Pressure Sensor Output Research Articles

Dynamic fault detection and isolation for automotive engine air path by independent neural network model

Fault detection and isolation have become one of the most important aspects of automobile design. A new fault detection and isolation scheme is developed for automotive engines in this paper. The method uses an independent radial basis function neural network model to model engine dynamics, and the modelling errors are used to form the basis for residual generation. Furthermore, another radial basis function network is used as a fault classifier to isolate occurred fault from other possible faults in the system by classifying fault characteristics embedded in the modelling errors. The performance of the developed scheme is assessed using an engine benchmark, the mean value engine model with Matlab/Simulink. Five faults have been simulated on the mean value engine model, including three sensor faults, one component fault and one actuator fault. The three sensor faults considered are 10–20% changes superimposed on the measured outputs of manifold pressure, manifold temperature and crankshaft speed sensors; the component fault considered is air leakage in the intake manifold; the actuator fault considered is the malfunction of fuel injector. The simulation results show that all the simulated faults can be clearly detected and isolated in dynamic conditions throughout the engine operating range.

Measurement and Calibration of the Displacement and Pressure in Automatic Wheelset Assembly Machine

This paper introduces the measurement systems of the oil cylinder in automatic wheelset assembly machine, theoretically analyzes the error of the displacement measurement system by curve fitting, and gets verification the error analysis in practice. This paper also calibrates pressure sensor from zero drift, slope of the output of the pressure sensor to guarantee the system pressure, and compensated pressure sensor value consistent.

Temperature Characteristic of Platinum Piezoresistive Pressure Sensor

Temperature characteristic of platinum piezoresistive atmosphere pressure sensor is studied in this paper, in which platinum is used as the sensing material and SU-8 is used as adhesive bonding layer. Normally, temperature variation will bring on resistance change of sensing platinum resistor with a linear relationship. Simultaneously, the thermal expansion mismatching in different material will also change the resistance. They both affect the temperature characteristic of sensor. Based on elasticity theory, the relationship between resistance change and thermal expansion mismatching is analyzed and is not linear. Sum of two parts resistance change is still nonlinear. Because the output of atmosphere pressure sensor is proportional to resistance change, relationship between output and temperature change is also nonlinear. The analysis is consistent with the experimental results.

Radial basis function neural network in fault detection of automotive engines

Fault detection and isolation have become one of the most important aspects of automobile design. A fault detection (FD) scheme is developed for automotive engines in this paper. The method uses an independent Radial Basis Function (RBF) Neural Network model to model engine dynamics, and the modelling errors are used to form the basis for residual generation. A dependent RBFNN model is a model which uses output data of a plant as a target output then use it to train the neural network, while, The independent RBFNN model is a higher accuracy than the dependent model and the errors can be detected by this model, this is because this model does not dependent on the output of the plant and it will use its output as a target, so if any faults in the plant will be not effect in the model and this faults will be detected easily and clearly. The method is developed and the performance assessed using the engine benchmark, the Mean Value Engine Model (MVEM) with Matlab/Simulink. Five faults have been simulated on the MVEM, including three sensor faults, one component fault and one actuator fault. The three sensor faults considered are 10-20% change superimposed on the outputs of manifold pressure, temperature and crankshaft speed sensors; one component fault considered is air leakage in intake manifold and Exhaust Gas Recycle (EGR); the actuator fault considered is the malfunction of fuel injector. The simulation results showed that all the simulated faults can be clearly detected in the dynamic condition throughout the operating range. Keywords: Automotive engine, independent RBFNN model, RBF neural network, fault detection International Journal of Engineering, Science and Technology, Vol. 2, No. 10, 2010, pp. 1-8

사출금형 버 발생 방지를 위한 형합면압 측정에 관한 연구

The flashing reduces the part quality and the productivity of the molding process. We developed a contact pressure sensor to detect the flashing immediately. The performance of the sensor was analyzed in a simple 2D simulation. The sensor was applied to an automotive bumper mold with cavity pressure sensors. It showed sensitive output signal for the mold response by the cavity pressure change. It was confirmed that the flashing at the gate area occurred in the filling stage by the pressure increase due to growth of the melt flow length. The sensor output was correlated with the cavity pressure sensor output.

Measurement for dissociation ratio of source gases in plasmas using a quartz sensor

The dissociation ratio of source gas molecules is measured using a quartz sensor, for which the output depends on the average molecular weight and viscosity of gases. The change in the pressure and temperature-normalized quartz sensor output (NQO) by discharge correlates with changes of the signal intensity of the source gas of ammonia (NH 3), as measured by gas analysis using a quadrupole mass spectrometer. Thereby, the dissociation ratio is obtainable from the change in NQO by the discharge. The spatial distributions of the change in NQO in the plasma chamber show a larger change in NQO near the plasma electrode, indicating that the change in NQO correlates with the dissociation ratio of NH 3. Finally, the dissociation ratios of NH 3 near and between the plasma electrodes were obtained from the spatial distribution of the dissociation ratio of NH 3. Results show that the Q-sensor measurement is simple and useful to derive the dissociation ratio of the source gases for the plasmas of reactive gases.

Clustered Active Noise Control in an Enclosure

This paper discusses the reduction of noise in a cavity from a viewpoint of cluster control. First, cluster filtering that enables the extraction of desired control information out of a set of sound pressure sensor outputs is presented. Cluster actuation classified as the duality of cluster filtering is then proposed, whereby activating only the target cluster among an infinite number of acoustic modes of a cavity. Using both the cluster filtering and actuation, clustered active noise control (C-ANC) is proposed, permitting one to suppress the targeted cluster independently. In contrast to a MIMO system conventional ANC generates, a C-ANC system comprises SISO systems, thereby reducing computation load on control effort significantly. With a view to elucidating the validity as well as potential C-ANC possesses, a rectangular cavity is introduced as a target structure where eight sensors/sound sources are provided for cluster filtering/actuation. It is found that acoustic potential energy of the cavity is grouped into eight clusters due to the cluster filtering, each sub-potential energy being suppressed independently because of the cluster actuation without causing any spillover.

A novel method to measure respiratory airflow rate based on nasal pressure

In this paper, a new method to measure respiratory airflow rate using the pressure inside a sealed nose has been described. The method is based on the Pitot tube principle and involves using a pressure microsensor connected to the sealed nasal cavity. There is no need to capture the total flow with a facemask. Promising initial results have been obtained, showing a high correlation between the pressure sensor output and the actual flow. Further work is required to alleviate errors associated with flow path geometrical variations.

Thermostatic control for temperature compensation of a silicon pressure sensor

An alternative temperature compensation technique for a silicon pressure sensor is presented. By using on-chip heater and temperature sensing electrodes, a thermostatic control loop is implemented. The sensor is biased at a reference temperature, which is maintained with high accuracy over a specified range, hereby eliminating the dependence of the pressure sensor output on ambient temperature. No additional calibration procedures for temperature compensation or external temperature sensing elements are required. Modelling aspects as well as experimental results are discussed.

SI Engine Closed-loop Spark Advance Control Using Cylinder Pressure

The introduction of inexpensive cylinder pressure sensors provides new opportunities for precise engine control. This paper presents a control strategy of spark advance based upon cylinder pressure of spark ignition engines. A location of peak pressure(LPP) is the major parameter for controlling the spark timing, and also the UP is estimated, using a multi-layer feedforward neural network, which needs only five pressure sensor output voltage samples at -40˚, -20˚, 0˚, 20˚, 40˚ after top dead center. The neural network plays an important role in mitigating the A/D conversion load of an electronic engine controller by increasing the sampling interval from 10 crank angle(CA) to 20˚ CA. A proposed control algorithm does not need a sensor calibration and pegging(bias calculation) procedure because the neural network estimates the UP from the raw sensor output voltage. The estimated LPP can be regarded as a good index for combustion phasing, and can also be used as an MBT control parameter. The feasibility of this methodology is closely examined through steady and transient engine operations to control individual cylinder spark advance. The experimental results have revealed a favorable agreement of individual cylinder optimal combustion phasing.

Innovative ambulatory drug delivery system using an electrolytic hydrogel infusion pump.

This report describes an ambulatory infusion device developed to provide parenteral drug delivery at a precisely controlled rate. The device is based on the innovative and unique concept of utilizing electrohydrolysis of a negatively charged hydrogel. The system consists of two modules: a pump unit and an electronic control unit. The pump module, which can be a disposable unit, contains medication separated by a flexible membrane from a gas generating chamber; this latter is an electrolytic cell comprising a hydrogel block and two platinum electrodes. The microcontroller-based control module is constructed with a user interface which includes input keys and a liquid crystal display, as well as a control to alter driving current level, depending on the infusion rate required. A microprocessor instantaneously calculates the current level required; this is based on operator-selected infusion rate, ambient pressure, and temperature sensor output. The accuracy and precision of the device were verified for all flow rates and for different environmental conditions; in vitro test results showed acceptable accuracy with less than +/- 5% error over the whole operating range of 0.1-100 [ml/h]. The device is small, lightweight, simple and easy to manufacture, and is also designed to be comfortably and conveniently worn by patients. It can be used for a variety of regimens including, for example, chemotherapy, insulin delivery, and pain management, antibiotic and AIDS therapy.

Application of aluminum films as temperature sensors for the compensation of output thermal shift of silicon piezoresistive pressure sensors

Aluminum thin film resistors are proposed for use as temperature sensors for the compensation of the thermal sensitivity and offset shift of pressure sensor output. An experimental investigation of Al films with different thicknesses and heat treatment was carried out in order to optimize the electric parameters of such temperature resistors. It was found that films with a thickness 1.2 μm and thermal etched at 330°C for 72 h have good long-time stability, a specific resistance of 2.85 μΩ cm and a temperature coefficient of resistance of 4.33 × 10 −3/°C. The obtained results indicate that Al resistors can be used in an electrical circuit for the passive temperature compensation of the thermal shift of pressure sensor output within a temperature range of up to 125°C.

Study on the measurement of oil-film pressure of engine main bearing by thin-film sensor — The influence of bearing deformation on pressure sensor output under engine operation

In a previous paper, oil-film pressure in an engine main bearing was measured by a using thin-film Manganin sensor. This sensor had adequate sensitivity to strain and temperature in terms of measurement principle. In this study, more accurate measurement of oil-film pressure was allowed by the formation of the newly developed thin-film strain sensor made of Ni-Cr-Al at the same location as that of the Manganin pressure sensor, and the correction of measurement errors caused by strain. The characteristics of bearing metal surface strain varied by engine operating conditions are also shown in this paper.

Field In-Ice Pressure Sensor Response Tests

An ice pressure sensor has been designed and built at Exxon Production Research Company (EPR) to measure the pressure in an ice sheet. Laboratory and analytical studies were performed to establish a data reduction procedure to relate the pressure sensor output to the pressure in the ice sheet. However, because of the complex mechanical behavior of sea ice, the present experiment was conducted to validate this data reduction procedure. The validated procedure is considered applicable to a broad class of embedded ice pressure sensors. Field in-ice pressure sensor response tests were conducted near Prudhoe Bay, Alaska, between February and April of 1978. Twenty-two tests were conducted on three test blocks of ice to investigate the in-ice response of three ice pressure sensors. An ice block measuring 10 ft by 20 ft and of full thickness of the natural annual ice was cut free from the surrounding ice sheet after the pressure sensor was installed at the center of the block. This ice block was loaded by an in-situ hydraulic ice loading device capable of delivering approximately two million lb of load. The pressure sensor output and the test load were monitored continuously during each test so that the pressure sensor output could be compared directly to the corresponding applied pressure. The test results indicated ratios of applied ice pressure to measured sensor pressure within the range hindcast by theoretical analysis.

Fault diagnosis for engine air path with neural models and classifier

Fault detection and isolation (FDI) have become one of the most important aspects of automobile design. A new FDI scheme is developed for automotive engines in this paper. The method uses an independent radial basis function (RBF) neural network model to model engine dynamics, and the modelling errors are used to form the basis for residual generation. A dependent RBFNN model is a model which uses output data of a plant as a target output then use it to train the neural network, while, The independent RBFNN model is a higher accuracy than the dependent model and the errors can be detected by this model, because this model does not dependent on the output of the plant and it will use its output as a target, so if any faults in the plant will be not effect in the model and this faults will be detected easily and clearly. Furthermore, another RBF network is used as a fault classifier to isolate different faults from the modelling errors. The method is developed and the performance assessed using the engine benchmark, the Mean Value Engine Model (MVEM) with Matlab/Simulink. Five faults have been simulated on the MVEM, including three sensor faults, one component fault and one actuator fault. The three sensor faults considered are 10-20% changes superimposed on the measured outputs of manifold pressure, manifold temperature and crankshaft speed sensors; one component fault considered is air leakage in intake manifold; the actuator fault considered is the malfunction of fuel injector. The simulation results show that all the simulated faults can be clearly detected and isolated in dynamic conditions throughout the engine operating range.