Browse Topic: Exhaust systems
Recognizing the significant challenges inherent in the analysis of periodic gas flow through reciprocating engines, one can easily appreciate the value of studying the steady flow through cylinder heads, manifolds, and exhaust systems. In these studies, flow benches are the cornerstone of the experimental apparatus needed to validate theoretical results or to perform purely experimental analysis. The Metal-Mechanics Department of IFSC owns a SuperFlow model SF-110 flow bench that has suffered some in house maintenance and received electronic sensors to allow computerized data acquisition. As the essential original sensors in this flow bench were liquid column manometer (for pressure difference across the test subject) and micromanometer (for pressure difference across the orifice plate used to measure the flow), the essential new sensors are electronic differential pressure sensors (installed in parallel with the original ones). In recent decades, however, the use of a mass air flow
Modal performance of a vehicle body often influences tactile vibrations felt by passengers as well as their acoustic comfort inside the cabin at low frequencies. This paper focuses on a premium hatchback’s development program where a design-intent initial batch of proto-cars were found to meet their targeted NVH performance. However, tactile vibrations in pre-production pilot batch vehicles were found to be of higher intensity. As a resolution, a method of cascading full vehicle level performance to its Body-In-White (BIW) component level was used to understand dynamic behavior of the vehicle and subsequently, to improve structural weakness of the body to achieve the targeted NVH performance. The cascaded modal performance indicated that global bending stiffness of the pre-production bodies was on the lower side w.r.t. that of the design intent body. To identify the root cause, design sensitivity of number and footprint of weld spots, roof bows’ and headers’ attachment stiffness to BIW
ABSTRACT Curtiss-Wright has developed an advanced Smart Power Architecture for Intelligent Power Distribution, based on our Intelligent Power Distribution Demonstration (iPDD) and experience in providing power distribution components specifically for Heavy Brigade Combat Team (HBCT) vehicles. The challenges of power distribution and management in ground vehicles are presented, including issues of scalability, warfighter burden, and the complexity of distributing multiple vehicle power sources. The fundamental building blocks of Smart Power are described, including Power Distribution Units, Power Conditioning Units, and types of Power Conversion Units (AC/DC, DC/DC, DC/AC). A Smart Power Reference Architecture will be presented, showing how it enables scalable and modular power distribution systems. How modular Smart Power Architecture can enable commonality across vehicles and applications. How it can provide automatic and programmable load management, including startup and shutdown
Exhaust gas recirculation technology is one of the main methods to reduce engine emissions. The pressure of the intake pipe of turbocharged direct-injection diesel engine is high, and it is difficult to realize EGR technology. The application of Venturi tube can easily solve this problem. In this paper, the working principle of guide-injection Venturi tube is introduced, the EGR system and structure of a turbocharged diesel engine using the guide-injection Venturi tube are studied. According to the working principle of EGR system of turbocharged diesel engine, the model of guide-injection Venturi tube is established, the calculation grid is divided, and it is carried out by using Computational Fluid Dynamics method that the three-dimensional numerical simulation of the internal flow of Venturi tube under different EGR rates injection. The flow field state, velocity field, pressure field and exhaust gas concentration parameters of the mixture formed by air and EGR exhaust gas in Venturi
The increasing importance of minimizing drag and the absence of an exhaust system result in battery electric vehicles (BEVs) commonly having a very streamlined underbody. Although this shape of underbody is typically characterized by a low acoustic interference potential, significant flow resonance can be observed for certain vehicle configurations and frequencies below 30 Hz. Since the interior of the vehicle can be excited as a Helmholtz resonator, these low-frequency fluctuations result in reduced comfort for the passengers. As preliminary studies have shown, the flow around the front wheel spoilers significantly influences this flow phenomenon. Flow separation occurs at the front-wheel spoilers and at the front wheels. This leads to the generation of vortices which are growing significantly while being transported downstream with the flow. Even small geometric changes to add-on components on the underbody significantly influence both aerodynamics and aeroacoustics. Thus, the goal
Spark ignition engines utilize catalytic converters to reform harmful exhaust gas emissions such as carbon monoxide, unburned hydrocarbons, and oxides of nitrogen into less harmful products. Aftertreatment devices require the use of expensive catalytic metals such as platinum, palladium, and rhodium. Meanwhile, tightening automotive emissions regulations globally necessitate the development of high-performance exhaust gas catalysts. So, automotive manufactures must balance maximizing catalyst performance while minimizing production costs. There are thousands of different recipes for catalytic converters, with each having a different effect on the various catalytic chemical reactions which impact the resultant tailpipe gas composition. In the development of catalytic converters, simulation models are often used to reduce the need for physical parts and testing, thus saving significant time and money. However, calibration of these models can be challenging and requires significant time
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