Combustibles Versus Nitrogen Fixation in Gas Engine Operation and Lubrication

1965 ◽  
Vol 87 (2) ◽  
pp. 175-180
Author(s):  
R. G. Mastin
Keyword(s):  
Nitrogen Fixation ◽  
Lubricating Oil ◽  
Exhaust Gas ◽  
Gas Analyzer ◽  
Engine Operation ◽  
Gas Engine

Nitration is preferable to combustibles in the operation of the gas engine because it affects only the lubricating oil. Combustibles affect, in addition to lubricating oil, engine parts by the deposition of carbon, and cause expensive fuel waste. The data were gathered with the aid of an exhaust gas analyzer and a spectrophotometer.

Measurement of semi-volatiles in used natural gas engine oil using thermogravimetric analysis

2007 ◽  
Vol 8 (5) ◽  
pp. 439-448 ◽  
Author(s):  
G Mullins ◽  
J Truhan
Keyword(s):  
Thermogravimetric Analysis ◽  
Natural Gas ◽  
Combustion Engine ◽  
Inert Atmosphere ◽  
Engine Oil ◽  
Lubricating Oil ◽  
Engine Operation ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Constant Rate

Semi-volatile in internal combustion engine lubricating oil may be responsible for limiting service life and can lead to in-cylinder deposit formation. In order to measure semivolatile content, a new thermogravimetric analysis (TGA) procedure has been adapted from existing soot procedures to determine the levels of semi-volatile compounds in progressively aged lubricating oil samples from a natural gas engine dynamometer test cell run. The per cent weight remaining at 550 °C, while heated at a constant rate in an inert atmosphere, varied linearly with running time, viscosity, and oxidation and nitration. The method yielded reproducible run-to-run results and showed good agreement between helium and argon atmospheres. Mass spectroscopy data confirmed increased levels of high molecular weight species during engine operation. This method may be applicable to diesel engine oil samples.

Modeling the Performance of a Turbo-Charged Spark Ignition Natural Gas Engine With Cooled Exhaust Gas Recirculation

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Hailin Li ◽  
Ghazi A. Karim
Keyword(s):  
Natural Gas ◽  
Exhaust Gas Recirculation ◽  
Spark Ignition ◽  
Exhaust Gas ◽  
Engine Operation ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Auto Ignition ◽  
Wide Range ◽  
Gas Recirculation

A variety of gaseous fuels and a wide range of cooled exhaust gas recirculation (EGR) can be used in turbo-charged spark ignition (S.I.) gas engines. This makes the experimental investigation of the knocking behavior both unwieldy and uneconomical. Accordingly, it would be attractive to develop suitable effective predictive models that can be used to improve the understanding of the roles of various design and operating parameters and achieve a more optimized turbo-charged engine operation, particularly when EGR is employed. This paper presents the simulated performance of a turbo-charged S.I. natural gas engine when employing partially cooled EGR. A two-zone predictive model developed mainly for naturally aspirated S.I. engine applications of natural gas, described and validated earlier, was extended to consider applications employing turbo-chargers, intake charge after-coolers, and cooled EGR. A suitably detailed kinetic scheme involving 155 reaction steps and 39 species for the oxidation of natural gas is employed to examine the pre-ignition reactions of the unburned mixtures that can lead to knock prior to being fully consumed by the propagating flame. The model predicts the onset of knock and its intensity once end gas auto-ignition occurs. The effects of turbo-charging and cooled EGR on the total energy to be released through auto-ignition and its effect on the intensity of the resulting knock are considered. The consequences of changes in the effectiveness of after and EGR-coolers, lean operation and reductions in the compression ratio on engine performance parameters, especially the incidence of knock are examined. The benefits, limitations, and possible penalties of the application of fuel lean operation combined with cooled EGR are also examined and discussed.

scholarly journals A New Method to Determine the Impact of Individual Field Quantities on Cycle-to-Cycle Variations in a Spark-Ignited Gas Engine

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Kinetic Energy ◽  
Negative Impact ◽  
Operating Conditions ◽  
Engine Operation ◽  
Gas Engine ◽  
Cycle Simulation ◽  
Simulation Results ◽  
The Impact

Cycle-to-cycle variations (CCV) in spark-ignited (SI) engines impose performance limitations and in the extreme limit can lead to very strong, potentially damaging cycles. Thus, CCV force sub-optimal engine operating conditions. A deeper understanding of CCV is key to enabling control strategies, improving engine design and reducing the negative impact of CCV on engine operation. This paper presents a new simulation strategy which allows investigation of the impact of individual physical quantities (e.g., flow field or turbulence quantities) on CCV separately. As a first step, multi-cycle unsteady Reynolds-averaged Navier–Stokes (uRANS) computational fluid dynamics (CFD) simulations of a spark-ignited natural gas engine are performed. For each cycle, simulation results just prior to each spark timing are taken. Next, simulation results from different cycles are combined: one quantity, e.g., the flow field, is extracted from a snapshot of one given cycle, and all other quantities are taken from a snapshot from a different cycle. Such a combination yields a new snapshot. With the combined snapshot, the simulation is continued until the end of combustion. The results obtained with combined snapshots show that the velocity field seems to have the highest impact on CCV. Turbulence intensity, quantified by the turbulent kinetic energy and turbulent kinetic energy dissipation rate, has a similar value for all snapshots. Thus, their impact on CCV is small compared to the flow field. This novel methodology is very flexible and allows investigation of the sources of CCV which have been difficult to investigate in the past.

Stabilizing Excessive EGR With an Oxidation Catalyst on a Modern Diesel Engine

2002 ◽  
Author(s):  
Ming Zheng ◽  
David K. Irick ◽  
Jeffrey Hodgson
Keyword(s):  
Diesel Engine ◽  
Oxidation Catalyst ◽  
Stable Operation ◽  
Exhaust Gas ◽  
Oxides Of Nitrogen ◽  
Engine Operation ◽  
Turbocharged Diesel Engine ◽  
New Approach ◽  
Cyclic Variations ◽  
Gas Recirculation

For diesel engines (CIDI) the excessive use of exhaust gas recirculation (EGR) can reduce in-cylinder oxides of nitrogen (NOx) generation dramatically, but engine operation can also approach zones with high instabilities, usually accompanied with high cycle-to-cycle variations and deteriorated emissions of total hydrocarbon (THC), carbon monoxide (CO), and soot. A new approach has been proposed and tested to eliminate the influences of recycled combustibles on such instabilities, by applying an oxidation catalyst in the high-pressure EGR loop of a turbocharged diesel engine. The testing was directed to identifying the thresholds of stable operation at high rates of EGR without causing cycle-to-cycle variations associated with untreated recycled combustibles. The elimination of recycled combustibles using the oxidation catalyst showed significant influences on stabilizing the cyclic variations, so that the EGR applicable limits are effectively extended. The attainability of low NOx emissions with the catalytically oxidized EGR is also evaluated.

A Fast Exhaust-Gas Analyzer for the ITER Fusion Experiment Divertor

2010 ◽  
Vol 38 (3) ◽  
pp. 315-319 ◽  
Author(s):  
C.C. Klepper ◽  
E.P. Carlson ◽  
J.J. Moschella ◽  
R.C. Hazelton ◽  
M.D. Keitz ◽  
...  
Keyword(s):  
Exhaust Gas ◽  
Gas Analyzer

scholarly journals Thermodynamic cycles variability of TJI gas engine with different mixture preparation systems

2020 ◽  
Vol 181 (2) ◽  
pp. 46-52
Author(s):  
Filip SZWAJCA ◽  
Krzysztof WISŁOCKI
Keyword(s):  
Fuel Injection ◽  
Combustion Process ◽  
Engine Operation ◽  
Gas Engine ◽  
Part Load ◽  
Mixture Preparation ◽  
Key Factor ◽  
Test Engine ◽  
Operation Stability ◽  
The Impact

Gas engines are a viable source of propulsion due to the ecological indicators of gas fuels and the large amount of the needed natural resources. Combustion of lean homogeneous gas mixtures allows achieving higher thermal efficiency values, which is a key factor in current engine development trends. Using the spark-jet ignition system (also called as Turbulent Jet Ignition or Two-stage combustion) significantly improves the efficiency and stability of the combustion process, especially in the part-load operation on lean or very lean mixtures. This paper presents the impact of using two different fuel injection methods: Port Fuel Injection or Mixer on the operation stability of a gas engine designed for LDVs. Comparative studies of two different mixture preparation systems were carried out on a single-cylinder AVL 5804 test engine. By re-cording the cylinder pressure for a significant number of engine cycles, it became possible to determine the repeatability of engine operation and to correlate the results with the mixture formation system and the air-fuel ratio. In the performed research the beneficial effect of the mixer system application on the engine operation stability in the part-load conditions was found.

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