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Developed to cut down on maintenance costs and increase the earning power of the vehicle, this family of suspensions provides for improved vehicular behavior - items such as stability, braking, cornering, and overall ride. The suspensions utilize a principle of providing a cushioned variable rate ride through the use of molded rubber springs. Floating walking beams distribute weight equally on both axles in the case of tandems. The axles are positively located by upper wishbones and lower torque rods. The parallelogram thus formed prevents windup and axle hop. The correct use of metals shows a substantial weight saving in the entire model range.

A new concept in conventional truck cab vibration isolation has been developed by Holland Neway International. The system provides a significant improvement in ride comfort for the truck cab occupants in the truck of the twenty-first century. The single point isolator incorporates inclined sleeve type air springs to achieve a very low natural frequency, typically 0.9 - 1.1 hertz. A unique variable geometry damping system is used in conjunction with the sleeve springs to allow the configuration to achieve significant improvements in vibration isolation. The passive variable geometry control operates essentially undamped until large displacement disturbances are encountered allowing maximum possible isolation performance. Since the isolator natural frequency occurs in a region where the human physiology is most tolerant of vibratory motion, a high level of ride comfort is achieved.

Exhaust gas air-fuel ratio (A/F) sensors are common devices in powertrain feedback control systems aimed at minimizing emissions. Both resistive (using TiO2) and electrochemical (using ZrO2) mechanisms are used in the high temperature ceramic devices now being employed. In this work a new mechanism for making the measurement is presented based on the change in the workfunction of a Pt film in interaction with the exhaust gas. In particular it is found that the workfunction of Pt increases reversibly by approximately 0.7 V at that point (the stoichiometric ratio) where the exhaust changes from rich to lean conditions. This increase arises from the adsorption of O2 on the Pt surface. On returning to rich conditions, catalytic reaction of the adsorbed oxygen with reducing species returns the workfunction to its original value. Two methods, one capacitive and one thermionic, for electrically sensing this workfunction change and thus providing for a practical device are discussed.

To reduce heat transfer between hot gas and cavity wall, thin Zirconia (ZrO2) layer (0.5mm) on the cavity surface of a forged steel piston was firstly formed by thermal spray coating aiming higher surface temperature swing precisely synchronized with flame temperature near the wall resulting in the reduction of temperature difference. However, no apparent difference in the heat loss was analyzed. To find out the reason why the heat loss was not so improved, direct observation of flame impingement to the cavity wall was carried out with the top view visualization technique, for which one of the exhaust valves was modified to a sapphire window. Local flame behavior very close to the wall was compared by macrophotography. Numerical analysis by utilizing a three-dimensional simulation was also carried out to investigate the effect of several parameters on the heat transfer coefficient.

Presenting a brand new approach to heat exchangers for engines, transmissions, hydraulic systems, etc. This new heat exchanger is made of only two pieces of circular extruded aluminum profiles: Core and shell. No soldering: The core and the shell is assembled by a minimum of automated work. In an oil to water cooling application, the active surface on the oil side of the core is enlarged by fins 0.2 mm thick, 0.3 mm spacing, and 3 mm high. The fins are made in unique production machines and enlarge the active surface area approximately five times compared to a conventional heat exchanger of the same dimensions. The principle utilizes the low pressure drop at laminar flow and avoids the disadvantage of low heat transfer after a certain laminar flow length. The result is approximately three times higher oil heat dissipation, combined with very low oil pressure drop, compared to conventional technique.

The design and development of a new four-stroke two-cylinder diesel engine family of 1.29 litre capacity for off road are discussed. The engine is in naturally aspirated and turbocharged and intercooled versions and rated from 11.9 kW/1500 rpm to 25.7 kW/2500 rpm. The engines were tuned for air and fuel flows, air utilisation, fuel air mixing, performance and emissions at steady state at a development lab and later certified in national labs. The high altitude capability of the TCIC was checked using a model. The engines rated at less than 19 kW satisfy India Generator set and off road norms of India and Europe equivalent to USTier4 standard, and at higher ratings, standard equivalent to US Tier4-interim. In the second part of the paper, the design of coolant and oil pumps, oil cooler for TCIC engine and the piston with steel oil control ring are discussed. The higher loaded TCIC engines use fillet hardened crankshafts of chromium molybdenum steel.

The performance of five positive k-factor injector tips has been assessed in this work by analyzing a comprehensive set of injected mass, momentum, and spray measurements. Using high speed shadowgraphs of the injected diesel plumes, the sensitivities of measured vapor penetration and dispersion to injection pressure (100-250MPa) and ambient density (20-52 kg/m3) have been compared with the Naber-Siebers empirical spray model to gain understanding of second order effects of orifice diameter. Varying in size from 137 to 353μm, the orifice diameters and corresponding injector tips are appropriate for a relatively wide range of engine cylinder sizes (from 0.5 to 5L). In this regime, decreasing the orifice exit diameter was found to reduce spray penetration sensitivity to differential injection pressure. The cone angle and k-factored orifice exit diameter were found to be uncorrelated.

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.

Recent research on carburized steels has demonstrated a correlation between the toughness properties of a carburized steel and the fatigue performance in combined load testing (high-cycle fatigue plus overload). The data presented suggest that, for applications where loads above the fatigue limit are encountered, both processing and alloying must be considered. Results from a number of investigations are reviewed to illustrate that high-cycle fatigue properties are controlled primarily by the processing, whereas toughness characteristics, such as resistance to random cyclic loading, are a result of the alloying.

Compacted Graphite Iron (CGI) has been recognized for years as a unique material possessing a fortunate combination of properties intermediate between gray iron and ductile iron. This material, for reasons outlined in this paper, is ideal for cylinder blocks, heads and other cast iron components for diesel engines. It makes possible casting weight savings of up to 1/3 and/or increased power output. This paper will outline reasons why this is now possible, whereas it has seldom been applied in volume production heretofore. Physical and mechanical properties of CGI, which provide the opportunity for weight reduction and increased power, are discussed. Currently, most diesel engine cylinder blocks, heads, liners and many other castings are produced from gray iron, which requires relatively heavy sections to provide the strength, stiffness and durability necessary for commercial application.

Abstract In view of the combustion efficiency and emission performance, various new clean combustion modes put forward higher requirements for the performance of the fuel injection system, and the cavitating two-phase flow characteristics in the injector nozzle have a significant impact on the spray atomization and combustion performance. This article comprehensively discusses and summarizes the factors that affect cavitation and the effectiveness of cavitation, and presents the research status and existent problems under each factor. Among them, viscosity factors are a hot research topic that researchers are passionate about, and physical properties factors still have the value of further in-depth research. However, the importance of material surface factors ranks last since the nozzle material was determined. Establishing a more comprehensive cavitation–atomization model considering various factors is the focus of research on cavitation phenomena.

Correlations of simply calculated fuel spray parameters with measured ISFC and smoke trends in a swirling direct injection diesel engine are described. These are based on a large number of results from experiments carried out on a 120.7 mm bore engine in which the induction swirl could be varied. The correlations indicate that (i) the fuel spray tip velocity at impingement on the chamber wall and (ii) the ‘crosswind’ over the spray at impingement have important influences. Based on these it is deduced that engine speed-related turbulence is a rate-controlling factor in DI diesel combustion.

The West Virginia University (WVU) Transportable Heavy-Duty Vehicle Emissions Testing Laboratory was employed to conduct chassis dynamometer tests in the field to measure the exhaust emissions from heavy-duty buses and trucks. This laboratory began operation in the field in January, 1992. During the period January, 1992 through June, 1993, over 150 city buses, trucks, and tractors operated by 18 different authorities in 11 states were tested by the facility. The tested vehicles were powered by 14 different types of engines fueled with natural gas (CNG or LNG), methanol, ethanol, liquified petroleum gas (LPG), #2 diesel, and low sulfur diesel (#1 diesel or Jet A). Some of the tested vehicles were equipped with exhaust after-treatment systems. In this paper, a total of 12 CNG-fueled and #2 diesel-fueled transit buses equipped with Cummins L-10 engines, were chosen for investigation.

Hydrogen ICE can achieve carbon neutrality and is adaptable to medium and heavy-duty vehicles, for which electricity is not always a viable option. It can also be developed using high-quality conventional diesel/gasoline engine technology. Furthermore, it allows for the conversion of existing engines to hydrogen ICE, making it highly marketable. The reliability and durability of MPI hydrogen ICE is better than that of DI, and MPI has an advantage over DI in terms of cruising range because the low-pressure injection of hydrogen reduces the remaining hydrogen in the tank. Improving MPI output is, however, an important subject, and achieving this requires suppressing abnormal combustion such as pre-ignition. In this study, an inline four-cylinder 5L turbo-charged diesel engine was converted to a hydrogen engine. Hydrogen injectors were installed in the intake ports and spark plugs were installed instead of diesel fuel injectors.

The Second Auto Works of China has been extensively using boron steels in its truck manufacture with accumulation of experience over 20 years, four grades of boron steels are now in regular production with accumulated consumption of about 450,000 tons. Another three grades are in different R&D stages. A new steel series based on silicon manganese, vanadium and boron has come into being. All manufactured parts must stand field teats on very difficult terrain on the Chinese land. It has been proved by practice that boron steels can cope with requirements of truck design, manufacture and field usage. They are economical not only financially, but also on strategic material consumption. Also presented are discussions on boron steel peculiarities.

A new unitized heavy duty axle oil seal (Figure 1) has been developed that meets in whole objectives that are demanded by the modern truck owner. These objectives are, unitized assembly, simplified no tool installation, damage resistance, external contaminant exclusion, use in aluminum hubs and a proven reliability and ultimate life capability. This paper discusses the advanced design which is supported by extensive laboratory and field testing in excess of one hundred million vehicle miles. Typical laboratory testing included intensive functional life bench testing, comparative dust testing and cold follow-ability and fracture tests. The field testing has made use of a broad array of vehicle applications from continuous duty coast-to-coast transport in Canada to short haul quarry pit and numerous city traffic fleets. The results of the laboratory and field testing are discussed, revealing how this design has met the demands of the modern seal user.

Maintaining the fuel temperature and fuel system components below certain values is an important design objective. Predicting these temperatures is therefore one of the key parts of the vehicle’s thermal management process. One of the physical processes affecting fuel tank temperature is fuel vaporization, which is controlled by the vapor pressure in the tank, fuel composition and fuel temperature. Models are developed to enable the computation of the fuel temperature, fuel vaporization rate in the tank, fuel temperatures along the fuel supply lines, and follow its path to the charcoal canister and into the engine intake. For diesel fuel systems where a fuel return line is used to return excess fluid back to the fuel tank, an energy balance will be considered to calculate the heat added from the high-pressure pump and vehicle under-hood and underbody.

The good relationship between the spray condition in the intake manifold and the combustion characteristics is required. Firstly by this report it was tried the visualization and observation of spray of gasoline injection. It was mainly photographed when injection just began and the spray impinged on a intake valve. The photographs of fuel spray were taken by a image converter type high speed camera. The characteristics of the fuel spray injected in early injection period is influenced with fuel pressure and flow rate of fuel. The atomizing phenomenon of tip fuel of spray could be visualized. The atomizing process in early injection period are differ from that in stady-state spray. And the picture of spray at impingement on the intake valve was shown too. The atomizing condition on the valve surface could be observed visually.

This recommended practice covers the criteria for steps, ladders, walkways, platforms, grab rails (handrails), grab irons, guardrails, and entrance openings as they relate to aiding the operator and/or servicemen in performing their functions on the vehicle.