Brake Booster Vacuum Prediction Using Intake Manifold and Acceleration
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Solution Overview
Problem
The existing methods for controlling the operation of air conditioners in vehicles, which rely on the negative pressure of the intake manifold instead of a brake booster sensor, often result in frequent shutdowns leading to deteriorated cooling performance and braking performance due to inaccurate pressure readings.
Innovation Solution
A system and method that predict the negative pressure of the brake booster by integrating the charging and discharging rates based on the intake manifold pressure and an imitated brake pedal force signal, using a controller to generate an acceleration inflection recognition signal and correct these rates, thereby improving the accuracy of brake booster pressure prediction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the negative pressure of the intake manifold is used to control air conditioner operation, then the cost is reduced by omitting the brake booster sensor, but the cooling performance deteriorates due to frequent shutdowns
Solution Approach 1:
The patent creates a virtual brake booster sensor by copying the function of the actual sensor through software algorithms. The ECU calculates brake booster negative pressure based on intake manifold negative pressure and acceleration information, generating a virtual sensor signal that replaces the need for hardware sensors while achieving accurate pressure detection
Solution Approach 2:
The patent introduces acceleration information as an intermediary parameter to bridge the gap between intake manifold negative pressure and actual brake booster negative pressure. By using acceleration data from the acceleration sensor, the system can more accurately predict brake booster pressure changes, reducing false shutdowns of the air conditioner
2Duration of action of stationary object
If the reference pressure for air conditioner control is lowered, then the frequency of air conditioner shutdown is decreased, but the braking performance deteriorates
Solution Approach 1:
The patent dynamically adjusts the control reference pressure based on real-time acceleration information. Instead of using a fixed reference pressure, the system calculates the reference pressure by combining intake manifold negative pressure with acceleration-based corrections, allowing the control threshold to adapt to different driving conditions and maintain both cooling performance and braking performance
Solution Approach 2:
The patent implements a feedback mechanism where the ECU continuously monitors acceleration information and adjusts the virtual brake booster sensor output accordingly. The acceleration data provides feedback on vehicle motion state, enabling the system to distinguish between pressure changes caused by vehicle acceleration and actual brake booster pressure changes, thereby preventing inappropriate air conditioner shutdowns
Data Source
AI summary
A system for predicting a negative pressure of a brake booster of a vehicle includes: a driving information detector detecting driving information related to driving of the vehicle; and a controller determining a negative pressure of an intake manifold based on a pressure of the intake manifold and an atmospheric pressure which is the driving information and including a booster negative pressure predictor predicting the negative pressure of the brake booster by integrating over time a change rate according to a charging rate and a discharging rate of the negative pressure determined using a negative pressure of the brake booster determined in a previous cycle according to a logic for predicting the negative pressure of the brake booster and the negative pressure of the intake manifold of a current cycle and an imitated brake pedal force signal of the current cycle imitating an acceleration of the vehicle.