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Mo-free 1.6-GPa bolt was developed for a Variable Compression Turbo (VC-Turbo) engine, which is environment friendly and improves fuel efficiency and output. Mo contributes to the improvement of delayed fracture resistance; therefore, the main objective is to achieve both high strength and delayed fracture resistance. Therefore, Si is added to the developed steel to achieve high strength and delayed fracture resistance. The delayed fracture tests were performed employing the Hc/He method. Hc is the limit of the diffusible hydrogen content without causing a delayed fracture under tightening, and He is the diffusible hydrogen content entering under a hydrogen-charging condition equivalent to the actual environment. The delayed fracture resistance is compared between the developed steel and the SCM440 utilized for 1.2-GPa class bolt as a representative of the current high-strength bolts.

During this decade, the constant increase and globalization of passenger car sales has led countries to adopt a common language for the treatment of CO2 and other pollutant emissions. In this regard, the WLTC - World-wide harmonized Light duty Test Cycle - stands as the new global reference cycle for fuel consumption, CO2 and pollutant emissions across the globe. Regulations keep a constant pressure on CO2 emission reduction leading vehicle manufacturers and component suppliers to modify hardware to ensure compliance. Within this balance, lubricants remain worthwhile contributors to lowering CO2 emission and fuel consumption. Yet with WTLC, new additional lubricant designs are likely to be required to ensure optimized friction due to its new cycle operating conditions, associated powertrain hardware and worldwide product use.

A new variable compression turbo (VC-Turbo) engine, which has a multi-link system for controlling the compression ratio from 8:1 to 14:1, requires high axial force for fastening the multi-links because of high input loads and the downsizing requirement. Therefore, it was necessary to develop a 1.6-GPa tensile strength bolt with plastic region tightening. One of the biggest technical concerns is delayed fracture. In this study, quenched and tempered alloy steels were chosen for the 1.6-GPa tensile strength bolt.

Wireless Power Transfer (WPT) promises automated and highly efficient charging of electric and plug-in-hybrid vehicles. As commercial development proceeds forward, the technical challenges of efficiency, interoperability, interference and safety are a primary focus for this industry. The SAE Vehicle Wireless Power and Alignment Taskforce published the Recommended Practice J2954 to help harmonize the first phase of high-power WPT technology development. SAE J2954 uses a performance-based approach to standardizing WPT by specifying ground and vehicle assembly coils to be used in a test stand (per Z-class) to validate performance, interoperability and safety. The main goal of this SAE J2954 bench testing campaign was to prove interoperability between WPT systems utilizing different coil magnetic topologies. This type of testing had not been done before on such a scale with real automaker and supplier systems.

There has been a growing need in recent years to further improve vehicle fuel efficiency and reduce CO2 emissions. JATCO began mass production of a transmission for rear-wheel-drive (RWD) hybrid vehicle with Nissan in 2010, which was followed by the development of a front-wheel-drive (FWD) hybrid system (JATCO CVT8 HYBRID) for use on a midsize SUV in the U.S. market. While various types of hybrid systems have been proposed, the FWD system adopts a one-motor two-clutch parallel hybrid topology which is also used on the RWD hybrid. This high-efficiency system incorporates a clutch for decoupling the transmission of power between the engine and the motor. The hybrid system was substantially downsized from that used on the RWD vehicle in order to mount it on the FWD vehicle. This paper describes various seal technologies developed for housing the dry multi-plate clutch inside the motor, which was a key packaging technology for achieving the FWD hybrid system.

A suitable GF-5 engine oil formulation is investigated to improve the fuel economy of gasoline engines with hydrogen-free DLC-coated valve lifters. Molybdenum dithocarbamate (MoDTC) is shown to be a suitable friction modifier for low viscosity grade engine oils like 0W-20. A suitable Ca salicylate detergent is also determined from several types examined for maximizing the friction reduction effects of MoDTC. The most suitable Ca salicylate has a chemical structure capable of forming a borophosphate glass film on metal surfaces, which is known to improve the effects of MoDTC. A high viscosity index Group III base oil (VI>140) is also effective in improving fuel efficiency. It is further clarified that the structural design of the polymethacrylate viscosity modifier is another important factor in reducing engine friction.

Reducing friction in the crankshaft main bearings is an effective means of improving the fuel efficiency of reciprocating internal combustion engines. To realize these improvements, it is necessary to understand the lubricating conditions, in particular the oil film pressure distributions between crankshaft and bearings. In this study, we developed a thin-film pressure sensor and applied it to the measurement of engine main bearing oil film pressure in a 4-cylinder, 2.5 L gasoline engine. This thin-film sensor is applied directly to the bearing surface by sputtering, allowing for measurement of oil film pressure without changing the shape and rigidity of the bearing. Moreover, the sensor material and shape were optimized to minimize influence from strain and temperature on the oil film pressure measurement. Measurements were performed at the No. 2 and 5 main bearings.

This paper describes the motor and inverter system developed for the Nissan LEAF that has been specifically designed as a mass-produced electric vehicle. The system produces maximum torque of 280 Nm and maximum power of 80 kW. The motor achieves a small size, high power, and high efficiency as a result of adopting the following in-house technologies. The magnetic circuit design was optimized for an interior magnet synchronous motor to attain the maximum performance figures noted here. The material technologies of the rotor and the stator facilitate high efficiency and the production technology achieves high density winding. The cooling mechanism is optimally designed for a mass-produced electric vehicle. The inverter incorporates the following original technologies and application-specific parts to obtain cost reductions combined with reliability improvements. The power module has an original structure with the power devices mounted directly on the busbars.

Hydraulic power steering is applied for petrol and diesel models of Infinity M series to provide supreme feeling of steering. Power assist of hydraulic power steering (here after called HPS), however, does not work when hybrid vehicle is in EV drive mode because the engine, which is the power source stops and the power is not supplied. Electric Power Steering (hereafter called EPS), therefore, “MUST” be installed to assist the power. Here comes the need that Nissan has developed our Hybrid EPS for Infinity M Hybrid model to keep providing supreme feeling of steering of hydraulic power steering without huge packaging change from the standard packaging of petrol & diesel models with hydraulic power steering. Our Hybrid EPS is the 1st hybrid EPS system in the world that is effectuated by oil pressure, and succesively realized by unique and excellent technology of Nissan.

This paper describes the new VK56VD engine, which was developed in response to growing demand for cleaner automobiles, better fuel economy, and improved engine performance. A 5.6 L V8 engine, the VK56VD will go into the new Infiniti M56 premium sport luxury sedan. To boost power and efficiency and lessen its environmental impact, this engine will utilize key technologies such as Continuous Variable Valve Event and Lift (VVEL) and Direct Injection Gasoline (DIG). Details of the VK56VD are presented here along with highlights of the applied technologies and the development means.

A new multiple dc-inputs direct electric-power converter (D-EPC) has been developed. It is placed between multiple dc power sources and an ac motor, eliminating the need for a dc/dc converter generally used in conventional converter/inverter systems. The D-PEC can improve the efficiency of the motor drive system with a more compact size. Its power distribution control is carried out by allotting voltage ratios to each of two different dc power sources on a time average basis. A new pulse-width-modulation (PWM) generation technique to drive switching devices in the D-EPC has also been developed. Tests have verified that the three-phase ac motor can be operated by controlling the power distribution between the two power sources.

Research is under way on an engine system [1] that achieves a variable compression ratio using a multiple-link mechanism between the crankshaft and pistons for the dual purpose of improving fuel economy and power output. At present, there is no database that allows direct judgment of the feasibility of the specific sliding parts in this mechanism. In this paper, the feasibility was examined by making a comparison with the sliding characteristics and material properties of conventional engine parts, for which databases exist, and using evaluation parameters based on mixed elasto-hydrodynamic (EHD) lubrication calculations. In addition, the innovations made to the mixed EHD calculation method used in this study to facilitate calculations under various lubrication conditions are also explained, including the treatment of surface roughness, wear progress and stiffness around the bearings.

This paper presents a new method for calculating optical flow using data from a high frame-rate camera. We focused on a feature of image data captured with a high frame-rate camera in which objects do not move more than one pixel between successive frames. This approach eliminates repetitive processing for object identification among frames taken at different sampling times. High-speed processing hardware architecture was designed with sequential processing only, and the algorithm was implemented in a field programmable gate array. The resultant unit can calculate optical flow for a 640×120 pixel size image with a 480-Hz processing cycle and 0.5-μsec processing latency.

This paper describes a low-cost 48 × 48 element thermal imaging camera intended for use in measuring the temperature in a car interior for advanced air conditioning systems. The compact camera measures 46 × 46 × 60 mm. It operates under a program stored in the central processing unit and can measure the interior temperature distribution with an accuracy of ±0.7°C in range from 0 to 40°C. The camera includes a thermoelectric focal plane array (FPA) housed in a low-cost vacuum-sealed package. The FPA is fabricated with the conventional IC manufacturing process and micromachining technology. The chip is 6.5 × 6.5 mm in size and achieves high sensitivity of 4,300 V/W, which is higher than the performance reported for any other thermopile. This high performance has been achieved by optimizing the sensor's thermal isolation structure and a precisely patterned Au-black absorber that attains high infrared absorptivity of more than 90%.

This paper presents a measurement technique to visualize the distribution of the in-cylinder mixture temperature and an experimental approach for analyzing the effect of the temperature distribution prior to ignition on homogeneous charge compression ignition (HCCI) combustion. First, a visualization technique for mixture temperature distribution based on the temperature dependence of laser induced fluorescence (LIF) was developed. As the next step, measurement of the temperature distribution was applied to an analysis of HCCI combustion. Controlled non-uniform temperature distributions in the mixture prior to ignition were generated by a special intake system with a completely divided intake port having separate electrical heaters.

Use of high strength steel (HSS) could be an important consideration in achieving competitive weight and safety performance of the body-in-white (BIW). This study covers key technical issues in the application development. Many aspects were studied such as formability, weldability and impact strength for application of this grade to the BIW. One of the key issues is spot weldability, especially in the assembly of heavy gauge materials for structural parts. The spot weld strength appears not to satisfy the target for some HSS applications, when hardness of the nugget is high. The relation between weld strength and the chemical composition of steel sheets was studied, because hardness can be controlled by chemical composition and welding conditions. It was found that using lower carbon content or carbon equivalent compared to conventional grades could improve weld strength.

This paper describes the improvement made to the high rigidity power-roller support structure in a dual-cavity half-toroidal CVT to further increase torque capacity. As a result of re-analyzing the function and parts composition of the previous structure, a high rigidity power-roller support structure, which permits power roller movement only in the horizontal direction, has been adopted. This structure enables the thrust and radial stiffness of the power-roller support to be substantially improved over the previous structure.

Improving the impact strength of the differential gears is one way to reduce the size and weight of the final drive unit. Previously, we developed high-strength steel for gear use by adding molybdenum and reducing impurities such as phosphorus and sulfur. However, additional improvement of impact strength is required these days due to higher engine torque and demands for further weight reductions. Toward that end, we focused on boron, which has been used as an element for improving hardenability, and analyzed what effect its addition would have on impact strength. Useful knowledge was obtained for improving impact strength through enhancement of grain boundary toughness. Various steels were then produced experimentally and used in gear strength tests. The results made it possible to improve impact strength while reducing the content of other alloys, resulting in the development of a chromium-molybdenum-boron case hardening steel with superior cold forgeabilty.

A plastic intake manifold has been developed for the new QR engine. This manifold has an intricate shape owing to its performance and layout requirements. The die slide injection (DSI) method was selected to manufacture this complicated shape using the world's first application of a common mold forming technique for a three-piece structure. This paper describes the manufacturing technology and the measures adopted to ensure the strength of welded parts, which is a key point of this method. The benefits obtained by applying this plastic intake manifold to the new engine are also described.

Hydrofrorming is an efficient forming process to produce automotive parts for reducing weight of cars. In order to reduce the period of development of hydrofoming parts, numerical simulation using FEM is applied to evaluate formability. A pipe needs to be bent before hydroforming for forming complicated shape parts. A pipe bending process is also necessary to FEM simulation. In this paper, a highly effective method to create a bent pipe FEM model based on geometrical changing between a pipe before and after bending is proposed. The widely used draw bending process is supposed to be applied. The method can construct the model in a short time. Therefore total computation time can be reduced drastically. The effects of number of integration points and elements to the computed results and springback prediction after bending are also investigated. The proposed method are applied to a actual part, the computed results are in good agreement with the experimental results.