Liquefied Petroleum Gas Injection Research Articles

Experimental Assessment of the Performance and Fine Particulate Matter Emissions of a LPG-Diesel Dual-Fuel Compression Ignition Engine

The present work is focused on the assessment of the performance and fine particulate matter emissions (PM2.5) of a turbocharged four-cylinder direct injection diesel engine operating under dual-fuel mode with Liquefied Petroleum Gas (LPG). For load levels of 30%, 60% and 100%, measurements were taken, keeping the engine speed constant at 2200, 2500 and 3200 rpm, while the engine knock detonation was detected through a non-invasive internal system. According to experimental measurements, the abnormal knock combustion occurred at full load operation with a maximum LPG energy fraction of ~60%. The brake fuel conversion efficiency increased by 2.6% with an LPG energy fraction of 10%, where a fuel saving of 11.9% was achieved with respect to the diesel-only operation. The reduction of diesel consumption was around 50% with respect to 100% diesel operation at full load operations, where the highest brake fuel conversion efficiency was achieved. The brake fuel conversion efficiency decreased as LPG addition increased for all the engine loads. Regarding emissions, PM2.5 decreased with the addition of LPG. However, HC and CO emissions increased as LPG injection was higher. NOx emissions and exhaust gas temperatures were reduced for operation with higher LPG fractions, except for full load levels at 2200 and 2500 rpm.

Modeling of CO2-LPG WAG with asphaltene deposition to predict coupled enhanced oil recovery and storage performance

Combined carbon capture and storage and CO2-enhanced oil recovery (CCS-EOR) can reconcile the demands of business with the need to mitigate the effects of climate change. To improve the performance of CCS-EOR, liquefied petroleum gas (LPG) can be co-injected with CO2, leading to a reduction in the minimum miscibility pressure. However, gas injection can cause asphaltene problems, which undermines EOR and CCS performances simultaneously. Here, we systematically examine the mechanisms of asphaltene deposition using compositional simulations during CO2-LPG–comprehensive water–alternating-gas (WAG) injection. The LPG accelerates asphaltene deposition, reducing gas mobility, and increases the performance of residual trapping by 9.2% compared with CO2 WAG. In contrast, solubility trapping performance declines by only 3.7% because of the greater reservoir pressure caused by the increased formation damage. Adding LPG enhances oil recovery by 11% and improves total CCS performance by 9.1% compared with CO2 WAG. Based on reservoir simulations performed with different LPG concentrations and WAG ratios, we confirmed that the performance improvement of CCS-EOR associated with increasing LPG and water injection reaches a plateau. An economic evaluation based on the price of LPG should be carried out to ensure practical success.

Development of an LPG Injection System for SI Engines

Recently, in the context of increasing global energy demand and environmental problems, many researchers have proposed effective solutions for transportation in the current situation. Liquefied petroleum gas (LPG) has been considered as a preferred alternative fuel for spark-ignition (SI) engines. This study describes the development of an LPG injection system for an SI engine. The proposed system was based on the analysis of fuel requirement and metering for the engine operating with LPG, as well as the effect of engine parameters on the LPG flow rate. The system cooperates with the gasoline ECU to produce the signals controlling LPG injectors. An experiment was conducted with an SI engine under different conditions of loads and engine speeds. Experimental results showed that the LPG injection system adapted all test conditions, the engine ran smoothly at all test speeds and partial opening throttle. Fueling with LPG, engine torque and energy conversion efficiency were higher, whereas exhaust gas emissions such as HC, CO, and NOx were lower compared with that as fueled with gasoline.

The Impact of Diesel/LPG Dual Fuel on Performance and Emissions in a Single Cylinder Diesel Generator

Compared to other engines of the same size, diesel engines are more economical in addition to their ability to generate high power. For this reason, they are widely used in many fields such as industry, agriculture, transportation, electricity generation. The increasing environmental concerns and diminishing oil resources led researchers to improve fuel consumption and emissions. In this context, the usage of Liquefied Petroleum Gas (LPG) fuel in diesel engines is one of the important research subjects that has been keeping up to date. This paper investigates the effects of LPG direct injection towards the end of air inlet period on engine emissions and performance characteristics. A four-stroke, air cooled, single cylinder diesel engine was modified to direct injection of LPG for diesel/LPG dual fuel operation. An Electronic Control Unit (ECU) was designed and used to adjust LPG injection timing and duration. LPG injection rates were selected as 30%, 50% and 70% on a mass base. The test engine was operated at 3000 rpm constant engine speed under varying load conditions. Throughout the experiments, it was observed that smoke density significantly reduced on the dual-fuel operation, compared to the pure diesel operation. Carbon Monoxide (CO) and Hydrocarbon (HC) emissions decreased by 30% and 20%, respectively. Brake Specific Fuel Consumption (BSFC) decreased by 8%. Nitrogen Oxide (NOx) emissions increased by 6% while effective efficiency increased up to 1.25%.

Investigating the influences of liquid LPG injection on spark ignition (SI) engine

Liquefied petroleum gas (LPG) is one of the alternative fuels that becoming popular to be use in spark ignition engine (SI). This paper briefly presents the influence of energy content to the engine output of 1.6L SI engine of Proton Gen 2. The engine was coupled to a chassis dynamometer and few related apparatus were employed in determine the engine behavior. All data collected were illustrated in graph for further analysis. The engine shows comparable engine output, however, the engine requires some tuning in order to fully utilize the energy content of LPG.

Experimental study on the icing characteristics of LPLi injectors under various injection conditions

Development of alternative fuels has been increasing to replace conventional fuels because of severe environmental pollution from the exhaust emissions of ground vehicles and the depletion of fossil fuels. LPG (Liquefied petroleum gas) fuel provides clean energy for gasoline-fueled engines and LPG fuel R&D (Research & development) has actively progressed in reaching the application stage. However, the icing phenomenon in liquid-phase LPG injection systems remains a major problem. The purpose of this study was therefore to investigate the temperature distribution on the icing protection tip and icing formation characteristics under various test conditions (i.e. injection pressure, injection frequency, injection duty). The results showed that increasing the injection frequency induced a big the temperature drop, whereas increasing the injection duty decreased the temperature drop under the same test conditions. Increasing the injection pressure caused a small temperature drop because of an increase in the injection velocity, which meant that much of the injected LPG evaporated at a region distant from the nozzle tip. The protection tip with a double-hollow structure had a smaller the temperature drop than the all-in-one type protection tip made of the same material (copper).

Critical firing and misfiring boundary in a spark ignition methanol engine during cold start based on single cycle fuel injection

The influence of the mass of methanol injected per cycle, ambient temperature, injection and ignition timing, preheating methods, and supplying additional liquefied petroleum gas (LPG) injection into the intake manifold on the critical firing and misfiring boundary of an electronically injection controlled spark ignition (SI) methanol engine during cold start were investigated experimentally based on a single cycle fuel injection with cycle-by-cycle control strategy. The critical firing and misfiring boundary was restricted by all parameters. For ambient temperatures below 16 °C, methanol engines must use auxiliary start-aids during cold start. Optimal control of the methanol injection and ignition timing can realize ideal next cycle firing combustion after injection. Resistance wire and glow plug preheating can provide critical firing down to ambient temperatures of 5 °C and 0 °C, respectively. Using an additional LPG injection into the intake manifold can provide critical firing down to an ambient temperature of −13 °C during cold start. As the ambient temperature decreases, the optimal angle difference between methanol injection timing and LPG injection timing for critical firing of a methanol engine increases rapidly during cold start.

Designing a Prototype LPG Injection Electronic Control Unit for a Carburetted Gasoline Engine

In this study, the originally carburetted gasoline engine was converted to gas-phase liquefied petroleum gas (LPG) injection engine by using an after market LPG conversion kit's components except the electronic control unit (ECU). Instead of after market LPG injection ECU, the ECU which was designed considering the effects of electromagnetic interference (EMI), was used for controlling injection. The designed ECU was tested in terms of EMI while the engine was being run and it was detected that the EMI noises could be suppressed as possible by taken measures. Designed ECU was used in performance tests at different engine conditions and the results obtained with LPG injection were compared with the results obtained with LPG carburetion. According to the performance test results, LPG injection ECU designed in this study could help to achieve low exhaust emissions and high engine performance.

Effects of the sulfur content of liquefied petroleum gas on regulated and unregulated emissions from liquefied petroleum gas vehicle

A more stringent standard for sulfur in liquefied petroleum gas (LPG) is currently being considered by the Ministry of Environment of Korea. Therefore, we investigated the characteristics of exhaust emissions from liquid phase LPG injection passenger car depending on the sulfur content of the LPG. Using a chassis dynamometer test with exhaust gas analyzers and Fourier-transform infrared spectroscopy, regulated emissions of carbon monoxide, non-methane hydrocarbons, and nitrates were investigated, as well as unregulated emissions of CH4, N2O, NH3, and SO2. Vehicle tests were carried out using Federal Test Procedure 75 (FTP-75) and Highway Fuel Economy Test (HWFET) cycles and time-resolved exhaust emissions and mass emissions were analyzed. The concentrations of regulated and unregulated time-resolved emissions increased during the cold start phase (Phase 1) of the FTP-75 cycle, in which the catalyst does not reach the light-off temperature. In the FTP-75 and HWFET cycles, most of the regulated and unregulated mass emissions increased as the sulfur content of the LPG increased. The SO2 concentration in the emissions increased in proportion to the sulfur content in the LPG, particularly in the high-speed portion of the FTP-75 cycle.

On-board measurement of emissions from liquefied petroleum gas, gasoline and diesel powered passenger cars in Algeria

On-board measurements of unit emissions of CO, HC, NOx and CO2 were conducted on 17 private cars powered by different types of fuels including gasoline, dual gasoline–liquefied petroleum gas (LPG), gasoline, and diesel. The tests performed revealed the effect of LPG injection technology on unit emissions and made it possible to compare the measured emissions to the European Artemis emission model. A sequential multipoint injection LPG kit with no catalyst installed was found to be the most efficient pollutant reduction device for all of the pollutants, with the exception of the NOx. Specific test results for a sub-group of LPG vehicles revealed that LPG-fueled engines with no catalyst cannot compete with catalyzed gasoline and diesel engines. Vehicle age does not appear to be a determining parameter with regard to vehicle pollutant emissions. A fuel switch to LPG offers many advantages as far as pollutant emissions are concerned, due to LPG's intrinsic characteristics. However, these advantages are being rapidly offset by the strong development of both gasoline and diesel engine technologies and catalyst converters. The LPG's performance on a chassis dynamometer under real driving conditions was better than expected. The enforcement of pollutant emission standards in developing countries is an important step towards introducing clean technology and reducing vehicle emissions.

Liquefied petroleum gas (LPG) as a medium-term option in the transition to sustainable fuels and transport

Abstract Undoubtedly, the changes spark ignition engines (hereinafter SI engines, Otto engines) have undergone under the last 20–25 years has been due to pressure from emission standards and fuel economy requirements becoming ever stricter. These regulations have equally influenced the every stage (from 1st to 5th generation) of LPG technology development while looking back in retrospective. Increasing emphasis on liquefied petroleum gas (LPG) as a clean, relatively low in cost and abundant energy source to provide affordable fuel-efficient transportation, encourages the search for the optimum approach to management of fuel, air and combustion to achieve the best results in vehicle power, fuel efficiency and low gaseous waste products. The development undertaken since then is still a “work in progress” leading to the course of establishing the new systems, including those for Otto engines with direct gaseous fuel injection as well as direct liquid LPG injection. In performing the analysis of LPG fuel systems (the 1st, 2nd, 3rd, 4th, and 5th) for internal combustion engines (ICEs), special emphasis is put upon the thorough examination of their structural control diagrams. The critical review also provides a detailed description of characteristics and classification of fossil derived gases (LPG, CNG, and LNG) as fuels in motor vehicles, discusses different types of existing LPG fuel delivery systems and requirements to gas equipment, and presents a thorough analysis of the SI engine operation using LPG as a fuel.

A comparative study of carburation and injection fuel supply methods in an LPG-fuelled SI engine

In this study, a four-stroke carburettor spark-ignition (SI) engine was run using a specially designed, electronically controlled gas-phase manifold liquefied petroleum gas (LPG) injection system in a set of experiments conducted to compare the performance of different fuels and mixing systems. Experiments were carried out at 2000–4000rpm and fixed throttle positions of 25% and 50% of full opening to determine performance parameters. During the tests, carried out in a test bed with a specially designed, electronically controlled LPG injection unit, the excess air coefficient was maintained within the range of 0.95–1.05 because the best emissions results are generally obtained in this range. The results obtained with LPG injection were compared with the results obtained for gasoline and LPG carburetion. The test results showed that the LPG gas injection system developed in this study can help to achieve higher engine power outputs, lower specific fuel consumption and lower exhaust emissions.

The Performance Analysis of LPG as the Vehicle Fuel

As the global shortage of oil resources and the rapid increase in car ownership, using gas as the alternative fuel is getting more and more important. Gas fuel, such as CNG (compressed natural gas)/LNG (liquefied natural gas) and LPG (liquefied petroleum gas), with resource-rich, less pollution and other features, are desirable alternative fuels for cars. Through engine bench test, a comparative analysis of power performance between LPG-single fuel engine and gasoline engine was done. The result shows that, by applying LPG injection on single-fuel engine, the power of the LPG engine increases to a higher level than gasoline engines. And combined with the analysis based on the study of domestic development of NGV, predictions could be made that new fuel vehicles will be well utilized in future.

An investigation of icing in a liquid petroleum gas liquid phase fuel injector with a shut-off valve

Liquefied petroleum gas (LPG) engines are considered to be a clean energy source. The fuel supply strategy for this type of engine is moving away from a mixer-type fuel supply and towards an LPLI (liquid phase LPG injection) system, which injects liquid phase LPG directly into the manifold, enhancing volumetric efficiency, giving a faster response, and providing more precise fuel control. The LPLI system requires a new development to meet more stringent emissions regulations than previous regulations. This new development is motivated by the tendency of LPG in an LPLI system to leak out of the injector after the engine is shut off. Installing a shut-off valve directly after the injector is one possible strategy for preventing this leakage. To install the shut-off valve in the injector, it is necessary to change its structure. In a prototype of the shut-off valve type injector, the fuel path inside the adapter becomes longer and more complicated than in a conventional LPLI injector, which may cause icing at the injector tip. Because LPG absorbs heat for evaporation when it is injected into the manifold, the temperature of the injector tips is decreased to a temperature even below freezing. Water vapour in the intake air passing the cold injector can form ice that sticks on the surface of the injector. This phenomenon is called icing and can become disruptive to precise air/fuel control as ice particles fall off and enter the cylinder. Using injection visualization, emissions analysis, and data on engine running conditions, these icing phenomena are classified into two types: one at the cold adapter surface and the other at the LPG transfer tube (a Teflon tube) tip, which is placed in the centre of the injector adapters. The icing phenomena in shut-off valve type LPLI injectors are significantly reduced by enhancing heat transfer between the cold injector tip and the hot intake manifold, and by surrounding the injecting tip with a shroud.

Experimental evaluation of combustion phenomena in and nanoparticle emissions from a side-mounted direct-injection engine with gasoline and liquid-phase liquefied petroleum gas fuel

This study focuses on the experimental comparison of combustion phenomena and nanoparticle emission characteristics from a wall-guided direct-injection (DI) spark ignition engine for gasoline and liquefied petroleum gas (LPG). A returnless gasoline direct-injection (GDI) fuel supply system was reworked for the return-type liquid-phase LPG injection fuel supply system that was composed of an LPG tank with a brushless d.c. pump and a low-pressure regulator to supply the stable liquid-phase LPG for the DI engine. To verify the clean combustion characteristics of the LPG DI engine, nanoparticle concentrations obtained with a differential mobility spectrometer and the total hydrocarbon and nitrogen oxide emission levels were compared with those of a gasoline-fuelled engine. The maximum performance and the part-load combustion phenomena of the two fuels were evaluated. In conclusion, the nanoparticle and exhaust emissions of the LPG DI engine were much lower than those of the GDI engine. Furthermore, the combustion performance of LPG in the full-load condition was comparable with that of the gasoline fuel, and the combustion stability in a part-load condition of LPG was better than that of gasoline because it evaporated very rapidly and mixed well with the air. As a result, a substantial reduction in the fuel wetting in the combustion chamber was achieved.

LPLi 시스템에서 외장형 펌프의 연료조성 및 온도에 따른 성능특성 연구

LPG 연료공급방식은 배출가스를 저감시킬 수 있는 유용한 시스템으로 연구가 지속적으로 진행되고 있다. LPG는 경유와 휘발유보다 높은 증기압과 낮은 점도와 표면장력을 유지하므로 고무류와 화학반응에 따른 연료펌프의 기계적인 손상으로 내구성이 저하되고 있는 실정이다. 본 연구에서는 이러한 문제점을 해결하기 위해 LPLi 시스템에서 유지보수의 편리함과 가격경쟁을 위해 개발된 외장형 펌프를 사용하여 LPG 연료의 조성 및 온도에 따른 특성을 평가하고자 실험을 하였다. 그 결과로서, 내장형 펌프와 외장형 펌프의 성능차이는 거의 없으며 프로판 함유율이 높고, 연료온도가 높아짐에 따라 유량은 많아지나 펌프효율은 거의 차이가 없었다. 또한 LPG 자동차 연료공급장치의 특성상 연료조성 및 온도변화에 따른 차압도 거의 일정하게 나타내었다.

Lubrication characteristics of spiral groove liquid seals for use in the carrier of a vane-type external LPG fuel pump

We analyzed the lubrication characteristics of a design-selected spiral groove liquid seal for the critical component, the carrier, of a rotary vane-type fuel pump developed for external installation on fuel tanks for liquid phase LPG (liquefied petroleum gas) injection (LPLi) vehicles, with the aim of fundamentally improving lubrication performance and so protecting the carrier from early frictional wear damage at its suction face. The main reason for selecting a spiral groove pattern was because the viscosity of liquid LPG is very low, comparable to that of air, and current commercial dry gas seals adopting spiral grooves have been successfully employed in completely noncontacting applications. Utilizing the Galerkin finite element lubrication analysis method, a detailed lubrication characteristic analysis of the seal was performed, and lubrication performance optimization was performed by systematic parameter analyses of the design variables. Compared to the initial reference design, the final optimized spiral groove seal design had a groove depth increased by 66.7% and an equilibrium seal clearance increased by 65.3%. Our model also predicted that under a condition of equilibrium between the closing force of the pumping pressure and the seal opening force, the optimally designed carrier spiral groove liquid seal was capable of maintaining a stable lubricating film with sufficient axial stiffness and thereby demonstrated successful noncontact operation; in addition, leakage through the seal was minimal.

Catalyst light-off behavior of a spark-ignition LPG (liquefied petroleum gas) engine during cold start

The effects of the length of the gas flow path from the exhaust outlet in the cylinder head to the catalyst inlet in the exhaust line, the ignition timing and the engine idle speed on the three-way catalyst light-off behavior in an electronically controlled inlet port LPG (liquefied petroleum gas) injection SI (spark-ignition) engine during cold start were investigated experimentally. The results showed that these factors affect the catalyst light-off behavior significantly during cold start. The reduction of the gas flow path length upstream the catalyst reduces the heat loss from the exhaust gases, increases the temperature of the catalyst, and results in faster catalyst light-off. Retarding the ignition timing from 0 to 15°CA ATDC decreases 22 and 8 s catalyst light-off time for HC and CO respectively. Increasing the engine idle speed from 1400 to 1800 rpm decreases 19 and 15 s the light-off time for HC and CO respectively. ► The evaluation methods of the temperature and conversion efficiency are essential for catalyst light-off. ► We adopt HC and CO emission to explain the catalyst light-off during cold start. ► The reduction of the gas flow path length upstream, retarding the ignition timing and increasing the engine idle speed can reduce the catalyst light-off time during cold start. ► We concluded that improving methods for catalyst light-off are essential for the catalyst light-off behavior during cold start.

Design and optimization of an LPG roller vane pump for suppressing cavitation

A roller vane type liquefied petroleum gas (LPG) pump was developed for a liquid phase LPG injection (LPLi) engine. Most of the LPG pumps used in the current LPLi engines are installed inside of the LPG tank, but this pump is intended to be installed outside of the LPG tank to overcome the difficulty of fixing an in-tank pump. Because LPG has a low boiling point and high vapor pressure, it usually causes cavitation in the pump and consequently deteriorates the flow rate of the pump. The purpose of this work is to optimize the design of the roller vane pump in order to suppress cavitation and increase the fuel flow rate by using a computational fluid dynamics (CFD) analysis. In order to achieve these goals, the intake port configuration and the rotor of the roller vane pump were redesigned and simulated using STAR-CD code. Computation was performed for six different models to obtain the optimized design of the roller vane pump at a constant speed of 2600 rpm and a constant pressure difference between the inlet and outlet of 5 bar. The computation results show that an increased intake port cross-section area can suppress cavitation, and the pump can achieve a higher flow rate when the rotor configuration is changed to increase its chamber volume. When the inlet pressure difference is 0.1 bar higher than the fluid saturation pressure, the pump reaches its maximum flow rate.

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.