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This paper summarizes the techniques and guidelines which were used to reduce the driver perceived noise level of a 145-210 HP series of agricultural tractors. Graphs of case study test results and comments on subjective noise quality are provided to guide the acoustic novice through the complexities of the vehicle sound environment in a methodical problem solving format.

Contact the appropriate representative of the 2023 Noise and Vibration Conference and Exhibition.

Health related problems in over populated areas are a major concern and as such, there are specific legislations for noise generated by transport vehicles. In diesel powered commercial vehicles, the source for noise are mainly related to rolling, transmission, aerodynamics and engine. Considering internal combustion engine, three factors can be highlighted as major noise source: combustion, mechanical and tailpipe. The tailpipe noise is considered as the noise radiated from the open terminations of intake and exhaust systems, caused by both pressure pulses propagating to the open ends of the duct systems, and by vortex shedding as the burst leaves the tailpipe (flow generated noise). In order to reduce noise generated by vehicles, it is important to investigate the gas interactions and what can be improved in exhaust line design during the product development phase.

Diesel injection equipment is required to be more accurate and higher in pressure to meet the increasingly strict emission, fuel consumption regulations and higher engine performance. It also needs to achieve a number of requirements such as robustness against diversified market fuels, easy installation to engine, etc.

The new 5480 Reach Truck, designed at Dynamic Industries, introduces a movable frame between the main frame and the telescopic boom. The use of this movable frame allows the usually fixed boom pivot to be elevated for greater lifting heights with smaller boom sections. By combining the motions of the boom and the movable frame, horizontal motion at the boom tip is possible without moving the truck. With the movable frame, the total machine height and length can be reduced for a given lifting goal. Another advantage of the movable frame is the ability to reach further below grade than is now possible in the industry. The 5480 Reach Truck has a maximum lift of 54 feet (16.5 meters) and can reach 24 feet (7.3 meters) below-grade.

The LTL-900 Transi-Lift crane features front and rear crawler-mounted load platforms connected with a hoist-supporting five foot diameter pipe section. The pin-together main boom is available in lengths up to 400 feet and completely disassembles for ease of transport to and from the jobsite. The crane requires three operators and can hoist, boom, swing and travel simultaneously with maximum loads. Upending, moving and setting large refinery vessels is facilitated by the mobility of the crawler-supported crane on unprepared surfaces. Up to 1000 tons of 36 ton concrete beams or equivalent are required as counterweight to develop the ANSI B30.5 approved capacities.

A unique shuttle bus is being constructed by Minicars, Inc., and Walter Vetter Karosserie-werk for Denver’s Transitway/Mall. The bus is designed for frequent stop, low speed service in a downtown pedestrian environment. It features a very low floor and multiple wide doors for rapid passenger boarding and deboarding. Two versions will be supplied for comparative evalation, a low noise diesel configuration and a battery-electric configuration. Either version can subsequently be converted to the alternative propulsion system.

The paper addresses some aspects of an ongoing research on a commercial compact excavator. The interest is focused on the analysis and modelling of the whole hydraulic circuit that, beside a load sensing variable displacement pump, features a stack of nine proportional directional control valves modules of which seven are of the load sensing type. Loads being sensed are the boom swing, boom, stick and bucket, right and left track motors and work tools; instead, the blade and the turret swing users do not contribute to the load sensing signal. Of specific interest are the peculiarities that were observed in the stack. In fact, to develop an accurate AMESim modelling, the stack was dismantled and all modules analysed and represented in a CAD environment as 3D parts. The load sensing flow generation unit was replaced on the vehicle by another one whose analysis and modelling have been developed using available design and experimental data.

Despite the general similarity of U.S. and European heavy trucks, there are differences in design properties that affect braking and turning performance. A European tractor-semitrailer was studied for the purpose of comparing its properties to those of U.S. vehicles and assessing the comparative performance. Mass, suspension, and braking system properties of the European tractor and semitrailer were measured in the laboratory and on the proving ground. Turning and braking performance qualities were evaluated by computer simulation and by experimental tests. In turning performance the European combination had a 9 percent advantage in rollover threshold, compared to a generic U.S. vehicle with properties that were in the midrange of U.S. design practice. Higher suspension roll stiffness and higher chassis weight on the European tractor and semitrailer accounted for the higher threshold.

A distributed sensor is created to sense the rate of change in deflection of beam-like structures such as crane booms. This sensor will be useful in electrohydraulic compensation of boom deflections. The sensor is made of an array of strain-sensitive segments such as strain gages or piezoelectric film. In this example, segments of piezoelectric film convert strains on the surface of a vibrating beam into electrical outputs. These outputs are connected to low impedance signal conditioners. The output of the signal conditioners are then interpolated with a weighting vector that incorporates Lagrange polynomials, specified boundary conditions, and the desired location(s) of measurement. A simple linear combiner circuit combines the electrical outputs into the deflection velocity at the desired points.

Valve blocks are the key parts in hydraulic systems. A feature-based product model is the foundation of the CAD/CAM system for valve blocks--VBCADAM. This paper mainly analyses the design procedure of valve blocks, the application of feature-based design and modeling, object-oriented approach in the development of VBCADAM, such as feature definition and classification, the frame description of features, structure of product model and also the application of the product model in VBCADAM.

The hydraulic industry, in order to meet the upward trend in size and mechanization of mobile type vehicles, has continued to provide increased horsepower per cubic inch of installed space in both pumps and motors and new control devices, such as pilot operated, solenoid or hydraulically operated and electro-hydraulic servo valves. These features, which are required for the optimum transfer and control of power to do useful work, are discussed in this article.

New low loss valves have been designed for an existing railroad air brake compressor. Prototypes of these valves have been built and tested in the laboratory. These valves increase the efficiency of the compressor by 13% when operating at full load and rated speed with corresponding improvements at lower speed and when unloaded. Total operating hours on the test compressor with the high efficiency valves installed total over 4000 as of 1/1/86. The Association of American Railroads has a committee working to find ways of increasing locomotive and rolling stock efficiency and hence reducing fuel costs. As part of this task, the committee considered ways of reducing the power consumption of the air brake compressor. We at Worthington Dresser were asked whether the technology we had developed to increase the efficiency of large stationary compressors could be applied to the locomotive compressor.

This article introduce a kind of displacement sensor and the matching circuits with it. The sensor can be used to measure the displacement of cartridge insert valve in the medium of pressure with amplitude ranged from 0 Mpa to 32 Mpa.

The transition from ICE to electric power trains in new vehicles along with the application of advanced active and passive noise reduction solutions has intensified the perception of noise sources not directly linked to the propulsion system. This includes road noise as amplified by the tire cavity resonance. This resonance mainly depends on tire geometry, air temperature inside the tire and vehicle speed and is increasingly audible for larger wheels and heavier vehicles, as they are typical for current electrical SUV designs. Active technologies can be applied to significantly reduce narrow band tire cavity noise with low costs and minimal weight increase. Like ANC systems for ICE powertrains, they make use of the audio system in the vehicle. In this paper, a novel low-cost system for road induced tire cavity noise control (RTNC) is presented that reduces the tire cavity resonance noise inside a car cabin.

This paper describes a method to determine control losses, i.e., losses solely due to regulation of velocity of the load, for various variable pump systems as compared to conventional fixed pump-open center, by-pass valve systems. The method is graphically illustrated in load pressure-flow diagrams where the different control losses are shown. Loci of comparative control losses are plotted in the load pressure-flow diagram and if the pressure-flow-time duty cycle is known, the total difference in control energy loss/duty cycle can be computed for a particular machine. This energy loss is then converted to the difference (gain or loss) in fuel consumption and cooling requirements. Finally, results from test runs with a backhoe-loader and three different operators are shown.

Based on 3- dimensional velocity data at intake valve exit area of typical SI engine intake ports (horizontal and sloping directed ports) measured by hot wire anemometry in a steady flow rig, the magnitudes and compositions of inflow angular momentum flux and swirl ratios at the end of induction process generated by each velocity component were computed at different intake valve lifts and distances along valve axis. A microscopic evaluation method was provided for evaluating intake port characteristics according to intake valve exit flow field.

Conventional accumulator charging valves operate automatically and reliably in constant flow industrial hydraulic systems. By contrast, these valves do not necessarily perform reliably in variable flow mobile hydraulic systems because the accumulator circuit charging pump flow changes with the engine speed. Occasionally, the valve sticks in a transitional condition which neither allows the accumulator to fully charge nor lets the charge pump unload. This paper describes the operation of conventional and mobile type accumulator charging valves and describes how the spool design pilot circuit valve improves the reliability of the mobile machine accumulator charging valve.

Most fertilizer application systems are not capable of variable rate adjustments “on-the-fly”. To change the application rate, the farmer must dismount the tractor and change the gear ratio mechanically (i.e. via gears, chains, etc.). Air seeder manufacturers have come up with their own unique solutions to address this problem, usually involving electrohydraulics. At present there are older seeding units that perform adequately, but do not have the variable rate option. A retrofit is therefore very desirable for these units. In this paper, the feasibility of a simple hydraulic proportional valve and variable speed motor circuit is employed to replace the gears and chains. The unit is integrated with a microcontroller to provide compensation to the nonlinear properties of a proportional valve, and in turn provide a very accurate feedrate. In addition, direct user input from the cab of the tractor is possible, allowing on-the-go rate changes.

The new X-by-Wire systems under study for commercial and heavy-duty vehicles, as well as for Agricultural Tractors, are increasingly real autonomous systems, capable to autonomously control a vehicle functionality, actuating the operator's commands, or managing in a complete autonomy a machine function. These application need an higher Performance Level from the functional safety point of view, due to the risk of a malfunction consequence. The paper deals with a new concept hydraulic spool valve that allow the design of new safer and more compacted hydraulic circuit architectures, ensuring higher safety performance levels. The architecture presents advantages both from performance (precision, fastness), both from operational point of view. The paper will focus in particular on safety and control topics. The new patented valve presents a secondary rotary type actuator connected to a sleeve interposed between the spool and the valve body, thus composing a roto-translating valve.