System and method for controlling compressor of vehicle
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Solution Overview
Problem
Conventional vehicle air conditioner compressor control systems using intake manifold negative pressure lead to frequent A/C cuts, compromising cooling performance and braking performance due to incorrect pressure measurements, resulting in customer complaints and decreased engine power.
Innovation Solution
A system and method that control the compressor by varying A/C duty and torque based on actual engine load, using an engine controller to detect insufficient intake manifold pressure and reduce A/C duty to prevent A/C cuts, thereby maintaining sufficient brake booster pressure without the need for a brake booster sensor, optimizing cooling and braking performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If A/C cut control is activated when intake manifold negative pressure drops below threshold, then braking performance is improved, but cooling performance deteriorates due to frequent A/C cuts
Solution Approach 1:
The system performs preliminary action by detecting insufficient intake manifold negative pressure before it causes brake booster pressure deficiency. The controller predicts potential A/C cut conditions and preemptively adjusts compressor operation to prevent brake pressure from dropping below acceptable levels, thereby maintaining braking performance while avoiding actual A/C cuts.
Solution Approach 2:
The system implements feedback control by continuously monitoring intake manifold negative pressure and brake booster pressure conditions. Based on the detected pressure levels and predicted A/C cut risk, the controller dynamically adjusts compressor duty cycle to maintain both adequate brake pressure and cooling performance, creating a closed-loop control system that balances competing requirements.
2Productivity
If A/C cut entry condition is set to reduce A/C cut frequency, then cooling performance is improved, but braking performance deteriorates due to insufficient brake booster pressure
Solution Approach 1:
The system performs preliminary action by detecting insufficient intake manifold negative pressure before it causes brake booster pressure deficiency. The controller predicts potential A/C cut conditions and preemptively adjusts compressor operation to prevent brake pressure from dropping below acceptable levels, thereby maintaining braking performance while avoiding actual A/C cuts.
Solution Approach 2:
The system implements feedback control by continuously monitoring intake manifold negative pressure and brake booster pressure conditions. Based on the detected pressure levels and predicted A/C cut risk, the controller dynamically adjusts compressor duty cycle to maintain both adequate brake pressure and cooling performance, creating a closed-loop control system that balances competing requirements.
3Reliability
If A/C duty is reduced to prevent A/C cuts, then braking performance is improved, but engine power performance deteriorates due to reduced cooling demand
Solution Approach 1:
The system applies dynamics by implementing variable compressor control based on real-time operating conditions. The compressor duty cycle is dynamically adjusted according to intake manifold negative pressure levels, brake operation status, and predicted A/C cut risk, allowing the system to optimize the balance between braking performance and cooling performance under different driving conditions rather than using fixed control thresholds.
Solution Approach 2:
The system changes parameters by adjusting compressor duty cycle based on detected pressure conditions and predicted A/C cut risk. The controller modifies operational parameters (compressor on/off timing and duration) in response to varying intake manifold negative pressure and brake booster pressure conditions, enabling adaptive control that maintains braking performance while minimizing impact on cooling performance and engine power.
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
The solution reduces A/C cut frequency, improves braking performance, and enhances customer satisfaction by optimizing the trade-off between cooling and braking performance while reducing costs associated with additional sensors.
Implementation Method 1
a compressor that generates pressure through a piston operation of a cylinder utilizing the power of the engine during operation of the air conditioner (A/C)
Implementation Method 2
determines an engine negative pressure of an intake manifold stored in the brake booster at a value obtained by subtracting the engine pressure from the atmospheric pressure detected by the operation information detector
Data Source
AI summary
A system for controlling a compressor may include an engine controller controlling a fuel injection amount corresponding to an engine load and an opening amount of a throttle by reflecting a required torque required for an air conditioner, an operation information detector for detecting operation information according to driving state of the vehicle, a compressor generating pressure through a piston operation of a cylinder utilizing the power of the engine during operation of the air conditioner, and a controller determining an engine negative pressure of an intake manifold stored in the brake booster at a value, and when the negative pressure of intake manifold is below a first threshold value when the brake is operated, the engine enters a negative pressure recovery mode for predicting an insignificant negative pressure drop condition that falls below a second threshold value which is the A/C cut control condition and reduces the A/C duty.