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An international standard for nonroad engines has been developed that comprises gaseous and particulate emissions measurement procedures, smoke testing, test cycles, and an engine family and group concept. Through a joint effort of industry and government agencies, ISO 8178 has become the basis for emissions legislation in the USA, the European Union and Japan and of the International Maritime Organization. The ultimate goal of worldwide harmonization for the worldwide engine industry has been reached, but much effort is still needed to maintain the level of harmonization achieved today. The validity of ISO 8178 has been demonstrated on a round robin test with three engines of 19 to 170 kW circulated around 28 test laboratories. Test-to-test repeatability was generally lower than 10 %. Lab-to-lab variability was less than 10 % for NOx and particulates, and over 25 % for HC and CO. The equivalence of partial flow and full flow dilution systems for particulates has been proven.

Six heavy-duty diesel engines were tested for exhaust emissions on the ISO 8-mode nonroad steady-state duty cycle and the U.S. FTP highway transient test cycle. Two of these engines were baseline nonroad engines, two were Tier 1 nonroad engines, and two were highway engines. One of the Tier 1 nonroad engines and both of the highway engines were also tested on three transient cycles developed for nonroad engines. In addition, published data were collected from an additional twenty diesel engines that were tested on the 8-mode as well as at least one transient test cycle. Data showed that HC and PM emissions from diesel engines are very sensitive to transient operation while NOx emissions are much less so. Although one of the nonroad transient duty cycles showed lower PM than the steady-state duty cycles, all four of the other cycles showed much higher PM emissions than the steady-state cycle.

This paper proposes a new flexible system concept applicable to diesel engines which will achieve the compatibility of high BMEP (Break Mean Effective Pressure) and low fuel consumption. The high BMEP means constant power from low speed to high speed (the power density will be 60ps/liter for truck applications, 87ps/liter for marine applications and 109ps/liter for racing boats). BMEP will be over 32kg/cm2. The low fuel consumption means a wide range of speed and torque having a good match to the best turbocharger efficiency. Before feasibility testing of an engine a basic simulation has been done and is introduced in this paper.

Bubbles in working fluids have much influence on the performance of fluid power systems. One of the authors has developed a novel device for bubble elimination capable of eliminating bubbles and decreasing dissolved gases using swirl flow. In this paper, performance of bubble removal in oil flow is studied through numerical analysis of the swirl flow in the device. This paper also documents a reduction of oil temperature rise and removal of entrained air from the working fluid in the hydraulic circuit by use of the device. It has been confirmed that the device is effective keeping the oil temperature low in the fluid power system.

Cavitation is a common and usually undesirable phenomenon in hydraulic systems. Understanding the basics of cavitation phenomenon as well as detecting existing cavitation are important in order to prevent cavitation in hydraulic systems. In this paper past studies of orifice cavitation are discussed and also new studies of orifice and valve cavitation with hydraulic oils are presented. Cavitation behaviour of different kinds of orifices and a poppet valve have been studied. Studies were done with different cavitation numbers. Rough design guidelines for reducing and preventing cavitation in orifices and valves are presented.

Tribological systems in hydraulic pumps, motors and cylinders are considerably stressed by friction and wear. Working life of components in hydraulic circuits might be extended by the use of wear resistant materials. Modern processes like Thermal Spray Technology, Physical Vapour Deposition and Plasma Nitration enable the application of wear resistant coatings with excellent friction characteristics. A wide variety of diffe-rent coating materials is available with various proper-ties concerning surface hardness, surface structure and coefficient of friction. Thus, an adaptation of surface properties and loads can be achieved. This paper presents results from investigations of coated simplified specimen and from tests with coated fluid power components.

Due to increasingly stringent emissions legislation the four-stroke engine is beginning to replace the two-stroke engine for motorcycle and scooter applications over 50cc. However, because of its comparatively poor performance, the four-stroke unit is not replacing the two-stroke for moped applications which are restricted to 50cc. To meet forthcoming European legislation the two-stroke moped engine requires an exhaust catalyst which presents considerable durability problems when applied to this type of engine. This would not be the case with a four-stroke unit, so if its performance could be improved it would be an attractive alternative. This paper illustrates the difficulties facing four-stroke engines of this size, the improvements required, the benefits (and problems) of a multi-valve approach and possible means of improving performance.

Precision agriculture technologies and systems will significantly change food and fiber production as we move into the next century. Engineers have and will continue to contribute to this field through development of equipment and sensors, application of technologies such as remote sensing and computer modeling, creation and evaluation of precision agriculture systems, and management of technology development and implementation activities. Realization of the potential benefits of precision agriculture -- including both improvements in production efficiency and achievement of water, air, and soil environmental quality goals -- will require a partnership between engineering and other disciplines in both industry and the public sector.

A complete vehicle including engine has been developed with the main aims of fulfilling future noise and pollutant emission limits but also to satisfy customers demands in terms of comfort and low NVH level and good fuel economy. The engine layout and design features are discussed with the thermodynamic calculation and the optimisation of ports and the variable intake system. The modal analysis of the engine parts and the simulation of the surface vibrations shows the effect of acoustic measures and the obtained results. Ancillaries like CVT drive, double link lever engine mount, water cooling system, lubrication system, exhaust system with catalyst and secondary air are discussed. Characteristic diagrams and driving cycle emission show the achieved performance, low emissions and fuel economy.

A fuel pump has been developed that uses Twenty-first century technology for four-stroke two-cylinder EFI engines. Fuel system feedback, frequency modulation, and an entirely new drive motor design is part of this technology. Some of the torque required to drive the current automotive pumps is absorbed in the driving method of the gerotor elements. It is a documented fact that the centrifugal churning of fuel by the motor armature uses 1a at 12vdc. The regulating valve requires a minimal flow [9gph] over engine demand in order to operate the regulating valve with some stability. Because of high energy demand, it is necessary to submerge the pump in the fuel for cooling purposes. This renders the pump useless for applications where it must run without fuel for a short time. Heat is transferred to the fuel from the armature and by the dumping of excess fuel over the regulating valve.

This paper describes a new type of valve gear cam - MULTICAM - which consists of seven curves and allows an optimum cam profile design. In order to calculate the cinematic and dynamic values and to assess the minimum oil film thickness in the valve gear, the mathematical model of an ideal valve gear was used. In addition, the comparison of the results between the polysine cam and the new MULTICAM cam design was made. By means of the new cam design the Hertz pressures were reduced at the point of contact between the cam and the cam follower and the lubrication properties at the top of the cam improved.

High carbon, high chromium nickel and cobalt base alloys as well as intermetallic compound- type cobalt base alloy are the major valve seat insert (VSI) materials for heavy duty engine applications. Recently, several new valve seat insert alloys were successfully developed to replace these traditional nickel and cobalt base alloys. Experiments indicate that these new alloys provide similar or improved important properties, such as sliding wear resistance and hot hardness, and offer significant cost reduction compared to traditional alloys.

The problem of fuel consumption decrease in agricultural machinery may be addressed in several ways. One is to equip mobile agricultural machines (tractors, harvesters, sprayers, fertilizer spreaders, etc.) with on-board computers (BC) capable to measure the fuel flow rate, in particular, which will allow to decrease fuel consumption by these machines due to timely control of the technical conditions of the engine and optimization of the machine operation modes from the point of view of fuel consumption. The article describes a family of diaphragm chamber fuel flow transducers (FFT) for on-board computers of mobile agricultural machines, gives their technical characteristics and laboratory and field test results, and recommendations on connecting them to engines of various power specifications.

One-dimensional (1-D) modelling codes are now commonplace in engine simulation programs. Thermodynamic analysis associated with the unsteady gas flow through engine ducting is an important element within the modelling process. This paper reports on a new approach in analysing mass and energy transport through a pipe system using the mesh method. A new system has been developed for monitoring wave energy and gas properties, using a two-dimensional grid to represent the time-mesh boundary domain. This approach has allowed for refinement of the current mesh method by allowing more accurate monitoring of gas properties. The modified method was tested using measured results from a Single-Shot Rig. A CFD analysis was also conducted and compared with the new method. The new method performed very well on the range of pipe geometries tested.

Design analysts, who work with finite element shape optimization, face a daunting task of handling cylindrical parts like a pusher for a crimp. The shape vectors generated by any of the existing methods/tools cannot constrain nodes to move in a circular path. Since the pusher is not a complete cylinder and the loading is only along axial direction, shape optimization was performed after flattening out the cylindrical pusher. The existing shape optimization tools could now be applied to the flat plate. A numerical interpolation method, based on ‘Autodv’, has been used to generate shape vectors. Both weight and stresses have been brought down and the final design was verified with solid finite element analysis.

Occupant restraint system design for off-highway vehicles is examined from the standpoint of occupant comfort. Typical conditions of use for this class of vehicle subject the occupant, seat and restraint system to a wide range of occupant- and vehicle-induced movements both into and away from the seat belt. These types of movements in both static and retractable systems can create high seat belt loading and loss of comfort for the occupant. This loss of comfort may reduce the likelihood of seat belt use which will, in turn, reduce the overall effectiveness of the restraint system in the event of a collision or rollover. Solutions to this problem involve eliminating or counteracting the spring force of the retractor to reduce peak belt loads on the occupant. Several design solutions are examined for effectiveness in reducing occupant belt loads while maintaining overall safety.

This paper describes the development process, and design features of the new 74cc/rev Series 45 open circuit hydraulic pump. The development process was optimized through use of a disciplined set of technical tools and business practices. This resulted in a new pump that offers increased performance with significantly reduced size, fewer components, and increased modularity compared to competitive products. In addition these tools and processes will make the product easier to support, simpler to apply, and will reduce development time for future pumps in the Series 45 family.

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.

Previous papers from The Queen's University of Belfast have described a new non-isentropic branched pipe junction model for use in a one-dimensional gas dynamic simulation of a multi-pipe system subject to unsteady gas flow. Such assemblages are commonly found in the intake and exhaust systems of multi-cylinder engines. The model takes full account of the effect of pressure loss, due to change in flow direction, and tracks the properties and composition of gas mixtures through the junction. Although the validity of the model has previously been inferred by its use in a complete engine simulation, which accurately predicted parameter variation in a firing engine, the independent validation of the junction model by itself is only now demonstrated. To investigate the performance of the junction model a series of three-pipe junctions were tested by directing a single pressure wave through each of the previously quiescent junctions.

A method to deduce the operating air-fuel ratio from the fuel flow rate, fuel characteristics, and emissions was introduced by Spindt in 1965 for conventional (nonoxy-genated) fuels. This study expands the original method to encompass oxygenated fuels. The use of the expanded Spindt Method allows the equivalence ratio to be estimated more accurately at high oxygenated fuel blends. Two generalizations are developed and proposed. One of the methods is shown to provide a 8-10% improvement in equivalence ratio estimation at a 17%wt oxygen typically under the maximum SAE J1088 load condition. To evaluate the two proposed generalized Spindt Methods, a series of small engines and fuels were emissions tested to determine the utility of the generalized Spindt Methods for analysis of oxygenated fuels. Air-fuel ratio estimates from the proposed Spindt Methods were compared to the original Spindt Method to assess equivalence ratio estimation improvements.