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Toyota's Comprehensive Environmental Technology: Providing Choices for Sustainable Mobility

2011-11-04
In the pursuit of a sustainable transportation systems, Toyota is considering a comprehensive approach pursuing multiple advanced technologies to address three primary issues: GHG, Petroleum Use, and Air Quality. Vehicles must be ready for and affordable to the mass market to provide the customer choices to meet their transportation needs whether it is EV's, Hybrids, Plug-In Hybrids or Fuel Cell Hydrogen Hybrids. Our studies have shown that EVs have the potential to provide significant improvements in energy utilization especially combined with other advanced technologies. Toyota believes that a combination of these technolgies will provide complementary solution that enables a sustainable transportation system. Presenter Takehito Yokoo, Toyota Motor Corporation
Technical Paper

Development of an Engine Torque Estimation Model: Integration of Physical and Statistical Combustion Model

2007-04-16
2007-01-1302
Recent engine systems have become complex due to the requirements of fuel efficiency, exhaust gas emission control and good drivability. To decrease engine development period, model-based development has been adopted [1]. For torque-based vehicle control, engine torque estimation models are necessary. Simple mean-value torque models are available but these models require large amount of test data for development and validation. In addition, they cannot estimate transient torque precisely. On the other hand, complex physical models require considerable time for modeling and simulation. In order to decrease modeling time and retain model accuracy, the Wiebe function is utilized to calculate the heat release rate.
Technical Paper

A Molecular Dynamics Analysis of the Traction Fluids

2007-04-16
2007-01-1016
Non-equilibrium all-atom MD simulations are used to study the traction properties of hydrocarbon fluids. A fluid layer is confined between two solid Fe plates under the constant normal force of 1.0 GPa. Traction simulations are performed by applying a relative sliding motion to the Fe plates. Shear behaviors of nine hydrocarbon fluids are simulated on a sufficiently large film thickness of 6.7 nm, and succeeded in reproducing the order of the experimental traction coefficients. The dynamic mechanism of the momentum transfer on layers of fluid molecules are analyzed focusing on the intermolecular interactions (density profile, orientation factor, pair-correlation function) and intramolecular interactions (intramolecular interaction energy, conformation change of alicyclic ring). In contrast to the case of n-hexane, which shows low traction due to a fragile chain-like interaction, other mechanisms are obtained in the high traction molecules of cyclohexane, dicyclohexyl and santotrac 50.
Technical Paper

Improvements in Low Temperature Diesel Combustion with Blending ETBE to Diesel Fuel

2007-07-23
2007-01-1866
The effects of blending ETBE to diesel fuel on the characteristics of low temperature diesel combustion and exhaust emissions were investigated in a naturally-aspirated DI diesel engine with large rates of cooled EGR. Low temperature smokeless diesel combustion in a wide EGR range was established with ETBE blended diesel fuel as mixture homogeneity is promoted with increased premixed duration due to decreases in ignitability as well as with improvement in fuel vaporization due to the lower boiling point of ETBE. Increasing the ETBE content in the fuel helps to suppress smoke emissions and maintain efficient smokeless operation when increasing EGR, however a too high ETBE content causes misfiring at larger rates of EGR. While the NOx emissions increase with increases in ETBE content at high intake oxygen concentrations, NOx almost completely disappears when reducing the intake oxygen content below 14 % with cooled EGR.
Technical Paper

Improvement of DI Diesel Engine System by Utilizing GTL Fuels Characteristics

2009-06-15
2009-01-1933
Gas To Liquid (GTL) fuels synthesized from natural gas are known as clean fuels. Therefore, GTL fuels have been expected to be a promising option that can reduce the NOx and PM emissions from diesel engines and contribute to the energy security. In this study, in order to clarify the emission reduction potentials, the improvement of DI diesel engine and aftertreatment systems were investigated by utilizing GTL fuels characteristics. To achieve a further reduction of both NOx and PM emissions, the combustion chamber, injection pattern and EGR calibration were modified. From the results of tests, the engine out NOx emissions were reduced to the Euro 6 regulation level and in parallel the expected deteriorations of HC emission and fuel consumption were suppressed because of the characteristics of high cetane number and zero poly-aromatics hydrocarbons. Additionally, an aftertreatment system was optimized to GTL fuel in order to improve NOx conversion efficiency.
Technical Paper

Development of Double-Layered Three-Way Catalysts

2009-04-20
2009-01-1081
It is critical to develop high performance three-way catalysts to meet increasing regulations around the world. It was found that a double-layered catalyst loaded with Pt and Rh suppresses Pt-Rh alloying, thereby improving catalytic performance. A double-layered catalyst has the effect of decreasing OSC performance, but this has been overcome by a newly developed Rh support and suppressed Pt grain growth. The developed catalyst is capable of lowering the amount of PGM required by approximately 40%.
Technical Paper

Study of Large OSC Materials (Ln2O2SO4) on the Basis of Sulfur Redox Reaction

2009-04-20
2009-01-1071
Three-way catalyst shows high performance under stoichiometric atmosphere. The CeO2-ZrO2 based materials (CZ) are added as a buffer of O2 concentration. To improve the catalyst performance the larger O2 storage capacity (OSC) are needed. Theoretically, the sulfur oxidation-reduction reaction moves oxygen 8 times larger than cerium. We focused on this phenomenon and synthesized Ln2O2SO4 as a new OSC material. The experimental result under model gas shows that the OSC of Ln2O2SO4 is 5 times lager than CZ.
Technical Paper

Development of Low Sulfated Ash and Fuel Economy Diesel Engine Oil

2009-06-15
2009-01-1845
A low sulfated ash (S.Ash) DL-1/C2 0W-30 diesel engine oil with improved fuel economy has been developed to meet the PM targets outlined in the Euro 5 emissions standards and to help achieve the voluntary European CO2 target of 140 g/km. The newly developed engine oil is an effective solution to the trilemma (triple probrem) of reliability (high detergency and high anti wear), low S.Ash, and fuel economy, achieving a fuel economy improvement of 2% and reducing CO2 emissions by 3 g/km.
Technical Paper

Development of Fuel Cell Hybrid Vehicle by Toyota -Durability-

2009-04-20
2009-01-1002
Various issues must be resolved before sustainable mobility can be achieved, the most important of which are reacting to energy supply and demand, and lowering CO2 emissions. At present, the fact that the vast majority of vehicles run on conventional oil is regarded as a problem for which Toyota Motor Corporation (TMC) is developing various technological solutions. Fuel cell (FC) technology is one of the most promising of these solutions. A fuel cell is an extremely clean device that uses hydrogen and oxygen to generate power without emitting substances like CO2, NOx, or PM during operation. Its energy efficiency is high and it is widely expected to form the basis of the next generation of powertrains. Since 1992, TMC has been working to develop the main components of fuel cell vehicles, including the fuel cell itself, and the high pressure hydrogen tank and hybrid systems.
Technical Paper

Study on the Potential Benefits of Plug-in Hybrid Systems

2008-04-14
2008-01-0456
There is ever increasing interest in the issues of fossil fuel depletion, global warming, due to increased atmospheric CO2, and air pollution, all of which are due in some extent to transportation, including automobiles. Hybrid Vehicles (HVs), whose performance and usage are equivalent to existing conventional vehicles, attract lots of attention and have started to come into wider use. Meanwhile, EVs have been considered by many as the best solution for the issues mentioned above. But the technical difficulty of battery energy density is an obstruction to successful implementation. Currently the Plug-in HV (PHEV), which combines the advantages of HV and EV, is being considered as one promising solution. PHEVs can be categorized into two types, according to operating modes. The first uses battery stored energy initially, only stating the internal combustion engine when the battery is depleted. This we call the All Electric Range (AER) system.
Technical Paper

Newly Developed Toyota Plug-in Hybrid System and its Vehicle Performance under Real Life Operation

2011-06-09
2011-37-0033
Toyota has been introducing several hybrid vehicles (HV) since 1997 as a countermeasure to the concerns raised by automobile, like CO2 reduction, energy security, and pollutant emission reduction in urban areas. Plug in hybrid Vehicle (PHV) uses electric energy from grid rather than fuel for most short trips and therefore presents a next step forward towards an even more effective solution for these concerns. For longer trips, the PHV works as a conventional hybrid vehicle, providing all the benefits of Toyota full hybrid technology, such as low fuel consumption, user-friendliness and long cruising range. This paper describes a newly developed plug-in hybrid system and its vehicle performance. This system uses a Li-ion battery with high energy density and has an EV-range within usual trip length without sacrificing cabin space.
Technical Paper

CAE Methodology for Optimizing NVH, Functional Reliability, and Mass Reduction at Engine Concept Design Phase

2011-05-17
2011-01-1511
Due to the global economic downturn and higher environmental awareness, the social demands for low cost and fuel efficient vehicles are increasing. At the same time the engine power is increasing and customer expectations of reliability and NVH levels are increasing. To meet all the requirements, engineers are challenged to design light weight parts with higher performance. However, unconsidered mass reduction carries a risk of compromised NVH, Functional Reliability, and other functional demands. In order to resolve this contradiction, it is important to establish a basic structure with minimum necessary mass at the concept design phase, when there are still many degrees of freedom in the design space. Hence, a multi-objective optimization CAE methodology applicable for designing the basic structure of the Engine system was developed and is detailed below.
Technical Paper

Development of Low Pressure Loop EGR System for Diesel Engines

2011-04-12
2011-01-1413
Low pressure loop (LPL) EGR systems are effective means of simultaneously reducing the NOx emissions and fuel consumption of diesel engines. Further lower emission levels can be achieved by adopting a system that combines LPL EGR with a NOx storage and reduction (NSR) catalyst. However, this combined system has to overcome the issue of combustion fluctuations resulting from changes in the air-fuel ratio due to EGR gas recirculation from either NOx reduction control or diesel particulate filter (DPF) regeneration. The aim of this research was to reduce combustion fluctuations by developing LPL EGR control logic. In order to control the combustion fluctuations caused by LPL EGR, it is necessary to estimate the recirculation time. First, recirculation delay was investigated. It was found that recirculation delay becomes longer when the LPL EGR flow rate or engine speed is low.
Technical Paper

Feasibility Study of Exhaust Emissions in a Natural Gas Diesel Dual Fuel (DDF) Engine

2012-09-10
2012-01-1649
The Diesel Dual Fuel (DDF) vehicle is one of the technologies to convert diesel vehicles for natural gas usage. The purpose of this research was to study the possibility of a DDF vehicle to meet emission standards for diesel vehicles. This research was done for small passenger vehicles and commercial vehicles. The exhaust emissions compliance of such vehicles in a New European Driving Cycle (NEDC) mode which was composed of Urban Driving Cycles (UDC) and an Extra Urban Driving Cycle (EUDC) was evaluated. (see APPENDIXFigure A1) In this study, the passenger vehicle engine, compliant with the EURO4 standard, was converted to a DDF engine. Engine bench tests under steady state conditions showed similar result to previous papers. Total hydrocarbon (HC) emission was extremely high, compared to diesel engine. The NEDC mode emissions of the DDF vehicle were estimated based on these engine bench test results.
Technical Paper

Development of High-Strength Aluminum Piston Material

2010-04-12
2010-01-0220
Mass reduction of parts is growing in importance as a means for reducing CO2 emissions from vehicles.The aim of the present research was to contribute to further mass reduction of pistons by developing a new aluminum casting material with highest level of fatigue strength. This goal was achieved using a development concept of creating a homogeneous structure in which Ti was added to create a fine structure and appropriate quantities of Fe and Mn were added to form a compound that is stable at high temperatures. Stand-alone tests of prototype pistons fabricated using the developed material show that the material is 14% stronger than the conventional material, thereby enabling increases in power and mass reduction.
Technical Paper

Development of Two Layer Flow HVAC Unit

1999-03-01
1999-01-1199
In vehicles using a typical heating, ventilating, and air conditioning (HVAC) unit, ventilation loss through the cabin accounts for more than 60% of the heating load. This fact has increasingly important because of the low heat source characteristics of today's increasingly efficient engines. In response to this trend, a new type of air conditioning system, a “Two layer flow HVAC unit”, has been developed. This unit sends low humidity fresh intake air to the window neighborhood in order to promote good demist performance and warm recirculated air to the occupant foot area for increased efficiency. With this system, it is possible to reduce the ventilation loss by half and to raise the cabin temperature by 5°C.
Technical Paper

Indoor Pass-by Noise Evaluation System Capable of Reproducing ISO Actual Road Surface Tire Noise

2016-04-05
2016-01-0479
Generally, pass-by noise levels measured outdoors vary according to the influence of weather conditions, background noise and the driver’s skill. Manufactures, therefore, are trying to reproduce proving ground driving conditions on a chassis dynamometer. The tire noise that occurs on actual road surfaces, however, is difficult to reproduce in indoor tests. In 2016, new pass-by noise regulations (UN R51-03) will take effect in Europe, Japan and other countries. Furthermore, stricter regulations (2dB) will take effect in 2020. In addition to the acceleration runs required under current regulations, UN R51-03 will require constant speed runs. Therefore, an efficient measurement methods are necessary for vehicle development. To solve the above mentioned issues, an indoor evaluation system capable of reproducing the tire noise that occurs on road surfaces has been developed.
Technical Paper

Development of Low Pressure and High Performance GPF Catalyst

2018-04-03
2018-01-1261
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.
Technical Paper

Research on the Measures for Improving Cycle-to-Cycle Variations under High Tumble Combustion

2016-04-05
2016-01-0694
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.
Technical Paper

Development of High Tumble Intake-Port for High Thermal Efficiency Engines

2016-04-05
2016-01-0692
Improving vehicle fuel economy is a central part of efforts toward achieving a sustainable society. An effective way of accomplishing this is to enhance the engine thermal efficiency. Mitigating knock and reducing engine heat loss are important aspects of enhancing the 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 vehicles and conventional vehicles in recent years. In EGR equipped engines, fast combustion is regarded as one of the most important technologies, since it realizes higher EGR ratio. To create fast combustion, generation of strong in-cylinder turbulence is necessary. Strong in-cylinder turbulence is achieved through swirl, squish, and tumble flows. Specifically high tumble flow has been adopted on a number of new engines because of the intense effect of promoting in-cylinder turbulence.
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