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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.

This paper describes the design concept and characteristics created to develop a new 200 hp class crawler tractor and the subsequent test to assume the achievement of objectives. The new tractor provides a stable platform for good control of the dozer blade and ripper, a main frame for independent mounting of the hydraulically controlled power train and superstructure components, easy servicing of power train components, integration of the ROPS with the chassis, and a 210 hp engine at 2100 rpm.

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.

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 AVL International Commercial Powertrain Conference is the premier forum for truck, agricultural and construction equipment manufacturers to discuss powertrain technology challenges and solutions across their industries. The topics of the conference, which happens every two years, cover all five elements of a modern powertrain: engine, transmission, electric motor, battery and the electronic control which are used basically the same way in the quest for optimal efficiency and environmental compatibility. This event offers a unique opportunity for highly regarded professionals to address the synergy effects and distinctive characteristics of commercial vehicles, agricultural tractors and non-road vehicles, and industrial machinery. These proceedings are being co-published with SAE International, via a strategic partnership.

Organized in cooperation with SAE International, AVL’s International Commercial Powertrain Conference- ICPC, happens every two years. It is the premier forum for truck, agricultural and construction equipment manufacturers to discuss powertrain technology challenges and solutions across their industries. This event offers a unique opportunity for engineers to address the synergy effects and distinctive characteristics of commercial vehicles, agricultural tractors and non-road vehicles, and industrial machinery. In 2017, the 9th ICPC focused on alternative powertrain technologies and innovations improving operating efficiency. These proceedings focus on: • Future challenges for engines and emissions • Smart Technologies Changing Farming • Cyber Physical Systems in Agriculture Business • OEM View of the Future of the Construction Machinery Industry • Powertrain Developments • CO2 Reduction • CVT Transmission Platform Technology • Autonomous and Connected Trucks

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.

A cartridge type pivotal pin and bushing joint has been patented and is being tested and refined both in the laboratory and on construction machinery. It features “dry lubricated” (Teflon) bearings which are assembled and sealed prior to installation. It is suitable for heavy unit loads and use under severe wear conditions, such as in crawler track chains and loader bucket pivotal pin joints. A brief history of U. S. manufactured track pin joints is included to show the progress in extending the service life of these devices.

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.

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.

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.

Recently, application of electronics to construction machinery has proceeded rapidly, and various measuring techniques have been required for a large number of electronic control or monitoring systems. Measurement of true velocity notwithstanding the existence of shoe or wheel slips is one of them. Microwave Doppler radar is an ideal measuring method for the purpose and has been used in automotive applications for many years. However, these vehicular radars don’t provide satisfactory results in typical operating conditions of construction machinery. And there remains a lot of problems to be solved. For example, the relative error at low velocity of 1km/h or so must be reduced. In this paper, solutions of these problems based on data of the field computer simulations and mathematical analyses are described. This study led to the conclusion that the radar’s performance can be highly improved.

A new method to predict brake squeal occurrence was developed by MSC under contract to Ford Motor Company. The results indicate that the stability characteristics of this disc brake assembly are governed mainly by the frictional properties between the pads and rotor. The stability is achieved when the friction coefficient of the pads is decreasing as the contact force increases. Based on the results, a stable brake system can be obtained without changing the brake structure by incorporating the appropriate frictional coefficient in the brake system. The method developed here can be also used as a tool to test the quality of any brake design in the early design stage.

The paper covers a new generation of manual transmissions for light and medium-duty trucks, vans and buses, initially introduced in a 5-speed version. The product reflects levels of driving comforts which are new to this class of vehicle worldwide with respect to shiftability, shift feel, noise emission, efficiency and durability.

In order to reduce high-frequency harmonic noise produced by the blower in the auxiliary system of a fuel cell vehicle (FCV), a narrowband active noise control (ANC) method instead of conventional passive mufflers is adopted since the blower demands clean air condition and expects good acoustic performance. However, in ANC practical applications, the frequency difference between reference signal and actual primary signal, i.e., frequency mismatch (FM), can significantly degrade the high-frequency performance of narrowband ANC system. In this paper, a new narrowband ANC system is proposed to compensate for the performance degeneration due to the existence of FM and improve noise reduction at high frequencies. The proposed system consists of two parts: the Filtered Error Least Mean Square (FELMS) algorithm filtering the primary signals at wide frequency range other than those at the targeted frequencies, and the FM removal algorithm proposed by Yegui Xiao.

A farm tractor protection cab made of thin steel sheet pressings is described. The cab is designed and produced using entirely automotive-type procedures. Curved glasses and a dampening suspension of the glasses are found to be an important means of achieving a low noise level in the cab. Using the pressing technique when producing a steel cab makes it possible to give the various cab details rigidity with a minimum of material. When welded together, these details form a very stiff cab body, which gives the necessary mechanical strength. The curved surfaces, the radii, and the round forms, which from a tooling point of view are natural for pressed steel parts, also have a vibration-dampening effect on the entire cab construction, thus making it easier to design a quiet tractor cab. Mounted on a farm tractor of conventional design, the cab meets the noise rating number ISO N85.

Transfer function measurements are the basis for construction of conventional test based source-path-receiver model of a vehicle. Interior noise of a vehicle can be synthesized using source excitation (both acceleration at source and near source sound pressure level) and its corresponding transfer function (Vibro-Acoustic Transfer Function (VATF) and Acoustic Transfer Function (ATF) respectively) to the interior of vehicle. Ideally ATF should be linear and independent of sound source, dependent only on size of air cavities, body structure and its material characteristics in between receiver and source location. But practically because of the type of excitation signal used to excite the sound source and characteristics of sound source itself, there is a possibility of variations in amplitude of acoustic transfer function.

An acoustic control technique for reducing booming noise caused by road surface roughness is described. This noise, mainly in the frequency range between 25 and 40Hz and accompanied by a pressure sensation, is closely related to suspension vibration characteristics and the acoustic response of the vehicle compartment. A reduction method which separates the highest acoustic response from suspension resonance in this frequency region is proposed. An acoustic simulation model is used to estimate the effects of the luggage compartment on this noise and of trunk lid vibration characteristics in optimizing acoustic properties of the compartment. As a result, a frequency region for trunk lid resonance which lowers booming noise is obtained. Estimated booming noise reduction is experimentally confirmed in road tests. A study of human auditory characteristics is also conducted to ascertain the frequency range and booming noise level which produce uncomfortable sensations.