For the reduction of fuel consumption, recent engines require higher cylinder pressures and reduced mechanical losses. For those reasons, engine bearings are used in higher load by higher cylinder pressure, and are required to improve durability and reliability. There are two types of surface treatment procedures for engine bearings. One is resin coating and the other is soft metal plating. Bismuth alloy plating was developed to improve fatigue resistance and resin coating containing barium sulfate and DLC coated journals were developed to improve seizure resistance. Moreover, onion-like carbon added in resin coating is evaluated to improve tribological performance. This report introduces those research and developments.

The advanced CVT metal belt enhances power transmission efficiency and addresses misalignment by combining three ideas:shorter rocking distance, element contact shape, and narrow-angled multi-V-surface shape. Also, by modifying the contact surface between the element and the pulley, it is possible to enhance the power transmission efficiency in the middle ratio.

The electrification of automobiles is progressing rapidly with the tightening of exhaust gas regulations and the demand for low fuel consumption worldwide. EVs do not have an internal combustion engine as a power source or power generator, it has a short cruising range, which is a major obstacle for users. Therefore, it is essential to expand the cruising range for the further spread of EVs in the future. Consideration is being given to combining EVs with transmissions to extend cruising range. Most of the EVs currently on the market do not have a transmission and use a reduction mechanism with a fixed reduction ratio. This is because the motor can generate a large torque from the start and can cover high revolution, so a transmission with a wide range of gear ratios,which has been used in internal combustion engines, is not essential. However, it is expected that transmissions will also be used in high-end electrified sports cars and SUVs because it will be possible not only to extend cruising range but also to increase maximum torque and maximum vehicle speed. This paper introduces the relatively latest transmission technology for EVs that has been researched so far.

This paper presents a compact, lightweight direct-drive in-wheel system for electric vehicles (EVs), which combines the motor, inverter, and brake into a single unit. This enables the installation of the entire system into the wheel and more expansive interior and battery installation spaces. Proposed system transmits the high drive force directly to the wheels, and its lightweight design and high power density significantly limit the weight increase traditionally associated with in-wheel units. Moreover, the system does not require a substantial change to the existing configuration of the suspension and other components. Driveshafts and other indirect mechanisms have been eliminated, allowing motor power to be applied directly to EV operation. This reduces energy loss and increases the range on a single charge compared to existing EVs.

Battery electric vehicles (BEVs) are attracting attention as one solution to achieving carbon neutrality. Battery cooling systems are very important in BEVs. Water-cooled systems are widely used because of their superior cooling performance and cost advantages. In such water-cooled systems, the battery is cooled by using coolant for engine vehicles. However, coolant has very high electrical conductivity, as high as that of seawater. If the high-voltage area is exposed to coolant in the event of a cooling system failure or an automobile accident, the battery may be short-circuited, resulting in abnormal heating and smoking. We have developed low conductivity coolant to ensure excellent safety.

To extend the lifetime of machines, proactive maintenance has been recommended. Especially, predicting the lifetime of oxidation inhibitors in lubricating oil is important. For this reason, there is a need to develop an analysis method for lubricating oil that can easily measure the residual rate of oxidation inhibitors at a low cost. Therefore, we proposed Lubricating oil Image Analysis (LIA), which is lubricating oils degradation diagnosis using image analysis technology. This method is capable of quantitative color analysis from RGB values of lubricating oil images taken with a digital camera, and thus we designed and manufactured a Lubricating oil photographing equipment (Lope) for LIA. In this study, we investigated the relationship between color and pigment resulting from oxidation of lubricating oil by comparing RGB values by LIA to oxide production amount, residual rate of oxidation inhibitors and visible light absorption characteristics. As a result, we have shown that RGB values enable to monitor the pigments resulting from oxidation inhibitors. In other words, LIA makes it possible to indirectly monitor the residual rate of oxidation inhibitors easily and at a low cost, and thus LIA is expected to be used in the field for the lubricating oil analysis.

ZnDTP is used in lubricating oils as an antioxidant to inhibit oxidation. However, the use of ZnDTP has been discouraged because it contains phosphorus, which has a high environmental burden, and a new multifunctional additive is required. Fullerenes are attracting attention as a new multifunctional additive to replace ZnDTP. In the case that fullerene added oils are used in actual equipment, it is important to elucidate the mechanism by which fullerenes inhibit the autoxidation reaction of lubricating oils. In this study, we generated discharge in lubricating oils with different amounts of fullerenes to investigate the radical scavenging mechanism and the structural changes of fullerenes associated with it. As a result, the lubricating oils with fullerenes were found to exhibit antioxidant effect depending on the amounts of fullerenes. Additionally, the lubricating oils with fullerenes were discoloration with reaction, and the absorbance at a wavelength of 330 nm decreased. Also, SEM observation revealed particles ranging from sub µm to several µm in size in the oxidized fullerene added oil. These consequences reveal that it was clarified that the double bonds of the fullerenes were cleaved during the reaction and that they existed in the oil in an aggregated state.