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The authors have developed a measurement technique using a new digital telemeter which measures the piston secondary motion as ensuring high accuracy while under the operation. We applied this new digital telemeter to several measurements and analysis on the piston secondary motion that can cause piston noises, and here are some of the results from our measurement. We have confirmed that these piston motions vary by only several tenths of millimeter changes of the piston specifications such as the piston-pin offset and the center of gravity of the piston. As in other cases, we have found that a mere change of pressure in the crankcase or the amount of lubricating oil supplied on the cylinder bore varies the piston motion that may give effect on the piston noises.

India BS6 Stage2 (2023) regulations demand all gasoline direct injection (GDI) vehicles to meet particulate number emissions (PN) below 6x10+11# per km. Gasoline particulate filters (GPF) are a proven technology and enable high PN filtration efficiencies throughout the entire vehicle lifetime. One challenge for GPF applications could be the changing emission performance characteristics as a function of mileage due to collected ash and/or soot deposits with implications on back pressure losses. The main objective of this technical contribution is to study the above-mentioned challenges while applying Indian driving conditions and typical Indian climate and other ambient conditions. The substrate technology selected for this study is a high porosity GPF designed to enable the integration of a three-way functionality into the GPF, commonly described as catalyzed GPF (cGPF).

It is well understood that using lower viscosity engine oils can greatly improve fuel economy [1, 2, 3, 4]. However, it has been impossible to evaluate ultra-low viscosity engine oils (SAE 0W-12 and below) utilizing existing fuel economy test methods. As such, there is no specification for ultra-low viscosity gasoline engine oils [5]. We therefore developed firing and motored fuel economy test methods for ultra-low viscosity oils using engines from Japanese automakers [6, 7, 8]. This was done under the auspices of the JASO Next Generation Engine Oil Task Force (“TF” below), which consists mainly of Japanese automakers and entities working in the petroleum industry. Moreover, the TF used these test methods to develop the JASO GLV-1 specification for next-generation ultra-low viscosity automotive gasoline engine oils such as SAE 0W-8 and 0W-12. In developing the JASO GLV-1 specification, Japanese fuel economy tests and the ILSAC engine tests for evaluating engine reliability were used.

Hybrid vehicles (HVs) are becoming more widely used. Since HVs supplement engine drive with motor power, the lubricant oil temperature remains at a lower level than in a conventional gasoline vehicle. This study analyzed the effect of cylinder bore temperature and lubricant oil temperature on engine friction. The results showed that, although the lubricant oil temperature was not relevant, the bore temperature had significant effect on piston friction. It was found that raising the temperature of the middle section of the cylinder bore was the most effective way of reducing piston friction.

This paper presents the effects of a lubricant oil droplet on the start of combustion of a fuel-air mixture. Lubricant oil is thought to be a major source of low-speed pre-ignition in highly boosted spark ignition engines. However, the phenomenon has not yet been fully understood because its unpredictability and the complexity of the mixture in the engine cylinder make analysis difficult. In this study, a single oil droplet in a combustion cylinder was considered as a means of simplifying the phenomenon. The conditions under which a single oil droplet ignites earlier than the fuel-air mixture were investigated. Tests were conducted by using a rapid compression expansion machine. A single oil droplet was introduced into the cylinder through an injector developed for this study. The ignition and the flame propagation were observed through an optical window, using a high-speed video camera.

A study of diesel fuel as a lubricant for diesel engines was conducted with the aim of dramatically reducing engine friction and eliminating the need to change the lubricating oil. A prototype single-cylinder engine modified for diesel fuel lubrication was made, and it was confirmed that firing operation is possible. Piston friction during the firing operation was reduced by modifying the shape of the cylinder liner surface to improve the retention of the lubricating oil. The study produced valid findings concerning engine lubrication, not only with diesel fuel, but also with ultra-low viscosity oil.

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.

In April 2003, a small field study was initiated to evaluate the effect of lube oil formulations on ash accumulation in heavy-duty diesel DPFs. Nine (9) Fuel Delivery Trucks were retrofitted with passive diesel particulate filters and fueled with ultra low sulfur diesel which contains less than 15 ppm sulfur. Each vehicle operated in the field for 18 months or approximately 160,000 miles (241,401 km) using one of three lube oil formulations. Ash accumulation was determined for each vehicle and compared between the three differing lube oil formulations. Ash analyses, used lube oil analysis and filter substrate evaluations were performed to provide a complete picture of DPF operations. The evaluation also examined some of the key parameters that allows for the successful implementation of the passive DPF in this heavy-duty application.

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.

Recently, for the protection of the environment, the regulation of automobile fuel consumption and exhaust gas emission has been strengthened. To improve fuel economy, it is demanded that each engine part contributes to reducing the workload of the engine, even the engine lubrication oil pump. In response to this, a new variable discharge oil pump was developed. It is the world's first internal gear type oil pump that has electronically controlled continuously variable discharge. The work performed by the pump chiefly takes two forms: sliding friction of the rotor and pumping work which moves the oil. First, in developing a variable discharge oil pump, a new tooth profile of the rotor was developed to reduce its sliding friction. As a result, the sliding friction of the rotor was reduced by 34% while maintaining the same theoretical oil discharge rate. Next, a variable discharge mechanism using an internal gear was developed.

This paper describes lubricant technology which helps to prevent intake valve deposit (IVD) formation for use with conventional gasolines without detergents, as well as the IVD evaluation method used in testing. The FED 3462 method was modified to establish a new panel coking test method, with excellent correlation with the engine stand IVD test, for the quantitative evaluation of IVD. Tests have shown that IVD increases when the volatility of base oils becomes higher due to condensation and polymerization of engine oil additives. Furthermore, viscosity index improvers, metallic detergents and ashless dispersants have considerable effect on IVD formation. Based on various experiments, the authors have established a formulation technology for engine oils to lower IVD, which they incorporated in two newly formulated SG oils with lower IVD than conventional 5W-30 SG oil.

Fuel economy is one of the most important performance features for modern engine oils. For some time now, fuel efficient engine oils (called Energy Conserving II or EC-II) have been available in the marketplace. However, the performance of EC-II oils is only 2.7% Equivalent Fuel Economy Improvement (EFEI) as measured by the ASTM Sequence VI Engine Test. To meet future industry needs, more fuel efficient engine oils are desirable. In order to achieve this, a study of highly fuel efficient engine oils was initiated. An initial target of 3.9% EFEI was selected and several candidate oils were evaluated, some of which exceeded this target. The oils were evaluated using a chassis dynamometer using the U. S. EPA mode. The test results may be summarized: 5W-30 Prototype Oil containing MoDTC showed between 1.6 and 2.6% better fuel economy than conventional 5W-30 and 10W-30 EC-II oils. There was an optimum viscosity for maximum fuel economy using the EPA testing mode.

A bench engine test for evaluating the fuel efficiency of automotive crankcase oils using modern engines was developed. The fuel consumption was primarily proportional to the viscosity of the oils down to 5 mm2/s at operating temperatures, indicating that the use of low-viscosity oil was effective in improving fuel efficiency. This may be because the oil film would be formed easily, since sliding parts, such as valve train systems, in modern engines are finely finished. Organo molybdenum dithiocarbamates were effective in improving fuel efficiency at high temperature. A 2.7% improvement in fuel efficiency relative to conventional SAE 10W-30 oils was achieved by the combination of low-viscosity SAE 5W-20 oils and organo molybdenum dithiocarbamates under constant operating conditions with engine speed 1,500 rpm and torque 37.2 N•m.

Slip-controlled lock-up clutch systems are very efficient and greatly improve fuel economy. On the other hand, these systems can cause unstable vibrations including those known as “shudder vibrations”. In this study, the authors made a theoretical analysis of these unstable vibrations to clarify the fundamental frictional properties of automatic transmission fluids (ATFs) required for slip-controlled lock-up clutch systems. Based on this analysis, we established lubricant technology having a sufficient anti-shudder property and high torque capacity. Further, we developed a new test apparatus to evaluate the anti-shudder durability for lubricant development.

A newly developed fluorescent diagnostic system can measure the oil film thickness distribution through two-dimensional images with high sensitivity and quick response. This system consists of a filtered Xe-flash lamp, a filtered charge-coupled-device video camera, a personal-computer-based signal analyzer and lubricating oil with the fluorescent dye added. We have installed the system in a single cylinder research engine and measured the oil film thickness distribution around the piston under various operating conditions. One example of the results is that an oil spout from a gap in the first compression ring, which agrees with the measured oil consumption rate of the engine, was clearly observed at high engine speed.

The viscosity of automotive lubricants containing polymers decreases temporarily in the oil films of sliding parts with the increase in shear rate. This decrease sometimes causes surface damages such as bearing seizure and gear pitting. This paper describes the effect of polymers and base oils on viscosity under high shear rate conditions. The viscometer was newly developed to evaluate the viscosity at high shear rates. Shear rate can vary between 105 sec-1 and 106 sec-1. By using the viscometer, the effects of various factors such as polymer type, molecular weight, polar group and concentration on shear viscosity were investigated. The effects of polymer solubility and molecular weight distribution of base oils were also investigated.

This paper describes lubricant technology to enhance the durability of the low friction performance of gasoline engine oils which were formulated with molybdenum dithiodicarbamates (MoDTCs) as friction modifiers. This paper also describes an evaluation method which consists of three tests: (1) Our in-house rig test to simulate oil deterioration in an engine stand; (2) Quantitative analysis of MoDTC and ZnDTP in oils and; (3) A friction test (SRV). It was found that the low friction performance of fuel economy engine oils deteriorated primarily due to the consumption of MoDTC and ZnDTP. Calcium salicylates had better durability of low friction performance than calcium sulfonates. Furthermore, sulfurized compounds enhanced the durability. Based on these findings, an experimental oil was formulated.

The conventional hydraulic valve lifters, which eliminate the valve clearance adjustment, normally use the pressurized engine lubricant for the working fluid. We have developed a quite new type lifter, named “self-contained hydraulic valve lifter”, which possesses the working fluid in itself. Because the new type lifter is independent of the pressurized engine lubricant, it has some advantages, especially that it can be applied to the existing engine using the mechanical valve gear without almost any engine modifications. And we have confirmed that the self-contained hydraulic valve lifter has good characteristics and reliability and have applied it to the mass production engine (i.e. Toyota 1.3L gasoline engine) for the first time in the world. This paper describes the construction, the characteristics and the reliability of this lifter.

The wear mechanisms of the methanol engine were studied using dynamometer tests. Formic acid from methanol combustion mixes with the lubricant oil and attacks the metal surfaces. The iso tacho prorissis method was successfully applied to analyze the formic acid content of the used oil. A large amount of condensed water is also formed by methanol combustion and accelerates the wear. Wear can be effectively reduced by shortening lubricant oil change intervals, by using a special oil and by durable surface treatment of engine parts.

On the basis of the investigation of the airflow and temperature distributions between the car underside and the wind tunnel floor, methods to improve, the differential gear lubricant cooling performance in high speed running have been studied. It has been clarified that the differential gear lubricant temperature is nearly dominated by the convective heat transfer coefficient and the air temperature around the differential gear carrier. Control of the heat transfer coefficient and the air temperature around the differential gear carrier through the modification of the car underside configuration was found to be the most efficient method to decrease the temperature of the differential gear lubricant.