Vehicle Slide-Down Control During Garage Shift Operations
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Solution Overview
Problem
Existing vehicle control systems inaccurately determine if a vehicle is sliding down when a garage shift operation is performed, leading to unnecessary engine engagement.
Innovation Solution
A control device with a garage shift operation determination unit and a sliding down determination unit that performs different processes to accurately assess sliding conditions, using shift position, motor rotation speed, and acceleration to differentiate between actual sliding and garage shift operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle is determined to slide down by comparing vehicle speed with threshold speed during garage shift operation, then the engine torque can compensate for motor torque shortage, but the vehicle may be mistakenly determined to slide down causing unnecessary engine engagement
Solution Approach 1:
The sliding down determination process is segmented into two distinct paths: a first determination process for normal conditions and a second determination process for garage shift operations. This segmentation allows the system to apply appropriate determination logic based on the operational context, improving accuracy while managing complexity through conditional branching.
Solution Approach 2:
The determination process dynamically adapts based on the detected shift operation state. When a garage shift operation is detected, the system switches from the first determination process to the second determination process, which uses different criteria (comparing current vehicle speed direction with previous direction) to avoid false positives during shift transitions.
2Speed
If the vehicle is determined to slide down using simple speed comparison, then the response time is fast, but the determination accuracy decreases during garage shift operations
Solution Approach 1:
The system dynamically selects the determination method based on operational context. During garage shift operations, it uses the second determination process that compares vehicle speed directions before and after shift to maintain precision. During normal operations, it uses the faster first determination process, thus adapting response speed and precision to match operational requirements.
Solution Approach 2:
The determination criteria are changed based on the operational state. In normal conditions, the system uses threshold speed comparison. During garage shift operations, it changes to comparing the direction of vehicle speed before and after the shift, thereby adapting the measurement parameters to the specific operational context to maintain accuracy.
3Device complexity
If the system always uses the first sliding down determination process, then the control logic is simple, but it cannot accurately distinguish between actual sliding and garage shift operations
Solution Approach 1:
The control logic is segmented into two distinct determination processes that are selected based on the operational context. The first process is used for normal operations, while the second process specifically handles garage shift operations. This segmentation maintains relative simplicity within each process while improving overall reliability through context-appropriate logic selection.
Solution Approach 2:
The shift operation determination unit acts as an intermediary that detects whether a garage shift operation is occurring and routes the sliding down determination to the appropriate process. This intermediary component enables the system to distinguish between actual sliding and shift operations without significantly complicating the overall control architecture.
Data Source
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AI summary
[Object] It is to provide a control device of a vehicle capable of accurately determining the vehicle to slide down even when a garage shift operation is performed. [Solution] An HCU determines whether a garage shift operation of changing a shift position from one of forward and reverse ranges to the other is performed by a driver (step S1). The HCU performs, if the garage shift operation is determined to be performed, a first sliding down determination process of determining whether the vehicle slides down (step S2), otherwise performing a second sliding down determination process of determining whether the vehicle slides down (step S3), which is different from the first sliding down determination process. Upon determining that the vehicle slides down in accordance with the first or second sliding down determination process ("YES" at step S4), the HCU increases driving force of the vehicle (step S5).