Browse Topic: Valve covers

Items (72)

Anisotropic structural modeling of fiber-reinforced polymers used in engine peripheral components

2023-36-0076

1/8/2024

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 In the automotive industry, many components have been replaced by fiber-reinforced polymers, from finishing parts to structural components that are highly mechanically stressed and often also subjected to high temperatures.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 service. Peripheral engine components such as air, oil and fuel filters, canisters, valve covers and intake manifolds are examples of components that are commonly made of fiber reinforced polymers, but that present relevant thermo-mechanical and vibrational requests. The simulation of the polymer injection process and its coupling to structural modeling is a crucial differential in the development of these products. The consideration of the anisotropy caused by the reinforcing fibers in the polymer has a very relevant impact in terms of stresses and strains, as well as the stiffness of these components. The fiber alignment that defines the anisotropy in the part is obtained from the simulation of the injection process and introduced in the finite element model that will be used for structural evaluation of the component. Aiming to illustrate the relevance of this anisotropic structural modeling approach, which couples the manufacturing process with structural simulation, two case studies are presented: a fuel filter subjected to rupture test comparing numerical and experimental results and the second case is the natural frequency analysis and vibration modes of a valve cover.

Bueno, Estela Mari Ricetti, Higa, Armando, Bazaneli, José Augusto

Experimental Valve Motion Measurement Study for Mid-Range Diesel Engine

2022-01-0629

3/29/2022

The valve train is one of the most important part of engine , and its function is fresh charge inlet and exhaust exit according to order of engine based on intake and exhaust valve [1].The compression relief brake mechanism is one of the integrated brake technologies in Internal Combustion Engines (ICE) which not only reduces engine speed during downhill under overspeed condition by opening of one of the exhaust valves before the power stroke but also helpful to reduce brake pad wear by assisting in vehicle braking. The clearance between exhaust valve and piston during compression relief brake event is important aspect for overall valve train dynamic perspective. Valve motion study included this valve to piston clearance measurement in engine testing as mandate during product development phase. Looking at new products in future and to improve system level valve train dynamics in integrated brake design hardware, it is required to validate the design changes, a valve lift experimental test was performed to understand valve train dynamics during engine running condition. This valve motion measurement study has been performed for the first time for mid-range diesel engines in Cummins Technical Center India (CTCI). The displacement sensors were used for valve lift measurement. Special instrumentation was done on the valve cover to integrate sensor setup. Also, modification was done in exhaust valve spring retainers to incorporate displacement sensors for data acquisition. Steady state measurement data was taken for 50 cycles at various engine operating conditions such as motoring and firing. Peak Cylinder Pressure (PCP) sensor was installed in one cylinder and valve displacement data was acquired in the angle domain. Piston Profile was measured offline with 5-degree resolution in static condition. Upon test completion, all recorded valve displacement data was compared graphically with piston profile to evaluate valve to piston clearances for final validation. Also, there was no contact observed between valve and piston considering compression relief brake event for all Rotation Per Minute (RPM) data captured for firing and motoring conditions. Results are satisfactorily meeting the requirements. Post teardown of engine, all the valves and piston contact regions were found free from any kind of contact marks thereby validating the valve motion study.

Mestry, Kapil, Mahajan, Pratik, Jagadale, Harshavardhini, Bhosale, Sandeep, Gundecha, Deepak, Saha, Siddheswar, Koner, Manas

Blocked Force Determination on Thin Plate Structures Including Applications

2019-01-15256/5/2019

Transfer path analysis is commonly used to determine input forces indirectly utilizing measured responses and transfer functions. Though it is recommended that the source should be detached from the vibrating structure when measuring transfer functions, engineers and technicians frequently have a difficult time in doing so in practice. Recently, a substitute for inverse force determination via transfer path analysis has been suggested. The indirectly determined forces are termed blocked forces and are usable so long as the source and machine are not detached from one another. Blocked forces have the added advantage of being valid even if the machine structure is modified. In this research, a typical automotive engine cover is considered as a receiver structure and is bolted to a plastic source plate excited by an electromagnetic shaker. Blocked forces are determined at different locations, and the correctness of the calculated blocked forces is assessed by comparing the predicted and simulated responses at selected receiver points which were not used for determining the blocked forces.

Chen, Keyu, Herrin, David

International develops new, lighter A26 engine to replace N13

17TOFHP04_10

4/1/2017

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).

Borst, Matthew

Performance Evaluation - Combustion, Emissions and Vibrations-of n-Butanol Binary Mixture with ULSD in an Indirect Injection Engine

2017-01-0875

3/28/2017

This paper investigates the performance of an indirect injection (IDI) diesel engine fueled with Bu25, 75% ultra-low sulfur diesel (ULSD#2) blended with 25% n-butanol by mass. N-butanol, derivable from biomass feedstock, was used given its availability as an alternative fuel that can supplement the existing limited fossil fuel supply. Combustion and emissions were investigated at 2000 rpm across loads of 4.3-7.2 bar indicated mean effective pressure (IMEP). Cylinder pressure was collected using Kistler piezoelectric transducers in the precombustion (PC) and main combustion (MC) chambers. Ignition delays ranged from 0.74 - 1.02 ms for both operated fuels. Even though n-butanol has a lower cetane number, the high swirl in the separate combustion chamber would help advance its premixed combustion. The heat release rate of Bu25 became initially 3 J/crank-angle-degree (CAD) higher than that of ULSD#2 as load increased to 7.2 bar IMEP. Cylinder pressure was 2.25 bar higher within the main chamber for Bu25 compared to the peak values of the ULSD#2 reference. The mechanical efficiency increased with load from 45% to 70% while indicated thermal efficiency reached 44% for 7.2 IMEP load for both fuels. Using an AVL SESAM Fourier Transformed Infrared (FTIR) system and an AVL smoke meter, emissions for the Bu25 fuel blend were measured and showed a decrease of 40% in soot and 2.5% in nitrogen oxides (NOx) at 7.2 bar IMEP. Noise and vibrations measurements were additionally collected using a tri-axial Brüel & Kjær (B&K) accelerometer placed on the valve cover and a B&K multi-field microphone and these were processed in B&K PULSE 19 software. Comparable engine radial vibrations were observed at 7.2 bar IMEP load for both fuels while constant percentage bandwidth (CPB) analysis showcased similar sound levels with a maximum increase of 4 dB at 40 Hz for Bu25. Engine noise and vibrations were not significantly increased at 7.2 bar IMEP during Bu25 operation. The study suggests that n-butanol can be used at 25% as a renewable binary mixture with ULSD#2 while sustaining IDI engine performance.

Soloiu, Valentin, Moncada, Jose, Muinos, Martin, Knowles, Aliyah, Gaubert, Remi, Beyerl, Thomas, Molina, Gustavo

Effects of Oil Formulation, Oil Separator, and Engine Speed and Load on the Particle Size, Chemistry, and Morphology of Diesel Crankcase Aerosols

2016-01-0897

4/5/2016

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 lubricant aerosol is examined on a medium-duty diesel engine operating at different speeds and loads. A unique sampling apparatus is described for sampling the aerosol in the same manner that it enters the intake. In addition, the performance of oil separators is examined. Results demonstrate that the size distribution changes with load, and contains both a sub-micron and super-micron component. The chemical composition of the aerosol varies depending on engine speed and load and oil separator used, while TEM results show that aerosol morphology changes with lubricant viscosity and also engine conditions.

Uy, Dairene, Storey, John, Sluder, C. Scott, Barone, Teresa, Lewis, Sam, Jagner, Mark

Rapid Design and Development of Noise Radiating Engine Components

2014-01-1681

4/1/2014

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 followed by harmonic response studies provides the basis for the iterations towards designing these members. The modal analysis, harmonic response studies and noise radiation efficiency calculations are performed by using a commercial FEA program. It is observed that the suggested Simulation Driven Design and Development approach has reduced the development time from 2 months to 3 weeks for the design finalization.

Shanmugam, Manivasagam, Kharatmal, Raghavendra, Satpute, Shirish

Ship Systems and Equipment - Selection of Hydraulic Directional Control Valves

J1783_201305 (Current)

5/31/2013

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.

Ship Fluid Systems Committee

2012 bike tech takes new twists

12AEID0501_01

5/1/2012

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.

Brooke, Lindsay

Noise Benchmarking of the Detroit Diesel DD15 Engine

2011-01-1566

5/17/2011

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.

Reinhart, Thomas, Smolik, Mitchel

Valve Cover's Numerical Vibro-Acoustic Analysis And Experimetal Correlation

2010-01-1416

6/9/2010

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 conditions; this allows a faster component optimization and, consequently, a reduction of the whole engine system development time, improving it from a NVH point of view. Such methodology had been further validated and developed and is now part of the standard validation plan for new engines.

Armentani, Enrico, De Stefanis, D., Esposito, R., Martorelli, M., Parente, A.

Shedding pounds on a magnesium diet

10AEID0406_04

4/6/2010

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).

Ashley, Steven

For operators, a more quiet day at the office

10OFHD0128_01

1/28/2010

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.”)

Gayman, David

OPTIMIZATION OF THE WALL THICKNESS OF A PLASTIC VALVE COVER

2009-36-007010/6/2009

Recent advances in hardware and software have allowed to development teams to use their time not only solving common CAE analyses but also thinking about the development of CAE optimization environments. Optimization comes like a tool capable to drive design parameters towards regions where selected characteristics of the project can be further improved. This work presents one case that serves to illustrate the application of a optimization technique well known as multi-objective optimization. In the example a Multi-Objective Genetic Algorithm is used to define the thicknesses of several regions over a valve cover looking not only for lower flexibility but also to lower mass. In this case, the commercial code PERMAS was used to verify the structural behavior of the valve cover, as well as to calculate its mass. Design variables were restricted to geometry parameters - cover thickness - while optimization objectives comprised reduction of mass besides of maximization of the cover stiffness aiming to reduce cover leakage. The commercial code modeFRONTIER was used as the process integrator and optimization tool.

Trindade, Wagner Roberto da Silva

Engineering Plastics and Plastic Composites in Automotive Applications

T-1224/3/2009

Before the 1970s, plastics were considered primarily as non-engineering materials and were used in applications such as belts, hoses, gaskets, carpet backing, sealing, adhesives, tires, and so forth as a part of an engineering solution. More recently, plastics have replaced traditional materials and emerged as a significant "engineering application" within the automotive industry. Plastics have proven to be cost effective while providing automakers with the design freedom to accommodate safety, styling, and comfort. Engineering Plastics and Plastic Composites In Automotive Applications focuses on some of the various types of plastics and plastic composites and their applications and advantages within passenger vehicles.

Sehanobish, Kalyan

Chipping away at drivetrain challenges

OFHFEB09_022/1/2009

Chips, sensors, controllers, software all combine to help engineers improve efficiency. Drivetrains are undergoing a significant change as electronic controls manage more operations, helping equipment makers improve operating efficiency. As engineers increase precision with control modules, they are adding more sensors and adopting microcontrollers that have higher speeds and more memory. Many of these changes are being driven by the push to reduce fuel consumption and emissions. But the conversion to electronic controls stretches much further, impacting oil pumps and software while forcing drivetrain engineers to extend their definition of noise to include electromagnetic interference.

Costlow, Terry

The Development of High Efficiency Crankcase Ventilation and Oil Mist Separator for a Heavy-Duty Diesel Application

2008-01-268710/7/2008

Both current exhaust emission legislations and continuously growing customer demand of less oil consumption drive the diesel engine manufacturers to develop more efficient crankcase ventilation and oil mist separation systems. In recent years, integrated design concepts are also considered for almost all sub-systems to achieve compact solutions fulfilling the tightened packaging requirements and more challenging cost targets. This paper presents crankcase ventilation and oil mist separator unit of new generation Ford Otosan Ecotorq Heavy Duty Diesel engines and all work to reach its final configuration, the three-layer filter element with an integrated impactor design. The unit has a compact design as it is integrated to engine valve cover. Challenges brought by the packaging boundary conditions in draining the collected oil by high efficient media are overcome through the extensive experimental development work, which includes tests on special rigs, engines run on dynamometers and fleet tests. Effects of different media types, deflector and impactor designs, oil repellent chemicals and pre-filters are discussed based on the test results.

Gokten, Murat, Kurnaz, Goktan, Ergen, Omer Rustu, Copley, Daniel

Aerospace-Hydraulic Switching Valve, Pressure or Pilot Operated

ARP4741 (Current)

2/7/2008

This SAE Aerospace Recommended Practice (ARP) establishes the requirements for the design, manufacture, and qualification of four hydraulic switching valves used in airborne applications. Two are pressure operated, Type IA and IB and two are solenoid/pilot operated, Type IIA and IIB. They are applicable to four pressure classes 3000, 4000, 5000 and 8000 psi. The equipment as designed is intended to be installed in hydraulic systems designed to AS5440 for military applications or ARP4752 and ARP4925 depending on the type of aircraft for commercial applications. Additional or refined requirements shall be contained in the detail (procurement) specification and these shall take precedence over any potentially conflicting requirements of this ARP or documents referenced by this ARP.

A-6C5 Components Committee

Effects of Seal Viscoelastic Properties on Engine Exterior Cover Noise and Vibration

2007-01-22855/15/2007

Engine exterior cover seals are typically made of elastomeric materials and used to seal the interfaces. The design of engine/transmission seals has been traditionally considered from the sealibility aspects. Recently, there have been additional demands that these seals be designed to reduce the vibration transmitted from engine/transmission and to attenuate the radiated noise. To accomplish this goal, the frequency-dependent viscoelastic properties of the seals will have to be considered. This article examines the frequency-dependent viscoelastic properties of some common elastomeric seals. The impacts of these materials on an engine valve cover noise and vibration are particularly investigated. Some design strategies are also discussed to optimize the viscoelastic effects of the elastomeric seals.

Lu, Y. Charles

Valve, Pressure Equalizing, Gaseous Products

AS27166 (Current)

11/14/2006

This specification covers low pressure equalizing, gaseous product valves for use in shipping containers.

AGE-4 Packaging, Handling and Transportability Committee

Materials for Noise and Vibration Control: What Causes Product Variability?

2006-01-322610/8/2006

Many methods for damping -- attenuating - unwanted noises and vibrations found in vehicles, engineering components, and electronic systems are available. A special type of damping material involves polymer-based coatings whose compositions may be “tuned” to attenuate vibration that may occur over specific temperature ranges. These coatings exhibit both elastic flow and viscous flow, depending on their temperature, and are commonly referred to as viscoelastic materials. Today, viscoelastic materials are used to fabricate many types of engineering components for automotive applications, including engine oil pans, valve covers, dash panels, and shims or insulators for brake noise damping. No matter their application, expected performance for viscoelastic damping materials is based on two factors: (1) the quality of coating-to-substrate interfaces; (2) the quality of the viscoelastic coating itself. Thus, performance is a complex function of the individual materials and processes used in fabricating the damping material, including but not limited to substrate cleaning and pre-treatment, choices of primers, solvent removal, coating composition, proper curing and thicknesses. This paper takes the form of an analysis of potential failure modes of interfaces and coatings in viscoelastic damping materials and reviews their effects on performance. Background information includes comments and data on proper selection of materials, processing parameters, and how damping characteristics can be compared. The oral presentation will emphasize materials and their application to damping vehicle brake noise. This approach will provide a tutorial on the many factors to be considered in managing and reducing variability in quality and performance.

Dickinson, Richard C

CAE approach for Plastic Valve Cover System- Part 2

2006-01-08274/3/2006

The Plastic Valve Cover System (PVCS) should provides a leak proof seal to the cylinder head under engine temperature, isolate the vibrations transmitted from the engine through the cover to the environment, control the crankcase pressure and house the device to separate oil from the blow-by gas. In order to increase the stiffness of PVCS, short glass fibers and minerals are added during the injection molding of the plastic valve cover. The presence of the fibers results in a component with highly anisotropic thermo-mechanical properties that was not accounted in the previously approach [1]. This paper describes the updated CAE approach with the incorporation of the short fiber anisotropy into the design of cylinder head valve covers.

Pereira, Dimitrius C., Schnurrenberger, Joachim, Lu, Y. Charles, Bastías, Pedro, Anderson, Mike, Nation, Keith

Effect of Injector Nozzle Finish on Performance and Emissions in a HSDI, Light-duty, Diesel Engine

2006-01-02004/3/2006

The purpose of this study was to determine the effect of injector nozzle hole size, shape, and finish on performance and emissions in a light-duty diesel engine. Two sets of six-hole valve covered orifice (VCO) nozzles were tested with nearly identical volumetric flow rates but varying geometry and finish. The 17% hydro-erosion (HE) nozzles had a 22% larger discharge coefficient (CD), compared to the 7% HE nozzles. In order to maintain similar volumetric flow rates, the orifice diameter of the 17% HE nozzles were reduced by almost 10%.The nozzles were tested in a 1.7L, four-cylinder, common rail diesel engine, operating on conventional D2 diesel fuel. The 17% HE, conical-shaped nozzles reduced fuel specific particulate matter (PM) and increased fuel specific oxides of nitrogen (NOx) emissions, over the 7% HE, straight-shaped nozzle. In-cylinder visualization showed a consistent trend toward reduced late-cycle soot concentration with the 17% HE nozzles which trended with engine-out soot.

Miers, Scott A., Ciatti, Stephen A.

2006 Engine Special Report

AUTOJAN06_021/1/2006

Our annual review of the most significant internal-combustion engines of the year ranges from a novel forced-induction four cylinder designed for displacement downsizing to a V10 powerhouse focusing on high output, with three V6s in between. The 2GR-FSE is the latest and most powerful member of Toyota's GR-series light-alloy, quad-camshaft, four-valves-per-cylinder, 60-degree bank angle V6 family, and encompasses the company's leading-edge direct-injection gasoline engine technology. The 2GR-FSE is uniquely significant for Toyota and its newly formed (for Japan) Lexus Division, says Project General Manager Shizuo Abe of Engine Design Dept. 1, Engine Engineering Division 1. It propels the new Lexus GS and IS sedans, two of the three launch vehicles of the premier brand in Japan, as well the IS350 for the world market and the soon-to-be-launched GS450h gasoline-electric hybrid.

Finite Element Analysis for a Plastic Valve Cover System with anisotropic thermo-mechanical properties

2005-01-401911/22/2005

In order to increase the stiffness of cylinder head plastic valve cover system (PVCS), short glass fibers and minerals are added during the injection molding of the plastic valve cover. The fibers orient themselves according to the local characteristics of the flow and the geometry of the part. The presence of the fibers results in a component with highly anisotropic thermo-mechanical properties. Traditional finite element analysis methods do not account for this, very important, phenomenon. The present manuscript describes work conducted at Dana Corp. aimed at incorporating short fiber anisotropy into the design of cylinder head valve covers.

Pereira, Dimitrius Caloghero, Bastías, Pedro, Anderson, Mike, Schnurrenberger, Joachim, Felippe, Bruno

A Study of the In-Nozzle Flow Characteristic of Valve Covered Orifice Nozzles for Gasoline Direct Injection

2005-01-368410/24/2005

For spark ignition engines, the most effective way to reduce the overall fuel consumption and CO2 emissions respectively is the implementation of gasoline direct injection technology. In comparison to the current wall and air guided systems, the direct injection system of the second generation - the spray guided DI- is the most promising one with respect to fuel economy and emission. In order to exploit its full potential, a thorough combustion process development regarding injector and spark plug design and their positioning within the combustion chamber is essential. Especially multihole injectors offer many degrees of freedom with regard to the nozzle shape and spray pattern. To reduce the development work and costs necessary to identify the ideal nozzle characteristic and spray pattern, reliable CFD models are necessary. Although many investigations of the in-nozzle flow of real size multihole injectors for diesel applications have been carried out within the last decade, publications of research work using optical gasoline injectors, especially multihole injectors, are very limited. In order to improve and validate the CFD models, a comprehensive understanding of the flow characteristic within gasoline injectors is essential. This paper presents the results of an investigation of the in-nozzle flow characteristic of a Valve Covered Orifice (VCO) type nozzle. A transparent real size single hole injector was developed and adapted to a pressure chamber. A series of experiments for the visualisation of the onset and development of cavitation inside the nozzle and the initial fuel break up process was conducted applying the back light illumination method. The influence of different chamber and injection pressures, as well as different nozzle shapes on the injection process and cavitation development were examined.

Gilles-Birth, Isabell, Bernhardt, Sören, Spicher, Ulrich, Rechs, Manfred

Sound Radiation of Engine Covers With Acoustic Infinite Element Method

2005-01-24495/16/2005

The engine valve cover is known to be major contributor to powertrain noise due to its large surface area and relatively small thickness. Thus, the acoustic analysis of the valve cover has become one of the key steps in the design process. The present paper describes an acoustic infinite element approach to model the sound radiation of the valve cover. The valve cover bolted to the engine block behaves like a vibrating membrane in an acoustic medium of infinite extent. Typically, the effect of the infinite medium is modeled using either the boundary element method (BEM), or by specifying an equivalent boundary impedance on the terminating surface of an acoustic finite element mesh (NRBC). In this paper, a third method is introduced, wherein the boundary impedances are replaced by acoustic infinite elements. The methodology is presented using two different models. In the first model, a cover with a geometrically simple shape is analyzed. Due to the simplicity of the shape, the acoustic infinite elements may be coupled directly to the cover structural finite element model, without the need for an intermediate acoustic finite element domain. The results from this model are consistent with those obtained earlier for the same model using acoustic finite elements and an impedance condition. However, the use of acoustic infinite elements has proven to be significantly more efficient, both in terms of meshing effort and computational cost. Next, a fairly complicated cover assembly is modeled using a combination of acoustic finite and infinite elements. Due to the complex features of the cover, a small volume of acoustic finite elements is constructed so as to encompass the cover, and the infinite element mesh is constructed on the terminating surface of this finite element region. The results from this model have been compared with experimental measurements conducted at various engine operating conditions, and satisfactory correlations have been observed. Moreover, the use of acoustic infinite elements and a simple Python script enables the visualization of acoustic results in the far field. This allows the analyst to mesh the acoustic domain only as much as is required to obtain accurate results, thereby further reducing the cost of the analysis. On the whole, the use of acoustic infinite elements proves to be an accurate and efficient technique for modeling the sound radiation from realistic structures.

Lu, Y. Charles, D'Souza, Karl, Chin, Charlie

Validation of Diesel Fuel Spray and Mixture Formation from Nozzle Internal Flow Calculation

2005-01-20985/11/2005

A series calculation methodology from the injector nozzle internal flow to the in-cylinder fuel spray and mixture formation in a diesel engine was developed. The present method was applied to a valve covered orifice (VCO) nozzle with the recent common rail injector system. The nozzle internal flow calculation using an Eulerian three-fluid model and a cavitation model was performed. The needle valve movement during the injection period was taken into account in this calculation. Inside the nozzle hole, cavitation appears at the nozzle hole inlet edge, and the cavitation region separates into two regions due to a secondary flow in the cross section, and it is distributed to the nozzle exit. Unsteady change of the secondary flow caused by needle movement affects the cavitation distribution in the nozzle hole, and the spread angle of the velocity vector at the nozzle exit. The transient data of spatial distributions of velocity, turbulent kinetic energy, dissipation rate, void fraction rate, etc. at the nozzle exit were extracted. These output data were transferred to the spray calculation, in which a primary break-up model was applied to the Discrete Droplet Model (DDM). The calculation results were compared with the results of the measurement data of spray in a constant volume vessel, and the engine in-cylinder visualization results of high speed and full load operating condition. Predicted spray shape, Sauter mean diameter, penetration, and fuel mixture shape showed good agreement with the experimental data.

Masuda, Ryo, Fuyuto, Takayuki, Nagaoka, Makoto, von Berg, Eberhard, Tatschl, Reinhard

Prediction of Distortion and Residual Stresses in a Magnesium High Pressure Diecasting with Considerations to the Diecasting Process

2005-01-03314/11/2005

Magnesium cold chamber diecastings are steadily making inroads into the automotive industry. Parts that are routinely diecast include instrument panels, valve covers, steering columns, transmission case covers, seat pans, and door frames to name a few. In a bid to take full advantage of weight savings, the majority of the parts are optimized during the design process. This means wall thickness are reduced, and ribs are used to reinforce the part for stiffness. As a part of the design and optimization process, generic load analysis is carried out on the part without taking into account the residual stress developed during the casting process. The iterative process is continued until the design responsible engineer is satisfied with the outcome of the analysis. However, during the diecasting process, variations in the thermal patterns are obtained in the die mainly due to section thickness changes of the part, placement of cooling lines and spray patterns. On ejection from the die, the part will inherit a thermal history, which upon cooling to room temperature in air or in a quenching medium will result in part distortion and development of residual stress. Part warpage, which is a consequence of distortion, results in problems during trimming, machining, and assembly. On the other hand, residual stress beyond certain limits might lead to cracking of the part after production or during service. This paper discusses some of these aspects for a high pressure diecast magnesium automotive part.

Sequeira, Winston, Sikorski, Steve, Andersen, Soren, Barnes, Charles

The Development of a Plastic Valve Cover System using Finite Element Analysis

2004-01-326611/16/2004

This paper presents the development of a Plastic Valve Cover System (PVCS) using Finite Element Analysis (FEA). This approach results in a shorter development period and reduced costs. The numerical methodology is divided into two steps. First, a two-dimensional analysis is of the rubber components (gasket, grommet) determines the load-deflection response and the system equilibrium for the complete range of component tolerances. These curves are utilized in a second step. Applied to a three-dimensional model of the cover, the analysis determines the valve cover optimal design. The paper describes other relevant issues related to PVCS's such as: a) influence of strain damage on elastomeric response. b) element type, size and order selection for optimum modeling. Comparisons with experimental results are presented and the appropriate conclusions are drawn.

Pereira, Dimitrius Caloghero, Anderson, Michael, Bastias, Pedro C., Schnurrenberger, Joachim, Campos, Roseane

Grand ride for Grand Cherokee

AUTONOV04_04

11/1/2004

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.

Carney, Dan

Influence of Nozzle Seat Type on Internal Flow of Convergent Nozzles

2004-01-20106/8/2004

A study of the internal flow in the most used nozzle types in Diesel engines (microSAC and valve covered orifice VCO) was carried out in order to compare injection characteristics and understand the differences between them. To determine these differences, several experimental installations will be used, such as the injection rate test rig, steady flow test rig and spray momentum test rig, to obtain a full hydrodynamic characterization. With the help of the silicone methodology and a microscope, it is possible to determine the needle tip geometry (seat). As the geometrical characterization of the components in both nozzles was known, it was possible to carry out a CFD analysis at several needle lifts and thus observe the behavior of the internal flow in the nozzle seats and be able to compare both nozzles

Payri, R., Gil, A., Plazas, A.H., Giménez, B.

global vehicles Highlights from New York

AUTOJUN04_01

6/1/2004

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.

Carney, Dan

Global Viewpoints North America Body building

AUTOMAY04_045/1/2004

The quest for lighter, quieter, and safer cars and light trucks influences the design and engineering of most vehicle areas-body not excluded. To achieve the ubiquitous goals of less mass and enhanced performance- in addition to other objectives such as improved safety and weight-distribution characteristics-executives and engineers in the vehicle body area must necessarily consider what materials will be best suited to specific applications. And today, there is a smorgasbord of materials from which to choose. “It [material selection] depends on the compelling and sometimes competing objectives that you're trying to address with the vehicle design,” said Mike Donoughe, Vice President, Family Vehicle Product Team, Chrysler Group. “Sometimes you go to aluminum because of its lightweight characteristics, and while the material itself might cost more, the total system cost might actually be beneficial relative to steel.”

Gehm, Ryan

Finite Element Analysis of Modules made of Thermoplastic Materials and Elastomeric Gaskets for Powertrain Applications

2004-01-00113/8/2004

The trends to reduce weight, integrate various functions into modules and reduce costs leads to an increasing use of thermoplastic materials (especially Polyamide 6.6 and Polyamide 6). These materials, combined with elastomeric gaskets (ACM, AEM, FKM, HNBR, VMQ) are increasingly used for cover modules (cam and valve cover modules, oil pan modules), for intake manifold modules and for various other parts in the engine compartment. The main difference of thermoplastic materials (Polyamides) compared to metals and even thermosets are softening effects over the temperature range where they are used in engine applications. This material characteristic makes the prediction of long term sealing behavior of these modules more demanding than with conventional materials. In this paper the results of a long term sealing performance analysis with FEA in a temperature range from room temperature up to 150°C will be presented. The results are correlated to tests conducted on a test rig under similar conditions.

Bendl, Klaus, Klump, Uwe G., Hornig, Roy, Kucinski, Ed, Zschau, Axel

Plastics roll into new territory

AUTODEC03_0412/1/2003

From structural members to Class A surfaces, plastics continue to find increasingly broad application in the automotive industry. No single material proves completely satisfactory for all of the application areas on a vehicle, but plastics are gaining considerable attention as a realistic candidate for locales once considered off-limits. Simple reasons for plastics moving to new application zones highlight the ever-present drive for cost and mass reduction. But the more comprehensive agenda behind application progression underscores the innovative engineering work being done by purveyors of plastics. Quadrant Plastic Composites, considered the world's largest glass-mat thermoplastics (GMT) producer, is preparing to enter the realm of exterior body applications via its newest product offering, SymaLITE. The underlying obstacle to using GMT for Class A surfaces is the inherent waviness “caused by the coarseness of the typical fiber reinforcements used in traditional GMT composites,” said Harri Dittmar, Manager of Market Development - Composites for Quadrant Plastic Composites AG of Switzerland.

Buchholz, Kami

Local-Global Finite-Element Analysis for Cam Cover Noise Reduction

2003-01-17255/5/2003

Valve covers are a primary source of radiated engine noise. In this paper, we discuss an analytical approach that captures the complicated nonlinear response of the cam cover gaskets and grommets without the need for a prohibitively large finite-element model of the cam cover system. We utilize a detailed local analysis of the gasket and grommet components and abstract their isolation characteristics for later use in a global NVH (Noise-Vibration-Harshness) system analysis.

Zubeck, Michael W., Marlow, Randall S.

Acoustic Analysis of Isolated Engine Valve Covers

2003-01-16745/5/2003

The powertrain engine is a major source of vibration and noise in automotive vehicles. Among the powertrain components, the valve cover has been identified as one of the main noise contributors due to its large radiating surface and thin shell-like structure. There has been an increasing demand for rapid assessment of the valve cover noise level in the early product design stages. The present study analyzes the radiated sound pressure level (SPL) of a valve cover assembly using the finite element method (FEM). The analysis is first performed using a fully coupled structural-acoustic approach. In this case the solid structure is directly coupled to the enclosed and surrounding air in a single analysis, and the structural and acoustic fields are solved simultaneously. In the next approach, the analysis is performed in a sequential manner, using a submodeling technique. First, the structural vibration of the cover is analyzed in the absence of the surrounding air. In the next analysis, the structural motion of the cover is used to drive the acoustic motion of the surrounding air. A comparison of the results between these two approaches shows them to be consistent. In addition to mechanically induced noise, the air-flow induced noise is also explored in the present study by applying flow pressure fluctuations in the interior air. The overall sound level is determined by superposition of both air-flow and mechanical excitations. In particular, this paper addresses the structural acoustics of an isolated engine valve cover where elastomer isolators and gaskets are used to isolate the cover through viscous damping. The frequency-dependent damping and dynamic modulus used are based on experimental measurements. The results obtained show that the radiated sound level of an isolated cover is noticeably lower than that of a hard-mount one.

Lu, Y. Charles, D'Souza, Karl

New Modified Dow Polyamide Resins Solving Under-the-Hood Warpage Problems

2002-01-21047/9/2002

Polyamide resins are well established within the automotive industry and are widely used in a range of demanding under-the-hood applications such as valve covers and air intake manifolds. In reality however, the disadvantages of conventional nylon products, such as excessive warpage and poor dimensional stability to name but two, make it increasingly difficult for engineers to produce the ever more complex parts demanded by new engine developments. In this paper we shall introduce a new range of modified Dow Polyamide resins that greatly reduce the above mentioned disadvantages. In comparisons with commercially available nylon 6 and 66 materials we shall illustrate improved warpage behaviour and lower moisture pick-up in combination with excellent chemical resistance to, for example, hot motor oil and ethylene glycol. In summation, examples will be provided to illustrate the improved utility of these new, modified Dow Polyamide resins.

Shields, Nigel, Sabat, Philippe J.

Ship Systems and Equipment—Selection of Hydraulic Directional Control Valves

J1783_200203 (Historical)

3/28/2002

Ship Fluid Systems Committee

On the Use of Spatial Transmissibility to Evaluate the NVH Performance of Engine Cover Assembly

2002-01-04583/4/2002

In the present study, the NVH performance of an engine valve cover assembly is analyzed by the use of “spatial transmissibility (TR)”. It is a measure of the spatial response of the cover relative to the spatial response of the underlying structure to which it is connected. A prototyped engine valve cover assembly is examined. The cover transmissibility is computed through the finite element method and also measured by experimental testing. Various isolation systems have been examined and different cover materials have been investigated, including magnesium and thermosetting plastic. The transmissibility provides a strategy for evaluating the NVH characteristic of engine cover assembly in a much more timely, cost-effective manner, while the product is still in the early conceptual stage.

Lu, Y. Charles, Anderson, Michael E.

Hear the noise, feel the vibe

AUTOAUG01_03

8/1/2001

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.

Buchholz, Kami