Browse Topic: Valve covers
The evolution of materials technology has provided in recent decades the replacement of the raw material of many parts made of metal by polymers, carbon fibers, ceramics, and composite materials. This process has been driven by the permanent need to reduce weight and costs, which, even after replacing raw materials, still demand permanent improvement and optimization in the sizing process and in the manufacturing process. In the automotive industry, many components have been replaced by fiber-reinforced polymers, from finishing parts to structural components that are highly mechanically stressed and often also subjected to high temperatures. Although they are lighter and have a lower final cost than conventional metallic parts, components made of fiber-reinforced polymers bring great technological challenges to the development project. Within this context, computational modeling is an indispensable ally for obtaining a product capable of meeting the severe conditions required for its
Any time a new engine is announced, it is major news. Pairing a new engine with a new approach to engine development is even bigger news. International Truck recently unveiled its all-new engine for the Class 8 market: the International A26. Along with that came news of an initiative called Project Alpha, which brought together a small team of powertrain engineers dedicated to a new perspective on engine development. “The A26 was designed from the ground up to deliver industry-leading uptime, durability and reliability,” said Darren Gosbee, vice president of advanced engineering. The 12.4-L A26 sources a MAN D26 inline 6-cylinder crankcase from their partnership with the Volkswagen Group and surrounds it with numerous all-new components to optimize four key criteria: uptime, fuel efficiency, weight and NVH (noise, vibration and harshness).
The recirculation of gases from the crankcase and valvetrain can potentially lead to the entrainment of lubricant in the form of aerosols or mists. As boost pressures increase, the blow-by flow through both the crankcase and the valve cover increases. The resulting lubricant can then become part of the intake charge, potentially leading to fouling of intake components such as the intercooler and the turbocharger. The entrained aerosol which can contain the lubricant and soot may or may not have the same composition as the bulk lubricant. The complex aerodynamic processes that lead to entrainment can strip out heavy components or volatilize light components. Similarly, the physical size and numbers of aerosol particles can be dependent upon the lubricant formulation and engine speed and load. For instance, high rpm and load may increase not only the flow of gases but the amount of lubricant aerosol. In this study, the number, size distribution, composition, and morphology of entrained
This paper describes the rapid design and development of thin walled powertrain components which act as external cover for engine subsystem assemblies. Computer Aided Engineering plays a major role in reducing the overall product development lead time. An approach by using ‘Simulation Driven Design and Development’ helps the developers to bring the necessary confidence about the components' required functionality during the design stage itself. During the design stage, typical inputs available for the development of these components are the broad dimensions obtained from the packaging considerations. The designer is required to develop the concepts targeting least noise radiation from component surfaces due to various excitations. Based on cost considerations, the designer can even opt for plastic materials instead of steel. The current paper considers two major noise radiation members namely valve cover and timing gear cover for rapid product development. A conventional modal analysis
This SAE Recommended Practice provides the designer with guidance for the selection of directional control valves for use in the hydraulic systems of surface ships and submersibles. This guidance includes use of standard valves and interfaces, minimum envelopes that should be reserved to permit interchangeability, environmental considerations, and general technical requirements.
American upstart Motus readies a radical V4 sport-tourer, Ducati unleashes its most advanced V-twin, and electronic controls continue to migrate into the bike industry. “This has been a monumental undertaking,” noted Brian Case, Vice President of Design for Motus Motorcycles, a new U.S.-based start-up that is preparing to produce its first bike later this year as a 2013 model. Recent history doesn't exactly favor emergent U.S. motorcycle OEMs, but Case and Motus President Lee Conn believe their product will beat the odds. The Motus MST and MST-R are premium sport-touring machines more akin to European bikes than to cruisers in the Harley-Davidson mode. They're powered by an all-new 1650-cm3 V4 that is fundamentally half of a General Motors LS-7 V8-two overhead valves per cylinder actuated by pushrods, hydraulic lifters, and a single camshaft in the linerless aluminum block. The nickel-silicon-carbide coated bores are set on 4.27-in (108-mm) centers.
Several new or significantly upgraded heavy duty truck engines are being introduced in the North American market. One important aspect of these new or revised engines is their noise characteristics. This paper describes the noise related characteristics of the new DD15 engine, and compares them to other competitive heavy truck engines. DD15 engine features relevant to noise include a rear gear train, isolated oil pan and valve cover, and an amplified high pressure common rail fuel system. The transition between non-amplified and amplified common rail operation is shown to have a significant noise impact, not unlike the transition between pilot injection and single shot injection in some other engines.
This work describes a numerical vibro-acoustic analysis of a gasoline engine's cylinder head of recent development. The analysis was divided in two main steps: definition and correlation of the numerical model by mean of comparison with tests data, and development of a methodology to identify the potentially critical modes for the NVH performance without knowing the real operational boundaries of the sub-system. The vibrational analysis has focused on the definition of a finite element model for reproducing the behaviour of the component, experimentally obtained by accelerometers placed on the top of the cover. The subsequent acoustic analysis has been executed through a boundary element model. The comparison between numerical results and experimental data was very good. Once the models have been validated and vibration and acoustic transmissibility indexes have been defined, system's critical modes have been identified, disregarding the real forces that arise during engine working
Tough CAFE standards are pushing automakers to consider using more lightweight magnesium rather than aluminum, steel, or plastics. For lightweight car structures, magnesium has always been “the other white metal.” Magnesium is often an afterthought for many North American platform engineers, traditionally an alternative that is perhaps considered late in the game to solve problems with ferrous structures that aluminum might not cure. And even aluminum has become a tougher sell with the arrival of modern high-strength boron and dual-phase steels. But mounting pressure to cut vehicle weight to meet stringent federal CAFE (Corporate Average Fuel Economy) standards for 2016 has magnesium firmly back on the engineers' table. With the tough federal mandates looming, even the conservative tastes of platform engineers can now be tempted by the potential 40% weight savings that magnesium can offer over steel (20 to 25% over aluminum, which is one-third heavier than magnesium).
New materials that reduce weight and new strategies that control vibration are finding their way into heavy equipment. The result is a bit more agility and efficiency. Following a path well-worn by their counterparts in aerospace and automotive design, off-highway engineers seem to be readying themselves to replace metal with thermoplastics. A primary reason is to reduce weight, and a key secondary reason is for controlling noise and vibration. With more than a half century of application in aerospace (and nearly as many years in automotive), reinforced and rigid engineering plastics have produced a track record for reducing weight and cost. During the same span, foams and elastomeric polymers have found widespread application in absorbing vibration and noise. (For basic types and applications, see SOHE June/July 2009, p. 32, “Plastics expand their range.”)
Jeep engineers give the 2005 model more on-road comfort, with all the off-road capability. The 2005 Jeep Grand Cherokee follows closely in the tracks of the 1992 Grand Cherokee in its mission to marry off-road competence with smooth, stable highway ride and handling. The original Range Rover was the first to try to combine these often-contradictory traits, but it was Jeep that addressed this challenge for mainstream customers. The company's latest effort is its best yet, with independent front suspension installed to provide the ride and handling suburban customers demand, but configured to preserve Jeep's trademark off-road prowess. “Just as when it first debuted on the market, the 2005 Jeep Grand Cherokee sets the benchmark for off-road capability and continues to do so for on-road refinement,” said Jeff Bell, Vice President, Jeep.
The 2004 New York International Auto Show saw the most world debuts in the event's history, with strong themes in new midsize luxury cars and midsize SUVs. The new Acura RL, Cadillac STS, and Infiniti M45 debuted carrying an array of new technologies. Real-time traffic information for the navigation systems is supplied by XM Satellite Radio for the Acura and Cadillac, and the Cadillac and Infiniti both carry a new Bose DVD-audio 5.1 channel surround-sound system. Acura Prototype RL-As expected, Acura debuted its next-generation RL prototype with V6 power under the hood. The company remains determined to prove that it can supply high-end luxury and exotic cars without eight pistons.
This SAE Recommended Practice provides the designer with guidance for the selection of directional control valves for use in the hydraulic systems of surface ships and submersibles. This guidance includes use of standard valves and interfaces, minimum envelopes that should be reserved to permit interchangeability, environmental considerations, and general technical requirements.
There being no silver bullet for noise and vibration attenuation, suppliers are providing a variety of options for the OEM quest to provide a smooth and quiet ride. In Paul Parent's mind, “NVH really is a science along with being an art.” The President of Vibracoustic North America, an independent, wholly-owned subsidiary of Freudenberg-NOK, made that observation at SAE's Noise & Vibration Conference & Exhibition held recently in Traverse City, MI. The 11th annual event demonstrated that hybrid vehicles are quietly grabbing noise, vibration, and harshness (NVH) attention.
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