Browse Topic: Liquefied petroleum gas
Decarbonizing regional and long-haul freight is challenging due to the limitations of battery-electric commercial vehicles and infrastructure constraints. Hydrogen fuel cell medium- and heavy-duty vehicles (MHDVs) offer a viable alternative, aligning with the decarbonization goals of the Department of Energy and commercial entities. Historically, alternative fuels like compressed natural gas and liquefied propane gas have faced slow adoption due to barriers like infrastructure availability. To avoid similar issues, effective planning and deploying zero-emission hydrogen fueling infrastructure is crucial. This research develops deployment plans for affordable, accessible, and sustainable hydrogen refueling stations, supporting stakeholders in the decarbonized commercial vehicle freight system. It aims to benefit underserved and rural energy-stressed communities by improving air quality, reducing noise pollution, and enhancing energy resiliency. This research also provides a blueprint for replacing diesel in over-the-road Class 8 freight truck applications with hydrogen fueling solutions. The study focuses on the Texas Triangle Megaregion (I-45, I-35, and I-10), the I-10 corridor between San Antonio, TX, and Los Angeles, CA, and the I-5/CA-99 corridors between Los Angeles, CA, and San Francisco, CA. This area represents a significant portion of U.S. heavy-duty freight movement, carrying ~8.5% of the national freight volume. Using the OR-AGENT (Optimal Regional Architecture Generation for Efficient National Transport) modeling framework, the study conducts an advanced assessment of commercial vehicles, road and freight networks, and energy systems. The framework integrates data on freight mobility, traffic, weather, and energy pathways to deliver a region-specific, optimized vehicles powertrain architectures, infrastructure deployment solutions, operational logistics, and energy pathways. By considering all vehicle origin-destination pairs utilizing these corridors and all feasible fueling station location options, the framework's genetic algorithm identifies the minimum number and optimal locations of hydrogen refueling stations, ensuring no vehicle is stranded. It also determines fuel schedules and quantities at each station. A roadmap for station deployment based on multiple adoption trajectories ensures a strategic rollout of hydrogen refueling infrastructure.
During the 20th century, the energy landscape in India was dominated by fossil fuels, with diesel, petroleum, and kerosene used for most industrial and domestic purposes. In rural India, a large part of the population was still using coal, wood, or dung fires for cooking. However, the last few decades have seen the country strive to become a more gas-based economy, with widespread use of liquefied petroleum gas (LPG) and compressed natural gas (CNG) for cooking and even transportation. Recently, piped natural gas has also been made available to many urban households, providing the comfort of uninterrupted cooking gas directly to consumer homes. This new development calls for the gas utility providers to measure how much gas is being consumed. How? With the help of gas meters.
In prior work, the EGR loop catalytic reforming strategy developed by ORNL has been shown to provide a relative brake engine efficiency increase of more than 6% by minimizing the thermodynamic expense of the reforming processes, and in some cases achieving thermochemical recuperation (TCR), a form of waste heat recovery where waste heat is converted to usable chemical energy. In doing so, the EGR dilution limit was extended beyond 35% under stoichiometric conditions. In this investigation, a Microlith®-based metal-supported reforming catalyst (developed by Precision Combustion, Inc. (PCI)) was used to reform the parent fuel in a thermodynamically efficient manner into products rich in H2 and CO. We were able to expand the speed and load ranges relative to previous investigations: from 1,500 to 2,500 rpm, and from 2 to 14 bar break mean effective pressure (BMEP). Experiments were conducted to determine the effects of the H/C ratio of the fuel on H2 production and on the engine efficiency in order to compare E10 gasoline (H/C = 1.95) and liquified petroleum gas (LPG), comprised primarily of propane (H/C = 2.67). Additionally, the compression ratio of the engine was increased to ascertain whether further efficiency improvements could be realized based on a reduced knock propensity of the dilute EGR mixture with the reformed fuel. Both the gasoline and propane reforming strategies provided efficiency gains up to 1.85 percentage points and further efficiency improvements with the increased compression ratio were realized. The fuel specific effects of gasoline vs. LPG, the effect of engine operating condition on reforming, and knock limits of the reformed mixture are discussed in detail.
The European Union has defined legally binding CO2-fleet targets for new cars until 2030. Therefore, improvement of fuel economy and carbon dioxide emission reduction is becoming one of the most important issues for the car manufacturers. Today’s conventional car powertrain systems are reaching their technical limits and will not be able to meet future CO2 targets without further improvement in combustion efficiency, using low carbon fuels (LCF), and at least mild electrification. This paper demonstrates a highly efficient and performant combustion engine concept with a passive pre-chamber spark plug, operating at stoichiometric conditions and powered with liquefied petroleum gas (LPG). Even from fossil origin, LPG features many advantages such as low carbon/hydrogen ratio, low price and broad availability. In future, it can be produced from renewables and it is in liquid state under relatively low pressures, allowing the use of conventional injection and fuel supply components. To take advantage of the specific capabilities of LPG a combustion system is designed to increase combustion efficiency and decrease fuel consumption and engine-out emissions. The applied combustion chamber geometry, including the passive pre-chamber, leads to lower exhaust gas temperatures and consequently higher peak power when operating under stoichiometric conditions. The presented combustion system was developed by means of extensive 3D-CFD simulations and experimental single-cylinder engine results by applying advanced combustion diagnosis and analysis tools. The potential of the combustion system is demonstrated over the entire engine map focusing on certification and real operating conditions such as idle, low load and maximum power. The potential of the combustion process will be figured out, both for low and high-power densities, with respect to future emission limitations.
It has been shown that appropriate regulation of parameters of the gas supply system control algorithm allows to reduce the emission of selected components of the exhaust gas (carbon monoxide [CO], hydrocarbon [HC], and oxides of nitrogen [NOx]). The test engine met the Euro 6 standard on petrol and was equipped with an additional alternative multipoint fuelling system for multipoint injection (MPI) of the gaseous phase liquefied petroleum gas (LPG). The tests are comparative in nature. The first test to compare LPG petrol fuelling was carried out in the New European Driving Cycle (NEDC) where small differences in emissions were shown. The second part of the test compared emissions in the Worldwide harmonized Light vehicles Test Cycle (WLTC), wherein the initial phase there was a significant difference in emissions to the detriment of the gas supply. An innovative approach was therefore proposed to correct settings in the gas system control algorithm. In the first option, the settings for the multiplier of the opening time of LPG and petrol injectors were adjusted, resulting in a decrease in HC and NOx emissions with an increase in CO. In the second variant, the connection between the reducer and the engine intake manifold was removed, which increased the HC and NOx emissions, with a decrease in CO compared to the previous variant. In the third variant, the connection between the reducer and the engine intake manifold was restored and several coolant temperature threshold adjustments were made when switching from petrol to LPG. As a result of the corrections made in the gas system control algorithm during WLTC implementation, HC emissions were lower by 10.2%, CO by 21.2%, and NOx by 68.2% compared to the initial test.
The exhaust emission from modern vehicles is reduced by catalysts except for cold start phase. The difference in emissions for unheated catalysts is large and can reach several times higher than the emission for the heated thermal state of the engine. In the dyno tests, the analysis of the duration and volume of the emissions for harmful exhaust components: CO2 (carbon dioxide), CO (carbon monoxide), THC (total hydrocarbons), NOx (nitrogen oxides) at various climatic chamber operating temperatures, i.e. 0-30oC, for a vehicle meeting the EURO3 and EURO6 standards was performed. Stationary analyzers AVL AMA i60 were used to measure the emissions. The article presents the differences in the emissions for the cold-start phase of engine operation and the duration of time passing to a heated engine for vehicles powered by petrol and LPG (liquefied petroleum gas). The work shows the analysis of modal emissions as well as bag emission.
The cottonseed oil, soybean oil and their methyl esters have been used as a pilot fuels for dual fuel engine running on the LPG as the main fuel. A variable compression research diesel engine has been converted to run on dual fuel of LPG and a pilot fuel derived from the renewable liquid fuels above. The engine has been instrumented to measure the combustion pressure, crank angles, exhaust temperature, flow rates of air, pilot fuel and gaseous fuel. The effects of changing the following parameters have been studied: the mass of pilot fuel, the mass of gaseous fuel, the pilot fuel injection timing, engine speed and the pilot fuel type. Five different pilot fuels has been tested here namely the cottonseed raw oil, the cottonseed methyl ester, the soybean raw oil, the soybean methyl ester and the diesel fuel as a reference fuel. The results presented included the combustion noise (as maximum pressure rise rate), the heat release rate, the maximum combustion pressure, the exhaust temperature, the brake and indicated mean effective pressures. It has been found that the renewable pilot fuel properties affected the combustion process and the combustion noise. The best fuel in terms of highest output and minimum noise has been put forward.
The utilization of gaseous fuels in internal combustion (IC) engines is receiving more significant greater interest in recent years because of their better fuel mixing characteristics. Apart from potential gaseous fuels such as liquefied natural gas (LPG), compressed natural gas (CNG), and hydrogen, other alternatives are being explored for their utilization in IC engines. The reason for this exploration is mainly because of the durability and robust nature of compression ignition (CI) engines, and more research focuses on the utilization of a variety of gaseous fuels in CI engines. However, gaseous fuels need to be used in CI engines on dual fuel mode only. In this investigation, a single-cylinder, four-stroke, air-cooled diesel engine was converted into Acetylene run dual-fuel CI engine by changing the intake manifold of the test engine. Acetylene at three flow rates viz., 2lpm, 4lpm, and 6lpm were introduced into the intake port by manifold induction technique while Jatropha biodiesel/diesel was injected directly into the cylinder. In this paper, the effect of manifold induction of Acetylene on the performance and emission characteristics of the test engine was assessed and compared with those of conventional diesel operation of the test engine.
This paper provides a summary of a Liquefied Petroleum Gas (LPG) concept engine developed for medium duty applications (class 6-7 trucks) targeting high efficiency with a power density that matches turbocharged diesel engines. The turbocharged in-line 6 cylinder engine incorporates an advanced spark ignition combustion system design, a purpose built medium-duty class engine structure optimized for operation with a direct propane injection system, dual overhead cams with individual cam phasers and twin-entry turbocharger. The high tumble charge motion combustion system targeted for operation with direct injected (DI) LPG has resulted in an engine capable of producing up to 22 bar brake mean effective pressure (BMEP) at high brake thermal efficiency (BTE) throughout the operating map. The high BTE combined with low carbon to hydrogen ratio of LPG results in 12% lower Brake Specific CO2 (BSCO2) emissions on the heavy-duty FTP cycle when compared to a diesel engine of same displacement and power and 15-30% lower BSCO2 when compared to other commercially available medium-duty LPG engines. The present work demonstrates total cost savings between 1 and 40% (depending on the cost differential between LPG and diesel) over 10 years on a drive cycle represented by the FTP cycle when compared to a diesel engine with similar displacement and torque curve. The ability to run at or close to Maximum Brake Torque (MBT) spark timing along with low pumping losses have ensured high BTE over the entire operating region of the engine.
Recently, it has been worth pointing out the relevance of alternative fuels in the improvement of air quality conditions and in the mitigation of global warming. In order to deal with these demands, in recent studies, it has been considered a great variety of alternative fuels. It goes without saying that the alternative fuels industry needs the best of the efficiency with a moderate layout. From this perspective, Liquefied Petroleum Gas (LPG) could represent a valid option, although it is not a renewable fuel. In terms of polluting emissions, the LPG can reduce nitrous oxides and smoke concentrations in the air, a capability that has a relevant importance for the modern pollution legislation. LPG is well known as an alternative fuel for Spark Ignition (SI) engines and, more recently, LPG systems have also been introduced in the Compression Ignition (CI) engines in dual-fuel configuration. In this research, LPG-Diesel liquid-blend has been used to power a CI engine in mixed fuel configuration. For this purpose, accurate modifications have been made on the single cylinder test ring and on the standard rail fuel injection system. LPG has been blended with diesel on the basis of the ratio 20-35% w/w. During the study, they have been carried out three sets of measurements: one by only using Diesel fuel and the others by using blended fuels at different engine operating conditions. The thermodynamic process, the combustion performance, and the exhaust emissions have been analyzed thanks to a specific designed-test campaign, with particular attention to the control strategies of fuel injection. The results show that, at partial load operating condition, Diesel-LPG blends improve the combustion and emission performances. In particular, it has been noticed, at constant Nitrogen Oxide (NOx), a significant decrease of particulate emissions. This observation confirms the previous authors’ results achieved on the optical engines.
Directly injecting fuel in two-stroke spark-ignition (2S-SI) engines will significantly reduce fuel short-circuiting losses. The liquid phase liquefied petroleum gas (LPG) DI (LLDI) mode has not been studied on 2S-SI engines even though this fuel is widely used for transportation. In this experimental work a 2S-SI gasoline-powered engine used on three-wheelers was modified to operate in LLDI mode with an electronic engine controller. The influences of injection pressure (IP), end of injection (EOI) timing, location of the spark plug, and type of injector on performance, combustion, and emissions were studied at different operating conditions. EOI close to bottom dead center with the spark plug located near the exhaust port was the most suitable for the LLDI mode which significantly enhanced the fuel trapping efficiency and improved the thermal efficiency. At 70% throttle condition the brake thermal efficiency increased from 19% to 25.6% and there was an 87% reduction in hydrocarbon (HC) emission compared to liquid phase LPG manifold injection. The use of multi-hole injector extended the maximum power output due to better in-cylinder mixture formation, whereas the single-hole injector extended the lean operating limit. LLDI has potential to improve the performance of small two-stroke engines significantly.
Since 1st September 2014 the Hong Kong Environmental Protection Department (HKEPD) has been utilising a Dual Remote Sensing technique to monitor the emissions from gasoline and liquified petroleum gas (LPG) vehicles for identifying high emitting vehicles running on road. Remote sensing measures and determines volume ratios of the emission gases of HC, CO and NO against CO2, which are used for determining if a vehicle is a high emitter. Characterisation of each emission gas is shown and its potential to identify a high emitter is established. The data covers a total of about 2,200,000 LPG vehicle emission measurements taken from 14 different remote sensing units. It was collected from 6th January 2012 to 20th April 2017 across a period before and after the launch of the Remote Sensing programme for evaluating the performance of the programme. The results show that the HKEPD Remote Sensing programme is very effective to detect high emitting vehicles and reduce on-road vehicle emissions. The average measured remote sensing emissions of HC, CO and NO reduced by 53.6%, 29.6% and 50.3% respectively from 2013 (the year before the launch of the programme) to 2015 (the year after the launch of the programme).
A previous system study identified significant increases in range and number of urban air mobility (UAM) missions by replacing the all battery power system of a notional UAM vehicle with an advanced diesel hybrid using conventional diesel or liquid natural gas (LNG) fuels (at constant vehicle design gross weight). Some benefits were realized using the LNG's cryogenic properties to reduce some electrical component losses and cooling requirements. Significant questions were raised concerning volume and thermal management considerations for all studied systems. The notional, baseline vehicle was a hybrid helicopter/ airplane design capable of vertical take-off and landing (VTOL), balancing high cruise efficiency with reasonable hover capability. A subsequent power system assessment using the same notional vehicle and mission was performed that identified increased volume and power requirements for the active cooling required. The cooling airflow could also generate additional drag on the vehicle during operation. For the notional vehicle studied, the additional volume identified by the subsequent study would not affect vehicle mold line and therefore drag. However, the additional drag from cooling airflow and the power to circulate it as needed would impact power system and vehicle mission performance. Vehicle and mission models were updated and rerun. Updated results still indicated significant benefits in range and number of UAM missions, but reduced the benefit by 12-15%. Hold time for the hybrid systems also generally increased a few minutes because of reduced power available for charging from the power for required cooling flows. Vehicle weights, thermal loads, and cooling airflows from the updated analyses were similar to previous results.
This paper presents the results of a two-phase Philippine study to determine the actual mileage (km/liter) of in-use diesel and LPG (liquefied petroleum gas or Auto-LPG) public utility jeepneys plying two separate Metro Manila urban routes using both on-road and chassis dynamometer tests. Measured average load factor in on-road tests was 60-70%. Dynamometer tests at 100% load factor utilized drive cycles derived from on-road speed data. A “diesel equivalent mileage” of actual LPG mileage, deemed indicative of LPG “fuel energy conversion efficiency” relative to diesel, was calculated (based solely on fuel heating values and densities) for comparing actual mileage from both fuels. The LPG actual mileage in both on-road and laboratory tests was lower than diesel mileage. In on-road tests, the LPG actual mileage was lower than diesel actual mileage by about the same percentage LPG heating value was lower than diesel’s per liter of fuel. The LPG diesel equivalent mileage was also about the same as diesel actual mileage so that fuel conversion efficiencies of both jeepney types were deemed similar. In chassis dynamometer tests at 100% load factor, the LPG diesel equivalent mileage was lower than diesel actual mileage. This implied that in addition to the effect of lesser LPG heating value per liter, the LPG jeepneys had lower energy conversion efficiencies than diesel at load factors higher than experienced in the on-road tests. Optimization of the LPG jeepney via tuning and/or powertrain configuration is suggested especially if deployed at higher load factors. The amount of financial incentives, e.g. fuel pricing, to promote LPG jeepneys should take into account its comparable on-road fuel conversion efficiency to diesel and generally accepted better emissions.
As of today, most transport vehicles use petroleum-based fuels. Although there are alternative-fueled technology demonstrators such as the Mahindra E2O or Tesla battery-electric models currently available, it will take time for these alternatives to compete with petroleum-based fuels and achieve commercial acceptance. A selection of various transport vehicles and the fuels typically used to power them: Cars and motorcycles/scooters: gasoline, diesel, CNG, LPG, battery-electric Commercial trucks: diesel Buses: diesel, CNG, battery-electric Rail: electricity, diesel, coal Small aircraft with reciprocating-engines: gasoline or Avgas Larger aircraft with turbine engines: jet fuel or kerosene
Isuzu Motors America used the ConExpo-Con/Agg 2017 stage to announce its intention to produce a dual-fuel capable (natural gas and propane) off-highway engine by mid-2018, leveraging its already-in-production on-highway CNG truck engine. The 4.6-L 4HV1 engine, on display for the first time at the Las Vegas event, will have an expected maximum rated output of 81 hp (60.5 kW) at 1800 rpm and torque rating of 247 lb·ft (335 N·m) at 1400 rpm when operating in natural gas mode.
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