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Panel cokers have been used for a number of years for the evaluation of lubricant formulations with respect to thermal oxidative stability. There are, however, a number of drawbacks to the technique, particularly related to variability of the test and correlations to real engine performance. As a consequence of this, work has been undertaken to develop a new thermal oxidative screen test which provides greater flexibility and better correlation to engine tests. The glass panel coker test has been developed from a combination of several screen tests, and consists of a heated sump, where the lubricant is aerated and has NO2 additions, and from which oil is circulated over a high temperature metal surface. The apparatus largely consists of standard laboratory glassware, and as such is easily customisable to incorporate additional features, for example simulated fuel or water dilution.

It has long been understood that the piston assembly of the internal combustion engine accounts for a significant proportion of total engine friction. Modern engines are required to have better fuel economy without sacrificing durability. The pursuit of better fuel economy drives trends like downsizing, turbocharging and direct injection fuelling systems that increase cylinder pressures and create a more arduous operating environment for the piston ring / cylinder bore tribocouple. The power-cylinder lubricant is therefore put under increased stress as modern engine technology continues to evolve. The conventional approach to investigating fundamental power-cylinder tribology employs bench-tests founded on assumptions which allow for simplification of experimental conditions.

Phosphorus is known to reduce the effectiveness of the three-way catalysts commonly used by automobile manufacturers by deactivating the catalyst. This process occurs as zinc dialkyldithiophosphate (ZDP) decomposes in the engine oil, creating many phosphorus species, which provide excellent wear protection of the engine but can also interact with the active sites of the three-way catalyst. This reactivity has led to API specifications for engine oils with lower concentrations of phosphorus. In order to further minimize catalyst deactivation without compromising wear protection, a novel ZDP technology was designed for engine oil applications. This novel ZDP was designed to minimize the amount of phosphorus produced via volatilization during engine operation while maintaining engine wear protection.

For many years, governments have driven the improvement of fuel economy in transportation through tightening legislation. This effort has focused on passenger cars, but is increasingly concerned with heavy-duty vehicles (HDV). The combination of this regulatory focus with the ever present desire for low cost of ownership in commercial vehicles is giving increased pressure to deliver more fuel efficiency from the lubricants. In order to deliver improved fuel efficiency, suitable test methodology is needed to give repeatable discriminatory results that not only help in the advance of technology, but can also highlight the magnitude of the benefit expected in real-world applications. Typical on-road driving has significant variation in fuel consumption due to driver inconsistency, changes in rolling resistance and changeable ambient conditions.

Requirements to reduce emissions and improve vehicle fuel economy continue to increase, spurred on by agreements such as the Kyoto Protocol. Lubricants can play a role in improving fuel economy, as evidenced by the rise in the number of engine oil specifications worldwide that require fuel economy improvements. A novel friction modifier technology has been developed to further improve vehicle fuel economy. The development of this novel friction modifier technology which contains only N,O,C,H was previously published along with the initial demonstration of performance in motorized Toyota engines. In order to validate this performance in fired engine tests, oil was evaluated in a Toyota Corolla Fielder with a 1500 cc gasoline engine. Testing was conducted in the Japanese 10-15 and JC08 modes, as well as the European EC mode, and the US FTP mode.

A novel ultrasonic viscometer for in-situ applications in engine components is presented. The viscosity measurement is performed by shearing the solid-oil contact interface by means of shear ultrasonic waves. Previous approaches to ultrasonically measure the viscosity suffer from poor accuracy owing to the acoustic miss-match between metal component and lubricant [1]. The method described overcomes this limitation by placing an intermediate matching layer between the metal and lubricant. Results are in excellent agreement with the ones obtained with the conventional viscometers when testing Newtonian fluids. This study also highlights that when complex mixtures are tested the viscosity measurement is frequency dependent. At high ultrasonic frequencies, e.g. 10 MHz, it is possible to isolate the viscosity of the base, while to obtain the viscosity of the mixture it is necessary to choose a lower operative frequency, e.g. 100 kHz, to match the fluid particle relaxation time.

Several engine manufacturers are offering 4-stroke marine engines in order to meet 1998 US EPA emissions regulations requiring a 75% hydrocarbon reduction by 2006. These 4-stroke marine engines have been lubricated with passenger car motor oil in the past; however, the environment in which these engines operate is quite different from a passenger car engine. Perhaps the biggest differences are that marine engines do not use a closed loop cooling system, and they often operate in a corrosive salt water environment. They may be operated for extended periods of time at low speed while trolling, allowing build-up of water and fuel in the engine oil. For these reasons, oil used in this application should have corrosion inhibiting properties that are much better than what is found in passenger car oil. In addition, boats are often used seasonally and stored for long periods of time during the winter.

Gasoline direction injection (GDI) engines have been widely used by light-duty vehicle manufacturers in recent years to meet stringent fuel economy and emissions standards. Particulate Matter (PM) mass emissions from current GDI engines are primarily composed of soot particles or black carbon with a small fraction (15% to 20%) of semi-volatile hydrocarbons generated from unburned/partially burned fuel and lubricating oil. Between 2017 and 2025, PM mass emissions regulations in the USA are expected to become progressively more stringent going down from current level of 6 mg/mile to 1 mg/mile in 2025. As PM emissions are reduced through soot reduction, lubricating oil derived semi-volatile PM is expected to become a bigger fraction of total PM mass emissions.

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.

Operational Diesel Particulate Filter (DPF) technology traps and oxidizes soot particulate, lowering particulate emissions. Additionally they trap other non combustible material which is deposited as ash within the filter. The trapping of this material leads to increased backpressure on the engine, giving an increase in fuel consumption, and requires periodic servicing to remove. This work demonstrates the emission effects of this increase in backpressure and develops a method of realistically accelerating this ash deposition mechanism yielding a bench test for the study of this phenomenon.

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.

Improvements in vehicle fuel efficiency continue to be a significant driver for all parties involved in the operation of automotive vehicles. The cost of vehicle ownership, energy security and the need to limit greenhouse gas emissions are all factors in driving the need to improve operating efficiency. One particular area of interest is engine lubricants which are known to have a significant effect on the overall efficiency of a vehicle. The decision to move to a more fuel efficient lubricant is enhanced since the incremental cost of introducing a fuel efficient lubricant is low in comparison to the potential fuel saving leading to a favourable economic decision for a fleet owner. This paper describes a study undertaken where upon two significantly different UK buses were taken directly from the FirstGroup fleet and used for a period of two weeks for fuel economy testing. The testing centres on two commercially available engine lubricants and was completed on a test track in the UK.

To meet increasingly stringent emissions and fuel economy regulations, many Original Equipment Manufacturers (OEMs) have recently developed and deployed small, high power density engines. Turbocharging, coupled with gasoline direct injection (GDI) has enabled a rapid engine downsizing trend. While these turbocharged GDI (TGDI) engines have indeed allowed for better fuel economy in many light duty vehicles, TGDI technology has also led to some unintended consequences. The most notable of these is an abnormal combustion phenomenon known as low speed pre-ignition (LSPI). LSPI is an uncontrolled combustion event that takes place prior to spark ignition, often resulting in knock, and has been known to cause catastrophic engine damage. LSPI propensity depends on a number of factors including engine design, calibration, fuel properties and engine oil formulation. Several engine tests have been developed within the industry to better understand the phenomenon of LSPI.

Life Cycle Assessment (LCA) is a methodology used to determine quantitatively the environmental impacts of a range of options. The environmental community has used LCA to study all of the impacts of a product over its life cycle. This analysis can help to prevent instances where a greater degree of environmental harm results when changes are made to products based on consideration of impacts in only part of the life cycle. This study applies the methodology to engine lubricants, and in particular chlorine limits in engine lubricant specifications. Concern that chlorine in lubricants might contribute to emissions from vehicle exhausts of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), collectively called PCDD/F, led to the introduction of chlorine limits in lubricant specifications. No direct evidence was available linking chlorine in lubricants to PCDD/F formation, but precautionary principles were used to set lubricant chlorine limits.

The new American Petroleum Institute (API) categories for passenger car motor oils have focused on improving fuel economy and reducing emissions. This has resulted in more fuel efficient oils being developed by lowering the viscometrics and by adding friction modifiers. The emissions reductions have resulted from lowering the percent phosphorus (%P) in the engine oils because phosphorus has been found to poison the catalyst in the catalytic converter. When friction modifiers were introduced, researchers from four Japanese motorcycle manufacturers published the results of their studies (SAE 961217) which indicated that low friction oil can cause too much slippage in starter motor clutches, one-way limited slip clutches, and wet multi-plate clutches. In that same study they reported that engine manufacturers use 10W-30 grade oil to develop new engine technology, and gear pitting was observed with oils of viscosity grades lower than 10W-30 in all four manufacturers' motorcycle engines.