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Fluoroelastmers are well known for their resistance to heat and fluids, and have become major material for crankcase oil seals. On the other hand, new additive formulations are developed for engine lubricants used for fuel economic gasoline engines. In this paper, the effects of those additives on properties of fluoroelastmers are investigated. The results of the immersion tests of both test plaques and oil seal products indicate that dithiocarbamates, friction modifier, have hardening effects on fluoroelastmers. The fluoroelastmer deterioration mechanism is determined by analysis of elastmer samples after immersion in oil.

The study of oil emission is of essential interest for the engine development of modern cars, as well as for the understanding of hydrocarbon emissions especially during cold start conditions. A laser mass spectrometer has been used to measure single aromatic hydrocarbons in unconditioned exhaust gas of a H2-fueled engine at stationary and transient motor operation. These compounds represent unburned oil constituents. The measurements were accompanied by FID and GC-FID measurements of hydrocarbons which represent the burned oil constituents. The total oil consumption has been determined by measuring the oil sampled by freezing and weighing. It has been concluded that only 10 % of the oil consumption via exhaust gas has burned in the cylinders. A correlation of the emission of single oil-based components at ppb level detected with the laser mass spectrometer to the total motor oil emission has been found.

The purpose of this study is to analyze con-rod bearing lubrication under reduced oil supply rate conditions. An engine was modified to measure the oil supply rate to a con-rod big-end bearing. Then the effects of the oil supply rate on bearing temperatures and the contact between a journal and a bearing were investigated in order to analyze lubrication characteristics. The bearing temperatures increased in accordance with reduced oil supply rate. On the other hand, the contact frequency hardly changed under almost all conditions, but steeply increased near one-third of the standard oil supply rate at the highest speed of 5000 rpm in the experiments. The results show that the reduced oil supply rate decreases the cooling effect but the hydrodynamic lubrication was sufficiently achieved except the above-mentioned severe condition.

A fleet test study was initiated to compare the use of a unique boundary chemistry (UBC) containing PTFE engine treatment, as a supplement to a current 10W-30, API SJ/GF-2 motor oil, versus the use of the oil without any supplement. The test was conducted with a taxi fleet of 1998 Chrysler 2.4L minivans. The factory-fill oil was drained after 5 thousand km and the group of vehicles entered the test program designed as a double-blind study, wherein, neither the drivers nor analysts knew the identities of reference and treated engines. Half of the taxis received a one-time application of the engine treatment. Subsequent oil drain intervals were conducted every 6.5 thousand km so that at 11 thousand km a baseline and treated engine were pulled from the vans and sent to the laboratory for analysis. The rest of the fleet continued on to 50 thousand km, six oil changes later, when two more engines were obtained as before. The last data point was at the 82 thousand km mark.

The authors have utilized a modified engine with a transparent glass cylinder for motoring equipment. The effect of the top ring which has a special joint (triangle step joint) on the lubricating oil flow was examined. The results indicate that the lubricating oil flow is considerably reduced by utilizing the top ring with a special joint (triangle step joint) as compared to a standard joint (straight joint). We have also found that if the modified engine is operated with attention to the pressure difference between intake manifold and crankcase, or the positions of the piston ring gaps, the lubricating oil flow is reduced by utilizing a two piston ring set (where a top ring and an oil ring are set on a piston) with the top ring having a special joint and without the second ring as compared to a three piston ring set (where a top ring, a second ring and an oil ring are set on a piston) with the top ring having a standard joint and with the second ring.

In order to understand the relationship between the location of piston ring gap and instantaneous change of oil consumption during engine operation, the ring rotation and instantaneous oil consumption were measured simultaneously in a hydrogen fueled single cylinder spark ignition engine. A radioactive-tracer technique was used to measure the rotational movement of piston ring. Two kinds of isotopes(60Co and 192Ir) with different energy level were mounted to the top and 2nd rings to measure each ring's movement independently. The instantaneous oil consumption was obtained by analyzing CO2 concentration in exhaust gas. From the result of ring rotational movement, typical patterns of ring rotation were obtained as follows; Rotational movements are usually initiated by changing the operating conditions. Piston rings tend to rotate easily under low load condition. The rotation speed of ring usually ranged in 0.2∼0.4 rev/min for top ring and 0.5∼0.6 rev/min for 2nd ring.

This paper describes the results of a liquefied petroleum gas (LPG) fleet test conducted using para-transit, medium-duty vehicles. The vehicles were part of an active municipal fleet providing daily service on varying operating routes. Over a period of nine months, each vehicle was fueled with a series of butane/propane mixtures. The mixtures tested were HD5 LPG as the baseline fuel, 20 percent butane/80 percent propane, 30 percent butane/70 percent propane, and a final blend of 50 percent butane/50 percent propane by volume. The test vehicles showed improved fuel economy as the butane content increased in the fuel mixture, even without modification to existing LPG fuel systems. The improved fuel performance was consistent with the higher energy content of butane, compared to an equal volume of propane. The vehicles displayed no symptoms of performance or maintenance problems that would be related to operation of the fuel mixtures.

This publication represents tests on a new particulate trapping system based on metal fleece as the trapping medium. The tested trap system uses several traps of pleated, highly temperature-resistant metal fleece with parallel paths directly in the exhaust stream of the diesel engine. For the regeneration of the traps respectively one of the traps is separated from the exhaust stream by a rotary slide valve and brought up to the regeneration temperature through direct electrical heating of the metal fleece, so that the soot of the trap surface burns as a result of regeneration air being supplied. Based on the description of the trapping system, the tests on the test bench for determining the particulate separation rates are illustrated. In another test the regeneration of the traps, loaded before on the engine, was studied in a lab test. Here the optimal regeneration parameters and the degree of the secundary emissions of gaseous exhaust components was determined.

Particle concentrations and size distributions were measured in the exhaust of a turbocharged, aftercooled, direct-injection, Diesel engine equipped with a ceramic filter (trap). Measurements were performed both upstream and downstream of the filter using a two-stage, variable residence time, micro-dilution system, a condensation particle counter and a scanning mobility particle sizer set up to count and size particles in the 7-320 nm diameter range. Engine operating conditions of the ISO 11 Mode test were used. The engine out (upstream of filter) size distribution has a bimodal, log normal structure, consisting of a nuclei mode with a geometric number mean diameter, DGN, in the 10-30 nm range and an accumulation mode with DGN in the 50-80 nm range. The modal structure of the size distribution is less distinct downstream of the filter. Nearly all the particle number emissions come from the nuclei mode, are nanoparticles (Dp < 50nm), and are volatile.

The paper reports on a study performed as a joint project between Rhodia, Renault Automobiles and AVL and deals with the application of a sintered metal trap (SMT) whose regeneration is supported by the use of a Ce-based fuel-borne catalyst installed on a delivery van equipped with a conventional IDI/NA diesel engine. For demonstration purpose, a trap protection strategy was developed with the aim to minimize the trap loading and thus the consequent fuel consumption penalty that can be observed for worst-case low speed driving scenarios. Measures to temporarily increase the exhaust gas temperature during inner-city driving and therefore to initiate the start of regeneration were successfully applied. MAJOR EFFORT IS BEING currently undertaken to develop and apply advanced aftertreatment systems to meet future proposed exhaust gas emission standards for passenger cars, LDT and HD diesel engines.

Particulate matter in the air has become the focus of increased attention due to the concern of potential health effects. Among other sources, automotive vehicles are seen as a major contributor of fine particles. At present there is limited information available relating either to the number or size distribution of automotive particle emissions and detailed evidence has still to be established. To develop an understanding in the area of automotive particulate emissions a programme was carried out concentrating on tailpipe emissions as measured at the regulated particulate sampling point in a dilution tunnel. A previous literature study by CONCAWE had identified analytical techniques considered to be suitable for this application and which are capable of measuring both mass and number size distributions. Several variations of these techniques are available in the research field and the programme aimed to assess and compare their operation and performance.

Levels of ambient particulate matter have become the focus of increased attention over recent years as a result of studies suggesting an association between exposure and adverse health effects. Whilst research is continuing in many areas to identify a biological mechanism whereby this association can be explained, as yet there are only hypotheses. Causal relationships between observed health effects (i.e. increased hospital admissions, mortality, respiratory or heart problems) and any specific characteristic of the ambient aerosol have yet to be confirmed. Ambient aerosol has a complex chemistry and a wide range of physical properties, most of which undergo constant modification or transformation within the atmosphere. The particles in this aerosol may have originated either from natural or anthropogenic sources and may be either primary emissions (i.e. directly emitted to the atmosphere as particles) or secondary particles - formed by reaction of gas phase components.

Measurements of particulate matter (PM) from spark ignition (SI) engine exhaust using dilution tunnels will become more prevalent as emission standards are tightened. Hence, a study of the dilution process was undertaken in order to understand how various dilution related parameters affect the accuracy with which PM sizes and concentrations can be determined. A SI and a compression ignition (CI) engine were separately used to examine parameters of the dilution process; the present work discusses the results in the context of SI exhaust dilution. A Scanning Mobility Particle Sizer (SMPS) was used to measure the size distribution, number density, and volume fraction of PM. Temperature measurements in the exhaust pipe and dilution tunnel reveal the degree of mixing between exhaust and dilution air, the effect of flowrate on heat transfer from undiluted and diluted exhaust to the environment, and the minimum permissible dilution ratio for a maximum sample temperature of 52°C.

The transition from Euro2 to Euro3 emission standards for passenger diesel vehicles requires very good hydrocarbon control coupled with moderate, passive NOx reduction. In some cases, CO and PM conversion is also required. Passive NOx reduction, that is, selective catalytic reduction of NOx by hydrocarbons without delivery of hydrocarbon specifically for this purpose, requires good management of a scarce hydrocarbon resource. At the same time, increased requirements for HC control demand that unconverted HC be further minimized. Appropriately designed lean NOx catalysts with hydrocarbon adsorber capabilities offer very good HC control with moderate NOx reduction performance when fresh. However, certain zeolite structures appear quite unstable under high temperature aging, yielding significant declines in aged NOx performance. Instabilities can be avoided through proper choice of molecular sieve structure and composition, together with suitable washcoat structure.

We are interested in learning how commercial intake valve detergents contribute to combustion chamber deposits (CCD) in modern vehicles run for higher mileage. It is appealing to use short mileage (<5,000 miles) tests to evaluate the CCD performance of gasoline. However, the ability to extrapolate CCD performance to higher mileage (≥10,000 miles) is uncertain because of changes in CCD formation processes. For this reason, CCD from base fuel and a commercial IVD detergent package were generated in duplicate 10,000 mile tests using four 1996 model-year vehicles. The detergent package used a polyalkylamine detergent combined with a synthetic carrier fluid and achieved 94% intake valve deposit (IVD) reduction averaged across the four vehicles tested. The CCD weights were found to be variable between repeat tests but, when pooled across the four vehicle fleet, the CCD weights were found to be statistically the same for both the additized fuel and the base fuel.

There is continuing interest in understanding how fuel, fuel additives, and lubricants contribute to combustion chamber deposit (CCD) weights and compositions in order to better anticipate the impact of CCD on exhaust emissions and engine performance. For this reason, we have characterized a range of CCDs from bench engines and vehicles using solid state 13C Nuclear Magnetic Resonance Spectroscopy (NMR) and X-ray Photoelectron Spectroscopy (XPS). Differences in CCD composition and structure were related to the fuel, fuel additives, and engine oil used in the test. CCDs derived from most fuels run in modern engines are predominantly organic. The fraction of aromatic carbon ranges between 24 and 74% depending on fuels and test conditions over a test length of 1,000 to 20,000 miles. These aromatic carbons exist in predominantly 1 and 2 ring structures that are independent of the amount of aromatic carbon in the CCD.

The Port Fuel Injector (PFI) Deposit Test is a performance-based test procedure developed by the Coordinating Research Council and adopted by state and federal regulatory agencies for fuel qualification in the United States. To date, Southwest Research Institute (SwRI) has performed over 375 PFI tests between 1991 and 1998 for various clients. This paper details the analyses of these tests. Of the 375 tests, 199 were performed as keep-clean tests and 176 were performed as clean-up tests. The following areas of interest are discussed in this paper: Keep-clean versus clean-up test procedures Linearity of deposit formation Injector position effects as related to fouling Dirtyup / cleanup phenomena Seasonal effects This paper draws the conclusion that it is easier to keep new injectors from forming deposits than it is to clean up previously formed deposits. It was found that injector deposit formation is generally non-linear.

Carefully controlled intake valve deposit (IVD) cleanup testing is found to be an effective method for differentiating the effect of the deposit control additives on combustion chamber deposits (CCD). The IVD buildup procedure produces a consistent initial level of CCD that the cleanup additive, the additive of interest, continues to build on until the end of the cleanup test. This “end of cleanup” CCD is found to be as repeatable and differentiable a measurement as tests run under the more common “keep clean” type operation. While IVD cleanup testing induces a mid-test disturbance in the form of the end of buildup measurement, it aligns well with two key CCD protocols in terms of the higher additive treat rates used and the extended total test length. In an analysis of results from IVD cleanup tests run using four different engine/vehicle procedures on seven different additives, several findings stood out.

Diesel engine oils for heavy duty vehicles in the Japanese market must have good total base number (TBN) retention, high load carrying capacity, and corrosion control in order to meet the requirements of the engine designs, valve train system and operating conditions. As a result, detergent type oils with high ash and low dispersancy are the preferred formulation approach. However, the use of multigrade oils combining high ash and high dispersancy is gradually increasing. This is in response to user demands for extended drain performance and improved fuel economy. This research institute has taken a leadership position by initiating a study to develop low sulfated ash type engine oils. Engine tests have been carried out to study the performance of low sulfated ash oils. The results from work to develop a low ash diesel engine oil suitable for the next generation heavy duty vehicles are also reported.

The action of dispersants on the aggregation of carbon black (CB) particles, chosen as model for diesel soot present in lubricants, and their interactions with polymeric additives are investigated using Light Scattering techniques. The study of an ashless dispersant in a basestock shows that polyisobutylene (PIB) succinimides are associated in aliphatic media. The effect of PIB succinimides on the aggregation of CB suspensions is followed in 100 Neutral solutions of dispersant and non-dispersant polymethacrylate viscosity index improvers (respectively DPMA and PMA). The results show that ashless dispersants slow down the aggregation of CB suspensions without polymer or with non-dispersant PMA. The dispersant effect of DPMA is not improved by addition of ashless dispersant, in contrast to the case of the non-dispersant polymer.