Search Results

The world is firmly focused on reducing energy consumption and on increasingly stringent regulations on CO2 emissions. Examples of regulatory changes include the new United States Environmental Protection Agency's (U.S. EPA) fuel economy test procedures which were required beginning with the 2008 model year for vehicles sold in the US market. These test procedures include testing at higher speeds, more aggressive acceleration and deceleration, and hot-weather and cold-temperature testing. These revised procedures are intended to provide an estimate that more accurately reflects what consumers will experience under real world driving conditions. The U.S.

Limited technical studies to speciate particulate matter (PM) emissions from gasoline fueled vehicles have indicated that the lubricating oil may play an important role. It is unclear, however, how this contribution changes with the condition of the lubricant over time. In this study, we hypothesize that the mileage accumulated on the lubricant will affect PM emissions, with a goal of identifying the point of lubricant mileage at which PM emissions are minimized or at least stabilized relative to fresh lubricant. This program tested two low-mileage Tier 2 gasoline vehicles at multiple lubricant mileage intervals ranging from zero to 5000 miles. The LA92 cycle was used for emissions testing. Non-oxygenated certification fuel and splash blended 10% and 20% ethanol blends were used as test fuels.

Since the sizes of the flywheel and clutch have been enlarged due to downsizing of diesel engines, the mass and moment of inertia at the crankshaft rear end have increased. Consequently, the serious bending stresses have appeared in the crankshaft rear. This paper describes the characteristics of those serious bending stresses, based on the mechanism for whirl resonance. The whirl resonance is largely impacted by the mass of the flywheel and clutch and by the distance from the crank-journal center of the rear end to the center of gravity of the flywheel and clutch.

Improving idle sound quality as well as reducing idle noise level is increasingly demanded for diesel engines. Therefore, unusual noise occurrence at idle is a serious problem, and the noise must be removed. This paper describes the characteristics and mechanism of ticking noise that is unusual noise radiated from the journal bearing of the camshaft at low idle speeds, based on the mechanism of cavitation in oil film existing between the journal and bearing.

Considerable development effort has shown that conventional diesel engine lubricating oil specifications do not define the needs for acceptable injector life in methanol-fueled, two-stroke cycle diesel engines. A cooperative program was undertaken to formulate an engine oil-fuel additive system which was aimed at improving performance with methanol fueling. The performance feature of greatest concern was injector tip plugging. A Taguchi matrix using a 100 hour engine test was designed around an engine oil formulation which had performed well in a 500 hour engine test using a simulated urban bus cycle. Parameters investigated included: detergent level and type, dispersant choice, and zinc dithiophosphate level. In addition, the influence of a supplemental fuel additive was assessed. Analysis of the Taguchi Matrix data shows the fuel additive to have the most dramatic beneficial influence on maintaining injector performance.

The operating conditions of a typical motorcycle are considerably different than those of a typical passenger car and thus require an oil capable of handling the unique demands. One primary difference, wet clutch lubrication, is already addressed by the current JASO four-stroke motorcycle engine oil specification (JASO T 903:2011). Another challenge for the oil is gear box lubrication, which may be addressed in part with the addition of a gear protection test in a future revision to the JASO specification. A third major difference between a motorcycle oil and passenger car oil is the more severe conditions an oil is subjected to within a motorcycle engine, due to higher temperatures, engine speeds and power densities. Scooters, utilizing a transmission not lubricated by the crankcase oil, also place higher demands on an engine oil, once again due to higher temperatures, engine speeds and power densities.

Increasingly stringent fuel economy and emissions regulations around the world have forced the further optimization of nearly all vehicle systems. Many technologies exist to improve fuel economy; however, only a smaller sub-set are commercially feasible due to the cost of implementation. One system that can provide a small but significant improvement in fuel economy is the lubrication system of an internal combustion engine. Benefits in fuel economy may be realized by the reduction of engine oil viscosity and the addition of friction modifying additives. In both cases, advanced engine oils allow for a reduction of engine friction. Because of differences in engine design and architecture, some engines respond more to changes in oil viscosity or friction modification than others. For example, an engine that is designed for an SAE 0W-16 oil may experience an increase in fuel economy if an SAE 0W-8 is used.

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.

This paper outlines the second part in a series on the effect of polymeric additives commonly known as viscosity modifiers (VM) or viscosity index improvers (VII) on gear oil efficiency and durability. The main role of the VM is to improve cold temperature lubrication and reduce the rate of viscosity reduction as the gear oil warms to operating temperature. However, in addition to improved operating efficiency across a broad temperature range compared to monograde fluids the VM can impart a number of other significant rheological improvements to the fluid [1]. This paper expands on the first paper in the series [2], covering further aspects in fluid efficiency, the effect of VM chemistry on these and their relationship to differences in hypoid and spur gear rig efficiency testing. Numerous VM chemistry types are available and the VM chemistry and shear stability is key to fluid efficiency and durability.

Using skirt-liner clearance and cylinder pressure measurements provided by Isuzu Motors, Ltd. of a production type gasoline automotive engine, a validation study was done of Ricardo's PISDYN code, which predicts the secondary motions and skirt liner elastohydrodynamic lubrication of pistons. Predictions using the computer code of the skirt liner clearance at two locations on the skirt were compared with measured results. Using the code, parametric studies were done. Very good qualitative and quantitative agreement was found for the baseline cases. In the parametric studies using the code only, the following were found: The predicted clearances were very sensitive to variation in cold minimum clearance. The effect of cylinder induced pressure deformation was significant, especially near the point of peak cylinder pressure. Increasing the cylinder pressure increased the peak clearances. Changing the asperity roughness height affected the clearances near a point of asperity contact only.

In order to clarify the characteristics of turbulence in diesel combustion, fluctuations of pressure and temperature were measured in a DI diesel engine, and the root mean square value, the auto-correlation coefficient and the power spectrum density of the measured fluctuations were analyzed comparing between the cases with and without pilot injection. The following concluding remarks are obtained. (1) The frequency power spectrum of in-cylinder pressure history is decreased by pilot injection in two frequency ranges from 0.2 to 2.0 kHz and from 2 to 5 kHz. (2) Fluctuation of combustion pressure is dependent on the maximum rate of pressure rise, which is dependent on ignition delay. (3) The maximum RMS of soot temperature fluctuation in the diffusion combustion is dependent on the maximum RMS of pressure fluctuation in the initial combustion. (4) Fluctuation of temperature during diffusion combustion period has the characteristics of isotropic turbulence.

Requirements to improve vehicle fuel economy continue to increase, spurred on by agreements such as the Kyoto Protocol. Lubricants can play a role in aiding fuel economy, as evidenced by the rise in the number of engine oil specifications that require fuel economy improvements. Part of this improvement is due to achieving suitable viscometric properties in the lubricant, but additional improvements can be made using friction modifier (FM) compounds. The use of FMs in lubricants is not new, with traditional approaches being oleochemical-based derivatives such as glycerol mono-oleate and molybdenum-based compounds. However, to achieve even greater improvements, new new friction modifying compounds are needed to help deliver the full potential required from next generation lubricants. This work looks at the potential improvements available from new FM technology over and above the traditional FM compounds.

Phosphorus is known to reduce effectiveness of the three-way catalysts (TWC) commonly used by automotive OEMs. This phenomenon is referred to as catalyst deactivation. The process occurs as zinc dialkyldithiophosphate (ZDDP) decomposes in an engine creating many phosphorus species, which eventually interact with the active sites of exhaust catalysts. This phosphorous comes from both oil consumption and volatilization. Novel low-volatility ZDDP is designed in such a way that the amounts of volatile phosphorus species are significantly reduced while their antiwear and antioxidant performances are maintained. A recent field trial conducted in New York City taxi cabs provided two sets of “aged” catalysts that had been exposed to GF-4-type formulations. The trial compared fluids formulated with conventional and low-volatility ZDDPs. Results of field test examination were reported in an earlier paper (1).

With the increasing use of modern, EGR-equipped, heavy-duty diesel engines and the use of lower sulfur and alternate fuels, such as biodiesel, lubricants are being exposed to a range of different compositions of acids. To complement the traditional detergent bases, todays lubricants have evolved to include a higher proportion of basic materials from amine-derived sources to aid in oxidation and soot control. This paper explores the impact of the different sources of acids, some of the issues they create and how they can be addressed, exemplified in a prototype CJ-4 lubricant formulation.

Ethanol-gasoline blends are widely understood to present certain technical challenges to engine operation. Despite widespread use of fuels ranging from E5 (5% ethanol in gasoline) in some European countries to E10 (10% ethanol) in the United States to E100 (100% ethanol; “alcool”) in Brazil, there are certain subjects which have only anecdotally been examined. This paper examines two such issues: the effect of ethanol on intake valve deposits (IVD) and the impact of fuel additive on filter plugging (a measure of solubility). The effect of ethanol on IVD is studied along two lines of investigation: the effect of E10 in a multi-fuel data set carried out in the BMW 318i used for EPA and CARB certification, and the effect of varying ethanol content from 0% to 85% in gasoline carried out in a modern flex-fuel vehicle.

Global original equipment manufacturers (OEMs) have requested lower viscosity automatic transmission fluid (ATF) for use in conventional and 6-speed automatic transmissions (AT) to meet growing demands for improved fuel economy. While lower-viscosity ATF may provide better fuel economy by reducing churning losses, other key performance attributes must be considered when formulating lower viscosity ATF(1,2). Gear and bearing performance can be key concerns with lower-viscosity ATFs due to reduced film thickness at the surfaces. Long-term anti-shudder performance is also needed to enable the aggressive use of controlled slip torque converter clutches that permit better fuel economy. And, friction characteristics need to be improved for higher clutch holding capacity and good clutch engagement performance. This paper covers the development of next-generation, low-viscosity ATF technology, which provides optimum fuel economy along with wear and friction durability.

The noise of diesel engines operating at low idle is an important noise evaluation criterion in both commercial vehicles and passenger cars. At low idle, a quiet, pleasant noise is required. Accordingly, unusual noise occurrence at low speed is a serious problem, and the noise must be prevented. In this paper, characteristics of the stick-slip noise, which is an unusual noise that radiates from the oil seal at low idle and the generating mechanism of the stick-slip noise in the six-cylinder-inline diesel engine are discussed. In addition, a method to prevent the stick-slip noise is presented.

A 100-hour engine dynamometer test for intake valve deposits (IVD) which uses a Ford 2.3L engine was developed by the Coordinating Research Council (CRC). Recently, this test has been approved by the American Society for Testing and Materials (ASTM) as Test Method D 6201-97. Since this test offers improvements in test variability, duration, and cost, it is expected to replace ASTM D 5500-94, a 16,000-km vehicle test run using a BMW 318i, as the key performance test for the Certification of Gasoline Deposit Control Additives by the EPA Final Rule. As a step in the replacement process, a correlation between valve deposit levels for the CRC 2.3L Ford IVD test and ASTM D 5500 BMW IVD test must be determined. This paper provides a statistical review of available data in an attempt to provide such a correlation.

This paper offers a brief explanation of Isuzu Transport Auto Control (I-TAC), a system used to accurately collect and control information in-transit. I-TAC was developed as a means to meet needs for transportation by truck.

Many marketers of branded diesel fuels are introducing a “premium” diesel fuel grade. The National Conference on Weights and Measures is recommending that one of the criteria for marketing a fuel as “premium” is that it have a lower cloud point or alternatively a reduced low temperature flow test (LTFT) failure point [1]. However, waxy crudes and process limitations make it difficult for refiners to economically make very low cloud point diesel fuel. Fortunately, cloud point depressants (CPDs) can overcome these limitations. However, refiners are concerned about the effect cloud point additives have on other diesel fuel properties. We found that cloud point depressants allow refiners to meet low temperature specifications while being neutral or beneficial to other diesel fuel properties.