Vehicle functional requirements, emission regulations, and thermal limits all have a direct impact on the design of a powertrain cooling airflow system. Given the expected increase in emission-related heat rejection, suppliers and vehicle manufacturers must work together as partners in the design, selection, and packaging of cooling system components. The goal of this two-day course is to introduce engineers and managers to the basic principles of cooling airflow systems for commercial and off-road vehicles.
Hypersonic flight vehicles have potential applications in strategic defence, space missions, and future civilian high-speed transportation systems. However, structural integration has significant challenges due to extreme aero-thermo-mechanical coupled effects. Scramjet-powered air-breathing hypersonic vehicles experience extreme heat loads induced by combustion, shock waves and viscous heat dissipation. An active cooling thermal protection system for scramjet applications has the highest potential for thermal load management, especially for long-duration flights, considering the weight penalty associated with the heavier passive thermal insulation structures. We consider the case of active cooling of scramjet engine structural walls with endothermic hydrocarbon fuel. We have developed a semi-analytical one-dimensional heat transfer model considering a prismatic core single cooling channel segment as a representative volume element (RVE) to analyse larger scale problems.
Airframe section of rockets, missiles and launch vehicles are typically cylindrical in shape. The cylindrical shell is subjected to high axial load and an external pressure during its operation. The design of cylinders subjected to such loads is generally found to be critical in buckling. To minimize the weight of cylinders, it is typically stiffened with rings and stringers on the inner diameter to increase the buckling load factor. Conventionally the buckling load estimated by analytical or numerical means is multiplied by an empirical factor generally called Knockdown factor (kdf) to get the critical buckling load. This factor is considered to account for the variation between theory and experiment and is specified by handbooks or codes. In aerospace industry, NASA SP 8007 is commonly followed and it specifies the kdf as a lower bound fit curve for experimental data .
Based on the basic structure and operation function of engine throttle, according to the actual structure of a throttle, a 3-dimensional simulation of the transient airflow during the rotation of the throttle from the closed position to the fully open position is realized by using CFD together with the moving mesh technology and the user-defined program. The influence of the throttle movement on the airflow process is studied. The velocity field, pressure field, and flow noise field are analyzed at different angles of throttle rotation. The numerical simulation results show that at the beginning period of the throttle rotation, the vortex appears in the flow field behind the throttle, and the drop of the air pressure between the front and back of the throttle is sharp.
In today's market practise & standard mechanism being provided from OEM, tyre changing mechanism is a tedious job, took long time & much higher efforts in Indian trucking industry harsh environments. Heavy commercial vehicles are fitted with spare wheel carrier that has a rope mechanism to load and unload the spare wheel. The mounting of this system is generally on side of frame/ chassis or within the limits of side member. The invention reduces effort and time required to remove spare tyre. The invention brings the spare wheel to a vertical position where it is easy to remove its bolts and remove it from its mountings. Also, this innovative mechanism is well supported by 3 way actuation system (Air Actuated system, Electric motor driven system or Hydraulic cylinder actuated mechanisms), which reduced human efforts and gives benefit to drivers in terms of comfort.
The China Automotive Technology and Research Center (CATARC) has completed two new wind tunnels at its test center in Tianjin, China: an aerodynamic/aeroacoustic wind tunnel (AAWT), and a climatic wind tunnel (CWT). The AAWT incorporates design features to provide both a very low fan power requirement, 3.1 MW at 250 km/hr with a 28 m2 test section, and a very low background noise, 58.2 dB(A) at 150 km/h, putting it amongst the quietest in the automotive world. These features are also combined with high flow quality, a full boundary layer control system and 5-belt rolling road (producing a 5 mm block height boundary layer profile), an automated traversing system, and a complete acoustic measurement system including a 3-sided microphone array. The CWT, located in the same building as the AAWT, has a flexible nozzle to deliver 250 km/h with an 8.25 m2 nozzle, and 130 km/h with a 13.2 m2 nozzle.
Shell-and-tube heat exchangers, commonly referred to as radiators, are the most prevalent type of heat exchanger within the automotive industry. A pivotal goal for automotive designers is to increase their thermal effectiveness while mitigating pressure drop effects and minimizing the associated costs of design and operation. Their design is a lengthy and intricate process involving the manual creation and refinement of computer-aided design (CAD) models coupled with iterative multi-physics simulations. Consequently, there is a pressing demand for an integrated tool that can automate these discrete steps, yielding a significant enhancement in overall design efficiency. This work aims to introduce an innovative automation tool to streamline the design process, spanning from CAD model generation to identifying optimal design configurations. The proposed methodology is applied explicitly to the context of shell-and-tube heat exchangers, showcasing the tool's efficacy.
With the trend of electrification and connectivity, more electrified parts and more integrated chips are being applied. Thus, potential problems based on electro-magnetic could be taking place much easily and the interest on EMC performance has been rising according to the degree of electrification. In this paper, one of the severest system that is cooling fan motor in terms of EMI is analyzed and improvement ways are suggested to each type of cooling fan. Additionally, optimized configuration of improvement method for EMC also has been derived through analysis and study on EMC. Finally, verification and validation are implemented through system and vehicle level.
The research and development of variable valve train concepts increase the DOF of their functionalities. Beginning with discrete switching between two valve timings (Alfa Romeo: “Variatore de Fase”), also the discrete variability of the valve lift (Honda: “VTEC”) was introduced in the 1980s. Increasing the variability to continuous camshaft phasing in the 1990s (Porsche: “VarioCam”) and lift control in the 2000s (BMW: “VALVETRONIC”) an almost fully variable electrohydraulic valve train concept for the intake valves has been introduced (Alfa Romeo: “MultAir”). Regardless of whether in future a fully variable free valve concept will be introduced or not, a quantitative characterization of the variability of valve trains seems to be necessary to compare different valve train designs with each other. More, the operational parameter of electromagnetic (e.g. voltage, current) or electrohydraulic (e.g. hydraulic pressure, switching times) can be characterized with such a quantity.
Characterization of Embedded Debris Particles on Failed Crankshaft Bearings Jianghuai Yang, Qigui Wang, Zhe Li Materials Engineering & Additive Design & Manufacturing, General Motors Co., LLC Crankshaft bearings serve the function of maintaining the lubrication oil films needed to support the crankshaft journals in hydrodynamic regime of rotation. Discontinuous oil films will cause the journal-bearing couple to be in a mixed or boundary friction condition, or even a bearing seizure or a spun bearing. This condition may further force the crankshaft to break and an engine shutdown. Spun bearings have been identified to be the top reason in engine warranty replacement. Excessive investigations have found large, embedded hard debris particles on the bearings are inevitably the culprit of destroying continuity of the oil films.