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Compact excavators are designed to perform a variety of functions within a small vehicle envelope. The vehicle size presents constraints on the structure as well as the hydraulic system. A unique open-center hydraulic system has been designed and developed which optimizes system performance, size, and cost. The hydraulic circuit was designed to provide smooth, reliable operation of as many as ten vehicle functions simultaneously.

This paper compares the performance of a radius lip wiper and sharp lip wiper. Both wiper styles were tested for a paired comparison of leakage, wear, and ingression resistance. The results show that using a radius lip wiper allows the fluid to adhere to the rod, giving the fluid a greater opportunity to reenter the system instead of being scraped off by the wiper and accumulating as apparent leakage. This decrease in apparent leakage does not have an adverse affect upon the wipers original intended function: preventing ingression of contamination into the hydraulic system.

This paper relates to the increase in speed and pressure ratings of piston type hydraulic pumps and motors. Such units are typically used as components in hydrostatic transmissions. Without a substantial change in basic design, the introduction of fixed losses to fulfill these ratings adversely affects the partial load efficiency of those units.

The electronics in the JCB Wheeled Loader represent an integration of the requirements of the operator, the needs for configuration on several models of loader in several languages, and the need for data collection and diagnostic capabilities. A number of challenging technologies are used in the electronics including a large custom LCD panel with backlighting, LED warning indicators, automatic 12V/24V operation, real-time clock recording of fault conditions, and CE approval. The Windows-based software tool allows settings to be altered and logged data to be viewed to monitor the operation of the loader and assist with diagnostics of faults.

In many areas, neural network technology has made a successful transition from theory to practical application, primarily due to the advances that have been made in computer technology and digital signal processing. Research at the University of Saskatchewan over the past few years has focused on applying neural network technology to fluid power systems. This paper will examine four projects that have been initiated by the authors and their graduate students which use neural networks for purposes of open loop pattern following, multiple input - multiple output control, indirect measurement of actuator displacement, and hydraulic component identification. A brief introduction to static and dynamic neural networks is given. Descriptions of the individual project objectives, the experimental implementation of neural networks to achieve these objectives, and some typical experimental results are considered.

Many mechanical systems employing fluid power use one or more valves to control fluid flow. Often these valves can be quite complex, with many inlets and exits, reversing flow, flow and pressure control, and other unique features. It is desirable to model these valves and the associated fluid and control logic circuits with software during the design phase, and explore the effect of design changes on system performance using simulation and other analyses without having to build and modify expensive prototypes. A number of commercially available software packages offer various methods for “graphically modeling” dynamic systems, and some, offer the user pre-defined libraries of hydraulic components that greatly speed the modeling process. However, the variations on valve design are unlimited, and it is often necessary to model a hydraulic valve that has not been previously defined. This paper describes an approach allowing essentially any valve configuration to be modeled.

This paper evaluates the acceleration transmissibility in the Z axis, from the floor of the cab to the seat, in a wheeled backhoe loader when performing different tasks. The evaluation consisted of two operators performing four different tasks (i.e., idling, digging, riding with a load, and riding without a load) using the same piece of equipment. The transmissibility was determined by evaluating the ratio of vibration at the floor and the seat in the Z axis. The results showed that the seat was amplifying the vibration levels particularly at the lower frequencies, and may not be sufficient to protect the operator from long-term effects of vibration exposure.

The application of site-specific agriculture has created a rapid need for technology in the farming community. An area of particular interest is that of utilizing spatially related data to more efficiently apply crop inputs. This has commonly been accomplished through the analysis of field characteristics, the use of variable rate application of farming inputs, and the analysis of yield outputs. Global Positioning Systems have been utilized to provide the real-time location information necessary for correlation of mapping and application systems. The techniques presented in this paper describe the application of navigation systems to agriculture, as navigation overcomes many of the limitations of standard GPS systems. This navigation research has spurred the development of a coupled GPS and INS system designed to advance the state of Site-Specific Agriculture.

SAE J1939 is an emerging communications protocol for on-board electronics in agricultural and construction equipment as well as for heavy duty on-highway equipment. The standard supports ECUs with both statically and dynamically configured addresses. This paper examines the dynamic addressing process, the process for ECUs that select addresses during initial power-up. A state diagram is proposed to implement the process described in the standard. Simulation results of systems with up to 100 dynamically configured ECUs are presented. Use of a pseudo-random delay after a power-ON self test was successful in minimizing bus-off collisions and allowed initialization times of under 1 second for 30 ECU systems. Minimum bus-off states during initialization of 30 ECU networks occurred with pseudo-random delays having a range of 0 to 15 ms.

Precision farming involves doing the right things in the right place at the right time. Combine yield mapping systems are documenting considerable yield variation within typical fields and should encourage improved crop management for higher profits and less impact on the environment. Variety choice, pest control, drainage, soil type, soil fertility, tillage practices, crop rotation, plant stands, and topography are a few of the factors causing yield variation. Managing these causes will require a much more detailed, yet holistic approach to crop production. Precision farming tools make on-farm research easier, which should help producers make more informed management decisions.

This paper reviews the theory and application of the “success run” test, found in reliability assessment applications, among others. A “success run” is a series of n independent tests without failure. The mathematical basis of the classical, non parametric success run test is reviewed, and it is shown with examples what can be said about the relation among reliability, confidence and sample size. The Bayesian success run is developed using the uniform distribution as prior distribution of reliability. This is further extended to include cases of uniform priors where 0< A < R < 1. The classical non-parametric case is reexamined and a natural prior distribution is revealed for the special case when one's only prior assumption is: 0 < A ≤ R ≤ 1. Finally, some comparisons are made among these models and it is shown that the lower confidence bounds on reliability, using these conservative priors, converge rather rapidly to results obtained using the classical non-parametric model.

Electronics content in off-highway vehicles and machinery is increasing and with it the total of the embedded control system software code. This paper focuses on the off-highway embedded software development process, and the need for a tool kit that will provide a surge in software productivity to meet market demands. Software productivity is measured by the cost to develop, time to market, the reliability and maintainability of the software. Current software design techniques are presented and critiqued. A new approach using an integrated tool set is presented. This set includes interoperable commercially available tools that allow engineers to develop control strategies, capture software requirements, automatically generate code, test the software, and validate the software on the production target. Documented improvements in software productivity using an integrated tool set are included in the closing.

A new powershift transmission concept for specific market segments of backhoe loaders and telescopic boom handlers has been designed, thoroughly lab and field tested and is now in full production. This new transmission is identified as the T16000. The concept is a result of extensive market analysis, customer interviews and study of vehicle performance requirements. OEM requirements in terms of reliability and quality have been considered. New technologies such as electronic modulation for directional clutches and electric/hydraulic modulation of the range clutches have resulted in an excellent shift quality vis-a-vis to application requirements and/or driver preference. A special protection system (mechanical) integrated in the control valve protects the transmission from engaging two clutches at the same time, preventing a drivetrain lock-up. All sensors are integrated in the valve body and are totally sealed according to European Standard IP67 specification.

A peculiarity of all-wheel drive off-highway vehicles is that their running abilities (cross-country mobility, tractive and velocity properties, turnability and the like) depend not only on total traction effort but also on its distribution between driving wheels. The latter is in great measure determined by actuating vehicle system and characteristics of the mechanisms installed in power dividing transmission units, i.e. in interwheel, interaxle reduction gears, and transfer cases. The characteristics of locking performance of these mechanisms regulate the circumferential force distribution between driving wheels and, respectively, a vehicle's performance indicators. Such mechanisms have been created and are being created in a multitude. The classification of power dividing mechanisms and system is given. They provide a high level of the traction performance of all-wheel drive off-highway vehicles and agricultural tractors, in particular.

As the use of electronics increases in vehicles of all kinds, multiple manufacturer compatibility issues begin to dominate the system integration. Functionality of electronics is often repeated and duplicated, increasing costs. In order to reduce costs it is some times necessary to combine the functionality of multiple units into a single package. With the combination of power amplifier electronics and microprocessors, Agile has been able to integrate several vehicle functions into an integrated package. A thorough understanding of the vehicle powertrain dynamics is a critical requirement in developing fully integrated control electronics. Development of integrated electronics begins with a full vehicle model and simulation, followed by prototyping with known electronics before a cost optimized design is proposed. Discussion in this paper will cover full vehicle simulation and assumptions to full vehicle performance and results.

Like all industries, the fluid power industry is under increasing pressure to identify and use hydraulic fluids that offer higher performance, improved fire safety, and exhibit improved environmental and toxicological behavior. Recently a novel hydrolube composition has been developed that is capable of being used in hydraulic pumps at pressures of 34.4 MPa (5000 psi) and greater*. In addition to being a Group 1 Fire Resistant Hydraulic Fluid according to the new Factory Mutual Research Corporation's testing methodology, this high-performance hydrolube also exhibits excellent biodegradability and toxicology properties. The objective of this paper is to discuss pump performance, fire resistance, and environmental and toxicology properties of this fluid..

In the application of direct fuel injection to an SI engine the fuel spray characteristics such as droplets velocity and diameter, as well as the penetration length in the combustion chamber - but especially their variation with engine speed and injected quantity - are determining criteria for a mixture formation with the required quality. These characteristics are of particular importance for high speed engines because of the large range of speed variation and become stringent for high speed two-stroke engines where a very short mixture formation time is imposed.

The exhaust emissions from small engines in general and marine engines in particular have come under scrutiny over the past few years as new exhaust emission regulations have been proposed and put into force. The standard method for exhaust emission sampling of outboard marine engines is to analyze raw exhaust in the exhaust manifold of the engine. In this study a total dilution sampling system for the gaseous emissions, similar to what is used for light and heavy duty vehicles and engines, and a separate water sampling method were used to evaluate the exhaust emissions from stock two and four stroke outboard marine engines.

The two-stroke engine, by its nature is very dependent on the unsteady gas dynamics within an exhaust system. This is demonstrated by the tuning effects on two-stroke engines, which have been well documented. In consideration of current emissions legislation, a two-stroke engine can be fitted with a catalytic converter for the outboard, utility or automotive markets. The catalytic substrate represents a major obstruction to the flow of exhaust gas, which hinders the progression of the main exhausted pulse, and in turn effects the scavenging of the cylinder and ultimately the performance of the engine. Within this investigation, a 400 cc direct injection two-stroke engine was used with various catalysts positioned at different distances from the exhaust manifold. Comparison tests were performed between a fully lit off catalyst and a non-operational bare substrate.

This paper analyzed and studied the in-cylinder flow in two engines. Both are two-stroke loop scavenging 8-cylinder in-line engines. One cylinder diameter is 150mm and the other is 160mm. For researching its loop scavenging performance, one cylinder of both engines is examined. The upper section of the cylinder above the ports is cut off and replaced by a glass one, and the cylinder head is replaced by a plexiglass plate. Then they are mounted on the test bench. A metal screen is put in the glass cylinders. Threads are tied at the screen cross points. The direction of flow in cylinder can be visualized when the air flows. A kind of instrument, named Hot Ball Anemometer, is applied to measure the air flowing speed. The diesel's loop scavenging performance can be realized and satisfactory results obtained.