Browse Topic: Defoggers
HVAC systems are of critical importance in ensuring passengers’ thermal comfort inside the car cabin as well as safety requirements for defogging functions. These systems involve various components and subcomponents such as blowers, thermal exchangers or actuators, with a wide range of well-known technologies and also new ones on recently introduced innovative products. Currently, within established electrification trends worldwide, the HVAC system is becoming the most important embedded system that can induce major contribution of noise and vibration. These NVH issues can emerge through different transfer paths inside the car cabin possibly causing significant discomfort to passengers. During developments, the NVH issues are mastered and contained by both suppliers according to internal requirements and OEMs according to specifications. However, OEM specifications are mainly defined by overall noise levels and improvements over the years are generally consisting of reducing these
The heating, ventilation and air conditioning system is one of the complex systems installed inside the cabin of an automobile vehicle. Each HVAC discipline has specific design requirements in terms of packaging space, performance targets, etc. Technical specifications such as airflow, noise, air distribution, allowable leakage rate vary as per vehicle segment and interior design accordingly. While maintaining the design parameters of HVAC, design engineers often face challenges related to water leakage, air leakage, water infiltration, etc. Controlling these parameters becomes crucial for customer satisfaction and for safety features. Several studies on seal proof technology have been conducted and continue to be conducted, whether for air-based applications, water-based applications, or any other fluid material.The application of sealing technology is spread almost everywhere, from domestic purposes to industrial applications. Similarly, in automotive HVAC, the application of foam
During thermal performance testing, achieving thermal balance between two fluid mediums of any heat exchanger is critical. Heat balance ratio (HBR) measures the heat transfer imbalance between two sides (source and sink) in a heat exchanger and also helps in ensuring accuracy of test data. There could be many factors which may lead to the imbalance in thermal performance of the sample under testing e.g. sensors accuracy, test operating range, sample orientation, hysteresis in the data acquisition systems etc. Therefore, a testing procedure needs to be established to achieve a better heat balance ratio as low as less than ±5%, which accounts for errors during instrumentation processes, flow losses & manual errors during testing. The current experimental study focuses on a typical coolant aluminium brazed heater core product which is used in automotive applications for passenger cabin heating during the cold climate conditions, windshield demisting and defrosting. In this study, three
The cabin cool down performance is influenced by heat load, AC system components and Air handling components. The air handling components are AC duct, vane and vent. Design of AC duct vane plays a crucial role in the airflow directivity in cabin which enhances the cabin cool down performance. Simulations are carried out by rotating the vanes manually and requires post process for every iteration. It leads to more time consuming and more number of simulations to achieve the target value. Research articles focusing on automation and optimization of vane articulation studies are scanty. Thus, the objective of this work is to execute the vane articulation study with less manual intervention. A parametric approach is developed by integrating ANSA and ANSYS FLUENT tools. With Direct Fit Morphing and DoE study approach from ANSA delivers the surface mesh model for the different vane angle configurations. This surface mesh model is executed in ANSYS FLUENT for volume meshing, case set-up and
It is particularly easy to get tunnel vision as a domain expert, and focus only on the improvements one could provide in their area of expertise. To make matters worse, many Original Equipment Manufacturers (OEMs) are silo-ed by domain of expertise, unconsciously promoting this single mindedness in design. Unfortunately, the successful and profitable development of a vehicle is dependent on the delicate balance of performance across many domains, involving multiple physics and departments. Taking for instance the design of a Heating, Ventilation & Air Conditioning (HVAC) system, the device’s primary function is to control the climate system in vehicle cabins, and more importantly to make sure that critical areas on the windshield can be defrosted in cold weather conditions within regulation time. With the advent of electric and autonomous vehicles, further importance is now also placed on the energy efficiency of the HVAC, and its noise. During the development of the defrost mode of an
This SAE Recommended Practice establishes uniform test procedures and performance requirements for the defrosting system of enclosed cab trucks, buses, and multipurpose vehicles. It is limited to a test that can be conducted on uniform test equipment in commercially available laboratory facilities. For laboratory evaluation of defroster systems, current engineering practice prescribes that an ice coating of known thickness be applied to the windshield and left- and right-hand side windows to provide more uniform and repeatable test restults, even though—under actual conditions—such a coating would necessarily be scraped off before driving. The test condition, therefore, represents a more severe condition than the actual condition, where the defroster system must merely be capable of maintaining a cleared viewing area. Because of the special nature of the operation of most of these vehicles (where vehicles are generally kept in a garage or warmed up before driving), and since defrosting
Numerical simulations are widely used to predict the performance of products in the automotive development process. In particular, ventilation and defrost performances of automotive HVAC system are developed according to design variables and environmental conditions based on CFD (Computational Fluid Dynamics). Recently, as improvement on both computer hardware performance and analysis technology continues, the usage of simulation has been increasing accordingly. However, the cost of software license also increases in such development environments. In this paper, we introduce our CFD program with OpenFOAM, which is the free, open source CFD software, to simulate flow characteristics of ventilation and defrost in automobile. This program includes self-developed GUI similar to commercial CFD code, two-layer realizable κ-ε turbulence model to secure numerical stability, and fluid film model to check the defrost phenomena with time dependence from OpenFOAM libraries
Nowadays development of automotive HVAC is a challenging task wherein thermal comfort and safety are very critical factors to be met. HVAC system is responsible for the demisting and defrosting of the vehicle’s windshield and for creating/maintaining a pleasing environment inside the cabin by controlling airflow, velocity, temperature and purity of air. Fog or ice which forms on the windshield is the main reason for invisibility and leads to major safety issues to the customers while driving. It has been shown that proper clear visibility for the windshield could be obtained with a better flow pattern and uniform flow distribution in the defrost mode of the HVAC system and defrost duct. Defroster performance has received significant attention from OEMs to meet the specific global performance standards of FMVSS103 and SAE J902. Therefore, defroster performance is seriously taken into consideration during the design of HVAC system and defroster duct. The HVAC unit provides hot air to the
In this study, we developed the defrost performance evaluation technology using the multi-objective optimization method based on the CFD. The defrosting is one of the key factors to ensure the drivers’ safety using the forced flow having proper temperature from HVAC during drive. There are many factors affecting the defrost performance, but the configurations of guide-vane and discharge angles in the center DEF(defrosting) duct section which are main design factors of the defrost performance in automotive, so these were set to the design parameters for this study. For the shape-optimization study, the discharge mass flow rate from the HVAC which is transferred to the windshield and the discharge areas in the center defrost duct were set to the response parameters. And then, the standard deviation value of mass flow rate on the selected discharge areas checking the uniformity of discharge flow was set to the objective function to find the optimal design. The results on the windshield
This SAE Recommend Practice establishes for passenger cars, light trucks, and multipurpose vehicles with GVW of 4500 kg (10000 pounds) or less, as defined by EPA, and M1 category vehicles as defined by the European Commission
Car air conditioners operate in all seasons to keep the cabin temperature cool in summer and warm in winter. In summer, for air conditioning systems without humidity sensors, the system cannot maintain a comfortable humidity level because the dehumidification function stops when the compressor stops. However, a system with humidity sensors can maintain a comfortable level because the system operates with on/off switching control of the compressors based on the information of humidity sensors, even when the engine is stopped. In winter, to reduce the heating load, the air conditioning system, in conjunction with the engine, controls defogging of the windshield using humidity sensors in addition to reducing ventilation loss by increasing the recirculation rate. By adding humidity information, the control of humidity in summer and defogging in winter can minimize the operation of compressors and the engine, and lead to improved fuel consumption without loss of comfort. In particular, in
This SAE Recommended Practice provides a test procedure and performance guideline for evaluating passenger vehicle windshield defrosting systems. It is limited to results of tests that can be conducted on uniform test equipment in commercially available laboratory facilities. The current engineering practice prescribes that for laboratory evaluation of defroster systems, a known quantity of water shall be sprayed on the windshield to form an ice coating and then melted by the defroster under specific vehicle operating conditions. The procedure provides uniform and repeatable laboratory test results, even though under actual conditions such a coating would be removed by scraping before driving the vehicle. The performance obtained, therefore, does not directly relate to actual driving conditions, but serves as a laboratory performance indicator for comparing test results within or between systems. This document is intended as a guide toward standard practice but may be subject to
This SAE Recommended Practice, limited to liquid coolant systems, establishes uniform cold weather bus vehicle heating system test procedures for all vehicles designed to transport 10 or more passengers. Required test equipment, facilities, and definitions are included. Defrosting and defogging procedures and requirements are established by SAE J381 which is hereby included by reference
This SAE Recommended Practice establishes for trucks, buses, and multipurpose passenger vehicles with GVW of 4500 kg (10 000 lb) or greater: a Minimum performance requirements for the electric blower motor switch. b Uniform test procedures that include those tests that can be conducted on uniform test equipment by commercially available laboratory facilities
This SAE Recommended Practice establishes uniform test procedures and performance requirements for the defrosting system of enclosed cab trucks, buses, and multipurpose vehicles. It is limited to a test that can be conducted on uniform test equipment in commercially available laboratory facilities. Current engineering practice prescribes that for laboratory evaluation of defroster systems, an ice coating of known thickness be applied to the windshield and left- and right-hand side windows to provide more uniform and repeatable test results, even though under actual conditions such a coating would necessarily be scraped off before driving. The test condition, therefore, represents a more severe condition than the actual condition, where the defroster system must merely be capable of maintaining a cleared viewing area. Because of the special nature of the operation of most of these vehicles (where vehicles are generally warmed up before or garaged in preparation for road operations) and
This SAE Recommended Practice provides a test procedure and performance guideline for evaluating passenger car windshield defrosting systems. It is limited to results of tests that can be conducted on uniform test equipment in commercially available laboratory facilities. The current engineering practice prescribes that for laboratory evaluation of defroster systems, a known quantity of water shall be sprayed on the windshield to form an ice coating and then melted by the defroster under specific vehicle operating conditions. The procedure provides uniform and repeatable laboratory test results, even though under actual conditions such a coating would be removed by scraping before driving the vehicle. The performance obtained, therefore, does not directly relate to actual driving conditions, but serves as a laboratory performance indicator for comparing test results within or between systems. This document is intended as a guide toward standard practice but may be subject to frequent
The scope of this SAE Recommended Practice is to establish uniform test procedures for passenger cars, to determine whether the system is defined as a defroster or defogger, and to establish minimum performance requirements for each system. A defroster for purposes of this practice is a system which will remove moisture and/or frost from the interior surface of the backlight at −18 °C. A defogger is a system which will remove moisture and/or fog from the interior surface of the backlight at 4 °C. The test procedure is intended to simulate actual conditions by utilizing either a cold room with an appropriate device to introduce air flow over the backlight or a sufficiently large wind tunnel with ambient temperature control. The test procedure and the minimum performance requirements are based on currently available engineering data
This SAE Recommended Practice, limited to liquid coolant systems, establishes uniform vehicle heater test procedures. Both laboratory and complete vehicle tests are specified in this document. Required test equipment, facilities, and definitions are included
Microfabricated, silicon-based capacitive actuator/sensor devices have been developed as prototypes of compact, low-power transducers that would be used to detect the presence (and perhaps eventually measure the thickness) of ice on aircraft lift and control surfaces. These transducers would be mounted flush with surfaces, so that they would not perturb airflows. Transducers of this type could also be used in such diverse applications as detecting ice in refrigerators for triggering defrosting cycles and detecting ice on roadways to trigger warning signals for drivers
This SAE Standard establishes uniform test procedures for the defrosting systems of off-road, self-propelled work machines used in construction, general purpose industrial, agricultural, forestry, and specialized mining machinery categories as identified in SAE J1116, JUN86. It includes tests that can be conducted with uniform test equipment in commercially available laboratory facilities, as well as in an appropriate outdoor environment
This SAE Recommended Practice, limited to liquid coolant systems, establishes uniform cold weather bus vehicle heating system test procedures for all vehicles designed to transport 10 or more passengers. Required test equipment, facilities, and definitions are included. Defrosting and defogging procedures and requirements are established by SAE J381 and SAE J382, which are hereby included by reference
This SAE Recommended Practice presents minimum defrosting system performance requirements for trucks, buses, and multipurpose vehicles when tested according to SAE J381. It is the intent that this document will be reviewed and revised to reflect technological progress in vehicle defroster systems
This SAE Recommended Practice provides a test procedure and performance guideline for evaluating passenger car windshield defrosting systems. It is limited to results of tests that can be conducted on uniform test equipment in commercially available laboratory facilities. The current engineering practice prescribes that for laboratory evaluation of defroster systems, a known quantity of water shall be sprayed on the windshield to form an ice coating and then melted by the defroster under specific vehicle operating conditions. The procedure provides uniform and repeatable laboratory test results, even though under actual conditions such a coating would be removed by scraping before driving the vehicle. The performance obtained, therefore, does not directly relate to actual driving conditions, but serves as a laboratory performance indicator for comparing test results within or between systems. This SAE Recommended Practice is intended as a guide toward standard practice but may be
This SAE Recommended Practice provides a defrosting system performance guideline for trucks, buses, and multi-purpose vehicles when tested according to SAE J381 MAY84. It is limited to results of tests that can be conducted in commercially available laboratory facilities. The current engineering practice prescribes that for laboratory evaluation of defroster systems, a known quantity of water shall be sprayed on the windshield to form an ice coating and then melted by the defroster under specific vehicle operating conditions. The procedure described by SAE J381 MAY84 provides uniform and repeatable laboratory test results, even though under actual conditions such a coating would be removed by scraping before driving the vehicle. The performance obtained, therefore, does not directly relate to actual driving conditions, but serves as a laboratory performance indicator for comparing test results within or between systems. This SAE Recommended Practice is intended as a guide toward
This SAE Recommended Practice establishes uniform test procedures for the defrosting systems of enclosed cab trucks, buses, and multipurpose vehicles. It is limited to tests that can be conducted on uniform test equipment in commercially available laboratory facilities. Current engineering practice prescribes that for laboratory evaluation of defroster systems, an ice coating of known thickness be applied to the windshield to provide more uniform and repeatable test results, even though under actual conditions such a coating would necessarily be scraped off before driving. The test condition, therefore, represents a more severe condition than the actual condition, where the defroster system must merely be capable of maintaining a cleared viewing area. Because of the special nature of the operation of most of these vehicles (where vehicles are generally warmed up before or garaged in preparation for road operations) and since defrosting under steady-state, over-the-road operations is
The scope of this SAE Recommended Practice is to establish uniform test procedures for passenger cars, to determine whether the system is defined as a defroster or defogger, and to establish minimum performance requirements for each system. A defroster for purposes of this practice is a system which will remove moisture and/or frost from the interior surface of the backlight at 0°F (−18°C). A defogger is a system which will remove moisture and/or fog from the interior surface of the backlight at 40°F (4°C). The test procedure is intended to simulate actual conditions by utilizing either a cold room with an appropriate device to introduce air flow over the backlight or a sufficiently large wind tunnel with ambient temperature control. The test procedure and the minimum performance requirements are based on currently available engineering data
This SAE Recommended Practice establishes uniform test procedures for the defrosting systems of enclosed cab trucks, buses, and multipurpose vehicles. It is limited to tests that can be conducted on uniform test equipment in commercially available laboratory facilities. Current engineering practice prescribes that for laboratory evaluation of defroster systems an ice coating of known thickness be applied to the windshield to provide more uniform and repeatable test results, even though under actual conditions such a coating would necessarily be scraped off before driving. The test condition, therefore, represents a more severe condition than the actual condition, where the defroster system must merely be capable of maintaining a cleared viewing area. Because of the special nature of the operation of most of these vehicles (where vehicles are generally warmed up before or garaged in preparation for road operations) and since defrosting under steady state, over-the-road operation is the
This SAE Recommended Practice presents minimum de frosting system performance requirements for trucks, buses, and multi purpose vehicles when tested according to SAE J381. It is the intent that this performance standard will be reviewed and revised to reflect technological progress in vehicle defroster systems
This SAE Recommended Practice establishes uniform test procedures for the defrosting systems of enclosed cab trucks, buses, and multipurpose vehicles. It is limited to tests that can be conducted on uniform test equipment in commercially available laboratory facilities. Current engineering practice prescribes that for laboratory evaluation of defroster systems an ice coating of known thickness be applied to the windshield to provide more uniform and repeatable test results, even though under actual conditions such a coating would necessarily be scraped off before driving. The test condition, therefore, represents a more severe condition than the actual condition, where the defroster system must merely be capable of maintaining a cleared viewing area. Because of the special nature of the operation of most of these vehicles (where vehicles are generally warmed up before or garaged in preparation for road operations) and since defrosting under steady state, over-the road operation is the
The scope of this SAE Recommended Practice is to establish uniform test procedures and minimum performance requirements for passenger car windshield defrosting systems. It is limited to tests that can be conducted on uniform test equipment in commercially available laboratory facilities. The test procedures and minimum performance requirements outlined herein reflect the extensive knowledge and experience which automotive engineers have accumulated in development of windshield defrosting practices. Current engineering practice prescribes that for laboratory evaluation of defroster systems an ice coating, rather than frost, be applied to the windshield to provide more uniform and repeatable test results, frost formation of uniform density being the more difficult to accomplish. The time element for ice removal, therefore, is longer than that required to remove frost, which is the prime purpose of the defroster system. In accordance with established policies of the SAE Technical Board
The scope of this SAE Recommended Practice is to establish uniform test procedures and minimum performance requirements for passenger car windshield defrosting systems. It is limited to tests that can be conducted on uniform test equipment in commercially available laboratory facilities. The test procedures and minimum performance requirements outlined herein reflect the extensive knowledge and experience which automotive engineers have accumulated in development of windshield defrosting practices. Current engineering practice prescribes that for laboratory evaluation of defroster systems an ice coating, rather than frost, be applied to the windshield to provide more uniform and repeatable test results, frost formation of uniform density being the more difficult to accomplish. The time element for ice removal, therefore, is longer than that required to remove frost, which is the prime purpose of the defroster system. In accordance with established policies of the SAE Technical Board
The scope of this SAE Recommended Practice is to establish uniform test procedures and minimum performance requirements for sedan passenger car backlight defogging systems. It is limited to tests that can be conducted on uniform test equipment in commercially available laboratory facilities. The test procedures and minimum performance requirements, outlined in this recommended practice, are based on currently available engineering data. It is the intent that all portions of the recommended practice will be periodically reviewed and revised as additional knowledge regarding defogging performance is developed
The scope of this SAE Recommended Practice is to establish uniform test procedures and minimum performance requirements for passenger car windshield defrosting systems. It is limited to tests that can be conducted on uniform test equipment in commercially available laboratory facilities. The test procedures and minimum performance requirements, outlined in this recommended practice, are based on currently available engineering data. It is the intent that all portions of the recommended practice will be periodically reviewed and revised as additional knowledge regarding vehicle defroster performance is developed
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