Vehicle Deceleration Control Using Two-Stage Engine Brake
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle deceleration control systems face challenges in providing smooth deceleration, especially during vehicle stopping operations, and require driver intervention to maintain safe distances or stop at lines, leading to increased operational burden.
Innovation Solution
A deceleration control device that uses a combination of wheel speed sensors and brake actuator feedback to implement a two-stage deceleration control, initially increasing deceleration at a first rate and then at a lower second rate, assisting the driver by reducing the need for further brake pedal depression as the vehicle approaches a stop line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If engine brake control is implemented by controlling transmission ratio of CVT, then deceleration effect is obtained, but smooth deceleration is difficult to achieve and vehicle stopping control is difficult
Solution Approach 1:
The patent applies dynamics by transitioning from static transmission ratio control to dynamic brake operation amount control. The control device dynamically adjusts the brake operation amount based on real-time vehicle speed and deceleration requirements, enabling smooth and continuous deceleration control throughout the stopping process, including the critical low-speed phase where CVT engine brake control becomes ineffective.
Solution Approach 2:
The patent changes the control parameter from transmission ratio to brake operation amount. By controlling the brake operation amount as a variable parameter that can be continuously adjusted based on vehicle speed and deceleration demand, the system achieves smooth deceleration control that adapts to different driving conditions and vehicle states.
2Productivity
If engine brake is controlled according to vehicle speed following brake release operation, then deceleration control is provided, but driver corrective operation is still required when approaching preceding vehicle or stop line
Solution Approach 1:
The patent implements feedback control by continuously monitoring vehicle speed, deceleration amount, and brake operation amount, then adjusting the brake operation amount in response to actual vehicle behavior. This closed-loop control anticipates driver needs and provides automatic corrective actions, reducing the operational burden on the driver when approaching preceding vehicles or stop lines.
Solution Approach 2:
The control device performs self-service by automatically detecting when additional deceleration is needed and adjusting the brake operation amount without requiring driver intervention. The system monitors its own performance and makes necessary corrections, enabling the vehicle to assist itself in maintaining safe following distances and stopping at appropriate locations.
3Force
If brake operation amount is increased to provide positive deceleration control, then deceleration effectiveness is improved, but driver has to take corrective operation by further depression on brake pedal
Solution Approach 1:
The patent applies preliminary action by proactively increasing the brake operation amount in advance before the driver would need to apply additional brake pressure. The control device predicts future deceleration needs based on current vehicle state and surrounding conditions, applying brake force beforehand to prevent the situation where the driver would need to take corrective action.
Data Source
AI summary
Provided herein is a unit and method to assist the driver with brake operation and to lessen the operation burden. This vehicle deceleration control unit is provided with an engine brake that decelerates the vehicle by putting the vehicle in a state in which the power source is driven from the driven side, and when the driver holds brake operation, the deceleration caused by the engine brake is increased at a first rate. Then, once a predetermined time has elapsed after increasing the deceleration at the rise-up rate, the deceleration is increased from the deceleration at that time further at a second rate that is less than the Rise-up rate. Further, when the driver is increasing or decreasing the brake operation, i.e., does not hold the brake operation, the deceleration due to the engine brake is maintained.