Brake Booster Pressure Prediction Using Virtual Sensor Logic
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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 lead to frequent shutdowns, resulting in 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 air conditioner shutdowns
Solution Approach 1:
The patent creates a virtual brake booster sensor by copying the function of the actual sensor through software algorithms. The controller predicts brake booster negative pressure by integrating charging and discharging rates based on intake manifold pressure and acceleration signals, thereby replicating sensor functionality without physical hardware
Solution Approach 2:
The patent replaces the mechanical/physical brake booster sensor with an electronic prediction system. Instead of using physical pressure sensing, the system uses mathematical models that integrate charging rates (based on intake manifold negative pressure) and discharging rates (based on acceleration inflection signals) to compute predicted brake booster pressure
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 implements feedback control by continuously monitoring acceleration signals and intake manifold pressure, then adjusting the predicted brake booster pressure in real-time. The controller integrates charging and discharging rates dynamically, allowing the system to respond to changing vehicle conditions and maintain accurate pressure prediction
Solution Approach 2:
The patent makes the pressure prediction system dynamic by using real-time acceleration inflection signals to adjust the discharging rate. Instead of using a fixed reference pressure, the system adapts the predicted pressure based on current vehicle acceleration conditions, allowing optimal control thresholds to vary with driving conditions
3Device complexity
If the negative pressure of the intake manifold is used instead of the real booster sensor, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-establishing the relationship between acceleration inflection signals and brake booster pressure discharging rates. The system pre-integrates charging rates based on intake manifold pressure characteristics, allowing accurate pressure prediction to be achieved through computational preparation rather than complex physical sensing
Solution Approach 2:
The patent introduces acceleration inflection signals as an intermediary to bridge the gap between intake manifold pressure and brake booster pressure. The acceleration signal serves as a mediator that helps the controller understand when pressure is being discharged from the brake booster, enabling accurate prediction without direct pressure sensing
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.