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Radiator thermal cycle test is a test method to check out the robustness of a radiator. During the test, the radiator is going through transient cycles that include high and low temperature spikes. These spikes could lead to component failure and transient temperature map is the key to predict high thermal strain and failure locations. In this investigation, an accurate and efficient way of building a numerical model to simulate the transient thermal performance of the radiator is introduced. A good correlation with physical test result is observed on temperature values at various locations.

Automotive thermal systems are of major importance in ensuring optimum operating of thermal engines and in preserving battery capacities. These systems involve various components with a wide range of technologies, designs and subcomponents as HVACs, compressors or fan systems. Currently, as thermal engine noises are reduced and electrification trends are continuously increasing, thermal systems can be a major source of noise and vibration. These NVH issues can emerge inside the car cabin inducing significant discomfort to passengers and can also emerge outside the car causing major disturbances to passersby. During development stages, NVH issues are mastered and contained by suppliers according to internal specifications in addition to complying with OEM requirements. However, NVH issues may not be well detected when using regular NVH metrics.

In order to reduce the cost of engine cooling systems in particular the turbo Diesel engines with charge air coolers, we want to understand the relationship between oil sump temperatures and engine coolant temperatures and their impact on one another. Several cars have been tested in the climatic wind tunnel. The following are the cooling specifications: hill climbing with 12% grade with or without a trailer at a 20°C ambient max. speed at 35°C ambient. The main results of these studies were: a great variation of oil sump temperature versus coolant temperature a small variation of coolant temperature versus oil sump temperature a very small variation of heat flux in the oil, in the coolant and the output of engine versus oil sump and coolant temperature.

The market needs for quieter engine cooling modules and the upcoming stringent noise level regulations have led Valeo to develop a series of numerical codes which will give the fan designer accurate noise predictions and will also ideally complement its CFD simulation based design for its future fan technology [1]. The current approach involves three levels of noise prediction: first a global sound pressure level estimate which will use the fluid 2D CFD blade cascade information; secondly, a spectral distribution which relies on fan loads to provide a first estimate of the subjective noise; finally, a temporal approach based on the Ffowcs-Williams theory which will come the closest to the actual measurements and will fully use the 3D CFD fan data. Validation calculations and first predictions have shown that, even if an accurate absolute noise level cannot always be obtained (within 1 dBA), observed experimental trends are already well captured.

This paper deals with engine evaporative cooling on the VW TDI diesel engine at high heat rejection running points. Engine tests and thermohydraulic 3D computations inside the engine head are used. First, the basic engine is studied. Then, the flow rate corresponding to evaporation is determined. Around this flow rate, the influence of inlet coolant temperature and circuit pressure are studied. The engine tests and 3D calculations give hydraulic ways of improvements consisting in balancing the flows around the different cylinders. Geometrical modifications of the inside engine circuit (gasket....) are then tested to achieve these improvements.

Tests have been conducted to evaluate materials suitable for headers of CAB brazed aluminum radiators, particularly as concerns pressure cycle endurance. These tests were done on different alloy compositions, for both standard and proprietary versions from series 6000 and 3000, with or without post-braze heat treatment. The results from those tests have helped to evaluate the influence of various material characteristics over the pressure cycling resistance. In particular, they have shown that post-braze yield strength was not the only parameter to consider. It appeared also that none of the materials tested could give good results for all designs and test conditions, but, at least, this study has helped to state more precisely what the contents of a specification for an ideal material should be.

The Heating Ventilation and Air Conditioning system (HVAC) is a compact and complex system designed to provide thermal comfort inside the car cabin. The system is composed of various components: fan, flaps, thermal exchangers, filters and specific turned ducts allowing thermal conditioning and airflow distribution to car cabin areas. Nowadays, as thermal engine noises are reduced and electrified car sales are increasing, the HVAC could be a major noise source inside the car cabin that could induce significant discomfort to passengers. HVAC noise issues are well known and solved. Many of them are related to the fans’ electrical motor, such as ticking and harmonic noises. The remaining noises are mainly aeroacoustic linked to the fan and interactions between HVAC components and airflow. HVAC behavior also consists of transfer paths and acoustic transparency responsible of emerging noises.

With the rise of electric autonomous vehicles, it has become clear that the cabin of tomorrow will drastically evolve to both improve ride experience and reduce energy consumption. In addition, autonomy will change the transportation paradigm, leading to a reinvention of the cabin seating layout which will offer the opportunity to climate systems team to design quiet and even more energy efficient systems. Consequently, Heat and Ventilation Air Conditioning (HVAC) systems designers have to deliver products which perform acoustically better than before, but often with less development time. To success under such constraints, designers need access to methods providing both assessment of the system (or subsystems) acoustic performance, and identification of where the designs need to be improved to reduce noise levels. Such methods are often needed before a physical prototype is requested, and thus can only be achieved in a timely manner through digital testing.

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.

During design development phases, automotive components undergo a strict validation process aiming to demonstrate requested levels of performance and durability. In some cases, specific developments encounter a major blocking point : decoupling systems responsible for optimal acoustic performances. On the one hand, damping rubbers need to be soft to comply with noise, vibration & harshness criteria. However, softness would provoke such high amplitudes during vibration endurance tests that components would suffer from failures. On the other hand, stiffer rubbers, designed for durability purposes, would fail to meet noise compliance. The rubber design development goes through a double-faced dilemma : design with acceptable trade-off between NVH and durability, and efficient ways to develop compliant designs. This paper illustrates two case studies where different methodologies are applied to validate decoupling systems from both acoustic and reliability perspectives.