Abstract
During the world energy transformation, using some vegetable oils as fuel enables the production of clean and inexpensive energy with the application of the well-known technology of the CI ...engine. The common rail (CR) fuel system gives many opportunities related to creating an air–fuel mixture and its efficient combustion. Can the system dedicated to diesel oil be used to inject vegetable oil and control its combustion effectively? This paper presents some results of the application of the injection strategy for raw Camelina sativa (CS) oil fueling. The test was conducted on the AVL single-cylinder CI engine equipped with a CR system for engine speed n = 1500 rpm and different excess air coefficients (1.1 < λ < 2.1). The engine parameters and performance obtained for raw CS oil were compared with the results obtained for diesel oil fueling for the same and slightly modified injection strategy. The experiment demonstrated how much the combustion process and its effects differ for these two fuels. In addition, several aspects related to the cultivation and use of Camelina sativa oil as a renewable energy source are presented.
The electromagnetic pulse (EMP) is either a natural phenomenon caused by a solar storm or can be an effect of the deliberately use of destructive weapons. It is a threat to critical infrastructure ...systems, including transportation. The construction of transportation means continues to pursue the rapidly accelerating economy and ecological demands while increasingly becoming more dependent on electricity and electronics each day. The paper presents a method that enables driving a vehicle after an impact of EMP of high energy, where the standard protection systems like insulations or protection shields are not efficient, and the vehicle electrical system is destroyed. The device called the Emergency Fueling Unit (EFU) is described. EFU was installed and tested on a truck equipped with a six-cylinder, 11 L CI engine. The truck acceleration test results presented in the paper confirm that the EFU could be effectively used to drive the truck in case of the destruction of its electrical system. The paper's topic also provides an opportunity to reflect on how and why modern vehicles' powertrains, especially commercial vehicles, are exposed to the influence of phenomena that do not occur in everyday life but can have a disastrous impact on means of transportation and our safety.
The paper presents some research results to recognize the possibility of realization of the idea of a multi-fuel IC engine. Future construction is planned as a flexible solution for military or ...special purpose transport means and emergency power generation. The proposed engine would utilize compression ignition mode for combustion of high reactive fuels (JP-8, diesel oil, etc.) or spark ignition mode for gasoline or other low reactive fuels. Practical implementation of the idea requires that highly reactive fuels be burned efficiently at a low compression ratio suitable for both engine modes. For the test diesel oil, JP-8 and its blends with pure rapeseed oil were chosen as easily accessible fuels. The experiment was carried out on naturally aspirated and supercharged AVL research engine with a common rail system and compression ratio CR = 12. The elaborated, unified injection strategy that synchronized the main dose injection timing with the start of the second stage of homogeneous mixture combustion was checked in practice. The proposed injection strategy applied for CI engine with the low compression ratio enabled efficient combustion and comparable, relatively high engine performance for all tested fuels.
Jet Propellant-8 (JP-8) is used as a fuel for standard CI engine instead of diesel oil, especially in military applications on a large scale. For all such applications, the engine regulation ...parameters are optimal for diesel oil. The properties of kerosene-type fuel, encourage to test different strategies of mixture creation and combustion modes which could be more effective for JP-8 than these elaborated for diesel oil. The paper describes an experiment focused on finding an injection strategy for effective application of JP-8 to a CI engine with low compression ratio. To find an effective way of JP-8 application, the search described in the paper started from the investigation of Low Temperature Combustion (LTC) possibilities, including Homogeneous Charge Compression Ignition (HCCI) engine operation. It led to Partially Premixed Combustion (PPC) with the injection synchronised with the start of mixing controlled phase of combustion. It is also presented how small changes in the injection sequence could heavily influence the combustion phases and very significantly modify the combustion process. For the tests, a naturally aspirated AVL research engine equipped with a common rail system was adapted. The low compression ratio (CR=12:1) was applied. The experiment excluded Exhaust Gas Recirculation (EGR) and mixture dilution with the air. The paper contains the comparison of JP-8 combustion parameters, engine performance and emissions parameters obtained for different injection strategies.
This paper investigates an impact of the exhaust gas recirculation on concentration of selected harmful chemical compounds from the AVL 5402 research diesel engine powered with diesel fuel (DF) and ...compressed natural gas (CNG). In particular the engine was operated in the dual fuel mode. It means that the engine was conventionally fuelled by regular diesel fuel and simultaneously by CNG dosed into the inlet pipe. Necessary tests were carried out for mixtures containing 30, 50 and 70 % by energy content of CNG in the total chemical energy delivered with diesel fuel (DF) into the combustion chamber. Research was conducted for stationary conditions of the engine work at 1200 rpm and constant 1004 Joules of a fuel chemical energy delivered in each cycle into the combustion chamber. In such conditions an impact of the EGR rate changed in range of 0 – 50 % on emissions of selected unburned hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx) as well as particulate matter (PM) was evaluated. Obtained results confirmed that the EGR system is effective in reduction of NOx formation for all tested fuel mixtures. Nevertheless, it was found that addition of CNG combusted in the diesel engine generates more harmful pollutants in comparison with diesel fuel. However, in some cases the concentration of NOx as well as PM was comparable or lower. It suggests that combustion of CNG in diesels allows to achieve environmental benefits. In this case further optimization of engine fuel supply system is necessary.
Elements of car construction, especially the information available on a dashboard, can stimulate the way of driving. The experiment described in the paper aimed to examine how the information ...provided by the indicator, which informs about the operational mode of a gasoline direct injection (GDI) engine, can contribute to eco-driving and the possible learning of acceleration pedal operation by a driver. The analysis of the fuel injection process affected by driver behaviour was an essential part of the experiment. The experiment was divided into two parts. The first one (nine tests) consisted of driving without access to the indicator information. In the second part, the information on the mode of the engine run was available for the driver. The results confirmed that the information about the type of fuel mixture used for the supply of the GDI engine facilitates an economical driving style (about 10% fuel savings) and motivates the driver to engage in eco-driving.
Jet Propellant-8 (JP-8) is used as a fuel for a standard Compression Ignition (CI) engine instead of diesel oil, especially in the military applications. The properties of a kerosene-type fuel, which ...is JP-8, encourage us to test different strategies of mixture creation and combustion which could be more effective for this fuel, than these elaborated for diesel oil. The experiment aimed to show whether it is possible to realise an effective Low Temperature Combustion (LTC) strategy in a CI engine with a low compression ratio for JP-8 fuel. The tests were focused on combustion of a lean homogeneous JP-8/air mixture close to the knock limit. Additionally, the combustion process of the homogeneous mixtures diluted with EGR was examined. AVL research engine with common rail system and low compression ratio (CR=12) was adapted for the tests. In order to create a homogeneous mixture early, multi injection of JP-8 under high (90 MPa) was applied. The results of the HCCI operation were compared to the Partially Premixed Combustion (PPC) mode without EGR, tested on the same engine with a low CR. The experiment showed that it is possible to realise LTC process for the HCCI engine fueled with JP-8, though the knock confined the engine load. The application of EGR allowed to control the phase and rate of the heat release. The higher share of EGR made the HCCI engine cycles less repetitive. Generally, For the HCCI engine operation, CO and total hydrocarbons (THC) emission were on a high level. The PM emission was also relatively high, whereas NOx was maintained on a low level for all of the examined points.
Fast truck-packing of 3D boxes Józefowska, Joanna; Pawlak, Grzegorz; Pesch, Erwin ...
Engineering Management in Production and Services,
06/2018, Letnik:
10, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We present formulation and heuristic solution of a container packing problem observed in a household equipment factory’s sales and logistics department. The main feature of the presented MIP model is ...combining several types of constraints following from the considered application field. The developed best-fit heuristic is tested on the basis of a computational experiment. The obtained results show that the heuristic is capable of constructing good solutions in a very short time. Moreover, the approach allows easy adjustment to additional loading constraints.
The paper presents some results of an examination of a dual fuel compression ignition engine fuelled with natural gas and diesel oil and a new concept of a dual fuel highly efficient internal ...combustion engine. For the examined dual fuel engine the homogeneous air-natural gas mixture was formed outside the engine cylinder and was ignited by a dose of diesel oil directly injected to the cylinder. The analysis of the combustion of a dual fuel mixture is based on cylinder pressure diagrams. The diagrams show some problems connected with self-ignition and control of the combustion of the mixture that should be solved to obtain a better engine performance and lower emissions. Particularly important is the control of the combustion process that causes many problems such as knock combustion or engine overheating. For the above-mentioned solution it is also difficult to reduce the engine emissions of hydrocarbons and nitrogen oxides. As a result of the analysis of the theoretical engine cycle and the dual fuel engine performance as well as some phenomena connected with dual fuelling of compression ignition engines a new idea of fuelling and combustion control was created. Generally, the idea combines Otto and Sabathè theoretical processes in one engine. The Otto process, which is more efficient, would be applied for lower engine load but the Sabathè process with changing share of heat supplied at constant volume is to be applied for higher engine loads. The concept of a dual fuel highly efficient internal combustion engine foresees the application of ethanol and diesel oil and two separate direct injection systems for these fuels as well as spark ignition system which would enable the ignition of stratified ethanol-air mixture. The engine can run in two modes - spark ignition mode (the engine fuelled with ethanol) for lower loads and compression ignition mode (the engine fuelled with ethanol and diesel oil) for higher and full loads. The ethanol-air mixture is lean for both modes. It could also contribute to higher engine efficiency as well as a relatively high maximum cylinder pressure for all range of loads. The tests of the new concept that are to be carried out will focus on the optimization of the engine control parameters. The parameters of the injection of both fuels and amount of air (controlled by throttle) would be changed in a very high range that could give a higher efficiency and lower emissions. It is also possible to apply natural gas instead of ethanol for the new concept of fuelling of IC engine. The concept could be described as dual fuel mixed ignition (DFMI) engine.
The paper concerns complexity studies on the scheduling problem arising in a simple flexible manufacturing system. The system consists of a single machine, one depot (both with unlimited buffers), ...and one vehicle (automated guided vehicle). The vehicle operates according to the regular metro strategy. This means that it travels in cycles of the constant length, without stops, transporting at most one job at a time between the depot and the machine. The machine executes available jobs in the non-preemptive way. The goal is to minimize the schedule length, i.e., to minimize the number of vehicle cycles necessary to transport and execute all jobs in the system. We prove the strong NP-hardness of this problem and show that any list algorithm has the worst-case performance ratio equal to 2. Moreover, we mention that special cases of the considered problem, with zero transportation times from the depot to the machine and from the machine to the depot, are polynomially solvable.
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