviation causing the hunting phenomenon
Solution Approach 1:
The maintenance value is dynamically adjusted according to operation mode. By using a smaller maintenance value in reduced-cylinder operation and a larger one in all-cylinder operation, the system optimizes the balance between counteracting cam torque and preventing hunting phenomena, resolving the contradiction between maintenance value magnitude and valve characteristic stability.
5Adaptability or versatility
If the control characteristic values are not appropriately set according to cam torque changes, then the response speed becomes excessively high or insufficient, or the actual value overshoots the target value or the hunting phenomenon occurs
Solution Approach 1:
The control characteristic values (control gain and maintenance value) are made dynamic and operation-mode-dependent. The control system automatically selects appropriate values based on whether the engine is in all-cylinder or reduced-cylinder operation, ensuring optimal control performance for each mode and resolving the contradiction between control adaptability and control performance.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A control apparatus (26) and a control method for a variable valve operating mechanism (100) are employed for a multi-cylinder internal combustion engine (1) including the variable valve operating mechanism (100) and a valve stop mechanism (24, 25). The variable valve operating mechanism (100) includes a variable mechanism portion that changes a valve characteristic of an engine valve (9, 10), and an actuator (120) that drives the variable mechanism portion. The valve stop mechanism (24, 25) stops opening/closing of the engine valve (9, 10) in at least one cylinder. A controlled variable (DT) for the actuator (120) is set so that an actual value (VT) of the valve characteristic matches a target value (VTp). A control characteristic value used to set the controlled variable (DT), and used to make the actual value (VT) match the target value (VTp) is set in a manner such that when a reduced-cylinder operation is performed, the control characteristic value is different from the control characteristic value when an all-cylinder operation is performed.