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In this study, a new practical design method (tool) for engine sound quality in a car interior is proposed. The tool can automatically create the target interior sound using the psychoacoustic index ‘powerfulness’ based on subjective tests. Moreover, it can calculate the intake noise characteristic to create the target interior sound and select the suitable intake specification from the prepared database. By using this method sound engineering can be easily and effectively carried out without manufacturing an experimental car.

Brake squeal is a phenomenon of self-induced vibration of the brake components during braking. There are many kinds of brake squeal cases whose mechanisms require acting on a various number of potential root causes. Brake squeal phenomena can be generally separated into 2 main mode types related to the direction of disc vibration involved: in-plane mode and out-of-plane mode. For out-of-plane mode, a number of existing countermeasures can be potentially applied after characterization of the squeal occurrence condition by direct experiment or simulation analysis[1,2,3,4]. However, as there are many possible mechanisms and root causes for the in-plane modes[5,6,7,8,9,10,11,12,13], it is generally necessary to perform a detailed analysis of the vibration mechanism before implementing a countermeasure.

The research described in this paper focused on improving occupant ride comfort and road holding by suppressing sprung and unsprung vibration using a semi-active suspension system. It has been reported that occupants tend to perceive vertical vibrations in a frequency range between 4 and 8 Hz as uncomfortable (described below as the “mid-frequency range”). Previous research into semi-active suspension system has focused on reducing vibration in this mid-frequency range, as well as close to the sprung resonance frequency of between 1 and 2 Hz. Skyhook damper (SH) control is a typical ride comfort control used to damp vibration close to the sprung resonance frequency. However, since SH control is not capable of damping vibration in the mid-frequency range, the shock absorbers are configured with a lower damping factor. This helps to achieve a good balance between reducing vibration close to the sprung mass resonance and in the mid-frequency range.

Whinning gear noise(final gear noise), one of the causes for automobile interior noise is due to the exciting force of final gear kit and as a general countermeasure for this problem, a reduction of resonance level in transfer system and better meshing of gears have been utilized. However,vibration characteristics of final gear unit have not been considered much in this case. Authors have executed impacting test on final gear unit and confirmed its vibration characteristics. Based on this fact,vibration model consisting of bearings and gears spring system was constructed to evaluate vibration characteristics of final gear unit along with the results obtained from final gear unit of front engine,rear drive passenger car.

The dissolution and exfoliation of chromium plating specific to Russia was studied. Investigation and analysis of organic compounds in Russian soil revealed contents of highly concentrated fulvic acid. Additionally, it was found that fulvic acid, together with CaCl2 (a deicing agent), causes chromium plating corrosion. The fulvic acid generates a compound that prevents reformation of a passivation film and deteriorates the sacrificial corrosion effectiveness of nickel.

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.

Teammate Advanced Drive is a driving support system with state-of-the-art automated driving technology that has been developed for customers’ safe and secure driving on highways based on the Toyota’s Mobility Teammate Concept. This SAE Level 2 (L2) system assists overtaking, lane changes, and branching to the destination, in addition to providing hands-free lane centering and car following. The automated driving technology includes self-localization onto a High Definition Map, multi-modal sensing to cover 360 degrees of the surrounding environment using fusion of LiDARs, cameras, and radars, and a redundant architecture to realize fail-safe operation when a malfunction or system limitation occurs. High-performance computing is provided to implement deep learning for predicting and responding to various situations that may be encountered while driving.

This paper describes a design tool and a software platform for FlexRay systems that are investigated in Nagoya University and are proposed to JasPar. The design tool reads the specification of a system as a task graph that consists of a set of tasks and messages among them. The design tool, then, allocates the tasks to ECUs and schedules the messages on a FlexRay network. The software platform consists of a middleware called time-trigger module (TTM) which dispatches time-triggered tasks, a communication middleware for a time-triggered network (TT-COM), a network management middleware for FlexRay (FlexRay-NM), and a device driver for FlexRay controller.

This paper covers the application of hybrid vibro-acoustic simulation methods to shorten the design cycle of power-plant components. A comparison is made between Frequency Response Function based and Modal based algorithms for the generation of a predictive powerplant assembly model. The effectiveness of design modifications is evaluated by loading the original and modified predictive models with experimentally identified excitation forces. The procedure is validated by correlation with experimental data.

The whirl noise on turbochargers is generated by the self-induced vibration of the oil film in the bearing system. The noise is characterized by its frequency behavior that doesn't increase proportionately to the turbo shaft speed. It tends to be felt annoying. In this paper, to improve the whirl vibration, a statistical analysis approach was applied to the bearing specifications. The results from experiments showed that the bearing clearances played an important role in the reduction of the whirl vibration. To further investigate into this phenomenon, the shaft oscillation behavior was measured. And a vibration simulation program for the turbocharger bearing system was also developed.

To reduce cabin noise and vehicle weight (for lower fuel consumption), a lightweight soundproofing cover was developed as a countermeasure to sources of noise, using the Biot theory (vibration propagation theory in poroelastic materials). This report also presents the results of its application to a metal belt-type continuously variable transmission (CVT) used in Toyota Motor Corporation’s 2.0L vehicles.

Breath alcohol interlock systems are used in Europe and the U.S. for drunk driving offenders, and a certain effect has been revealed in the prevention of drunk driving. Nevertheless, problems remain to be solved with commercialized detectors, i.e., a person taking the breath alcohol test must strongly expire to the alcohol detector through a mouthpiece for every test, more over the determination of the breath alcohol concentration requires more than 5 seconds. The goal of this research is to develop a device that functions suitable and unobtrusive enough as the interlock system. For this purpose, a new alcohol detector, which does not require a long and hard blowing to the detector through a mouthpiece, has been investigated. In this paper, as a tool available on board, a contact free alcohol detector for the prevention of drunk driving has been developed.

Low frequency interior wind noise is typically dominated by underfloor flow noise. The source mechanisms are fluctuating surface pressure loading from both flow turbulence and acoustic field levels developed in the semi-reverberant cavity between floor and road. Previous studies have used computation fluid dynamics (CFD) to estimate the aero-acoustic loading applied to a vibro-acoustic model, which is then used to predict the transmitted interior wind noise. This paper reports a new perspective in two respects. First it uses novel surface pressure microphone arrays to directly measure the underfloor aero-acoustic loading in the wind tunnel. Second, it considers two different underfloor aerodynamic configurations - with and without lightweight aero cover panels, which are installed primarily to reduce aerodynamic drag.

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.

The multilayer vehicle trim is well known for its effective influence upon noise and vibration characteristics not only in the high-frequency range but also in the low and mid-frequency ranges. FEM technologies which represent the accurate stiffness, mass and damping of trim parts such as the dash silencer and the floor carpet are essential in order to extend current body FEM capability to the road noise and the engine noise issues generated in the mid-frequency range. Conventional modeling methodologies such as local impedance and/or spring-mass modeling that express absorption and insulation properties of acoustic trim contain limitations in the mid-frequency range. There are few reliable FEM technologies to create practical vehicle models that represent the precise characteristics of the trim. In this paper, poroelastic modeling of acoustic multilayer trim was established by employing Biot theory.

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.

There are various standards to evaluate the quality of software. Tools to quantatively evaluate the quality of software have become available in recent year. Although these tools are effective, warning reports can become extensive, when the volume of software becomes large. And, the manpower to confirm the report also becomes large. Knowledge and experience are to analyze the warning report. Consequently, an oversight, a misapprehension, etc. may arise. To solve this problem, we are examining system to automate this work.

A method for predicting body deformation during operation, which cannot be measured by conventional methods, has been developed. The method creates a body model based on the characteristics extracted by modal analysis of the results of a vibration testing of an actual vehicle. The model is combined with a suspension model, using multibody dynamics software, and body deformation calculations are performed. In this paper, the influence of body deformation on vehicle controllability and stability is studied and the usefulness of the method is verified.

The world's first mass production gasoline hybrid passenger car, the “Prius”, was introduced into the Japanese market in 1997. By the time it was introduced into the American and European markets in Mid-2000, its fuel consumption and exhaust emissions had been further improved while achieving superior NV performance compared with conventional vehicles with 1.5-liter engines even in these competitive markets. This paper describes NV reduction technology for problems peculiar to the hybrid vehicle such as engine start/stop vibration, drone noise and vibration at low engine speed and motor/generator noise and vibration. It also compares the overall NV performance of the hybrid vehicle with conventional gasoline engine vehicles.

The new gasoline hybrid car, “the Prius”, has achieved both two-liter class power performance and world top-class gas mileage with the new Toyota Hybrid System “THS II”. Compared with the previous THS, the electric motor drive power of the THS II has been boosted by 50% and the weight of this system has been reduced by 20%. This paper describes the NV problems caused by the improvements to the hybrid system, and the countermeasures for them. It also describes the technologies for reduction of engine start vibration. Finally an evaluation method and countermeasures against interior engine noise are described.