Optical Diagnostics for Knock in Compression-Ignition Engines via High-Speed Imaging

2018 ◽  
Vol 11 (6) ◽  
pp. 903-918 ◽  
Author(s):  
Ming Zhao ◽  
Sebastian Kaiser
Keyword(s):  
High Speed ◽  
Optical Diagnostics ◽  
Compression Ignition ◽  
High Speed Imaging ◽  
Compression Ignition Engines

An Imaging Study of Compression Ignition Phenomena of Iso-Octane, Indolene, and Gasoline Fuels in a Single-Cylinder Research Engine

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Bradley T. Zigler ◽  
Stephen M. Walton ◽  
Dimitris Assanis ◽  
Elizabeth Perez ◽  
Margaret S. Wooldridge ◽  
...  
Keyword(s):  
Heat Release ◽  
High Speed ◽  
Blue Emission ◽  
Primary Objective ◽  
Valuable Insight ◽  
Compression Ignition ◽  
Imaging Data ◽  
High Speed Imaging ◽  
Single Cylinder ◽  
Hcci Combustion

High-speed imaging combined with the optical access provided by a research engine offer the ability to directly image and compare ignition and combustion phenomena of various fuels. Such data provide valuable insight into the physical and chemical mechanisms important in each system. In this study, crank-angle resolved imaging data were used to investigate homogeneous charge compression ignition (HCCI) operation of a single-cylinder four-valve optical engine fueled using gasoline, indolene, and iso-octane. Lean operating limits were the focus of the study with the primary objective of identifying different modes of reaction front initiation and propagation for each fuel. HCCI combustion was initiated and maintained over a range of lean conditions for various fuels, from ϕ=0.69 to 0.27. The time-resolved imaging and pressure data show that high rates of heat release in HCCI combustion correlate temporally to simultaneous, intense volumetric blue emission. Lower rates of heat release are characteristic of spatially resolved blue emission. Gasoline supported leaner HCCI operation than indolene. Iso-octane showed a dramatic transition into misfire. Similar regions of preferential ignition were identified for each of the fuels considered using the imaging data.

Autoignition characteristics of diesel spray under different injection pressures and cold start strategy for compression ignition engines

2020 ◽  
pp. 146808742093460
Author(s):  
Ziming Yang ◽  
Fushui Liu ◽  
Yikai Li
Keyword(s):  
High Speed ◽  
Injection Pressure ◽  
Cold Start ◽  
Diesel Spray ◽  
High Speed Photography ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Application Range ◽  
Compression Ignition Engines ◽  
Injection Pressures

Poor cold start performance is one of the main factors restricting the application range of compression ignition engines. Stable flame generation in the cylinder is the prerequisite for the successful start of the engine. In order to explore ways to improve the cold start ability of the compression ignition engine, the ignition characteristics of diesel sprays at different injection pressures were studied in a constant volume combustion chamber. A high-speed photography technique was used to obtain the color images of the initial flames of diesel free sprays. And the yellow flame is introduced as the criterion for a successful flame generation. It was found that under moderate injection pressures, the reactant concentration and energy dissipation rate reached equilibrium. Under this condition, the duration of the blue flame is relatively stable, and it is most conducive to the generation of the yellow flame in the cylinder. The negative temperature coefficient phenomenon is also observed, and the temperature range in which this phenomenon occurs is identical with the change of injection pressure. A cold start strategy for the compression ignition engine is proposed by controlling the compression-end temperature in the cylinder to be higher than the threshold ignition temperature of diesel spray.

The Admiralty Cathode Ray Oscillograph Engine Indicator

1940 ◽  
Vol 143 (1) ◽  
pp. 39-47 ◽  
Author(s):  
F. D. Smith ◽  
E. H. Lakey ◽  
H. Morgan
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Magnetic Circuit ◽  
Narrow Band ◽  
Pressure Gauge ◽  
Compression Ignition ◽  
High Frequency Current ◽  
Compression Ignition Engines ◽  
Pressure Sensitive ◽  
Frequency Current

The Admiralty cathode ray oscillograph indicator was developed for use on compression-ignition engines of medium- and high-speed types. The size of the engine has not necessitated the development of the smallest possible unit. It consists of a pressure-sensitive device based on the magnetophone principle. The pressure to be recorded deflects a steel diaphragm and changes an air gap in a magnetic circuit. The magnet is energized by a high-frequency (20,000 cycles per sec.) alternating current flowing in an encircling coil. The pressure on the diaphragm modulates the high-frequency current, and the modulations are observed on the screen of a cathode ray oscillograph. The advantages of a high-frequency current in this connexion are: (1) all frequencies below about 2,000 cycles per sec. are faithfully reproduced; (2) steady pressures are recorded and calibration is effected with an ordinary pressure gauge; (3) amplifier and circuits have to transmit only a comparatively narrow band of frequencies. A disadvantage is that the upper limit of frequency (2,000 cycles per sec.) is not sufficiently high for the study of very rapid variations. The precautions necessary to ensure accuracy are discussed, and some examples of typical records obtained with the instrument are reproduced.

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