Liquefied Petroleum Gas Injection Research Articles

Stratified liquefied petroleum gas—dimethyl ether compression ignition engine combustion at various intake valve open timings

The combustion and exhaust emissions characteristics of compression ignition engine with a variable valve timing device were investigated for liquefied petroleum gas (LPG) and dimethyl ether (DME) under various LPG injection timing conditions. LPG was used as the main fuel injected directly into the combustion chamber. DME was used as an ignition promoter injected into the intake port. Different LPG injection timings were tested to verify the effects of the mixture homogeneity on the combustion and exhaust emission characteristics of the LPG and DME compression ignition engine. The average charge temperature was calculated to analyse the pollutant formation. The ringing intensity was used for the analysis of knock characteristics. The combustion and exhaust emission characteristics differed significantly depending on the LPG injection and intake valve open timings. The carbon monoxide (CO) emission increased as the intake valve opened and LPG injection timings were retarded owing to the local mixture inhomogeneity. However, the particulate matter (PM) emission decreased and the nitrogen oxides (NO x) emission increased as the intake valve open timing was retarded in the diffusion combustion regime. Finally, the combustion efficiency decreased as the intake valve open and LPG injection timings were retarded.

Effect of LPG Injection Methods on Engine Performance

Three methods of injecting liquefied petroleum gas (LPG) were tested on an LPG engine. The injection methods were gaseous phase LPG injection at intake port, liquid phase LPG injection at intake port, and liquid phase LPG in-cylinder direct injection. The experimental results showed that the maximum torque developed with liquid phase LPG-engine direct injection, was 13.8 percent higher than gaseous phase LPG injection at the intake port. It was found that liquid phase LPG direct injection was an effective way to overcome power deterioration of an LPG-engine as compared to a gaseous phase LPG injection supply method.

Performance and emission investigation of a four-stroke liquefied petroleum gas spark-ignition engine generator used in a Malaysian night market

The objective of this study is to investigate and compare the performance and emission characteristics of the liquefied petroleum gas (LPG)-fuelled engine generator and the conventional gasoline-fuelled engine generator. The approach involves converting a gasoline engine generator, commonly used in Malaysian night markets to generate electricity, to the LPG engine generator. A four-stroke SI single-cylinder engine is equipped with an LPG injection system with minor modifications and then tested with both LPG and gasoline fuels. A venturi mixer (carburettor) was designed and in house constructed and then installed to deliver a proper A/ F ratio to the combustion chamber. The commercial computational fluid dynamics software FLUENT was used for simulation of air flow inside the mixer. The converted engine was tested at constant speed for its brake-specific fuel consumption (BSFC), efficiency, exhaust temperature, and exhaust gas emissions. The results show that the performance and emission characteristics of the LPG-fuelled engine are well suited for use in night markets. Average BSFC and average efficiency for the LPG engine over a range of loads were quite similar to those for the gasoline engine: the average BSFC was 0.95 kg/kWh for the LPG engine and 1 kg/kWh for the gasoline engine. The use of LPG as fuel in a gasoline engine causes only a slight reduction in efficiency as a 17 per cent reduction in average efficiency was recorded over the entire load range; however, the LPG engine fared better at higher loads than the gasoline engine for which only as low as a 4 per cent reduction was recorded at high loads. Emission tests seem to verify the minimal pollution products; there are significant reductions in the emission concentration results when LPG is used. Average decreases of 32 per cent for nitrogen oxide, 10 per cent for carbon dioxide, and 40 per cent for carbon monoxide were recorded. Although higher values of hydrocarbon (HC) were recorded, a 50 per cent reduction in HC was found for loads higher than 700 W. The study verified the more favourable features of LPG compared to gasoline as it is one of the best alternative fuels to gasoline for spark-ignition engine generators to solve the air pollution problem in night markets.

Effects of Fuel Injection Timing on Combustion and Emissions of a Spark-Ignition Methanol and Methanol/Liquefied Petroleum Gas (LPG) Engine during Cold Start

The combustion and emission characteristics of spark-ignition (SI) methanol and methanol/ liquefied petroleum gas (LPG) engines under different fuel injection timings during cold start have been studied by means of a cycle-by-cycle control strategy. The results showed that the methanol injection timing, the LPG injection timing, and the LPG injection timing delay relative to the methanol injection timing affect cold-start combustion characteristics and emissions of hydrocarbons, formaldehyde, and unburned methanol significantly. The methanol injection timing, the LPG injection timing, and the LPG injection timing delay relative to the methanol injection timing can be optimized to ensure that most fuels enter into the cylinder in the injection cycle and the following cycle and that reliable ignition and combustion happen in the third cycle. Optimal control of the fuel injection timing and the LPG injection timing delay relative to the methanol injection timing improves firing performances, reduces the hydr...

A study on the injection characteristics of a liquid-phase liquefied petroleum gas injector for air-fuel ratio control

Liquefied petroleum gas (LPG) is widely used as a gaseous fuel in spark ignition engines because of its considerable advantages over gasoline. However, the LPG engine suffers a torque loss because the vapour-phase LPG displaces a larger volume of air than do gasoline droplets. In order to improve engine power as well as fuel consumption and air-fuel ratio control, considerable research has been devoted to improving the LPG injection system. In the liquid-phase LPG injection systems, the injection rate of an injector is affected by the fuel temperature, injection pressure, and driving voltage. When injection conditions change, the air-fuel ratio should be accurately controlled in order to reduce exhaust emissions. In this study, correction factors for the fuel injection rate are developed on the basis of fuel temperature, injection pressure, and injector driving voltage. A compensation method to control the amount of injected fuel is proposed for a liquid-phase LPG injection control system. The experimental results show that the liquid-phase LPG injection system works well over the entire range of engine speeds and load conditions, and the air-fuel ratio can be accurately controlled by using the proposed compensation algorithm.

Effects of injector leakage on liquid propane injection engine performance

This study aims to provide basic technical information for research regarding starting performance improvement by using a 2.656 cm3 V6 liquid propane injection engine to study the effects of varying the liquefied petroleum gas (LPG) leakage on starting performance and to analyse the effects of such leakage on emission characteristics. To determine the LPG injection amount that corresponds to the desired LPG leakage, 1–30 l was injected to find the critical point and, since the injected fuel was detected at the intake starting from 5.5 l, starting performance comparisons of engine speed and exhaust gases were made at 0 l, 1 l, 2 l, 3 l, 4 l, 5 l, and 6 l by measuring the desired value five times and taking the average. Also, to study the effects of a small leak, the starting performance was tested while injecting 0 l, 0.2 l, 0.4 l, 0.6 l, 0.8 l, and 1 l. The major conclusions of this work are as follows: The results of determining the critical point of starting delay for LPG leakages of 1–30 l show that the critical point is 21 l and 14 cycles. For LPG leakages of 1–6 l, the starting time and unburned hydrocarbon (HC) increases with increasing LPG leakage. At LPG leakage of 0.2 l, the starting time is much faster at 1 cycle, but unburned HC increases with increasing LPG leakage.

Mixture distribution and flame propagation in a heavy-duty liquid petroleum gas engine with liquid phase injection

AbstractEnhanced mixture preparation by liquid phase injection on to the port could promote the application of liquefied petroleum gas (LPG) in spark ignition (SI) engines. Mixture distribution and flame propagation of the liquid phase LPG injection (LPLI) engine with a large bore size were investigated in a single-cylinder optical engine which had optical accesses through both sides of the cylinder liner and bottom of the piston. LPG fuel distribution was visualized quantitively by the acetone planar laser-induced fluorescence (PLIF) method. In addition, a series of bottom-view images were taken by direct visualization using a high-speed camera. Flow conditions were varied with the shapes of intake port and piston geometries characterized by different swirl and squish flows. The effects of fuel injection timings were also studied to characterize the mixture preparation for open-valve injection and closed-valve injection.Stronger swirl with a swirl ratio of 3.4 and squish flow with a cylindrical piston bowl shape showed faster flame propagations under the open-valve injection condition with preferable mixture formation. On the contrary, closed-valve injection caused the undesirable mixture distribution of the mixture at the ignition, which led to a leaner mixture distribution near the spark plug.

Mixture distribution and flame propagation in a heavy-duty liquid petroleum gas engine with liquid phase injection

Enhanced mixture preparation by liquid phase injection on to the port could promote the application of liquefied petroleum gas (LPG) in spark ignition (SI) engines. Mixture distribution and flame propagation of the liquid phase LPG injection (LPLI) engine with a large bore size were investigated in a single-cylinder optical engine which had optical accesses through both sides of the cylinder liner and bottom of the piston. LPG fuel distribution was visualized quantitively by the acetone planar laser-induced fluorescence (PLIF) method. In addition, a series of bottom-view images were taken by direct visualization using a high-speed camera. Flow conditions were varied with the shapes of intake port and piston geometries characterized by different swirl and squish flows. The effects of fuel injection timings were also studied to characterize the mixture preparation for open-valve injection and closed-valve injection. Stronger swirl with a swirl ratio of 3.4 and squish flow with a cylindrical piston bowl shape showed faster flame propagations under the open-valve injection condition with preferable mixture formation. On the contrary, closed-valve injection caused the undesirable mixture distribution of the mixture at the ignition, which led to a leaner mixture distribution near the spark plug.

Experimental analysis of a liquid-phase liquefied petroleum gas injector for a heavy-duty engine

Liquefied petroleum gas (LPG) is a well-known clean alternative fuel for vehicles. In a heavy-duty, liquid-phase LPG injection (LPLi) system, several factors influence the amount of fuel injected. These factors are fuel temperature, fuel injection pressure, battery voltage, and so on. In order to maintain the stoichiometric air-fuel ratio in the cylinder during engine operation, the injected fuel quantity should be controlled accurately. In this study, the characteristics of the injector used in the heavy-duty LPLi engine are investigated experimentally. The fuel injection algorithm, which compensates for the variations in the injection pressure, the fuel temperature and the battery voltage, is developed and verified through engine tests.

Alvord [3000 ft Strawn] LPG Flood Design and Performance Evaluation

Summary Mitchell Energy Corp. has implemented a liquefied petroleum gas (LPG)/drive-gas miscible process in the Alvord (3000 ft Strawn) Unit in Wise County, TX, utilizing the U.S. DOE tertiary incentive program. The field has been waterflooded for 14 years and was producing near its economic limit at the time this project was started. This paper presents the results of the reservoir simulation study that was conducted to evaluate pattern configuration and operating alternatives to maximize LPG containment and oil recovery performance. Several recommendations resulting from this study were implemented for the project. On the basis of model predictions, tertiary oil recovery is expected to be between100,000 and 130,000 bbl [15 900 and 20 700 m3]or about 7% of the oil originally in place (OOIP) in the unit. An evaluation of the project performance through Dec.1981 is presented. This portion of the paper was written after drive-gas injection had just been initiated and represents only a preliminary evaluation of the project. In July 1981 the injection of a 16% hydrocarbon pore volume (HCPV) slug of propane was completed. Natural gas is being used to drive the propane slug. A peak oil response of 222 B/D [35.3 m3/d] was achieved in Aug.1981 and production has since been declining. This compares with a peak rate of 400 B/D [63.6 m3/d] during the waterflood, and an oil rate just prior to initiation of LPG injection of 7 B/D [1.1 m3/d]. The observed performance of the LPG flood indicates that the actual tertiary oil recovered will reach the predicted value, although the project life will be longer than expected. The results presented in this paper indicate that, without the DOE incentive program, the economics for this project would still be uncertain at this time. Introduction The Alvord (3000 ft) is approximately 10 miles [16 km]north of the town of Bridgeport in Wise County, TX(Fig. 1). The Alvord (3000 ft) Unit has been successfully waterflooded and was producing near its economic limit in Dec. 1979. A tertiary flood then was considered as an alternative to abandoning the field. Of the tertiary methods available, micellar flooding was eliminated from serious consideration because freshwater was not available and, according to published screening parameters, the calcium and magnesium concentrations were too high in the reservoir and supply water. CO2 was ruled out because of the question of miscibility at this depth and lack of supply. The LPG/drive-gas miscible process was chosen because miscibility could be achieved and convenient sources of LPG and natural gas were available. Economic risks were reduced because the DOE tertiary incentive program was available at that time. The LPG/drive-gas process has produced favourable results in waterflooded reservoirs in the past. The objective of this process in a waterflooded reservoir is to connect the residual oil with the injected LPG and displace it to the producing wells. The water must be displaced by the developing oil bank, the oil must be miscibly displaced by the LPG, and the LPG must be miscibly displaced by the drive gas. The mobility ratio is unfavorable at all flood fronts, and one should expect viscous fingering of the LPG into the oil bank and viscous fingering of the drive gas into the LPG bank. This is an important phenomenon and results in the rapid dissipation of small LPG slugs. When the reservoir is horizontal, the slug dissipation is faster because of stratification and gravity override. When the LPG slug is dissipated, the process reverts to an immiscible gas drive. In the early history of LPG flooding, the use of slugs that were too small probably prevented many projects from being as successful as expected. Several publications indicated that LPG slug sizes, on the order of 10 % HCPV or less, would be adequate for most reservoir situations. Later, others reported that because of viscous fingering, stratification, and gravity override, larger LPG slugs were needed. From the onset of this project it was felt that a successful project required a large LPG slug (about 20%HCPV). It was also recognized that a pattern flood configuration and operating procedure would have to be adopted that would prevent the mobilized oil and the displacing LPG solvent from migrating downdip into the aquifer. Thus a short simulation study was undertaken before embarking on the field project to evaluate alternative flood patterns and operating procedures and to estimate project recovery performance. General Field Description The field is in the central portion of the Fort Worth basin. It produces from an upper Pennsylvanian Strawn series sandstone, the Bryson sand, which was deposited by fluvial processes. A porous sand isopach of the Bryson sand is presented in Fig. 2. JPT P. 119^