Vehicle Air-Conditioning Compressor Torque Control at High Speed
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Solution Overview
Problem
Existing air-conditioning systems for motor vehicles are insufficient at high speeds due to increased ram pressure, which affects blower speed and air flow, leading to inadequate control over interior temperature and air distribution.
Innovation Solution
Incorporating a torque-determining unit that calculates the drive torque required for the compressor based on air temperature, coolant pressure, and compressor speed, allowing for precise control of the compressor stroke and blower operation to maintain optimal air conditioning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blower speed is reduced to counteract increased ram pressure at high speeds, then the air flow control is improved, but the cooling performance deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of blower speed based on real-time measurement of actual air flow volume and temperature differential across the evaporator. The control unit continuously modifies blower speed to maintain optimal cooling performance while compensating for ram pressure effects at different vehicle speeds, transforming a static control system into a dynamic one that adapts to changing operating conditions.
Solution Approach 2:
The system employs feedback control by measuring the actual air flow volume through sensors (temperature sensors before and after the evaporator, and pressure sensors) and using this information to adjust the blower speed. The control unit calculates the temperature differential and air flow volume, then modifies blower operation to maintain desired cooling performance, creating a closed-loop control system that responds to actual system state.
2Temperature
If the compressor stroke is increased to maintain cooling capacity at high speeds, then the cooling performance is improved, but the energy consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of compressor stroke based on real-time measurement of actual refrigerant mass flow rate and cooling demand. The control unit continuously modifies compressor stroke to maintain optimal cooling capacity while minimizing energy consumption, transforming a static compressor control system into a dynamic one that adapts to changing operating conditions and vehicle speeds.
Solution Approach 2:
The system employs feedback control by measuring the actual refrigerant mass flow rate through sensors (pressure sensors in the coolant circuit and temperature sensors) and using this information to adjust the compressor stroke. The control unit calculates the refrigerant mass flow rate and modifies compressor operation to maintain desired cooling capacity, creating a closed-loop control system that responds to actual system state and optimizes energy usage.
3Ease of operation
If manual control inputs are used to adjust temperature setpoint, then the occupant comfort is improved, but the system complexity increases
Solution Approach 1:
The patent implements a control unit that performs multiple functions: it processes manual occupant inputs, measures actual air flow volume and temperature differential, calculates refrigerant mass flow rate, determines optimal blower and compressor settings, and compensates for ram pressure effects. By consolidating these diverse functions into a single multi-functional control unit, the system achieves comprehensive control capability without proportionally increasing overall system complexity.
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 enables improved air conditioning performance at high speeds by accurately determining and adjusting the drive torque, ensuring consistent temperature and air distribution, even under increased ram pressure conditions.
Implementation Method 1
temperature of air, which has flowed past an evaporator integrated into the coolant circuit for evaporating coolant
Implementation Method 2
air, which has flowed past an evaporator integrated into the coolant circuit for evaporating coolant
Implementation Method 3
pressure of the coolant prevailing in the coolant circuit, e.g., directly, in front of the compressor relative to a flow direction of the coolant
Data Source
AI summary
An air-conditioning system for a motor vehicle includes a coolant circuit, through which it is possible to pump coolant with the aid of a compressor, the air-conditioning system having a torque-determining unit for determining a drive torque required for operating the compressor as a function of a temperature of air, which has flowed past an evaporator integrated into the coolant circuit for evaporating coolant, a pressure of the coolant prevailing in the coolant circuit in front of the compressor relative to a flow direction of the coolant or an actuating signal for setting a settable compressor stroke of the compressor.