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Technical Paper

Microcellular Polyurethane (MCU) for NVH Solutions

2011-05-17
2011-01-1621
While the microcellular urethane is widely known in the automotive industry for its use in jounce bumpers, its use in Noise Vibration Harshness (NVH) applications is often not as well recognized. Even though there are some NVH parts in the market, rubber still dominates it. The objective of this paper is to demonstrate the material properties of MCU and their relevance for NVH applications in chassis and suspension components. It will also demonstrate the importance of package design to suit the use of the MCU material. This is especially important to not only achieve the best performance but also keep overall cost and weight under control. Several application types will be introduced with general design suggestions. A detailed design guideline for these applications is not part of this paper. Each application has a large variety of parameters to be considered in the design. They need to be selectively applied based on customer performance targets.
Technical Paper

Modeling the Stiffness and Damping Properties of Styrene-Butadiene Rubber

2011-05-17
2011-01-1628
Styrene-Butadiene Rubber (SBR), a copolymer of butadiene and styrene, is widely used in the automotive industry due to its high durability and resistance to abrasion, oils and oxidation. Some of the common applications include tires, vibration isolators, and gaskets, among others. This paper characterizes the dynamic behavior of SBR and discusses the suitability of a visco-elastic model of elastomers, known as the Kelvin model, from a mathematical and physical point of view. An optimization algorithm is used to estimate the parameters of the Kelvin model. The resulting model was shown to produce reasonable approximations of measured dynamic stiffness. The model was also used to calculate the self heating of the elastomer due to energy dissipation by the viscous damping components in the model. Developing such a predictive capability is essential in understanding the dynamic behavior of elastomers considering that their dynamic stiffness can in general depend on temperature.
Journal Article

Hot Judder - An Investigation of the Thermo-Elastic and Thermo-Plastic Effects during Braking

2011-05-17
2011-01-1575
Thermo-elastic and thermo-plastic behaviour takes place with a disc brake during heavy braking and it is this aspect of braking that this paper considers. The work is concerned with working towards developing design advice that provides uniform heating of the disc, and equally important, even dissipation of heat from the disc blade. The material presented emanates from a combination of modeling, on-vehicle testing but mainly laboratory observations and subsequent investigations. The experimental work makes use of a purpose built high speed brake dynamometer which incorporates the full vehicle suspension for controlled simulation of the brake and vehicle operating conditions. Advanced instrumentation allows dynamic measurement of brake pressure fluctuations, disc surface temperature and discrete vibration measurements.
Journal Article

Development of Nano Diamond Polymer Coating on Piston Skirt for Fuel Efficiency

2011-04-12
2011-01-1401
Various polymer-based coatings are applied on piston skirt to reduce friction loss between the piston skirt and cylinder bore which is one of main factors of energy loss in an automotive engine system. These coatings generally consist of polymer binder (PAI) and solid lubricants (graphite or MoS₂) for low friction property. On the other hand, the present study found that PTFE as a solid lubricant and nano diamond as hard particles can be used to improve the low friction and wear resistance simultaneously. In the process of producing coating material, diamond particles pulverized to a nano size tend to agglomerate. To prevent this, silane (silicon coupling agent) treatment was applied. The inorganic functional groups of silane are attached to the nano diamond surface, which keep the diamond particles are apart.
Technical Paper

Development of Compact Continuously Variable Transmission Engine for Motorcycles

2011-08-30
2011-01-2030
The continuously variable transmission (CVT) with a rubber belt used in scooters is also regarded as a potential automatic transmission mechanism for conventional motorcycles. By making this system more compact and building it into the engine, a motorcycle CVT engine has been developed that is about the same size as a manual transmission (MT) engine. During driving with a CVT, heat is generated by friction at the sheaves, and therefore it was necessary to secure a certain length of belt to ensure that external air flows efficiently to the sheaves. However, making the CVT more compact restricted the belt length, which decreased cooling performance and increased the number of bends in the belt, making it difficult to maintain durability. To address this issue, a plastic resin drive belt and newly designed sheaves were adopted, and durability of more than that of a scooter was achieved.
Journal Article

Development of an Electronic Resin Throttle Body

2011-08-30
2011-01-2029
The need to improve fuel consumption by saving the weights of automobile parts is growing from the viewpoint of global warming mitigation. In the case of a throttle body for controlling the air flow volume into an engine, it is important to achieve a high dimensional accuracy of the valve-bore gap in the state of closed valve. In fact, most throttle bodies are made of precision-machined metal. Therefore, resin throttle bodies are drawing attention as a lightweight alternate. However, in comparison with metal throttle bodies, resin throttle bodies have two potential disadvantages that should be solved prior to productization. The first one is greater air leakage in the state of closed valve, and the second one is smaller heat conduction for unfreezing the valve in a frigid climate. We have developed an electronic resin throttle body that has overcome the above-mentioned disadvantages.
Journal Article

Determining Isolator Damping for Minimized Response from Impulse: A Theoretical Approach

2011-09-13
2011-01-2239
Several recent product developments for vibration and motion control have needed passive viscous damping, in addition to traditional elastomer-based hysteretic damping, to be successful in their respective applications. In addition to attenuating steady-state vibration, an important function of these recent product developments is to control motion from impulsive or mechanical shock input. Examples are the cab mounts of off-highway vehicles that need damping in the vertical direction to control cab motion from ground input through the vehicle and some torsionally flexible couplings that need damping to control torque spikes from shift shocks or other transient events. In this work, the theoretical damped impulse response quantities of displacement, velocity, acceleration, force, jerk, yank, and jounce are investigated. This work shows that, for certain response quantities, there is a specific magnitude of damping that minimizes response from impulsive or mechanical shock input.
Technical Paper

Halogen Free Synthetic Elastomer Blend to Meet Properties of Fuel Hose Outer Cover (Return Line) Application

2011-09-13
2011-01-2233
Diesel engine fuel hose return line is considered as a low pressure line and consists of two layers. The inner layer is used to carry the excess fuel, thereby hose material shall have resistance to fuel and its residues. The outer layer is used to protect inner layer from heat, ozone and oil spillage, thereby outer cover material shall have resistance against the heat, ozone and engine oil. Currently NBR PVC, NBR and FKM materials have been used as inner layer materials in diesel engine fuel hose outer cover application, according to service temperature. Halogen contained CSM material has been used for outer cover application and the production of CSM material was withdrawn by one of the major manufacturer recently. Current global challenge is to use environment friendly material in vehicle components to make hazardous free environment. To replace CSM material, which contains Halogen, the available options are CPE, CR, HNBR and AEM materials.
Technical Paper

NVH Development of Lightweight Polymer Engines Oil Pans for Gasoline

2009-05-19
2009-01-2060
The increased demand to reduce cost and weight is forcing engine manufacturers to replace some metal under hood components with high performance polymers. The use of these materials has often been avoided in this type of applications due to concerns around their long-term strength and temperature performance. In particular, the materials of choice for the oil pans in the gasoline engines, at the present time, are aluminum and stamped steel. This paper presents a case study to evaluate the NVH performance of a plastic oil pan designed to replace a stamped steel pan in a gasoline engine. Emphasis is given to the design features and material characteristics that were considered to achieve the required NVH performance.
Technical Paper

Weight Reduction Feasibility of Engine Components Concerning Noise and Vibration Characteristics

2009-05-19
2009-01-2049
We assessed the feasibility of weight reduction concerning noise and vibration characteristics for engine components. Three alternatives were plastic intake manifold, stamped steel oil pan, and no balance shaft. The assessment indices were engine noise level, engine mount bracket vibration, and engine block vibration. Reducing the reciprocating mass and applying design alternatives made the removal of balance shaft feasible. The lightweight plastic intake manifold was beneficial to the engine vibration with a little improvement to the engine noise. The stamped steel oil pan, with optimal structural ribs design and EMS calibration, offered all the benefits of weight, vibration, and noise improvements.
Technical Paper

Process Simulation Integration in Product Design

2009-01-21
2009-26-0089
The effect of processing parameters on the material properties is an important design consideration in plastic part design. The process may cause anisotropic properties due to matrix and fiber orientation, develop internal stresses during cooling, cause thickness variation etc. These effects if not considered in the product design and analysis, may result in premature product failure, reduced safety factor, fit and finish issues or higher costs and weight due to over design. Injection molded long glass polypropylene and blow molded PC/ABS have been used in automotive structural parts requiring to meet stringent static and dynamic loads as per the regulatory legislation. This paper demonstrates the use of injection molding and blow molding process simulation to incorporate the process effect on material and structure properties.
Technical Paper

Advanced Thermoplastic Composites for Automotive Semi-Structural Applications

2009-01-21
2009-26-0086
Composite materials have found applications in the aviation industry because of an appropriate combination of properties - high stiffness, high heat performance and lower specific gravities. The Automotive industry has similar needs, and the application of composites in semi-structural application is a natural next phase. This is also necessitated because of global emphases on fuel efficiency and safety considerations in automotive applications. In this paper, thermoplastic composite material technology solutions and case studies for a number of applications, such as front-end-modules, door modules and instrument panel carriers are presented. Since processing and material modeling of composites is of critical importance in the design process, this paper also describes a new definition of isotropic properties of long glass composites, and perhaps the only way of honestly comparing such materials.
Technical Paper

Eco-Friendly Automotive Plastic Seat Design

2009-01-21
2009-26-0087
The performance and design criteria for seat systems require that the seat be lighter for reduced fuel consumption while still meeting the safety requirements specified by legislation. The safety requirements for seats include headrests, seat back static and dynamic structural performance, seat belt anchorage, luggage retention capability, child seat anchorage and top tether requirements as defined by pertinent regulation. The interior space constraints require that the seat be thinner. The seat design is expected to address the growing concern for environmental friendliness. In addition to these main criteria, various additional features such as adjustable and stow-able design are required for customer delight. All these design objectives should be met within a given cost target. Conventional seating systems include a steel frame, with springs attached to provide support and flexibility to foam cushions. The steel frame is made up of several parts welded together.
Technical Paper

A Rapid Temperature Superposition Method to Determine Creep Behaviour of Thermoplastics for Automotive Electronics Applications

2009-01-21
2009-26-0083
Recent developments in polymer technology have gained automotive industry's attention as a viable alternative for ubiquitous metals. Apart from the design loads envisaged, an automotive part is subjected to multiple environmental loads including variation in ambient temperature. In particular, several automotive electronics applications feature product placements in zones of high temperature (on-engine being the most severe with temperatures exceeding 125°C), which drive the material close to melting points. Exposure to such a harsh environment will have adverse effects on the components (particularly those made of plastics) whose life span is expected to be 20 years. This calls for better characterization of polymers to help predict their behavior during usage. The challenge lies in devising an effective experimental procedure backed with an analytical method to present the material property in a rapidly usable format for technical analysis.
Technical Paper

High Performance Thermoplastic Steering Wheel

2009-01-21
2009-26-0074
Basic concept of automobile steering wheel has been largely unchanged for years. A metal armature (cast Magnesium or Aluminum) is typically used for steering wheel in most of vehicles to provide stiffness and strength with an over-molded polyurethane giving shape and occupant protection. Thermoplastic steering wheel concept has been developed from a unique polycarbonate-based, recyclable thermoplastic. Thermoplastic steering wheel offers stiffness, impact and ductility performance needsed for the global automotive markets. It offers a green solution with mass and cost advantages. It also opens new avenues for design flexibility and styling differentiation. This paper presents thermoplastic steering wheel technology which optimizes the weight, processing complexity and performance.
Journal Article

Effect of Fischer-Tropsch Diesel on Fuel Supply System

2011-08-30
2011-01-1950
This paper investigates the effects of Fischer-Tropsch Diesel (FTD) (a completely a paraffinic fuel) on the fuel supply system in automotive applications. In particular, the effects of Gas to Liquid (GTL) (an FTD synthesized from natural gas) on the elastomer components has been investigated by laboratory scale tests and field trials. In the field trials, GTL was supplied to a commercial vehicle operator and the effect of real running conditions was observed. Also, the laboratory scale testing to simulate the actual condition of usage of a commercial vehicle was conducted under stringent conditions, and a correlation with the field trials was investigated. As a result, no negative effects related to GTL were found.
Technical Paper

Parameters Identification of Constitutive Models of Rubber Bushing

2011-04-12
2011-01-0795
Rubber bushing is used in vehicle suspension systems and plays important roles as connection, mounting, or vibration isolation. To study rubber bushings, one method is to acquire parameters of the constitutive models of rubber from tests of material sample, and to obtain stiffness curves by simulation. Generally, the low-cost uni-axial tension or compression test is used for this method. But parameters from these uni-axial tests are not accurate enough and only part of the properties is represented. To get more accurate parameters, other costly tests and special equipments will be needed. Another method is to directly test stiffness of rubber bushing parts in six loading directions. The stiffness can also be approximated by using empirical formulas with dimensions of bushings. This method simplifies the bushing model and is limited. A new approach is proposed in this paper. First, radial and axial stiffness tests of rubber bushing are conducted and stiffness curves are acquired.
Journal Article

Role of Predictive Engineering in the Design Evolution of a Thermoplastic Fender for a Compact SUV

2011-04-12
2011-01-0768
Automotive fenders is one such example where specialized thermoplastic material Noryl GTX* (blend of Polyphenyleneoxide (PPO) + Polyamide (PA)) has successfully replaced metal by meeting functional requirements. The evolution of a fender design to fulfill these requirements is often obtained through a combination of unique material properties and predictive engineering backed design process that accounts for fender behavior during the various phases of its lifecycle. This paper gives an overview of the collaborative design process between Mitsubishi Motors Corporation and SABIC Innovative Plastics and the role of predictive engineering in the evolution of a thermoplastic fender design of Mitsubishi Motors Corporation's compact SUV RVR fender launched recently. While significant predictive work was done on manufacturing and use stage design aspects, the focus of this paper is the design work related to identifying support configuration during the paint bake cycle.
Technical Paper

Polymer Gear Development to Improve Efficiency and NVH Performance of an Engine Mass Balance System

2011-04-12
2011-01-0405
A joint development program between Metaldyne and Victrex Polymer Solutions was established with the goal of developing a cost effective net shape injection molded gear that provides improvements in NVH (Noise Vibration and Harshness) and operating efficiency over conventional high quality iron gears. A detailed DOE (Design of Experiments) evaluating NVH performance of machined gears was performed in a calibrated NVH test cell. Variables in the DOE included material, gear geometry and backlash variation. The DOE showed the PEEK material gears had different geometric sensitivities, such as helix angle effects, on NVH performance. The results of the DOE were then used to develop an optimal injection molded PEEK polymer gear design. A production quality injection molding gear tool was constructed. Net shape production quality PEEK polymer gears were injection molded and the gears were evaluated in a current production mass balance unit for NVH, mechanical efficiency and durability.
Technical Paper

Thermoplastic Roof Crush Countermeasure Design for Improved Roof Crush Resistant to Meet FMVSS-216

2011-04-12
2011-01-1119
An automobile is designed to meet numerous impact events, including frontal impact, side impact, rear impact, and roll over. Roof crush resistance is a test defined by Federal Motor Vehicle Safety Standard (FMVSS) 216. The intent of this test is to evaluate the strength of the roof and supporting body structure during a vehicle rollover. Steel countermeasures are typically used as structural-reinforcing elements to the body structure to improve the crush strength of a vehicle roof. This paper presents a thermoplastic countermeasure (CM) design as a light-weight solution to replace traditional steel countermeasures. Two concepts are discussed in the paper: an all-plastic countermeasure and a plastic/metal hybrid countermeasure consisting of stamped steel with a thermoplastic reinforcing rib structure. Finite Element (FE) methods using LS-DYNA are used to evaluate the performance of these countermeasure concepts.
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