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The environment is one of the most important issues currently facing the world and the automobile industry is required to respond with eco-cars. To meet this requirement, the hybrid vehicle is one of the most optimal solutions. The hybrid system automatically stops engine idling (idling stop), or stops the engine during deceleration to recover energy. The engine stop however creates a problem concerning the vehicle's climate control system. Because the conventional climate control system incorporates a compressor driven by engine belt, there is almost no cooling performance while the engine is stopped. Until now, when a driver needed more cooling comfort the engine has been switched back on as a compromise measure. To realize cabin comfort that is consistent with fuel saving, a 2-way driven compressor has been developed that can be driven both by engine belt while the engine is running and by electric motor when the engine is stopped.

Natural gas homogeneous charge compression ignition (HCCI) engines require high compression ratios and intake air heating because of the high auto-ignition temperature of natural gas. In the first study, the natural gas fueled HCCI combustion with internal exhaust gas recirculation (EGR) was achieved without an intake air heater. The effects of the combustion chamber configuration, turbocharging, and external EGR were investigated for expanding the operating range. As a result, it was cleared that the combination of internal / external EGR and turbocharging is effective for expanding the HCCI operational range toward high loads. Meanwhile, the HCCI combustion characteristics at high engine speeds were unstable because of an insufficient reaction time for auto-ignition. Although the engine operation with a richer air-fuel ratio was effective for improving the combustion stability, the combustion noise (CN) was at an unacceptable level.

There is increasing demand for highly functional diesel engine turbochargers capable of meeting Euro 6 emissions regulations while improving dynamic performance and fuel economy. However, since these requirements cannot be easily satisfied through refinements of existing technology, Toyota Motor Corporation has developed the new D-series turbocharger for initial installation in its GD diesel engine. The higher efficiency and wider operation range of the new turbocharger enabled the amount of the turbine flow capacity to be reduced by 30%, while helping to improve dynamic response and fuel economy. The mechanism causing the generation of fuel deposits in the fuel injection system upstream of the turbocharger, which was adopted for compliance with emissions regulations, was analyzed and fundamental countermeasures were applied. The result is a new highly functional turbocharger with greatly enhanced reliability.

Toyota Motor Corporation aims to develop vehicles that are both fun to drive and fuel efficient, using highly reliable, low cost, and fundamental technology. This approach focuses on the accumulation of incremental improvements to combustion characteristics and friction, making the best use of the maximum potential of the displacement of a new 2.0-liter fuel-efficient diesel engine. This new engine has been launched in several markets around the world for the Avensis, the Auris, the RAV4, and the Verso since November of 2011. This paper presents an outline of this new engine and its technology.

Toyota is implementing various technical developments in various fields for protection of environment. Reducing the fuel consumption is a matter of great urgency for the reduction of CO2 emissions. In the technology of vehicle body development, mass reduction and the improvement of aerodynamics are mainly important for fuel economy. As the one of way for this, we adopted resin glass as the back door glass of ES3, small-sized low-fuel consumption vehicle. (Figure 1,2,3) The first advantage of resin glass is the low density that weights about a half of inorganic glass. However resin glass is needed higher thickness for equivalent rigidity, as the result approximately 41% mass reduction was achieved. However resin glass is relatively expensive. Therefore it seems to be difficult to expand the usage of resin for this application. Then, we focused on additional advantage of resin glass, in order to make good use of resin glass. The second advantage of resin glass is design flexibility.

A new concept, Diesel Staggered Premixed Ignition with Accelerated oxidation (D-SPIA) was developed for lower exhaust emissions and carbon dioxide (CO₂) and this is based on divided fuel injection before top dead center (TDC). D-SPIA is a result of investigating various diesel combustion methods. Although the D-SPIA is a type of Premixed Charge Compression Ignition (PCCI), it has a distinct feature of double premixed combustion by optimum injection quantities and staggered timing, which can achieve an ideal heat release rate for low pollutant emissions and fuel consumption. Based on this concept, second injection timing and the proportion of the second fuel injection quantity play significant roles to reduce smoke, and hydrocarbon (HC) and carbon monoxide (CO) emissions. The second injection timing has a close relation to the premixed time of the second fuel injection and smoke level.

High-pressure metal hydride (MH) tank has been designed based on a 35 MPa cylinder vessel. The heat exchanger module is integrated into the tank. Its advantage over high-pressure cylinder vessels is its large hydrogen storage capacity, for example 9.5 kg with a tank volume of 180 L by Ti25Cr50V20Mo5 alloy. Cruising range is about 900 km, over 3 times longer than that of a 35 MPa cylinder vessel system with the same volume. The hydrogen-charging rate of this system is equal to the 35 MPa cylinders without any external cooling facility. And release of hydrogen at 243 K is enabled due to the use of hydrogen-absorbing alloy with high-dissociation pressure, for example Ti35Cr34Mn31 alloy.

Inverter type electric compressors capable of providing cooling capability during engine stop and that do not cause fuel efficiency drop during air conditioning system use are recently being used in hybrid vehicles that have been drawing attention for their low fuel consumption and low emissions. Conventionally, the electric compressor inverter, like other high-voltage devices, was located in a cooling unit known as a power control unit (PCU) box because it requires cooling. However, inverter installation in the PCU box is subject to rigid installation constraints, and there is increasing need to integrate it with the electric compressors. In the present development, we adopted inverter-integrated construction in which the inverter is cooled using suction refrigerant etc., so as to make the electric compressor compact.

A new clean diesel combustion concept has been proposed and its excellent performance with respect to gas emissions and fuel economy were demonstrated using a single cylinder diesel engine. It features the following three items: (1) low-penetrating and highly dispersed spray using a specially designed injector with very small and numerous orifices, (2) a lower compression ratio, and (3) drastically restricted in-cylinder flow by means of very low swirl ports and a lip-less shallow dish type piston cavity. Item (1) creates a more homogeneous air-fuel mixture with early fuel injection timings, while preventing wall wetting, i.e., impingement of the spray onto the wall. In other words, this spray is suitable for premixed charge compression ignition (PCCI) operation, and can decrease both nitrogen oxides (NOx) and soot considerably when the utilization range of PCCI is maximized.

In PCCI combustion with multiple injections, the mechanism having two heat release peaks which has a favorable characteristic of reducing noise is studied using numerical tool of single- and also multi-zone model of CHEMKIN PRO. In the present investigation, the physical issues, such as variations in the equivalent ratio and temperature caused by the fuel injection are simplified first so that the key issues of chemical reaction occurred in the combustion chamber can be extracted and are discussed in detail. The results show that the interval of two heat-release peaks can be controlled and as the number of zones of the calculation increases, the change in the timing of a heat release peak is increased but over three-zones, it is not affected any more. This indicates that to study about complex diesel combustion phenomena, three-to four-zone model shall give sufficiently accurate results.

The stratification feature of DI gasoline combustion was studied by using a constant volume combustion vessel. An index of stratification degree, defined as volumetric burning velocity, has been proposed based on the thermodynamic analysis of the indicated pressure data. The burning feature analysis using this stratification degree and the fuel vapor concentration measurement using He-Ne laser ray absorption method were carried out for the swirl nozzle spray with 90° cone angle and the slit nozzle spray with 60° fan angle. Ambient pressure and ambient temperature were changed from atmospheric condition to 0.5∼0.6 MPa and 465 K, respectively. Air Swirl with swirl ratio of 0∼1.0 were added for the 90° swirl nozzle spray. Single component fuels with different volatility and self-ignitability from each other were used besides gasoline fuel. The major findings are as follows. High ambient temperature improves stratification degree due to the enhanced fuel vaporization and vapor diffusion.

The aim of this research is to develop the diesel combustion simulation (UniDES: Universal Diesel Engine Simulator) that incorporates multiple-injection strategies and in-cylinder composition changes due to exhaust gas recirculation (EGR), and that is capable of high speed calculation. The model is based on a zero-dimensional (0D) cycle simulation, and represents a multiple-injection strategy using a multi-zone model and inhomogeneity using a probability density function (PDF) model. Therefore, the 0D cycle simulation also enables both high accuracy and high speed. This research considers application to actual development. To expand the applicability of the simulation, a model that accurately estimates nozzle sac pressure with various injection quantities and common rail pressures, a model that accounts for the effects of adjacent spray interaction, and a model that considers the NOx reduction phenomenon under high load conditions were added.