Optimization of Natural Gas Combustion in Spark-Ignited Engines Through Manipulation of Intake-Flow Configuration

Puzinauskas, Paulius V.; Willson, Bryan; Evans, K

doi:10.4271/2000-01-1948

Cited by 8 publications

(8 citation statements)

References 19 publications

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“…Mixing of air and natural gas may be a problem when using port injection [1]. Injection timing is selected to be centered around top dead center (TDC) gas-exchange at low to medium injection durations, and early enough to finish injection 30 degrees before inlet valve closing (IVC at 230 degrees after top dead center, ATDC) for long injection durations.…”

Section: Fuel Injection Timingmentioning

confidence: 99%

Lean Burn Natural Gas Operation vs. Stoichiometric Operation with EGR and a Three Way Catalyst

Einewall¹,

Tunestål²,

Johansson³

2005

SAE Technical Paper Series

104

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Exhaust Emissions from lean burn natural gas engines may not always be as low as the potential permits, especially engines with open loop lambda control. These engines can produce much higher emissions than a comparable diesel engine without exhaust gas after treatment. Even if the engine has closed loop lambda control, emissions are often unacceptably high for future emission regulations. A three way catalyst is, today, the best way to reduce hazardous emissions. The drawback is that the engine has to operate with a stoichiometric mixture and this leads to; higher heat losses, higher pumping work at low to medium loads, higher thermal stress on the engine and higher knock tendency (requiring lower compression ratio, and thus lower brake efficiency). One way to reduce these drawbacks is to dilute the stoichiometric mixture with EGR. This paper compares lean burn operation with operation at stoichiometric conditions diluted with EGR, and using a three way catalyst. The results show that nitric oxides (NO X) and hydrocarbon (HC) emissions are several orders of magnitude lower than at lean operation. Higher loads can be achieved, and brake efficiency is higher than lean operation optimized for low NO X production. A fast burning (high turbulence) combustion chamber is used to allow high amounts of dilution.

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Section: Fuel Injection Timingmentioning

confidence: 99%

Lean Burn Natural Gas Operation vs. Stoichiometric Operation with EGR and a Three Way Catalyst

Einewall¹,

Tunestål²,

Johansson³

2005

SAE Technical Paper Series

104

View full text Add to dashboard Cite

show abstract

“…On a four cylinder spark ignition natural gas engine with a multipoint fuel injection system and a single point fuel injection system, Puzinauskas et al (2000) found that the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) in the case of multipoint fuel injection is higher than that of the well mixed single point case at various air fuel ratio conditions. However, with the increase of engine speed and load, the COV of the IMEP sharply decreases in the former case, and the influence of the two fuel injection systems on the COV of the IMEP decreases.…”

Section: Introductionmentioning

confidence: 96%

Combustion and emission characteristics of a lean burn natural gas engine

Cho

2008

Int.J Automot. Technol.

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Lean burn is an effective way to improve spark ignition engine fuel economy. In this paper, the combustion and emission characteristics of a lean burn natural gas fuelled spark ignition engine were investigated at various throttle positions, fuel injection timings, spark timings and air fuel ratios. The results show that ignition timings, the combustion duration, the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) and engine-out emissions are dependent on the overall air fuel ratio, spark timings, throttle positions and fuel injection timings. With the increase of the air fuel ratio, the ignition delays and combustion duration increases. Fuel injection timings affect ignition timings, combustion duration, IMEP, and the COV of the IMEP. Late fuel injection timings can decrease the COV of the IMEP. Moreover, the change in the fuel injection timings reduces the engine-out CO, total hydrocarbon (THC) emissions. Lean burn can significantly reduce NOx emissions, but it results in high cyclic variations.

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“…Hence, a 25% throttle was chosen to investigate the impact of low throttle response on engine combustion performance in this study. Few studies have been published on the effects of injection timing on the charge preparation dynamics and the combustion process in CNG engines 26–28 . This research investigates the impact of injection timing on engine performance and combustion behaviour for gasoline and CNG engine at 25% throttle and 1700 engine speed.…”

Section: Introductionmentioning

confidence: 99%

Effect of injection timing on combustion and IMEP variation of a bi‐fuel compressed natural gas SI engine

Sahoo

Srivastava

2021

Env Prog and Sustain Energy

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Compressed natural gas (CNG) is a gaseous fuel stored under high pressure in a cylindrical tank. When the CNG is injected into the intake manifold, it expands in the manifold and displaces the air which reduces the volumetric efficiency of the engine. Thus, the corresponding overall energy inside the combustion chamber is also reduced, resulting in reduced power output. CNG injection timing with respect to intake valve opening and closing can be optimized to minimize the losses in volumetric efficiency loss and hence, the power output of the engine. In this study, the combustion instability of the CNG fueled engine has been studied under low throttle condition and compared with gasoline. A comparative investigation of the effects of the start of injection (SOI) timing on combustion stability was conducted on a single‐cylinder spark‐ignition (SI) engine fuelled with gasoline and CNG at 25% throttle opening condition. The ignition timing was kept fixed at 35°, and 40° CA bTDC for gasoline and CNG, respectively, and the SOI timing was varied from 240° CA bTDC to 100° CA aTDC of the intake stroke. The results indicated that SOI timing significantly affects in‐cylinder air‐fuel mixture formation and combustion stability for gasoline and CNG engine. SOI timing corresponds to the closed valve period, shows the higher fluctuation in combustion for gasoline compared to CNG. CNG shows lower fluctuation throughout SOI timing due to homogeneous air‐fuel mixture formation. Early SOI timing forms fuel stratification in the intake port and forms a rich air‐fuel mixture, which reduces the net power output of the CNG engine. CNG requires optimum SOI timing for improved combustion compared to gasoline. It reduced the combustion instability and fluctuation in indicated mean effective pressure. The results will benefit the development of a closed‐loop engine control system for a CNG system.

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Optimization of Natural Gas Combustion in Spark-Ignited Engines Through Manipulation of Intake-Flow Configuration

Cited by 8 publications

References 19 publications

Lean Burn Natural Gas Operation vs. Stoichiometric Operation with EGR and a Three Way Catalyst

Lean Burn Natural Gas Operation vs. Stoichiometric Operation with EGR and a Three Way Catalyst

Combustion and emission characteristics of a lean burn natural gas engine

Effect of injection timing on combustion and IMEP variation of a bi‐fuel compressed natural gas SI engine

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