Search Results

A large portion of the noise transmitted from an engine is a result of structural born vibration which may be radiated through the various pans and covers of the engine if they are not isolated from the engine through the gasketed bolted joints. This paper presents an analytical approach for the design of gasketed bolted joints when vibration isolation is required. A simulation of the scaling and isolation performance was created to include the effects of design, temperature, material properties, and loading conditions on the functionality of the noise isolation/sealing system. A systematic design process is developed and applied to the development of an oil pan gasket/noise isolation system.

Automotive cylinder head gaskets today must not only ensure a dry joint, they must also assist in minimizing cylinder bore and cam journal distortion, decrease crevice volume to help meet stringent emissions requirements, and have the durability to perform well over extended warranty periods. In order to accomplish these varied goals, Multi-Layer Steel gaskets are proving to be the design of choice in an increasing number of automotive cylinder head gasket applications. This paper will discuss how and why a specific design methodology for multi-layer steel cylinder head gaskets successfully addresses today's engine manufacturers' requirements and shows additional promise for the future.

Gaskets using advanced gasket composites (AGC) have been developed for automotive applications which show considerable promise in improving gasket performance (sealing characteristics) at low clamping forces. AGC as a gasket material shows excellent performance under automotive environments. It compares well with a Kevlar fiber paper material. AGC gaskets for water outlet and water pump applications have performed better than the existing gaskets on fixtures and in field. This technology offers several other attractive features such as low scrap, recyclable material, flexibility in design, consistent quality, easily moldable features and messages, etc., some of which may be particularly advantageous to the aftermarket applications..

A test system is presented that performs gas sealability tests on gasket materials and components. The system is computer controlled and capable of providing elevated compressive loads and gas pressures. It incorporates a personal computer controller interface, a hydraulic load frame, and integrated gas pressure control. Gas leakage is measured using a mass flowmeter. It performs several multiple-condition tests, the most important being a load sequence sealability test at constant gas pressure and a pressure and load sequence sealability test. The test system provides for automatic test control and data acquisition, so that the test sequences can run unattended. An overview of sealability test methods is included to provide perspective regarding this development.

The trend in the diesel engine industry is toward longer service life and higher reliability. This trend is accompanied by increased power ratings, stringent emissions standards, and improved fuel efficiency. Consequently, the functional requirements of cylinder head gaskets are often beyond the performance capabilities of traditional gasket materials (nonasbestos paper, graphite, etc.). An engineering effort focused on the functional sealing requirements of current production and future diesel engines, resulted in the development of Edge Molded Metal Plate (EMMP) Cylinder Head Gaskets. This paper examines the design and material considerations and concludes with the primary reasons for selecting EMMP gaskets.

A bolted joint mathematical model is presented which includes flange bending effects. The approach simulates the behavior of a system of elastic flanges, a one component non-linear gasket, and linear elastic bolts subjected to assembly and pressurization loadings. Flange distortion is introduced to the joint diagram to predict the overall, midspan, and under the bolt gasket loads.

An embossed single layer of rubber coated metal is a technology that is being applied to the sealing of gasketed joints in internal combustion engines. This technology has the stability of steel, the sealability of rubber, and the control of stiffness through emboss geometry. The sealing performance of this technology is a function of many parameters involving material properties, gasket geometry, surface finish, and joint loading. The relationship between coolant sealability and these parameters was measured. In this paper, results are presented for half emboss configurations where emboss height, surface finish, and clamp load are varied. The data shows that emboss height and flange surface roughness have little effect on the sealing performance of the material studied. The data can be used to select gasket designs which require less expensive flange finishes and lower assembly loads while providing good sealing performance.

Modern, metal-based, static seal technologies are more sensitive to component flange surface finish effects than their softer, composite cousins. Non-averaging or skidless profilometer instruments are capable of accurately resolving the short-wavelength roughness and long-wavelength waviness components of a surface profile. Simple roughness measurements of a surface often ignore the important waviness features that can result in sealing difficulties with these seal technologies. This paper presents techniques for proper surface profile filtering and investigates the impact of waviness conditions on basic, static sealing performance.