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To prevent global warming, further reductions in carbon dioxide are required. It is therefore important to promote the spread of electric vehicles powered by internal combustion engines and electric vehicles without internal combustion engines. As a result, emissions from hybrid electric vehicles equipped with internal combustion engines should be further reduced. Interest in catalytic reactions in an electric field with a higher catalytic activity compared to conventional catalysts has increased because this technology consumes less energy than other electrical heating devices. This study was therefore undertaken to apply a catalytic reaction in an electric field to an exhaust emission control. First, the original experimental equipment was built with a high voltage system used to conduct catalytic activity tests.

Our L2-automated driving system enabling a driver to take his/her hands off from the steering wheel is self-operating on a highway, allowing the vehicle to automatically change lanes and overtake slow-speed leading vehicles. It includes an OTA function, which can extend the ODD after the market launch. To realize these features in reasonably safer and more reliable ways, system architecture must be designed well under hardware and software implementation constraints. One such major constraint is the system must be designed to make the most out of the existing sensor configuration on the vehicle, where five peripheral radars and a front camera for ADAS as well as panoramic-view and rear-view cameras for monitoring are available. In addition, four LiDARs and a telephoto camera are newly adopted for ADS. Another constraint is the system must consist of reliable redundant components for fail-safe operation.

Toyota Motor Corporation has been actively pursuing the development of fuel cell vehicles (FCVs) to respond to global environmental concerns and demands for clean energy. Toyota developed the first fuel cell (FC) bus to receive vehicle type certification in Japan. Subsequently, a new FC bus has been developed, which adopts two FC systems and four high-voltage batteries to achieve the required high power performance and durability. For enhanced durability, the FC system is controlled to maximize usage of the high-voltage batteries and to reduce the number of electric potential changes of the fuel cell. To accomplish this, the voltage of the FC stack must be kept high and FC power must be kept low. The high-voltage batteries were used to actively minimize FC power during acceleration.

This report describes the implementation of the spark channel short circuit and blow-out submodels, which were described in the previous report, into a spark ignition model. The spark channel which is modeled by a particle series is elongated by moving individual spark particles along local gas flows. The equation of the spark channel resistance developed by Kim et al. is modified in order to describe the behavior of the current and the voltage in high flow velocity conditions and implemented into the electrical circuit model of the electrical inductive system of the spark plug. Input parameters of the circuit model are the following: initial discharge energy, inductance, internal resistance and capacitance of the spark plug, and the spark channel length obtained by the spark channel model. The instantaneous discharge current and the voltage are obtained as outputs of the circuit model.

Improving the engine efficiency to respond to climate change and energy security issues is strongly required. In order to improve the engine efficiency, lower fuel consumption, and enhance engine performance, OEMs have been developing high compression ratio engines and downsized turbocharged engines. However, higher compression ratio and turbocharging cause cylinder pressure to increase, which in turn increases the demand voltage for ignition. To reduce the demand voltage, a new ignition system is developed that uses a high voltage Zener diode to maintain a constant output voltage. Maintaining a constant voltage higher than the static breakdown voltage helps limit the amount of overshoot produced during the spark event. This allows discharge to occur at a lower demand voltage than with conventional spark ignition systems. The results show that the maximum reduction in demand voltage is 3.5 kV when the engine is operated at 2800 rpm and 2.6 MPa break mean effective pressure.

An unprecedented phenomenon that achieves high NOx conversion was found over an NSR catalyst. This phenomenon occurs when continuous short cycle injections of hydrocarbons (HCs) are supplied at a predetermined concentration in lean conditions. Furthermore, this phenomenon has a wider range of applicability for different catalyst temperatures (up to 800 degrees Celsius) and SVs, and for extending thermal and sulfur durability than a conventional NOx storage and reduction system. This paper analyzes the reaction mechanism and concludes it to be highly active HC-deNOx by intermediates generated from adsorbed NOx over the base catalysts and HCs partially oxidized by oscillated HC injection. Subsequently, a high performance deNOx system named Di-Air (diesel NOx aftertreatment by adsorbed intermediate reductants) was demonstrated that applies this concept to high speed driving cycles.

In conventional gasoline engine vehicles, three-way catalysts are used to simultaneously remove HC, CO and NOx from the exhaust gas. The effectiveness of the catalyst to remove these harmful species depends strongly on the oxygen concentration in the exhaust gas. Deterioration of three-way catalyst results in a reduction in its purification activity and OSC (oxygen storage capacity). In this investigation, additive elements were used to enhance the durability and OSC of the catalyst support material. An optimized formulation of a CeO2-ZrO2 and a ZrO2 material was developed to have excellent durability, improved OSC, enhanced interaction between precious metals and support materials, and increase thermal stability. Using these newly developed support materials, catalysts with increased performance was designed.

In order to further improve the performance of NOx storage-reduction catalysts (NSR catalysts), focus was placed on their high temperature performance deterioration via sulfur poisoning and heat deterioration. The reactions between the basicity or acidity of supports and the storage element, potassium, were analyzed. It was determined that the high temperature performance of NSR catalysts is enhanced by the interaction between potassium and zirconia, which is a basic metal oxide. Also, a new zirconia-titania complex metal oxides was developed to improve high temperature performance and to promote the desorption of sulfur from the supports after aging.

Two effects of rich-spike duration on NOx-storing have been analyzed. The first one, that NOx-storing speed decreases as rich-spike duration increases, is explained as the influence of NOx diffusion in wash-coat layer, which is quantified by a simple mathematical expression for NOx-storing rate. The second one, a peculiar behavior of NOx-storing in appearance of the outlet NOx concentration, is clarified: Heat produced directly or indirectly (via oxygen storage in ceria) by rich-spike warms up the downstream part, which releases excess NOx at the raised temperature. Contributions of the oxygen storage and the carbonate of NOx-storage material are also discussed.

A new 3-way catalyst with NOx conversion performance for lean-burn engines has been developed. The catalyst oxidizes NOx and stores the resulting nitrate, which is then reduced by HC and CO during engine operation around the stoichiometric air/fuel ratio. Both the composition of the storage component and the particle sizes of the noble metal were optimized. In addition, a special air fuel mixture control has been developed to make the best of the NOx storage-reduction function. The present catalyst showed 90% conversion efficiency and improved fuel economy by 4% in the Japanese 10-15 mode test cycle. The efficiency remained at 60% or more after durability test.

In Toyota, a robot off-line programming system was developed five years ago for the use at spot welding processes. And it has been effective to reduce and level off the engineering time. This time we have developed the new robot simulation system. It has three newly features so that the system becomes capable of simulating and programming robots from various manufacturers with different functions. As a result, the new system can be applied to a variety of processes in automobile manufacturing. First, a universal robot programming language was developed which includes a variety of commands such as definitions of motion attributes, signals of inputs/outputs, control of program flow, special functions proper to each process, and so on. And the language can be translated to and from any particular programming language using pre / post processor, so the simulation system needs to deal with only one language.

The higher compression ratio engines, two-stroke engines and flexible fuel vehicles currently under development tend to face the problems of spark plug fouling owing to the necessity of using cold type spark plugs. This paper analyzes the sparking of fouled spark plugs and investigates the characteristics required of an ignition system in order to avoid fouling problems. The results clearly establish that to maintain a strong spark even when the plug is fouled, a high voltage should be instantaneously applied to the spark plug. A series-gap on the high-tension side was confirmed to be an effective means of achieving this and a new plug cap provided with a series-gap has resolved fouling problems such as failure to start. Lately, fuel economy and long-term energy conservation have become critically important. For automobiles, higher compression ratio engines, two-stroke engines and flexible fuel vehicles (FFVs) are being developed.

Electronic Control Units (ECUs) for automobiles are usually composed of a main single-chip microcomputer and peripheral circuits with some standard and/or custom ICs. The peripheral circuits vary with the kinds of control or models of automobiles. When the peripheral circuits are replaced with a single-chip microcomputer, the ECU becomes compact and low in cost. This is because the ECU is constructed with only two LSIs and can be used for various kinds of control and various models of automobiles only by changing the program of the microcomputer. The microcomputer, however, requires many I/O functions and high reliability. We have developed a new 4-bit microcomputer suitable for these requirements. The new microcomputer has two remarkable features. One is powerful I/O functions such as high speed I/O, serial I/O, parallel I/O, analog I/O, and default output that is generated in place of the calculated output by the main CPU when it fails.

This paper contains an explanation of a Multiplex Wiring System with Optical Data-Link for cars, which has been installed in the Toyota “Century” since 1982. In this system, a total of 64 signals related to door wiring are transmitted in a multiplex fashion, and the number of wires from the front right-hand door to the interior could be reduced from 46 wires, which were used with conventional wiring techniques, to 10 wires including 2 plastic optical fibers. This system also has various control functions which includes a door-lock control function. In order to give high reliability to this system, we have developed a new optical data-link as well as a new custom micro-computer. And in the automobile industry, such a large scale multiplex wiring system having high reliability is very innovative in our opinion and will surely have a large impact in the future.