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Journal Article

Experimental Demonstration of Smart Charging and Vehicle-to-Home Technologies for Plugin Electric Vehicles Coordinated with Home Energy Management Systems for Automated Demand Response

2016-04-05
2016-01-0160
In this paper, we consider smart charging and vehicle-to-home (V2H) technologies for plugin electric vehicles coordinated with home energy management systems (HEMS) for automated demand response. In this system, plugin electric vehicles automatically react to demand response events with or without HEMS’s coordination, while vehicles are charged and discharged (i.e., V2H) in appropriate time slots by taking into account demand response events, time-ofuse rate information, and users’ vehicle usage plan. We introduce three approaches on home energy management: centralized energy control, distributed energy control, and coordinated energy control. We implemented smart charging and V2H systems by employing two sets of standardized communication protocols: one using OpenADR 2.0b, SEP 2.0, and SAE standards and the other using OpenADR 2.0b, ECHONET Lite, and ISO/IEC 15118.
Journal Article

Improvement of Ride Comfort by Unsprung Negative Skyhook Damper Control Using In-Wheel Motors

2016-04-05
2016-01-1678
Vehicles equipped with in-wheel motors (IWMs) are capable of independent control of the driving force at each wheel. These vehicles can also control the motion of the sprung mass by driving force distribution using the suspension reaction force generated by IWM drive. However, one disadvantage of IWMs is an increase in unsprung mass. This has the effect of increasing vibrations in the 4 to 8 Hz range, which is reported to be uncomfortable to vehicle occupants, thereby reducing ride comfort. This research aimed to improve ride comfort through driving force control. Skyhook damper control is a typical ride comfort control method. Although this control is generally capable of reducing vibration around the resonance frequency of the sprung mass, it also has the trade-off effect of worsening vibration in the targeted mid-frequency 4 to 8 Hz range. This research aimed to improve mid-frequency vibration by identifying the cause of this adverse effect through the equations of motion.
Journal Article

Development of Chemical Process for Recovering High-quality Rare-earth Oxides from HV Motor Magnets

2017-03-28
2017-01-1278
In the automobile industry, interest in the prevention of global warming has always been high. The development of eco cars (HV, EV etc.), aimed at reducing CO2 emissions during operation, has been progressing. In the announcement of its "Toyota Environmental Challenge 2050", Toyota declared its commitment to creating a future in which people, cars, and nature coexist in harmony. In this declaration, Toyota committed to reducing CO2 emissions not only during operation but also over the entire life cycle of vehicles, and to using resources effectively based on a 4 R’s approach (refuse, reduce, reuse, and recycle). Although eco cars decrease CO2 emissions during operation, most of them increase CO2 emissions during manufacturing. For example, the rare-earths (Nd, Dy etc.) used in the magnets of driving motors are extracted through processes that produce a significant amount of CO2 emissions.
Journal Article

Tire and Road Input Modeling for Low-Frequency Road Noise Prediction

2011-05-17
2011-01-1690
This paper presents a modeling method for prediction of low-frequency road noise in a steady-state condition where rotating tires are excited by actual road profile undulation input. The proposed finite element (FE) tire model contains not only additional geometric stiffness related to inflation pressure and axle load but also Coriolis force and centrifugal force effects caused by tire rotation for precise road noise simulation. Road inputs act on the nodes of each rib in the contact patch of the stationary tire model and move along them at the driving velocity. The nodes are enforced to displace in frequency domain based on the measured road profile. Tire model accuracy was confirmed by the spindle forces on the rotating chassis drum up to 100Hz where Coriolis force effect should be considered. Full vehicle simulation results showed good agreement with the vibration measurement of front/rear suspension at two driving velocities.
Journal Article

Verification of ASSTREET Driver-Agent Model by Collaborating with the Driving Simulator

2012-04-16
2012-01-1161
This paper proposes a novel method of verifying comprehensive driver model used for the evaluation of driving safety systems, which is achieved by coupling the traffic simulation and the driving simulator (DS). The method consists of three-step procedure. In the first step, an actual driver operates a DS vehicle in the traffic flow controlled by the traffic simulation. Then in the next step, the actual driver is replaced by a driver model and the surrounding vehicle maneuvers are replayed using the recorded data from the first step. Then, the maneuver by the driver model is compared directly with the actual driver's maneuver along the simulation time steps.
Journal Article

Benefit Estimation of a Lane Departure Warning System using ASSTREET

2012-04-16
2012-01-0289
It is known that the collisions caused by lane departure events account for range of percentages among the countries studied. To help prevent such collisions, the Lane Departure Warning (LDW) system has started to be introduced in production vehicles, but there is little research on its benefits and limitations so far. In this paper we performed an in-depth analysis of the collisions and driver-related essential variables for the lane-departure collision scenarios and demonstrated the benefit estimation process. The benefit of the LDW system is estimated by comparing lane departure events when the vehicle has no LDW, and how they change with the addition of LDW. The event without LDW was modeled in 5 phases: (1) before departure, (2) starting of the departure, (3) departed the lane, (4) at the impact with an object, and, (5) after the impact. “An extensive analysis was conducted of traffic crash data compiled by the Institute for Traffic Accident Research and Data Analysis (ITARDA).
Journal Article

Hierarchical Accumulative Validation of Executable Control Specifications

2013-04-08
2013-01-0430
The application of Model-Based Development (MBD) techniques for automotive control system and software development have become standard processes due to the potential for reduced development time and improved specification quality. In order to improve development productivity even further, it is imperative to introduce a systematic Verification and Validation (V&V) process to further minimize development time and human resources while ensuring control specification quality when developing large complex systems. Traditional methods for validating control specifications have been limited by control specification scale, structure and complexity as well as computational limitations restricting their application within a systematic model-based V&V process. In order to address these issues, Toyota developed Hierarchical Accumulative Validation (HAV) for systematically validating functionally structured executable control specifications.
Journal Article

Development of iQ with CVT for USA

2011-04-12
2011-01-1425
TOYOTA has developed the iQ with a 1.3L engine for the Scion brand in USA. Due to the importance of fun-to-drive factor for the Scion brand image, a responsive driving performance is required even with compact packaging and a small engine. In addition, because of the recent attention to global-warming and energy issues on a global scale, development of vehicles with high fuel economy is one of the most important issues for a car manufacturer. Therefore, it is necessary for a vehicle to have both high driving performance and fuel economy. TOYOTA has adopted the CVT-i as the transmission for this purpose. The following were achieved by adopting the CVT-i as the transmission for the iQ(1.3L). 1 Responsive driving performance with shift changes without a time lag. 2 Compact transmission for efficient vehicle packaging 3 Class-leading fuel economy performance. Moreover, it was developed with adjustments for the US market by improving the shift schedule for a linear acceleration feel.
Journal Article

Development of High-Performance Driving Simulator

2009-04-20
2009-01-0450
A number of active safety systems are already developed to support drivers’ decision and action to help avoid accidents, but further enhancement of those active safety systems cannot be accomplished without increasing our understanding on driver behaviors and their interaction with vehicle systems. For this reason, a state-of-art driving simulator (DS) has been developed that creates very realistic scenarios as a means of realizing these requirements. The DS consists of a simulator cabin, turntable (inside the dome), a 6-DOF hexapod system, shakers (vehicle vertical vibration actuators), and a motion system capable of moving 35 meters longitudinally and 20 meters laterally. The system is also capable of projecting images of actual city streets and highways onto a 360° spherical screen inside of the dome. As a result, the DS is able to reproduce a driving environment that is very similar to real driving.
Technical Paper

Analysis of Personal Routing Preference from Probe Data in Cloud

2020-04-14
2020-01-0740
Routing quality always dominates the top 20% of in vehicle- navigation customer complaints. In vehicle navigation routing engines do not customize results based on customer behavior. For example, some users prefer the quickest route while some prefer direct routes. This is because in vehicle navigation systems are traditionally embedded systems. Toyota announced that new model vehicles in JP, CN, US will be connected with routing function switching from the embedded device to the cloud in which there are plenty of probe data uploaded from the vehicles. Probe data makes it possible to analyze user preferences and customize routing profile for users. This paper describes a method to analyze the user preferences from the probe data uploaded to the cloud. The method includes data collection, the analysis model of route scoring and user profiling. Furthermore, the evaluation of the model will be introduced at the end of the paper.
Journal Article

Development of Engine Lubrication System with New Internal Gear Fully Variable Discharge Oil Pump

2017-10-08
2017-01-2431
Over the past decades, the automotive industry has made significant efforts to improve engine fuel economy by reducing mechanical friction. Reducing friction under cold conditions is becoming more important in hybrid vehicle (HV) and plug-in hybrid vehicle (PHV) systems due to the lower oil temperatures of these systems, which results in higher friction loss. To help resolve this issue, a new internal gear fully variable discharge oil pump (F-VDOP) was developed. This new oil pump can control the oil pressure freely over a temperature range from -10°C to hot conditions. At 20°C, this pump lowers the minimum main gallery pressure to 100 kPa, thereby achieving a friction reduction effect of 1.4 Nm. The developed oil pump achieves a pressure response time constant of 0.17 seconds when changing the oil pressure from 120 kPa to 200 kPa at a temperature of 20°C and an engine speed of 1,600 rpm.
Technical Paper

Development of a New High Orientation Paint System to Achieve Outstanding Real Metallic Designs

2020-04-14
2020-01-0899
Silver metallic colors with thin and smooth aluminum flake pigments have been introduced for luxury brand OEMs. Regarding the paint formulation for these types of colors, low non-volatile(NV) and high aluminum flake pigment contents are known as technology for high metallic appearance designs. However, there are two technical concerns. First is mottling which is caused by uneven distribution of the aluminum flake pigments in paint film and second is poor film property due to high aluminum pigment concentration in paint film. Therefore, current paint systems have limitation of paint design. As a countermeasure for those two concerns, we had investigated cellulose nanofiber (CNF) dispersion liquid as both the coating binder and rheology control agent in a new type of waterborne paint system. CNF is an effective rheology control agent because it has strong hydrogen bonds with other fiber surfaces in waterborne paint.
Technical Paper

Experimental Analysis of Acoustic Coupling Vibration of Wheel and Suspension Vibration on Tire Cavity Resonance

2007-05-15
2007-01-2345
It is difficult to improve tire cavity noise since the pressure of cavity resonance acts as a compelling force, and its low damping and high gain characteristics dominate the vibration of both the suspension and body. For this reason, the analysis described in this article aimed to clarify the design factors involved and to improve this phenomenon at the source. This was accomplished by investigating the acoustic coupling vibration mode of the wheel, which is the component that transmits the pressure of cavity resonance at first. In addition, the vibration characteristic of suspension was investigated also. A speaker-equipped sound pressure generator inside the tire and wheel assembly was developed and used to infer that wheel vibration under cavity resonance is a forced vibration mode with respect to the cavity resonance pressure distribution, not an eigenvalue mode, and this phenomenon may therefore be improved by optimizing the out-of-plane torsional stiffness of the disk.
Technical Paper

JCAPII Cross Check Tests of Fast Electrical Mobility Spectrometers for Evaluation of Accuracy

2007-10-29
2007-01-4081
Crosscheck tests of fast electrical mobility spectrometers, Differential Mobility Spectroscopy (DMS) and Engine Exhaust Particle Sizer(EEPS), were conducted to evaluate the accuracy of fine particle measurement. Two kinds of particles were used as test particles for the crosscheck test of instruments: particles emitted from diesel vehicles and diluted in a full dilution tunnel, and particles generated by CAST. In the steady state tests, it was confirmed that the average concentration of each instrument was within the range of ±2σ from the average concentration of all the same type of instruments. In the transient tests, it is verified that the instruments have almost equal sensitivity. For application of the fast electrical mobility spectrometers to evaluation of particle number and size distributions, it is essential to develop a calibration method using reference particle counters and sizers (CPC, SMPS, etc.) and maintenance methods appropriate for each model.
Technical Paper

Exhaust Emissions Simulator for Verification of Extremely Low Emission Measurement Systems

2007-04-16
2007-01-0316
With the support of Horiba and Horiba STEC, Toyota Motor Corporation has developed an exhaust emissions simulator to verify the accuracy of extremely low emissions measurement systems. It can reliably verify the accuracy (correlation) of each SULEV emission measurement system to within 5% under actual conditions. The simulator's method of simulating SULEV gasoline engine cold-start emissions is to inject bottled gases with known concentrations of each emission constituent to the base gas, which is clean exhaust gas from a SULEV vehicle with new fully warmed catalysts. First, the frequencies and dynamic ranges of the SULEV cold-start emissions were analyzed and the method of 2 injecting the bottled gases was considered based on the results of that analysis. A high level of repeatability and accuracy was attained for all injection flow ranges in the SULEV cold-start emission simulation by switching between high-response digital Mass Flow Controllers (MFCs) of different full scales.
Technical Paper

Development of Combustion Behavior Analysis Techniques in the Ultra High Engine Speed Range

2007-04-16
2007-01-0643
In order to clarify the combustion behavior in the ultra high engine speed range, a new technique has been developed. This technique is composed of ionization current detection and flame observation, and is highly heat-resistant, vibration-resistant, and has a quick response. From analyzing the flame front propagation in the high-speed research engine, it was found that the flame propagated throughout the entire cylinder over almost the same crank angle period irrespective of engine speed introduction.
Technical Paper

Development of Suspension Design Technology Applying Principal Elastic Axes

2007-04-16
2007-01-0857
Automobile manufacturers have increased the pace of vehicle development in recent years to respond to diverse market demands. Consequently, it has become crucial for manufacturers to develop new technology which enables a particular vehicle to simultaneously achieve both ride comfort and handling performance at an optimal level. This article introduces the suspension design technology applying the Principal Elastic Axes that has been developed by our company for use in its vehicles. These axes, which consist of three translational and three rotational axes, represent the set of fully decoupled stiffness axes. Applying the Principal Elastic Axes to the suspension reduces the number of design parameters, which enables suspension movements to be considered totally and simply.
Technical Paper

Design Concept and Advantages of Steer-by-Wire System

2008-04-14
2008-01-0493
Because of recent advances in steering control technology, steer-by-wire systems have continued to become more realistic. The principal issue for these steer-by-wire systems is considered to be promoting reliability through the construction of a design concept that can be utilized appropriately by drivers. This paper first describes the flow between the concept and system structure, and proposes a steer-by-wire system with a mechanical backup mechanism as one possibility. This paper also describes an investigation into its potential advantages using an experimental vehicle installed with the proposed system structure. The potential advantages of steer-by-wire are improved vehicle driving performance, vehicle maneuverability, and the feasibility of innovative packaging and design. In order to make improved maneuverability and design innovations compatible, it is critical to achieve steering characteristics that require little maneuvering angle.
Technical Paper

Development of Direct and Fast Response Gas Measurement

2008-04-14
2008-01-0758
Due to regulations for even lower levels of pollutants in exhaust gas, development of advanced combustion techniques and increasingly efficient catalysts has become more crucial than ever. One of the essential technologies to achieve this goal is an advanced measurement method, which can detect the characteristics of exhaust gas, such as temperature and chemical compositions, in real-time to clarify their reaction mechanisms. A direct and fast response (1ms) measurement technique was developed based on diode laser absorption spectroscopy and applied to practical engine exhaust measurement to prove the validity of this technology for various applications such as clarification of engine start phenomena and improvement of EGR controls.
Technical Paper

Universal Diesel Engine Simulator (UniDES): 1st Report: Phenomenological Multi-Zone PDF Model for Predicting the Transient Behavior of Diesel Engine Combustion

2008-04-14
2008-01-0843
We have developed a novel engine cycle simulation program (UniDES: universal diesel engine simulator) to reproduce the diesel combustion process over a wide range of engine operating parameters, such as the amount of injected fuel, the injection timing, and the EGR ratio. The approach described in this paper employs a zoning model, where the in-cylinder region is divided into up to five zones. We also applied a probability density function (PDF) concept to each zone to consider the effect of spatial non-homogeneities, such as local equivalence ratios and temperature, on the combustion characteristics. We linked this program to the commonly used commercial GT-Power® software (UniDES+GT). As a result, we were able to reproduce transient engine behavior very accurately.
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