Vehicle HVAC Solar Aggressiveness Control Near Cabin Setpoint
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Solution Overview
Problem
Existing HVAC systems in vehicles struggle to accurately control cabin temperature due to solar load, often resulting in unpleasant or unexpected temperature adjustments, especially when the cabin temperature is close to the user-set temperature.
Innovation Solution
A vehicle HVAC system that includes solar sensors to measure solar radiation, temperature sensors to monitor cabin air temperature, and a controller that calculates a radiation temperature based on user-set temperature, feedback temperature, and solar heat load, adjusting the target discharge temperature accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solar offset is applied to adjust discharge temperature, then solar load compensation is improved, but temperature stability deteriorates when cabin temperature is close to user-set temperature
Solution Approach 1:
The system dynamically adjusts the solar offset based on real-time conditions. The solar aggressiveness factor is calculated using current cabin temperature, user-set temperature, and solar radiation intensity, allowing the solar compensation to adapt its magnitude according to the temperature difference and solar conditions, thus preventing abrupt temperature changes when already close to the target temperature
Solution Approach 2:
The patent changes the parameter of solar offset magnitude by introducing a solar aggressiveness factor (KA) that scales the solar offset. This factor is derived from the ratio of temperature difference to solar radiation intensity, effectively modulating the solar compensation parameter to be smaller when temperature difference is small, thereby maintaining temperature stability while still compensating for solar load
2Measurement precision
If solar radiation sensing is added, then solar load measurement precision is improved, but device complexity increases
Solution Approach 1:
The solar sensor serves multiple functions: it measures solar radiation intensity for calculating the solar aggressiveness factor, and its output is integrated into the existing HVAC control system along with temperature sensors and user inputs. This multi-functional use of the solar sensor within the unified control architecture minimizes the incremental complexity while achieving precise solar load measurement
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 system effectively accounts for solar load to maintain a comfortable cabin temperature, reducing abrupt temperature changes and improving user experience by using a solar aggressiveness factor to scale down solar offsets.
Implementation Method 1
one or more solar sensors configured to sense solar radiation on the cabin
Implementation Method 2
one or more temperature sensors configured to sense air within the cabin
Implementation Method 3
determine a radiation temperature corresponding to radiative heat transfer into the cabin
Data Source
AI summary
A vehicle includes a system configured to supply air to a cabin of a vehicle at a target discharge temperature. One or more solar sensors configured to sense a solar radiation on the cabin and one or more temperature sensors configured to sense air within the cabin. A controller is configured to receive a user set temperature, obtain a solar heat load from one or more outputs of the one or more solar sensors, and obtain a feedback temperature from one or more outputs of the one or more temperature sensors. The controller is further configured to determine a radiation temperature corresponding to radiative heat transfer into the cabin, the radiation temperature being a function of the feedback temperature and the solar heat load. The controller may then set the target discharge temperature according to the user set temperature, the feedback temperature, and the radiation temperature.