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As part of the International Lubricant Standardization and Approval Committee's (ILSAC) goal of developing a global automatic transmission fluid (ATF) specification, members have been evaluating test methods that are currently used by various automotive manufacturers for qualifying ATF for use in their respective transmissions. This report deals with comparing test methods used for determining torque capacity in friction systems (shifting clutches). Three test methods were compared, the Plate Friction Test from the General Motors DEXRON®-III Specification, the Friction Durability Test from the Ford MERCON® Specification, and the Japanese Automotive Manufacturers Association Friction Test - JASO Method 348-95. Eight different fluids were evaluated. Friction parameters used in the comparison were breakaway friction, dynamic friction torque at midpoint and the end of engagement, and the ratio of end torque to midpoint torque.

In recent years, the slip lock-up mechanism has been adopted widely, because of its fuel efficiency and its ability to improve NVH. This necessitates that the automatic transmission fluid (ATF) used in automatic transmissions with slip lock-up clutches requires anti-shudder performance characteristics. The test methods used to evaluate the anti-shudder performance of an ATF can be classified roughly into two types. One is specified to measure whether a μ-V slope of the ATF is positive or negative, the other is the evaluation of the shudder occurrence in the practical vehicle. The former are μ-V property tests from MERCON® V, ATF+4®, and JASO M349-98, the latter is the vehicle test from DEXRON®-III. Additionally, in the evaluation of the μ-V property, there are two tests using the modified SAE No.2 friction machine and the modified low velocity friction apparatus (LVFA).

Increasingly stringent environmental regulations requiring lower CO2 emissions and higher fuel economy have made it essential to develop vehicles with superior fuel efficiency and cleaner emissions. At the same time, there is growing demand for even more powerful and quieter vehicles. To help satisfy these requirements, Toyota Motor Corporation has developed a new 8-speed automatic transmission for front wheel drive vehicles, incorporating its first compact torque converter with a multiple disk lock-up mechanism. This newly developed compact torque converter with a multiple disk lock-up mechanism was designed under the Toyota New Global Architecture (TNGA) development concept to achieve an excellent balance between higher efficiency through the commonization of components and stronger product appeal through installation on a whole family of transmissions. This compact torque converter is compatible with a variety of engines from inline 4-cylinder to V6 configurations.

Fuel economy measurement test is one of important engine tests to establish fuel economy engine oil performance standard to support CO2 emission reduction efforts in the automotive industry. On the other hand, it is difficult to develop an engine test without appropriate engine hardware that is designed to utilize low viscosity engine oils. A new firing fuel economy test was developed based on 2ZR-FXE engine designed for hybrid powertrain. The new test procedure aimed to provide the tool to evaluate new low viscosity grades such as 0W-8 and 0W-12 that were adapted in SAE J300 in 2015.

This paper demonstrates the development of a full multi-body vehicle model and its use in virtual design and troubleshooting of a vehicle response to throttle input. The multibody model is divided into three main subsystems: the chassis, the driveline and the powertrain subsystems. The chassis system includes a complete representation of both the front and the rear suspensions, both the front and rear subframes, and the vehicle body. The driveline system includes the output shafts from the transmission unit to the tires. The powertrain system includes complete representation of the cranktrain for a V6 combustion engine. Also included in the powertrain is a nonlinear representation of the gearbox where bearing clearances and gear lashes are considered. The cranktrain torque output is linked to the transmission using a torque converter model. The vehicle components are virtually assembled together through different joint types, force elements, and kinematic constraints.

We report in this paper our newly developed technology applied to ILSAC GF-5 0W-20 engine oil that offers great fuel economy improvement over GF-4 counterpart, which is a key performance requirement of modern engine oil to reduce CO2 emissions from a vehicle. Our development strategy of the oil consisted of two elements: (1) further friction reduction under mixed and hydrodynamic lubrication conditions considering use of roller rocker arm type valve train system and (2) lowering viscosity at low temperature conditions to improve fuel economy under cold cycles. Use of roller rocker arm type valve train system has been spreading, because of its advantage of reducing mechanical friction. Unlike engine with conventional direct-acting type valve train system, lubrication condition of engine with the roller rocker arm type valve train system has higher contribution of mixed or hydrodynamic lubrication conditions rather than boundary lubrication condition.

Toyota Motor Corporation has developed an innovative 10-speed longitudinal automatic transmission called the Direct Shift-10AT. The Direct Shift-10AT is a significant contributor to the excellent dynamic performance of the Lexus LC500. A wide gear spread with close gear ratios allows for rhythmical shifting, smooth and powerful acceleration from a standing start, along with quiet and relaxed high- speed driving due to low engine speeds. The lock-up area is expanded to a wider range of vehicle speeds (excluding low-speed regions such as when starting off), by the adoption of a multi-plate lock-up clutch, a newly developed torque converter, and a high-precision controller. As a result, the shift control can match the driver's intended operation more directly because the main cause of the response delay (transient changes in engine speed (flare)) is eliminated. Furthermore, fuel economy is improved due to the adoption of low friction clutches.

Toyota has developed a new continuously variable transmission (CVT) called "Direct Shift-CVT" which is for 2.0-liter class vehicles. This CVT provided not only power transmission by a metal belt held with a conventional pulley but also additional gear mechanism. This CVT is developed to improve fuel efficiency, acceleration characteristic, and quietness. At this CVT, the startup low gear ratio is achieved by gear mechanism and the power is switched by clutches. Since the belt-pulley portion can be realized to be wide range by using only high gear ratio range, the input load into belt-pulley portion is reduced and unprecedented compact and high efficient belt-pulley portion is established. Consequently, the high efficiency in all fields from startup acceleration to high speed driving is achieved to improve fuel efficiency.

Further fuel economy improvement of the internal combustion engine is indispensable for CO2 reduction in order to cope with serious global environmental problems. Although lowering the viscosity of engine oil is an effective way to improve fuel economy, it may reduce the wear resistance. Therefore, it is important to achieve both improved fuel economy and reliability. We have developed new 0W- 8 engine oil of ultra-low viscosity and achieved an improvement in fuel economy by 0.8% compared to the commercial 0W-16 engine oil. For this new oil, we reduced the friction coefficient under boundary lubrication regime by applying an oil film former and calcium borate detergent. The film former increased the oil film thickness without increasing the oil viscosity. The calcium borate detergent enhanced the friction reduction effect of molybdenum dithiocarbamate (MoDTC).

The study described in this paper covers the development of the Sequence IVB low-temperature valvetrain wear test as a replacement test platform for the existing ASTM D6891 Sequence IVA for the new engine oil category, ILSAC GF-6. The Sequence IVB Test uses a Toyota engine with dual overhead camshafts, direct-acting mechanical lifter valvetrain system. The original intent for the new test was to be a direct replacement for the Sequence IVA. Due to inherent differences in valvetrain system design between the Sequence IVA and IVB engines, it was necessary to alter existing test conditions to ensure adequate wear was produced on the valvetrain components to allow discrimination among the different lubricant formulations. A variety of test conditions and wear parameters were evaluated in the test development. Radioactive tracer technique (RATT) was used to determine the wear response of the test platform to various test conditions.

To meet increasing driveability expectation and government stringent fuel economy regulations reducing CO2 emissions of passenger cars; Toyota developed a new 8-speed automatic transmission "Direct Shift-8AT". Direct Shift-8AT is the first stepped automatic transmission model based on “TNGA” philosophy. New models which received Direct Shift-8AT are the new Camry, Highlander and Sienna. Direct Shift-8AT has an innovative control method with gear train and torque converter models, providing enhanced driveability and fuel economy performance through high efficiency transmission technology. This paper describes details of the new technology and vehicle performance.

A new concept of an electromagnetic torque converter for hybrid electric vehicles is proposed. The electromagnetic torque converter, which is an electric system comprised of a set of double rotors and a stator, works as a high-efficiency transmission in the driving conditions of low gear ratio including a vehicle moving-off and as a starting device for an internal combustion engine. Moreover, it can be used for an electric vehicle driving as well as for a regenerative braking. In this concept, a high-efficiency drivetrain system for hybrid electric vehicles is constructed by replacing a fluid-type torque converter with the electromagnetic torque converter in the automatic transmission of a conventional vehicle. In this paper, we present the newly developed electromagnetic torque converter with a compact structure that enables mounting on a vehicle, and we evaluate its transmission efficiency by experiment.

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.

Torque loss reduction at differential gear unit is important to improve the fuel economy of automobiles. One effective way is to decrease the viscosity of lubricants as it results in less churning loss. However, this option creates a higher potential for thin oil films, which could damage the mechanical parts. At tapered roller bearings, in particular, wear at the large end face of rollers and its counterpart, known as bearing bottom wear is one of major failure modes. To understand the wear mechanism, wear at the rolling contact surface of rollers and its counterpart, known as bearing side wear, was also observed to confirm the wear impact on the tapered roller bearings. Because gear oils are also required to avoid seizure under extreme pressure, the combination of a phosphorus anti-wear agent and a sulfurous extreme pressure agent are formulated.

Due to the advancement of engine performance, large volumes of oil circulate within a narrow internal space of passenger car engines. This phenomenon often leads to oil foaming and aeration problems. In this study, we developed a method for predicting the rate of engine oil aeration from specific engine parameters and running conditions. Engine tests show that the rate of oil aeration is stable throughout the process between bubble release from the oil surface and aeration. Additionally, bubble size affects its release rate from the oil surface. Utilizing both of these assumptions, our prediction method calculates aeration rate by evaluating bubble number and size.

Two types of new conceptual lead free overlays are developed for automotive internal combustion(IC) engine bearings. The overlays are consisted of molybdenum disulfide(MoS2) and polyamideimide(PAI) resin for binding. One of the overlays is suitable for diesel engines with higher unit load and the other overlay is suitable for gasoline engines with higher sliding velocity. Both overlays indicate good corrosion resistance and wear resistance comparing with conventional lead base overlay. Moreover, higher fatigue resistance is obtained in combination with high performance lead free bearing alloy. These new bearings have the potential to become alternative materials to conventional copper lead bearings with lead base overlay.

Toyota Motor Corporation has developed a new drivetrain for their flagship Lexus LFA sports car. Passionate driving experience was pursued at the forefront of development. Superior vehicle performance, handling, and responsiveness that seem to anticipate the driver's intentions are achieved. Special vehicle packaging and component placement are adopted in the LFA in order to realize such performance. The engine, clutch, and front counter gear are positioned at the front of the vehicle, and the transaxle at the rear. The engine and transaxle are connected by a rigid torque tube. The transaxle is an automated manual transmission equipped with an electrohydraulic actuator for controlling both the shift and clutch operations. This actuator enables accurate control of the transmission and extremely quick response to shift paddle operation by the driver. This paper describes a general outline of the drivetrain and each component that has significantly contributed to LFA product appeal.

This paper describes the slip ring system for a new hybrid system using an electromagnetic torque converter or an electromagnetic coupling. The slip ring system, which enables electric power transmission between a winding rotor and an inverter fixed on a case, is a key component for establishing a new highly efficient hybrid system. Reducing the wear of the brushes in the slip ring system is a major topic of this research. To achieve this objective, brush wear characteristics were investigated using test-piece experiments that simulated the hybrid system environment. By clarifying these characteristics, the structure of a slip ring system for reducing brush wear was identified and a wear prediction method was constructed.

Oil pump down sizing is one of the effective method to improve engine friction loss. Reducing the required amount of lubricating engine oil can be achieved by the application of a new crankshaft bearing with an eccentric oil groove. By adopting a bearing with an eccentric groove, we found the well balanced specification which can keep the necessary amount of oil to the crankshaft pin and reduce leaking oil from crankshaft main journal. Measuring oil amount distribution in engine running condition simultaneously and checking capability of eliminating contamination analytically have achieved.

Recently, engines achieving high power levels are becoming increasingly common. The trend is toward increasing the inflow of lubricating oil into the crankcase through several factors (for example, increasing the flow rate of the cooling oil jets in order to reduce the thermal load of the pistons). In addition, the mechanical losses induced by the motion of the crankshaft and connecting rods through the additional oil are intensified due to the higher engine speeds at maximum power. In this article, we confirmed a method of separating the pumping loss and the agitation loss by measuring the pressure in the crankcase and an empirical formula was found for predicting pumping loss from displacement and ventilating area. We also investigated the effect of reducing the lubrication oil flow rate, as well as other factors affecting the oil flow, on the mechanical loss at high engine speeds.