Manual Transmission Gear Stage Control Device
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Solution Overview
Problem
In vehicles with manual transmissions, the output characteristic map used to adjust engine torque based on gear stage can lead to fluctuations in torque levels due to inaccurate detection of engine speed and vehicle speed, causing discomfort to occupants as the gear stage is frequently updated during clutch engagement, resulting in a 'busy state' of gear stage updates.
Innovation Solution
A control apparatus that optimizes shift timing by limiting gear stage updates to a predetermined period after clutch engagement, ensuring the reliability of the NV ratio calculation gear stage is maintained for a set time before adjusting the throttle opening degree, thereby preventing frequent torque level changes and ensuring stable vehicle operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gear stage is updated frequently based on NV ratio calculation during clutch engagement, then the responsiveness of engine characteristic adjustment is improved, but the reliability of gear stage determination deteriorates due to inaccurate engine speed and vehicle speed detection
Solution Approach 1:
The control device performs preliminary action by determining the gear stage before clutch engagement based on the shift lever position, and then maintains this gear stage determination during the clutch engagement period. This preliminary determination avoids the need for frequent updates during engagement when detection accuracy is poor, thereby resolving the contradiction between responsiveness and reliability.
2Adaptability or versatility
If the output characteristic is adjusted frequently during clutch engagement, then the adaptability to gear stage changes is improved, but the stability of vehicle operation deteriorates due to torque level fluctuations
Solution Approach 1:
The control device applies periodic action by adjusting the output characteristic only after clutch engagement is complete and the gear stage is reliably determined, rather than continuously during engagement. This periodic adjustment pattern ensures stability by avoiding frequent torque changes while maintaining adaptability through timely updates when conditions are appropriate.
3Measurement precision
If the throttle opening degree is changed frequently to match NV ratio calculation gear stage, then the precision of engine output control is improved, but the discomfort to occupants increases due to torque level differences
Solution Approach 1:
The control device applies beforehand cushioning by preventing frequent throttle opening degree changes during clutch engagement, thereby cushioning against the harmful effect of torque level differences that would cause occupant discomfort. This is achieved by suppressing output characteristic adjustments during the engagement period when detection precision is insufficient.
Data Source
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AI summary
A plurality of engine characteristics is stored to change the output characteristic of the engine in accordance with a gear stage established in a manual transmission. A gear stage determination permission timer and a gear stage determination timer each start counting at a time when a clutch apparatus is engaged due to the completion of the shift manipulation. In a period up until the gear stage determination permission timer finishes counting, when a condition where an NV ratio calculation gear stage is different from a map gear stage and the NV ratio calculation gear stage is not changed continues for a period up until the gear stage determination timer finishes counting, the map gear stage corresponding to the NV ratio calculation gear stage is selected, and the engine characteristic corresponding to the map gear stage is extracted so as to change the engine characteristic.