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The author states as his object a review of what has been done and what must be done to make tractors successful in operating on low-grade fuels, especially kerosene. He takes up in order the four principal methods in common use of applying heat to vaporize kerosene, pointing out the advantages and disadvantages of each method and of its modifications. The author then cites various experiments with different types of carbureters in burning kerosene, drawing at length upon his own experience in this connection. He cites difficulties with gas distribution, manifold condensation, pistons and spark-plugs and points out that carbureter design is inseparable from considerations of tractor engine and manifold design. That better progress has not been made in the past in developing kerosene-burning tractor engines is stated to be largely owing to the fact that there has not been sufficient cooperation between engine and carbureter manufacturers.

The objective of the study was to investigate the biomechanical response of the intact cranium. Unembalmed human cadavers were used in the study. The specimens were transected at the base of the skull leaving the intracranial contents intact; x-ray and computed tomography (CT) scans were obtained. They were fixed in a specially designed frame at the auditory meatus level and placed on the platform of an electrohydraulic testing device via a six-axis load cell. Following radiography, quasistatic loading to failure was applied to one of the following sites: frontal, vertex, parietal, temporal, or occipital. Retroreflective targets were placed in two mutually orthogonal planes to record the localized temporal kinematics. Applied load and piston displacement, and the output generalized force (and moment) histories were recorded using a modular digital data acquisition system. After the test, x-ray and CT images were obtained, and defleshing was done.

This paper shows development challenges for 6 liter heavy duty off-road diesel engines to meet the Tier4 final emission regulations with a base diesel engine compliant with Tier4 interim emission regulations. Even if an after-treatment system helps to reduce emissions, quite amount of particulate matters (PM) reduction is still necessary since a diesel particulate filter (DPF) system is supposed to be excluded in Tier4 final diesel engine. The objective of this research is to see if the base engine has a feasibility to meet Tier4 final emission regulations by a change of piston bowl geometry without DPF. Quite amount of PM can be reduced by piston bowl geometry because piston bowl geometry is a very important part that enhances air and fuel mixing process that help the combustion process.

The intent of this paper is to explain specific considerations necessary to successfully start up and use an axial piston hydraulic pump system at -30°C without changing to a winter-grade hydraulic fluid. The particular vehicle involved was a new design of agricultural tractor. Testing was done on drivetrain parts in a small cold room, and complete prototype tractors were tested in a large cold room. The modifications to the hydraulic system resulted in a vehicle which starts readily at -30°C and can start to steer in less than one minute.

A computational fluid dynamics (CFD) guided combustion system optimization was conducted for a heavy-duty diesel engine running with a gasoline fuel that has a research octane number (RON) of 80. The goal was to optimize the gasoline compression ignition (GCI) combustion recipe (piston bowl geometry, injector spray pattern, in-cylinder swirl motion, and thermal boundary conditions) for improved fuel efficiency while maintaining engine-out NOx within a 1-1.5 g/kW-hr window. The numerical model was developed using the multi-dimensional CFD software CONVERGE. A two-stage design of experiments (DoE) approach was employed with the first stage focusing on the piston bowl shape optimization and the second addressing refinement of the combustion recipe. For optimizing the piston bowl geometry, a software tool, CAESES, was utilized to automatically perturb key bowl design parameters. This led to the generation of 256 combustion chamber designs evaluated at several engine operating conditions.

In high pressure hydrogen injection hot surface ignition engines under nearly all engine operating conditions combustion pressure vibration is generated just after ignition. As a result of many experimental investigations the true nature for the cause of this interesting phenomenon was found and are listed: (1) This phenomenon probably originates from the extremely high local rate of burning of the hydrogen-air mixture. (2) Accompaning the stronger combustion pressure vibration was an increase in engine vibration and noise with increase in NOx emission and higher piston temperature. (3) Longer ignition delay resulted in a steeper pressure-time diagram which resalted in a stronger combustion pressure vibration. (4) The phenomenon had negligible effect on engine performance. (5) The phenomenon can be prevented by premixing a ceratain quantity of hydrogen gas into the intake air stream. The result was a shortened ignition delay.

The combustion processes in the prechamber and the main chamber of a small indirect injection (I.D.I.) diesel engine were observed simultaneously by high-speed photography. These observations made it possible to characterize the behavior of flames in both chambers, that is, ignition of fuel, developing and rotating flames in the prechamber, and a flame jet spouting into the main chamber. The effect of engine variables, such as fuel injection timing, cross-sectional area of a throat, fuel injector location, and a recess in a piston top, on the combustion process as well as the engine performance were considered. A flame jet spouting into the main chamber separated into two directions and induced two vortexes. Brown sooty flames appeared along the prechamber wall and inside the flame jet which struck on the piston top. The higher-velocity flame jet and the two Intense vortexes induced by the flame jet realized superior fuel consumption and lower smoke emission.

The combustion process in spark-ignition engines can vary considerably cycle by cycle, which may result in unstable engine operation. The phenomena amplify in natural gas (NG) spark-ignition (SI) engines due to the lower NG laminar flame speed compared to gasoline, and more so under lean burn conditions. The main goal of this study was to investigate the main sources and the characteristics of the cycle-by-cycle variation in heavy-duty compression ignition (CI) engines converted to NG SI operation. The experiments were conducted in a single-cylinder optically-accessible CI engine with a flat bowl-in piston that was converted to NG SI. The engine was operated at medium load under lean operating conditions, using pure methane as a natural gas surrogate. The CI to SI conversion was made through the addition of a low-pressure NG injector in the intake manifold and of a NG spark plug in place of the diesel injector.

Two peristaltic pumps were tested to determine their accuracies in metering three liquid herbicides for injection-type sprayers. To maintain acceptable chemical application accuracy from either pump, recalibration is necessary if the formulation or its temperature changes. An experimental thermal flowmeter was developed and evaluated along with turbine and piston flowmeters. The piston flowmeter had the best linearity and smallest time constant. A system to control the flow rate of the injected chemical is proposed and was simulated to determine its dynamic response. The proposed chemical metering system, coupled with plumbing systems of sprayers used by private and commercial applicators, were simulated to predict chemical application accuracies.

Chrysler Corporation has developed an 8.0-liter engine for light truck applications. Numerous features combine to produce the highest power and torque ratings of any gasoline-fueled light truck engine currently available while also providing commensurate durability. These features include: a deep-skirt ten-cylinder 90° “V” block, a Helmholtz resonator intake manifold that enhances both low and mid-range torque, light die cast all-aluminum pistons for low vibration, a unique firing order for smooth operation, a “Y” block configuration for strength and durability, a heavy duty truck-type thermostat to control warm up, and a direct ignition system.

The widely accepted best practice for spark-ignition combustion is the four-valve pent-roof chamber using a central sparkplug and incorporating tumble flow during the intake event. The bulk tumble flow readily breaks up during the compression stroke to fine-scale turbulent kinetic energy desired for rapid, robust combustion. The natural gas engines used in medium- and heavy-truck applications would benefit from a similar, high-tumble pent-roof combustion chamber. However, these engines are invariably derived from their higher-volume diesel counterparts, and the production volumes are insufficient to justify the amount of modification required to incorporate a pent-roof system. The objective of this multi-dimensional computational study was to develop a combustion chamber addressing the objectives of a pent-roof chamber while maintaining the flat firedeck and vertical valve orientation of the diesel engine.

Increased options and flexibility in common rail direct injection provides a great opportunity for combustion optimization using fuel and air system with proper combustion chamber configuration. This paper elaborates the experimental work conducted for combustion optimization with combinations of piston bowl, intake port swirl, injector specifications and turbo charging on a 3.8 l four valve diesel engine of LDT application equipped with common rail fuel injection system and waste gate turbo charge. In meeting the target emission norms with internal engine measures, the design of the piston bowl and the nozzle configuration perform a defining role. Through simulations the best option had been carried out parametrically investigate the influence of piston bowl geometry and nozzle characteristics on the performance of the combustion system.

The paper presents a numerical investigation, aimed to explore the potential of 2-stroke Diesel engines, able to meet Euro VI requirements, for application to medium size commercial vehicles (power rate: 80 kW at 2600 rpm, max. torque 420 Nm from 1200 to 1400 rpm). The study is based on experimental performance of a highly developed 4-stroke engine. Two different designs are considered: Loop and Uniflow scavenging, the latter obtained through an opposed piston configuration. In both cases, no poppet valves are used, and the lubrication is provided by a 4-stroke-like oil sump. The study started with the development of a 4-stroke EURO VI engine, on the basis of a previous EURO IV version. A prototype of the new engine (named 430) was built and tested.

A master piston assembly has been developed for a heavy duty diesel engine compression brake to reduce sliding wear at an oil lubricated bearing steel counterface. The assembly, consisting of a medium carbon steel piston body and mechanically retained silicon nitride ceramic pad, is an economical alternative to a one piece tool steel piston.

The paper presents a new computer based design method for valve plate design using the simulation program CASPAR and the extension tool AVAS. CASPAR is based on a non-isothermal gap flow model considering time dependent gap heights and surface deformations due to high pressure loads for all connected gaps of swash plate axial piston machines. Among others the program allows the prediction of oscillating forces exerted on machine parts and the calculation of effective flow pulsation on both ports as a function of design and operating parameters. Together with the calculated instantaneous cylinder pressure the flow pulsation and oscillating forces can be taken as criterion to evaluate the effectiveness of design measures for noise reduction during the design phase, i.e. before prototype production. The models used in the program have been verified by different measurements on pumps and motors.

A hybrid (hydrostatic and hydrodynamic) model applicable to thrust bearing and hydraulic machine port plate is presented here. The model is based on Reynolds equation and variable viscosity effect is considered. Assumptions made are listed. Regardless of the assumptions, the model agrees with experimental results and can be used with minor restrictions for new hydraulic machines' and bearing design. Balance factor as a function of speed of rotation, gap height, barrel inclination and fluid viscosity is presented. The variable viscosity effect makes analysis more accurate for certain conditions when port plates' failures are likely.

This paper reviews application of D-Cycle technology to compact tractor diesel engine for improving efficiency & power. The study considers design challenges that are presented for accommodating D-Cycle technology in engine. The paper also covers resolving those challenges with established technical solutions. The study focuses on modifying conventional compact 4-stroke diesel engine with the intention of keeping design changes to a minimum level for incorporating differential stroke technology. Designing of vertically splitting lightweight piston crown which can be smoothly engaged and separated from main piston body without any impact, stem rod which connects piston crown with rocker arm, split connecting rod and rocker arm which is actuated by extra actuating camshaft in addition of present valvetrain camshaft, are covered. Lubrication of additional actuating camshaft is done by extending existing oil galleries.

Some new results of the theoretical work with the heat regeneration within the internal combustion piston engines are presented in this paper. A new construction of such an engine including better balancing of mass forces is proposed as well. The construction of its process unit makes possible the prolonged expansion alone and together with the heat regeneration which in turn result in better efficiency of processes comparable with those in the conventional internal combustion engines.

Systems today are designed to be more flexible than ever before. This increasing demand has made electronically controlled systems more popular and brought into being a formal field called Mechatronics. The science of mechatronics uses mechanical, electrical, electronic, and computer science concepts in a single machine or system[1,6,8]. The key of mechatronics is that all of these areas are combined in the design stage. By using the ideas of mechatronics, more flexible and efficient machines can be produced. Electronically controlled systems are currently replacing the previous mechanically controlled systems[2,3,5].

This paper investigates the development of a deaeration device to remove nitrogen from the hydraulic fluid in hydraulic hybrid vehicles (HHVs). HHVs, which use accumulators to store and recycle energy, can significantly reduce vehicle emissions in urban delivery vehicles. In accumulators, nitrogen behind a piston cylinder or inside a bladder pressurizes an incompressible fluid. The permeation of the nitrogen through the rubber bladder into the hydraulic fluid limits the efficiency and reliability of the HHV system, since the pressure drop in the hydraulic fluid can in turn cause cavitation on pump components and excessive noise in the system. The nitrogen bubbles within the hydraulic fluid may be removed through the employment of commercial bubble eliminators if the bubbles are larger than a certain threshold. However, gas is also dissolved within the hydraulic fluid; therefore, novel design is necessary for effective deaeration in the fluid HHV circuit.