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Vapor phase lubrication has been investigated as a method of lubricating the piston ring/liner interface of low heat rejection engines. Tests were run in a single cylinder engine which contained several ceramic components. One test was run with vapor phase lubrication using tricresyl phosphate and the second test was run with no intentional lubrication. The wear coefficients for the vapor phase lubrication piston ring and liner were reduced by 52% and 72%, respectively, compared to those obtained with no intentional lubrication. The wear coefficients produced using vapor phase lubrication were two orders of magnitude greater than those produced in conventional diesel engines.

Delivery of a lubricant as a vapor mixed with a carrier gas provides a method of controlling the delivery rate of the lubricant. Temperatures in the range of 370 to 800 C are high enough to produce a lubricating film from tricresyl phosphate [TCP] vapor delivered in nitrogen as a carrier gas. The solid film lubricant formed by this delivery system provides excellent lubrication for a four-ball wear tester run at 370 °C. Deposit rates are compared for TCP vapor delivered lubrication over a temperature range using stainless steel and quartz surfaces. The deposit rate is sensitive to TCP concentration in the carrier gas. The deposit rates of the TCP decomposition products versus time are reported. Having been demonstrated in laboratory tests, the Vapor Phase [VP] concept is being pursued for hot section lubrication of the advanced (low heat rejection) diesel engines.

The impingement of liquid fuel onto the surfaces of the combustion chamber (wall-wetting) has been shown to be an important source of HC emissions from direct-injected SI engines, and can even result in pool fires and diffusion flames. Some degree of wall wetting, particularly on the piston top, is believed to occur in every current DIG engine design, but the behavior of the wall-bound fuel throughout the engine cycle is poorly understood. The goal of this study was to gain a better understanding of the fundamental interaction between liquid fuel droplets and the piston under engine-like conditions, by observing the vaporization of individual fuel drops as the surface temperature and ambient pressures were varied in a controlled environment. The vaporization of several single-component fuels, binary mixtures, and multi-component fuels was examined in the range of surface temperatures between 50 and 300 °C and ambient pressures between 50 and 1270 kPa (abs).

The report quantifies regional and seasonal variations in the composition, chemical and physical properties of natural gas in Brazil over a five-years time period (1992-96), corresponding to approximately 2,200 gas analyses. These data are intended to provide a strong statistical basis for understanding the properties of natural gas in support of engine and vehicle manufacturers making equipment design and development decisions reciprocating engine technology and natural gas composition standards.

Automatic variation of internal combustion engine valve timing in response to load and speed is an effective technique for reducing emission of oxides of nitrogen and unburned hydrocarbons. The variation employed is cam advance, which causes part of the exhaust gases normally expelled near the end of the exhaust stroke to be retained and mixed with the fresh air-fuel mixture during the following inlet stroke. Part of the unburned hydrocarbons normally emitted are contained in these recirculated end-of-stroke gases, and are oxidized further by re-exposure to combustion. The peak flame temperature is reduced by the diluent, and formation of oxides of nitrogen is suppressed. A prototype vehicle equipped with an automatic cam advance system shows that emissions measured by the Federal Test Procedure are reduced by the following amounts: nitric oxide 64%, unburned hydrocarbons 32%, and carbon monoxide 16.5%.

This paper traces the historical development of the BICERI variable compression ratio piston and its use in a number of engines. In early petrol experiments a variable compression piston covering the range from 6.5:1 to 16.5:1 showed significant efficiency improvements on 70 octane petrol. In the diesel engine field, Teledyne Continental increased the power of a V12 direct injection tank engine from 550 hp (30 hp per litre) to 1475hp (80 hp per litre) retaining the original crankcase and structure. At BICERI the output of a supercharged research engine was increased to 40 bar bmep with a peak cylinder pressure of only 165 bar. Military application lapsed with the preference for gas turbine engines, but the time is now right to explore the capabilities of variable compression within the wider automotive scene. Volkswagen have been working on a variable compression engine and have shown fuel consumption improvements up to 13% together with lower emissions.

Variable compression ratio (VCR) technology has long been recognized as a method for improving the automobile engine performance, efficiency, fuel economy with reduced emission. This paper presents a design of hydraulically actuated piston based on the VCR piston proposed by the British Internal Combustion Engine Research Institute (BICERI). In this design, the compression height of the piston automatically changes in response to engine cylinder pressure by controlling the lubrication oil flow via valves in the piston. In addition, numerical models including piston kinetic model, oil hydraulic model, compression ratio model and etc., have been established to evaluate the piston properties. The oil flow characteristics between two chambers in VCR piston have been investigated and the response behaviors of VCR engine and normal engine, such as compression pressure and peak cylinder pressure, are compared at different engine loads.

The complicated In-cylinder varying density field behavior of gaseous fuels makes the air fuel mixing process difficult to study. This problem urges to find out the injected gaseous fuel density distribution. This paper tries to find out the normalized injected CNG density distribution at small injection pressure. Background oriented schlieren and image processing techniques are implemented to find the variable density distribution on a constant volume chamber during injection.

VPT (Variable Piston Timing) utilizes a lightweight piston design that varies the piston displacements and the periods of the 4 strokes, produces a power stroke in every revolution, and more. VPT can incorporate electronic devices by on board computer to change the stroke ratios and the timing during engine operation. This article discusses VPT retrofit of a slow speed engine without electronics. Substantial horsepower, torque and some efficiency gains are achieved. The hardware changes are kept to a minimum. The first engine is scheduled to be tested in the third quarter of 1997. Electronic VPT will be included in the next generation engine.

The Reactivity Controlled Compression Ignition concept for dual-fuel engines has multiple challenges of which some can be overcome using Variable Valve Actuation approaches. For various fuel combinations, the engine research community has shown that running dual-fuel engines in RCCI mode, improves thermal efficiency and results in ultra-low engine-out nitrous oxides and soot. However, stable RCCI combustion is limited to a certain load range, depending on available hardware. At low loads, the combustion efficiency can drop significantly, whereas at high loads, the maximum in-cylinder pressure can easily exceed the engine design limit. In this paper, three VVA measures to increase load range, improve combustion efficiency, and perform thermal management are presented. Simulation results are used to demonstrate the potential of these VVA measures for a heavy-duty engine running on natural gas and diesel.

In a Passive suspension, a shock absorber generates damping force by pressurizing the oil flow between chambers. Typically, vehicle responds with suspension deflection, which significantly depends on damping forces and suspension velocity. Tuning dampers for various roads and steering input is an iterative balancing process. In any setting, damping force w.r.t velocity is tuned for optimum ride and handling performance. Practically, to achieve a balance between the two is a tedious task as the choices & arrangements of inner parts like piston, port, valve etc., which defines the forces set up [soft / hard] are almost infinite. The objective of this paper is to measure, objectify and evaluate the performance of two such optimum setting in various ride and handling events. A passenger car set up with an optimum soft & hard suspension damping force is studied for various ride and handling sub-attributes and their conflicts are examined in detail from a performance point of view:

Exhaust-gas recirculation (EGR) causes the piston rings and cylinder liners of a Diesel engine to suffer abnormal wear on the sliding parts. The present study aimed at making clear such abnormal wear structurally by examining the state of lubrication of the piston with a floating liner method, observing directly a visualized cylinder and experimenting on a Diesel engine for wear. As a result, it was confirmed that soot in EGR gas would change a lot the characteristics of the piston friction force. There are two mechanisms: one directly enters the sliding surfaces, and the other enters the ring rear, applying more load to them. It was also confirmed that the level of wear on the piston ring would vary to a large extent as the state of lubrication changed.

This paper describes a measurement method using laser induced fluorescence we have developed for simple simultaneous measurements of piston ring oil film thickness at plural points for internal combustion engines. The findings obtained by the measurements of oil film thickness on both thrust and anti-thrust sides of the piston for a mono-cylinder compact diesel engine using this new measurement method are also discussed in this paper. One of main findings is that the oil film thickness of each ring on both sides differs markedly in terms of the absolute value and the stroke- to-stroke variation. It is found that this difference in oil film thickness is caused by the difference in the amount of lubricating oil supplied to the oil ring, and the effect is greater than that of engine speed or load.

A new method for rating the varnish of the piston skirt was developed by using image processing. The varnished area of a piston skirt was extracted from the developed color image in terms of the density and the color data. The figure of merit rating was calculated using a personal computer. The newly developed method makes it possible to rate varnish of the piston skirt automatically, quantitatively and quickly.

Mobile hydraulic equipment are today operated manually to a very large extent. There are, however, some applications where substantial benefits would be obtaind if some kind of feedback and more sophisticated control was used. One such application is the control of a crane. Usually the operator controlls the flow to each of the pistons so that the crane tip is moved in the desired direction (Fig. 1). Since many mobile hydraulic valves packages have electronic input and there exists built in position transducers for the pistons, it seems to be rather straightforward to introduce vector control of the crane tip directly. That is, the operator commands controlls the direction and speed of the crane tip. Here, a control algorithm is described that allows the use of mobile electrohydraulic proportional valves while still having accurate vector control of the crane tip.

Vegetable oils provide diesel engine performance similar to that obtained with diesel fuel, and this has been documented in many prior publications. Because they are potentially interchangeable with diesel fuel, interest has focused on vegetable oils as short-range alternate fuels. However, engine durability when burning vegetable oils may be adversely affected depending on the type of combustion system employed. Laboratory and field experimental tests have identified the prechamber engine as having the greatest short-range potential for using vegetable oil fuels. Performance and durability at low engine ratings are essentially the same as expected for operation on diesel fuel. However, at high engine ratings piston ring and cylinder liner wear are greater than expected for operation on diesel fuel.

Laboratory endurance tests were performed on a direct injected, turbocharged, and inter-cooled diesel engine. A 25/75 blend (v/v) of alkali refined sunflower oil with diesel fuel and a 25/75 blend (v/v) of high oleic safflower oil and diesel fuel were tested. For comparison prior to the tests with the experimental fuels, a baseline endurance run with Phillips D2 Reference Fuel was carried out. The major problems experienced while operating on the 25/75 blend of alkali-refined sunflower oil and diesel fuel were premature injection nozzle performance deterioration and heavier carbonaceous buildup in the compression ring grooves and on the piston lands. There was no significant problems with engine operation when using the 25/75 blend of high oleic safflower oil and diesel fuel. Based on the results of this investigation, the 25-75 blend of high oleic safflower oil with diesel fuel is a very promising candidate as an alternate fuel.

As a follow-up to our earlier paper[ 1 ]; we have evaluated the performance of a vegetable-based hydraulic oil, Mobil EAL 224H, in a series of Vickers piston pumps. The primary intent of this work was to address the oil life/oxidation stability and pump performance issues for vegetable-based hydraulic oils. Although we have over two years (1991-1993) of successful commercial experience with Mobil EAL 224H, we wanted to document the performance in a controlled set of experiments using a variety of piston pumps. Results demonstrate that although Mobil EAL 224H shows a substantial (25%) viscosity increase after approximately 1800 hours of operation at the maximum recommended temperature of 180°F, the pumps tested operate effectively within their respective industrial unit ratings.

The environmental implications of converting vehicles powered by Internal Combustion Engines (ICE) to battery powered and hybrid battery/ICE powered are evaluated for the case of Chile, one of the worldwide leaders in the production of lithium (Li) required for manufacturing of Li-ion batteries. The economic and environmental metrics were evaluated by techno-economic analysis (TEA) and Life Cycle Assessment (LCA) tools - SuperPro Designer and Gabi®/GREET® models. The system boundary includes both the renewable and nonrenewable energy sources available in Chile and well-to-pump energy consumptions and GHG emissions due to Li mining and Li-ion battery manufacturing. All the major input data required for TEA and LCA were generated using Autonomie vehicle modeling software. This study compares economic and environmental indicators of three vehicle models for the case of Chile including compact, mid-size, and a light duty truck.

Vehicle exhaust emissions measurements are reported for full-size panel vans operating on four alternative motor fuels and control gasoline. The emissions tests produced data on in-use vans. The vans were taken directly from commercial delivery service for testing as they accumulated mileage over a 24-month period. The alternative fuels tested were compressed natural gas, propane gas, California Phase 2 reformulated gasoline (RFG), and methanol (M-85 with 15 percent RFG). The control gasoline for the emissions tests was an industry average unleaded blend (RF-A). The vehicle technologies tested represent those options available in 1992 that were commercially available from Ford, Chrysler, and Chevrolet or which these manufacturers agreed to provide as test vans for daily use in commercial service by FedEx.