Combustion Pressure Sensor Research Articles

Sensor Technologies for Automobiles and Robots

AbstractThis paper reviews various sensor technologies with application in automobiles and robots. Several automotive sensors have been developed using the micro‐electromechanical systems (MEMS) technology. The technologies related to combustion pressure sensors, yaw rate sensors, acceleration sensors, and optical scanners are described here. The combustion pressure sensors are used for engine control, while the yaw rate sensors of quartz and silicon crystals and the acceleration sensors are applied for vehicle motion control. Optical scanners are developed for autonomous driving. Several automotive sensors have been significantly reduced in size and cost, and their performance has been improved dramatically by MEMS technology. The inertial force‐sensing system with yaw rate and acceleration sensors enabled the assistant and partner robots to stand on two legs, walk, or invert and move on two wheels. Because the robots are required to have a variety of sensors, a nerve‐net sensing system was developed. This sensing system has three layers: the host, relay, and sensor nodes. The sensor node is a special large‐scale integration called a ‘nerve‐net chip.’ A triaxial force tactile sensor integrated with the nerve‐net chip was developed as a 2.8‐mm square surface‐mountable chip. A force and thermal tactile sensor was also developed, which detected heat flows and discriminated the materials of contacted objects. The heat flow sensor was thinned with thin‐film technology. The sensor technologies will be used for eco cars and autonomous vehicles. Next‐generation robots are also supported by several automotive sensor technologies. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Real-time assessment of in-cylinder pressure for fresh air mass estimation using the example of modern spark-ignited combustion engines

This article describes an approach suitable for real-time application, which enables the estimation of the trapped air mass in the cylinder of a modern spark ignition engine using the information of a combustion pressure sensor. First of all, different criteria are derived and assessed from the in-cylinder pressure signal. Then, an empirical model on the basis of engine test bench measurements is developed. Finally, the results of the methods are compared with cylinder and cycle individually to a reference air mass, which is obtained by the engine measurements and a subsequent zero-dimensional low-pressure-based air mass calculation.

Control of the Combustion Process Parameters in ICE by the Ion Current Signals

This paper is devoted to control of the combustion processes in the internal combustion engines (ICE). It presents a method for estimation of the position of the peak pressure, the maximal pressure of the cycle and the air-fuel ratio based on the analysis of the integral characteristics of the ion current signals. The advantages of the proposed method are stability of the final result of the calculation to the influence from the cycle-to-cycle combustion parameter variations, stability to the changes in the parameters of the measuring probe during a long operation time and absence of restrictions on the wave form of the ion current. It also presents the results of the experimental testing of the developed method and its comparison with the conventional methods of analysis of the ion current and control of the combustion process parameters. The authors compared the efficiency and accuracy of the method using a combustion pressure sensor, based on the piezoelectric ceramics; the methods of the ion current analysis, based on detection of the thermal-ionization ion current peak; the method of the ion current analysis based on the integral characteristic of the ion current signal. The results of the experimental studies indicate a possibility of the use of the integral characteristic of the ion current signal for estimation of the combustion process parameters with the accuracy of the combustion pressure sensor based on the piezoelectric ceramics. The ion current measurement technology is cheaper than the piezoelectric ceramic sensors and can be widely applied in the serial engines.

SEC Method-based Engine Combustion Pressure Sensor

SEC Method-based Engine Combustion Pressure Sensor

The influence of the ignition system characteristic on the two-stroke engine operating conditions

This paper presents an indicator analysis of the impact of the characteristics of an electronic ignition system on the operating conditions of a two-stroke spark ignition engine. The tests were carried out on a single-cylinder two-stroke engine equipped with a combustion pressure sensor using the apparatus for recording fast-varying signals. The influence of changes of the ignition angle of advance at constant engine speeds on the engine operating indicators was analysed. The assessment of the impact of the changes to the settings of the ignition system was analysed in terms of thermodynamic conditions: combustion pressure and average effective pressure. It was found that the ignition angle of advance has positive influence on engine operating conditions and uniformity of engine operation. As a measure of non-uniformity of engine operation were accepted the coefficient of variation of the engine speed and the mean indicated pressure. It was indicated that, along with the ignition angle of advance, the indicators of two-stroke engine operation also increase with simultaneous increase in the non-uniformity of engine operation. Keywords: two-stroke engine, ignition system, combustion, thermodynamic analysis

G0700707 20cc水素ロータリーエンジンの性能に及ぼす点火時期の影響

Hydrogen has been attracting attention as a useful fuel to improve state of environmental pollution and resource depletion by using fossil fuels. In internal combustion engines, which are widely used as conventional technologies, the hydrogen fuel can be applied. Since minimum ignition energy of hydrogen is lower than that of other fuels, the hydrogen fuel tends to cause abnormal combustion. However, the abnormal combustion is easily controlled in a rotary engine. In this study, therefore, a hydrogen rotary engine (HRE) was developed. For improving stability and output power of the 20cc HRE, combustion pressure sensor was adopted to measure combustion pressure in the 20cc HRE. Combustion pressure of the 20cc HRE at high load was decreased with delay of the ignition timing. Maximum torque was 0.24 Nm at BTDC 5 °. Exhaust gas temperature of the 20cc HRE was increased with delay of the ignition timing. On the other hand, thermal efficiency of the 20cc HRE was improved.

Calcium aluminate silicate Ca2Al2SiO7 single crystal applicable to piezoelectric sensors at high temperature

Ca2Al2SiO7 (CAS) bulk single crystals were grown by the Czochralski method. Material constants of the crystal were determined over the driving temperature range of a typical combustion pressure sensor. The electrical resistivity at 800 °C was found to be of the order of 108 Ωcm. We constructed a measurement system for the direct piezoelectric effect at high temperature, and characterized the crystals in a simulated engine cylinder combustion environment. Output charge signal against applied stress was detected at 700 °C. These observations suggest that CAS crystals are superior candidate materials for high temperature for stress sensing.

Piezoelectric properties of langasite group based on the ionic size of cation

As langasite A3BC3D2O14 compounds group with piezoelectric properties has no phase transition up to the melting point of 1400–1500°C, they have been applied for the combustion pressure sensor. As they also have a larger electromechanical coupling factor compared to quartz and nearly the same temperature stability as quartz, the surface acoustic wave (SAW) filters are expected based on the digital transformation of wider bandwidth and higher-bit rates. In the case of three-element compounds such as [R3]A[Ga]B[Ga3]C[GaSi]DO14 (R=La, Pr and Nd), the piezoelectric constant increases with the ionic radius R. In the case of four-element compounds such as [A3]A[B]B[Ga3]C[Si2]DO14 (A=Ca or Sr, B=Ta or Nb), |d11| and k12 values as a function of AL/BL ratio showed a linear relationship completely. There are two effects for the substitutions of A- and B-site cations: the substitution of Sr for Ca brings expansion toward [100] and enlargement in |d11| and k12. On the other hand, as the substitution of Ta for Nb brings not much change, the properties are similar. In this study, five-element compounds such as La3−xSrxTayGa5−x+ySi1+x−2yO14 (0≤x≤3, 0≤y≤1) solid solutions analysed by a single crystal X-ray diffraction are compared with the three- and four-element compounds on the coordinates of oxygen ions. As the coordinates positions are located on the extended line of coordinate positions on the three-element compounds as increasing ionic radius of R-ions in A-site, the piezoelectric properties |d11| and k12 are expected become large.

Mechanism of Piezoelectricity for Langasite Based on the Framework Crystal Structure

Piezoelectric langasite crystals have superior properties such as high temperature performance and high quality Q and can be applied in combustion pressure sensors and surface acoustic wave (SAW) filters. Crystal growth, crystal structure and properties of langasite group are reviewed, and the mechanism of piezoelectricity of langasite is presented based on the crystal structure and deformation under high pressure. Finally, for the discovery of new piezoelectric materials, this paper presents the role of the framework, and recommends the search of framework crystal structure, because the characteristic of the mechanism exists on the framework of the crystal structure.

Development of a pressure sensor using a piezoelectric material thin film

In this paper, we show the process of research and development of a combustion pressure sensor using an aluminum nitride (AlN) thin film, which we developed for the first time in the world. At the time we envisaged the R&D in 2003, most sensors used a piezoelectric single crystal. The research of a combustion pressure sensor using an AlN thin film was an unexplored field, and the usefulness of an AlN thin film was not yet well recognized. However, since we started the R&D, domestic and foreign auto parts companies and universities showed interest, and we carried out joint research with a domestic company and a university toward practical use of the sensor. Consequently, we have succeeded in developing a sensor of small size, high sensitivity, and without the need of cooling. We now conduct research to resolve the problems such as stabilization of sensor signals and simplification of the sensor structure for practical use.

Cylinder Head Gasket with Integrated Combustion Pressure Sensors for Advanced Engine Controls

Cylinder Head Gasket with Integrated Combustion Pressure Sensors for Advanced Engine Controls

Combustion Pressure Sensors Using C-axis-oriented Zinc Oxide Thin Films Prepared on Inconel Substrates

C-axis-oriented zinc oxide (ZnO) thin films were prepared on Inconel substrates by rf magnetron sputtering technique. The ZnO film characteristics were evaluated under pressures of 10.0 to 300.0 MPa and frequencies of 0.1 to 30 Hz at room temperature. The deviation from the linearity of charges with pressures for the ZnO films was within 0.52 % of a full scale at 300.0 MPa, which indicated a good linearity between 10.0 and 300.0 MPa. Furthermore the ZnO films were evaluated under combustion pressure in a single-piston 90 cc engine rotating at 1900 rpm. The waveform of the ZnO films was similar to those of a commercial sensor. It is demonstrated that the ZnO films have a good possibility as combustion pressure sensor elements.

Combustion Pressure Sensors using C-axis-oriented Aluminum Nitride Thin Films Prepared on Inconel Substrates

C-axis-oriented aluminum nitride (AlN) thin films were prepared on Inconel substrates by the rf magnetron sputtering technique. The full-width at half-maximum (FWHM) of the X-ray rocking curve of the AlN films was 5.7°, and the piezoelectric constant d33 was 2.4 pC/N. The deviation from the linearity of charges with pressures for the AlN films were 0.2% of a full scale at 0.4 MPa, which indicated a good linearity. Furthermore the AlN films was evaluated under combustion pressures in a single-piston 90 cc engine rotating up to 4000 rpm. The waveforms of the AlN films were similar to those of a commercial sensor. It is demonstrated that the AlN films have a good possibility as combustion pressure sensor elements.

Automotive Sensors and MEMS Technology

Abstract - Automotive sensors are used for emission gas purification, energy conservation, car kinematic performance, safety and ITS (intelligent transportation system). The comparison of the sensor characteristics was made for their application area. Many kinds of the principles are applied for the sensors. There are two types of sensors, such as physical and chemical one. Many of the automotive sensors are physical type such as mechanical sensors. And a gas sensor is a chemical type. The sensors have been remarkably developed with the advancement of the MEMS (Micro Electro Mechanical Systems) technology. In this paper, gas, pressure, combustion pressure, acceleration, magnetic, and angular rate sensors for automotive use are explained with their features.The sensors are key devices to control cars in the engine, power train, chassis and safety systems. The environment resistance, long term reliability, and low cost are required for the automotive sensors. They are very hard to be resolved. However, the sensor technology contributes greatly to improving global environment, energy conservation, and safety. The applications of automotive sensors will be expanded with the automobile developments.

Design of An IC Engine Torque Estimator Using Unknown Input Observer

The torque produced by each combustion in an engine is one of the most important indices tied to internal combustion engine performance. In this paper, an approach is investigated to estimate engine torque. Instead of employing expensive and delicate combustion pressure sensors to directly measure indicated pressure in each cylinder, unknown input observers are exploited to estimate cylinder indicated torque using one or more low-cost measurements of crankshaft angular position. Necessary and sufficient conditions for the existence of such torque estimators for multi-cylinder engines are presented in the paper; these include the number of angular position sensors required and their suggested placement. Model reduction issues and the number of measurements required to obtain an acceptable estimate are also considered. The approach is applied to a six-cylinder industrial diesel engine.

Heteroepitaxial growth of 3C-SiC on SOI for sensor applications

Typical industrial high temperature sensor applications are reviewed and a short overview of the different high temperature sensor technologies is given. The pros and cons are weighted. Silicon carbide on insulator (SiCOIN) technology comes out to be the most attractive, provided the state of development can be brought up to the one of silicon and silicon on insulator (SOI). Due to the lack of commercially available SiC on SOI wafers, a new SiC on SOI technology has been developed. It is based on the precursor gas methylsilane. The low temperature growth process is described and in-situ n-type doping, which is necessary for sensor applications, has been carried out successfully over a wide range of concentrations without loosing the good crystal properties. Actually the full process is being transferred from a test reactor to a 4 inch machine. This should provide 3C-SiC on SOI wafers for commercial sensor applications. A demonstrator of combustion pressure sensor dedicated to pressure-based engine control is shown. Results of the pressure sensor fitted in a motor-test setup are summarized.

Silicon compatible materials for harsh environment sensors

The wide bandgap semiconductors silicon carbide and diamond and the material system Silicon On Insulator (SOI) are compared regarding their suitability as silicon compatible materials to extend the application fields of micromachined sensors to harsh environment conditions especially to high temperatures. The harsh environment conditions are specified by analyzing the demands of automotive and aerospace applications. The physical properties of the material systems are discussed and their technological stage of development is evaluated, especially with respect to the compatibility to standard silicon processes. Furthermore, the commercial availability of the different materials in the form of substrates is considered and a forecast of future developments is attempted. As an example of a harsh environment sensor, a combustion pressure sensor is presented and characterized.

Kalman Filtering, An Effective Method for Different Applications in A/F Ratio Control

In this paper, three applications of Kalman filters for A/F ratio control in SI engines are presented. The filters deal with the problem of cylinder air mass estimation in different approaches: signal filtering for perturbation reduction of the manifold pressure signal, sensor data fusion and adaptive Kalman filtering using a combustion pressure sensor. We want to emphasis, that the Kalman filter is a high effective method for A/F ratio control.

Improved Temperature Dependence of Piezoelectric Element for Pressure Sensor

The temperature dependence of the d33 constant was decreased by connecting a piezoelectric element to a temperature compensating capacitor in series. A bilayered composite piezoelectric element consisting of piezoelectric and dielectric ceramic layers was constructed to reduce the temperature dependence of the d33 constant. The temperature dependence of the d33 constant was thus reduced to less than 3% over the temperature range of -30 to 180° C. Furthermore, the temperature dependent properties of a combustion pressure sensor for an automobile engine based on the composite piezoelectric element developed in this study were discussed.

New generation of automotive sensors to fulfil the requirements of fuel economy and emission control

The new passenger car regulations for future emission levels and the increasing demands for fuel economy have led to strong efforts to develop new engine-management systems, exhaust-treatment technologies and new automotive sensors. In this paper a new generation of automotive sensors that help to fuffil the requirements for fuel economy and emission control is presented. The demands on these new sensors include the following improvements: (i) better resolution, higher accuracy and better long-term stability, especially under severe environmental conditions; (ii) good performance at high temperature (e.g., up to 150 °C for rotational speed sensors and 1100 °C for exhaust gas sensors); (iii) short response times for dynamic cylinder-selective measurements; (iv) more efficient compensation methods by measuring different physical parameters. This talk gives an overview on the physical principle, the design, the technology and the application of a new generation of automotive sensors. Representing a potential ‘high-volume’ sensor, we report on an active rotational speed sensor to measure the angular position of the crankshaft. This sensor is based on a newly developed differential Hall IC. The high angular resolution allows more accurate ignition timing as well as ‘misfiring’ detection to be achieved. For the precise control of combustion in future engine-management systems, an ‘air flow sensor’ for cylinder-specific carburation, a ‘combustion pressure sensor’ for thermodynamic calculation of the combustion and a ‘fast exhaust gas sensor’ for cylinderselective exhaust-gas analysis can be used. This report will focus on the development of a fast oxygen sensor to measure the oxygen partial pressure of the exhaust gas. As an example of a smart sensor, an ‘alcohol fuel sensor’ for alternative fuel concepts is introduced. This sensor is a key component of a flexible fuel system which can be run on arbitrary mixtures of gasoline and methanol. This sensor measures three physical parameters: the capacitance, the conductivity and the temperature, in order to determine the methanol/gasoline ratio in the fuel rail with high accuracy.