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Technical Paper

Measurement Techniques for Angular Velocity and Acceleration in an impact Environment

The University of Virginia is investigating the use of a magnetohydrodynamic (MHD) angular rate sensor to measure head angular acceleration in impact testing. Output from the sensor, which measures angular velocity, must be differentiated to produce angular acceleration. As a precursor to their use in actual testing, a torsional pendulum was developed to analyze an MHD sensor's effectiveness in operating under impact conditions. Differentiated and digitally filtered sensor data provided a good match with the vibratory response of the pendulum for various magnitudes of angular acceleration. Subsequent head drop tests verified that MHD sensors are suitable for measuring head angular acceleration in impact testing.
Technical Paper

Development of Multi-use Road Simulator

A multi-use road simulator for reproducing various road loads on motorcycles and buggies has been developed on a test bench by using computer-controlled hydraulic actuators. The device is controlled by a low-priced personal computer and an interface system with custom software. An unique feature is the capability to simulate loads related to such phenomena as the bottoming of suspension and the movement of a telescopic type front fork on the road.
Technical Paper

Some Considerations on Air Bag Restraint System Design

Crash sensors for the air bag system may be broadly divided into mechanical and electronic devices. The mechanical sensor is based on the idea to balance an external force working on the mass against a bias force which is basically proportional to the displacement of the mass. The characteristics of such bias force can be brought very close to an optimum state by properly designing the sensor system. Studies are also well under way on the relationship between damping and mass displacement to make it satisfy the requirements for the air bag system. The electronic sensor features the capability of changing its characteristics through a computer program. The positioning of sensors in the vehicle should be decided on taking their characteristics into consideration. In addition to the crash tests required under the applicable laws and regulations, we have elected to conduct a series of other tests simulating a variety of crash modes that may occur on the road.
Technical Paper

Investigation and Improvement of Interfacial Delamination in In-Situ Measuring Sensor for Automobile Application

Thin film sensors are often used for in-situ measuring. They are composed of a sensor/conductor layer and insulation layers on either side. However, delamination often occurs between the insulation layers and the sensor/conductor layer and makes the sensor life span shorter. This problem is found especially when there is continuous stress caused by the cyclic change of temperature, sliding and tension. By observing the microstructure of the sensor with transmission electron microscope (TEM), it was found that the adhesion force at the interface between the insulation layer and the sensor/conductor layer, where delamination occurs, is not strong enough, because the interface is too flat. By deposition a thin insulator layer with rough surface on the normal insulation layer, the delamination was successfully suppressed.
Technical Paper

A Study of PGM-Free Oxidation Catalyst YMnO3 for Diesel Exhaust Aftertreatment

Manganese oxides show high catalytic activity for CO and HC oxidation without including platinum group metals (PGM). However, there are issues with both thermal stability and resistance to sulfur poisoning. We have studied perovskite-type YMnO₃ (YMO) with the aim of simultaneously achieving both activity and durability. This paper describes the oxidation activity of PGM-free Ag/i-YMO, which is silver supported on improved-YMO (i-YMO). The Ag/i-YMO was obtained by the following two methods. First, Mn⁴+ ratio and specific surface area of YMO were increased by optimizing composition and preparation method. Second, the optimum amount of silver was supported on i-YMO. In model gas tests and engine bench tests, the Ag/i-YMO catalyst showed the same level of activity as that of the conventional Pt/γ-Al₂O₃ (Pt = 3.0 g/L). In addition, there was no degradation with respect to either heat treatment (700°C, 90 h, air) or sulfur treatment (600°C to 200°C, total 60 h, 30 ppm SO₂).
Technical Paper

Study of Piston Pin Noise of Semi-Floating System

This paper summarizes the piston pin noise mechanism and show the way to reduce noise level of semi-floating system. A mechanism of piston pin noise of semi-floating system was clarified by measurement of piston and piston pin behavior and visualization of engine oil mist around piston and piston pin. Piston and piston pin behavior was measured by accelerometer and eddy current type gap sensor with linkage system at the actual engine running condition. Engine oil behavior was visualized and measured its flow vector by Particle Tracking Velocimetry (PTV). For PTV, engine oil mist particle image was taken by high speed camera with fiber scope attached to linkage system. From themeasurement, it was cleared that engine oil doesn't reach to piston hole from undersurface of piston land and come rushing out from piston broach via groove. The result shows that lacking of engine oil between piston and piston pin makes noise larger.
Technical Paper

Development of Intake Air Pressure Sensorless Fuel Injection System for Small Motorcycles

A new control system using O₂ feedback control has been developed as an alternative to intake air pressure sensors. This control method uses the operational condition compensation coefficient Kbu. This coefficient encompasses the state of the engine and environmental conditions such as atmospheric pressure, and corrects fuel injection in response to changes in these factors. Kbu makes it possible to control the amount of fuel injection without depending on an intake air pressure sensor. It also makes it possible to carry out the appropriate air-fuel ratio correction even at times when O₂ feedback control is not operating, such as the cold period, when the engine is first started, or during transient operation, by using Kbu values recorded in the Engine Control Unit (henceforth ECU).
Technical Paper

Development of a Target Sensitivity Function based A/F F/B Controller by Sensor Response Characteristics

Recently, automotive emission regulations are being further tightened, such as the Tier III/LEV III in the U.S. As a result, reducing cost of after-treatment systems to meet these strict regulations has become an urgent issue, and then the demand for high-precision air-fuel ratio (A/F) control which can achieve this cost reduction is high [1]. On the other hand, in order to meet rapidly changing market needs, it is becoming difficult to keep enough development periods that enable sufficient calibration by trial-and-error, such as feedback-gain calibration. This leads to an increase in three-way catalytic converter costs in some cases. For these reasons, it is necessary to construct control system that can make full use of hardware capabilities, can shorten development periods regardless of the skill level of engineers.
Technical Paper

Development of Torque Sensor with Nickel-Iron Alloy Plating for Pedal-Equipped Electric Vehicles

This paper describes the development of non-contacting detection type torque sensor that realizes a small lost motion with light weight and low cost. Pedal-equipped electric vehicles are becoming popular in recent years. In those vehicles, torque sensors are usually necessary for measuring the pedaling force to determine the motor torque. We applied an integrated sensing structure and a non-contacting scheme utilizing inverse-magnetostrictive material to minimize the lost motions. As for the sensing material, nickel-iron alloy plating was used to obtain a wide dynamic range. In the tests using the actual structure, the output linearity deterioration occurred because of the strain distribution dispersion produced by the ratchet drive structure. Therefore, the effect of this strain distribution was examined. The inverse-magnetostrictive sensing material of nickel-iron alloy plating has an extremum on its output curve.
Technical Paper

Development of High-Power-Density DC-DC Converter Using Coupled Inductors for Clarity Plug-In Hybrid

Honda has developed an electric powertrain for a 2017 plug-in hybrid vehicle using its second-generation SPORT HYBRID i-MMD powertrain system as a base. The application of the newly developed powertrain system realizes a long all-electric range (AER), allowing operation as an EV for almost all everyday driving scenarios, with dynamic performance making it possible for the vehicle to operate as an EV across the entire speed range, up to a maximum speed of 100 mph. The amount of assist provided by power from the batteries during acceleration has been increased, helping to downsize the engine while also balancing powerful acceleration with quietness achieved by controlling racing of the engine. In order to realize this EV performance with the second-generation SPORT HYBRID i-MMD system as the base, it was necessary to increase the power output of the DC-DC converter, taking restrictions on space into consideration.
Technical Paper

Secondary O2 Feedback Using Prediction and Identification Type Sliding Mode Control

Recently, much research has been carried out on secondary O2 feedback which performs control based on the output from a secondary O2 sensor (HEGO sensor). In this research it has been found that, regardless of catalyst aging conditions, the HEGO sensor output indicates 0.6 V when the catalyst reduction rate is maintained at the optimum level. Therefore, based on this relationship, we designed an accurate secondary O2 feedback with the aim of reducing emissions by stabilizing the HEGO sensor output to 0.6 V. In order to realize this control, it was necessary to solve the three problems of nonlinear catalyst characteristics, dead time characteristics, and changes in dynamic characteristics due to catalyst aging conditions. Therefore, these problems were solved using the modeling approach of robust control and a new robust adaptive control named Prediction and Identification Type Sliding Mode Control.
Technical Paper

On-board Diagnostic Expert System via an Enhanced Fault Tree Model

We propose to enhance reliability based diagnosis by enhancing the fault tree model with a sensor layer for capturing evidence. We recognized the need for an automated diagnostic process that can predict and report component failure in vehicles prior to total failure of any system in the vehicle. We also want to take advantage of evidence that can be derived from sensors to reduce the amount of tests required to identify failed components.
Journal Article

Degradation Analysis of Pouch Cell Using High-Energy Cathode Material for Advanced Lithium-ion Battery

Lithium-rich layered oxide, expressed as xLi2MnO3-(1-x) LiMO2 (M = Ni, Co, Mn, etc.), exhibits a high discharge capacity of 200 mAh/g or more and a high discharge voltage at a charge of 4.5 V or more. Some existing reports on cathode materials state that lithium-rich layered oxide is currently the most promising candidate as an active material for high-energy-density lithium-ion cells, but there are few reports on the degradation mechanism. Therefore, this study created a prototype cell using a lithium-rich layered cathode and a graphite anode, and analyzed the degradation mechanism due to charge and discharge. In order to investigate the causes of degradation, changes in the bulk structure and surface structure of the active material were analyzed using high-resolution X-ray diffraction (HRXRD), a transmission electron microscope (TEM), X-ray absorption fine structure (XAFS), and scanning electron microscope/energy dispersive X-ray spectroscopy (SEM-EDX).
Journal Article

External Biofidelity Evaluation of Pedestrian Leg-Form Impactors

Current state-of-the-art vehicles implement pedestrian protection features that rely on pedestrian detection sensors and algorithms to trigger when impacting a pedestrian. During the development phase, the vehicle must “learn” to discriminate pedestrians from the rest of potential impacting objects. Part of the training data used in this process is often obtained in physical tests utilizing legform impactors whose external biofidelity is still to be evaluated. This study uses THUMS as a reference to assess the external biofidelity of the most commonly used impactors (Flex-PLI, PDI-1 and PDI-2). This biofidelity assessment was performed by finite element simulation measuring the bumper beam forces exerted by each surrogate on a sedan and a SUV. The bumper beam was divided in 50 mm sections to capture the force distribution in both vehicles. This study, unlike most of the pedestrian-related literature, examines different impact locations and velocities.
Journal Article

Application of Engine Load Estimation Method Using Crank Angular Velocity Variation to Spark Advance Control

The technology to estimate engine load using the amplitude of crankshaft angular velocity variation during a cycle, which is referred to as “Δω (delta omega)”, in a four-stroke single-cylinder gasoline engine has been established in our former studies. This study was aimed to apply this technology to the spark advance control system for small motorcycles. The cyclic variation of the Δω signal, which affects engine load detection accuracy, was a crucial issue when developing the system. To solve this issue, filtering functions that can cope with various running conditions were incorporated into the computation process that estimates engine loads from Δω signals. In addition, the system made it possible to classify engine load into two levels without a throttle sensor currently used. We have thus successfully developed the new spark advance system that is controlled in accordance with the engine speed and load.
Journal Article

Improving Earpiece Accelerometer Coupling to the Head

As accurate measuring of head accelerations is an important aspect in predicting head injury, it is important that the measuring sensor be well-coupled to the head. Various sensors and sensor mounting schemes have been attempted in the past with varying results. This study uses a small, implantable acceleration sensor pack in the ear to study impact coupling with the human skull. The output from these ear-mounted accelerometers is compared to laboratory reference accelerometers rigidly attached to the skull of two cadaveric head specimens for both low-amplitude oscillatory tests and high-amplitude impact drop tests. The combination of sensor type and mounting scheme demonstrates the feasibility of using ear mounted sensors to predict head acceleration response. Previously reported progressive phase lag was not seen in this study, with the comparison between ear mounted accelerometers and rigidly mounted head accelerometers ranging from very good to excellent.