Cruise Control Shift Mapping for Towing Load Gear Selection
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Solution Overview
Problem
During constant speed travel control, if towing is not considered when referencing a shift map, there is a risk of inappropriate gear ratio settings, leading to potential downshifts that would not occur during non-towing and missed upshifts when excess power is present.
Innovation Solution
The vehicle constant speed travel control method adjusts the target accelerator pedal opening based on the presence or absence of towing, ensuring that the gear ratio is set appropriately for the running resistance by referencing different shift lines for towing and non-towing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the target accelerator pedal opening is increased as vehicle speed decreases during constant speed travel control on uphill roads, then driving power is improved, but the operating point passes through a downshift line set farther toward higher vehicle speed side, causing inappropriate downshifts during towing
Solution Approach 1:
The invention changes the parameter of the shift map by selecting different shift lines based on towing conditions. When towing is detected, a shift line set for towing conditions is used instead of the normal shift line, thereby adjusting the gear ratio settings to be appropriate for the increased running resistance during towing.
Solution Approach 2:
The invention makes the shift map dynamic by switching between different shift lines based on the towing state. The control device determines whether towing is occurring and dynamically selects the appropriate shift line, allowing the gear ratio control to adapt to changing running resistance conditions during constant speed travel control.
2Device complexity
If a single shift map is used for both towing and non-towing conditions, then device complexity is reduced, but the gear ratio becomes inappropriate for the running resistance during towing
Solution Approach 1:
The invention changes the parameter of the shift map by selecting different shift lines based on towing conditions. When towing is detected, a shift line set for towing conditions is used instead of the normal shift line, thereby adjusting the gear ratio settings to be appropriate for the increased running resistance during towing.
Solution Approach 2:
The invention segments the shift map into multiple shift lines corresponding to different towing conditions. Instead of using a single unified shift map, the system divides the shift characteristics into separate shift lines that can be selectively applied based on the detected towing state, ensuring appropriate gear ratio control for each condition.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A vehicle constant speed travel control method, in which a target driving power DP_T is calculated based on the difference between a target vehicle speed VSP_T and a vehicle speed VSP; a target accelerator pedal opening APO_T is set based on the target driving power DP_T; a gear shift stage based on a shift map is set in accordance with the target accelerator pedal opening APO_T and the presence or absence of towing (running resistance); and the gear shift stage is more readily set to a low-speed stage (high gear ratio) during towing (as the running resistance increases), wherein the referenced target accelerator pedal opening APO_T is set differently in accordance with the presence or absence of towing (running resistance), and the target accelerator pedal opening APO_T is set to be smaller during towing (as the running resistance increases) with respect to the same target driving power DP_T.