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1Increasing adoption of downsized, boosted, spark-ignition engines has improved vehicle fuel economy, and continued improvement is desirable to reduce carbon emissions in the near-term. However, this strategy is limited by damaging preignition events which can cause hardware failure. Research to date has shed light on various contributing factors related to fuel and lubricant properties as well as calibration strategies, but the causal factors behind an individual preignition cycle remain elusive. If actionable precursors could be identified, mitigation through active control strategies would be possible. This paper uses artificial neural networks to search for identifiable precursors in the cylinder pressure data from a large real-world data set containing many preignition cycles. It is found that while follow-up preignition cycles in clusters can be readily predicted, the initial preignition cycle is not predictable based on features of the cylinder pressure.

In this work, a novel bearing test rig was used to evaluate the impact of oil viscoelasticity on friction torque and oil film thickness in a hydrodynamic journal bearing. The test rig used an electric motor to rotate a test journal, while a hydraulic actuator applied radial load to the connecting rod bearing. Lubrication of the journal bearing was accomplished via a series of axial and radial drillings in the test shaft and journal, replicating oil delivery in a conventional engine crankshaft. Journal bearing inserts from a commercial, medium duty diesel engine (Cummins ISB) were used. Oil film thickness was measured using high precision eddy current sensors. Oil film thickness measurements were taken at two locations, allowing for calculation of minimum oil film thickness. A high-precision, in-line torque meter was used to measure friction torque. Four test oils were prepared and evaluated.

In the last decade, numerous studies have been conducted to investigate the mechanism of Low Speed Pre-Ignition (LSPI) in Turbocharged Gasoline Direct Injection (TGDi) engines. According to technical reports, engine oil formulations can significantly influence the occurrence of LSPI particularly when higher levels of calcium-based additives are used, increasing the tendency for LSPI events to occur. While most of the studies conducted to date utilized engine tests, this paper evaluates the effect of engine oil formulations on LSPI under real-world driving conditions, so that not only the oil is naturally aged within an oil change interval, but also the vehicle is aged through total test distance of 160,000 km. Three engine oil formulations were prepared, and each tested in three vehicles leading to an identical fleet totaling nine vehicles, all of which were equipped with the same TGDi engine.

Downsized gasoline engines, coupled with gasoline direct injection (GDI) and turbocharging, have provided an effective means to meet both emissions standards and customers’ drivability expectations. As a result, these engines have become more and more common in the passenger vehicle marketplace over the past 10 years. To maximize fuel economy, these engines are commonly calibrated to operate at low speeds and high engine loads – well into the traditional ‘knock-limited’ region. Advanced engine controls and GDI have effectively suppressed knock and allowed the engines to operate in this high efficiency region more often than was historically possible. Unfortunately, many of these downsized, boosted engines have experienced a different type of uncontrolled combustion. This combustion occurs when the engine is operating under high load and low speed conditions and has been named Low Speed Pre-Ignition (LSPI). LSPI has shown to be very damaging to engine hardware.

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.

The growing need for improved fuel economy is a global challenge due to continuously tightening environmental regulations targeting lower CO2 emission levels via reduced fuel consumption in vehicles. In order to reach these fuel efficiency targets, it necessitates improvements in vehicle transmission hardware components by applying advanced technologies in design, materials and surface treatments etc., as well as matching lubricant formulations with appropriate additive chemistry. Axle lubricants have a considerable impact on fuel economy. More importantly, they can be tailored to deliver maximum operational efficiency over specific or wide ranges of operating conditions. The proper lubricant technology with well-balanced chemistries can simultaneously realize both fuel economy and hardware protection, which are perceived to have a trade-off relationship.

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.

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.

Forthcoming on-highway 2005/2007 European and North American emission regulations will require modern diesel engines to be equipped with Diesel Particulate Filters (DPF) capable of trapping up to 99% of the exhaust particulate matter. Since diesel particulates (soot) accumulate in the filter over time, the overall system needs to be regenerated by attaining the ignition temperature of soot, which in the presence of oxygen is >600 °C. Catalyzed DPFs regenerate at temperatures as low as ∼300 °C. One of the major issues facing OEMs, aftertreatment system manufacturers, and lubricant formulators is the potential effects of the lubricant-derived ash deposits and their impact on a pressure increase across filters, as well as overall filter performance and its service characteristics.

Soot related viscosity increase has been reported as a field issue in some diesel engines and this led to the development of the T-11 engine test, incorporated in the Mack EO-N Premium Plus 03 specification (014 GS 12037). This study compares T-11 laboratory engine tests and vehicle field tests and seeks to confirm the correlation between them. The findings are that the T-11 test provides an effective screening tool to investigate soot related viscosity increase, and the severity of the engine test limits gives a substantial margin of safety compared to the field. A complementary study was conducted in conjunction with this work that focuses on the successful application of electrochemical sensor technology to diagnose soot content and soot related viscosity increase. This will be the subject of a separate paper.

The Sequence IIIG is a newly developed 100 hour test used to evaluate the performance of crankcase engine oils in the areas of high temperature viscosity increase, wear, deposits, pumpability, and ring sticking for the North American GF-4 standard. Data from the ASTM Precision Matrix, completed in the spring of 2003, along with early reference data from the Lubricant Test Monitoring System (LTMS) showed unexpected test results for selected oils and indicated that percent viscosity increase and pumpability were highly correlated with oil consumption. This correlation led to an intensive study of the factors that influence oil consumption and an attempt to compensate for non-oil related oil consumption through a model based adjustment of the results. The study and scrutiny of the IIIG data has led to more uniform oil consumption in the test and improved test precision, and has eliminated the need for a correction equation based on non-oil related oil consumption.

The effects of lubricating oil on friction and wear were investigated using light-duty 2.2L compression ignition direct injection (CIDI) engine components for bench testing. A matrix of test oils varying in viscosity, friction modifier level and chemistry, and base stock chemistry (mineral and synthetic) was investigated. Among all engine oils used for bench tests, the engine oil containing MoDTC friction modifier showed the lowest friction compared with the engine oils with organic friction modifier or the other engine oils without any friction modifier. Mineral-based engine oils of the same viscosity grade and oil formulation had slightly lower friction than synthetic-based engine oils.

The effects of reduced fuel injection pressure on the cold start performance of a GDI engine have been studied in a single-cylinder, optically-accessible research engine. Two Delphi Automotive Systems DI-G injectors, with included spray cone angles of 60° and 80° respectively, were studied. Both injectors are designed to operate at a nominal fuel line pressure of 10 MPa. For the study they were operated at several fuel feed pressures between 10 MPa and 2 MPa. Two start of injection timings (50° and 100° ATDC) were examined. Cold start performance was characterized by measurements of the GIMEP, COV of GIMEP, and total engine out UHCs. Simultaneous Planar Laser Induced Fluorescence (PLIF) and Mie Scattering images of the fuel spray were used to observe spray penetration, mixing, and in-cylinder fuel distribution throughout the intake and compression strokes. Ultimately these images were used to explain observed performance differences.

Recently, research and testing of oxygenated diesel fuels has increased, particularly in the area of exhaust emissions. Included among the oxygenated diesel fuels are blends of diesel fuel with ethanol, or E diesel fuels. Exhaust emissions testing of E diesel fuel has been conducted by a variety of test laboratories under various conditions of engine type and operating conditions. This work reviews the existing public data from previous exhaust emissions testing on E diesel fuel and includes new testing performed in engines of varied design. Emissions data compares E diesel fuel with normal diesel fuel under conditions of different engine speeds, different engine loads and different engine designs. Variations in performance under these various conditions are observed and discussed with some potential explanations suggested.

A new generation of fluid technology using novel diesel fuel detergent/dispersant chemistry provides a multitude of beneficial effects to the diesel engine, especially the latest model designs. In addition to improved injector, valve and combustion chamber deposit removal, the additive restores power, fuel economy, performance and emission levels1. Positive observations have also been documented along with improved performance concerning crankcase lube viscosity, soot loading and TBN retention. An even greater added benefit is the inherent capability of the fuel additive to deal with several EGR issues now prominent with the introduction of new engines. Recent research, reported herein, has uncovered the extensive efficacy of this chemistry for piston durability and neutralization of ring corrosion phenomena. All of the beneficial additive attributes are further enhanced with increased oxidative and thermal fuel stability and no loss of filterability.

Throughout the evolution of the automobile, passenger car motor oils have been developed to address issues of wear, corrosion, deposit formation, friction, and viscosity stability. As a result, the internal combustion engines are now developed with the expectation that the lubricants to be used in them will deliver certain performance attributes. Metallurgies, clearances, and built-in stresses are all chosen with certain expectations from the lubricant. A family of chemicals that has been universally used in formulating passenger car motor oils is zinc dithiophosphates (ZDPs). ZDPs are extremely effective at protecting highly stressed valve train components against wear failure, especially in engine designs with a sliding contact between cams and followers. While ZDPs' benefits on wear control are universally accepted, ZDPs have been identified as the source of phosphorus, which deactivates noble metal aftertreatment systems.

Experiments have been conducted in a laminar flow system and in a research engine to investigate the effect of additives on the combustion of gasoline-like fuels. The purpose of the laminar system is to enable rapid screening of additives to determine which, if any, have an enhancing effect on the early stages of combustion, especially under conditions of poor fuel vaporization which exist during cold-start in a spark ignited engine and which make flame propagation difficult to start and sustain. The base fuel used in the laminar and engine systems was a 9 component mixture formulated to simulate those components of gasoline expected to be present in the vapor phase in the intake system of an engine under cold-start conditions. In the laminar system, the pre-mixed, pre-vaporized fuel-air mixture is ignited and a time history of the combustion generated, hydroxyl radical chemiluminescence is recorded.

The effects of lubricating oil on friction and engine-out emissions in a light-duty 2.2L compression ignition direct injection (CIDI) engine were investigated. A matrix of test oils varying in viscosity (SAE 5W-20 to 10W-40), friction modifier (FM) level and chemistry (MoDTC and organic FM), and basestock chemistry (mineral and synthetic) was investigated. Tests were run in an engine dynamometer according to a simulated, steady state FTP-75 procedure. Low viscosity oils and high levels of organic FM showed benefits in terms of fuel economy, but there were no significant effects observed with the oils with low MoDTC concentration on engine friction run in this program. No significant oil effects were observed on the gaseous emissions of the engine. PM emissions were analyzed for organic solubles and insolubles. The organic soluble fraction was further analyzed for the oil and fuel soluble portions.

The engine-out emissions and fuel consumption rates for a modern, heavy-duty diesel engine were compared when fueling with a conventional diesel fuel and three water-blend-fuel emulsions. Four different fuels were studied: (1) a conventional diesel fuel, (2) PuriNOx,™ a water-fuel emulsion using the same conventional diesel fuel, but having 20% water by mass, and (3,4) two other formulations of the PuriNOx™ fuel that contained proprietary chemical additives intended to improve combustion efficiency and emissions characteristics. The emissions data were acquired with three different injection-timing strategies using the AVL 8-Mode steady-state test method in a Caterpillar 3176 engine, which had a calibration that met the 1998 nitrogen oxides (NOX) emissions standard.