Dynamic Debouncing Timer for Engine Start-Stop Control
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Solution Overview
Problem
Shift by wire vehicles face challenges in managing engine start and stop cycles due to static debouncing delay timers, which are inadequate for varying transition times and complexities introduced by additional modes like sport mode, leading to unintended engine toggling and inefficient fuel consumption.
Innovation Solution
A dynamic debouncing delay timer is implemented, based on aggregated user data to determine mean mode-specific shift times, considering brake status and mode transitions, with a vehicle information system sending data to a cloud server for calculating average transition periods and updating the start and stop control scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static debouncing delay timer is used for engine start and stop control, then the control logic is simple, but the timer is inadequate for varying transition times and causes unintended engine toggling
Solution Approach 1:
The patent implements a dynamic debouncing delay timer that adapts based on the specific mode transition being performed. Different transition types (e.g., Park to Drive vs. Reverse to Neutral) have different timer durations tailored to their typical completion times. This resolves the contradiction by making the timer reliable for various transitions without requiring an overly complex control system, as the dynamics are managed through pre-defined transition profiles.
Solution Approach 2:
The system changes the timer parameter (debouncing delay duration) based on the detected mode transition type. By monitoring the sequence of modes passed through during a transition, the system selects an appropriate timer duration from a set of predefined values. This allows the control system to adapt to varying transition times while maintaining manageable complexity through parameter adjustment rather than structural complexity.
2Adaptability or versatility
If additional modes like sport mode are added to shift by wire vehicles, then the vehicle performance characteristics are enhanced, but the control logic for engine stops and starts becomes more complex
Solution Approach 1:
The patent segments the control logic by creating distinct transition profiles for different mode change scenarios. Each profile (e.g., Sport mode transitions, Reverse mode transitions) has its own optimized debouncing timer settings. This segmentation allows the system to handle multiple modes and transition types without creating a monolithic complex control logic, as each segment can be independently configured and managed.
Solution Approach 2:
The control system uses a universal debouncing timer mechanism that serves multiple functions across different mode transitions. By making the timer duration adjustable based on the transition type rather than having separate fixed timers for each mode, the system achieves multi-functionality. This universal approach handles Sport mode, Reverse mode, and other transitions through a single adaptable control structure, reducing overall complexity.
3Ease of manufacture
If a static time window is used for debouncing, then the implementation is straightforward, but it is ineffective for varying transition times between different modes
Solution Approach 1:
The system implements a dynamic time window that adjusts its duration based on the specific mode transition being monitored. Instead of a fixed static window, the timer duration is selected from multiple predefined values corresponding to different transition types (e.g., longer windows for Reverse mode, shorter for direct Park to Drive). This maintains ease of implementation through pre-defined profiles while achieving adaptability to varying transition times.
Solution Approach 2:
The time window parameter is changed based on the detected transition sequence. The system monitors which modes are passed through during a shift operation and selects an appropriate timer duration accordingly. This parameter adjustment allows the system to accommodate varying transition times for different modes while keeping the implementation straightforward through a lookup-based approach rather than complex real-time calculations.
Data Source
AI summary
A vehicle includes an engine and a controller. The controller starts the engine in response to a brake status before and during a change in vehicle operating mode achieving predetermined states, and expiration of a timer initiated upon completion of the change and having a duration based upon a learned mean mode-specific shift time window. The change is initiated in response to a request to change vehicle operating mode while the engine is off.