Internal Combustion Engine Cam Profile Control for Cylinder Consistency
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Solution Overview
Problem
Internal combustion engines face drivability and exhaust emission performance deterioration due to inconsistent valve-driving cam profiles between cylinders or cylinder groups, especially during cam switching operations.
Innovation Solution
A control device that performs a second cam switching operation to revert valve-driving cam profiles to the original profile if the first switching operation fails, ensuring consistency across all cylinders or cylinder groups, and includes a malfunction indicator for notifying the driver if the threshold of failures is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cam switching operation is performed to switch valve-driving cam profiles, then the engine can adapt to different operating conditions, but the probability of profile inconsistency between cylinders increases
Solution Approach 1:
The control device monitors the actual cam profile switching status of each cylinder and uses this feedback information to determine whether to perform a reversion switching operation. This feedback mechanism ensures that profile inconsistencies are detected and corrected, maintaining reliability while enabling adaptability.
Solution Approach 2:
The control device performs a preliminary check to determine whether a cam profile switching operation has been successfully completed before proceeding with normal operation. This preliminary action prevents inconsistent profiles from affecting engine performance and allows for corrective reversion switching if needed.
2Productivity
If cam profile switching is implemented to improve engine performance, then drivability and emission performance can be optimized, but the risk of profile inconsistency between cylinders increases
Solution Approach 1:
The control device uses feedback from profile switching status detection to determine when reversion switching is needed, ensuring that performance optimization is maintained without allowing harmful inconsistencies to develop between cylinders.
Solution Approach 2:
The control device prepares for potential switching failures by having a reversion switching operation ready to restore consistent profiles. This cushioning measure prevents drivability and emission problems before they can occur.
3Adaptability or versatility
If the cam switching device switches profiles for all cylinders, then adaptability is improved, but the complexity of controlling consistent switching across all cylinders increases
Solution Approach 1:
The control device handles each cylinder's cam profile switching independently, determining and executing switching operations for each cylinder separately. This segmentation approach simplifies the control logic compared to managing all cylinders simultaneously, reducing overall system complexity while maintaining adaptability.
Data Source
AI summary
A control device is configured, if, although the control device has caused a cam switching device to perform a first cam switching operation for switching the profiles of all the valve-driving cams of a plurality of cylinders from a first profile to a second profile, the profiles of all the valve-driving cams of the plurality of cylinders do not coincide with the second profile, to cause the cam switching device to perform a second cam switching operation for switching the profile of the valve-driving cam for at least one or more normal cylinders that are one or more cylinders at which the switching of profiles to the second profile has succeeded.