Liquefied Petroleum Gas Engine Research Articles

LPG, Gasoline, and Diesel Engines for Small Marine Vessels: A Comparative Analysis of Eco-Friendliness and Economic Feasibility

As an escalating global concern for environmentally sustainable marine fuels, liquefied petroleum gas (LPG) is attracting attention as an eco-friendly and economical alternative. This study explored LPG utilization in small marine vessels, focusing on its eco-friendliness and economic feasibility. To assess its environmental implications, the AVL FIRE simulation program was used to compare CO2, CO, NO, and soot emissions from LPG engines with those from conventional gasoline and diesel engines. The LPG engine model relied on data from a pioneering type-approved experimental LPG engine designed for small South Korean marine vessels, while parameters for gasoline and diesel engines were adjusted to suit their distinctive features. Regarding long-term economic feasibility, assuming a 30-year ship lifespan, incorporating 2022 annual average prices, average annual price growth rates, and annual fuel consumption data of each fuel, results indicate that LPG engines exhibited lower CO2, CO, NO, and soot emissions than conventional engines, except that NO emissions were higher than gasoline engines. Evaluating LPG’s economic feasibility over a 30-year ship life cycle for an individual vessel revealed varying fuel cost savings, with the greatest savings observed in gasoline–other (KRW 2220.7 million) and the least in gasoline–coastal (KRW 1152.5 million). These findings offer vital insights for ship operators and policymakers seeking a balance between eco-friendliness and cost-effectiveness, as well as LPG engine technology emerging as pivotal for a sustainable future, harmonizing environmental protection and economic viability.

Exploring the Impact of Palladium Loading on Pd-Based Three-Way Catalyst Performance and Propane Reactivity for Emission Reduction in Liquefied Petroleum Gas Engines

To reduce air pollution worldwide, regulations on exhaust gas emissions from ships are becoming increasingly stringent. One fuel that is being considered as an alternative to replace the heavy fuel oil used in existing ship engines and thereby reduce harmful emissions, such as NOx, SOx, and greenhouse gases, is sulfur-free liquefied petroleum gas (LPG). To assess the viability of this alternative, it is necessary to understand propane reactivity, the main component of LPG, and develop after-treatment devices applicable to LPG engines. This research evaluated the performance of three prototype Pd-based three-way catalysts (TWCs) with varying Pd loadings (6.5, 4.1, and 1.4 g/L), focusing on their effectiveness concerning propane reactivity in LPG engines. For the fresh samples, catalysts with 4.1 g/L Pd demonstrated performance that was comparable to, or even surpassed, those containing 6.5 g/L Pd. Notably, the temperature of 50% conversion (T50) for NO and C3H8 in the fresh Pd-4.1 was lower by 14 °C and 10 °C, respectively, compared to the fresh Pd-6.5 sample, despite having 37% less precious-metal loading. However, after hydrothermal aging at 900 °C for 100 h, the performance of the 4.1 g/L Pd catalyst significantly deteriorated, exhibiting lower efficiency than the 6.5 g/L Pd catalyst. The study also delved into various probe reactions, including the water–gas shift and propane steam reforming. Advanced analytical techniques, such as N2 physisorption and scanning transmission electron microscopy, were employed to elucidate the texture and structural characteristics of the catalyst, providing a comprehensive understanding of its behavior and potential applications. Through this research, within the efforts of the maritime sector to address challenges posed by emission regulations and rising costs associated with precious metals, this study has the potential to contribute to the development of cost-effective emission control solutions.

Investigation of CO2 and PN emission characteristics according to the propane content for a LPG engine

Many countries of the world aim to achieve carbon neutrality by 2050 and has a set goal for carbon reduction in 2030. Among eco-friendly alternative fuels, engines using liquefied petroleum gas (LPG) have been developed to address regulations. LPG fuel, consisting of a mixture of butane and propane, is currently under investigation to assess how altering the propane content influences fuel atomization, injection quantity, and exhaust gas. This study analyzes the effect of propane content on the engine control strategy and exhaust gas emissions (CO2, particle number (PN)) from LPG fuel based on engine experiments, chassis experiments, and Real-world Driving Emission (RDE) tests. The results indicated that with increased propane content, the injection duration and quantity increased, resulting in increased CO2 emissions but decreased PN emissions. The differences in emission increased according to propane content. Across chassis and RDE tests, higher propane content consistently associated with increased emissions (CO2), while PN consistently stayed at lower levels. The study results offer insights into potential research directions proposed at determining the optimal propane content for minimizing CO2 and PN emissions.

Life Cycle Assessment of LPG Engines for Small Fishing Vessels and the Applications of Bio LPG Fuel in Korea

This study aimed to evaluate the environmental impact of using liquefied petroleum gas (LPG) in small fishing vessels by conducting a life cycle assessment (LCA) in Korea. For the first time in the country, LPG engines designed for small fishing ships were utilized in this study. In addition, this research examined the potential benefits of employing Bio LPG, a renewable LPG produced from two distinct raw materials (crude palm oil (CPO) and refined, bleached, and deodorized (RBD) palm oil), instead of conventional LPG. The LCA findings reveal that utilizing LPG fuel in small fishing vessels can reduce greenhouse gas (GHG) emissions by more than 30% over conventional gasoline and diesel fuels. During the life cycle of vessels that use LPG fuel instead of gasoline and diesel fuels, there is a reduction of 2.2 and 1.2 million tons of GHG emissions, respectively. Moreover, substituting conventional fossil fuels with Bio LPG can result in over 65% reduction in GHG emissions. For the life cycle of boats that use Bio LPG fuel in place of gasoline and diesel fuels, the reduction of GHG emissions was 4.9 million tons and 2.5 million tons for CPO and 5.2 million tons and 2.7 million tons for RBD, respectively. This study not only underscores the substantial advantages of using Bio LPG over conventional fossil fuels but also presents conventional LPG as a way to reduce GHG emissions and promote sustainable practices in the fishing industry.

Experimental study on the effect of load and air+gas/fuel ratio on the performances, emissions and combustion characteristics of diesel–LPG fuelled single stationary ci engine

AbstractDue to the issue of combustion stability when using natural gas and the problem of knocking when using both natural gas and hydrogen, liquefied petroleum gas (LPG) is then a good candidate to use for the dual‐fuel concept since it has been proven to be a good solution to limit the pollutants and the excessive use of fossil resources in the aim to support and advance the African Union's and UN's sustainable development goals. In this paper, the effect of load as well as the air + gas/fuel ratio on the performance, emission, and combustion characteristics of a dual‐fuel diesel–LPG engine, single‐cylinder, four‐stroke, direct injection diesel engine with a rated power of 3.5 kW at a speed of 1500 rpm has been carried out. Experiments have been performed in dual‐fuel mode for a range of loads from 0 to 12 kg and a range of volume flow of LPG from 1 to 5.5 L/min, and the results were compared with those obtained from the single‐fuel mode. Results show that the dual‐fuel mode gives better performance and fewer pollutants than the single‐fuel mode. For example, at low load, Brake thermal efficiency, the indicated thermal efficiency, and mechanical efficiency increased by 83.79%, 24.36%, and 41.77%, respectively, and by 57.48%, 19.84%, and 24.37% at high load when we moved from the single‐fuel mode to the dual‐fuel mode. The smoke, carbon monoxide, and NOx decreased by 24.3%, 94.2%, and 96.2% respectively at low load and by 62.3%, 89.8%, and 91.4% at high load. And, no knocking came up during this research compared to natural gas or hydrogen dual‐fuel engines.

Performance evaluation of the LPG engine applied to catalytic reforming system for producing hydrogen

Despite the global trend toward electrification of powertrains, when life cycle assessment (LCA) is considered, greenhouse gases (GHG) from electric vehicles, fuel cell electric vehicles, and internal combustion engine vehicles are expected to be similar depending on the source of the powerplant. A catalytic reforming system is developed, and its performance is evaluated to maximize the advantages of liquefied petroleum gas (LPG) engines. To optimize the catalytic reforming system, the performance of brake specific fuel consumption and brake specific emissions was evaluated by changing the air fuel ratio. Based on the measured values, various efficiencies were derived and performance was compared to conventional system. When the catalytic reforming system was applied under same operating conditions as the conventional system, fuel consumption and hydrocarbon emissions performance decreased. But they could be overcome by adjusting air fuel ratio. Finally, the best performance improvement was obtained by applying the catalyst reforming system and adjusting the air–fuel ratio to 1.1–1.2.

Research of the impacts of in-cylinder steam injection and ignition timing on the performance and NO emission of a LPG engine

In the study, the effects of in-cylinder steam injection (ICSI) on the liquefied petroleum gas (LPG) engine were investigated in consideration of the impacts of steam on the in-cylinder combustion, to improve its fuel economy and reduce NO. First, a quasi-dimensional model of a baseline engine is established. Then, based on the model, the effects of ICSI on the engine in-cylinder combustion, performance and NO are discussed. After that, according to the impacts of ICSI on the engine, the influences of ignition timing on the engine with ICSI are further analyzed. Finial, with optimum ignition timing, the potentials of ICSI for the engine fuel savings and NO reduction are evaluated. The results show that the laminar flame speed of LPG is decreased by steam. ICSI leads to remarkable increases of flame development angle and rapid burning angle. By adjusting ignition timing, the combustion phase of the engine with ICSI is changed. With optimum ignition timing, engine performance and NO characteristic are remarkably improved by ICSI. At all engine speeds, compared with the baseline engine, with ICSI and optimum ignition timing, the torque is increased by 0.8–6.6%, the BSFC is decreased by 0.6–6.4% and the NO is reduced by 54.0–61.7%.

Experimental study on the performance of a liquefied petroleum gas engine according to the air fuel ratio

The global market of the internal combustion engine is decreasing, and powertrain energy sources will diversify in the next 5–10 years. Alternative fuels are some of the technologies that can be applied immediately to low-pollutant internal combustion engines. Liquid petroleum gas (LPG) is a representative low-pollutant fuel, and its use is increasing worldwide. Therefore, in this study, the fuel consumption, combustion, pollutant emissions, and efficiency performance of an LPG engine were tested and analyzed by adjusting the air fuel ratio, which is the main control parameter of the spark-ignition engine. Finally, the fuel efficiency and pollutant emission performance improved simultaneously by adjusting the air fuel ratio in detail from 1.1 to 1.2. This phenomenon can be applied to internal combustion engine vehicles and LPG-hybrid electrical vehicles and generator engines.

A Theoretical Investigation on the Performance and Combustion Parameters in an Spark Ignition Engine Fueled With Different Shale Gas Mixtures

Abstract In this paper, a zero-dimensional (0D) single-zone combustion model was applied for predicting combustion and indicated engine parameters in a spark ignition (SI) engine. Three different shale gas mixtures, methane, and liquefied petroleum gas (LPG) (30% C3H8–70% C4H10), were studied as SI engine fuel. The shale gas compositions included shale gas-1 (86% CH4–14% C2H6), shale gas-2 (81% CH4–10% C2H6–9% N2), and shale gas-3 (58% CH4–20% C2H6–2% C3H8–10% CO2). Experimental results of the SI engine operated with LPG were used in the model verification phase and provided to the validation of the theoretical model. In addition, the operational parameters of the LPG engine were used as the model input values. The results show that shale gas-1 has the potential to be a good alternative fuel to LPG for SI engines. Shale gas-1 has an indicated mean effective pressure (IMEP) value of 5.7–7.3%, which is lower than LPG in the range of ϕ = 0.83–1.2. Furthermore, LPG has a 27.7% higher indicated specific fuel consumption (ISFC) compared to shale gas-1. On the other hand, LPG has 1.2–2.4 units lower indicated thermal efficiency (ITE) values than shale gas-1 in the range of ϕ = 0.83–1.2. However, Methane, Shale gas-2, and Shale gas-3 have 7.55–9.62%, 20.35–20%, 22.19–21.47 lower IMEPs than LPG in the range of ϕ = 0.83–1.2, respectively.

Assessment of gaseous, particulate, and unregulated emissions from diesel compression ignition and LPG direct injection spark ignition minibus vehicles under the world harmonized vehicle cycle on a chassis dynamometer

Construction of harmful emission inventory from conventional and sustainable low carbon fueled vehicles is important issues to improve urban air quality and human health. In this study, the gaseous, nanoparticle, and unregulated gaseous emission formation behavior from a medium-duty minibus were investigated using the World Harmonized Vehicle Cycle (WHVC). The state-of-the-art diesel and turbocharged direct-injection liquefied petroleum gas (LPG) vehicle were tested on a chassis dynamometer. The after-treatment system of the 3.9-L diesel engine was composed of the DOC, DPF and SCR, which satisfy the Euro 6 emission regulation. The 3.3-L stoichiometric spark ignition direct injection LPG engine was a TWC-only system. The formation of harmful emission components from the light-duty minibus operation was closely related to powertrain types, combustion mechanisms, after-treatment devices, and physicochemical properties of the tested fuels. Additionally, the chemical composition and low heating value (or energy content) of the respective fuels substantially affected the vehicle CO2 emissions and fuel economy performance. Compared to LPG vehicle, the THC and NOx emissions from diesel vehicle were 63% and 511%. Similar PN concentrations were measured with each powertrain, but 2–3 times higher nucleation mode particles were released with diesel vehicle. Two vehicles showed comparable CO2 emissions, while fuel economy from diesel and LPG vehicle were 6.81 km/L and 4.60 km/L. The proportions of N2O and CH4 emissions with ozone forming potential (OFP) were 1.2% (diesel) and 0.3% (LPG), which showed the potential to mitigate the CO2-equivalent emissions from LPG minibus.

Emissions of nitrogen oxides and volatile organic compounds from liquefied petroleum gas-fueled taxis under idle and cruising modes

Liquefied petroleum gas (LPG) as an alternative fuel is increasingly used in mainland China, few reports are however available about emissions from LPG-fueled vehicles. In this study, 26 LPG-fueled taxis in Guangzhou, south China were tested using a chassis dynamometer to obtain their emission factors of nitrogen oxides (NOx) and volatile organic compounds (VOCs) under idle and cruising (10–60 km h−1) modes. The emission factors of NOx on average increased with speed from 4.13 g kg-fuel−1 at idling to 71.1 g kg-fuel−1 at 60 km h−1 at a slope of 10.6 g kg-fuel−1 per 10 km h−1 increase in speed. Alkanes were the most abundant (71.9%) among the VOCs in the exhaust, followed by alkenes (25.2%), ethyne (2.7%), and aromatic species (0.2%). Emission factors of VOCs at idling averaged 8.24 g kg-fuel−1, higher than that of 6.23–7.36 g kg-fuel−1 when cruising at 10–60 km h−1, but their ozone formation potentials (OFPs) were lower at idling (15.8 g kg-fuel−1) than under cruising (19.1–23.8 g kg-fuel−1) largely due to higher emission of more reactive alkenes under cruising mode. Emissions of both NOx and VOCs increased significantly with mileages. Measured emission factors of NOx and reactive VOCs in this study suggested that replacing the gasoline-powered taxis with the LPG-fueled taxis with LPG-gasoline bi-fuel engines and no efficient after-treatment devices would not benefit in reducing the emissions of ozone precursors, and strengthening the emission control for LPG vehicles with dedicated LPG engines and after-treatment converters, as did in Hong Kong, could further benefit in reducing the emission of photochemically active species when using LPG as alternative fuels.

Torque and Power Characteristics of Single Piston LPG-Fueled Engines on Variations of Ignition Timing

Liquefied Petroleum Gas (LPG) is an alternative fuel that has all key properties for the Spark Ignition (SI) engine. However, because of its properties, ignition timing on an LPG SI engine needs to be advanced from the reference angle to get the optimum performance. Therefore, this article presents the torque and power characteristics of a single piston LPG engine on variations of ignition timing. Evaluation of engine performance is carried out at the ignition timing of 15O, 17O, and 19O BTDC. The results showed the highest torque for LPG fuel was 10.64 Nm which was achieved at 3500 rpm with ignition timing of 19O BTDC, while the highest power for LPG fuel was 6.9 hp which was achieved at 5936 rpm with ignition timing of 19O BTDC.

Analysis and simulation of combustion and emission on small engine

Liquefied Petroleum Gas (LPG) has become an interesting topic in the automotive industry to develop the engines with clean emission characteristics. The usage of gasoline as a fuel to power up the vehicle will contribute to the heavy environmental problem. A single cylinder four-stroke spark ignition (SI) engine that fueled by LPG and gasoline are used to predict and analyze the combustion process in the cylinder. A zero dimensional models are most suitable analytical models for engine cycle simulation. The simulation program has been developed using MATLAB software by implementing a single-zone thermodynamic model. The first law of thermodynamics is applying into this model and Annand’s model was used to compute the convection and radiation of heat transfer within the cylinder. The engine performance parameters computed including the in-cylinder pressure, gas temperature, net heat release, mass fraction burn, brake power, torque, indicated specific fuel consumption. Then, exhaust emission in the cylinder was predicted by the formation of emission model. The results of engine performance are compared between gasoline and LPG as a fuel. Results show LPG engine has contributed to the lower HC and NOx emissions compared to gasoline. It proved that the development of simulation program is useful to calculate the engine performance at different operating points.

Evaluation of injection and ignition schemes for the ultra-lean combustion direct-injection LPG engine to control particulate emissions

The high level of particulate emission in ultra-lean combustion direct injection engine was obstacles for real application and satisfying the further upcoming regulation. The use of LPG (liquefied petroleum gas) in lean direct injection engines has the potential to reduce carbon-related emissions owing to its simple structure, and it can become an easily stratified mixture because of its higher vapor pressure. In this respect, the effects of the injection and ignition schemes on combustion and emission characteristics, including particle emission of ultra-lean combustion through LPG, were investigated. Four different injections schemes in order for forming stratified mixture and two ignition schemes (single charge ignition and multi-charge ignition) were employed to achieve simultaneous harmful emissions and fuel consumption reduction.The experimental results reveal that the fully stratified injection strategies indicate an improvement of approximately 18% in thermal efficiency, but combustion fluctuation was observed owing to stratification. Moreover, simultaneous reductions in the NOX (Nitric Oxides) and CO (Carbon monoxide) emissions were observed (when compared to homogeneous stoichiometric combustion) while increasing the particulate matter emission. In order to stabilize the combustion and reduce the level of soot, a multi-charge ignition was introduced to the selected injection strategies (LBM1 and LBM2). Multi-charge ignition successfully reduces particulate mass by about 10% and secures the combustion stability slightly; however, it increases the particle number concentration.

An assessment of the ultra-lean combustion direct-injection LPG (liquefied petroleum gas) engine for passenger-car applications under the FTP-75 mode

Fuel economy and emissions characteristics of the lean-burn combustion strategy were assessed in a direct-injection liquefied petroleum gas engine under urban driving conditions. This study investigated: (1) engine experiments under steady-state conditions that frequently occur during city driving and (2) zero-dimensional drive cycle simulation under the FTP-75 mode. From the engine experiments, two sets of operation maps were constructed for the lean and conventional combustion modes. The lean combustion set consisted of the lean operation between 20 and 80Nm and the stoichiometric operation for the rest of the operating envelope. The selected lean operation range was found to be the largest possible to operate under the lean condition. The entire conventional combustion set was taken at the stoichiometric condition for comparison with the lean combustion set. Then, the steady-state performance maps of the fuel consumption, emissions, and exhaust temperature of the two combustion sets were used in a vehicle model of the cycle simulation. The drive cycle simulation results showed that the fuel economy of the lean combustion set was 10.65km/l, which is lower than that of the conventional combustion set by 6.3%. Carbon dioxide emission was 146.25g/km, down by 8g/km from the conventional combustion set. The time-resolved emissions of the particle mass and particle number of the lean combustion set were 0.005g/km and 3.2×1011#/km, respectively. The particle emissions of the lean combustion set were higher than those of the conventional combustion set, but considered as acceptable levels based on the upcoming emission standards.

1-D transient emission analysis of LPG engine catalytic converter with secondary air injection during cold start period of CVS-75 mode

A 1-D transient emission analysis was performed during the cold start period of the city driving 75 (CVS-75) mode for a liquefied petroleum gas (LPG) vehicle to identify the optimal operating conditions of a secondary air injection (SAI) system. A commercial 1-D program, AMESim, was used to model the full exhaust system, including the SAI system, as well as a manifold catalytic converter (MCC) and an under-body catalytic converter (UCC). Next, the effects of the SAI air flow rate and the supply time on HC, CO, and NO x emissions were analyzed using the simulation model with 7-step global surface chemical reactions of the Langmuir-Hinshelwood type. From the simulated results, we found that a 29% HC reduction and a 50% CO reduction can be achieved with the SAI system under the optimal operation conditions of 1.6 g/s of air flow rate for 30 s.

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.

Experimental Study on LPG Composite Fuel Used on Spark Ignition Engine

Through researching and comparing the combustion characteristics of various gaseous fuels, this paper, based on the characteristics of gaseous fuels, proposes a LPG+H2 composite fuel scheme with liquefied petroleum gas (LPG) as a clean alternative fuel and hydrogen (H2) as an additive fuel on LPG engine, and completes an initial experiment on the gaseous LPG+H2 composite fuel used on engine. It also explores how the air-fuel ratio, ignition timing and ignition energy of the gaseous fuel with three different levels of H2 content influence the dynamic properties and emission characteristics of the engine.

Analysis and validation of a Powertrain System Analysis Toolkit model of a fuel cell hybrid rickshaw

SUMMARY Auto rickshaws are three-wheeled vehicles that are common in Asian cities. Because of the large number of rickshaws on the road and their older two-stroke engines, they have a significant negative impact on urban air quality. Recent changeovers to four-stroke engines as well as diesel, compressed natural gas, and liquefied petroleum gas engines have succeeded in reducing the quantity of pollution and greenhouse gas emissions. However, because of the large number of vehicles, the rickshaw “fleet” still represents a significant source of air pollution. There have been several studies that have examined the feasibility of converting an internal combustion engine (ICE) rickshaw to a photovoltaic or fuel cell (FC) hybrid electric configuration. These studies have typically used or modified a standard urban drive cycle. It is argued that such drive cycles do not accurately portray the demands on a rickshaw. Thus, the results may be misleading. In this study, a model of an ICE rickshaw was created and validated against experimental results. Two drive cycles that would closely emulate the true demands on a rickshaw operated in an urban environment were developed. A model of an FC hybrid rickshaw was created and tested. The effects of FC and battery capacities as well as the electric motor type on performance were studied. A comparison between ICE and FC hybrid rickshaw configurations was done using a realistic drive cycle. The ICE and the FC hybrid rickshaw models were created and assessed using the Powertrain System Analysis Toolkit software package. Copyright © 2011 John Wiley & Sons, Ltd.

Study on LPG Air Fuel Ratio Based on Improved Subtractive Clustering RBF Neural Networks

The paper refers to the mathematical model of gasoline engine, and builds liquid-jet LPG(Liquefied Petroleum Gas) engine model. Based on the model, when the specific of the parameters distribution of operating engine are known, RBF neural network can estimate center value and the number of hidden layers precisely, and control engine A/F in fine range. But the parameter features of operating engine are unknown in advance. The paper provides a improved subtractive clustering - RBF neural Networks algorithm to control A/F of LPG engine. Simulation shows, improved subtractive clustering can precisely determine the number of neuron of RBF neural network hidden layers under unknown operation parameters, and the precision is higher, and self-study and adaptive adjusting is better than before.