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Parallel measurements of lubricant-film behavior and oil consumption in two identical small production IDI diesel engines are presented. Oil consumption was measured using tritium as a radioactive tracer, and instantaneous film thickness data between the piston and liner were obtained using laser fluorescence diagnostics. The data covered single- and multi-grade lubricants and five different ring configurations (two-piece vs three-piece rings at various ring tensions). The data illustrate (a) oil-film profiles under the rings, especially around the leading and trailing edges, (b) accumulation of oil on piston lands and skirt, (c) circumferential variations around the bore, (d) observations on ring rotation, and (e) the piston-skirt oil-pumping mechanism. Effects of lubricants and piston-ring configurations on oil-film characteristics are investigated, and the oil consumption data are compared with oil-film thickness measurements.

A preliminary study was done to select the more adequate composite material to be used as a reinforcement at the combustion bowl of higher output diesel engine pistons. From the three types of composites produced, namely, Ceramic Reinforced Material (CRM) , Metal Reinforced Material (MRM) and Fiber Reinforced Material (FRM) (1)*, FRM was selected after preliminary tests of mechanical properties, machinability and diesel engine tests, realized in a small monocylinder diesel engine.

The purpose of this work was to develop a high speed flow visualization system which could be used to observe the behavior of the air flow in a steady flow cylinder head assembly. This type of experimental rig has been used by engineers for many years to evaluate valve discharge coefficients. This study is believed to be the first high speed flow visualization of the air flow in a system of this type. Particular emphasis was placed on the characterization of intake generated swirl and tumble motions within the cylinder. A 40 watt copper vapor laser was used to expose motion picture films at 5000 frames per second. The light scattering medium was phenolic microballoons. Based on the flow visualization results, selected LDV measurements were made to quantify the visual observations. A propylene glycol aerosol was used for seeding in the LDV experiments.

The cylinder of the aluminum engine block without iron sleeve was coated directly with thin thermal barrier coatings of zirconia and chrome oxide. The cylinder head and valve face and the piston crown were also coated. These three engine components were tested individually and together. The fuel consumption performance of this 84 x 70 mm direct injection diesel engine improved 10% with only coated cylinder bore. When the fuel injection timing of the coated cylinder bore engine was retarded by about 2°CA, emissions characteristics were approximately the same level as for the baseline engine with 8% improvement in brake specific fuel consumption compared with the baseline engine. At constant fuel flow rate to the engine, the exhaust and cylinder head temperatures were higher for the insulated bore case. One can summarize the combustion temperature must have been higher and heat release rates were faster in the insulated case.

Continuous improvement of the NVH performance of current production powertrains is a necessary goal of domestic auto makers. In order to maintain a competitive product, it is necessary to re-evaluate proven hardware against demanding NVH performance targets established by the competition. This paper describes an NVH investigation of component modifications to the Ford 3.8 liter powertrain. The hardware investigated includes: ribbed and isolated rocker covers, drop-in roller fulcrums, forged steel and cast iron crankshafts, crankshaft bending damper, full skirt girdle, one piece bearing cap (bearing beam), reduced weight pistons and rods, ribbed sump, and alternate crank pulleys and water pump. At the conclusion of these investigations, a complete powertrain was assembled based on the recommendations generated in this project. The NVH features included in this “quiet” 3.8 liter engine and the rationale behind the decisions are described.

The paper describe investigations on the vibration characteristics of a gasoline engine due to piston slap and a diesel engine due to combustion. Engine parameters and vibration data were recorded and time series signals were obtained. The effect of speed, load and other engine parameters on vibration is investigated. Vibration due to piston slap is analysed with reference to major-minor thrust relationship, cylinder to cylinder variation, piston-slap force diagram and vibration-frequency curves. The experimental results suggest that all reciprocating engines would exhibit a complex vibration pattern due to piston slap at harmonic series of discrete frequencies, and the reason for this is analysed. The vibration transmitted by engine structure in response to the in-cylinder pressure development is termed here as ‘Vibration due to Combustion’ and is assessed from the spectrum of the Combustion Pressure curves and their derivatives in terms of time.

Aviation piston engine lubricating oils undergo extensive testing prior to their approval for use. During the revision of MIL-L-22851/J-1966 specifications, it was determined that a standardized engine test would be utilized. A Textron-Lycoming TIO-540-J2BD engine was selected as the engine for the 150-hour endurance test. Federal Aviation Regulation Part 33 served as the guideline for development of a standardized test specifically aimed at lubricating oil evaluation. This paper discusses this new 150-hour endurance test for piston engine lubricants used to gain SAE and MIL approval. This new test was conducted at the University of Illinois-Institute of Aviation during 1990.

In the early 1960's the U.S. Military began to gradually phase-out piston engined aircraft from it's inventory in favor of gas turbine powered aircraft. The emphasis of the aviation industry on the development of the new gas turbine engines and their attendant new synthetic lubricants resulted in the rapid decline of new oil development for aviation piston engines. As a result of this change in focus by the military and commercial engine builders, the maintenance of the MIL-L-6082 and MIL-L-22851 specifications also diminished. After years of decline, commercial interest in these specification products again developed. This paper is an attempt to document the rational used in modernizing these two specifications.

An improved human waste collection system was developed in 1985 using a piston and cylinder which collects, compacts, and stores in replaceable volumes human waste including cleaning material. Disposable pads on the piston face seal and clean the cylinder and occlusive air valves. Airflow provides waste entrainment and temporary retention. A series of prototypes including an automatic one-button operation unit was built and ground tested. A manually operated prototype with a number of test features including variable airflow was flown and evaluated on Shuttle flight STS-35. Performance was nominal. An airflow of 45 CFM (1.27 m3 min-1) was found to be adequate. Mean stowage volume of waste and hygienic material per use was 18.7 in3 (306cm3).

This paper outlines the design philosophy and evaluation of the new “H” series variable displacement, medium pressure, open-circuit, axial piston hydraulic pumps. The “H” series is based on previously existing, technically successful, rotating group designs, but has significant design improvements affecting the areas of: Unit Weight Envelope Size Ease of Assembly, Disassembly, Repairability and Modification Alternate Fluid Capabilities The “H” series is a family of naturally aspirated pumps nominally rated at 250 or 275 bar (3625 or 4000 psig), depending on system operating parameters. The geometric displacements of the four units in the series are as follows: 57cc (3.5 cu. in./rev.) 74cc (4.5 cu. in./rev.) 98cc (6.0 cu. in./rev.) 131cc (8.0 cu. in./rev.)

A mathematical model of an axial piston pump with a flapper-nozzle valve was developed. The first stage was dynamically stable, and calculated values of first-stage gain and dynamic response agreed well with experimental values. Linearized relations were produced for each component part and were combined to form the total state-variable representation of the model. The open loop system, the combined axial piston pump and flapper-nozzle valve, exhibited dynamic instability. However, when the feedback loop was augmented by the output pressure differential, stability was achieved. From the time responses of the augmented optimal control system, we observed that an increase of input current had little effect on the system response. Doubling the discharge flow rate doubled the overshoot, and an increase in the discharge volume slowed down the system responses. Increasing rotational speed of the pump produced a higher overshoot and a slower response.

The original spray model in the KIVA-II code includes sub-models for drop injection, breakup, coalescence, and evaporation. Despite the sophisticated structure of the model, predicted spray behavior is not in satisfactory agreement with experimental results. Some of the discrepancies are attributed to the lack of a fuel jet wall impingement sub-model, a wall fuel layer evaporation sub-model, and uncertainties related to the choice of submodels parameters. A spray impingement model based on earlier research has been modified and implemented in KIVA-II. Heat transfer between the fuel layer on the piston surface and the neighboring gaseous charge has also been modelled based on the Colburn Analogy. A series of two dimensional simulations have been performed for a Caterpillar 1Y540 diesel engine to investigate droplet penetration, impingement, fuel evaporation, and chemical reaction, and the dependence of predictions on certain model parameters.

It is still a new technique to produce series of hydraulic radial piston pump using integrated CAD/CAM technique. That is, a hydraulic pump could be produced according to the required NC format program in NC machine tool (NC post-processing). The program is automatically generalized after the design stage in a RPCADM package is over. The one of the highlights to use the integrated CAD/CAM technique is how to use the similitude theory as basic principles for the series design in the CAD stage. Another is the method of transferring detail drawing into required G-codes based on the G-codes bank which NC machine tools could follow to produce the part. The theory and method are explicated in this paper. And the NC format program (G-codes file) conducted from CAD is shown. A package for CAD/CAM of hydraulic radial piston pump is introduced briefly.

A natural gas engine oil must be designed and balanced in a proper way in order to be able to offer: excellent deposit control, superior oxidation and nitration control, extenden lubricant filter and engine life and reduced frecuency of shutdowns for main tenance. In order to choose a correct formulation, it was decidet to run a field tests where five differents low ash additive packages were tested. The selected engines are five WAUKESHA, model H2475, they are rated at 300 HP and are used for water pumping. The five engines were rebuilt before the beguining of the test. The liner diameters were measured, the same as the ring gaps. At the end of the test, that lasted 10.500 hs., the measurements were repeated and pistons and cranckases were inspected and calificated for deposit formation. Each 700 hours, a lubricant sample was analyzed for its main characteristics in order to evaluate its performance.

A pair of Caterpillar 3406B turbo charged diesel engines were converted to operate in a dual fuel mode installed in a small vehicle and passenger ferry and evaluated for performance for both diesel and natural gas operation. Full load power was achieved with dual fueling without knock. The “life” of the engines was extended from 15,000 marine hours to 30,000 marine hours (120,000 miles). This is equivalent to 600,000 miles and 1,200,000 miles in a road or truck application. Piston, piston rings, valve and bearing wear, was found to be significantly reduced and CO2 concentrations in the exhaust were also minimized. Lubricating oil life was also extended.

The hydraulic piston pumps that are used on off-highway vehicles create pressure pulsations that may generate excessive noise in the vehicle. The most effective method of reducing this noise is to decrease the amplitude of the pressure pulsations leaving the pump by using a reactive type of silencer. A reactive silencer changes the load impedance and reflects the pulsations back to the pump. This paper develops the insertion loss for a specific type of side branch resonator, called a cross-loop attenuator, and describes the design parameters that will result in the best insertion loss for a piston pump application.

The noise levels generated by a variable capacity axial piston pump and a fixed capacity axial piston motor have been measured using Sound Intensity techniques; no special acoustic test environment was employed. The experimental procedures followed, as closely as possible, draft International Standard ISO/DIS 9614-4. Because the machines were mounted on existing test stands it was found difficult to comply completely with the requirements laid down in the draft Standard. Typical test results are presented showing that pump overall Sound Pressure levels increase significantly with increasing delivery pressure. The effect of discharge pipe length on pump noise levels is relatively small. From the motor noise tests, it was found that variations in speed were much more important than load. The work has highlighted the need for the development of Sound Intensity procedures specifically concerned with fluid power pumps and motors.

Alcoa - Massena Operations is a totally integrated aluminum producer from primary production to fabricated rod, wire and bar products. Alcoa - Massena Operations currently offers sixteen different alloys of forging stock; eight of these have a wide usage in a variety of aerospace applications. Alcoa - Massena Operations can offer both O (annealed) and F (as-fabricated) tempers in both Class I and Class II product forms. Class II forging stock offers two to ten times tighter tolerances from a diameter standpoint than those of Class I. Available alloys now include 2219 and 2618 designed for high-temperature use and 4032 alloy for high-temperature wear performance (e.g. aircraft pistons). Alloy 7475 is also available, it offers microstructural control to provide superior fracture toughness properties. Details concerning structure-property relationships and overall facility support to these products and their respective applications will be presented.

In this paper, to reveal behavior of SO2 gas which is recirculated from the exhaust gas on wear of piston rings and cylinder liner in diesel engines, a numerical model to estimate the amount of SO2 in oil layer on the cylinder wall is developed. The experimental fact that increase of wear of the piston rings and the cylinder liner due to EGR can be explained by the increase of the calculated SO2 concentration in the oil layer.

A CAD/CAE procedure has been used for the analysis of the flow in an intake port-valve-cylinder assembly of a DI Diesel engine. The flow was simulated for both, steady state conditions and transient motored situation during intake and compression strokes. The characteristics of the helical port are analyzed, for the steady state case, in terms flow rate, generation of angular momentum flux and induced in-cylinder flow motion. The results of the simulation were correlated with experimental results, consisting of oil film visualizations on valve and intake port surfaces, and of local velocity measurements in the cylinder. The transient flow simulation shows the different characteristics of the flow motion in cylinder and piston bowl during intake and compression strokes. It was observed that the swirl generating capacity of the valve is different between the valve opening and closing phases.