A comparative study of the detection of the fuel-injection start and stop timing of a diesel injector using a photo sensor, a shock sensor and a needle lift sensor

Seong Jae Park,이충훈 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

The fuel-injection start and stop timings of a diesel injector were measured using a photo sensor, a shock sensor, and a needle lift sensor. The fuel spray jet was detected by installing a photo sensor at the position closest to the fuel spray jet exiting the diesel injector nozzle hole. The shock sensor was mounted outside of the injector holder assembly and the fuel injection timing was measured by detecting the shock wave generated when the injector needle moved. The injector needle lift was measured by using an injector with a built-in needle lift sensor (TDI G80 sensor). The G80 sensor has an integrated solenoid allowing the detection of the movement of the injector needle. As the injector needle moves, an electrical signal is induced from the solenoid and the voltage is measured. The photo sensor, shock sensor, and needle lift sensor all confirm that the timing of the start of fuel injection by the injector can be accurately measured. The fuel injection stop timing could be measured by the photo sensor and the needle lift sensor. The variation of the fuel injection stop timing was greater than that of the fuel injection start timing. The shock sensor could not accurately measure the fuel injection stop timing. The detecting time order of the start of the fuel injection by the three sensors was in order of the needle lift sensor, the shock sensor and the photo sensor.

포토 센서와 충격 센서를 이용한 디젤 솔레노이드 인젝터 연료 분사 시작 및 종료 타이밍 측정

박성재,이충훈 대한기계학회 2023 大韓機械學會論文集B Vol.47 No.11

디젤 솔레노이드 인젝터를 제어하여 연료를 분사하였을 때, 연료 분사 시작과 종료 타이밍을 광센서 및 충격 센서를 사용하여 측정하였다. 인젝터 노즐팁 최근접 위치에 광센서를 설치하여 분무를 감지하였다. 인젝터 바디 바깥쪽에는 충격 센서를 장착하여 인젝터 내 니들의 움직임을 감지하였다. 광센서와 충격 센서에 의한 연료 분사 시작 타이밍의 정확한 측정이 가능함을 확인하였다. 연료 분사 종료 타이밍은 광센서로는 측정이 가능하였으나 충격 센서로는 불가능하였다. 연료 분사 패턴은 단발 분사와 파일롯 분사 2가지를 사용하였다. 단발 분사로 연료를 분사할 때에는 연료 레일압을 45 MPa, 75 MPa, 105 MPa 3 케이스로 제어하였다. 파일롯 분사의 경우에는 75 MPa로 제어하였다. 측정 데이터의 통계적 처리를 위해서 하나의 실험 조건에서 35회씩 반복 측정하였다. 불확실성 해석에 필요한 에로 분포 함수는 정규 분포를 사용하였다. The start and end timings of a controlled fuel injection in a diesel solenoid injector were measured using photo and shock sensors. The photo sensor was installed near the tip of the injector nozzle to measure the spray. The shock sensor was installed outside the injector body to detect the movement of the injector needle. It was confirmed that the fuel injection start timing could be accurately measured by both the photo and shock sensors, while the fuel injection end timing could be measured only by the photo sensor. Two types of fuel injection patterns, namely single and pilot injections, were investigated. In the single injection, the fuel rail pressure was controlled at values of 45, 75, and 105 MPa. On the other hand, in the pilot injection, the pressure was set to 75 MPa. To aid in the statistical processing, the measurements were repeated 35 times under one experimental condition. For the uncertainty analysis, a normal distribution was assumed for the error distribution function.

스파크플러그형 압력 센서의 특성 비교 및 분석

위효성(Hyoseong Wi),박진일(Jinil Park),이종화(Jong-hwa Lee) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

A cylinder pressure data is used with an important factor to evaluate the efficiency of engine system. There are many article about measuring the cylinder pressure. Spark plug type pressure sensor can be installed to the engine without the configuration about below from engine experiment. But, the precision of the sensor diminishes when it is exposed to the high temperature condition compliance with an intermittent fire it gets of combustion it happens. In order to solve this problem, water cooling type direct mount pressure sensor can be used. However this sensor has some weak points. One is a problem of installing sensors. For using this type of sensors, a cylinder head of a test engine must be processed. It needs much money, time and efforts. Another is a problem of extra equipment such as water pump, chiller and hoses. These make it impossible the experiment of vehicle on a road. Most recently, a pressure sensor company developed a new spark plug pressure sensor designed for thermal shock reduction. In this study, experiment is performed to evaluate thermal shock effect of conventional spark plug sensor based on water cooled direct mount sensor. And also the new spark plug sensor is compared with standard spark plug sensor to evaluate the improved performance. It can be used to rate the reliability of the experiment.

광센서 및 충격 센서에 의한 디젤 솔레노이드 인젝터의 연료 분사 시작 및 종료 타이밍 측정 결과 비교 연구

박성재(Seongjae Park),이충훈(Choonhoon Lee) 한국자동차공학회 2021 한국자동차공학회 부문종합 학술대회 Vol.2021 No.6

점화 장치가 없는 디젤 엔진 연료 분사 시작 타이밍 및 분사 패턴은 가솔린 엔진의 점화 타이밍과 유사하게 엔진 성능에 큰 영향을 미친다. 디젤 엔진 ECU에는 엔진 속도 및 부하 조건에서 최적의 연료 분사 시작 타이밍과 분사 패턴이 mapping 된다. 연료 분사 시작 타이밍이 진각되면 smoke emission은 줄어들고 NOx emission 증가하여 두 배기 가스는 상호 trade-off relationship을 가진다. 기계식 연료 분사 시스템을 사용하는 디젤 엔진과 달리 커먼 레일과 전자 제어 인젝터를 사용하는 최근의 디젤 엔진은 연료분사 시작 타이밍 제어에 제약이 없다. 즉, 어떤 엔진 조건에서도 원하는 타이밍에 연료를 분사하고 분사를 종료할 수 있다. 또한 커먼 레일 디젤엔진은 기계식 연료 분사시스템에서는 매우 어려운 pilot injection, multiple injection 등의 정확한 분사 시작 타이밍 제어가 가능하다. 본 연구에서는 디젤 솔레노이드 인젝터를 제어하여 연료를 분사하였을 때, 연료 분사 시작과 종료 타이밍을 광센서, 충격 센서를 사용하여 측정하였다. 인젝터 nozzle tip 최근접 위치에 광센서를 설치하여 spray를 감지하였다. 인젝터 body 바깥쪽에는 충격 센서를 장착하여 injector needle의 움직임을 감지하였다. 광센서와 충격 센서에 의한 연료 분사 시작 타이밍 측정은 정확하게 측정이 가능함을 확인하였다. 연료 분사 종료 타이밍은 광센서로는 측정이 가능하였으나 shock sensor로는 불가능하였다. 연료 분사 패턴은 single injection과 pilot injection의 2가지를 사용하였다. Single injection으로 연료를 분사할 때에는 45 MPa, 75 MPa, 105 MPa 3case rail pressure으로 제어하였다. pilot injection의 경우에는 75 MPa rail pressure 만으로 제어하였다. 측정 데이터의 통계적 처리를 위해서 하나의 실험 조건에서 35회씩 반복 측정하였다. Uncertainty analysis를 위한 error distribution 함수로는 normal distribution function을 사용하였다.

Improvement of the instability of compressible lattice Boltzmann model by shockdetecting sensor

Vahid Esfahanian,Mohsen Ghadyani 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.5

Recently, lattice Boltzmann method (LBM) has drawn attention as an alternative and promising numerical technique for simulatingfluid flows. The stability of LBM is a challenging problem in the simulation of compressible flows with different types of embeddeddiscontinuities. This study, proposes a complementary scheme for simulating inviscid flows by a compressible lattice Boltzmann modelin order to improve the instability using a shock-detecting procedure. The advantages and disadvantages of using a numerical hybrid filteron the primitive or conservative variables, in addition to, macroscopic or mesoscopic variables are investigated. The study demonstratesthat the robustness of the utilized LB model is improved for inviscid compressible flows by implementation of the complementaryscheme on mesoscopic variables. The validity of the procedure to capture shocks and resolve contact discontinuity and rarefaction wavesin well-known benchmark problems is investigated. The numerical results show that the scheme is capable of generating more robustsolutions in the simulation of compressible flows and prevents the formation of oscillations. Good agreements are obtained for all testcases.

Experimental study of boundary layer in compressible flow using hot film sensors through statistical and qualitative methods

A. A. Haghiri,N. Fallahpour,M. Mani,M. Tadjfar 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11

The boundary layer state, laminar, transitional or turbulent, greatly affects an aircraft’s aerodynamic performance, specifically the skinfriction force. In the present research, the characteristics of the boundary layer and the transition region have been studied experimentallythrough the statistical methods (RMS and Skewness), and also qualitative and frequency analysis using hot film sensors output. The testshave been performed at Mach numbers from 0.25 to 0.85 with the maximum Reynolds number of 11.6 million per meter, and the maximumangle of attack of 9° on a supercritical airfoil. The validation of the methods mentioned, which are usually used for incompressibleflow, has been investigated for compressible flow with shock waves with detailed assessment. Results have shown that in the shock- freecase, the boundary layer regions are identifiable by statistical analysis such as RMS and Skewness, as in incompressible flow. However,in the presence of shock waves, because of sudden, local and instantaneous changes in the output voltage level of hot films, determinationof the dominant pattern in the boundary layer becomes impossible using the RMS of the total data. Therefore, first, the signal must bedivided into different regions and then, with identifying the cause of voltage fluctuations in each region and its effect on the behavior ofthe steady state boundary layer, appropriate intervals for RMS calculation can be determined. The frequency analysis is valid and can beused in all conditions tested. In these tests the trip strip performance in forming forced transition was also evaluated (through using hotfilms and pressure coefficient distribution) and the characteristics of the boundary layer were studied. Results have illustrated that the tripstrip, forced transition, compared with the free transition, causes sudden boundary layer turbulence, limitation of the transitional region, achange in the shock structure and pressure distribution.

홉킨슨 압력봉(Hopkinson pressure bar)을 이용한 동적 충격센서 보정기술 연구

오세욱 ( Se-wook Oh ),민경조 ( Gyeong-jo Min ),조상호 ( Sang-ho Cho ) 대한화약발파공학회 2020 화약발파 Vol.38 No.1

The measurement technique with dynamic shock sensor was widely used in academic experiment for blasting and impact. However, most of dynamic sensors are expensive so that it needs to be protected by external housing structures or damping devices. In this study, the calibration method for dynamic shock sensor under the distortion by external structures. Hopkinson pressure bar system was adopted to measure the input acceleration to the sensor, and it was compared to the acceleration measured by accelerometer with customized damping device. Consequently, it is conclued that this method can be useful to calibrate the dynamic shock sensor under the linear distortion.

군용차용 전자광학 추적 시스템 영상 센서 장치의 충격 응답에 관한 연구

이상은(Sang Eun Lee),박형건(Hyung Gun Park),이태원(Tae Won Lee) 대한기계학회 2018 大韓機械學會論文集A Vol.42 No.4

군용차량에 탑재되어 운용되는 전자광학 추적 시스템의 일부분인 영상 센서 장치는 내부 짐발과 외부 짐발 및 전자부품들의 조립체인 센서모듈로 구성된다. 차량으로부터 전달되는 충격이 이 장치에 가해지면 영상의 선명도, 표적 추적에 영향을 미칠 뿐 아니라 심한 경우 장치 파손 또는 기능 저하를 유발할 수 있다. 그러므로, 이를 고려한 규격으로 MIL-STD-810G w/Change 1충격 가속도 조건이 선택되었다. 시스템의 안전 설계를 달성하기 위하여 기초부에 충격 가속도를 받는 영상 센서 장치의 과도 응답을 유한요소법으로 수치 계산하였다. 그리고 유한요소 모델과 동일 충격 조건으로 시제품에 실험을 수행하여 제안된 해석 방법의 유용함을 입증하였다. An electro-optical targeting system mounts on a military vehicle and includes an image sensor unit. The unit is made of an inner gimbal, an outer gimbal, and a sensor module, having many electronic parts. Shock is transmitted from the vehicle to the unit, affecting image sharpness and target-tracking. If the shock is excessive, damage or performance degradation may occur to the unit. Thus, the shock acceleration condition of MIL-STD-810G w/Change 1 are used to evaluate the equipment under these circumstances. To achieve a safety design for the system, the transient response is numerically calculated by the finite element method for the image sensor unit subjected to shock acceleration at the base. Additionally, experiments are performed with a prototype under the same shock conditions as the finite element model, proving that proposed numerical method is useful.

탄환 충격파 측정용 방수 음향센서 개발

허신,Duck-Gyu Lee 한국센서학회 2019 센서학회지 Vol.28 No.5

In shooting training, an impact point identification system that uses the impact wave of the bullet to check the impact point in the target plate has been recently used. Acoustic sensors used in these systems must be able to detect shock waves of high sound pressure levels and be both waterproof and dustproof for rainy weather and dusty environments, respectively. In this study, membranes with excellent waterproof, dustproof, and sound transmitting characteristics were selected through a characteristics test; a protection cap was installed to install the selected materials. After coupling the produced protection cap to the acoustic sensor housing, the sensitivity and phase characteristics of the acoustic sensor were checked. Through the waterproof and dustproof test, the performances of its sensitivity and phase characteristics were confirmed. Finally, the normal shockwave of a 5.56 mm diameter bullet was measured using a shockwavedetection signal collecting plate equipped with a prototype of the acoustic sensor at a 100 m firing range.

쇽 펄스 센서를 이용한 저속 축 베어링의 결함 검출

양영훈(Young-Hun Yang),이중혁(Joong-Hyeok Lee),박선미(Sun-Mi Park),김석현(Seockhyun Kim) 대한기계학회 2018 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.6 No.2

메가와트 급의 대형 풍력터빈은 매우 낮은 속도로 장시간 회전하면서 전력을 생산한다. 터빈에 사용되는 베어링은 반복 하중에 장시간 노출되면서 결함이 발생하기 쉬운 요소이다. 큰 고장을 사전에 방지기 위해서는 베어링의 결함을 초기에 진단하는 것이 중요하다. 그러나 축의 회전속도가 낮고 하중이 작을 때, 작은 결함에서 내는 미세한 이상 진동은 일반적인 가속도계로는 그 검출이 쉽지 않다. 쇽펄스 센서는 베어링과 내·외륜 사이에 미세한 충돌이 발생할 때, 이를 공진 증폭 시켜 유의미한 검출신호를 출력시킨다. 본 연구에서는 저속 회전기계 모듈을 제작하여 가속도계로 신호 검출이 어려울 정도의 작은 결함을 만들었다. 이를 대상으로 쇽 펄스 센서로 미세한 결함 신호의 검출이 가능한지를 확인하였다. Large megawatt wind turbines produce electricity at very low speeds for long periods of time. The bearings used in the turbine are susceptible to failure due to prolonged exposure to cyclic loads. It is important to diagnose bearings defects early to prevent large failures in advance. However, when the rotation speed of the shaft is low and the load is small, it is not easy to detect a minute abnormal vibration from a small defect by a general accelerometer. When a slight collision occurs between the bearing and the inner/outer races, the shock pulse sensor is resonated and generates a defect signal. In this study, a low - speed rotating machine module was fabricated and made a small defect that is difficult to detect signal with accelerometer. With this module, we examined whether a shock pulse sensor can detect a minute defective signal.