Vehicle Stop Control System for Stable Engine Cranking
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Solution Overview
Problem
Conventional stop control systems for vehicles wastefully consume power by driving the hydraulic pump even when brake fluid pressure is sufficient, and may fail to prevent vehicle movement during idle stops due to insufficient brake fluid pressure.
Innovation Solution
A stop control system that inhibits the operation of the braking force-increasing device during engine cranking to conserve power and ensures stable engine restart, and activates it only when necessary to maintain adequate braking force, using a combination of cranking time, voltage, and road slope detection to optimize braking force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic pump is driven when restart conditions are satisfied and foot brake is stepped on, then the brake fluid pressure is increased to prevent vehicle movement, but power is wastefully consumed when brake fluid pressure is already sufficient
Solution Approach 1:
The control unit receives brake fluid pressure information from a pressure sensor and uses this feedback to determine whether the hydraulic pump should be driven. When the brake fluid pressure is already above a predetermined threshold, the control unit prohibits driving the hydraulic pump, thereby avoiding wasteful power consumption while ensuring reliable vehicle movement prevention.
Solution Approach 2:
The system dynamically adjusts the operation state of the hydraulic pump based on real-time brake fluid pressure conditions. The control unit switches between prohibiting and permitting pump operation according to whether the pressure meets the required threshold, optimizing power usage while maintaining safety.
2Use of energy by moving object
If the hydraulic pump is not driven when cranking is not failed, then power consumption is reduced, but there is a risk that vehicle movement cannot be prevented if brake fluid pressure is insufficient
Solution Approach 1:
The system continuously monitors brake fluid pressure through a pressure sensor and uses this feedback to make informed decisions about hydraulic pump operation. This ensures the pump is driven only when necessary to maintain adequate braking force, balancing power consumption with safety reliability.
Solution Approach 2:
The brake system self-regulates by using the pressure sensor to automatically determine when the hydraulic pump needs to operate. The control unit independently assesses whether brake fluid pressure is sufficient and adjusts pump operation accordingly, eliminating the need for conservative continuous operation.
3Reliability
If the hydraulic pump is driven during cranking, then brake fluid pressure is increased to prevent vehicle movement, but power available for cranking is insufficient
Solution Approach 1:
The control unit prohibits hydraulic pump operation in advance during the cranking period, before power shortage occurs. This preliminary prohibition ensures that all available power is allocated to cranking the engine, while the system had already ensured adequate brake fluid pressure was maintained before cranking began.
Solution Approach 2:
The system prepares for potential power shortage during cranking by prohibiting hydraulic pump operation beforehand. This prior cushioning measure ensures that even if brake fluid pressure was borderline, the system had already accounted for the power constraints during cranking by preventing pump operation in advance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution stabilizes engine cranking and restart while efficiently managing power consumption and ensuring effective braking force, preventing vehicle movement during idle stops without power-related malfunctions.
Implementation Method 1
cranking means (start motor 6) for cranking the engine 3 using power supplied from a predetermined power source (battery 7 in embodiments)
Implementation Method 2
a braking force-increasing device (hydraulic pump 55, electric brake 20) that is driven by power supplied from the power source, for increasing the braking force of the vehicle V
Data Source
AI summary
A stop control system for a vehicle is provided, which is capable of stably performing cranking for restarting an internal combustion engine and positively preventing the vehicle from moving by properly increasing a braking force of the vehicle, during an idle stop. In the stop control system for a vehicle according to the present invention, the engine 3 is cranked by the starter motor 6 using the power supplied from the battery 7, when restart conditions are satisfied (step 8 in FIG. 5). Further, the stop control system includes a hydraulic pump 55 driven by the power supplied from the battery 7, for increasing the braking force of the vehicle V. During a stop of the vehicle V, it is determined whether or not the braking force of the vehicle V needs to be increased (FIG. 6), and the hydraulic pump 55 is controlled according to a determination result. Further, in a case where it is determined that the braking force of the vehicle V needs to be increased, the operation of the hydraulic pump 55 is inhibited for a predetermined time period during cranking (steps 36, 37, 41 in FIG. 8).