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Solution Notes

High-Speed Inspection: Maintain Cycle Time, Ensure Fastener Quality

2017-06-26
SN-0002
High-Speed Inspection: Maintain Cycle Time, Ensure Fastener Quality is a Solution Notes covering the possibility to inspect all fasteners without affecting installation times by applying a process to automatically measure fasteners while they move through a feed tube into the installation machine. Solution Notes are short, informative pieces covering dynamic and emerging technologies within the aerospace and automotive industries to keep you up to date on how new, applied technologies are being used within the mobility space.
Technical Paper

Testing Elastomers - Can Correlation Be Achieved Between Machines, Load Cells, Fixtures and Operators?

2001-04-30
2001-01-1443
At present, testing elastomeric parts is performed at a level dictated by the users of the testing equipment. No society or testing group has defined a formal standard of testing or a way to calibrate a testing machine. This is in part due to the difficulty involved with testing a material whose properties are in a constant state of flux. To further complicate this issue, testing equipment, testing procedures, fixtures, and a host of other variables including the operators themselves, all can have an impact on the characterization of elastomers. The work presented in this paper looks at identifying some of the variables of testing between machines, load cells, fixtures and operators. It also shows that correlation can be achieved and should be performed between companies to ensure data integrity.
Technical Paper

Experimental Modal Analysis for Cylinder Block-Crankshaft Substructure Systems of Six-cylinder In-line Diesel Engines

2001-04-30
2001-01-1421
A newly developed OHC (Over-Head Camshaft) prototype of a six-cylinder in-line diesel engine (with bore size: 114mm, stroke size: 130mm) was studied, comparing with the previous version of OHV (Over-Head Valve) type engine (with bore size: 110mm, stroke size: 130mm). It was found that the new type of cylinder block (with 130.8 kg of mass) has significantly lower natural frequencies than those for the previous type of cylinder block (with 133.2 kg of mass). Furthermore, slightly more predominant engine noise and vibration were induced in the new engine. The vibration behavior and the excitation force transmission characteristics were investigated by EMA (Experimental Modal Analysis). We performed a series of impact tests for (1) free-free cylinder block, (2) free-free crankshaft substructure with torsional damper and flywheel attached, and (3) the case where (1) and (2) are assembled together.
Technical Paper

Prediction Technique for Vibration of Power-Plant with Elastic Crankshaft System

2001-04-30
2001-01-1420
The dynamic behaviors of power-plant have much effect on interior noises and vibrations of passenger cars, especially, in the frequency range below 1000 Hz. So it is very important to estimate the vibrations of power-plant at the design stage. To predict the dynamic behaviors of power-plant including the rotating elastic crankshaft system, the time domain dynamic simulation methods have been applied, however such analyses require much time and resource of computer. In this report, the exciting forces to the cylinder block are derived in the frequency domain from both the dynamic stiffness of bearing oil films and the dynamic displacements of crankshaft journals, so that the computation time is reduced considerably. To estimate the displacements of the crankshaft journals, the vibrations of an engine crankshaft system including crank journal oil films under firing conditions are calculated using the dynamic stiffness matrix method in the frequency domain.
Technical Paper

Power Steering Pump with Enhanced Cold Start Priming

2001-04-30
2001-01-1422
The objective of the present work was to improve the cold start NVH performance of an automotive power steering pump under low temperature conditions. This objective was accomplished through the use experimental study and measurement. The satisfactory operation of a fixed displacement vane pump in cold temperatures depends on a number of factors including; (1) filling characteristics, (2) the inlet conditions to the pump, (3) the fluid, and (4) the ability of the vanes to maintain contact with the cam surface. In this investigation, factor (4) was chosen for investigation. A unique outlet orifice was designed and tested at three different operating ambient temperatures, -19 °C, -29 °C, and -40 °C. Maximum “noise” duration was measured as the maximum duration of fluid borne pump outlet pressure oscillations greater the 345 kPa peak-to-peak. The results show that noise duration can reduced by as much as 50% at -40 °C.
Technical Paper

Flow Noise Reduction upon Quick Opening the Throttle

2001-04-30
2001-01-1429
With the advance in modularization of engine parts in recent years, there is increased use of plastic-made products in air intake systems. Plastic-made intake manifolds (Fig. 1) provide many advantages including reduced weight, reduced cost, and lower intake air temperatures. However, these manifolds have one disadvantage when compared with conventional aluminum-made intake manifolds, in that they transmit more noise because of their lower material density. For example, plastic intake manifolds of early development often generate flow noise when the throttle is opened quickly. With conventional aluminum intake manifolds, this flow noise had generated, but was not heard. This flow noise is presumed to be generated because of high-speed airflow generated when the throttle is opened quickly, but the mechanism of this noise generation has not been clarified.
Technical Paper

Intake-Valve Temperature Histories During S.I. Engine Warm-Up

2001-05-14
2001-01-1704
The present study is an experimental investigation on the influence of engine operational parameters on the temperature history of intake valves. During the initial stage of the warm-up process, the temperature history of the intake valve followed an exponential behavior with a time constant that ranged from about 23 to 39 s for the test conditions examined. In contrast, the temperature history of the coolant varied linearly with time suggesting that the net heat input to the coolant is roughly constant during the initial stage of the engine warm-up process. After the initial transient phase that lasted about one minute, the temperature rise of the intake valve was quasi-steady. During this latter period, the measured intake valve temperature was predicted by the steady-state temperature correlation developed in an earlier study.
Technical Paper

Optimization Elements for Externally Controlled Air Conditioning Systems

2001-05-14
2001-01-1733
In order to reduce the fuel overconsumption, new air conditioning systems fitted with externally controlled compressors have been implemented. Their operating principle consists in driving electrically (external control) the compressor displacement in order to adjust the cooling capacity delivered by the A/C system to the cooling capacity required by the passenger compartment. Therefore, it is possible to reduce the mechanical power absorbed by the compressor and by this means, the fuel overconsumption. However, this potential of fuel consumption reduction can be only achieved under the condition that the other components of the A/C system, such as the thermostatic expansion valve (TxV), are well adapted all together in order to fully take advantage of the implementation of such new type of compressors. The paper describes the different possibilities of optimization of the TxV in regard to hunting phenomena.
Technical Paper

Model Based Analysis of Compressor Valve Leakage and its Effects on the Efficiency of the Motor-Compressor

2001-05-14
2001-01-1723
In the development of algorithms to detect and diagnose component malfunctions impacting system performance and efficiency, engineers are often faced with the following questions: what is the relevant information required, what sensor or set of sensors is needed to provide this information, how should the information from the sensor signals be extracted, which sensor provides the earliest signal of system efficiency deterioration, and how do these signals change as the severity of the fault increases? A typical approach used to answer these questions is to experiment empirically with the actual system; however, this approach can be expensive and time consuming because it involves a variety of complex instrumentation and requires a fair amount of time to run the tests and analyze the data. An alternate approach, which is considerably less expensive is to use a model of the system and run computer simulations to get insight and understanding into its behavior.
Technical Paper

Application of Mathematical Models to Detect and Diagnose Reciprocating Compressor Valve Leakage

2001-05-14
2001-01-1724
This report presents results from the model simulation of the pressure, vibration, and current signatures as derived in the accompanying publication [1] and compares the simulated data with measured data from an actual laboratory motor-compressor system. The simulations from the models were used to determine the information content of the sensor signals, compare the various diagnostic techniques and develop a multisensor approach based on the integration of these techniques to detect and diagnose reciprocating compressor valve leakage.
Technical Paper

Instabilities Occurring in an Automotive A/C Loop Equipped with an Externally Controlled Compressor and a Thermal Expansion Valve

2001-05-14
2001-01-1717
The new compressor generation, called externally controlled compressors, is able to be electronically driven from zero to its maximum displacement. The cooling power can be adjusted to the exact need and this way the fuel consumption of the automotive A/C loop can be reduced. Unfortunately, for the mean and low thermal loads on the evaporator, this new opportunity is limited by A/C loop operation instabilities. Thanks to an automatic approach of the coupling TxV - Evaporator, we can explain the origin of these instabilities and we can show the involvement of this new compressor generation. Then we propose different improvements such as: a better account of the automatic parameters of the TxV and the evaporator (gains, time constants). a TxV setting modification. a new generation of TxV with a leakage. These solutions are discussed according to their interest.
Technical Paper

The Impact of Metal-free Solar Reflective Film on Vehicle Climate Control

2001-05-14
2001-01-1721
The air-conditioning system can significantly impact the fuel economy and tailpipe emissions of automobiles. If the peak soak temperature of the passenger compartment can be reduced, the air-conditioner compressor can potentially be downsized while maintaining human thermal comfort. Solar reflective film is one way to reduce the peak soak temperature by reducing the solar heat gain into the passenger compartment. A 3M non-metallic solar reflective film (SRF) was tested in two minivans and two sport utility vehicles (SUV). The peak soak temperature was reduced resulting in a quicker cooldown. Using these data, a reduction in air-conditioner size was estimated and the fuel economy and tailpipe emissions were predicted.
Technical Paper

Determining Source Fluidborne Noise Characteristics of Automotive Fluid Power Pumps

2001-04-30
2001-01-1612
A new method, the “3 Pressures/ 2 Systems” method, is developed for determining source flow ripple and internal impedance of fluid power pumps. The method integrates exclusively an on-line measurement technique for the speed of sound in the fluid and a technique for eliminating flow disturbance effect on pressure sensors into the basic principle used in the existing “2 Pressures / 2 Systems” method. The new method has an inherent potential to yield results with higher accuracy and higher confidence. The high accuracy of the method is confirmed by the comparison of measured and predicted pressure ripple in a pump-pipe-valve system. Then, the method is applied to automotive fluid power pumps - power steering pumps. The measured results of source flow ripple and internal impedance are presented.
Technical Paper

Problems With Using In-Vehicle Acoustic Absorption Measurements to Develop Interior Trim Parts Based on Laboratory Measurements

2001-04-30
2001-01-1622
Setting accurate acoustic performance targets for trim components early in a vehicle program is essential to develop the vehicle on-time, with appropriate acoustical performance, at lowest weight, and at lowest cost. The laboratory measurement of acoustic absorption (ASTM C 423 and ISO 354) of flat stock trim parts is used to obtain these targets or the specific trim part is measured in a vehicle to obtain the acoustic absorption. However, the in situ measurement often does not agree with the laboratory measurement even if the variations between formed parts and flat stock materials are accounted for. A statistical energy analysis model is used to illustrate the problems with in situ absorption measurements. An approach to correct the in situ test method to obtain an approximation of the laboratory result is discussed.
Technical Paper

Progress in the Optimized Application of Simulation Tools in Vehicle Air Conditioning

2001-05-14
2001-01-1699
The paper focuses on the usage of simulation tools during the development of vehicle air-conditioning systems. The integration of simulation is explained at every stage of the process. It differentiates at which step the 3-D simulation properties are needed and where the advantages of 1-D tools decide its use. For each demand the most targeting way of calculation has to be chosen, facing properties like precision, hardware needs and especially modeling as well as calculation time along to the tightened development schedule. Examples are given from system layout to detailed optimization.
Technical Paper

R134A Suction Line Heat Exchanger in Different Configurations of Automotive Air-Conditioning Systems

2001-05-14
2001-01-1694
A suction line heat exchanger (SLHX) transfers heat from the condenser outlet to the suction gas. In a TXV (thermostatic expansion valve) system, the performance improvement with a 60 to 80 % effective SLHX is expected to be on the order of 8 to 10 % for capacity, and 5 to 7 % for COP for high outdoor air temperatures of 43ºC. In a FOT (fixed orifice tube) system, the performance improvement was calculated to be about 10 to 15 %. The calculated improvements have been verified experimentally within a few percent.
Technical Paper

A Software Tool for Noise Quality and Brand Sound Development

2001-04-30
2001-01-1573
For noise quality and brand sound design of passenger cars a unique software tool is currently used by our clients world-wide to evaluate and optimise the interior noise quality and brand sound aspects of passenger cars on an objective basis. The software tools AVL-VOICE and AVL-COMFORT are designed for the objective analysis of interior noise quality, for benchmarking, for the definition of noise quality targets and most important for effective vehicle sound engineering. With this tool, the target orientated implementation of the required interior noise quality or brand sound by predictable hardware modifications into passenger cars - for tailor made joy of driving - becomes feasible. The use of this tools is drastically reducing vehicle evaluation time and sound engineering effort when compared with traditional jury subjective evaluation methods and standard acoustic NVH optimisation procedures.
Technical Paper

Subjective Evaluation of NVH CAE Model Predictions Using an Operator-in-the-Loop Driving Simulator

2001-04-30
2001-01-1590
In the past several years there has been a significant effort to increase the reliance on CAE technology to guide the vehicle design process, with the accompanying effort to reduce or eliminate vehicle prototype testing during the early design phase. Since little or no representative hardware is available early in the design, a tool is needed which allows NVH Development Engineers to subjectively experience the results of NVH CAE model predictions in a realistic driving environment. This paper documents the development of a high fidelity NVH simulator, including both audio and vibration, and the integration of this simulator into an “operator-in-the-loop” Driving Simulator. The key development of this system is its ability to incorporate NVH CAE predictions into the simulated driving environment.
Technical Paper

Advances in Complex Eigenvalue Analysis for Brake Noise

2001-04-30
2001-01-1603
Brake squeal has been analyzed by finite elements for some time. Among several methods, complex eigenvalue analysis is proving useful in the design process. It requires hardware verification and it falls into a simulation process. However, it is fast and it can provide guidance for resolving engineering problems. There are successes as well as frustrations in implementing this analysis tool. Its capability, robustness and reliability are closely examined in many companies. Generally, the low frequency squealing mechanism is a rotor axial direction mode that couples the pads, rotor, and other components; while higher frequency squeal mainly exhibits a rotor tangential mode. Design modifications such as selection of rotor design, insulator, chamfer, and lining materials are aimed specifically to cure these noise-generating mechanisms. In GM, complex eigenvalue analysis is used for brake noise analysis and noise reduction. Finite element models are validated with component modal testing.
Technical Paper

Engine Internal Dynamic Force Identification and the Combination with Engine Structural and Vibro-Acoustic Transfer Information

2001-04-30
2001-01-1596
The vibration-generating mechanisms inside an engine are highly non-linear (combustion, valve operation, hydraulic bearing behavior, etc.). However, the engine structure, under the influence of these vibration-generating mechanisms, responds in a highly linear way. For the development and optimization of the engine structure for noise and vibration it is beneficial to use fast and ‘simple’ linear models, like linear FE-models, measured modal models or measured FRF-models. All these models allow a qualitative assessment of variants without excitation information. But, for true optimization, internal excitation spectra are needed in order to avoid that effort is spent to optimize non-critical system properties. Unfortunately, these internal excitation spectra are difficult to measure. Direct measurement of combustion pressure is still feasible, but crank-bearing forces, piston guidance forces etc. can only be identified indirectly.
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