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Exhaust and noise emissions were successfully reduced using a Single Spray Direct Injection Diesel Engine (SSDI) on a two-liter naturally-aspirated four-cylinder engine. The compression ratio, the swirl ratio and the pumping rate were optimized to obtain good fuel economy, high power output and low exhaust emissions. Furthermore, through a modification of the fuel injection equipment, hydrocarbon (HC) emissions were reduced. Upon a test vehicle evaluation of this engine, more than 11% fuel savings relative to Mazda two-liter Indirect Injection Diesel Engines (IDI) were obtained. As for engine noise, structural modifications of the engine were carried out to obtain noise emission levels equivalent to IDI.

This paper presents the results of a study of how people interacted with a production voice-command based interface while driving on public roadways. Tasks included phone contact calling, full address destination entry, and point-of-interest (POI) selection. Baseline driving and driving while engaging in multiple-levels of an auditory-vocal cognitive reference task and manual radio tuning were used as comparison points. Measures included self-reported workload, task performance, physiological arousal, glance behavior, and vehicle control for an analysis sample of 48 participants (gender balanced across ages 21-68). Task analysis and glance measures confirm earlier findings that voice-command interfaces do not always allow the driver to keep their hands on the wheel and eyes on the road, as some assume.

MIT Lincoln Laboratory is tasked by the U.S. Federal Aviation Administration to investigate the use of the NEXRAD polarimetric radars* for the remote sensing of icing conditions hazardous to aircraft. A critical aspect of the investigation concerns validation that has relied upon commercial airline icing pilot reports and a dedicated campaign of in situ flights in winter storms. During the month of February in 2012 and 2013, the Convair-580 aircraft operated by the National Research Council of Canada was used for in situ validation of snowstorm characteristics under simultaneous observation by NEXRAD radars in Cleveland, Ohio and Buffalo, New York. The most anisotropic and easily distinguished winter targets to dual pol radar are ice crystals.

A method of analyzing the three-dimensional sound field in a full-size automobile cabin was studied. The acoustic resonant frequency and the acoustic mode of the cabin were calculated by using the boundary element method (BEM), and were then compared with an experiment conducted on a full-size cabin model made of plaster. The calculated resonant frequencies agreed with measured ones to within about 3% below 170 Hz, and the calculated modes and frequency response curves were in good agreement with experiments when the cabin wall was rigid. In the case of a wall partially lined with absorbing materials, the calculated resonant frequency and the damping ratio were approximately the same as the experimental ones. From these studies, it is concluded that the BEM is useful for analyzing the sound field in a full-size automobile cabin.

As a demand for vehicles of higher functionality grows, automakers and material suppliers are devoting increasing efforts to develop technologies for greater safety, lighter weight, higher corrosion resistance, and enhanced quietness. The resin-sandwiched vibration damping steel sheet (VDSS), developed as a highly functional material for reducing vehicle vibration and noise, has been used for oil pans1) and compartment partitions2). First applied for a structural dash panel of the new Mazda 929, a Zn-Ni electroplated VDSS which allows direct electric welding has contributed to greater weight reduction as well as improved quietness.

The primary objective in design is to achieve the target value of the design's response function. If a design fails to achieve the target value, it most likely fails in two ways: inconsistent functional output and in design involving multiple response functions, unable to converge to the multiple target values in spite of iterative adjustment of the design parameters. The former is symptom of a design not able to perform in the presence of variability, i.e., noise. The latter is symptom of a design that fails to perform in the presence of functional coupling. Both problems are best addressed at the conceptual stage of the design at which only design solution that is inherently robust to noise and functionally uncoupled is entertained. If this is not possible, the alternative is to exploit the interaction between control variables and variables that are sources of noise and functional coupling to render the design insensitive to them.

Reliable means for on-board detection of particulate filter failures or malfunctions are needed to meet diagnostics (OBD) requirements. Detecting these failures, which result in tailpipe particulate matter (PM) emissions exceeding the OBD limit, over all operating conditions is challenging. Current approaches employ differential pressure sensors and downstream PM sensors, in combination with particulate filter and engine-out soot models. These conventional monitors typically operate over narrowly-defined time windows and do not provide a direct measure of the filter’s state of health. In contrast, radio frequency (RF) sensors, which transmit a wireless signal through the filter substrate provide a direct means for interrogating the condition of the filter itself.

A method to inspect the rattle generated in a vehicle cabin has been developed. In the method, the waveform of overall in-cabin noise is analyzed using Wigner distribution, a kind of time-frequency analysis, and the rattle component of the waveform is condensed and separated from the background shake noise. Then the rattle component is classified into three levels, strong, middle and not detected, using a neural network. Fuzzy inference is also used to select normal waveform data. Experimental results show that the correct classification ratio of the method is more than 90%, which equals the ability of skilled inspectors.

The Cu-zeolite (CuZ) SCR catalyst enables higher NOx conversion efficiency in part because it can store a significant amount of NH3. “NH3 storage control”, where diesel exhaust fluid (DEF) is dosed in accord with a target NH3 loading, is widely used with CuZ catalysts to achieve very high efficiency. The NH3 loading actually achieved on the catalyst is currently estimated through a stoichiometric calculation. With future high-capacity CuZ catalyst designs, it is likely that the accuracy of this NH3 loading estimate will become limiting for NOx conversion efficiency. Therefore, a direct measurement of NH3 loading is needed; RF sensing enables this. Relative to RF sensing of soot in a DPF (which is in commercial production), RF sensing of NH3 adsorbed on CuZ is more challenging. Therefore, more attention must be paid to the “microwave resonance cavity” created within the SCR assembly. The objective of this study was to develop design guidelines to enable and enhance RF sensing.

Mazda established an original design methodology combining a capacitive coupling technology and transmission line theory, to develop a high performance window antenna for AM/FM radios which construction is very simple to construct and requires no use of any antenna boosters or matching circuits. This paper introduces the design methodology and performance characteristics of the new antenna as well as its application to the production '95 model Mazda 929.

To realize high levels of handling, driving performance, and NVH characteristics for a sports car, it is important to develop a lightweight and high-stiffness vehicle body. For the new RX-7, weight saving and higher stiffness were pursued as top priorities from the very first stage of the program. We were able to achieve 20% higher bending stiffness and 15% higher torsional stiffness with vehicle weight reduced by 30 kg, compared with the former model. The development of the lightweight, high-stiffness body for the new RX-7 is discussed under three subjects: 1. Contributions of vehicle components to vehicle stiffness 2. Effective procedure for developing vehicle high stiffness and lightweight construction with emphasis on calculation analysis 3. New RX-7's body structure and accomplishment

The objectives of this work were to establish a method to diagnose the source of gear rattle and to evaluate the rattle objectively. The methods are described in detail, applied to two passenger cars as an example. Investigations were conducted into transmission rattle under transient conditions. By analysing the transmission casing vibration with respect to the engine flywheel angle, and presenting the data in the form of contour maps, it was shown that the two vehicles had different characteristics of gear impacts. Further measurements of the angular motion of each gear revealed the impact conditions at the input mesh in the transmission largely controlled the character of the rattle and were fundamentally different between the two vehicles. A rattle index was developed, based on the casing vibration under transient driving conditions.

It has been required recently that diesel engines for passenger cars meet various requirements, such as low noise, low fuel consumption, low emissions and high power. The key to improve the noise is to reduce a combustion noise known as “Diesel knock noise”. Conventional approaches to reduce the diesel knock are decreasing combustion excitation force due to pilot/pre fuel injection, adding ribs to engine blocks or improving noise transfer characteristics by using insulation covers. However, these approaches have negative effects, such as deterioration in fuel economy and increase in cost/weight. Therefore, modification of engine structures is required to reduce it. We analyzed noise transfer paths from a piston, a connecting rod, a crank shaft to an engine block and vibration behavior during engine operation experimentally, and identified that piston resonance was a noise source.

Reducing cold-start emissions to meet increasingly stringent emissions limits requires fast activation of exhaust system sensors and aftertreatment control strategies. One factor delaying the activation time of current exhaust sensors, such as NOx and particulate matter (PM) sensors, is the need to protect these sensors from water present in the exhaust system. Exposure of the ceramic sensing element to water droplets can lead to thermal shock and failure of the sensor. In order to prevent such failures, various algorithms are employed to estimate the dew point of the exhaust gas and determine when the exhaust system is sufficiently dry to enable safe sensor operation. In contrast to these indirect, model-based approaches, this study utilized radio frequency (RF) sensors typically applied to monitor soot loading levels in diesel and gasoline particulate filters, to provide a direct measurement of stored water levels on the ceramic filter elements themselves.

Cost and weight reduction considerations make it very important to evaluate and reduce aerodynamic noise in the early stage of vehicle develpment. For these reasons, a method to evaluate aerodynamic noise quantitatively is needed. As an initial step, our first paper investigated airflow around the A-pillar of a full-scale vehicle. As a result, vortical flow structure and the influence of the vortical flow on the pressure fluctuations were clarified. As the second step, this paper presents an estimation method for the aerodynamic noise from a vehicle. Based on Lighthill's equation, we propose an evaluation equation to estimate aerodynamic noise. The aerodynamic noise radiated externally from a vehicle is estimated as ∑(Pfi,fi,Sfi)2 Where Pfi is the fluctuating pressure on the surface of the vehicle, fi the frequency and Sfi the correlation area. The method is applied to the aerodynamic noise problem associated with the A-pillar of a vehicle.

The increasing use of diesel and gasoline particulate filters requires advanced on-board diagnostics (OBD) to prevent and detect filter failures and malfunctions. Early detection of upstream (engine-out) malfunctions is paramount to preventing irreversible damage to downstream aftertreatment system components. Such early detection can mitigate the failure of the particulate filter resulting in the escape of emissions exceeding permissible limits and extend the component life. However, despite best efforts at early detection and filter failure prevention, the OBD system must also be able to detect filter failures when they occur. In this study, radio frequency (RF) sensors were used to directly monitor the particulate filter state of health for both gasoline particulate filter (GPF) and diesel particulate filter (DPF) applications.

Efficient aftertreatment management requires accurate sensing of both particulate filter soot and ash levels for optimized feedback control. Currently a combination of pressure drop measurements and predictive models are used to indirectly estimate the loading state of the filter. Accurate determination of filter soot loading levels is challenging under certain operating conditions, particularly following partial regeneration events and at low flow rate (idle) conditions. This work applied radio frequency (RF)-based sensors to provide a direct measure of the particulate filter soot levels in situ. Direct measurements of the filter loading state enable advanced feedback controls to optimize the combined engine and aftertreatment system for improved DPF management. This study instrumented several cordierite and aluminum titanate diesel particulate filters with RF sensors. The systems were tested on a range of light- and heavy-duty applications, which included on- and off-road engines.

A high compression ratio is an effective means for improving the thermal efficiency of an internal combustion engines. However, a high compression ratio leads to a rapid rise in the combustion pressure, as it causes a high impulse force. The impulse force generates vibrations and noise by spreading in the engine. Therefore, reducing the vibration of the combustion (which increases as the compression ratio increases) can improve the thermal efficiency while using the same technology. We are conducting model-based research on technologies for reducing combustion vibration by applying a granular damper to a piston. To efficiently reduce the vibration, we suppress it directly with the piston, i.e., the source of the vibration. Thus, the damping effect is maximized within a minimized countermeasure range.

The combustion process after auto-ignition is investigated. Depending on the non-uniformity of the end gas, auto-ignition could initiate a flame, produce pressure waves that excite the engine structure (acoustic knock), or result in detonation (normal or developing). For the “acoustic knock” mode, a knock intensity (KI) is defined as the pressure oscillation amplitude. The KI values over different cycles under a fixed operating condition are observed to have a log-normal distribution. When the operating condition is changed (over different values of λ, EGR, and spark timing), the mean (μ) of log (KI/GIMEP) decreases linearly with the correlation-based ignition delay calculated using the knock-point end gas condition of the mean cycle. The standard deviation σ of log(KI/GIMEP) is approximately a constant, at 0.63. The values of μ and σ thus allow a statistical description of knock from the deterministic calculation of the ignition delay using the mean cycle properties

This paper describes the thermal management and design challenges of testing packaged integrated circuit (IC) devices, specifically device thermal conditioning and device-under-test (DUT) temperature control. The approach taken is to discuss the individual thermal design issues as defined by the device type (e.g. memory, microcontroller) and tester capabilities. The influence of performance-parameter specifications, such as the DUT parallelism, test time, index time, test-temperature range and test-temperature tolerance are examined. An understanding of these performance requirements and design constraints enables consideration of existing test handler thermal processing systems (e.g., gravity feed, pick and place), future test handler thermal concepts, and future high-parallelism testing needs for high-wattage memory and microprocessor devices. New thermal designs in several of these areas are described.