Drive Train Shift Control for Ambient Torque Variation
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Solution Overview
Problem
Existing drive train systems in motor vehicles, particularly those with internal combustion engines and self-shifting transmissions, fail to effectively account for variations in ambient air pressure and temperature, leading to torque gaps and pendulum shifts when operating outside reference conditions, resulting in suboptimal performance and driver discomfort.
Innovation Solution
A method that dynamically controls the transmission and internal combustion engine by considering the rotational speed, torque, air pressure, and temperature, using models to predict torque changes and adjust gear shifts accordingly, with communication between control units to optimize shifting processes and incorporate the capabilities of both the internal combustion engine and electric machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transmission is controlled based only on reference state engine torque properties, then the control system remains simple, but torque gaps and pendulum shifts occur when operating outside reference conditions
Solution Approach 1:
The patent applies parameter changes by modifying the transmission control strategy to account for environmental parameter variations (air pressure, air temperature). The system adjusts shift points and transmission ratios based on corrected torque values that compensate for deviations from reference state conditions, thereby maintaining reliable transmission operation across different operating environments without requiring complete system redesign
Solution Approach 2:
The patent implements preliminary action by pre-calculating corrected torque values using stored reference data and current environmental sensors readings. The control unit proactively adjusts transmission control parameters before pendulum shifts or torque gaps occur, preventing these issues rather than reacting to them after they manifest
2Ease of operation
If the transmission shifts at constant wheel speed without considering environmental conditions, then the shifting process is simple, but the driver experiences torque gaps and reduced performance
Solution Approach 1:
The patent implements feedback by continuously monitoring environmental conditions (air pressure, temperature) and using this information to dynamically adjust shift points and transmission control. The system compares actual environmental parameters against reference values and modifies shifting behavior accordingly, ensuring optimal vehicle performance while maintaining smooth, imperceptible shifts for the driver
3Device complexity
If the transmission control unit does not consider air pressure and temperature deviations, then the control algorithm remains simple, but pendulum shifts occur between different transmission ratios
Solution Approach 1:
The control unit proactively calculates corrected torque values using stored reference data and current environmental sensor readings before pendulum shifts occur. By anticipating torque availability changes due to environmental deviations, the system adjusts shift points in advance, preventing the oscillation between transmission ratios
Solution Approach 2:
The system continuously monitors environmental parameters and feeds this information back to the transmission control unit, which dynamically adjusts shift points to maintain stability. This closed-loop control prevents pendulum shifts by adapting transmission behavior to real-time environmental conditions
Data Source
Figure 1
AI summary
The invention relates to a method for operating a drive train (1) in a motor vehicle (2), the drive train (1) having at least an internal combustion engine as a first drive unit (3) and a self-shifting transmission (4), the first drive unit (3) being controlled by means of a first control unit (5) and the transmission (4) being controlled by means of a transmission control unit (6), the transmission (4) being actuated in dependence on at least the rotational speed of the first drive unit (3) and on a first torque that can be provided by the first drive unit (3), characterized in that the transmission (4) is actuated additionally in dependence on the air pressure in the environment (7) of the motor vehicle (2) and on the air temperature in the environment (7) if these parameters deviate from a reference state for the air pressure and the air temperature.