Effects of Spark Plug Number and Location in Natural Gas Engines

1992 ◽  
Vol 114 (3) ◽  
pp. 475-479 ◽  
Author(s):  
R. C. Meyer ◽  
D. P. Meyers ◽  
S. R. King ◽  
W. E. Liss
Keyword(s):  
Natural Gas ◽  
Thermal Efficiency ◽  
Cylinder Pressure ◽  
Natural Gas Engines ◽  
Single Cylinder Engine ◽  
Spark Plug ◽  
Combustion Duration ◽  
Peak Cylinder Pressure ◽  
Wide Range ◽  
Pressure Peak

Combustion experiments were conducted on a spark-ignited single-cylinder engine operating on natural gas. A special open chamber cylinder head was designed to accept as many as four spark plugs. Data were obtained to investigate the effects of spark plug quantity and location on NOx, HC, CO emissions, brake and indicated thermal efficiency, MBT timing, combustion duration, ignition delay, peak cylinder pressure, peak cylinder temperature, and heat release over a wide range of equivalence ratios.

Comparative Analysis of EGR and Air Dilution in Spark-Ignited Natural Gas Engines

2017 ◽  
Author(s):  
William Glewen ◽  
Chris Hoops ◽  
Joel Hiltner ◽  
Michael Flory
Keyword(s):  
Natural Gas ◽  
Power Density ◽  
Thermal Efficiency ◽  
Gas Temperature ◽  
Natural Gas Engines ◽  
Cycle Simulation ◽  
Wide Range ◽  
Charge Mixture ◽  
The Impact ◽  
Three Way Catalyst

Industrial natural gas engines are used in a wide range of applications, each with unique requirements in terms of power density, initial cost, thermal efficiency, and other factors. As a result of these requirements, distinct engine designs have evolved to serve various applications. Heavy-duty spark-ignited engines can generally be divided into two broad categories based on their charge characteristics and method of emissions control. Stoichiometric engines are widely used in applications where first cost, absolute emissions and relative engine simplicity are more important than fuel consumption. In most of the developed world, stoichiometric engines are equipped with a three-way catalyst to control emissions of nitrogen oxides (NOx) as well as products of incomplete combustion and raw unburned fuel. Dilution of the charge mixture with excess air reduces the peak combustion gas temperature and associated heat rejection. As a result, lean burn engines are generally able to achieve higher efficiency and power density without inducing excessive component temperatures or end gas knock. NOx formation is mitigated by the reduced gas temperatures, such that most regulatory standards can currently be met in-cylinder. Significant obstacles exist to meeting more stringent future emissions regulations in this manner, however. Another possible strategy is to dilute the charge mixture with recirculated exhaust gas. This offers similar benefits as air dilution while maintaining the ability to use a three-way catalyst for emissions after-treatment. While similar principles apply in either case, the choice of diluent can have a significant impact on knock resistance, emissions formation, thermal efficiency, and other parameters of importance to engine developers and operators. This work aimed to examine the unique characteristics of EGR and air dilution from a thermodynamic and combustion perspective. A combination of cycle simulation tools and experimental data from a single-cylinder test engine was applied to demonstrate the impact of diluent properties on a fundamental level, and to illustrate departures from idealized behavior and practical considerations specific to the development of combustion systems for spark-ignited natural gas engines.

Evaluation of Spark Plug and Timing Configurations on the Fuel Consumption, Combustion Stability, and Emissions of a Large-Bore, Two-Stroke, Natural Gas Engine

2016 ◽  
Author(s):  
Derek Johnson ◽  
Marc Besch ◽  
Nathaniel Fowler ◽  
Robert Heltzel ◽  
April Covington
Keyword(s):  
Natural Gas ◽  
Fuel Consumption ◽  
Combustion Engine ◽  
Engine Performance ◽  
Combustion Stability ◽  
Oxides Of Nitrogen ◽  
Natural Gas Engines ◽  
Fuel Delivery ◽  
Spark Plug ◽  
Trade Offs

Emissions compliance is a driving factor for internal combustion engine research pertaining to both new and old technologies. New standards and compliance requirements for off-road spark ignited engines are currently under review and include greenhouse gases. To continue operation of legacy natural gas engines, research is required to increase or maintain engine efficiency, while reducing emissions of carbon monoxide, oxides of nitrogen, and volatile organic compounds such as formaldehyde. A variety of technologies can be found on legacy, large-bore natural gas engines that allow them to meet current emissions standards — these include exhaust after-treatment, advanced ignition technologies, and fuel delivery methods. The natural gas industry uses a variety of spark plugs and tuning methods to improve engine performance or decrease emissions of existing engines. The focus of this study was to examine the effects of various spark plug configurations along with spark timing to examine any potential benefits. Spark plugs with varied electrode diameter, number of ground electrodes, and heat ranges were evaluated against efficiency and exhaust emissions. Combustion analyses were also conducted to examine peak firing pressure, location of peak firing pressure, and indicated mean effective pressure. The test platform was an AJAX-E42 engine. The engine has a bore and stroke of 0.216 × 0.254 meters (m), respectively. The engine displacement was 9.29 liters (L) with a compression ratio of 6:1. The engine was modified to include electronic spark plug timing capabilities along with a mass flow controller to ensure accurate fuel delivery. Each spark plug configuration was examined at ignition timings of 17, 14, 11, 8, and 5 crank angle degrees before top dead center. The various configurations were examined to identify optimal conditions for each plug comparing trade-offs among brake specific fuel consumption, oxides of nitrogen, methane, formaldehyde, and combustion stability.

Comparative assessment of engine vibration, combustion, performance and emission characteristics between single and twin-cylinder diesel engines in unifuel and dual-fuel mode

2021 ◽  
pp. 1-39
Author(s):  
Akash Chandrabhan Chandekar ◽  
Sushmita Deka ◽  
Biplab K. Debnath ◽  
Ramesh Babu Pallekonda
Keyword(s):  
Natural Gas ◽  
Alternative Fuels ◽  
Load Condition ◽  
Alternative Fuel ◽  
Dual Fuel ◽  
Cylinder Pressure ◽  
Compressed Natural Gas ◽  
Single Cylinder ◽  
Engine Vibration ◽  
Single Cylinder Engine

Abstract The persistent efforts among the researchers are being done to reduce emissions by the exploration of different alternative fuels. The application of alternative fuel is also found to influence engine vibration. The present study explores the potential connection between the change of the engine operating parameters and the engine vibration pattern. The objective is to analyse the effect of alternative fuel on engine vibration and performance. The experiments are performed on two different engines of single cylinder and twin-cylinder variants at the load range of 0 to 34Nm, with steps of 6.8Nm and at the constant speed of 1500rpm. The single cylinder engine, fuelled with only diesel mode, is tested at two compression ratios of 16.5 and 17.5. While, the twin-cylinder engine with a constant compression ratio of 16.5, is tested at both diesel unifuel and diesel-compressed natural gas dual-fuel modes. Further, in dual-fuel mode, tests are conducted with compressed natural gas substitutions of 40%, 60% and 80% for given loads and speed. The engine vibration signatures are measured in terms of root mean square acceleration, representing the amplitude of vibration. The combustion parameters considered are cylinder pressure, rate of pressure rise, heat release rate and ignition delay. At higher loads, the vibration amplitude increases along with the cylinder pressure. The maximum peak cylinder pressure of 95bar is found in the case of the single cylinder engine at the highest load condition that also produced a peak vibration of 3219m/s2.

Advanced Gas Engine Cogeneration Technology for Special Applications

1995 ◽  
Vol 117 (4) ◽  
pp. 826-831 ◽  
Author(s):  
D. C. Plohberger ◽  
T. Fessl ◽  
F. Gruber ◽  
G. R. Herdin
Keyword(s):  
Natural Gas ◽  
Ambient Air ◽  
Pollutant Emissions ◽  
Thermal Reactor ◽  
Maximum Efficiency ◽  
Exhaust Aftertreatment ◽  
Natural Gas Engines ◽  
Low Emission ◽  
Wide Range ◽  
The U.S

In recent years gas Otto-cycle engines have become common for various applications in the field of power and heat generation. Gas engines in gen-sets and cogeneration plants can be found in industrial sites, oil and gas field application, hospitals, public communities, etc., mainly in the U.S., Japan, and Europe, and with an increasing potential in the upcoming areas in the far east. Gas engines are chosen sometimes even to replace diesel engines, because of their clean exhaust emission characteristics and the ample availability of natural gas in the world. The Austrian Jenbacher Energie Systeme AG has been producing gas engines in the range of 300 to 1600 kW since 1960. The product program covers state-of-the-art natural gas engines as well as advanced applications for a wide range of alternative gas fuels with emission levels comparable to Low Emission (LEV) and Ultra Low Emission Vehicle (ULEV) standards. In recent times the demand for special cogeneration applications is rising. For example, a turnkey cogeneration power plant for a total 14.4 MW electric power and heat output consisting of four JMS616-GSNLC/B spark-fired gas engines specially tuned for high altitude operation has been delivered to the well-known European ski resort of Sestriere. Sestriere is situated in the Italian Alps at an altitude of more than 2000 m (approx. 6700 ft) above sea level. The engines feature a turbocharging system tuned to an ambient air pressure of only 80 kPa to provide an output and efficiency of each 1.6 MW and up to 40 percent @ 1500 rpm, respectively. The ever-increasing demand for lower pollutant emissions in the U.S. and some European countries initiates developments in new exhaust aftertreatment technologies. Thermal reactor and Selective Catalytic Reduction (SCR) systems are used to reduce tailpipe CO and NOx emissions of engines. Both SCR and thermal reactor technology will shift the engine tuning to achieve maximum efficiency and power output. Development results are presented, featuring the ultra low emission potential of biogas and natural gas engines with exhaust aftertreatment.

Formaldehyde Formation in Large Bore Engines Part 2: Factors Affecting Measured CH2O

1999 ◽  
Vol 122 (4) ◽  
pp. 611-616 ◽  
Author(s):  
Daniel B. Olsen ◽  
Charles E. Mitchell
Keyword(s):  
Natural Gas ◽  
Air Pollutant ◽  
Operating Conditions ◽  
Factors Affecting ◽  
Natural Gas Engines ◽  
Spark Timing ◽  
Wide Range ◽  
Hazardous Air Pollutant ◽  
Relationship Of ◽  
The Impact

Current research shows that the only hazardous air pollutant of significance emitted from large bore natural gas engines is formaldehyde CH2O. A literature review on formaldehyde formation is presented focusing on the interpretation of published test data and its applicability to large bore natural gas engines. The relationship of formaldehyde emissions to that of other pollutants is described. Formaldehyde is seen to have a strong correlation to total hydrocarbon (THC) level in the exhaust. It is observed that the ratio of formaldehyde to THC concentration is roughly 1.0–2.5 percent for a very wide range of large bore engines and operating conditions. The impact of engine operating parameters, load, rpm, spark timing, and equivalence ratio, on formaldehyde emissions is also evaluated. [S0742-4795(00)01004-8]

Extending the Lean Limit of Natural Gas Engines

2008 ◽  
Author(s):  
R. L. Evans
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Lean Burn ◽  
Stratified Charge ◽  
Natural Gas Engines ◽  
Spark Plug ◽  
Charge Mixture ◽  
Cyclic Variations ◽  
Lean Limit ◽  
The Stability

Two different methods to improve the thermal efficiency and reduce the emissions from lean-burn natural gas fuelled engines have been developed, and are described in this paper. One method used a “squish-jet” combustion chamber designed specifically to enhance turbulence generation, while the second method provided a partially stratified-charge mixture near the spark plug in order to enhance the ignition of lean mixtures of natural gas and air. The squish-jet combustion chamber was found to reduce Bsfc by up to 4.8% in a Ricardo Hydra engine, while the NOx – efficiency tradeoff was greatly improved in a Cummins L-10 engine. The partially stratified-charge combustion system extended the lean limit of operation in the Ricardo Hydra by some 10%, resulting in a 64% reduction in NOx emissions at the lean limit of operation. Both techniques were also shown to be effective in increasing the stability of combustion, thereby reducing cyclic variations in cylinder pressure.

Estimation of cycle-resolved in-cylinder pressure and air-fuel ratio using spark plug ionization current sensing

2001 ◽  
Vol 2 (4) ◽  
pp. 263-276 ◽  
Author(s):  
B Lee ◽  
Y G Guezennec ◽  
G Rizzoni
Keyword(s):  
Real Time ◽  
Combustion Process ◽  
Pressure Sensors ◽  
Cylinder Pressure ◽  
Current Signal ◽  
Ionization Current ◽  
Fuel Ratio ◽  
Spark Plug ◽  
Wide Range ◽  
Combustion Diagnostics

In recent years, several new sensor technologies have been developed and implemented within automotive industries due to the increasing requirements for improved engine performance and emission reduction. It requires detailed and specified knowledge of the combustion process inside the engine cylinder along with a sophisticated technique in engine diagnostics and control. During the last few years, the ionization current signal detection has been the emerging technology in the new sensor developments, in which the spark plug is used as a combustion probe, to improve the performance and emissions of an automobile engine. In this paper, a novel methodology will be presented which allows the cycle-resolved as well as the mean-value estimation of the air-fuel ratio and in-cylinder pressure based on the ionization current signal measurements. The implementation details of this methodology as well as extensive results will be presented for a wide range of air-fuel ratios. The main advantage of this new approach to process the ionization signal is its strong potential for real-time estimation of the air-fuel ratio and combustion diagnostics of individual cylinders and engine cycles. All the complex physics during the actual events (combustion process, ion generation, engine dynamics, etc.) are automatically self-extracted by this technique from acquired data in an initial off-line mapping phase. Once this has been performed, the air-fuel ratio and in-cylinder pressure can easily be estimated for each individual cylinder and combustion event in real-time with few computational requirements. Hence, this methodology has a high potential for the real-time combustion diagnostics and engine control based on the air-fuel ratio and in-cylinder pressure, while eliminating the requirements for installing expensive air-fuel ratio and in-cylinder pressure sensors. The results indicate that estimation of the cycle-resolved air-fuel ratio and in-cylinder pressure is reasonably accurate and robust, despite the inherently noisy character of the ionization signals, with estimation errors typically in the order of 2 per cent or less, except for very fuel-rich conditions.

Experimental Study on Homogeneous Charge Compression Ignition Combustion With Fuel of Dimethyl Ether and Natural Gas

2005 ◽  
Vol 128 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Mingfa Yao ◽  
Zunqing Zheng ◽  
Jin Qin
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Dimethyl Ether ◽  
Flow Rate ◽  
Heat Release Rate ◽  
Release Rate ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Hcci Combustion ◽  
Peak Cylinder Pressure

The homogeneous charge compression ignition (HCCI) combustion fueled by dimethyl ether (DME) and compressed natural gas (CNG) was investigated. The experimental work was carried out on a single-cylinder diesel engine. The results show that adjusting the proportions of DME and CNG is an effective technique for controlling HCCI combustion and extending the HCCI operating range. The combustion process of HCCI with dual fuel is characterized by a distinctive two-stage heat release process. As CNG flow rate increases, the magnitude of peak cylinder pressure and the peak heat release rate in the second stage goes up. As DME flow rate increases, the peak cylinder pressure, heat release rate, and NOx emissions increase while THC and CO emissions decrease.

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

Open Physics ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document