Automatic Transmission Shift Control for Engine Braking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional automatic transmission systems require multiple manual downshift operations to achieve multistage downshifting, leading to inefficiencies in engine braking, which can result in inadequate following distance maintenance and increased risk of collisions due to the time-consuming nature of manual downshifting.
Innovation Solution
A shift control device for automatic transmissions that includes a following distance measuring system, accelerator opening measurement, and a target gear stage determination mechanism, allowing for a single downshift instruction to perform a multistage downshift based on the following distance and vehicle conditions, thereby ensuring an appropriate engine brake is applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple manual downshift operations are performed to achieve multistage downshifting, then the desired gear ratio is achieved, but the time required increases significantly
Solution Approach 1:
The system pre-calculates and stores the relationship between following distance and target gear stages. When a downshift is requested, the control unit immediately retrieves the appropriate target gear stage based on the current following distance, eliminating the need for sequential manual operations and achieving instant multistage downshifting.
Solution Approach 2:
The control unit acts as an intermediary between the driver's downshift request and the transmission system. It automatically determines the target gear stage by referencing the pre-stored mapping between following distance and gear stage, thereby mediating the complex decision-making process and enabling rapid multistage downshifting without requiring multiple manual inputs.
2Ease of operation
If downshifting is performed one stage at a time manually, then each shift is precisely controlled, but the overall process takes too long for effective engine braking
Solution Approach 1:
The system enables self-service by automatically determining the target gear stage based on the pre-stored mapping between following distance and gear stage. When the driver requests a downshift, the control unit autonomously selects the appropriate target gear stage and executes the multistage downshift, eliminating the need for repeated manual operations and achieving rapid engine braking response.
Solution Approach 2:
The system pre-establishes the relationship between following distance and target gear stages in advance. This preliminary preparation allows the control unit to immediately determine the correct target gear stage when a downshift is requested, enabling rapid multistage downshifting and effective engine braking without requiring multiple sequential manual inputs.
3Measurement precision
If multiple downshift operations are required to maintain following distance, then precise distance control is possible, but the driver may carelessly approach the front vehicle
Solution Approach 1:
The system continuously monitors the following distance using the distance measuring unit and compares it with the pre-stored mapping between following distance and target gear stages. This feedback mechanism ensures that the appropriate gear stage is selected to maintain a safe following distance, preventing the driver from carelessly approaching the front vehicle while maintaining precise distance control.
Solution Approach 2:
The system pre-stores the relationship between following distance and target gear stages in advance. This preliminary preparation allows the control unit to immediately determine the correct target gear stage when a downshift is requested, ensuring that the appropriate gear is selected to maintain a safe following distance and prevent careless approach to the front vehicle.
Data Source
AI summary
A shift control device for an automatic transmission is provided with an automatic shift mode and a manual shift mode instructed by a manual operation of a driver. The shift control device includes at least one processor and at least one memory including computer program code that cause the shift control device to measure a following distance between an own vehicle and a front vehicle, measure an accelerator opening of an engine, judge whether the measured following distance is equal to or less than a predetermined set value if a downshift is instructed by a manual operation of the driver and the measured accelerator opening is fully closed, and determine a target shift stage based on the following distance if the following distance is equal to or less than the set value. Accordingly, the shift control device downshifts to the target shift stage.