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Silver metallic colors with thin and smooth aluminum flake pigments have been introduced for luxury brand OEMs. Regarding the paint formulation for these types of colors, low non-volatile(NV) and high aluminum flake pigment contents are known as technology for high metallic appearance designs. However, there are two technical concerns. First is mottling which is caused by uneven distribution of the aluminum flake pigments in paint film and second is poor film property due to high aluminum pigment concentration in paint film. Therefore, current paint systems have limitation of paint design. As a countermeasure for those two concerns, we had investigated cellulose nanofiber (CNF) dispersion liquid as both the coating binder and rheology control agent in a new type of waterborne paint system. CNF is an effective rheology control agent because it has strong hydrogen bonds with other fiber surfaces in waterborne paint.

From the point of global and local environment, internal combustion engine is facing the need for significant improvement of exhaust emission. Especially, important is the reduction of unburned hydrocarbon (HC) from fuel film on liner under cold condition. In this study, at first, quantitative fuel film measurement technique by using Laser Induced Exciplex Fluorescence (LIEF) was developed. For the light source, 4th harmonic pulse yttrium aluminum garnet (YAG) laser (266nm) was used. For the tracer, the combination of N,N-Dimethylaniline (DMA) and naphthalene was used and quantitative concentration was decided by calibration test. With LIEF, the distribution of fuel film can be obtained by measuring the fluorescence only from the liquid phase. In order to evaluate the effect of fuel film on exhaust HC emission from engine, the film distribution was measured using quartz glass liner. For the injector, a prototype 6-hole gasoline injector was used.

In order to achieve the Toyota Environmental Challenge of 2050 (zero CO2 emissions), we have developed an innovative coating system that achieves more than 95% transfer efficiency. In order to reduce paint loss in the painting process, it is necessary to eliminate overdust and bounce dust. The most important point is how to spray (atomization, particle flight, adhesion) without shaping air. We have developed a “super high transfer efficiency system” that eliminates the need for shaping air. We continue to challenge the development of innovative technologies to view the paint shop as clean and eco-friendly environment.

When the air conditioning (A/C) is turned on, the intake air to the HVAC is cooled at the evaporator. This is not only used for cooling the air temperature but also to dehumidify. Therefore, for a typical automatic climate control system, A/C will automatically operate even in winter (cold ambient temperature conditions) in order to prevent the windows from fogging despite its effect on fuel economy. In some applications, a humidity sensor is installed on top of the windshield and when the probability of fogging is low the A/C operation is disabled automatically to prevent unnecessary compressor operation which can increase fuel consumption. However, humidity sensor is not widely adopted as it requires some space to be installed and the cost is relatively expensive compared with other HVAC equipped sensors. In this study, a system was invented that disables the compressor operation when the fogging probability is low without using the conventional humidity sensor.

Fuel economy and emission regulations for Light-duty Trucks (LDT) are becoming increasingly restrictive year by year. At the same time, Mid-size SUV demands are increasing all over the world. The advancement of Toyota Hybrid System (THS) aims to meet increasingly strict fuel economy regulations and rapidly advance vehicle technologies to meet electrification goals by 2050 (Figure 1). Toyota has been committed to the evolution of hybrid technology starting with the first Prius in 1997 and continues to develop industry leading electrification technologies. The updated hybrid system for the brand-new Highlander was developed to meet worldwide regulations and have competitive class leading fuel economy with an affordable price. This technology is necessary not only to anticipate expanding SUV sales around the world, but to also keep environmental impact to a minimum.

Further improvements in catalyst performance are required to help protect the atmospheric environment. However, from the viewpoint of resource availability, it is also necessary to decrease the amount of precious metals used at the active sites of the catalyst. Therefore, a high-performance three-way catalyst with an advanced coating layer has been developed to lower the amount of precious metal usage. Fuel efficiency improvement technologies such as high compression ratios and a large-volume exhaust gas recirculation (EGR) generally tend to increase the ratio of hydrocarbons (HC) to nitrogen oxides (NOx) in exhaust gas. This research focused on the palladium (Pd) loading depth in the coating layer with the aim of improving the hydrocarbon (HC) conversion activity of the catalyst.

As part of efforts to address climate change and improve energy security, researchers have improved the thermal efficiency of engines by expanding the lean combustion limit. To further expand the lean combustion limit, the authors focused not only on engine technology but the chemical reactivity of various fuel molecules. Furan and anisole were among the fuel molecules selected, based on the idea that promising candidates should enhance the flame propagation speed and have good knocking resistance. Engine testing showed that the lean limit can be expanded by using fuels with the right molecular structures, resulting in higher thermal efficiency.

To correspond to the social requirements such as climate change, air pollution, and energy security, enhancing the engine thermal efficiency is strongly required in these days. As for the specific engine technologies to improve the engine thermal efficiency, Atkinson cycle, cooled EGR (Exhaust Gas Recirculation), and low friction technologies have been developed [1–4]. In regard to combustion technology, lean boosted concept has a potential to reduce CO2 emission because lean boosted concept is expected to enhance the engine thermal efficiency. Although expanding lean combustion limit is important for both increasing the engine thermal efficiency and reducing NOx emission, there is a limitation to realize stable lean combustion with SI (Spark Ignition) gasoline engine. In this study, fuel effects on the combustion characteristics from the viewpoint of chemical reaction capability are focused on.

Numerical modeling of engine combustion products requires detailed chemistry and therefore large computational resources and time. This becomes a constraint when engine optimization at system level is desired. In this paper, a 1D modeling approach is proposed for fast computation to predict emission level at various engine running conditions. A new chemical solver within 1D framework is developed along with suitable reduced chemical mechanism. The reduced reaction scheme is validated against detailed chemistry on 0D and 1D reactors. It is confirmed that the new fast 1D solver achieves more than 100X speed improvement. Now larger mechanisms can be used for better accuracy with reasonable turnaround time. This methodology allows virtual engine emission map generation, with a refined emission map completed within 12 hours of computational time.

The knock-suppression effectiveness of exhaust-gas recirculation (EGR) can vary between implementations that take EGR gases after the three-way catalyst and those that use pre-catalyst EGR gases. A main difference between pre-and post-catalyst EGR gases is the level of trace species like NO, UHC, CO and H2. To quantify the role of NO, this experiment-based study employs NO-seeding in the intake tract for select combinations of fuel types and compression ratios, using simulated post-catalyst EGR gases as the diluent. The four investigated gasoline fuels share a common RON of 98, but vary in octane sensitivity and composition. To enable probing effects of near-zero NO levels, a skip-firing operating strategy is developed whereby the residual gases, which contain trace species like NO, are purged from the combustion chamber. Overall, the effects of NO-seeding on knock are consistent with the differences in knock limits for preand post-catalyst EGR gases.

This paper presents the thermal management of a hybrid vehicle (HV) using a heat pump system in cold weather. One advantage of an HV is the high efficiency of the vehicle system provided by the coupling and optimal control of an electric motor and an engine. However, in a conventional HV, fuel economy degradation is observed in cold weather because delivering heat to the passenger cabin using the engine results in a reduced efficiency of the vehicle system. In this study, a heat pump, combined with an engine, was used for thermal management to decrease fuel economy degradation. The heat pump is equipped with an electrically driven compressor that pumps ambient heat into a water-cooled condenser. The heat generated by the engine and the heat pump is delivered to the engine and the passenger cabin because the engine needs to warm up quickly to reduce emissions and the cabin needs heat to provide thermal comfort.

Vehicle weight reduction is becoming more and more important as increasingly stringent fuel economy regulations are introduced around the world. This development improved the hydraulic gear pump performance of the next-generation Active Height Control (AHC) suspension and achieved significant weight reduction of 5 kg by eliminating the auxiliary pump accumulator. To realize the necessary high-pressure with a high flow rate, the sealing performance of the pump at the tips of the gear teeth is very important. This was achieved by developing “breaking-in” technology that shaves away the aluminum housing using the gear teeth and creates zero clearance between the teeth tips and the housing. To reduce the frictional loss torque of the pump, which was identified as an issue of this technology, it was necessary to completely shave away the initial clearance in the breaking-in process.

Exhaust gas recirculation (EGR) can be used to mitigate knock in SI engines. However, experiments have shown that the effectiveness of various EGR constituents to suppress knock varies with fuel type and compression ratio (CR). To understand some of the underlying mechanisms by which fuel composition, octane sensitivity (S), and CR affect the knock-mitigation effectiveness of EGR constituents, the current paper presents results from a chemical-kinetics modeling study. The numerical study was conducted with CHEMKIN, imposing experimentally acquired pressure traces on a closed reactor model. Simulated conditions include combinations of three RON-98 (Research Octane Number) fuels with two octane sensitivities and distinctive compositions, three EGR diluents, and two CRs (12:1 and 10:1). The experimental results point to the important role of thermal stratification in the end-gas to smooth peak heat-release rate (HRR) and prevent acoustic noise.

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.

Plugin hybrid electric vehicles (PHEVs) have several attractive features in terms of reduction of greenhouse gas (GHG) emissions. Compared to conventional vehicles (CVs) that only have an internal combustion engine (ICE), PHEVs have better energy efficiency like regular hybrids (HEVs), allow for electrifying an appreciable portion of traveled miles, and have no range anxiety issues like battery-only electric vehicles (BEVs). However, in terms of criteria emissions (e.g., NOx, NMOG, HC), it is unclear if PHEVs are any better than HEVs or CVs. Unlike GHG emissions, criteria emissions are not continuously emitted in proportional quantities to fossil fuel consumption. Rather, the amount and type of criteria emissions is a rather complex function of many factors, including type of fuel, ICE temperature, speed and torque, catalyst temperature, as well as the ICE controls (e.g., fuel-to-air ratio, valve and ignition timing).

Environmental awareness has increased on a global scale which pushed for a heavier demand for weight reduction and high transmission efficiency on manual transmissions (hereafter referred to as the “MT”) in improving vehicle driving and fuel economy performance. Comfortable shift feel is also continuously in demand by the customer because its sensitive performance can be directly recognized by the driver which may determine the transmission’s merchantability. The newly developed 6-speed MT (hereafter referred to as the “6MT”) has achieved size reduction (compact size), weight reduced, better fuel efficiency, and improvement in the shift feel which will continue to maintain its’ competitiveness in the future.

To resolve two major problems of conventional CFD-based shape optimization technology: (1) dependence of the outcome on the selection of design parameters, and (2) high computational costs, two types of innovative inverse analysis technologies based on a mathematical theory called the Adjoint Method were developed in previous studies for maximizing an arbitrary hydrodynamic performance aspect as the cost function: surface geometry deformation sensitivity analysis to identify the locations to be modified, and topology optimization to generate an optimal shape. Furthermore, these technologies were extended to transient flows by the application of the transient Adjoint Method theory. However, there are many cases around flow path shapes in vehicles where performance with respect to heat or concentration, such as the total amount of heat transfer or the flow rate of a specific gas component, is very important.

Awareness of environmental protection with respect to the particulate number (PN) in the exhaust emissions of gasoline direct injection (GDI) engine vehicles has increased. In order to decrease the emission of particulate matter (PM), suppressing emissions by improving engine combustion, and/or filtering PM with a gasoline particulate filter (GPF) is effective. This paper describes the improvement of the coated GPF to reduce pressure drop while securing three-way performance and PN filtration efficiency. It was necessary to load a certain amount of washcoat on the GPF to add the three-way function, but this led to an increase in pressure drop that affected engine power. The pressure drop was influenced by the gas permeation properties of the filter wall.

For the purpose of coping with the strengthening of NOx exhaust gas control and fuel consumption control, it is indispensable to improve the NOx purification capacity. In view of this, vehicle manufacturers are in the course of developing high performance SCR (Selective Catalytic Reduction) systems [1, 2]. For such SCR systems to be realized, high precision NOx sensors for carrying out urea injection quantity control and SCR degradation diagnosis are absolutely indispensable. Detection of NOx concentration by means of a NOx sensor is generally performed as follows: O2 is discharged by means of an O2 detection electrode; remaining NOx is decomposed by a NOx detection electrode; NOx concentration is then detected as electric current that flows when oxygen ions are conduct through solid electrolyte. In order to detect NOx of ppm-order, it is necessary to detect minute current of nA-order with high accuracy.

Growing concerns about the depletion of raw materials as vehicle ownership continues to increase is prompting automakers to look for ways of decreasing the use of platinum-group metals (PGMs) in the exhaust systems. This research has developed a new catalyst with strong robustness against fluctuations in the exhaust gas and excellent nitrogen oxide (NOx) conversion performance. One of the key technologies is a new OSC material that has low surface area (SA) and high OSC performance. We enhanced the pyrochlore- ceria/zirconia (CZ) which has a very small SA. In order to enhance the heat resistance and promote the OSC reaction, we selected and optimized the additive element. This material showed high OSC performance especially in the temperature range of 400 degrees or less. Another key technology is washcoat structure that has high gas diffusivity by making connected pore in the washcoat (New pore forming technology).