Valve Lift Switchover Torque Control via Dual Intake Models
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Solution Overview
Problem
Internal combustion engines face difficulties in maintaining torque neutrality during valve lift switchover due to inaccuracies in absorption coefficient and volumetric efficiency models, leading to engine bucking and increased complexity in engine management systems.
Innovation Solution
A method that uses a basic intake manifold model to determine cylinder charge for normal operation and a switchover intake manifold model for precise calculations during valve lift switchover, incorporating a charge correction model to ensure constant torque by adjusting operating data such as injection time, ignition angle, and throttle position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-precision models are used for valve lift switchover control, then torque neutrality is improved, but device complexity and computational resources are exhausted
Solution Approach 1:
The patent segments the valve lift switchover process into distinct phases: a first operating range where the first valve lift is active, a second operating range where the second valve lift is active, and a transition range where switchover occurs. This segmentation allows the use of simplified models in stable operating ranges and more complex models only when needed during transition, reducing overall computational burden while maintaining torque neutrality during critical switchover moments
Solution Approach 2:
The patent performs preliminary determination of the basic cylinder charge using a first, less complex model before the actual switchover. This preliminary calculation provides a baseline that is then refined during the transition phase, allowing the system to prepare for switchover in advance and reduce the computational complexity required during the critical moment of transition
2Measurement precision
If comprehensive models are used to map all influencing parameters with precision, then torque calculation accuracy is improved, but memory storage capacity and computing capacity are exhausted
Solution Approach 1:
The patent divides the modeling approach into two segments: a first model that handles the majority of operating conditions with reduced complexity, and a second, more comprehensive model that is activated only during the transition range. This segmentation reduces the overall memory storage requirement while maintaining high torque calculation accuracy during critical switchover operations
Solution Approach 2:
The patent changes the level of model complexity based on the operating parameter range. During stable operating ranges, a simplified model with fewer parameters is used. During the transition range, the system switches to a more comprehensive model that accounts for all influencing parameters, thereby optimizing the balance between accuracy and resource consumption
Data Source
AI summary
In one aspect, a method for controlling an internal combustion engine using valve lift switchover is provided. Within the scope of this method, a switchover intake manifold model for the switchover-relevant pressure range for valve lift switchover is applied in addition to the use of a basic intake manifold model. This ensures a valve lift switchover with approximately constant torque of the internal combustion engine.