Spark Ignition and Pre-Chamber Turbulent Jet Ignition Combustion Visualization

Abstract

Natural gas is a promising alternative fuel as it is affordable, available worldwide, has high knock resistance and low carbon content. This study focuses on the combustion visualization of spark ignition combustion in an optical single cylinder engine using natural gas at several air to fuel ratios and speed-load operating points. In addition, Turbulent Jet Ignition optical images are compared to the baseline spark ignition images at the world-wide mapping point (1500 rev/min, 3.3 bar IMEPn) in order to provide insight into the relatively unknown phenomenon of Turbulent Jet Ignition combustion. Turbulent Jet Ignition is an advanced spark initiated pre-chamber combustion system for otherwise standard spark ignition engines found in current passenger vehicles. This next generation pre-chamber design simply replaces the spark plug in a conventional spark ignition engine. Turbulent Jet Ignition enables very fast burn rates due to the ignition system producing multiple, widely distributed ignition sites, which consume the main charge rapidly. This high energy ignition results from the partially combusted (reacting) pre-chamber products initiating combustion in the main chamber. The distributed ignition sites enable relatively small flame travel distances enabling short combustion durations and high burn rates. Multiple benefits include extending the knock limit and initiating combustion in very dilute mixtures (excess air and/or EGR), with dilution levels being comparable to other low temperature combustion technologies (HCCI), without the complex control drawbacks.

Simulation of Hot-Jet Ignition in a Heated Constant-Volume Combustor Using Adadptive Mesh Refinement and Multi-Zone Reaction

“…Hot -jet ignition of premixed combustible mixture finds application in internal combustion engines [1][2]1, pulsed detonation engines [3] and wave rotor combustors [4][5][6][7][8]. This work is motivated by the potential of hotjet ignition of a combustible mixture as an enabling feature of pressure-gain combustion in gas turbine engines, particularly for the wave-rotor constant-volume combustor.…”

Traversing Hot-Jet Ignition in a Constant-Volume Combustor

“…This allows reliable combustion over a broader range of air-fuel ratios, shorter flame travel distances, and more rapid combustion in otherwise slow-burning lean mixtures. Chemically reactive radicals (e.g., H and OH) and jet-induced turbulence are estimated as equivalent to two orders of magnitude higher energy than spark ignition [2]. Tarzhanov et al [13] investigated using hot detonation products to detonate stagnant propane-air mixtures and found that detonation initiation depends on the initial volume concentrations, mass fraction of hot detonation products, and the energy deposited from the detonation products.…”

“…Hot-jet ignition of premixed combustible mixtures finds application in internal combustion engines [1,2], pulsed detonation engines [3], and wave rotor combustors [4][5][6]. Chemically active radicals and fast turbulent mixing in the jets create an explosion that is more energetic than a spark [3], allowing rapid ignition of lean mixtures.…”

Optical study of the use of recirculated gases for adiabatization of combustion process in the SIDI engine

“…With the present technical investigation possibilities, this task might be newly restarted. In recent years as such it can be also considered the Turbulent Jet Ignition (TJI), which makes it possible to increase the thermal efficiency of the system up to about 45% [17,18]. An actual research question should be the recognition of the impact of those prototype combustion systems, which can significantly reduce the emissions.…”