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For reduction of fuel consumption, a new device “Water Jacket Spacer” which improves temperature distribution of a cylinder block bore wall was developed. In the case of a conventional cylinder block, coolant flow concentrates at the bottom and middle region of the water jacket. While temperature of the upper bore wall is high (due to high-temperature combustion gas) the temperature of the lower bore wall is low, since its only function is to support the piston. When the developed spacer is inserted into a water jacket, the coolant flow concentrates at the upper part of the jacket. As a result, cooling ability to the upper bore wall was improved and temperature of lower bore wall was increased, thereby reducing fuel consumption.

A prototype power control unit (PCU) was manufactured using silicon carbide (SiC) power semiconductors (diodes and transistors), which have low power loss when switching on and off. This PCU was installed in a hybrid vehicle (HV) and driven on a test course and chassis dynamometer. The test results confirmed a fuel efficiency improvement of about 5 percent.

In order to reduce engine development timing and cost, a numerical calculation has been developed by Toyota Motor Company and Toyota Technical Center to evaluate valve train systems. The goal is to predict valve_bounce speed, valve displacement, hydraulic lash adjuster motion and strain in the rocker arm. The numerical procedure combines finite element model and multi-body dynamic analysis. Normally, strain calculation is a two-step process. In the first step, engineers obtain the excitation from the dynamic analysis. In the second step, engineers use the forcing function from dynamic analysis to calculate strain and stress. The new approach in this paper, using ADAMS, calculates dynamic load and recover strain simultaneously. As the flexibility of the moving part (for example rocker arm) is taken into account in the equations of motion, ADAMS will calculate the modal strain. Based on the modal strain, the strain or stress at any given node(s) can be recovered.

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.

Engine oils and their additives are formulated to meet required performance areas such as lubrication, detergency, dispersancy, anti-wear, and so on. Understanding degradation of engine oil additives is important to formulate oils with long time durability. Engine oil additives have been found to affect abnormal combustion in turbocharged gasoline direct injection (TGDI) engines, called low speed pre-ignition (LSPI). Some of metal containing additives such as zinc dithiophosphates (ZnDTP) and molybdenum dithiocarbamates (MoDTC) have been found to reduce LSPI events. In this study, we investigated degradation of ZnDTP and MoDTC in gasoline engine operation and effects of the degradation on LSPI performance.

Phosphor thermometry was used during fuel injection in an optical engine with the glass piston of reentrant type. SiO2 coated phosphor particle was used for the gas-phase temperature measurements, which gave much less background signal. The measurements were performed in motored mode, in combustion mode with injection of n-heptane and in non-combustion mode with injection of iso-octane. In the beginning of injection period, the mean temperature of each injection cases was lower than that of the motored case, and temperature of iso-octane injection cases was even lower than that of n-heptane injection cases. This indicates, even if vaporization effect seemed to be the same at both injection cases, the effect of temperature decrease changed due to the chemical reaction effect for the n-heptane cases. Chemical reaction seems to be initiated outside of the fuel liquid spray and the position was moving towards the fuel rich area as the time proceeds.

New engine controls have been developed for the turbocharged Lexus NX200t to improve driving power by reducing engine torque output lag. Drive power management functions have been centralized in an integrated drive power control system. The newly developed controls minimize the potential reduction in drivability associated with the adoption of a turbocharged engine while improving fuel efficiency. General driveability issues commonly associated with a turbocharged engine include sudden increases in drive power due to the response lag of the turbocharger, and higher shifting frequencies if this response lag triggers a disturbed accelerator operation pattern by the driver. The developed technologies detect and control sudden increases in drive power to create the optimum drive power map, and reduce unnecessary shifts even if the driver's accelerator operation is disturbed.

Newly developed 2VZ-FE engine for CAMRY is a 2.5-liter water cooled and V-type 6-cylinder engine exported from TOYOTA for the first time. This engine has the TOYOTA original 4-valve DOHC system. That is, exhaust camshafts driven by intake camshafts using scissors gears. By its compact configuration with the gear driven camshafts, this V-type 6-cylinder engine is mounted on a front-wheel-drive vehicle which originally had an in-line 4-cylinder engine. By increasing IVZ-FE engine displacement (for domestic), compact pentroof-type combustion chambers, optimum air-fuel ratio and ignition timing by TCCS (TOYOTA Computer Controlled System) and other technologies, a high performance 153HP/5600rpm and a large torque 155ft·lbs/4400rpm have been achieved with a low fuel consumption.

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.

This paper proposes a theory to analyze the collision avoidance capability of automated driving technologies. The theory gives answers to a fundamental question whether automated vehicles fall into extreme conditions at all rather than another question how a vehicle reacts under extreme conditions (is it as safe as driver?). The theory clarifies the following matters: There are two types of hazards to cause collisions, cognitive hazards and behavioral hazards. Cognitive hazards are handled by controlling the upper limit speed of the automated vehicle including when stopped. There are two methods for handling behavioral hazards, preparation and response. The response known well is the coping method activated when the hazard is detected in the dynamic (operational) level. The preparation is the coping method operating at all time in the semantic (tactical) level.

1 Recently, demand for small-bore compact vehicle engines has been increasing from the standpoint of further reducing CO2 emissions. The generalization and formulation of combustion processes, including those related to emissions formation, based on a certain similarity of physical phenomena regardless of engine size, would be extremely beneficial for the unification of development processes for various sizes of engines. The objective of this study is to clarify what constraints are necessary for engine/nozzle specifications and injection conditions to achieve the same combustion characteristics (such as heat release rate and emissions) in diesel engines with different bore sizes.

The engine in the new fourth generation Prius carries over the same basic structure as the 2ZR-FXE used in the third generation and incorporates various refinements to enhance fuel efficiency. Called the ESTEC 2ZR-FXE, the new engine incorporates various fuel efficient technologies to improve combustion characteristics, knocking, and heat management, while also reducing friction. As a result of this meticulous approach to enhancing fuel efficiency, the new engine is the first gasoline engine in the world to achieve a maximum thermal efficiency of 40%. This paper describes the fuel efficient technologies incorporated into this engine.

Methylcyclopentadienyl manganese tricarbonyl (MMT) is used as an octane-enhancing metallic additive for unleaded gasoline which can prevent engine knock by proactive reaction with the hydrocarbon free radicals before starting the auto-ignition of hydrocarbons. However it has been pointed out that MMT causes automotive catalysts clogging and spark plug severely fouling. Therefore, many countries have fuel standards that prohibit or limit the usage of MMT. Nevertheless, some countries still use MMT as there are no restrictions imposed by fuel standards. As mentioned in several papers, metallic additives of engine oil such as calcium cause an abnormal combustion phenomenon called low-speed pre-ignition (LSPI) in turbocharged spark ignition engines. In contrast, the effect of metallic additives of gasoline such as MMT on LSPI has not been studied.

In 2007, researchers at the Massachusetts Institute of Technology successfully completed a Wireless Power Transfer (WPT) experiment. Ever since, interest in WPT has been growing. At Toyota, we have been developing the underlying technology of a WPT system. Simultaneously we have been working with regulatory committees to create a standard for WPT. In particular, there are concerns that WPT’s radiated emissions could cause harm to humans and the neighboring electronic equipment. There are many challenges that need to be overcome, but a key concern is understanding WPT’s electromagnetic compatibility (EMI: Electro-Magnetic Interference and EMF: Electro-Magnetic Field). In this paper, we show the technical issues, the evaluation method, and the development status of EMI and EMF on PHVs/EVs when using WPT. For Electromagnetic interference (EMI) performance, we investigated both an open area test site and an electromagnetic anechoic chamber as evaluation environments.

An investigation was conducted into pressure pulsation in the exhaust port, which greatly affects volumetric efficiency and engine performance. From experiments using a single blow-down generator, it was established that the amplitude of the pressure pulsation increases as the manifold branch is lengthened and that large negative pressure synchronized with the timing of valve overlap can be obtained if a proper branch length is used. The performance of a 2ℓ test engine was optimized by varying the length of both the manifold branches and front pipe forks. It was found that whereas front pipe fork length affects engine performance over only a narrow range of engine speed, optimizing manifold branch length results in a considerable improvement over a wide engine speed range. In the course of optimizing the exhaust pipe manifold length of this two-degree-of-freedom exhaust system, abnormal exhaust noises were emitted at specific engine speeds during deceleration.

In order to determine the main factors causing the mileage-related increase in formaldehyde emission from methanol-fueled vehicles, mileage was accumulated on three types of vehicle, each of which had a different air-fuel calibration system. From exhaust emission data obtained during and after the mileage accumulation, it was found that lean burn operation resulted in by far the highest formaldehyde emission increase. An investigation into the reason for the rise in engine-out formaldehyde emission revealed that deposits in the combustion chamber emanating from the lubricating oil promotes formaldehyde formation. Furthermore it was learnt that an increase in engine-out NOx emissions promotes partial oxidation of unburned methanol in the catalyst, leading to a significant increase in catalyst-out formaldehyde emission.

Small bore diesel engines often adopt a two-valve cylinder head and a non-central injector layout to expand the port flow passage area. This non-central injector layout causes asymmetrical gas flow and fuel distribution, resulting in worse heat losses and a less homogenous fuel-air mixture than an equivalent four-valve cylinder head layout with a central injector. This paper describes the improvement of piston bowl geometry to achieve a more homogeneous gas flow and fuel-air mixture. This concept reduced fuel consumption by 2.5% compared to the original piston bowl geometry, while also reducing NOx emissions by 10%.

A dynamics model considering series rigidity was constructed to examine suspension friction, which has a major effect on ride comfort on paved roads. The friction characteristics of the bushings, ball joints, and shock absorbers are expressed with series elastic elements such as arm rigidity and the spring constant of the oil seals. It was confirmed that the calculated values for the overall spring constant and damping coefficient of the suspension virtually matched values measured in a 4-post shaker test. In addition, the results of analysis using this dynamics model confirmed that the degree of friction affects both the damping coefficient and the spring constant of the suspension, especially when the series rigidity is high. Also highly rigid friction has an adverse effect on sprung motion in frequency ranges above 15 Hz. After suspension enhancements were adopted based on these findings, 4-post shaker tests confirmed that sprung motion above 2 Hz improved..

Improving vehicle fuel economy is a central part of efforts toward achieving a sustainable society. An effective way for accomplishing this aim is to enhance the engine thermal efficiency. Measures to mitigate knocking and reduce engine cooling heat loss are important aspects of enhancing the engine thermal efficiency. Cooled exhaust gas recirculation (EGR) is regarded as a key technology because it is capable of achieving both of these objectives. For this reason, it has been adopted in a wide range of both hybrid and conventional vehicles in recent years. Toyota has been introducing these technologies as ESTEC (Economy with Superior Thermal Efficient Combustion). Improving cycle-to-cycle variations in combustion, in addition to fast combustion is essential for achieving high engine thermal efficiency.

Injuries in car to pedestrian collisions are affected by various factors such as the vehicle body type, pedestrian body size and impact location as well as the collision speed. This study aimed to investigate the influence of such factors taking a Finite Element (FE) approach. A total of 72 collision cases were simulated using three different vehicle FE models (Sedan, SUV, Mini-Van), three different pedestrian FE models (AM50, AF05, AM95), assuming two different impact locations (center and the corner of the bumper) and at four different collision speeds (20, 30, 40 and 50 km/h). The impact kinematics and the responses of the pedestrian model were validated against those in the literature prior to the simulations. The relationship between the collision speed and the predicted occurrence of head and chest injuries was examined for each case, analyzing the impact kinematics of the pedestrian against the vehicle body and resultant loading to the head and the chest.