Knock Sensor Research Articles

Women’s Security Using Wrist Band

Nowadays, women and children safety is a prime issue of our society. The count of the victim is increasing day by day. In this paper, we are proposing a model which will develop a self defense system especially for women to ensure the safety and to protect themselves from present day physical harassments. We have used different sensors like the knock sensor, temperature sensor, 3-axis accelerometer. We have also used GPS which will help to detect the location of the device. GSM used in the model is used to send the alert message to predefined number, police station. We have proposed embedded microcontroller based device ARDUINO which will help to continuously monitor values of different sensors and GPS used in the device.

신호처리를 이용한 노크센서의 엔진진동 측정에 대한 연구

To measure engine vibrations, an additional accelerometer must be installed. However, selecting the measurement position is difficult to and requires additional cost. In contrast, the knock sensor is a sensor that detects the knocking of the engine. It has a piezo resistor, which is inserted in the knock sensor, that can turn these vibrations into voltage. In this study, we measured engine vibrations by using the knock sensor. The acceleration sensor and the knock sensor were simultaneously mounted and used to measure the engine vibrations. The measured signals were compared via signal processing to investigate whether the knock sensor can be a possible alternative to the accelerometer for engine vibration measurement.

Combustion Ionization for Detection of Misfire, Knock, and Sporadic Preignition in a Gasoline Direct Injection Engine

Detection of combustion-related phenomena such as misfire, knock, and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions. This paper applies several types of combustion ionization sensors, and a pressure transducer that directly senses the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four-cylinder gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a piezo quartz pressure transducer, MSFI (multi-sensing fuel injector), a stand-alone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles, the spark plug sensor and MSFI appear to be the most favorable, followed by the stand-alone mounted sensor which is an addition to the engine.

α- & β-crystalline phases in polyvinylidene fluoride as tribo-piezo active layer for nanoenergy harvester

The manuscript introduces the use of non-electrically polled spin-coated thin polyvinylidene fluoride (PVDF) films as the active layers in a contact electrification-based nanoenergy harvester. The four-layered device utilizes both piezo and triboelectric effect coupled with electrostatic induction. The elucidation of potential generation during contact between crystalline phases ( α and β) of PVDF layer material is investigated in the manuscript. Fourier transform infrared–attenuated total reflectance spectroscopy is carried out to illustrate the α- and β-phases in PVDF pellet, prepared film as well as the film after contact. Dynamic contact mode electrostatic force microscopy (DC-EFM) along with atomic force microscopy is used for the evaluation of reverse piezoelectric, local ferroelectric, triboelectric voltage and adhesive energy of the PVDF films before–after contact process. Quantum chemical calculation is performed using density functional theory to explain possible electron transitions in the active layers between the cylindrically symmetric α-phase and electrical double layer charges in the β-phase of PVDF. The interface study of the film is also carried out both experimentally using DC-EFM and through quantum chemical calculations. The fabricated device with the hybrid piezo-tribo layer promises to be a simple and low-cost energy source for the next-generation self-powered electronic devices. The device can also be used as knock sensor in engines as well as a capacitor.

Identification of combustion and detonation in spark ignition engines using ion current signal

The identification of combustion and detonation in spark ignition (SI) engines is very important to its control within optimized and efficient boundaries. While they are generally identified respectively by phase and knock sensors, this investigation provides additional evidences that the ion current could be used as a sensing device to replace those two sensors, in order to identify both phenomena. The cylinder under combustion could be determined with the ion current signal, by sampling and computing the area under the signal curve. In order to monitor detonation, the correlation between the energy of a frequency band of the ion current signal and the energy of the knock sensor signal was established. The results indicated the viability to use the ion current to detect combustion and detonation in several situations, such as variations in the fuel mixture, mileage of the spark plug, and area size of the spark plug electrode.

Analysis of Engine Knock Sensor

The paper deals with design of a simple device for the detection of this disorder. In the beginning of the paper the effect of the undesirable detonation combustion in internal combustion engines is described. An engine control unit monitors these detonations using piezoelectric knock sensors. With the control of these sensors the detonations can be objectively measured just outside the car on the test panels. If this component provides small amplitude of the output voltage it could happen that it would have been in the areas of the engine ignition combustion.

Mega knock detection and inhibition system for turbo GDI engine

Mega knock is an inevitable and destructive combustion phenomenon in gasoline engine, and the tendency of mega knock occurring in GDI turbocharged engine is more serious than other engine. So in order to protect the engine, a system which can detect mega knock and inhibit the occurrence of consecutive mega knock is proposed in this paper. Firstly, the knock sensor signal is translated to the integral value, and it is identified that whether a mega knock has happened based on the integral value. Finally, some methods such as fuel enrichment will be taken to inhibit mega knock in the next cycle. The experiment results of HIL verify that this system can detect mega knock occurrence accurately, and it is indicated by the thermodynamics theorem that the inhibit strategy is reasonable.

Evaluation of a Knock Sensor for Gearbox Diagnosis

A gearbox is one of the critical components in rotating machinery. Timely prediction of gearbox faults become of great importance to minimizing unscheduled machine downtime. Most of gearbox diagnosis studies are focused on the development of gearbox diagnosis algorithms using costly vibration sensors. However, vibration sensor cost matters in some applications, thus pushing to the use of a low-cost accelerometer, such as a knock sensor. This study develops a sensor evaluation process for the purpose of diagnosis. This study uses a planetary gearbox with a knock sensor, known to be cheap and good for high frequency applications (i.e., diesel engines). First, gearbox feature engineering is thoroughly studied through time domain and frequency domain analyses. This study uses the features that are most sensitive to gearbox faults, such as pitting and surface damages. Second, some sensor evaluation metrics (i.e., signal-to-noise ratio (SNR)) are overviewed for the purpose of diagnosis. The sensor evaluation study suggests a frequency range of the knock sensor that can be reliably used for fault diagnosis. Two case studies are presented to demonstrate the effectiveness of the proposed sensor evaluation process and metric: 1) one-stage planetary gearbox and 2) a swing reduction gear (two-stage planetary gearbox) in an excavator. It is concluded that a knock sensor can be used for the fault diagnosis of a gearbox.

Vibroactivity analysis of a dual fuel diesel engine based on the knock sensor signal and measuring pressure in the combustion chamber

A study conducted by a team of authors attempts to identify the occurrence of knocking based on the vibro-acoustic signal from the knock sensor and the signal from the pressure sensor glow plug (PSG). The reason the authors decided to discuss the issue is increasing interest in the use of information contained in the generated vibration and acoustic emissions as well as reducing acoustic emissions as one of the environmental threats. The adopted form of experiment and analysis enables determining the validity of testing of NVH multifuel engines. Information based on the vibro-acoustic signal allows to determine the qualitative and quantitative occurrence of the phenomenon of knocking in case of proper analysis. Both the energy spectrum of the vibration and the summation value of the successive bands of the spectrum confirm the occurrence of knock resulting from the analysis of the pressure in the combustion chamber and allow to relate to its intensity.

Reliability Estimation for Accelerated Life Tests Based on a Cox Proportional Hazard Model with Error Effect

In this paper, a Cox proportional hazard model with error effect applied on the study of an accelerated life test is investigated. Statistical inference under Bayesian methods by using the Markov chain Monte Carlo techniques is performed in order to estimate the parameters involved in the model and predict reliability in an accelerated life testing. The proposed model is applied to the analysis of the knock sensor failure time data in which some observations in the data are censored. The failure times at a constant stress level are assumed to be from a Weibull distribution. The analysis of the failure time data from an accelerated life test is used for the posterior estimation of parameters and prediction of the reliability function as well as the comparisons with the classical results from the maximum likelihood estimation. Copyright © 2017 John Wiley & Sons, Ltd.

Vibration characteristics of disk-type piezoelectric knock sensor fixed at its center

Vibration characteristics of disk-type piezoelectric knock sensor fixed at its center

Engine performance testing using variable RON95 fuel brands available in Malaysia

There are various gasoline fuel producers available in Malaysia. The effects of fuel variations from different manufacturers on vehicle performance have always been a debate among users and currently the facts still remains inconclusive. Hence, this study focuses on analyzing various RON95 fuel brands available in the Malaysian market and finding the differences towards engine performance. In terms of engine output, the important data of power (hp) and torque (Nm) will be gathered by using an engine dynamometer. Another data that would also be taken into account is the knocking where the relative knock index can be measured in percentage using the knock sensor accelerometer. Results have shown that the performance of different fuel brands tested are indeed different albeit by only a small margin even though all fuels are categorized with the same octane rating. The power and torque results also imply that both are influenced by the amount of vibration generated due to engine knocking. Based from the overall outcome, consumers would not need to only focus on a certain type of gasoline brand as all differentiates the engine performance marginally.

Experimental and vehicle (on road) test investigations of spark-ignited engine performance and emissions using high concentration of MTBE as oxygenated additive

We study the effect of increasing methyl-tert butyl ether in regular gasoline (15, 25 and 51% volume) on the performance and combustion characteristics of spark ignited engines. A single cylinder engine, spark ignited was used. The engine in fully instrumented in order to measure all the relevant parameters, i.e. temperatures, pressures, exhaust emissions, intake air and fuel flows and indicating parameters like mass burned fuel. Results were compared with those obtained with a fleet of five model year 2003–2010 passenger cars. For that purpose FTP-74 tests were performed for the fuel containing 25% MTBE and compared with those obtained with the regular commercial gasoline. The gasoline-MTBE at 25% blend presents the lowest dispersion among the tested fuels, and the evolution of the instantaneous pressure with respect to the crank angle for each fuel, pointed out that no misfires occurred. The fuel with high contents MTBE (Blends 2 and 3) burn slightly later than the fuels formulated with typical MTBE contents around 11% volume. On the average, fuel economy seems to decrease as MTBE increases in accordance with the results observed using the single cylinder engine. Our results shows no immediately adverse effects when the MTBE contents increases up to 51%, and a small reductions in NOx as the MTBE contents increases. The octane requirement of the tested vehicles may be controlled by the knock sensors that adjust the engine operating. Clearly the use of high contents of ethers (i.e. between 25 and 30% MTBE in volume) as a fuel constituent represents an alternative for fuel decarbonization in Mexico and can be an alternative way to reduce the use of fossil fuels.

Comparison of spectral analysis of vibration using commercial knock sensor and 3-axis acceleration sensor

With the development of internal combustion engines, engineers attempt to reduce the noise and vibration generated. Due to the high cost of fuel, are increasingly looking for new sources of power in order to reduce costs. In diesel engines, an increasingly popular method is the admixture of propane-butane. This follows because of the price of the fuel as well as to improve the efficiency of combustion. With the development of this type of dual fuel power seems to be a reasonable study of the effects of LPG to generate noise and vibration, as well as an attempt to evaluate the combustion process. Unfortunately, too much addition of LPG causes a phenomenon called knock consisting in abnormal, uneven, explosive combustion of fuels in reciprocating engines. This phenomenon may lead to a reduction in engine performance and permanent damage. Control of the knock detection uses vibration acceleration sensors recording the high frequency ranges. Within the framework of the research conducted by the team of authors, an attempt was made to compare the vibroacoustic signals originating from the commercial knocking sensor with a three-axis acceleration sensor. These signals were subject to a quick Fourier transform in the purpose of analysing the amplitude spectra.

Normalized Knock Intensity Determination Based on the Knock Sensor Analysis to Have a Fixed Detection Threshold at Different Operating Conditions

Processing the knock sensor's signal is the most common approach for knock detection in series production vehicles. Filtration, rectification, and integration in a defined knock window (KW) are main steps to compute the standard knock intensity (SKI). The SKI strongly depends on the engine operating conditions. In this study, a novel model is proposed based on the knock sensor analysis to determine the normalized knock intensity (NKI) with much less dependency on the operating conditions, cylinder numbers (CNs), and KW. Implementing the proposed normalization model, a fixed detection threshold can be used for knock detection at all operating conditions. To verify the model, an accurate knock detection method based on cylinder pressure analysis is utilized, which comprises intensity calculation and a novel technique for detection threshold determination. Experimental results at all operating conditions show a square of correlation coefficient greater than 0.7 when the knock intensity from the presented model is compared with the reference cylinder pressure based method. In addition, the model detects all heavy knocking cycles and there is no wrongly detected knocking combustion.

An Innovation in the Field of Street Lighting System with Cost and Energy Efficiency

Background/Objectives: This paper focus on the necessity of automated street light system and the peculiar way of implementation with embedded system tools. As automation booming in the industry with a fast pace, the requirement of replacing the primitive operation of street lights with quite intelligence is necessary. Methods/Statistical Analysis: The previous systems were implemented with LDR and IR sensors, here the presence of movement in the roads are sensed by IR sensors and LDR powers the street lights only after evening. The excess use of IR sensors and energy involved in the above operation are reduced in our prototype. Here we use piezo electric sensors to detect the movement in the roads instead of IR sensors. The microcontroller MSP430 as the brain to control the processes involved 1 . Results/Findings: The results are found to be very encouraging and the sample results are presented in the results section of the paper. Conclusion/ Application: LEDs are going to be vital lighting option in near future due to its peculiar low power consumption and cost effective nature. Our prototype will help in eliminating the current sodium vapour street lamps with better LED comprised lamps operated smartly using LDR, and piezo knock sensor.

Sensor for analysis of engine knock control system

This paper deals with the phenomenon of the undesirable detonation combustion in internal combustion engines. A control unit of the engine monitors these detonations using piezoelectric knock sensors. With the control of these sensors the detonations can be objectively measured just outside the car. If this component provides small amplitude of the output voltage it could happen that there would have been in the areas of the engine ignition combustion. The paper deals with design of a simple device for the detection of this disorder.

Detecting the combustion phase and the biodiesel blend using a knock sensor

Existing methods of detecting the combustion phase of a diesel engine are mainly based upon high-cost in-cylinder pressure sensors. This paper presents a method of estimating the location of 75% of the mass fraction burned by using the traditional knock sensor signal. It is observed through experimental data that the knock signal has a close correlation to the location of 75% of the mass fraction burned. In this study, the knock integration is used to represent the knock intensity, while the piecewise knock integration (integration over a crank angle of 1°) is used to detect the location of 75% of the mass fraction burned. The proposed estimation method was validated using the experimental data and provided an accurate estimation of the location of 75% of the mass fraction burned. In addition, the feasibility of using the knock sensor signal to detect the biodiesel content is demonstrated using experimental data.

On applying the knock sensor for injector calibration

This article investigates the possibility of utilizing the standard knock sensor for an in situ injector calibration. The goal is to estimate the actual injection duration by means of the structure-borne sound emission during the injection process. Since the sound signals are highly nonstationary and contain various transients, a time–frequency analysis is applied. Based on the findings of the signal analysis, a method is presented for detecting the beginning and the end of injection by applying the theory of the change-point problem.

An Interface from LabVIEW to the Knock Sensor Testing System

This paper proposes how to use a domestic data acquisition card to develop a car knock sensor testing and analysis system, which is based on the U.S. NI LabVIEW. The content of the testing section is to design a driver based on the dynamic link library, aimed at making a communication between LabVIEW and the data acquisition card. This system can realize real-time acquisition for the knock sensor output signal, and the testing interface is simple and practical.