CVT Control Apparatus for Engine Speed Smoothing
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Solution Overview
Problem
Drivers experience a feeling of strangeness due to sudden changes in engine rotational speed caused by auxiliary load torque, and existing control systems compromise fuel economy when smoothing these changes.
Innovation Solution
A control apparatus with an electronic control unit that performs shifting control of a continuously variable transmission to maintain an optimal fuel economy line, applying a smoothing process only when increasing the required output amount to reduce engine rotational speed changes and prevent fuel economy deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a smoothing process is applied to changes in the required output amount for speed ratio control resulting from auxiliary load torque, then driver comfort is improved by reducing sudden engine rotational speed changes, but fuel economy deteriorates due to delayed movement of the operating point onto the optimal fuel economy line
Solution Approach 1:
The control system dynamically adjusts the smoothing application based on the direction of output amount changes. Smoothing is applied when the required output amount increases to reduce driver discomfort, while smoothing is omitted when the required output amount decreases to maintain fuel economy. This dynamic conditional approach resolves the contradiction by adapting the control strategy to the specific operational context.
Solution Approach 2:
The system changes the parameter of smoothing application (from always applied to conditionally applied) based on the direction of output amount correction. By monitoring whether the required output amount is increasing or decreasing, the system selectively applies smoothing only when necessary for driver comfort, thereby preventing fuel economy deterioration while still reducing driver discomfort.
2Use of energy by moving object
If the required output amount for speed ratio control is corrected in accordance with auxiliary load torque, then the operating point of the engine can follow the optimal fuel economy line, but engine rotational speed changes cause driver discomfort
Solution Approach 1:
The control system dynamically switches between two modes: when the required output amount increases, smoothing is applied to reduce engine rotational speed changes and driver discomfort; when the required output amount decreases, smoothing is omitted to maintain fuel economy. This dynamic conditional control resolves the contradiction between fuel economy optimization and driver comfort.
Solution Approach 2:
The system monitors the direction of required output amount changes (increase or decrease) and uses this feedback to determine whether to apply smoothing. This feedback mechanism allows the system to automatically adjust its control strategy to balance fuel economy and driver comfort based on real-time operational conditions.
Data Source
AI summary
In correcting a throttle opening degree for speed ratio control in accordance with an auxiliary load torque, when the throttle opening degree for speed ratio control is corrected in an increasing manner such that an engine rotational speed rises, a smoothing process of changes in a throttle opening degree correction amount is executed. When the throttle opening degree for speed ratio control is corrected in a decreasing manner such that the engine rotational speed falls, the aforementioned smoothing process is not executed.