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Technical Paper

A target cascading method using model based simulation in early stage of vehicle development

2019-04-02
2019-01-0836
Vehicle specifications which satisfy various constraint conditions of target performance indices are required in the early stage of vehicle development. For this decision making, model based simulation plays important role to provide candidates of feasible specifications and can be used to find optimal specifications by applying optimization method. In order to enhance the efficiency of later development processes, those optimal specifications obtained from the optimization problem are required to be not only feasible but also flexible. To guarantee these requirements, it is important for decision maker to understand feasible region space and its mechanism where satisfies every constraint based on model based simulations. The purpose of this study is not to find best solution in design space but to understand feasible design space and its mechanism.
Technical Paper

A Study of Triple Skyhook Control for Semi-Active Suspension System

2019-04-02
2019-01-0168
It is said that a vertical vibration from 4 to 8 Hz (the mid-frequency range) particularly affects ride comfort. In order to suppress the mid-frequency range vibration, a number of control methods using a semi-active suspension system have been proposed. Skyhook damper control (SH) is a well-known strategy to suppress the vibration around the sprung mass resonance frequency about 1-2 Hz (the low-frequency range). However, the mid-frequency range vibration can’t be suppressed by SH. Therefore, dampers of the semi-active suspensions adopting SH are usually set soft to balance the low- and mid-frequency vibration. However, the soft dampers increase unsprung vibration opposite ride comfort. H-infinity and gain-scheduled approaches also have been proposed to achieve these multiple objectives. However, those controls have many tuning parameters and require information of unsprung vibration from sensors or accurate estimations.
Technical Paper

Development of Strength Distributed Hot Stamp Parts

2019-04-02
2019-01-0522
Structural parts, such as the center pillar, are a multiple structure, consisted by layers of the high-strength panels and the high-toughness panels, to control the deformation mode during a crash. If we are able to make this multi-layered structure into one panel, which has different hardness within it, we will be able to make a lightweight panel. In this study, we have developed the method to fabricate a ‘lightweight center pillar’ with the following processes. First, the whole surface of the panel is hardened by quenching in the hot stamp process. Next, certain areas of the panel are softened by the partial tempering. We have found that the temperature zone for softening is between A1 and A3 transformation temperature, and it is easy to perform a rapid and accurate tempering by utilizing the property of Induction Heating around the Curie temperature between A1 and A3 transformation temperature.
Technical Paper

Fatigue Life Prediction Method for Self Piercing Rivets Considering Crack Propagation

2019-04-02
2019-01-0531
This paper describes the numerical prediction method for fatigue strength of Self Piercing Rivets (SPRs) using fracture mechanics. Recently, high strength steels and non-ferrous metals are adopted to the light weight automotive body. Many kinds of joining are proposed for the multi material bodies. It is important to predict fatigue lives of these joints using the numerical simulation. However, the fatigue strength of joints is related to sheet thickness, base materials, and loading conditions. Therefore, a large number of coupon tests are necessary to determine the S-N curve for the fatigue life prediction of joints in the automotive body. To reduce the amount of coupon tests, the numerical simulation will be efficient for obtaining the S-N curve of joints instead of coupon tests. The fatigue fracture process consists of two stages, the small crack initiation and the crack growth. There are many studies about the crack growth estimation method using stress intensity factor.
Technical Paper

Development of TLP-AI Technology to realize high temperature operation of power module

2019-04-02
2019-01-0607
SiC power devices are promising components for the power module assembled in the automobile power control unit due to their low-power loss operation. Also they have high thermostable characteristics which are expected to tolerate high temperature operation, widening the range that the conventional Si device has limited. While, the packaging technology is also needed to improve the thermo-stability to derive the full potential of SiC power device, especially the device bonding which is directly related to the device thermally and physically. TLP bonding is one of the promising technologies for the high temperature operation because its bonding layer has high melting point. But there is a problem that characteristic of TLP bonding layer causes the damage to the power device.
Technical Paper

Research of Knocking Deterioration due to Accumulated Carbon Deposits on Piston Surfaces

2019-04-02
2019-01-1141
In recent years, fuel economy regulation is expanding to reduce CO2 emission and energy saving in world wide. To achieve the regulation, automaker efforts to develop electrification technology and improve engine thermal efficiency with high compression ratio. On the other hand, variety of fuels such as a reformed gasoline and bio fuel share is growing rapidly to utilize of fossil fuel by legal arrangements. With the spread of reformed gasoline, there are some risk of increased carbon deposit and accumulated on piston surface, due to heavy aromatic and olefin in the fuel. In combustion point of view, knocking should be deteriorated by synergy effect both accumulated carbon deposit and said high compression ratio. Furthermore, knocking deterioration do not occur in regularly, especially they occur in low-middle engine load. However, this mechanism is not clear.
Technical Paper

Using Chemical Kinetics to Understand Effects of Fuel Type and Compression Ratio on Knock-Mitigation Effectiveness of Various EGR Constituents

2019-04-02
2019-01-1140
Exhaust gas recirculation (EGR) can be used to mitigate knock in SI engines. However, experiments have shown that the effectiveness of various EGR constituents to suppress knock varies with fuel type and compression ratio (CR). To understand some of the underlying mechanisms by which fuel composition, octane sensitivity (S), and CR affect the knock-mitigation effectiveness of EGR constituents, the current paper presents results from a chemical-kinetics modeling study. The numerical study was conducted with CHEMKIN, imposing experimentally acquired pressure traces on a closed reactor model. Simulated conditions include combinations of three RON-98 (Research Octane Number) fuels with two octane sensitivities and distinctive compositions, three EGR diluents, and two CRs. The experimental results point to the important role of thermal stratification in the end-gas to smooth peak heat-release rate (HRR) and prevent acoustic noise.
Technical Paper

Effect of High RON Fuels on Engine Thermal Efficiency and Greenhouse Gas Emissions

2019-04-02
2019-01-0629
Increasing fuel octane is a well-known enabler for increasing spark-ignited engine efficiency. This research explores the impact of such a strategy on ‘well-to-wheel’ greenhouse gas emissions by considering 1) increases in emissions from producing higher octane fuels in the refinery, and 2) reductions in vehicle emissions through use of fuel-efficient engines optimized for such higher octane fuels. It also examines the impact of increases in fuel cost when refineries shift fuel production to higher octane. Three refinery configurations with different capacities to produce higher octane fuels were studied by simulating operations at three levels of high-octane gasoline production, as a function of the octane value for the high-octane grade. Two spark-ignited engine designs were considered, with different potential to take advantage of higher octane fuel to increase efficiency.
Technical Paper

Thermal Management of a Hybrid Vehicle Using a Heat Pump

2019-04-02
2019-01-0502
This paper presents the thermal management of a hybrid vehicle (HV) by using a heat pump system in cold weather. The advantage of an HV is a high efficiency of the vehicle system since an electric motor and an engine are coupled and optimally controlled. However, in the conventional HV, we see the fuel economy degradation in cold weather because delivering heat to the passenger cabin by using an engine results in a low efficiency of the vehicle system. To improve the fuel economy degradation, in this study, a heat pump is used and combined with an engine for the thermal management. The heat pump with an electrically driven compressor pumps heat from ambient into a water-cooled condenser. The heat which is 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 the emission and the cabin needs heat for thermal comfort.
Technical Paper

The Effect of Gasoline Metallic Additives on Low Speed Pre-Ignition

2018-04-03
2018-01-0936
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.
Technical Paper

Development of Three-Way Catalysts Enhanced NOx Purifying Activity

2018-04-03
2018-01-0942
Growing concerns about the depletion of raw materials as vehicle ownership continues to increase is prompting automakers to look for ways of decreasing the use of platinum-group metals (PGMs) in the exhaust systems. This research has developed a new catalyst with strong robustness against fluctuations in the exhaust gas and excellent nitrogen oxide (NOx) conversion performance. One of the key technologies is a new OSC material that has low surface area (SA) and high OSC performance. We enhanced the pyrochlore- ceria/zirconia (CZ) which has a very small SA. In order to enhance the heat resistance and promote the OSC reaction, we selected and optimized the additive element. This material showed high OSC performance especially in the temperature range of 400 degrees or less. Another key technology is washcoat structure that has high gas diffusivity by making connected pore in the washcoat (New pore forming technology).
Technical Paper

Development of CFD Inverse Analysis Technology Targeting Heat or Concentration Performance Using the Adjoint Method and Its Application to Actual Components

2018-04-03
2018-01-1033
To resolve two major problems of conventional CFD-based shape optimization technology: (1) dependence of the outcome on the selection of design parameters, and (2) high computational costs, two types of innovative inverse analysis technologies based on a mathematical theory called the Adjoint Method were developed in previous studies for maximizing an arbitrary hydrodynamic performance aspect as the cost function: surface geometry deformation sensitivity analysis to identify the locations to be modified, and topology optimization to generate an optimal shape. Furthermore, these technologies were extended to transient flows by the application of the transient Adjoint Method theory. However, there are many cases around flow path shapes in vehicles where performance with respect to heat or concentration, such as the total amount of heat transfer or the flow rate of a specific gas component, is very important.
Technical Paper

Development of New Continuously Variable Transmission for 2.0-Liter Class Vehicles

2018-04-03
2018-01-1062
Toyota has developed a new continuously variable transmission (CVT) called "Direct Shift-CVT" which is for 2.0-liter class vehicles. This CVT provided not only power transmission by a metal belt held with a conventional pulley but also additional gear mechanism. This CVT is developed to improve fuel efficiency, acceleration characteristic, and quietness. At this CVT, the startup low gear ratio is achieved by gear mechanism and the power is switched by clutches. Since the belt-pulley portion can be realized to be wide range by using only high gear ratio range, the input load into belt-pulley portion is reduced and unprecedented compact and high efficient belt-pulley portion is established. Consequently, the high efficiency in all fields from startup acceleration to high speed driving is achieved to improve fuel efficiency.
Technical Paper

Update of the WorldSID 50th Male Pelvic Injury Criterion and Risk Curve

2018-04-03
2018-01-0539
Petit et al. 2015 and Lebarbé et al. 2016 reported on two studies where the injury mechanism and threshold of the sacroiliac joint were investigated in two slightly oblique crash test conditions from 18 Post Mortem Human Subjects (PMHS) tests. They concluded that the sacroiliac joint fractures were associated with pubic rami fractures. These latter being reported to occur first in the time history. Therefore it was recommended not to define a criterion specific for the sacroiliac joint. In 2012, injury risk curves were published for the WorldSID dummy by Petitjean et al. For the pelvis, dummy and PMHS paired tests from six configurations were used (n = 55). All of these configurations were pure lateral impacts. In addition, the sacroiliac joint and femur neck loads were not recorded, and the dummy used was the first production version (WorldSID revision 1). Since that time, the WorldSID was updated several times, including changes in the pelvis area.
Technical Paper

New 2.0L I4 Gasoline Direct Injection Engine with Toyota New Global Architecture Concept

2018-04-03
2018-01-0370
Toyota Motor Corporation has developed a new 2.0L Inline 4- Cylinder (I4) Gasoline Direct Injection Engine, the second Naturally Aspirated (NA) engine of the Toyota New Global Architecture (TNGA) engine series, to meet our customers’ expectations for drivability, performance, and fuel economy. The high speed combustion technologies adopted previously in our 2.5 L NA conventional and Hybrid Vehicle (HV) engines for the 2018 Toyota Camry are necessary for high engine power and thermal efficiency. To adopt our high speed combustion technology on engines with different displacements, the turbulence intensity has been defined as the target index of combustion speed. The basic engine structure has been revised by using Computational Fluid Dynamics (CFD) analysis to achieve the combustion target.
Technical Paper

Development of a New 6-Speed FWD Manual Transmission

2018-04-03
2018-01-0392
Environmental awareness has increased on a global scale which pushed for a heavier demand for weight reduction and high transmission efficiency on manual transmissions (hereafter referred to as the “MT”) in improving vehicle driving and fuel economy performance. Comfortable shift feel is also continuously in demand by the customer because its sensitive performance can be directly recognized by the driver which may determine the transmission’s merchantability. The newly developed 6-speed MT (hereafter referred to as the “6MT”) has achieved size reduction (compact size), weight reduced, better fuel efficiency, and improvement in the shift feel which will continue to maintain its’ competitiveness in the future.
Technical Paper

A Java Implementation of Future Automotive Systems Technology Simulator (FASTSim) Fuel Economy Simulation Code Modules

2018-04-03
2018-01-0412
Future Automotive Systems Technology Simulator (FASTSim) is a free and open-source tool developed by National Renewable Energy Lab (NREL). Among the attractive capabilities of the FASTSim is that it can perform computationally efficient fuel economy simulations of automotive vehicles with reasonable accuracy for standard or arbitrary drive cycles. The modeling capability includes vehicles with various types of powertrains such as: conventional vehicles (CVs), hybrid-electric vehicles (HEVs), plugin hybrid electric vehicles (PHEVs) and battery-only electric vehicles (BEVs). The public version of FASTSim available from NREL is implemented in Excel, which achieves the goal of good accessibility to a broad audience, but has some limitations, including: i) bottleneck in computations when importing arbitrary drive cycles, ii) slower computations in general than other scripting or programming languages, and iii) less portable to integration with other applications and/or other platforms.
Technical Paper

Rubber Suspension Bushing Model Identified by General Design Parameters for Initial Design Phase

2018-04-03
2018-01-0693
This paper proposes a rubber suspension bushing model considering amplitude dependence as a useful tool at the initial design phase. Experiments were carried out to verify several dynamic characteristics of rubber bushings under vibration up to a frequency of 100 Hz, which is an important frequency range when designing ride comfort performance. When dynamic characteristic theory and the geometrical properties of the force-displacement characteristic curve were considered using these dynamic characteristics as assumptions, an equation was derived that is capable of calculating the dynamic stiffness under an arbitrary amplitude by identifying only two general design parameters (dynamic stiffness and loss factor) under a reference amplitude. The rubber suspension bushing model was then constructed by transforming this equation. Two verifications were carried out to confirm that the model is capable of reproducing measured bushing characteristics.
Technical Paper

Development of New Hybrid Transaxle for Mid - Size Vehicle

2018-04-03
2018-01-0429
The new P710 hybrid transaxle for a mid-size 2.5-liter class vehicle was developed based on the Toyota New Global Architecture (TNGA) design philosophy to achieve a range of desired performance objects. A smaller and lighter transaxle with low mechanical loss was realized by incorporating a new gear train structure and a downsized motor. The noise of the P710 transaxle was also reduced by adopting a new damper structure.
Technical Paper

Hybrid Navigation System That Combines Cloud and On-Board Computing

2018-04-03
2018-01-0022
A hybrid navigation system [1] that performs route calculations and highly flexible natural speech location searches in the cloud using dynamic databases that combine probe data collected from the vehicle and external data, and transmits to on-board devices has been developed. The system automatically switches to the on-board device when the vehicle is out of mobile network communication range or when faster processing is required for tasks such as re-routing. The transition between the on-board devices and the cloud provide a seamless user experience adapted to use conditions and other factors. In addition, representing the route downloaded from the cloud by the on-board device requires synchronizing the map with the cloud, and a map caching function has been used to reduce the volume of data that needs to be synchronized. The cloud-based route calculation is based not only on average travel time, but on dispersion as well.
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