Automatic Gearbox Shift Control Using Exhaust Temperature Prediction
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Solution Overview
Problem
Current methods for controlling automatic transmission shifting in vehicles with internal combustion engines lack precision in predicting engine behavior, particularly torque build-up, which affects fuel efficiency due to the absence of considering the thermal state of engine exhaust system components.
Innovation Solution
Incorporating the current thermal state of engine exhaust system components, such as the exhaust gas turbine, into the predictive calculation of engine behavior to determine adapted switching thresholds for fuel-efficient shifting, using direct temperature measurements or indirect calculations based on engine load profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the engine's behavior is predicted based on standard parameters (engine speed, transmission output speed, accelerator pedal position, brake pedal position, vehicle speed, accelerator pedal velocity, current vehicle mass, and road gradient), then the shifting strategy can be implemented, but the predictive accuracy of torque build-up is insufficient
Solution Approach 1:
The patent applies preliminary action by continuously predicting the engine's torque build-up behavior before actual gear shifts occur. The control unit performs predictive calculations using the current thermal state of exhaust system components to determine optimal shift thresholds in advance, allowing the system to prepare for upcoming shifts rather than reacting to current conditions alone. This enables more accurate prediction of engine behavior during upcoming gear changes.
Solution Approach 2:
The patent implements feedback by continuously monitoring the actual thermal state of exhaust system components (such as turbocharger turbine temperature) and using this information to adjust the predictive model. The control unit compares predicted torque build-up with actual engine behavior and refines the prediction algorithm accordingly, creating a closed-loop system that improves predictive accuracy over time based on real-world operating conditions.
2Use of energy by moving object
If gear shifts are controlled based on basic limit speed ranges, then automatic shifting can be achieved, but fuel efficiency is compromised due to inaccurate torque build-up prediction
Solution Approach 1:
The patent applies parameter changes by incorporating the thermal state parameters of exhaust system components (particularly turbocharger turbine temperature) into the predictive calculation. Instead of using only standard operating parameters, the system adjusts the prediction model based on thermal parameters that directly affect torque build-up characteristics. This allows the control unit to determine more accurate shift thresholds that optimize fuel efficiency while accounting for the actual physical state of the engine system.
3Measurement precision
If the thermal state of exhaust system components is not considered in predictive calculations, then the control system remains simple, but the accuracy of torque build-up prediction is insufficient
Solution Approach 1:
The patent applies universality by using the existing exhaust system temperature sensors (already present for other purposes such as emissions control and turbocharger protection) for an additional function: improving torque build-up prediction. The control unit repurposes data from these sensors to enhance the shifting strategy, eliminating the need for dedicated temperature measurement systems while still achieving more accurate predictive calculations.
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling a shifting process of an automatic transmission in a vehicle with an internal combustion engine, wherein a shifting strategy is specified in a control unit, in which the behavior of the engine after a possible shift into a target gear is continuously predicted based on currently acquired driving dynamics and/or vehicle-specific and/or engine-specific actual values (6), and, taking these predictive results into account, adapted shift thresholds are determined and specified as upshift thresholds or downshift thresholds, particularly for fuel-efficient shifting, wherein, after a shift threshold is exceeded, a control command for a corresponding automatic shift is issued. According to the invention, the current temperature of at least one component of the engine exhaust system is also taken into account when specifying an adapted shift threshold (7; 9).