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Two different concepts in hydro-pneumatic suspension struts are formulated to conveniently realize either hydraulic or pneumatic interconnections between the struts within different wheel suspensions. The formulation employs a compact strut design that integrates a gas chamber and damping valves within the same unit, and provides considerably enhanced working area to appreciably reduce the operating pressure. A transverse interconnection between the hydro-pneumatic struts in the roll plane is analyzed to investigate its static and dynamic heave and roll properties, and relative potential benefits in enhancing the roll properties, while retaining the soft heave ride. Different hydraulically and pneumatically interconnected strut configurations are analyzed for a heavy vehicle, with appropriate considerations of the fluid compressibility, while the feedback effects associated with the interconnections are emphasized.

As regulations for on-board diagnostics head toward the heavy-duty trucking industry, there are a variety of new communication concepts that will directly impact J1939 systems. ECUs on J1939 networks must support new standard diagnostic protocols and data. Vehicles must provide single-point access for concise OBD data sets that represent multiple ECUs. New technologies, such as wireless communication links, present completely new and different scenarios for diagnostic testing. Understanding these concepts and their implications is essential to designing a J1939 system that will integrate into the coming global OBD infrastructure.

Heavy-duty diesel on-board diagnostics (OBD) regulations are being phased in around the world with varying degrees of similarity. This is occurring at a time when heavy-duty diesel emission regulations are driving complex and elaborate emission control strategies. Unique circumstances led the European heavy-duty diesel market to adopt selective catalytic reduction (SCR) as the primary solution for meeting strict Euro 4 emission levels. This paper is a review of the challenges of diagnosing an SCR system based on the Euro 4 OBD regulation and considers the future challenges of SCR diagnostics that lie ahead in the North American market.

With the increase of operating temperatures and equipment availability, the need is emerging for hydraulic and lubricating equipment manufacturing companies to include new proactive parameters in their maintenance specifications. Not only will these parameters result in a better balance between equipment and oil health monitoring, but also increase the availability of the equipment. The first part of this paper will present principles of working for this innovative technique, (off-line as well on-line oil analysis information) to monitor the antioxidant concentration or oxidative health of the oil, as a complementary parameter to contamination analysis. The second part of the paper will highlight the capability of the RULER™, as a portable field technique for different case studies. By monitoring the antioxidant depletion end-users will avoid excessive base-oil degradation and/or varnish and lacquer formation as well abnormally operating systems.

Regulatory authorities are actively revising and updating the rules for on board diagnostics of diesel powertrains. Diesel oxidation catalysts are among the parts that will have to be monitored. This paper discusses some of the issues related to the feasibility of monitoring these catalysts. We concentrate on the effect of real world noise factors on the ability to distinguish marginal from threshold catalysts and demonstrate that with current sensor and catalyst technology the separation between the two is poor.

To remove the snaking mode of an articulated steer vehicle, an active steering system is proposed. First, the existing steering systems of articulated steer vehicles, including hydraulic-mechanical and hydrostatic steering systems, are reviewed. Then, a combined linearized model of the vehicle with a hydraulic-mechanical steering system is developed. By using this model, two passive methods to decrease the snaking, including an increase in the friction at the articulation joint and leakage across the cylinders are detailed. To overcome the shortcomings of these solutions, an active steering system is also introduced. It is shown that the proposed steering system not only removes the instability, but also improves the steering response of the vehicle.

Hydraulic fluid (HF) specifications for mobile construction equipment called JCMAS HK and HKB have been established by the Fuels and Lubricants Committee of Japan Construction Mechanization Association (JCMA). The specifications are designated by two viscosity categories of single grade and multigrade. Each category has ISO viscosity grade (VG) 32 and 46. The JCMAS HK oils are recommended for use in hydraulic systems designed at pressure up to 34.3MPa(5000psi) and to heat hydraulic fluid up to 100 °C. These oils also provide wear control, friction performance, oxidation and rust protection, seal swell control and filterability performance. Two piston pump test procedures were developed to evaluate lubricating performance of these oils under high pressure conditions. The JACMAS HKB oils are classified as environmentally friendly oils due to the additional requirement for biodegradability.

On-road emission measurements of 23 VN-trucks on a randomly chosen driving cycle, consisting of 10 miles two-lane and 8 miles four-lane road, showed tailpipe NOx emissions on fleet average of 0.96 g/bhp-hr, or 1.06 g/bhp-hr when including the time the exhaust gas temperature was below 200°C. Complementary measurements in a SET-cycle (13 point OICA -cycle) on a chassis dynamometer showed a tailpipe emission of 0.008 g PM per bhp-hr. Moreover, cost analysis show that the diesel fuel consumption remains unchanged whether the truck running on ULSD is equipped with a Combined Exhaust gas AfterTreatment System (CEATS) installed or not.

The dynamic behavior of heavy vehicles moving on roads depends on load magnitude and its distribution, and a special concern may be directed to tankers. Liquid cargo at partial filled levels exhibits sloshing during vehicle longitudinal displacement, generating some forces which might alter vehicle's directional response and traction control. To attenuate the sloshing dynamic effect, transversal plates (baffles) are placed inside the container but increasing the structural container mass, arising vehicle's mass center and decreasing vehicle's useful load capacity. An experimental study on the effects of fill level and number of baffles on the sloshing attenuation is presented. For doing so, an instrumented scaled experimental tank of elliptical transversal section is used with water as liquid cargo, and longitudinal sloshing force is measured.

The future of vehicle safety will benefit greatly from precrash detection - the ability of a motor vehicle to predict the occurrence of an accident before it occurs. There are many different sensor technologies currently available for pre-crash detection. However no single sensor technology has demonstrated enough information gathering capability within the cost constraints of vehicle manufacturers to be used as a stand alone device. A proposed solution consists of combining information from multiple sensors in an intelligent computer algorithm to determine accurate precrash information. In this paper, a list of sensors currently available on motor vehicles and those that show promise for future development is presented. These sensors are then evaluated based on cost, information gathering capability and other factors.

Field testing of an extended life coolant technology in Class 8 trucks, equipped with Caterpillar C-12 engines revealed excellent coolant life with negligible inhibitor depletion to 400,000 miles with no refortification and no coolant top-off. In separate evaluations in Caterpillar 3406E equipped trucks, extended corrosion protection and component durability were established out to 700,000 miles, without the need for refortification other than top-off.

In this paper finite element model of porous materials is used to improve the acoustical behavior of vehicle sound absorbers. The equation of wave propagation in the porous materials with rigid frame is presented after explaining the physical properties of these materials. The finite element formulation of governing equation and boundary conditions is obtained based on Galerkin method. Simulation results are compared with the corresponding results of the other validated papers and also verified by analytical results. Finally, effects of physical and geometrical parameters on the acoustical behavior of absorbers are studied. In addition, the influence of an air gap on the back of the material and also multilayer absorbers are investigated. It is shown that the acoustical behavior of these materials, particularly in the low frequency range, can be improved.

Biodiesel has been used to reduce petroleum consumption and pollutant emissions. B20, a 20% blend of biodiesel with 80% petroleum diesel, has become the most common blend used in the United States. Little quantitative information is available on the impact of biodiesel on engine operating costs and durability. In this study, eight engines and fuel systems were removed from trucks that had operated on B20 or diesel, including four 1993 Ford cargo vans and four 1996 Mack tractors (two of each running on B20 and two on diesel). The engines and fuel system components were disassembled, inspected, and evaluated to compare wear characteristics after 4 years of operation and more than 600,000 miles accumulated on B20. The vehicle case history-including mileage accumulation, fuel use, and maintenance costs-was also documented. The results indicate that there was little difference that could be attributed to fuel in operational and maintenance costs between the B20- and diesel-fueled groups.

Planetary gears in heavy truck gearboxes are normally manufactured by forging a blank, turning, hobbing, shaving and heat-treatment followed by grinding. Due to the size of the gear the net shape capability of PM methods can be cost effective alternatively to conventional manufacturing. Warm compaction and surface densification are two PM methods to reach high density and thereby high strength and fatigue properties. Typical characteristics for PM gears manufactured by these methods are outlined.

A revolution in mobile hydraulic equipment is occurring. Conventional hydraulic spool valves with hydromechanical pressure compensators are being replaced by valve assemblies with four valve independent metering with electronically-controlled pressure compensation. In the system described here, two of the four independent valves are active during metering. This new topology offers significant advantages due to the two degrees of freedom provided. In this paper, the theory behind a new method of flow control based upon load feedback is presented for two of the five distinct metering modes. In addition, a new algorithm for setting the supply pressure is presented which is also based upon load feedback.

A rotary diesel fuel injection pump (RDFIP) takes drive from the engine assembly of an automobile engine. The critical part of RDFIP is plunger, which reciprocates as well as rotates in the plunger sleeve. The main function of plunger is to inject high pressure atomized fuel to the engine cylinder. Diesel fuel acts as a lubricant between the plunger and sleeve. The wear between the plunger and plunger sleeve causes considerable reduction in injection pressure and the quantity of fuel to the combustion chamber, which ultimately leads to an inefficiency of the engine assembly. The modeling and simulation of such a multi-domain dynamic system poses a formidable challenge. The conventional techniques are simple inadequate for the modeling and simulation of multi-domain dynamic systems. Bond Graph Method (BGM) is ideally suited for the modeling and simulation of multi-domain dynamic systems.

Researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health studied alternatives to the use of diesel equipment in underground mines, as a means of reducing health hazards. Two of the alternatives being considered are battery-powered equipment and hydrogen-powered equipment. While battery-powered equipment is clean, recharging or replacing a battery takes longer and can be less convenient than refueling diesel equipment. In addition, the amount of electricity available from a battery is far less than the electricity available from a diesel hybrid configuration of comparable weight. Hydrogen-powered equipment faces similar challenges to those being faced by battery-powered equipment. However, if enough hydrogen can be put on-board the equipment quickly and conveniently via safe refueling options, then hydrogen-powered equipment can be competitive.

In severe - hot and humid - climates, Vehicles Air Conditioning Systems (AC systems) in use today suffers from a lack of performance and on a difficulty to efficiently meet the cooling load without causing a significant reduction in the performance of the internal combustion engine. This is especially true in applications where vehicles have long idling period and a lot of passengers, such as buses and passenger shuttles. An integrated cooling system has been implemented and tested in an Airport Passenger shuttle in order to improve fuel economy and cooling effectiveness in severe environment (up to 120 °F). The cooling system integrates a high-efficiency thermal storage technology (based on phase change materials) coupled to high performance compressors. Comprehensive performance analyses and testing of the high-performance system have highlighted many benefits of using the technology in such applications.

In this paper some design aspects related to external gear pumps balancing surfaces are studied, and some useful guidelines for designing bearing blocks balancing surfaces are suggested. In order to study bearing blocks axial balance, a numerical procedure for the determination of the pressure distribution inside the clearance bounded by gears sides and bearing blocks internal surfaces is firstly presented and applied. After, the influence of bearing blocks geometry and pump operating conditions on the widening thrust is highlighted, considering both constant and variable lateral clearance heights. Then, the computations are performed to evaluate the widening thrust variation as a function of bearing blocks relative tilt with respect to gears lateral sides, and both positive and negative bearing blocks tilts are evidenced and discussed.

The field of earth moving equipment is experiencing a transformation due to the introduction of more electronic control capability and advanced control concepts. Conventional hydraulic control systems are controlled by proportional directional spool valve. The construction of the spool valve is such that a given position of the spool determines the flow in and the flow out restriction sizes. Thus, metering in and metering out are dependent or coupled. A certain restriction size on the inlet corresponds to a certain restriction size on the outlet. Therefore, we have one degree of freedom. It can provide for good motion control but it cannot achieve energy saving potential at the same time. In this paper, the concept of ‘independent meter in / meter out’ will be emphasized. Decoupling of meter in from meter out provides for more controllability and potential for energy saving in overrunning load cases when compared with a conventional spool valve controlled hydraulic system.