Search Results

The US Army is currently assessing the feasibility and defining the requirements of a Single Common Powertrain Lubricant (SCPL). This new lubricant would consist of an all-season (arctic to desert), fuel-efficient, multifunctional powertrain fluid with extended drain capabilities. As a developmental starting point, diesel engine testing has been conducted using the current MIL-PRF-46167D arctic engine oil at high temperature conditions representative of desert operation. Testing has been completed using three high density military engines: the General Engine Products 6.5L(T) engine, the Caterpillar C7, and the Detroit Diesel Series 60. Tests were conducted following two standard military testing cycles; the 210 hr Tactical Wheeled Vehicle Cycle, and the 400 hr NATO Hardware Endurance Cycle. Modifications were made to both testing procedures to more closely replicate the operation of the engine in desert-like conditions.

Downsizing is an important concept to reduce fuel consumption as well as emissions of spark ignition engines. Engine displacement is reduced in order to shift operating points from lower part load into regions of the operating map with higher efficiency and thus lower specific fuel consumption [ 1 ]. Since maximum power in full load operation decreases due to the reduction of displacement, engines are boosted (turbocharging or supercharging), which leads to a higher specific loading of the engines. Hence, a new combustion phenomenon has been observed at high loads and low engine speed and is referred to as Low-Speed Pre-Ignition or LSPI. In cycles with LSPI, the air/fuel mixture is ignited prior to the spark which results in the initial flame propagation quickly transforming into heavy engine knock. Very high pressure rise rates and peak cylinder pressures could exceed design pressure limits, which in turn could lead to degradation of the engine.

The spark ignition (SI) engine has been known to exhibit several different abnormal combustion phenomena, such as knock or pre-ignition, which have been addressed with improved engine design or control schemes. However, in highly boosted SI engines, Low-Speed Pre-Ignition (LSPI), a pre-ignition event typically followed by heavy knock, has developed into a topic of major interest due to its potential for engine damage. Previous experiments associated increases in hydrocarbon emissions with the blowdown event of an LSPI cycle [1]. Also, the same experiments showed that there was a dependency of the LSPI activity on fuel and/or lubricant compositions [1]. Based on these findings it was hypothesized that accumulated hydrocarbons play a role in LSPI and are consumed during LSPI events. A potential source for accumulated HC is the top land piston crevice.

Lubricating oil affects the performance of friction materials in transmission, steering and brake systems. The TO-2 Test measured friction retention characteristics of lubricating oils used with sintered bronze friction discs. This paper introduces a new friction performance test for drive train lubricants that will be used to support Caterpillar's new transmission and drive train fluid requirements, TO-4, which measures static and dynamic friction, wear, and energy capacity for six friction materials, and replaces the TO-2 test. The new test device to be introduced is an oil cooled, single-faced clutch in the Link Engineering Co. M1158 Oil/Friction Test Machine.

The use of biodiesel requires the development of proper quantification procedures for biodiesel content in blends and in lubricants (fuel dilution in oil). Although the ester carbonyl stretch at 1746 wavenumbers (cm-1) is the most prominent band in the IR spectrum of biodiesel, it is difficult to use for quantification purposes due to a severe fluctuation of absorption strength from sample to sample, even at the same biodiesel content. We have demonstrated that the ester carbonyl fluctuation is not caused by variation in the ester alkyl chain length; but is most likely caused by the degree of hydrogen bonding of the ester functional group with water in the sample. Water molecules can form complexes with the ester compound affecting the strength of the ester carbonyl band. The impact of water on quantification of the biodiesel content of blends was significant, even for B100 samples that met the proposed ASTM D6751 water limit of 500 ppm by D6304 (Karl Fischer Methdod).

The performance and efficiency of spark ignited gasoline engines is often limited by end-gas knock. In particular, when operating the engine at high loads, combustion phasing is retarded to prevent knock, resulting in a significant reduction of engine efficiency. Since the invention of the spark ignition (SI) engine, much work has been devoted to improve and regulate fuel characteristics, such as octane number, to suppress engine knock. The auto-ignition tendency of the engine lubricant however, as described by cetane number (CN), has received little attention, as it has been assumed that engine lubricant effects on knock are insignificant, primarily due to low levels of average oil consumption. However, with modern SI engines being developed to operate at higher loads and closer to knock limits, the reactivity of engine lubricants can impact the knock behavior.

Fuel economy is not an absolute attribute, but is highly dependent on the method used to evaluate it. In this work, two test methods are used to evaluate the differences in fuel economy brought about by changes in engine oil viscosity grade and additive chemistry. The two test methods include a chassis dynamometer vehicle test and an engine dynamometer test. The vehicle testing was conducted using the Federal Test Procedure (FTP) testing protocol while the engine dynamometer test uses the proposed American Society for Testing and Materials (ASTM) Sequence VIE fuel economy improvement 1 (FEI1) testing methodology. In an effort to improve agreement between the two testing methods, the same model engine was used in both test methods, the General Motors (GM) 3.6 L V6 (used in the 2012 model year Chevrolet™ Malibu™ engine). Within the lubricant industry, this choice of engine is reinforced because it has been selected for use in the proposed Sequence VIE fuel economy test.

A head gasket is a component that sits between the engine block/liner and cylinder head(s) in an internal combustion engine. Its purpose is to seal high pressure combustion gasses in the cylinders and to seal coolant and engine oil. It is the most critical sealing application in an engine. As a general practice, the load deflection(L/D) characteristic is generated by the gasket manufacturer for edge molded or composite gasket types. However, in the case of a solid-sheet metallic gasket, where the gasket is expected to undergo localized yielding to provide adequate conformance and sealing, usually supplier may not be able to provide the required L/D curve due to difficulties to experimentally separate the large loads and small displacements from the elastic loads and deflections of the experimental apparatus. In absence of L/D curve, the typical analysis approach is to model gasket as 3D continuum elements available in ansys by considering nonlinear material and frictional contacts.

Despite the recent increase in fuel prices, the multi-billion dollar recreational boating market in North America continues to experience solid momentum and growth. In the U.S. economy alone, sales of recreational boats continue to increase with over 17 million boats sold in 2004 [1]. Of that share, outboard boats and the engines that power them, accounted for nearly half of all boat sales. Though there has been a shift in outboard technology to four-stroke cycle engines, a significant number of new engine sales represent two-stroke cycle engines employing direct fuel injection as a means to meet emissions regulations. With the life span of modern outboards estimated to be 8 to 10 years, a significant base of two-stroke cycle engines exist in the market place, and will continue to do so for the foreseeable future.

A solid particle sampling system (SPSS) that is equipped with a heated oxidation catalyst, micro-dilution tunnels, filter holders and sampling probes, was designed and developed to collect filter-based solid and total (solid plus volatile) particles from the exhaust of internal combustion engines, and to facilitate the measurement of solid and total particles when equipped with particle measuring instruments for size, number, mass, and other particle characteristics. The SPSS was characterized with laboratory aerosol and showed a very low solid particle loss of less than 5 percent using sodium chloride particles, very high volatile particle removal of better than 98 percent using oil droplets, and no formation of sulfuric acid particles when using ammonium sulfate particles. The SPSS is a useful tool for researchers interested in characterizing the solid and volatile fraction of particles emitted from combustion sources.

The US Army is currently seeking to reduce fuel consumption by utilizing fuel efficient lubricants in its ground vehicle fleet. An additional desire is for a lubricant which would consist of an all-season (arctic to desert), fuel efficient, multifunctional Single Common Powertrain Lubricant (SCPL) with extended drain capabilities. To quantify the fuel efficiency impact of a SCPL type fluid in the engine and transmission, current MIL-PRF-46167D arctic engine oil was used in place of MIL-PRF-2104G 15W-40 oil and SAE J1321 Fuel Consumption In-Service testing was conducted. Additionally, synthetic SAE 75W-140 gear oil was evaluated in the axles of the vehicles in place of an SAE J2360 80W-90 oil. The test vehicles used for the study were three M1083A1 5-Ton Cargo vehicles from the Family of Medium Tactical Vehicles (FMTV).

Sulfur containing species as well as other polar molecules provide lubricity and thermal stability to diesel fuels. During the refining process to produce low and ultra-low sulfur diesel fuels, these components are removed. As a result, fuel additives such as lubricity agents and antioxidant may be added to protect fuel stability and prevent fuel pump wear. Some lubricity additives, such as dimer acids, resulted in fuel filter plugging. The plugging mechanism was related to the capability of aliphatic acids to form agglomeration by interactions with the overbased detergents, delivered into the fuel as oil contaminants. Other sources of acids, derived from thermal degradation, can lead to the same problem. In this study, individual lubricant additives were mixed in the fuel to form single- and dual-component systems. Levels of compatibility and amounts of interaction products were evaluated for individual solutions.

Sulfur poisoning from engine fuel and lube is one of the most recognizable degradation mechanisms of a NOx adsorber catalyst system for diesel emission reduction. Even with the availability of 15 ppm sulfur diesel fuel, NOx adsorber will be deactivated without an effective sulfur management. Two general pathways are currently being explored for sulfur management: (1) the use of a disposable SOx trap that can be replaced or rejuvenated offline periodically, and (2) the use of diesel fuel injection in the exhaust and high temperature de-sulfation approach to remove the sulfur poisons to recover the NOx trapping efficiency. The major concern of the de-sulfation process is the many prolonged high temperature rich cycles that catalyst will encounter during its useful life. It is shown that NOx adsorber catalyst suffers some loss of its trapping capacity upon high temperature lean-rich exposure.

Engine tests are widely used to measure the ability of lubricating oils to reduce fuel consumption through improved mechanical efficiency. Previous publications have correlated laboratory-scale tests with the well-established Sequence VI and VIA engine methods. The present paper uses a matrix of 66 oils to produce an empirical model for the recently developed Sequence VIB engine test. A smaller matrix of oils was available for correlation with Sequence VI and VIA results. The models combine a purposely-designed friction test with conventional measures of kinematic and high-temperature high-shear viscosity. Good correlation was obtained with the Sequence VI, VIA and VIB results, as well as each of the five stages in the Sequence VIB test. The effects of lubricant oxidation in the 96-hour FEI-2 portion of the Sequence VIB test were similar for each of the oils. As a result, good correlation was observed between FEI-1 and FEI-2 results from the VIB test.

The Partnership for a New Generation Vehicle (PNGV) has identified the compression-ignition, direct-injection (CIDI) engine as a promising technology in meeting the PNGV goal of 80 miles per gallon for a prototype mid-size sedan by 2004. Challenges remain in reducing the emission levels of the CIDI-engine to meet future emission standards. The objective of this project was to perform an initial screening of crank case lubricant contribution to regulated engine-out emissions, particularly when low particulate forming diesel fuel formulations are used. The test engine was the Mercedes-Benz OM611, the test oils were a mineral SAE 5W30, a synthetic (PAO based) SAE 5W30, and a synthetic (PAO based) SAE 15W50, and the test fuels were a California-like certification fuel and an alternative oxygenated diesel fuel.

Cabin air quality is of continuing importance [1]. Contamination of air with particulates or vapors has the potential of affecting the health of passengers and flight crew. Therefore, measures are required to maintain acceptable levels of cabin air quality. One potential source of cabin air contamination is lubricating oils used in the engines. Type II oils are required for the main engines, but Type I or Type II oils can be used for the APU, with Type I recommended by some engine manufacturers for its cold-start properties. Southwest Research Institutes (SwRI®) Department of Emissions Research used an internally developed analytical method called Direct Filter Injection/Gas Chromatograph (DFI/GC™) to analyze for volatile fractions of lubricating oil contaminants on Environmental Control System (ECS) components. Samples of two standard Type II aviation turbine lubricating oils were analyzed with the DFI/GC™ method and their spectra examined.

Chassis dynamometer tests are often used to determine vehicle fuel economy (FE). Since the entire vehicle is used, these methods are generally accepted to be more representative of ‘real-world’ conditions than engine dynamometer tests or small-scale bench tests. Unfortunately, evaluating vehicle fuel economy via this means introduces significant variability that can readily be mitigated with engine dynamometer and bench tests. Recently, improvements to controls and procedures have led to drastically improved test precision in chassis dynamometer testing. Described herein are chassis dynamometer results from five fully formulated engine oils (utilizing improved testing protocols on the Federal Test Procedure (FTP-75) and Highway Fuel Economy Test (HwFET) cycles) which not only show statistically significant FE changes across viscosity grades but also meaningful FE differentiation within a viscosity grade where additive systems have been modified.

The study described in this paper covers the development of the Sequence IVB low-temperature valvetrain wear test as a replacement test platform for the existing ASTM D6891 Sequence IVA for the new engine oil category, ILSAC GF-6. The Sequence IVB Test uses a Toyota engine with dual overhead camshafts, direct-acting mechanical lifter valvetrain system. The original intent for the new test was to be a direct replacement for the Sequence IVA. Due to inherent differences in valvetrain system design between the Sequence IVA and IVB engines, it was necessary to alter existing test conditions to ensure adequate wear was produced on the valvetrain components to allow discrimination among the different lubricant formulations. A variety of test conditions and wear parameters were evaluated in the test development. Radioactive tracer technique (RATT) was used to determine the wear response of the test platform to various test conditions.

Semi-volatile organic compounds (SVOC) are a group of compounds in engine exhaust that either form during combustion or are part of the fuel and lubricating oil. Since these compounds occur at very low concentrations in diesel engine exhaust, the methods for sampling, handling, and analyzing these compounds are critical to obtaining good results. An improved dilute exhaust sampling method was used for sampling and analyzing SVOC in engine exhaust, and this method was performed during transient engine operation. A total of 22 different SVOC were measured using a 2012 medium-duty diesel engine. This engine was equipped with a stock diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction (SCR) catalyst in series. Exhaust concentrations for SVOC were compared both with and without exhaust aftertreatment. Concentrations for the engine-out SVOC were significantly higher than with the aftertreatment present.

The aim of the present work is to provide further guidance into better understanding the production mechanisms of soot emissions in Spark-Ignition SI engines fueled with compressed natural gas. In particular, extensive experimental investigations were designed with the aim to isolate the contribution of the fuel from that of lubricant oil to particle emissions. This because the common thought is that particulate emerging from the engine derives mainly from fuel, otherwise the contribute of lubricant oil cannot be neglected or underestimated, especially when the fuel itself produces low levels of soot emissions, such as in the case of premixed natural gas. The fuel-derived contribution was studied by analyzing the influence that natural gas composition has on soot emitted from a single cylinder Spark-Ignition (SI) engine. To achieve this purpose, methane/propane mixtures were realized and injected into the intake manifold of a Single-Cylinder SI engine.