ISG Logic Control for Downhill Slope Stability
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Solution Overview
Problem
Current ISG logic systems fail to ensure stable engine restarts on downhill slopes, leading to potential vehicle movement issues due to inadequate consideration of road inclination, which affects safety and fuel efficiency.
Innovation Solution
A method and device for controlling ISG logic that uses an inclination sensor to determine road inclination, internally controlling the vehicle to a neutral state when downhill, delaying gear shifts, and limiting engine torque to prevent impacts and ensure stable starts, incorporating a brake pedal switch, shift lever switch, inclination sensor, controller, and engine unit to manage hydraulic pressure and engine torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is stopped to improve fuel efficiency using ISG system, then fuel efficiency is improved, but vehicle stability and safety are compromised on downhill slopes
Solution Approach 1:
The system changes the transmission gear state parameter based on road inclination detection. When downhill slope is detected during engine stop, the transmission is automatically shifted to a lower gear (e.g., from D-range to 3rd gear or lower) to utilize engine braking effect, preventing vehicle movement while maintaining fuel efficiency benefits
Solution Approach 2:
The control unit acts as an intermediary between the inclination sensor and the transmission system. It receives inclination data, processes the information, and automatically adjusts transmission gear state without driver intervention, ensuring safety while maintaining ISG functionality
2Ease of operation
If the ISG logic does not consider road inclination, then the system is simple to operate, but unintended vehicle movement occurs on downhill slopes
Solution Approach 1:
The system performs self-adjustment by automatically detecting road inclination through the inclination sensor and autonomously adjusting transmission gear state. The driver simply operates the brake pedal as usual, while the system handles the complex inclination-based logic adjustments without requiring driver knowledge or manual intervention
Solution Approach 2:
The inclination sensor provides continuous feedback to the control unit about road slope conditions. This feedback loop enables the system to dynamically adjust transmission state in real-time based on actual road conditions, preventing unintended movement while maintaining simple operation for the driver
3Device complexity
If the transmission state is not adjusted on downhill slopes, then the system complexity is low, but vehicle safety is compromised during engine restart
Solution Approach 1:
The system performs preliminary adjustment of transmission gear state before engine restart occurs. When downhill inclination is detected during engine stop, the transmission is pre-adjusted to an appropriate lower gear, ensuring the vehicle is in a safe state before the engine restarts, thereby preventing potential safety issues
Solution Approach 2:
The transmission control system becomes dynamic by automatically adjusting gear state based on real-time inclination data. The system transitions from a static fixed-gear approach to a dynamic adaptive approach, where gear state changes automatically according to road conditions, enhancing safety without requiring complex manual intervention
Data Source
AI summary
A device for controlling ISG logic is mounted in a vehicle equipped with an ISG system. The device includes a brake pedal switch, a shift lever switch that shows the current state of a gear of the vehicle, an inclination sensor that is mounted in the vehicle and measures the inclination of a road where the vehicle is positioned, a controller that internally controls the vehicle to an N (Neutral) state, regardless of the gear range shown by the shift lever switch, for the vehicle on a downhill, in accordance with the measured inclination, and an engine unit that performed idle stop when the brake pedal becomes ON, with the gear of the vehicle at a D (Drive) sate, and restarts the stopped engine when the brake pedal becomes OFF, with the gear of the vehicle at the D state.