Vehicle Torque Control via Variable Rate Limiting
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Solution Overview
Problem
Conventional vehicular driving torque control systems face challenges in improving acceleration response characteristics while minimizing shock during torque increases, particularly in low gear stages, where steep torque variation gradients can lead to unpleasant feelings for occupants due to twist shocks in the drivetrain.
Innovation Solution
A vehicular driving torque control apparatus that implements a variation rate limiting process, setting a low torque side limitation variation rate higher than a high torque side rate until a torque variation rate switching threshold is reached, and then switching to a lower high torque side rate to manage acceleration and reduce drivetrain twist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driving torque variation gradient is made steep to improve acceleration response, then the acceleration response characteristic is improved, but a twist shock occurs in the drive train causing unpleasant feelings for occupants
Solution Approach 1:
The patent applies dynamics by making the variation rate limitation value changeable based on operating conditions. Specifically, the limitation value is adjusted according to the gear stage, allowing steeper torque increase in higher gears (where twist shock is less problematic) and more moderate increases in lower gears (where twist shock is more severe). This dynamic adjustment resolves the contradiction between acceleration response and twist shock reduction.
Solution Approach 2:
The patent changes the parameter of variation rate limitation value based on the gear stage. By setting different limitation values for different gear stages, the system allows faster torque increase in gears where it is tolerable (higher gears) and restricts it in gears where it causes problems (lower gears). This parameter change strategy enables the system to achieve good acceleration response while avoiding twist shock in critical operating conditions.
2Object-affected harmful factors
If the driving torque variation gradient is made moderate to reduce twist shock in low gear stages, then the unpleasant feeling due to shock is reduced, but the acceleration response becomes worsened
Solution Approach 1:
The system dynamically adjusts the variation rate limitation based on gear stage, applying moderate limitation only when necessary (in lower gears where twist shock is problematic) and relaxing it in higher gears. This dynamic approach ensures that acceleration response is not unnecessarily compromised while still protecting against twist shock in critical conditions.
Solution Approach 2:
The patent changes the limitation parameter according to gear stage, allowing the system to optimize between shock reduction and acceleration response for each operating condition. In lower gears, the parameter is set to reduce twist shock, while in higher gears, it is relaxed to improve acceleration response, thus resolving the contradiction.
3Device complexity
If a single variation rate limitation value is used for all torque conditions, then the control system is simple, but it cannot simultaneously achieve good acceleration response and reduce acceleration shock
Solution Approach 1:
The patent segments the torque control into different regions based on gear stage, applying different variation rate limitation values to different segments. This segmentation allows the system to optimize control for each operating condition rather than using a one-size-fits-all approach, thereby achieving both good acceleration response and shock reduction without excessive complexity.
Solution Approach 2:
By changing the limitation parameter based on gear stage, the system achieves adaptive control that responds to different operating conditions. This parameter change approach allows the system to maintain simplicity while improving performance, as it only requires selecting from predefined limitation values based on the current gear stage rather than implementing complex real-time calculations.
Data Source
AI summary
A vehicular driving torque control apparatus, comprising: a limitation variation rate setting section included in a driving torque control section and configured to set, in a form of a limitation variation rate, a low torque side limitation variation rate used in a low torque side until the target driving torque reaches to a torque variation rate switching threshold value and a high torque side limitation variation rate used in a high torque side exceeding the torque variation rate switching threshold value and to execute a limitation suppression variation rate setting process in which the low torque side limitation variation rate is set to be larger than the high torque side limitation variation rate until the target driving torque reaches to the torque variation rate switching threshold value.