Search Results

The authors designed and produced a new dual fuel injector that allows two different kinds of fuel to be injected. This injector contains both a throttle type nozzle and a hole type which are located coaxially. The injection timing as well as the fuel quantity can be controlled individually. The running test using two lines of gas oil brought a good reduction of NOx and exhaust smoke. The experiment using gas oil and alcohol also brought a satisfactory reduction of exhaust emission.

Nozzles tip Temperature (NTT) of an injector is a critical parameter for an engine as far as reliability of engine is concerned. It is required to ensure that the injectors operate under its operational limit because higher operating temperatures would result in enlargement of the nozzle spray tip, resulting in higher through flow, producing more undesirable power. This could result in failure of other components in the engine. In this paper we identify the various parameters that are critical for NTT and thereby predict the NTT by having the known input parameters. Response surface methodology and artificial neural network are used to identify the parameters, estimate the significance of each parameter and predict the NTT. Based on this analysis, even without the use of an instrumented injector NTT can be predicted at various working conditions of the vehicle on different terrains.

Two factors contribute significantly to the widespread acceptance of a new technology in chemical application 1) simplicity 2) field ruggedness. In the past few years several new types of spray nozzles have been developed to meet the changing needs of applicators. Each is designed to meet specific performance criteria and thus has varying degrees of complexity. The wide angle full cone spray tip and the extended range flat spray tip are both well suited for uses with sprayer controllers. Each hydraulic spray tip has a wide range of operating pressures. The wide angle full cone tip produces large droplets in a full cone pattern. It is well suited for applications where drift control is essential. The nozzle maintains a 120° spray angle throughout a pressure range of 15 to 40 psi. The extended range flat spray tip provides excellent spray distribution at both low and high pressures unlike conventional flat spray tips.

The effect of pre-chamber volume and nozzle diameter on performance of pre-chamber ignition device in a heavy duty natural gas engine has previously been studied by the authors. From the analysis of recorded pre- and main chamber pressure traces, it was observed that a pre-chamber with a larger volume reduced flame development angle and combustion duration while at a given pre-chamber volume, smaller nozzle diameters provided better ignition in the main chamber. The structure of pre-chamber jet and its mixing characteristics with the main chamber charge are believed to play a vital role, and hence CFD simulations are performed to study the fluid dynamic aspects of interaction between the pre-chamber jet and main chamber charge during the period of flame development angle, i.e. before main chamber ignition. It has been observed that jets from a larger pre-chamber penetrates through the main chamber faster due to higher momentum and generates turbulence in the main chamber earlier.

Urea SCR is an established method to reduce NOx in dilute exhaust gas. The method is being used currently with stationary powerplants, and successful trials on motor vehicles have been conducted. The reason most often cited for rejecting urea SCR is lack of urea supply infrastructure, yet urea and other high nitrogen products are traded as commodities on the world market as a fertilizer grade, and an industrial grade is emerging. For a subset of commercial vehicles, urea can be provided by service personnel at designated terminals. But this approach does not support long distance carriers and personal use vehicles. The preferred delivery method is to add urea during vehicle refueling through a common fuel nozzle and fill pipe interface: urea / diesel co-fueling. Aqueous urea is well suited to delivery in this fashion.

Cold spray (CS) is a rapidly developing solid-state repair and coating process, wherein metal deposition is produced without significant heating or melting of metal powder. Solid state bonding of powder particles is produced by impact of high-velocity powder particles on a substrate. In CS process, metal powder particles typically of Aluminum or Copper are suspended in light weight carrier gas medium. Here high pressure and high temperature carrier gas is expanded through a converging-diverging nozzle to generate supersonic gas velocity at nozzle exit. The CS process typically uses Helium as the carrier gas due to its low molecular weight, but Helium gas is quite expensive. This warrants a need to explore alternate carrier gases to make the CS repair process more economical. Researchers are exploring another viable option of using pure Nitrogen as a carrier gas due to its significant cost benefits over Helium.

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.

This study involves the operation of the Common Rail Diesel Injection, atomization characteristics of fuel and reconditioning of diesel engine nozzles. The nozzles of the Common Rail system were repaired in order to give them optimum conditions of operation. For it be confirmed, the volume of Diesel injected was measured as a function of injection pressure, injection angle and the cone angle of the atomized fuel into new nozzles (control), used and reconditioned. In the evaluation of the volume, it was used a circuit consisting of a high pressure pump, a source of pulses and a reservoir of fuel oil. For the geometric characteristics of the fuel spray was used a high speed filming, 4000 frames per second, applying shadowgraphy techniques for measuring these angles. The experimental results allowed evaluating the types of changes in the nozzle after the reconditioning process.

The paper deals with the hydraulic phenomena and the dynamics of individual components of the conventional injection system pump-pipe-injection nozzle. It also describes in detail the influences of individual components upon the fuel injection process. The mathematical model featuring all these phenomena was simulated on the computer. To solve all the equations numerically we applied the Runge-Kutta IV method. The simulation results are compared with the results of extensive and elaborate investigations. The testing of the injection system was performed on a special test stand designed for testing injection systems. The measurements of the effective flow areas were carried out on a test stand specially adapted for testing injection nozzles and pumps. Moreover, the injection systems durability tests were also conducted on special test stands.

The pressure gain characteristics of jet pipe servovalve is required as an input to the designer for improving performance of the servovalve. An attempt has been made to design the first stage jet pipe servovalve parameters to get maximum pressure recovery. The static recovery pressure in receiving holes is a function of jet pipe nozzle displacement relative to receiver plate. The recovery pressure depends on web thickness, jet pipe nozzle diameter, receivers hole diameter, nozzle offset and nozzle stand-of distance. A detailed static recovery pressure analysis of a two stage, four-way, closed ports electrohydraulic flow control valve considering the effect of web thickness, nozzle diameter, receiver hole diameter and offset parameters are presented in the paper. Also the effect of supply pressure on recovery pressure is presented.

The diesel engine is still one of the most common and most efficient mobile energy converters. Nevertheless, it is troubled by many problems, one of them being nozzle coking. This is not a new problem; however, due to the introduction of more advanced injection systems and a more diverse fuel matrix, including biofuels, the problem has become more complex. The nozzle holes are also much narrower today than when the problem first appeared and are therefore more sensitive to coking. Two CEC sanctioned coking tests exist for diesel engines, but no universally accepted test for heavy duty engines. In this paper, tests have been performed with B10 doped with 1 ppm zinc on a single cylinder engine, based on a heavy duty engine, with the purpose to develop a simple accelerated coking test. To have relevance to real usage, the test was based on real engine load points from a high power Euro V engine calibration. The coking propensity was studied in an engine speed sweep at max load.

Cavitation is the major cause of the effective flow area reduction in fuel nozzles, together with mechanical damage, which leads to an increase of pressure losses. This paper describes the effect of different geometries along the fuel nozzle holes simulated with OpenFOAM® to control the cavitation and shape of the fuel jet. Previous work has only focused on the development trend towards conical spray holes that tapers towards the outlet with a strong rounded inlet edge, to increase the static pressure and thus reduce the cavitation tendency in nozzles; however, the jet forms a very narrow cone angle. The aim of this study is to evaluate the effect of constricted, expanded and gradually wider nozzles holes. The simulation reveals that the cavitation level can be changed and controlled depending on the geometry of the nozzle holes, the wider the inlet, the less is the cavitation; at the same time, the narrower the outlet, the better is the fuel atomization.

The liquid phase penetration of diesel sprays under reacting conditions is measured in an optical heavy-duty Direct Injection (DI) diesel engine. Hot gas reservoirs along the diffusion flames have previously been shown to affect the liftoff length on multi hole nozzles. The aim of this study is to see if they also affect the liquid length. The inter-jet spacing is varied together with the Top Dead Center density and the inlet temperature. To avoid unwanted interferences from the natural flame luminosity the illumination wavelength is blue shifted from the black body radiation spectrum and set to 448 nm. Filtered Mie scattered light from the fuel droplets is recorded with a high speed camera. The liquid fuel penetration is evaluated from the start of injection to the quasi steady phase of the jets. Knowledge of jet-jet interaction effects is of interest for transferring fundamental understanding from combustion vessels to practical engine applications.

The effect of increased clearance between the needle and its guides in a fuel injection nozzle on the rate of lacquer deposit formation from neat sunflower oil was investigated. Bosch fuel injection nozzles were tested on a fuel v injection calibration stand. The needle clearance reduction due to deposit buildup was monitored with a pneumatic leak test. Two test series of 100 hours duration each were performed at a temperature of 350°C. Each series consisted of ten 10-hour segments with a complete system shutdown after each segment. For the first test series the system was allowed to cool down before each shutdown. During the second test series the system was stopped while still hot. For fuels with physical and chemical properties similar to those of neat sunflower oil, excessive residue on the internal surfaces of the injection nozzles is likely to occur with the ultimate result of complete needle immobility.

The effects of a multi-hole nozzle with throttle construction (NTC) on combustion and emissions were investigated at high pressure fuel injection conditions. The throttle area was larger than the total injector hole area, therefore its fuel flow quantity was about the same as the standard nozzle under steady flow conditions. But the initial fuel injection rate was lower under unsteady flow conditions and smoke emissions were improved with the NTC. It is postulated that these effects were due to fuel flow turbulence inside the nozzle during the time of needle valve lift.

The effects of different shot peening parameters on the fatigue life of rear axle hypoid pinion gears were evaluated. Shot hardness, shot size, intensity, shot velocity and prior heat treatment were studied and compared to current production. Metallurgical analysis of the carburized SAE 4320 gears along with residual stress gradient analysis at tooth root fillets were performed. The results showed that significant fatigue life enhancement can be achieved by precision shot peening (directed, air nozzle type) and proper determination and tight tolerance of shot peening process parameters and heat treatment.

The feasibility of using exhaust temperatures and injector nozzle needle lift duration to predict power output and fuel consumption of a diesel engine was investigated using an instrumented John Deere 4440 tractor. Using data obtained during a series of PTO dynamometer experiments, regression models were determined correlating the needle lift duration, exhaust temperatures, and engine speed with the parameters of interest. The models were subsequently tested under normal tractor operating conditions on a commercial farm. Fuel flow and engine power output were accurately predicted from engine speed and needle lift duration and both these variables could be measured using one needle lift sensor. Engine power estimation from exhaust temperature measurements proved unsatisfactory due to the slow speed of response to changes in engine load.

Cyclic variability in internal combustion engines (ICEs) arises from multiple concurrent sources, many of which remain to be fully understood and controlled. This variability can, in turn, affect the behavior of the engine resulting in undesirable deviations from the expected operating conditions and performance. Shot-to-shot variation during the fuel injection process is strongly suspected of being a source of cyclic variability. This study focuses on the shot-to-shot variability of injector needle motion and its influence on the internal nozzle flow behavior using diesel fuel. High-speed x-ray imaging techniques have been used to extract high-resolution injector geometry images of the sac, orifices, and needle tip that allowed the true dynamics of the needle motion to emerge. These measurements showed high repeatability in the needle lift profile across multiple injection events, while the needle radial displacement was characterized by a much higher degree of randomness.

In order to unify the boundary conditions for various pipe elements and to simplify the computer code, the one-dimensional boundary conditions for three-way junction are extended to those for some pipe elements such as a nozzle and an elbow. To examine whether the extended boundary conditions are useful or not, the pulsatile flow through the pipe with the nozzle or elbow are numerically simulated using a Random-Choice Method and then the results are compared with those by the experiments. As a result, good agreement was found between experiments and calculations as long as the pressure histories are concerned and the extension of the boundary conditions is found to be valuable.

As a key component of airstream system equipped in the road sweeper, the structure of the suction nozzle determines its internal flow field distribution, which affects the dust-sucking efficiency to a great degree. This research is aiming to determine a better suction nozzle structure. Starting with an analysis of the one used in a certain type of road sweeper, the initial model of the suction nozzle is established, and the internal flow field is simulated with typical computational fluid dynamics (CFD) software named FLUENT. Based on the simulation results, the dust-sucking capability of the initial structure is evaluated from the aspects of pressure and velocity distribution. Furthermore, in order to explore the influence of different structural parameters on the flow field distribution within the suction nozzle, models with different cavity heights and shoulder angles are established, and Univariate Method is utilized to analyze the contrast models.