A study on premixed charge compression ignition combustion of natural gas with direct injection

2005 ◽  
Vol 6 (5) ◽  
pp. 443-451 ◽  
Author(s):  
T Ishiyama ◽  
H Kawanabe ◽  
K Ohashi ◽  
M Shioji ◽  
S Nakai
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Direct Injection ◽  
Pressure Rise ◽  
Combustion Efficiency ◽  
Compression Ignition ◽  
Load Range ◽  
Injection Angle ◽  
Nozzle Orifice ◽  
Rich Mixture

In order to extend the available load range and obtain higher thermal efficiency in natural gas premixed charge compression ignition (PCCI) engines, a strategy for controlling direct injection combustion is discussed. Experimental results from single-cylinder engine tests demonstrate the possibility to extend load range by direct fuel injection. Reduced nozzle orifice size and reduced injection angle provide higher combustion efficiency; however, this promotes the tendency to knock because of the formation of a locally rich mixture. Arising from discussions based on prediction by computational fluid dynamics (CFD) code, considering mixture heterogeneity, it is suggested that controlling probability density functions (PDFs) of fuel concentration could be a means to control the rate of pressure rise. Restricted air utilization is useful to activate combustion at low overall equivalence ratios; on the other hand, full utilization of in-cylinder air and formation of a quantity of lean mixture can provide mild combustion.

Combustion characteristics of natural-gas direct-injection combustion under various fuel injection timings

2003 ◽  
Vol 217 (5) ◽  
pp. 393-401 ◽  
Author(s):  
Z Huang ◽  
S Shiga ◽  
T Ueda ◽  
H Nakamura ◽  
T Ishima ◽  
...  
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Direct Injection ◽  
Pressure Rise ◽  
Combustion Efficiency ◽  
Time Interval ◽  
Injection Timing ◽  
Ignition Timing ◽  
Fuel Injection Timing ◽  
Wide Range

The characteristics of natural-gas direct-injection combustion under various fuel injection timings were studied by using a rapid compression machine. Results show that natural-gas direct injection can result in combustion that is much faster than homogeneous combustion while shortening the time interval between injection timing and ignition timing can markedly decrease the combustion duration. Unburned hydrocarbon would increase over a wide range of equivalence ratios, shortening the time interval between injection timing and ignition timing can decrease the value to that of homogeneous-mixture combustion. The NOx level is high but the CO level is low over a wide range of equivalence ratios and is little affected by fuel injection timing. High values of pressure rise due to combustion can be realized and it is insensitive to the variation in fuel injection timing. High combustion efficiency can be achieved, which is also independent of injection timing.

Numerical Studies of Glow Plug Shield on Natural Gas Ignition Characteristics in a CI Engine

2016 ◽  
Author(s):  
Kang Pan ◽  
James S. Wallace
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Numerical Study ◽  
Direct Injection ◽  
Fuel Mixture ◽  
Injection Angle ◽  
Glow Plug ◽  
Gas Ignition ◽  
Ignition And Combustion

This paper presents a numerical study on fuel injection, ignition and combustion in a direct-injection natural gas (DING) engine with ignition assisted by a shielded glow plug (GP). The shield geometry is investigated by employing different sizes of elliptical shield opening and changing the position of the shield opening. The results simulated by KIVA-3V indicated that fuel ignition and combustion is very sensitive to the relative angle between the fuel injection and the shield opening, and the use of an elliptical opening for the glow plug shield can reduce ignition delay by 0.1∼0.2ms for several specific combinations of the injection angle and shield opening size, compared to a circular shield opening. In addition, the numerical results also revealed that the natural gas ignition and flame propagation will be delayed by lowering a circular shield opening from the fuel jet center plane, due to the blocking effect of the shield to the fuel mixture, and hence it will reduce the DING performance by causing a longer ignition delay.

scholarly journals Influence of Charge Motion and Compression Ratio on the Performance of a Combustion Concept Employing In-Cylinder Gasoline and Natural Gas Blending

2017 ◽  
Author(s):  
James Sevik ◽  
Michael Pamminger ◽  
Thomas Wallner ◽  
Riccardo Scarcelli ◽  
Steven Wooldridge ◽  
...  
Keyword(s):  
Natural Gas ◽  
Carbon Dioxide Emissions ◽  
Fuel Injection ◽  
Direct Injection ◽  
Peak Load ◽  
Charge Motion ◽  
Load Range ◽  
Absolute Increase ◽  
Efficient Operation ◽  
Indicated Mean Effective Pressure

The present paper represents a small piece of an extensive experimental effort investigating the dual-fuel operation of a light-duty spark ignited engine. Natural gas (NG) was directly injected into the cylinder and gasoline was injected into the intake-port. Direct injection of NG was used in order to overcome the power density loss usually experienced with NG port-fuel injection as it allows an injection after intake valve closing. Having two separate fuel systems allows for a continuum of in-cylinder blend levels from pure gasoline to pure NG operation. The huge benefit of gasoline is its availability and energy density, whereas NG allows efficient operation at high load due to improved combustion phasing enabled by its higher knock resistance. Furthermore, using NG allowed a reduction of carbon dioxide emissions across the entire engine map due to the higher hydrogen-to-carbon ratio. Exhaust gas recirculation (EGR) was used to (a) increase efficiency at low and part-load operation and (b) reduce the propensity of knock at higher compression ratios (CR) thereby enabling blend levels with greater amount of gasoline across a wider operating range. Two integral engine parameters, CR and in-cylinder turbulence levels, were varied in order to study their influence on efficiency, emissions and performance over a specific speed and load range. Increasing the CR from 10.5 to 14.5 allowed an absolute increase in indicated thermal efficiency of more than 3% for 75% NG (25% gasoline) operation at 8 bar net indicated mean effective pressure and 2500 RPM. However, as anticipated, the achievable peak load at CR 14.5 with 100% gasoline was greatly reduced due to its lower knock resistance. The in-cylinder turbulence level was varied by means of tumble plates as well as an insert for the NG injector that guides the injection “spray” to augment the tumble motion. The usage of tumble plates showed a significant increase in EGR dilution tolerance for pure gasoline operation, however, no such impact was found for blended operation of gasoline and NG.

scholarly journals Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation

2015 ◽  
Author(s):  
Reed Hanson ◽  
Andrew Ickes ◽  
Thomas Wallner
Keyword(s):  
Natural Gas ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Direct Injection ◽  
Peak Load ◽  
Combustion Process ◽  
Pressure Rise ◽  
Dual Fuel ◽  
The Impact ◽  
Injection Strategies

Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection of a higher reactivity fuel, otherwise known as Reactivity Controlled Compression Ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13L multi-cylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and direct injection of diesel fuel. Engine testing was conducted at an engine speed of 1200 RPM over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study. The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection quantity was reduced to keep peak cylinder pressure and maximum pressure rise rate under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar BMEP with a peak brake thermal efficiency of 47.6%.

scholarly journals Optimization of gasoline compression ignition combustion with ozone addition and two-stage direct-injection at middle loads

2021 ◽  
pp. 146808742098457
Author(s):  
Yoshimitsu Kobashi ◽  
Tu Dan Dan Da ◽  
Ryuya Inagaki ◽  
Gen Shibata ◽  
Hideyuki Ogawa
Keyword(s):  
Ozone Concentration ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Direct Injection ◽  
Pressure Rise ◽  
Maximum Pressure ◽  
Injection Timing ◽  
Compression Ignition ◽  
Ozone Addition ◽  
Primary Reference

Ozone (O3) was introduced into the intake air to control the ignition in a gasoline compression ignition (GCI) engine. An early fuel injection at −68 °CA ATDC was adopted to mix the fuel with the reactive O-radicals decomposed from the O3, before the reduction of the O-radicals due to their recombination would take place. The second injection was implemented near top dead center to optimize the profile of the heat release rate. The engine experiments were performed around the indicated mean effective pressure (IMEP) of 0.67 MPa with a primary reference fuel, octane number 90 (PRF90), maintaining the 15% intake oxygen concentration with the EGR. The quantity of the first injection, the second injection timing as well as the ozone concentration were changed as experimental parameters. The results showed that the GCI operation with the ozone addition makes it possible to reduce the maximum pressure rise rate while attaining high thermal efficiency, compared to that without the ozone. Appropriate combinations of the ozone concentration and the first injection quantity achieve low smoke and NOx emissions. Further, the ozone-assisted GCI operation was compared with conventional diesel operation. The results showed that the indicated thermal efficiency of the ozone-assisted GCI combustion is slightly lower than that of the conventional diesel combustion, but that GCI assisted with ozone is highly advantageous to the smoke and NOx emissions.

scholarly journals Influence of Charge Motion and Compression Ratio on the Performance of a Combustion Concept Employing In-Cylinder Gasoline and Natural Gas Blending

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
James Sevik ◽  
Michael Pamminger ◽  
Thomas Wallner ◽  
Riccardo Scarcelli ◽  
Steven Wooldridge ◽  
...  
Keyword(s):  
Natural Gas ◽  
Carbon Dioxide Emissions ◽  
Fuel Injection ◽  
Direct Injection ◽  
Peak Load ◽  
Charge Motion ◽  
Load Range ◽  
Absolute Increase ◽  
Efficient Operation ◽  
Indicated Mean Effective Pressure

The present paper represents a small piece of an extensive experimental effort investigating the dual-fuel operation of a light-duty spark ignited engine. Natural gas (NG) was directly injected into the cylinder and gasoline was injected into the intake-port. Direct injection (DI) of NG was used in order to overcome the power density loss usually experienced with NG port-fuel injection (PFI) as it allows an injection after intake valve closing. Having two separate fuel systems allows for a continuum of in-cylinder blend levels from pure gasoline to pure NG operation. The huge benefit of gasoline is its availability and energy density, whereas NG allows efficient operation at high load due to improved combustion phasing enabled by its higher knock resistance. Furthermore, using NG allowed a reduction of carbon dioxide emissions across the entire engine map due to the higher hydrogen-to-carbon ratio. Exhaust gas recirculation (EGR) was used to (a) increase efficiency at low and part-load operation and (b) reduce the propensity of knock at higher compression ratios (CRs) thereby enabling blend levels with greater amount of gasoline across a wider operating range. Two integral engine parameters, CR and in-cylinder turbulence levels, were varied in order to study their influence on efficiency, emissions, and performance over a specific speed and load range. Increasing the CR from 10.5 to 14.5 allowed an absolute increase in indicated thermal efficiency of more than 3% for 75% NG (25% gasoline) operation at 8 bar net indicated mean effective pressure (IMEP) and 2500 rpm. However, as anticipated, the achievable peak load at CR 14.5 with 100% gasoline was greatly reduced due to its lower knock resistance. The in-cylinder turbulence level was varied by means of tumble plates (TPs) as well as an insert for the NG injector that guides the injection “spray” to augment the tumble motion. The usage of TPs showed a significant increase in EGR dilution tolerance for pure gasoline operation, however, no such impact was found for blended operation of gasoline and NG.

Comparison between gasoline direct injection and compressed natural gas port fuel injection under maximum load condition

Energy ◽  
2020 ◽  
Vol 197 ◽  
pp. 117173 ◽  
Author(s):  
Jeongwoo Lee ◽  
Cheolwoong Park ◽  
Jongwon Bae ◽  
Yongrae Kim ◽  
Sunyoup Lee ◽  
...  
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Direct Injection ◽  
Load Condition ◽  
Maximum Load ◽  
Gasoline Direct Injection ◽  
Compressed Natural Gas ◽  
Port Fuel Injection

Study of High Load Operation Limit Expansion for Gasoline Compression Ignition Engines

2006 ◽  
Vol 128 (2) ◽  
pp. 377-387 ◽  
Author(s):  
Koudai Yoshizawa ◽  
Atsushi Teraji ◽  
Hiroshi Miyakubo ◽  
Koichi Yamaguchi ◽  
Tomonori Urushihara
Keyword(s):  
Fuel Injection ◽  
Control Method ◽  
Combustion Process ◽  
High Load ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Timing Control ◽  
Load Range ◽  
Compression Ignition Engines ◽  
Spark Plug

In this research, combustion characteristics of gasoline compression ignition engines have been analyzed numerically and experimentally with the aim of expanding the high load operation limit. The mechanism limiting high load operation under homogeneous charge compression ignition (HCCI) combustion was clarified. It was confirmed that retarding the combustion timing from top dead center (TDC) is an effective way to prevent knocking. However, with retarded combustion, combustion timing is substantially influenced by cycle-to-cycle variation of in-cylinder conditions. Therefore, an ignition timing control method is required to achieve stable retarded combustion. Using numerical analysis, it was found that ignition timing control could be achieved by creating a fuel-rich zone at the center of the cylinder. The fuel-rich zone works as an ignition source to ignite the surrounding fuel-lean zone. In this way, combustion consists of two separate auto-ignitions and is thus called two-step combustion. In the simulation, the high load operation limit was expanded using two-step combustion. An engine system identical to a direct-injection gasoline (DIG) engine was then used to validate two-step combustion experimentally. An air-fuel distribution was created by splitting fuel injection into first and second injections. The spark plug was used to ignite the first combustion. This combustion process might better be called spark-ignited compression ignition combustion (SI-CI combustion). Using the spark plug, stable two-step combustion was achieved, thereby validating a means of expanding the operation limit of gasoline compression ignition engines toward a higher load range.

scholarly journals Impact of injection strategies on combustion characteristics, efficiency and emissions of gasoline compression ignition operation in a heavy-duty multi-cylinder engine

2018 ◽  
Vol 21 (8) ◽  
pp. 1426-1440 ◽  
Author(s):  
Buyu Wang ◽  
Michael Pamminger ◽  
Ryan Vojtech ◽  
Thomas Wallner
Keyword(s):  
High Temperature ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Pressure Rise ◽  
Pilot Injection ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Temperature Combustion ◽  
Gas Recirculation ◽  
Direct Fuel Injection

Gasoline compression ignition using a single gasoline-type fuel for direct/port injection has been shown as a method to achieve low-temperature combustion with low engine-out NOx and soot emissions and high indicated thermal efficiency. However, key technical barriers to achieving low-temperature combustion on multi-cylinder engines include the air handling system (limited amount of exhaust gas recirculation) as well as mechanical engine limitations (e.g. peak pressure rise rate). In light of these limitations, high-temperature combustion with reduced amounts of exhaust gas recirculation appears more practical. Furthermore, for high-temperature gasoline compression ignition, an effective aftertreatment system allows high thermal efficiency with low tailpipe-out emissions. In this work, experimental testing was conducted on a 12.4 L multi-cylinder heavy-duty diesel engine operating with high-temperature gasoline compression ignition combustion with port and direct injection. Engine testing was conducted at an engine speed of 1038 r/min and brake mean effective pressure of 1.4 MPa for three injection strategies, late pilot injection, early pilot injection, and port/direct fuel injection. The impact on engine performance and emissions with respect to varying the combustion phasing were quantified within this study. At the same combustion phasing, early pilot injection and port/direct fuel injection had an earlier start of combustion and higher maximum pressure rise rates than late pilot injection attributable to more premixed fuel from pilot or port injection; however, brake thermal efficiencies were higher with late pilot injection due to reduced heat transfer. Early pilot injection also exhibited the highest cylinder-to-cylinder variations due to differences in injector behavior as well as the spray/wall interactions affecting mixing and evaporation process. Overall, peak brake thermal efficiency of 46.1% and 46% for late pilot injection and port/direct fuel injection was achieved comparable to diesel baseline (45.9%), while early pilot injection showed the lowest brake thermal efficiency (45.3%).

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