Search Results

Exhaust and evaporative emissions systems have been developed to match the characteristics and usage of the Toyota THS II plug-in hybrid electric vehicle (PHEV). Based on the commercially available Prius, the Toyota PHEV features an additional external charging function, which allows it to be driven as an electric vehicle (EV) in urban areas, and as an hybrid electric vehicle (HEV) in high-speed/high-load and long-distance driving situations. To reduce exhaust emissions, the conventional catalyst warm up control has been enhanced to achieve emissions performance that satisfies California's Super Ultra Low Emissions Vehicle (SULEV) standards in every state of battery charge. In addition, a heat insulating fuel vapor containment system (FVS) has been developed using a plastic fuel tank based on the assumption that such a system can reduce the diffusion of vapor inside the fuel tank and the release of fuel vapor in to the atmosphere to the maximum possible extent.

The original Toyota Hybrid System (THS) was installed in the Prius and was introduced in 1997 as the world's first mass-produced hybrid passenger car. Since then, THS has been continuously improved. In 2003 THS-II (marketed as Hybrid Synergy Drive [HSD]), was installed in a new larger Prius. In 2006 HSD was installed in a Rear Wheel Drive Vehicle: the LEXUS GS450h. This system achieved both 4.5-liter class power performance and compact class fuel economy with outstanding emissions performance. In 2007, this system is expanded to a mechanical all-wheel-drive(AWD) in the LEXUS LS600hL(with new V8 engine). This paper will explain this hybrid system which achieved both V12 class power performance and mid-size class fuel economy, while meeting the most stringent emission standard SULEV as a full-size vehicle.

Toyota has been evolving a hybrid system since introducing the first mass-production hybrid vehicle in 1997 in response to the increasing automotive-related issues of CO2 emissions, energy security, and urban air pollution. This paper describes a newly developed hybrid system design and its performance. This system was developed with the main purpose to improve fuel consumption, especially for better real world fuel consumption; and to enhance its compatibility with multiple vehicle adoption by downsizing and reducing the weight of its components. At the same time, the hybrid system achieved improved power performance while satisfying stringent emission regulations in the world.

Toyota Hybrid System (THS), the powertrain that combines a gasoline engine and an electric motor was first introduced in December 1997. It became the first mass-produced hybrid passenger vehicle in the world, gaining a reputation as a highly innovative vehicle, and its cumulative worldwide sales have exceeded 120,000 units. In 2003, THS had a further evolution. The “new-generation Toyota Hybrid System (THS II)” would be introduced on the new Prius. This report shall explain “THS II”, which achieved drastic improvements in power performance and fuel economy, while securing the most stringent emission standard Advanced Technology Partial Zero Emission Vehicle (ATPZEV).

In order to correspond to the exhaust emissions regulations that become severe every year, more advanced engine control becomes necessary. Engine engineers are concerned about the Hydrocarbons (HCs) that flow through the air-intake ports and that are difficult to precisely control. The main sources of the HCs are, the canister purge, PCV, back-flow gas through the intake valves, and Air / Fuel ratio (A/F) may be aggravated when they flow into the combustion chambers. The influences HCs give on the A/F may also grow even greater, which is due to the increasingly stringent EVAP emission regulations, by more effective ventilation in the crankcase, and also by the growth of the VVT-operated angle and timing, respectively. In order to control the A/F more correctly, it is important to estimate the amount of HCs that are difficult to manage, and seek for suitable controls over fuel injection and so on.

Toyota Motor Corporation developed the Fuel Cell Hybrid Vehicle (FCHV). The FCHV-4 is an evolution of the conventional fuel cell vehicle that has made immense improvements in efficiency. Both a fuel cell and a secondary battery are used as sources of energy for the hybrid system. By using these energy sources proportionally, the system can be kept at or near its optimum state. The FCHV-4's system is designed to improve the efficiency and aims for high responsiveness when the vehicle is in a transitional state. In the same way as most electric vehicles, and as in the gasoline powered hybrid “Prius”, the energy the traction motor creates during breaking can be used to regenerate the secondary. The fuel cell and traction motor inverter are connected directly, with the secondary battery connected through the DC/DC converter to the fuel cell in parallel.

Development of a new battery system for Toyota Estima Hybrid, the world's first minivan hybrid vehicle, has been completed. The battery pack that consists of 30 nickel metal hydride battery modules is compactly arranged under the 3rd seat in the cabin along with components such as the battery cooling blower and the ducts. This arrangement was designed in consideration of user's vehicle use, passengers' comfort and efficient battery-cooling performance.

In order to adapt to energy security and the changes of global-scale environment, further improvement of fuel economy and adaptation to each country’s severer exhaust gas emission regulation are required in an automotive engine. To achieve higher power performance with lower fuel consumption, the engine’s basic internal design such as an engine block and cylinder head were changed and the combustion speed was dramatically increased. Consequently, stroke-bore ratio and valve layout were optimized. Also, both flow coefficient and intake tumble ratio port were improved by adopting a laser cladded valve seat. In addition, several new technologies were adopted. The Atkinson cycle using a new Electrical VVT (Variable Valve Timing) and new combustion technology adopting new multi-hole type Direct fuel Injector (DI) improved engine power and fuel economy and reduced exhaust emissions.

Achieving the speed and performance of a true supercar was merely the starting point of this development. In addition, the development also focused on achieving emotive performance attributes to enhance driver appeal. For this the engine was developed to assist a vehicle handling provides unsurpassed response, the creating a feeling of infinite acceleration potential, response is instantaneous and based on close understanding of driver's reactions and Awe inspiring sound is providing. It meets the latest emission standard Euro V and achieves good fuel consumption with a wide range stoechiometric air fuel ratio, till speeds up to 240km/h.

After the Great East Japan Earthquake on March 11, 2011, Toyota Motor Corporation received considerable public response regarding the role of vehicles in emergencies from a large number of customers. These included comments about the usefulness of the electricity supply system in the Estima Hybrid during the long power outages caused by the earthquake. In response, Toyota decided to install this system in its other hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs). This system is capable of supplying power up to 1,500 watts, which means that it can be used to operate virtually every household electrical device. Since the engine starts automatically when the main battery capacity is depleted, a single vehicle can supply the daily power needs of a normal house in Japan for about four days, providing that the battery is fully charged and the fuel tank is full.

The original Toyota Hybrid System (THS) was installed in the Prius and was introduced in 1997 as the world's first mass-produced hybrid passenger car. THS has been continuously improved. In 2003 THS-II (marketed as Hybrid Synergy Drive [HSD]), was installed in a new larger Prius. In 2005 HSD was installed in two SUVs: the RX400h and Highlander Hybrid. This system achieved both V8 engine power performance and compact class fuel economy with outstanding emissions performance. In 2006, the HSD line-up is expanded to front-engine rear-wheel (FR) drive in the Lexus GS450h. This paper will explain this hybrid system which achieves both 4.5-liter class power performance and compact class fuel economy, while meeting the most stringent emission standard SULEV.

The 1ZZ-FE engine is a newly developed in-line 4-cylinder, 1.8-liter, DOHC 4-valve engine mounted in the new Corolla. Abounding in new technologies including the laser-clad valve seat, high-pressure die-cast aluminum cylinder block, and the small-pitch chain drive DOHC, coupled with the fundamentally reviewed basic specifications, the new engine is compact and lightweight, offering high performance and good fuel economy. Anticipating even more stringent emission regulations in the future, in addition to the revision of the engine body, the layout of the exhaust system has been improved to enhance warm-up performance of the converter.

In the field of automotive body electronic control such as control of door locks, power windows, and wipers, there is a growing need of multiplexing communication to reduce the amount of wire harnesses. To meet this need, we developed a multiplexing communication protocol particularly suited to the body electronic control. Based on the developed protocol, we designed a communication control IC and a simple driver/receiver circuit with a few discrete components. The bus access method of the communication is the CSMA/CD with nondestructive bit arbitration, and its bit rate is 5 kbps. Its transmission media is a single wire. The communication IC has a multiplexing control block and a serial I/O block for an interface with a host CPU. It was fabricated using CMOS technology and has a chip of 2.6mm x 3.0mm in size that contains about 5,000 transistors. The driver/receiver circuit consists of one transistor, one capacitor and several resistors.

A new generation 3.0 liter V6 engine, the 1MZ-FE, has been developed. Through improvement of the basic technical characteristics of each individual component, the 1MZ-FE has achieved compactness, weight reduction and good fuel economy without adding systems or components. This new engine makes use of an aluminum cylinder block, and compared with the previous V6 engine, significant weight reduction of the crankshaft, connecting rods and pistons was achieved while still maintaining a high level of rigidity. To improve fuel economy, friction loss was reduced substantially by reducing the weight of moving parts and improving the surface roughness of sliding parts. The combustion was also improved through better fuel atomization by the air-assisted fuel injector and modification of the combustion chamber shape. Through these improvements the 1MZ-FE has achieved a weight reduction of approximately 20% and far greater vehicle fuel economy than before.

Toyota Hybrid System (THS), that combines a gasoline engine and an electric motor was installed in the Prius, which was introduced in 1997 as the world's first mass-produced hybrid passenger car, and was vastly improved in 2003. The new Prius gained a status of highly innovative and practical vehicle. In 2005, combined with a V6 engine, THS had a further evolution as a Hybrid System for SUV, which was installed in the RX400h and Highlander Hybrid to be introduced into the world. This report will explain “new THS” which achieved both V8 engine power performance and compact class fuel economy, while securing the most stringent emission standard, SULEV.

Due to increasing demands for further CO2 reduction and tighter exhaust emissions regulations, automakers are increasingly downsizing turbo-charged diesel engines by raising specific power, or adopting low-pressure loop exhaust gas recirculation (LPL-EGR) systems to improve the EGR rate. However, adopting a higher boost pressure to increase the specific power, or introducing hot exhaust gas before the turbocharger compressor with the LPL-EGR system creates higher gas temperatures in the compressor, which results in soot-containing deposits derived from the engine oil in the compressor. This phenomenon causes significant deterioration of turbocharger efficiency. Therefore, countermeasures such as restricting boost pressure or limiting EGR usage in the operational map are necessary to prevent engine performance deterioration. Increasing the gas temperature in the compressor while preventing deposit formation should enable further improvements in fuel consumption and engine power.

A methanol fueled, lean burn system has been developed to improve both specific fuel consumption and NOx emissions. A 1.6L four-cylinder engine with increased compression ratio has been used to develop this system. Three major components of the Toyota Lean Combustion System (T-LCS) have been applied: (1) A helical port with a swirl control valve (2) A lean mixture sensor (3) Timed, multi-point fuel injection. A 2250 lb. Inertia Weight test vehicle has been fitted with this engine, and fuel system materials have been modified. This methanol, lean burn system has improved the fuel economy by about 12% still satisfying the 1986 emission standards of the U.S.A. and Japan. Aldehyde emissions have also been evaluated.

The 2ZZ-GE is a sporty 1.8 liter engine based on the 1ZZ-FE, which is currently being mass produced in Japan, USA, and Canada. It was designed to fit into the same engine compartment as the base 1ZZ-FE, have equivalent vehicle performance as a 2.2 liter engine, and meet TLEV emission standards. The main features of the 2ZZ-GE are the Metal Matrix Composite (MMC) reinforced all-aluminum cylinder block and the intelligent Variable Valve Timing and Lift (VVTL-i) system. These features were adopted for size and performance. Other features such as a reinforced ladder frame, and an intake manifold spacer was utilized for a sporty engine sound. The 2ZZ-GE delivers maximum power at 7600rpm and maximum torque at 6800rpm.

Historically, greenhouse gas (GHG) emissions standards for vehicles have focused on tailpipe emissions. However, sound environmental policy requires a more holistic well-to-wheels (WTW) assessment that includes both production of the fuel and its use in the vehicle. The present research explores the net change in WTW GHG emissions associated with moving from regular octane (RO) to high octane (HO) gasoline. It considers both potential increases in refinery emissions from producing HO fuel and potential reductions in vehicle emissions through the use of fuel-efficient engines optimized for such fuel. Three refinery configurations of varying complexity and reforming capacity were studied. A set of simulations covering different levels of HO gasoline production were run for each refinery configuration.

The particle number (PN) emission regulation has been implemented since 2011 in Europe. PN measurement procedure defined in ECE regulation No. 83 requires detecting only solid particles by eliminating volatile particles, the concentrations of which are highly influenced by dilution conditions, using a volatile particle remover (VPR). To measure PN concentration after the VPR, a particle number counter (PNC) which has detection threshold at a particle size of 23 nm is used, because most solid particles generated by automotive engines are considered to be larger than 23 nm. On the other hand, several studies have reported the existence of solid and volatile particles smaller than 23 nm in engine exhaust. This paper describes investigation into a measurement method for ultrafine PNCs with thresholds of below 23 nm and evaluation of the VPR performance for the particles in this size range. The detection efficiency of an ultrafine PNC was verified by following the ECE regulation procedure.