Investigation on the combustion noise of a pilot-ignited direct-injection natural-gas engine

In this paper, the effects of the injection timing, the injection pressure and the engine load on the combustion noise of a pilot-ignited direct-injection natural-gas engine were explored by analysing the separate components of the in-cylinder pressure. The results suggested that retarding the injection timing and reducing the injection pressure are effective ways of controlling the combustion noise. This can be attributed to the promoted burning rate at advanced injection timings and to the increased injection pressure. However, the effect of the engine load seems to be less obvious, although the resonance pressure level appears to increase with increasing engine load; the estimated combustion noise shows a decreasing tendency.

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Micro-pilot-induced Ignition Diesel/ Natural Gas Engine Control System Development and Engine Performance /Emission Optimization

10.24868/issn.2631-8741.2018.010 ◽

2018 ◽

Author(s):

G Zhao

Keyword(s):

Control System ◽

Natural Gas ◽

Gas Injection ◽

Injection Pressure ◽

Dual Fuel ◽

Injection Timing ◽

Gas Engine ◽

Natural Gas Engine ◽

Driving Circuit ◽

Injection Ratio

Diesel/natural gas dual fuel engine is acquiring more and more attention due to its potential to reduce NOX and soot emission simultaneously. Micro-pilot-induced diesel ignition natural gas engine is a popular manner to further improve the emission reduction capability of dual fuel engine. A six cylinder, four stroke, commonrail diesel engine is converted into dual fuel engine. Natural gas is injected into the intake manifold after the throttle. Five gas injection valves are used to control natural gas flow rate. Based to the established fuel supply system, a dual fuel control system is developed by using MS9S12XEP100 MCU. Voltage boosting circuit, fuel injector driving circuit, gas injection valve driving circuit and MeUn driving circuit are integrated on the platform of MCU hardware. Two ECU is connected to each other by CAN bus and several I/O ports to fulfil the fuel injection functional requirement. A software framework involves gas injection timing synchronization, fuel mode managing, multi-time injection. A MAP based fresh air mass flow rate and intake charge efficiency model is integrated in the MCU to calculate the fresh air quality in cylinder. The last part is performance optimization research at low load. Ignition diesel is divided into two stages, and the first injection timing, first injection ratio and injection pressure are used as controllable parameter to reduce NOX and HC emission. Experimental result reveal that by dividing ignition injection into two stage and advancing first injection to 60°CA BTDC CH4 emission can be reduced by 77% while NOX remains unchanged. Increasing the first injection ratio and injection pressure can also reduce THC emission. If injection pressure is higher than 75MPa, the effect of HC reduction effect is not that obvious. Experimental results shows that developed control system can accomplish the functional requirements of dual fuel engine management. Emission test results demonstrate that IMO TierII can be satisfied at diesel mode. DF mode emission performance can meet the requirement of IMO TierIII. Furthermore, as the first domestic product dual fuel dedicated control system, which has passed through the CCS authentication in China, the engine emission level can meet the current and upcoming China’s emission standard on non-road engine on the premise of guaranteeing engine power and economy.

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Effect of Injection Parameters and Strategy on the Noise From a Single Cylinder Direct Injection Diesel Engine

ASME 2011 Internal Combustion Engine Division Fall Technical Conference ◽

10.1115/icef2011-60148 ◽

2011 ◽

Author(s):

Sukhbir Singh Khaira ◽

Amandeep Singh ◽

Marcis Jansons

Keyword(s):

Diesel Engine ◽

Direct Injection ◽

Injection Pressure ◽

Combustion Noise ◽

Injection Timing ◽

Cylinder Pressure ◽

Frequency Spectra ◽

Single Cylinder ◽

Direct Injection Diesel Engine ◽

Injection Parameters

Acoustic noise emitted by a diesel engine generally exceeds that produced by its spark-ignited equivalent and may hinder the acceptance of this more efficient engine type in the passenger car market (1). This work characterizes the combustion noise from a single-cylinder direct-injection diesel engine and examines the degree to which it may be minimized by optimal choice of injection parameters. The relative contribution of motoring, combustion and resonance components to overall engine noise are determined by decomposition of in-cylinder pressure traces over a range of load, injection pressure and start of injection. The frequency spectra of microphone signals recorded external to the engine are correlated with those of in-cylinder pressure traces. Short Time Fourier Transformation (STFT) is applied to cylinder pressure traces to reveal the occurrence of motoring, combustion noise and resonance in the frequency domain over the course of the engine cycle. Loudness is found to increase with enhanced resonance, in proportion to the rate of cylinder pressure rise and under conditions of high injection pressure, load and advanced injection timing.

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Knocking characteristics of a high pressure direct injection natural gas engine operating in stratified combustion mode

Open Physics ◽

10.1515/phys-2021-0064 ◽

2021 ◽

Vol 19 (1) ◽

pp. 534-538

Author(s):

Qiang Zhang ◽

Yubo Yang ◽

Demin Jia ◽

Menghan Li

Keyword(s):

Natural Gas ◽

Direct Injection ◽

Cylinder Pressure ◽

Combustion Mode ◽

Pressure Oscillations ◽

Gas Engine ◽

Natural Gas Engines ◽

Natural Gas Engine ◽

Combustion Modes ◽

Stratified Combustion

Abstract Knocking becomes an increasingly important issue in direct injection natural gas engines with the application of new combustion modes. In this article, the knocking characteristics of natural gas engine operating in stratified combustion mode were studied with the aid of cylinder pressure oscillations and combustion parameters. The results indicated that knocking tendency will be stronger when operating in stratified combustion mode. The first to the fourth circumferential modes and the first radial mode are the featured modes for knocking behavior, while knocking is more serious when the duration of 10–50% of total energy released is shorter.

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Numerical analysis of the influence of the fuel injection timing and ignition position in a direct-injection natural gas engine

Energy Conversion and Management ◽

10.1016/j.enconman.2017.03.004 ◽

2017 ◽

Vol 149 ◽

pp. 748-759 ◽

Cited By ~ 28

Author(s):

Tao Wang ◽

Xin Zhang ◽

Jibao Zhang ◽

Xiaosen Hou

Keyword(s):

Numerical Analysis ◽

Natural Gas ◽

Fuel Injection ◽

Direct Injection ◽

Injection Timing ◽

Gas Engine ◽

Natural Gas Engine ◽

Fuel Injection Timing

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Numerical Simulations of Natural Gas Injection Pressure Effects on a Direct Injected, Pilot Ignited, Natural Gas Engine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.510.179 ◽

2014 ◽

Vol 510 ◽

pp. 179-184 ◽

Cited By ~ 1

Author(s):

Ying Gao ◽

Xiao Xiao Li ◽

Jun Li ◽

Lei Zhang ◽

Shu Hua Li

Keyword(s):

Natural Gas ◽

Direct Injection ◽

Gas Injection ◽

Combustion Process ◽

Injection Pressure ◽

Pressure Effects ◽

Compression Ignition Engine ◽

Gas Engine ◽

Natural Gas Engine ◽

Hc Emissions

Pilot-ignited direct injection of natural gas fueling of a compression ignition engine has been shown to keep high thermal efficiency as diesel engines. To further investigate the combustion process, the effect of natural gas injection pressure on combustion in a diesel engine fueled with pilot-ignited directly-injected natural gas was studied by multidimensional simulations while engine speed and other injection parameters were held constant. NO emissions are increased by higher gas injection pressure without significantly affecting cylinder pressure. By increasing gas injection pressure, HC emissions are reduced with the increase of cylinder temperature. The data got contributes to the development of the pilot-ignited high pressure direct injection natural gas engine.

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