Transmission Control System Down-Shift Shock Suppression
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Solution Overview
Problem
Existing transmission control systems face challenges in effectively suppressing and preventing shift shock during down-shifting in automatic transmissions, particularly when the electric motor in the electronic throttle system is not operational.
Innovation Solution
A transmission control system that includes a detection device for down-shifting operations, a throttle opening adjustment mechanism, a shift mechanism, and a clutch actuation mechanism, controlled by a controller to manage the throttle valve opening and clutch state, ensuring the engine rotational speed is synchronized with the transmission after gear change, thereby preventing shift shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor in the electronic throttle system is not operational, then the output adjustment of the engine cannot be performed, but the patent provides a fallback mechanism using the guard mechanism and throttle cable to mechanically adjust the throttle valve opening
Solution Approach 1:
The guard mechanism serves as an intermediary component that can transmit mechanical rotation from the throttle grip to the valve stem when the electric motor is non-operational. This intermediary mechanism ensures continuous functionality of the throttle system even when the primary electronic actuation fails.
Solution Approach 2:
The system changes the actuation parameter from electrical (motor-driven) to mechanical (cable-driven) when the motor is not operational. This parameter change allows the throttle valve opening to be adjusted through alternative means, maintaining system reliability.
2Productivity
If the throttle grip is not operated by a driver, then the valve stem rotation is restricted by the guard mechanism, but the patent enables down-shifting control to increase throttle valve opening without driver input
Solution Approach 1:
The controller performs preliminary action by temporarily increasing the throttle valve opening before clutch disconnection during down-shifting. This preliminary throttle opening ensures engine speed is raised in advance to match the lower gear ratio, enabling smooth and rapid down-shifting without driver intervention.
Solution Approach 2:
The transmission control system performs self-service by automatically adjusting the throttle valve opening during down-shifting operations without requiring driver input. The controller autonomously manages the throttle actuator to synchronize engine speed with transmission gear changes, improving shift speed and operational efficiency.
3Object-affected harmful factors
If the engine output is increased at the time of down-shifting, then shift shock is suppressed, but the patent must subsequently reduce engine output to match driver requirements
Solution Approach 1:
The controller performs preliminary action by increasing engine output before clutch disconnection to suppress shift shock. After the clutch disconnects and gear change is complete, the controller then reduces engine output to match driver requirements. This two-stage control sequence effectively eliminates shift shock while maintaining proper power delivery.
Solution Approach 2:
The engine output follows a periodic action pattern during down-shifting: first increased to suppress shift shock, then reduced after gear change to match driver needs. This periodic adjustment of engine torque ensures smooth transition while maintaining control over vehicle dynamics throughout the shifting process.
Data Source
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Figure 3A~3B
AI summary
A transmission control system includes an ECU, a throttle actuator, a clutch actuator, and a shift actuator. The throttle actuator adjusts a throttle opening under control of the ECU, the clutch actuator adjusts a state of a clutch under control of the ECU, and the shift actuator changes a gear position of a transmission under control of the ECU. When the transmission is shifted down, a throttle opening is adjusted to a first value and the clutch is disconnected such that a rotational speed of an engine increases. Then, the gear position of the transmission is moved to a lower position by one stage with the clutch being disconnected. After that, the throttle opening is decreased to a second value, and connection of the clutch is started. The second value is set to a value larger than a minimum value.