Browse Topic: Liquefied petroleum gas

Items (116)

Aging of a Multi-Hole Diesel Injector and Its Effect on the Rate of Injection

2020-01-08294/14/2020

In order to comply with the increasingly restrictive limits of emissions and fuel consumption, researches are focusing on improving the efficiency of combustion engines. In this area, the aging of the injector and its effect on the injection development is not entirely analyzed. In this work, the rate of injection of a diesel injector at different stages of its lifetime is analyzed. To this end, a multi-hole piezoelectric injector was employed, comparing the injection rate measured at the beginning of its lifetime to the rate provided by the injector after aging, maintaining the same boundary conditions in both measurements. Injection pressures up to 200 MPa were used throughout the experiments. The results showed that the steady-state rate of injection was lower after the injector aged. Furthermore, the injector took a longer time to close the needle and end the injection, in comparison with the measurements done at earlier stages of its lifetime. To explain this phenomenon, measurements of momentum flux for each injector hole were done, and results showed that two holes were partially obstructed. Thus, the presence of coking in the nozzle of the injector was considered as the cause of the differences between stages seen in the rate of injection. In this sense, a reduction of the effective outlet holes area due to deposits would restrict the flow rate. Moreover, the pressure in the nozzle due to the contained fuel is extended, leading to a longer time required by the needle to descend and end the injection. Then, aging of the injector was attributed to deposits in the nozzle holes. This phenomenon could result in an inhomogeneous spray distribution, which should be taken into account when designing the combustion process.

Payri, Raul, Salvador, Francisco Javier, Gimeno, Jaime, Montiel, Tomas

Mazda details electrification strategy, confirms rotary engine's return

18AUTP11_0611/1/2018

In an announcement from Japan in October, Mazda-one of the few established automakers to articulate a comprehensive longterm commitment to hybridization or all-electric vehicle propulsion-said it intends to incorporate some type of electrification in all its vehicles by 2030. Yet in nearly the same virtual breath, the company affirmed its connection to “soulful” forms of internal combustion, including a confirmation that it will renew its longstanding enthusiasm for the rotary engine. In a carefully-worded statement, Mazda reminded that many credible forecasts call for internal combustion to remain the dominant light-vehicle propulsion source for perhaps decades to come, while discretely laying out its plan for electrification-when and where it makes sense for the environment.

Visnic, Bill

Using Liquid Natural Gas Fuel to Cryogenically Cool and Enhance a Hybrid Electric Aircraft Power System

F-0074-2018-12672

5/14/2018

ABSTRACT 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.

Snyder, Christopher, Kohlman, Lee

Realizing Stoichiometric, Natural Gas-Fueled Combustion in Diesel Engines

2018-01-11484/3/2018

For high-load applications, natural gas represents a clean burning, readily available, and relatively inexpensive alternative to number 2 Diesel fuel. However, the fuel’s poor ignitability has previously limited implementation to spark ignited and dual-fueled engines. These approaches suffer from reduced peak load and high engine-out particulate emissions, respectively, requiring lean operation and expensive aftertreatment to meet regulatory standards. A high-temperature combustion strategy can overcome the difficult ignitibility, allowing for true Diesel-style combustion of pure methane-the least ignitable and least sooting component of natural gas. In order to achieve this result, a compression system was designed to supply fuel at pressures suitably high to achieve good mixing and short injection durations, and a solenoid-actuated Diesel fuel injector was modified to function at these pressures with a gaseous fuel. This fuel supply system was paired with a single-cylinder research engine equipped with an insulated piston face. An intake preheat temperature of 250 °C was shown to provide the best combination of ignition delay and engine performance. A sweep of equivalence ratio then demonstrated soot emissions close to or below the current regulatory limit and combustion efficiencies greater than 96% up to stoichiometric fuel loadings. However, both soot emissions and combustion efficiency were worse than expected at low fuel loadings, and cycle-to-cycle variability was high throughout. Schlieren imaging and numerical investigation of the injection process demonstrate oscillatory dynamics and poor control over the end of injection. This indicates that further improvements to performance and emissions could be made by developing purpose-built gaseous fuel injectors. However, even with coarse control over injection, the improvements in particulate emissions over number 2 Diesel fuel and potential for stoichiometric operation-enabling NOx control using a three-way catalyst-make a strong case for further investigation and refinement.

Oliver, Nathaniel, Edwards, Chris

Flexible, Gravity-Fed Heat Pipe

TBMG-285443/1/2018

The advent of cryocooler technology ushers in an era where a cryogenic environment is created and maintained locally. It is no longer necessary to transport cryogen from a factory where it is produced to the location where it is needed. One problem remains for cooling large cryogenic systems with cryocoolers that extract more than 50 W of power. Although high-capacity cryocoolers are available from several commercial sources, the thermal link for connecting the cryocooler to a large system is not yet available. For small systems requiring less heat extraction, flexible heat straps made of braided copper wires are available for the thermal link. For heat extraction of more than 50 W at −100 K, this type of heat strap cannot be made short enough and flexible enough.

Powertrain mix for CVs in Europe set to diversify, but cost is critical

18TOFHP02_102/1/2018

The European Commission looks set to continue its move away from diesel, prompting manufacturers to assess future powertrain options for commercial vehicles. As many cities across Europe call for improved air quality, the Commission has proposed new targets for EU fleet-wide average CO2 emissions of new passenger cars and vans. Under its second Mobility Package proposal, average CO2 emissions from cars and vans would be cut by 15% by 2025 and should be 30% lower in 2030, compared to current plans for 2021.

Gilkes, Dan

Cryogenic and Non-Cryogenic Liquid Level Instrument

TBMG-281851/1/2018

NASA’s Marshall Space Flight Center has developed a unique prototype for measuring the liquid level in a tank, employing a novel process. The technology can operate in a wide range of environments, including high and low temperatures and pressures, and is simpler and less expensive than other optical sensing techniques. The instrument also provides far greater accuracy and faster results in cryogenic conditions than typical cryogenic liquid metering methods. It is ideal for cryogenic and non-cryogenic ground tank metering applications, and zero-gravity systems that include stratification or settling techniques.

Effects of Low Temperature Combustion on Particle and Gaseous Emission of a Dual Fuel Light Duty Engine

2017-24-00819/4/2017

In recent years the use of alternative fuels for internal combustion engines has had a strong push coming from both technical and economic-environmental aspects. Among these, gaseous fuels such as liquefied petroleum gas and natural gas have occupied a segment no longer negligible in the automotive industry, thanks to their adaptability, anti-knock capacity, lower toxicity of pollutants, reduced CO2 emissions and cost effectiveness. On the other hand, diesel engines still represent the reference category among the internal combustion engines in terms of fuel consumptions. The possibility offered by the dual fuel systems, to combine the efficiency and performance of a diesel engine with the environmental advantages of gaseous fuels, has been long investigated. However the simple replacement of diesel fuel with natural gas does not allow to optimize the performance of the engine due to the high THC emissions particularly at lower loads. Increasing the injection timing of pilot diesel fuel helps to reduce THC, but cause an increase of the nitrogen oxides. Therefore more complex combustion strategies should be realized to meet vehicles emission standards. In this paper, the benefits obtainable through the activation of the low combustion temperatures have been evaluated. LTC can be activated by means of very early diesel injection timings and with the maximum by natural gas share tolerable for stable combustion. The experimental activity was also focused to analyze the particle emissions which, as is well known, represent together with the nitrogen oxide emissions, the main pollutants resulting from the combustion of diesel fuel. The activation of LTC has shown the potential to simultaneously reduce both THC and NOx emissions as well as ensuring ultra-low particle emissions. Therefore LTC should be considered as a key-strategy to make DF engines compliant with the limits imposed for the vehicles approval.

De Simio, Luigi, Gambino, Michele, Iannaccone, Sabato

Potential and Challenges of HPDI

2017-01-19285/10/2017

Globally, many jurisdictions are working toward greenhouse gas (GHG) emissions standards for medium- and heavy-duty vehicles that will take effect in the next decade and require GHG reductions of up to 25% from 2017 legislated levels. While diesel engines will require increasingly complex improvements, high pressure direct injection (HPDI) of natural gas can provide GHG reductions of approximately 20% (75% or more with renewable natural gas / bio-methane) while preserving the same power density, torque and performance as diesel. This paper will provide an overview of the improvements in the Westport™ HPDI 2.0 components as well as performance and emissions results demonstrated to-date. The potential and challenges of higher injection pressures will be explored while also investigating sources of and methods to eliminate methane venting on the vehicle.

Mumford, David, Goudie, Dale, Saunders, James

Future Specification of Automotive LPG Fuels for Modern Turbocharged DI SI Engines with Today’s High Pressure Fuel Pumps

2016-01-225510/17/2016

Liquefied Petroleum Gas direct injection (LPG DI) is believed to be the key enabler for the adaption of modern downsized gasoline engines to the usage of LPG, since LPG DI avoids the significant low end torque drop, which goes along with the application of conventional LPG port fuel injection systems to downsized gasoline DI engines, and provides higher combustion efficiencies. However, especially the high vapor pressure of C3 hydrocarbons can result in hot fuel handling issues as evaporation or even in reaching the supercritical state of LPG upstream or inside the high pressure pump (HPP). This is particularly critical under hot soak conditions. As a result of a rapid fuel density drop close to the supercritical point, the HPP is not able to keep the rail pressure constant and the engine stalls. Thus, in order to enable wider use of LPG and to assist the process of standardization, a limitation for maximum content of C3 fuel components - as propane and propene - is required as a key enabler for LPG DI applications. In order to determine a maximum C3 limit, hot idle investigations were performed on a modern turbocharged 4-cylinder direct injection spark ignition (DI SI) engine operated in a climate cham. Furthermore, stationary idle tests were carried out on a single cylinder engine with four different LPG fuels, all in accordance with EN 589. The experimental investigations indicate a maximum content of 70 % (m/m) C3 fuel components as an upper limit for an LPG DI injection concept, when a HPP, which is based on state-of-the-art HPP technology for gasoline engines, is used. For a maximum propane content of 70 % (m/m), pump functionality can be maintained with a fuel pressure of approximately 45 bar upstream the HPP at fuel temperatures of about 110 °C during hot idle. For lower pressures upstream the HPP, cooling measures need to be implemented.

Krieck, Martin, Günther, Marco, Pischinger, Stefan, Kramer, Ulrich, Heinze, Thomas, Thewes, Matthias

Comparison of Pollutant Emissions from Common Platform Vehicles Operating on Alternative Fuels over a Range of Driving Cycles at Standard and Cold Ambient Temperatures

2016-01-221610/17/2016

Alternative fuels and power trains are expected to play an important role in reducing emissions of greenhouse gases (GHGs) and other pollutants. In this study, five light-duty vans, operating on alternative fuels and propulsion systems, were tested on a chassis dynamometer for emissions and efficiency. The vehicles were powered with Tier 2 gasoline, low blend ethanol (E10), compressed natural gas (CNG), liquefied petroleum gas (LPG), and an electric battery. Four test cycles were used representing city driving and cold-start (FTP-75), aggressive high speed driving (US06), free flow highway driving (HWFCT), and a combination of urban, rural, and motorway driving (WHVC). Tests were performed at a temperature of 22°C, with select tests at -7°C and -18°C. Exhaust emissions were measured and characterized including CO, NOX, THC, PM and CO2. On the FTP-75, WHVC, and US06 cycles additional exhaust emission characterization included N2O, and CH4. On the FTP-75, carbonyl compounds and volatile organic compounds (VOCs) were also characterized. Fuel and energy consumption, CO2,e and NMOG emissions were calculated. The emissions impact of alternative fuels varied with temperature and driving cycle. Compared to conventional gasoline, the use of alternative fuels generally resulted in reduced CO2 equivalent emission rates: 12-14% reduction with the use of LPG fuel, 18-21% reduction with the use of CNG fuel, and 60-75% reduction with the use of battery electric propulsion (assuming the average Canadian mix for electricity generation). With E10 fuel, the reductions in tailpipe CO2 equivalent emission rate were generally not statistically significant. Results for other regulated and unregulated emissions varied, and depended on driving cycle and temperature.

Richard, Brad, Christenson, Martha, Rosenblatt, Deborah, Conde, Aaron

Cryogenic Liquid Level Sensor Apparatus and Method

TBMG-25299

9/1/2016

Innovators at NASA’s Armstrong Flight Research Center have developed a highly accurate method for measuring liquid levels using optical fibers. Unlike liquid level gauges currently on the market that rely on discrete measurements to give broad approximations of liquid levels, Armstrong’s innovative fiber optic method provides precise and accurate measurements. Specifically, Armstrong’s novel method is capable of providing measurements at 1/4-inch intervals within a tank. This significant leap forward in precision and accuracy in liquid level sensing offers significant benefits to many industries. Originally designed by NASA to monitor a rocket’s cryogenic fuel levels, this technology can be used in many medical, industrial, and pharmaceutical applications.

Optical Characterization of Propane at Representative Spark Ignition, Gasoline Direct Injection Conditions

2016-01-08424/5/2016

The focus of internal combustion (IC) engine research is the improvement of fuel economy and the reduction of the tailpipe emissions of CO2 and other regulated pollutants. Promising solutions to this challenge include the use of both direct-injection (DI) and alternative fuels such as liquefied petroleum gas (LPG). This study uses Mie-scattering and schlieren imaging to resolve the liquid and vapor phases of propane and iso-octane, which serve as surrogates for LPG and gasoline respectively. These fuels are imaged in a constant volume chamber at conditions that are relevant to both naturally aspirated and boosted, gasoline direct injection (GDI) engines. It is observed that propane and iso-octane have different spray behaviors across these conditions. Iso-octane is subject to conventional spray breakup and evaporation in nearly all cases, while propane is heavily flash-boiling throughout the GDI operating map. This severe flashing behavior has major implications for the design and calibration of LPG DI injection systems and engines.

Lacey, Joshua, Poursadegh, Farzad, Brear, Michael, Petersen, Phred, Lakey, Charles, Ryan, Steve, Butcher, Brendan

An Experimental Study of the Combustion, Performance and Emission Characteristics of a CI Engine under Diesel-1-Butanol/CNG Dual Fuel Operation Mode

2016-01-07884/5/2016

In order to comply with the stringent emission regulations, many researchers have been focusing on diesel-compressed natural gas (CNG) dual fuel operation in compression ignition (CI) engines. The diesel-CNG dual fuel operation mode has the potential to reduce both the soot and NOx emissions; however, the thermal efficiency is generally lower than that of the pure diesel operation, especially under the low and medium load conditions. The current experimental work investigates the potential of using diesel-1-butanol blends as the pilot fuel to improve the engine performance and emissions. Fuel blends of B0 (pure diesel), B10 (90% diesel and 10% 1-butanol by volume) and B20 (80% diesel and 20% 1-butanol) with 70% CNG substitution were compared based on an equivalent input energy at an engine speed of 1200 RPM. The results indicated that the diesel-1-butanol pilot fuel can lead to a more homogeneous mixture due to the longer ignition delay. Using certain multiple injection strategies under medium load (a diesel equivalent load of 20 mg/cycle), the diesel-1-butanol-CNG combustion mode can significantly improve the indicated thermal efficiency (ITE). B10 showed low unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions; while B20 presented low NOx and soot emissions. The results also indicated that B20 case has the potential to obtain high ITE and low NOx and soot emissions simultaneously under low and medium load conditions.

Meng, Xiangyu, Nithyanandan, Karthik, Lee, Timothy, Li, Yuqiang, Long, Wuqiang, Lee, Chia-Fon

Vehicle Design, Battery Design and Distribution Model to Implement Battery Swapping in Battery Electric Vehicles, by Drawing Parallels with the Indian LPG-Distribution Network which has Effectively Implemented Cylinder-Swapping Methodology

2016-28-00242/1/2016

To increase the range of a Battery Electric Vehicle (BEV), a lot of ideas have been proposed. A prominent one among them is the Battery swapping methodology or Rapid Battery Interchange (RBI), where standardized batteries can easily be removed from the BEV and replaced with recharged batteries quickly. The feasibility of this methodology has been highly debated and contested. This paper studies the feasibility of a very popular distribution and maintenance network currently used for LPG distribution in India, to be applied to battery distribution used across different makes and models of BEVs. In India, 33.6 million households subscribe to LPG Cylinders for domestic cooking usage. These standard sized (14.2Kg) cylinders are refilled and redistributed via multiple public sector and private companies. The paper also focuses on another advantage that can be borrowed from this system, which is the ability of the government to subsidies this resource, allowing quick mass-outreach of the facility, aligning it with the Indian Government’s FAME (Fast Adoption and Manufacture of Electric & Hybrid Vehicles) plan. LPG distribution model also has challenges common with Battery swapping. The distributer is responsible for safety, installation, supply, maintenance and regulations. The research focuses on drawing parallels with the existing LPG Cylinder manufacture, distribution and maintenance and finds appropriate applications to a Battery Swapping network.

Rai, Aditya, Vijh, Sanchit, Sethupathi, P Baskara

An Experimental Study on Fuel Consumption and Emission Characteristics of LPG-HEV City Transit Buses

2015-01-27979/29/2015

This paper studies the characteristics of fuel consumption and exhaust emission of city transit buses, and analyzes the fuel saving rate and exhaust pollutants reduction effect of LPG-HEV buses relative to LPG buses. The running speed, fuel consumption, exhaust emission and other variables of 3 LPG-HEV buses that aren't plug-in hybrid, and 2 LPG buses were measured by a portable emission measurement system (PEMS) under real driving situations of city transit buses in Guangzhou, China. The test data was analyzed to make a comparison between LPG-HEV and LPG buses. The study results show that the running speed of city buses in real driving modes is mainly distributed in the range of 0 to 35 km/h, and the average value is 18km/h, while the acceleration is distributed in a range from −0.5 to 0.5m/s2 mainly. The average fuel consumption of LPG-HEV buses is 51.02 l/100km, and is 6.23% lower than that of LPG buses. The fuel saving effects appears when its speed below 25 km/h, and the lower the speed is, the more significant the fuel saving effect will be. The average emission factors of exhaust gases NOx, CO and HC of LPG-HEV buses are 21.7g/km, 2.36g/km and 1.61g/km, and has a change ratio of −18.9%, 108.8% and 10.3%respectively by contrast with that of LPG buses. The increase of CO and HC emission factors of LPG-HEV buses is due to the decrease of excess air coefficient in LPG-HEV engine.

Peng, Meichun, Zheng, Yue, Jiang, Xiaoyan, Wang, Jiahao

Hybrid Laminate Composite for Harsh Environments and High-Performance Applications

TBMG-22852

9/1/2015

A multi-functional composite laminate material has been developed for structural and thermal applications for use in durable cryogenic fuel tanks for transportation vehicles and/or in the construction of habitats. The technology focuses on aerogel and fiber composites integrated into unique layups with thermal and mechanical energy absorption capabilities. The lightweight laminate composite system has multi-functionality for both high- and low-temperature applications. Combining structural and thermal attributes, the innovation is a lightweight aerogel-fiber laminate composite system with good compressive strength, tailorable for impact and acoustic energy absorption, reduced heat transfer, and/or fire barrier properties.

An Experimental Study of Injection and Combustion with Dimethyl Ether

2015-01-09324/14/2015

DiMethyl Ether (DME) has been known to be an outstanding fuel for combustion in diesel cycle engines for nearly twenty years. DME has a vapour pressure of approximately 0.5MPa at ambient temperature (293K), thus it requires pressurized fuel systems to keep it in liquid state which are similar to those for Liquefied Petroleum Gas (mixtures of propane and butane). The high vapour pressure of DME permits the possibility to optimize the fuel injection characteristic of direct injection diesel engines in order to achieve a fast evaporation and mixing with the charged gas in the combustion chamber, even at moderate fuel injection pressures. To understand the interrelation between the fuel flow inside the nozzle spray holes tests were carried out using 2D optically accessed nozzles coupled with modelling approaches for the fuel flow, cavitation, evaporation and the gas dynamics of 2-phase (liquid and gas) flows. And to understand the spray characteristics tests were carried out using constant volume vessel. For a spray observation, two methods were used a shadowgraph and a diffuse forward scatter method to obtain both gaseous phase and liquid phase of DME. Tests were then run on a single cylinder engine to determine the differences in combustion with the differing hole shapes as well as extra high injection pressure. Results showed that the different nozzle hole shapes changed the flow and the cavitation tendency. And these characteristics be utilized for an optimaization of the spray and combustion

Sasaki, Satoru, Kato, Masaaki, Yokota, Takamasa, Konno, Mitsuru, Gill, Denis

A Study of Supercharged HCCI Combustion Using Blended Fuels of Propane and DME

2014-32-000511/11/2014

Homogeneous Charge Compression Ignition (HCCI) has attracted a great deal of interest as a combustion system for internal combustion engines because it achieves high efficiency and clean exhaust emissions. However, HCCI combustion has several issues that remain to be solved. For example, it is difficult to control engine operation because there is no physical means of inducing ignition. Another issue is the rapid rate of heat release because ignition of the mixture occurs simultaneously at multiple places in the cylinder. The results of previous investigations have shown that the use of a blended fuel of DME and propane was observed that the overall combustion process was delayed, with that combustion became steep when injected propane much. This study focused on expanding the region of stable engine operation and improving thermal efficiency by using supercharging and blended fuels. The purpose of using supercharging were in order to moderated combustion. In addition, the purpose of using blended gaseous fuels were find out effective use of gaseous fuels. Low-carbon gaseous fuels with clean emissions were used as the test fuels. The specific fuels used were dimethyl ether (DME, cetane number of 55 or higher) that exhibits pronounced low-temperature oxidation reactions. Propane (cetane number of 5) that does not exhibits low-temperature reaction readily and that is a principal component of liquefied petroleum gas. A spectroscopic measurement technique was used to investigate the combustion in detail by obtain the light emission spectra of the combustion flame. The characteristics of the reaction products were investigated by analyzing the exhaust gas components using Fourier transform infrared spectroscopy. The results shows that the quantity of DME and propane ratio injected determines the ignition timing, the engine load level can be adjusted by means of the quantity of propane injected to achieve ignition near top dead center. In addition, combustion became moderate by supercharging.

Mochizuki, Keisuke, Shima, Takahiro, Suzuki, Hirotaka, Ishikawa, Yoshihiro, Iijima, Akira, Yoshida, Koji, Shoji, Hideo

The Effect of the LPG Injector Distance from an Inlet Valve on the Combustion Process in a SI Engine

2014-01-262410/13/2014

This paper seeks to examine the effect of distance of the gas injector from an inlet valve on the combustion process in a LPG fuelled SI engine under varied injection timing. Tests were conducted at an engine test stand, where the operating conditions of the engine were maintained stable. The tests were undertaken on an indirect injection spark ignition engine under partial load and at a constant speed. Holes in the inlet pipes were drilled in order to test for four variants of injection nozzle distance from the combustion chamber into which 4 mm diameter nozzles were successively mounted. Each given distance was measured along the symmetry axis of the inlet port, which represents a real path of the fuel-air mixture. The results show that the engine performance is affected more by the injector distance from the inlet valve than by varied LPG injection timing. Consequently, cycle-to-cycle variations of main combustion parameters and engine performance parameters were analyzed. The results show that the distance between the injection nozzle and the combustion chamber affects the unrepeatability of engine operation. To evaluate the cycle-to-cycle variations of the combustion parameters, the coefficient of variation (COV) and return maps of the IMEP were calculated for each engine operating condition. The increase of CO and HC emission were recorded in some cases because of the nozzle distance impact on combustion. The maximum distance between the nozzle and the inlet valve caused a significant increase of hydrocarbon in exhaust gases.

Grabowski, Lukasz

Emission and Performance Enhancement of Multi-Cylinder SI Engine Fuelled with LPG and Vaporized Water Methanol Induction

2014-01-276410/13/2014

This work aims study on the method of NOx reduction and performance enhancement by analysis of MPFI multi-cylinder gasoline engine running on LPG using the gas injection system and vaporized water-methanol induction to the intake manifold. For the generation of vaporized water-methanol, heat from the exhaust gas has been used. Different percentages of water- methanol by mass basis were used with variable engine speed ranging from 2000 to 4500 RPM. The outcomes indicated that as the percentage water-methanol induction level of the engine increased, there is a slight increase in percentage of useful work, while the NOx decreased drastically about 47%. Additionally, the engine brake thermal efficiency gains. The mean gain in the brake thermal efficiency for a 20% water methanol with LPG is approximately 1.5% over the use of LPG without water-methanol induction.

Patil, Bhimrao, Nayak, Vighnesha, Padmanabha, Mohanan

Model-Based Control for Air-Fuel Ratio of Natural Gas Fueled SI Engines

2014-01-258510/13/2014

This paper proposes a fast and simple model of a Compressed Natural Gas indirect injection system to predict the system dynamics with high accuracy for different operating conditions. In a retrofit system the CNG Engine Control Unit (ECU) is able to translate the petrol ECU control strategy in CNG operation. The adaptation of the engine to the natural gas type is handled by using the factory engine control strategy embodied in the factory ECU. The ECU monitors the engine through various sensors and controls its operation using a variety of actuators. Because of many input parameters, the control over the engine becomes quite complex. The use of advanced emission control systems makes such process even more complicated. The new Gas Control Unit is used to reprogram the ECU control parameters to correspond with the use of Natural Gas along with the characteristics of the Natural Gas injectors. Since gaseous fuels are not affected by evaporation effects, the intake fuel-air mixing transfer function has very little dynamic effects. The control system has been tested on a set of Air-Fuel ratio dynamic transients measured on a commercial engine, showing good accuracy in predicting the Air/Fuel ratio. Experimental results on an actual engine show high effectiveness of the presented method.

Wendeker, Miroslaw, Baranski, Grzegorz, Magryta, Pawel

Liquid State LPG Conversion of an Older Vehicle

2014-01-261310/13/2014

A conversion to LPG of a SI engine that was originally carbureted gasoline is reported in this work. The conversion was implemented on a 1988 Skoda 120L with a 1174cc rear engine. The conversion to run on Liquefied Petroleum Gas (LPG) was carried out using a programmable Engine Control Unit (ECU) that operated a single point fuel injection system. The LPG used was a commercially available mixture of butane and propane. The fuel injection system was designed to operate with the LPG in the liquid state. A circulating pump was used to maintain availability of LPG in liquid state at the inlet to the fuel injector. This made possible the use of similar fuel injection parts as in a gasoline system. Injection of the fuel in the liquid state provided cooling to the intake air as measured during driving of the vehicle and also on chassis dynamometer runs. Engine power output measured on the chassis dynamometer showed equal power between gasoline and LPG around mid RPM of 2500 RPM with a slight decline (4%) in power of the LPG system at 5000 RPM. The conversion was so designed such that the vehicle could cold start on LPG. However the engine could also be reverted to run on gasoline by the changeover of an electrical switch. The dual fuel strategy was adopted due to the fact that the LPG storage container used was relatively small compared to the size of the gasoline tank.

Farrugia, Mario, Briffa, Andrew, Farrugia, Michael

A Detailed Analysis of Proper Safety Features Implementation in the Design and Construction of Modern Automotive LPG and CNG Containers

2014-01-04184/1/2014

Paper describes analysis of the design process of modern automotive LPG and CNG containers. Over decade experience in the field of both computer based analysis as well as in the real conditions testing has been collected and presented in the paper. Authors present the potentials of modern FEM methodologies in the optimization and production of lightweight steel containers. It has been proved that the most sophisticated numerical analysis have to be followed by the construction verification, particularly considering direct exposure to fire. Bonfire test have become obligatory for both liquid and compressed gases containers. Properly chosen fire protection system, together with the adequate level of quality of materials applied for its production together with proper directing of the gas flowing out from safety devices are the essential factors defining gas containers fire safety. The experience in the field of bonfire tests made it also possible to present the main issues of the proper couplings of containers with their equipment (valves). Many analyzed cases made it possible to provide interesting illustrations presenting validation of the container design in the real conditions during both burst and bonfire tests.

Flekiewicz, Bartosz, Flekiewicz, Marek

Comparison of Life Cycle Greenhouse Gas Emissions of Conventional, CNG-Hybrid and Electric Powertrains for Long Mileage Application in a Taxi for Singapore

2014-01-16164/1/2014

In this analysis we assess the life cycle greenhouse gas (GHG) emissions of four types of vehicles which might play a role in achieving future emission reductions: vehicles using compressed natural gas (CNG), battery electric vehicles (BEVs), mild hybrid CNG vehicles and range extended BEVs. Our analysis covers the manufacturing processes of these vehicles and their use as a city taxi in Singapore. We also consider upstream emissions from fuel and electricity production. All necessary parameters are derived from an intensive literature review and the model for calculating the life cycle emissions is presented. The influence of data uncertainties is analyzed by parameter variations within different scenarios. The calculation results are found to be quite robust: The BEV and the mild hybrid CNG vehicle similarly show very low GHG emissions within all scenarios whereas the pure CNG vehicle always ranks the worst. In an additional scenario we also assessed the influence of an improved electricity generation with lower emissions in the future. In this the results of the BEV and the range extended BEV were significantly improved compared to the previous baseline calculations. We conclude that the introduction of BEVs is an effective measure to reduce GHG emissions in the transport sector of the future. However, mild hybrid CNG vehicles seem to be a very practicable solution for mobility with less GHG emissions today and in the nearer future.

Reuter, Benjamin, Gleyzes, Daniel, Lienkamp, Markus

Design and Analysis of a Modified CFR Engine for the Octane Rating of Liquefied Petroleum Gases (LPG)

2014-01-14744/1/2014

This paper presents a combined experimental and numerical study of a modified Cooperative Fuel Research (CFR) engine that allows both the Research and Motor octane numbers (RON and MON) of any arbitrary Liquefied Petroleum Gas (LPG) mixture to be determined. The design of the modified engine incorporates modern hardware that enables accurate metering of different LPG mixtures, together with measurement of the in-cylinder pressure, the air-fuel ratio and the engine-out emissions. The modified CFR engine is first used to measure the octane numbers of different LPG mixtures. The measured octane numbers are shown to be similar to the limited data acquired using the now withdrawn Motor (LP) test method (ASTM D2623). The volumetric efficiency, engine-out emissions and combustion efficiency for twelve alternative LPG mixtures are then compared with equivalent data acquired with the standard CFR engine operating on a liquid fuel. Finally, the modified CFR engine is modelled using GT-Power. The full engine model contains empirical sub-models of the intake and exhaust systems, the gas exchange processes, the flame propagation and the in-cylinder heat transfer. The calibrated combustion models are used to determine the residual gas fraction and crank angle resolved mass fraction burned histories during octane rating for both gaseous and liquid fuels. Overall, this analysis suggests that the performance of the modified CFR engine is consistent with that of the standard engine operating on a conventional, liquid fuel.

Morganti, Kai, Foong, Tien Mun, Brear, Michael, Da Silva, Gabriel, Yang, Yi, Dryer, Frederick

Effect of Injection Timing Retard on ISI Strategy in Lean-burning LPG Direct Injection Engines

2013-01-263610/14/2013

Because of the concerns regarding global warming caused by greenhouse gases and the high cost of fossil fuels, research on improving the fuel economy and emissions in internal combustion engines has become important. Specifically for spark ignition engines, lean-burning direct injection is the most promising technology because the fuel economy and emissions can be improved using a stable combustion of a stratified mixture. This study aimed to develop a spray-guided, lean-burning liquefied petroleum gas (LPG) direct injection engine through optimizing the combustion parameter controls. In previous research, the brake thermal efficiency in an LPG direct injection engine was significantly increased and stable combustion was secured with an interinjection spark ignition (ISI) strategy under low-load operating conditions. However, the simple application of an ISI strategy does not improve the combustion stability under relatively high-load operating conditions, and consequently, the extent of specific fuel consumption reduction is small. In the present study, the effect of injection timing on the combustion stability was assessed and the fuel economy and emission characteristics were compared. Retarding the 2nd injection timing of the ISI strategy effectively improved combustion stability, but it did not reduce the fuel consumption.

Park, Cheolwoong, Park, Yunseo, Oh, Seungmook, Lee, Yonggyu, Kim, Tae Young

DUAL FUEL - Potential of Combined Combustion of CNG and Diesel Fuel

2013-36-013310/7/2013

The continuous increase in the price of diesel fuel, the longer availability of CNG and the potential to reduce CO2 enhances the attractiveness to replace diesel fuel by CNG, especially in the aspiring economic markets. One possibility of this is the portrayal of Dual Fuel operation, using a conventional diesel engine with minor modifications, which can be operated either in diesel or a Dual Fuel (gas/diesel) mode. In this combustion mode, it must be possible to obtain a diesel substitution rate up to a maximum of 90 % and 70% on average, as the actual work indicates. In order to illustrate the potential of such a concept, tests were carried out on a 4 cylinder, 7 litre commercial vehicle engine, which was equipped for external carburation using commercial CNG components, as well as a development control unit with software functionality designed in-house. The objective of the investigations is the calibration of the engine for Dual Fuel operation by optimizing the injection and combustion parameters to comply with EU6 emission regulations, under stationary and transient conditions. The difficult conversion of methane, which only takes place at comparatively high temperatures, is the biggest technical challenge. Energetically, the concept represents a bridging technology to pure CNG operation and can contribute to the quicker development of the CNG infrastructure.

Doppelbauer, C., Penz, Mario, Renner, Daniel, Masser, Karl, Dorfer, F.

Dual Fuel Engine - Diesel and Compressed Natural Gas Engine and After Treatment System

2013-36-049010/7/2013

With the discovery of oil and gas in the pre-salt Santos and Campos basin, the supply of natural gas (NG) is expected to increase considerably, so the use of compressed natural gas (CNG) in city buses will be an important option for reducing the overall consumption of fossil diesel fuel and a reduction in operating costs in São Paulo and Rio de Janeiro Metropolitan Areas in Brazil. A vehicle with an engine that can run on pure diesel or diesel and CNG has advantage over a vehicle that works exclusively with CNG, because when there is no availability or the lack of CNG, the vehicle / engine operates with diesel only. Another benefit of this technology is the resale value in Brazil, because after the life cycle of use in theses two big cities, Urban Buses are sold country side to small cities where CNG is not available. Another great advantage of this system is its robustness and non-dependence of spark ignition and coils, because the combustion will begin with pilot injection of Diesel. The use of CNG with 90% of substitution ratio will provide a reduction of up to 19% in CO2 emissions (GHG - Greenhouse gas). The Dual fuel engine has the same performance and load response than Diesel engine, with slightly lower efficiency, emitted lower CO2, PM and higher CH4. CH4 is the concern, but the balance of CO2 equivalent (GHG) is better 47,5 g/kWh than Diesel only version. If the availability of Natural Gas and Biomethane increase and the price of CNG and Diesel keep in today baseline in one year, one bus will save R$ 7.978,00 or U$ 4.000,00 and the interest in dual fuel engine will grow.

Shiraiwa, Nilton Mitsuro, Mozardo, Rodrigo, da Costa, Celso Macarini, Muraro, Wilson, Lemcke, Thomas, Zambotti, Aníbal

How to Make Your Fleet More Sustainable and Save Money: The Ford Fleet Purchase Planner

2013-01-05064/8/2013

Ford's portfolio approach to sustainable mobility offers a large range of fuel-efficient engines and alternative-fuel vehicles - including EcoBoost®, hybrid, plug-in hybrid, flexible fuel, battery-electric, B20 biodiesel and compressed natural gas or liquefied petroleum gas (CNG/LPG) vehicles. The Ford Fleet Purchase Planner has been developed to assist fleet customers in comparing these alternatives and understanding which vehicles offer the optimal mix to achieve CO₂ emission reductions while balancing corporate financial goals. Vehicle fleets for large corporations can have thousands of vehicles that are replaced on a timescale of months to years. We present the three main components of the Fleet Purchase Planner (patent pending) that provide fleet customers the lowest cost solution to achieving their sustainability goals: the Vehicle Emissions & Fuel Cost Calculator, the Fleet CO₂ Emissions Footprint Status Calculator, and the Purchase Recommender. The Vehicle Emissions & Fuel Cost Calculator applies customer-specific information, such as vehicle type, fuel type and price, driving conditions (city or highway), geographic region where the vehicle will operate, and fuel efficiency to generate the vehicle sustainability and fuel cost information. The Fleet CO₂ Emissions Footprint Status Calculator is designed to help fleet customers understand their current carbon footprint based on their specific fleet, regions, and fuel economy. The Purchase Recommender uses mathematical optimization to provide customized purchase recommendations that highlight the best value opportunities for improving corporate sustainability. This innovative analytical solution helps Ford fleet customers better understand their green vehicle technology options and identify the optimal vehicle fleet for their needs.

Winkler, Sandra, Reich, Daniel, Klampfl, Erica, Wallington, Timothy

Emission Characteristics of Gasoline and LPG in a Spray-Guided-Type Direct Injection Engine

2013-01-13234/8/2013

Nowadays, automobile manufacturers are focusing on reducing exhaust-gas emissions because of their harmful effects on humans and the environment, such as global warming due to greenhouse gases. Direct injection combustion is a promising technology that can significantly improve fuel economy compared to conventional port fuel injection spark ignition engines. However, previous studies indicate that relatively high levels of nitrogen oxide (NOx) emission were produced with gasoline fuel in a spray-guided-type combustion system as a result of the stratified combustion characteristics. Because a lean-burn engine cannot employ a three-way catalyst, NOx emissions can be an obstacle to commercializing a lean-burn direct injection engine. Liquefied petroleum gas (LPG) fuel was proposed as an alternative for reducing NOx emission because it has a higher vapor pressure than gasoline and decreases the local rich mixture region as a result of an improved mixing process. The combustion and emission characteristics of LPG and gasoline fuels were compared in a multi-cylinder engine with a spray-guided-type combustion system. A lower NOx emission value could be achieved with a single injection of LPG, while the hydrocarbon emissions increased.

Park, Cheolwoong, Park, Yunseo, Oh, Seungmook, Lee, Yonggyu, Kim, Tae Young, Kim, Hongsuk, Choi, Young, Kang, Kern-Yong

Using Mix of Gasoline and Liquefied Petroleum Gas for Lower Emissions and Greater Torque

2013-01-11514/8/2013

The paper considers the problem of how to improve the economic efficiency of gasoline-powered internal combustion (IC) engines and at the same time increase their eco-friendliness and reduce emissions. Current industry thinking is that the use of alternative fuels (e.g. liquefied petroleum gas (LPG), which is widely used) helps reduce emissions of harmful substances in exhaust gases, but causes a reduction in engine power and torque. One of the ways to fix this problem is to add gasoline to the LPG, while current approaches to this problem improve either ecological performance or power readings of engines. It is assumed that one can change the fuel burning velocity and the amount of harmful substances in exhaust gases by adding gasoline to LPG and varying their percentage fuel mixture (called binary), thus providing higher ecological and operating performance of IC engines. Based on the above assumption a new engine control method has been developed, which improves gasoline IC engine performance and reduces emissions by adjusting the binary fuel composition and controlling the ignition advance angle. The paper presents the results of the experiments set up and examines the efficiency of the method developed.

Beresnev, Max, Beresnev, Alex

Fuel Effect on Particle Emissions of a Direct Injection Engine

2013-01-15594/8/2013

PN emissions were measured using a 2012 1.6L gasoline direct injection (GDI) engine vehicle. The measurements were performed over NEDC using domestic fuel from South Korea and Euro 5 certification fuel, also FTP-75 cycle using domestic fuel and Indolene (official emission test fuel in the US). Domestic fuel is the most volatile and has the least aromatics, Euro 5 certification fuel is the least volatile and has the most aromatics. Lower volatile gasoline generates more particle emissions due to diffusion combustion of fuel attached on the piston and fuel residues which are burned in its liquid form. Gasoline with more aromatic contents generates more particle emissions, too. Because aromatics have higher boiling point, lower vapor pressure and ring structures. Fuel specification difference resulted in PN emission difference. In NEDC tests, result using Euro 5 certification fuel was 77.0% higher than the result using domestic fuel. In FTP-75 cycle tests, Indolene resulted in 20.8% higher than domestic fuel. Mode tests using LPG were performed via the same vehicle. PN results using LPG over NEDC and FTP-75 cycle were 3 orders lower than the results from gasoline tests. This is due to high volatility of LPG. From the test results, it is confirmed that PN emissions from the DI engine are significantly affected by fuel characteristics. Even if PN regulation is satisfied with one fuel, there is no guarantee that is satisfied with other fuels. But for the LPG direct injection engines, PN regulation could not be a problem.

Kim, Yongha, Kim, Youngjae, Kang, Jiwon, Jun, SangYoul, Rew, SeungHyun, Lee, Donghyeon, Park, Simsoo

A Numerical Investigation of Mixing Characteristics of a Direct-Injection (DI) Engine with Liquefied Petroleum Gas

2013-01-01363/25/2013

Mixing characteristics of a Direct-Injection engine with liquefied petroleum gas were numerically investigated using a 3D unsteady Eularian-Lagrangian two-phase model. Numerical results were validated to the experimental data of heat release rate, pressure and mass flow rate of air. The numerical results and experimental data were in a good agreement. Simulations were conducted with various engine operation conditions to investigate the effects of supercharging on the mixing characteristics of the DI engine with LPG. The results showed that the fuel uniformities and evaporation rates of LPG are higher than them of gasoline. Fuel consumption rates and maximum cylinder temperatures of LPG were also higher than them of gasoline.

Lee, Jae Seong, Seo, Juhyeong, Kim, Ho Young, Park, Simsoo

Design of Retrofit Kit for LPG Driven Direct Injection Two-Stroke Engines

2012-32-011710/23/2012

Two-stroke engines are common for small transportation units in many South Asia countries. Due to high fuel losses during the scavenging process the pollution emitted by these two stroke vehicles is significant. In this paper, we investigate the details of a gaseous fuel direct injection system using liquid petroleum gas (LPG). A series of three-dimensional, computational fluid dynamic (CFD) simulations are run on various injection geometries, evaluating the air/fuel mixing of the resulting in cylinder charge. The results of the simulations indicate the best injector placement based on air fuel mixing and the best location to install the spark plug.

Tan, Yee Hern, Gitano, Horizon

Influence of Different Natural Gas Blends on the Regulated Emissions, Particle Number and Size Distribution Emissions from a Refuse Hauler Truck

2012-01-15839/10/2012

Natural gas is a potential alternative to conventional liquid fuels for use in automotive internal combustion engines. The primary goal of this study is to understand how gas composition changes might impact the performance or emissions of a natural gas vehicle or engine. For this study, a waste hauler truck equipped with a 2001 Cummins 8.3L C Gas Plus lean burn spark-ignited engine and an oxidation catalyst was operated on the William H. Martin Refuse Truck Cycle (RTC). This cycle was developed to simulate waste hauler operation and consists of a transport segment, a curbside pickup segment, and a compaction segment. The vehicle was tested on 7 different gases including two gases representative of Texas and Rocky Mountain Pipeline Gases, a Peruvian LNG, a Middle East LNG-Untreated with high Wobbe number (above 1400), two gases representative of those located within the state that have low methane number (MN) as well as varying hydrocarbon compositions, and a CNG blend produced from an LNG fuel tank with similar properties to the first two gases. The experimental results indicate the fuel composition had a noticeable effect on fuel economy and carbon dioxide (CO₂) emissions of the waste hauler, with the high energy content and higher hydrocarbons gases exhibiting higher fuel economy and CO₂ emissions. Emissions of nitrogen oxides (NO ) were also influenced by fuel composition, and increased for gases with higher levels of heavier hydrocarbons. Total hydrocarbon (THC), nonmethane hydrocarbon (NMHC), and methane (CH₄) emissions were affected by the concentration of higher hydrocarbon molecules in the gases, with gases with higher levels of CH₄ showing high THC and CH₄ emissions and lower NMHC emissions. Decreases in particulate matter mass, particle number, and, in some cases, CO emissions were also found for the gases with more heavy hydrocarbons, while fuel quality had a minimal impact on particle size distributions.

Karavalakis, George, Hajbabaei, Maryam, Durbin, Thomas, Zheng, Zhongqing, Johnson, Kent

Performance and Emission Analysis of a Single Cylinder Constant Speed Diesel Engine Fuelled with Diesel-Methanol-Isopropyl Alcohol Blends

2012-01-16839/10/2012

Performance of a compression ignition engine fuelled with Diesel Methanol blends with Isopropyl alcohol is evaluated. A single-cylinder, air-cooled, direct injection diesel engine developing a power output of 5.2 kW at 1500 rev/min is used. Base data is generated with standard diesel fuel, four fuel blends namely 80:10:10, 70:20:10, 60:20:20 and 50:30;20 percentages by volume of diesel, methanol and isopropyl alcohol were prepared and tested in the diesel engine. Engine performance and emission data were used to optimize the blends for reducing emission and improving performance. Results show improved performance with blends compared to neat fuel. However, 60:20:20 blends recorded a brake thermal efficiency of 35.92% against 30.6% for the neat diesel at maximum brake power without much change in smoke density and NOx emissions. However, little increase in HC emissions were recorded up to 60:20:20 blends and the increase is drastic when the methanol content is above 20%

Chockalingam, Sundarraj, Ganapathy, Saravanan

The Effects of Spark Timing and Equivalence Ratio on Spark-Ignition Linear Engine Operation with Liquefied Petroleum Gas

2012-01-04244/16/2012

A prototype of a small, spark-ignition free-piston engine combined with a linear alternator was designed to produce electric power for portable usage. It has a bore size of 25 mm and maximum stroke of 22 mm. The engine was fueled with liquefied petroleum gas consisting of 98% propane. The electric power generated by the linear alternator is a function of the piston dynamics and the electric conductance. Therefore, the purpose of current research is to investigate the effects of the basic engine controlling parameters such as the equivalence ratio of the mixture and the spark timing on the piston dynamics and study the relationship with the electric power generation performance. The equivalence ratio of the mixture was varied from 1.0 to 1.72, while the spark timing was varied at 3, 4, and 5 mm away from the maximum top dead center. Operating characteristics, namely, indicated mean effective pressure, electric power output, operating frequency and piston stroke were analyzed. The spark timing conditions of 4 mm showed the widest operation range in terms of conductance. The advanced spark timing condition of 5 mm was limited in continuous operation due to intermittent misfire. For the retarded spark timing condition of 3 mm, a larger portion of the combustion process took place during the late expansion stroke than under 4 mm conditions, so the indicated mean effective pressure was lower with the same mixture. Therefore, the spark timing of 4 mm resulted in longer stroke and higher frequency than the spark timing condition of 3 mm, which led to higher electric power output. As the conductance was increased, the operation frequency and the piston stroke decreased monotonically for both 3 and 4 mm spark timing conditions. However, the indicated mean effective pressure increased due to the longer scavenging period. Mass fraction burned analysis at the maximum power output condition for each spark timing was conducted to investigate the effect of the equivalence ratio on the combustion characteristics. The mixture with the equivalence ratio of 1.14 showed the shortest average combustion duration. Short combustion duration resulted in a higher indicated mean effective pressure, resulting in higher electric power output. The equivalence ratio of 1.14 and the spark timing of 4 mm were found to be the optimum condition for maximum electric power generation in current research.

Kim, Jaeheun, Bae, Choongsik, Kim, Gangchul

Development of HMC LPI Mono-Fuel Vehicle

2012-01-13144/16/2012

LPG (Liquefied Petroleum Gas), which has a higher content of hydrogen than gasoline, has been attracting worldwide attention for its various advantages. These advantages include low emissions of greenhouse gases and, as a result, LPG has little influence, direct or indirect, on the ozone layer. The electronic feedback-mixing system of a conventional LPG engine, however, has certain disadvantages to a gasoline engine with respect to output, air to fuel ratio control, charging efficiency and fuel economy. For these reasons, the majority of current bi-fuel vehicles in Europe employ a LPI system that injects LPG in liquid state that attempts to make up for the shortcomings of the feedback mixing system. The mono-fuel vehicle recently developed by HMC performs with the same output level, torque and fuel economy as conventional gasoline engines by employing the world's first liquid-state-injection system for exclusive use of LPG. This has improved the problems of the electronic feedback mixing system and bi-fuel LPI system. In particular, the improved fuel economy of the vehicle is expected to help cope with future regulations relating to environmental protection from exhaust fumes.

Kim, In-Tak, Lee, Sang-Hee, Lee, Woo-Jik, Yoon, Jong-Suk

Review on the Effects of Dual-Fuel Operation, Using Diesel and Gaseous Fuels, on Emissions and Performance

2012-01-08694/16/2012

In recent years the automotive industry has been forced to reduce the harmful and pollutant emissions emitted by direct-injected diesel engines. To accomplish this difficult task various solutions have been proposed. One of these proposed solutions is the usage of gaseous fuels in addition to the use of liquid diesel. These gaseous fuels have more gasoline-like properties, such as high octane numbers, and thereby are resistant against auto-ignition. Diesel on the other hand, has a high cetane number which makes it prone to auto-ignition. In this case the gaseous fuel is injected in the inlet manifold, and the diesel is direct injected in the cylinder at the end of the compression stroke. Thereby the diesel fuel spontaneously ignites and acts as an ignition source. The main goals for the use of a dual-fuel operation with diesel and gaseous fuels are the reduction of particulate matter (PM) and nitrogen oxides (NOx) emission. Furthermore, the application of such a dual-fuel operation can offer potential economic and efficiency advantages. Depending on the gaseous fuel used, these goals can be achieved. In general, dual-fuel combustion of gaseous fuels and diesel decreases soot emissions compared with normal diesel combustion except for syngas. Furthermore, increasing load and/or gaseous fuel content leads to a further decrease in soot emissions. Both the application natural gas and liquefied petroleum gas as gaseous fuel offer the possibility to diminish nitrogen oxide emissions probably due to homogenous mixture compositions and/or decreased mixture temperatures. However, using hydrogen or syngas in dual-fuel combustion tends to increase nitrogen oxide emissions; this might be due to the higher flame temperatures and combustion rates of these gasses. Furthermore, the emissions of unburned hydrocarbons and carbon monoxides tend to increase for all evaluated gaseous fuels with dual fuel combustion mainly due to incomplete combustion of mixture trapped in crevices. Efficiencies of the different gaseous fuels are in the same order of magnitude. Some seem to lead to slight efficiency improvements (hydrogen and LPG) while others result in a slight decrease (natural gas and syngas). However, the significant price difference of natural gas and LPG compared to diesel can offer a considerable economic advantage.

Wagemakers, A.M.L.M., Leermakers, C.A.J.

Automotive Engineering International 2012 SAE World Congress Tech Awards

12AEID0403_014/3/2012

The editors of Automotive Engineering International preview the most innovative supplier technologies to be displayed April 24-26 in Detroit at the SAE 2012 World Congress. The top five are highlighted on the following pages, but additional technologies and other event coverage can be viewed online at www.sae.org/mags/aei/saewc. Pinnacle Engines has developed an ultra-efficient engine design based on a four-stroke, spark-ignited (SI), opposed-piston, sleeve-valve architecture using conventional engine manufacturing technology. The company says that the architecture, developed in-house in conjunction with FEV, incorporates two old efficiency ideas into one package, improving both in the process. Opposed-piston engines have been around for quite some time in two-stroke form, but suffer from an emissions perspective. Sleeve-valve engines had some decided advantages in knock resistance and power density, but they too had emissions-related challenges due to the sleeves' lubrication circuit. The Pinnacle design addresses the problem areas for both architectures by combining and improving them. The use of sleeve valves enables a four-stroke cycle in an opposed-piston architecture, and the use of a novel sleeve valve that operates like a traditional poppet valve has allowed the lubrication circuit to be fully isolated from inlet/exhaust flow. The result is an architecture that provides better thermal efficiency through reduced heat loss, improved combustion, and a wider operating range.

Liquefied Natural Gas (LNG) as Fuel for Road Heavy Duty Vehicles Technologies and Standardization

2011-24-01229/11/2011

Natural Gas Vehicle (NGV) engine technology is mainly based on a well-known and already established engine functioning principle, the Otto engine. The recent developments achieved and the OEMs push for this kind of technology clearly shows the confidence and reliability of this technology, especially when it comes to the use of compressed natural gas (CNG). For the above-mentioned reasons, the number of applications involving NGVs has increased worldwide. Environmental and economic reasons, on the whole, have been the main drive for this diffusion. Natural Gas chemical properties are an irrefutable proof of the advanced behavior, environmentally speaking, of a fuel that emits less CO₂ (due to its carbon-hydrogen balance when compared to other fuels) and less NOx and PM. In many countries, favorable taxation schemes have helped the development and entrance into the market of the NGV technology, especially for the light-duty vehicles. Until now, practically no heavy-duty vehicles or lorries have taken advantage of this fuel, because of payload restrictions, and due to the cylinders weight required for a suitable range, an issue requested by specific commercial mission profiles. Nevertheless, Liquefied Natural Gas (LNG) offers the possibility of using this fuel for heavy-duty road transport applications due to its higher energy density. It should be taken into account that a temperature of -162°C is required (at atmospheric pressure) to maintain the fuel in liquid state, therefore the main issue of this technology lies on the cryogenic tank installed on board with a thermal behavior control system and the board vaporizer required to feed the internal combustion engine (ICE). This aspect (on board cryogenic vessels) and some others like the refueling infrastructure still require some standardization work, aspect that is being developed at ISO level. In this context a new interesting opportunity arises with regards to the refueling infrastructure, that is the L-CNG filling stations concept. This application could be used by all types of natural gas vehicles since it's able to deliver both LNG and CNG. The gas in compressed form in this case is obtained from a liquid cryogenic pump at 300 bar followed by a downstream vaporizer, which releases gas in compressed form at 200-250 bar. In this way, a reduced amount of energy is required, when compared to the usual filling stations operated by compressors to build up the CNG from the piped gas.

Bassi, Aldo

Improving Performance in Indirect, Natural Gas Line Heaters

2011-01-10164/12/2011

As a regulated public utility, Consumers Energy constantly struggles to lower operating costs, so that customers can enjoy competitive rates for the natural gas they consume across the state of Michigan. Elimination of line heaters altogether would be one very desirable method of reducing operating cost, unfortunately, Joule Thomson cooling, and the trouble it causes is a fact of life for the natural gas transmission and distribution utilities. Considering this, the operation of line heaters must be optimized so that operating cost can be minimized. Line heaters must be sized appropriately, and controlled so that they are large enough to heat efficiently, but not oversized. Once a heater is installed, the temperature band that it operates within must be set appropriately. This work presents theory that, over time will improve the efficiency of the operation of line heaters within Consumers Energy. Two objectives of this work will be presented. The first objective presented is a model that can be utilized so that line heaters may be sized as efficiently as possible, and then operated at the optimum temperature. A test facility consisting of a heater, associated control and data acquisition equipment was constructed in Flint, Michigan at an existing gas regulator station. At the test facility, studies using the calculated vs. measured bath temperatures in various scenarios have been conducted in order to validate the models reliability. Based on the results, recommendations have been offered, and future work has been proposed that will improve the model as currently programmed. The second objective is to provide a recommendation to where the control point that will control the heater as efficiently as possible, by only calling for heat when required. In addition to the data collected at the test facility, data was collected from, a cross section of heaters from the 2008-2009 heating season. Significant savings can be achieved by the relocation certain installations' control point.

Jawad, Badih Ali, Adams, Kurt, Marshall, Gerald C.

Experimental Studies on the Effect of Vaporizer Heating and Transition Temperature in a Bi-Fuel LPG Vehicle

2011-26-00061/19/2011

Liquefied Petroleum Gas (LPG)-powered vehicles use a pressure regulator/vaporizer to expand and modulate the gas pressure to meet the engine's operational demands. This expansion process is accompanied by a phase change wherein liquid LPG is converted to its gaseous form. This consequently reduces the temperature of the working fluid which may result in freezing (Joule-Thompson effect). In order to aid complete phase change and avoid any freezing, the vaporizer is heated either electrically or by the engine coolant circulation. Any inefficiency in the heating may lead to improper phase change and can result in a phenomenon known as "liquid carryover," wherein a liquid LPG gets entrained in the downstream gas circuit where the gaseous form is demanded. The liquid carryover (if any) leads to the improper engine functioning leading to driveability and emission issues. In bi-fuel (two fuel options - LPG and gasoline) vehicles, operation in LPG is usually avoided until the coolant temperature reaches the optimum "transition temperature" wherein the engine shifts from gasoline mode to LPG operating mode. This paper establishes an experimental technique to efficiently evaluate the liquid carryover phenomenon in LPG gas-fuelled vehicles using the conventional physical measurements of gas temperature and air-fuel ratio. The paper also presents the use of this experimental technique to effectively evaluate the optimum coolant temperature and its mass flow rate required for efficient phase change process. The results presented in this paper are based on the experimental tests conducted on a passenger car powered by a 1.2 l MPFI Bi-fuel engine. The results indicate the presence of liquid LPG in the low pressure gas stream at transition temperatures below 40°C. The tests also establish the effect of transition temperature on catalyst light-off time and emissions. The results indicate that the catalyst light-off time increases as the transition temperature is lowered. The catalyst light-off time increases by 3.5% for a decrease in transition temperature of 15°C. Contrarily, the HC and CO₂ emission decreases by 18% and 2.6% respectively as the transition temperature is lowered by 15°C. CO and NOx emissions showed no perceivable change with changes in transition temperature.

Viswanatha, H. C., Shanmugam, R. Muthu, Srinivasan, L., Kankariya, Nilesh M.

Light Utility Vehicles

J2258_201012 (Historical)

12/8/2010

This SAE Standard defines requirements relating to the elements of design, operation, and maintenance of light utility vehicles. The safety specifications in this document apply to any self-propelled, operator-controlled, off-highway vehicle 1829 mm (72 in) or less in overall width, exclusive of added accessories and attachments, operable on three or more wheels, primarily intended to transport material loads or people, with a gross vehicle weight of 2500 kg (5500 lb) or less, and a maximum design speed less than or equal to 40.23 km/h (25 mph). This document is not intended to cover Go-Karts (ASTM F2007-07a), Fun-Karts (ASTM F2011-02e1), Dune Buggies, and all terrain vehicles (ATVs) complying with ANSI/SVIA 1.

Special Purpose Vehicle Committee