The impact of marine engine operation and maintenance on emissions

2012 ◽  
Vol 17 (1) ◽  
pp. 54-60 ◽  
Author(s):  
Vanessa Duran ◽  
Zigor Uriondo ◽  
Juan Moreno-Gutiérrez
Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler

Cycle-to-cycle variations (CCV) in spark-ignited (SI) engines impose performance limitations and in the extreme limit can lead to very strong, potentially damaging cycles. Thus, CCV force sub-optimal engine operating conditions. A deeper understanding of CCV is key to enabling control strategies, improving engine design and reducing the negative impact of CCV on engine operation. This paper presents a new simulation strategy which allows investigation of the impact of individual physical quantities (e.g., flow field or turbulence quantities) on CCV separately. As a first step, multi-cycle unsteady Reynolds-averaged Navier–Stokes (uRANS) computational fluid dynamics (CFD) simulations of a spark-ignited natural gas engine are performed. For each cycle, simulation results just prior to each spark timing are taken. Next, simulation results from different cycles are combined: one quantity, e.g., the flow field, is extracted from a snapshot of one given cycle, and all other quantities are taken from a snapshot from a different cycle. Such a combination yields a new snapshot. With the combined snapshot, the simulation is continued until the end of combustion. The results obtained with combined snapshots show that the velocity field seems to have the highest impact on CCV. Turbulence intensity, quantified by the turbulent kinetic energy and turbulent kinetic energy dissipation rate, has a similar value for all snapshots. Thus, their impact on CCV is small compared to the flow field. This novel methodology is very flexible and allows investigation of the sources of CCV which have been difficult to investigate in the past.


2020 ◽  
Vol 181 (2) ◽  
pp. 46-52
Author(s):  
Filip SZWAJCA ◽  
Krzysztof WISŁOCKI

Gas engines are a viable source of propulsion due to the ecological indicators of gas fuels and the large amount of the needed natural resources. Combustion of lean homogeneous gas mixtures allows achieving higher thermal efficiency values, which is a key factor in current engine development trends. Using the spark-jet ignition system (also called as Turbulent Jet Ignition or Two-stage combustion) significantly improves the efficiency and stability of the combustion process, especially in the part-load operation on lean or very lean mixtures. This paper presents the impact of using two different fuel injection methods: Port Fuel Injection or Mixer on the operation stability of a gas engine designed for LDVs. Comparative studies of two different mixture preparation systems were carried out on a single-cylinder AVL 5804 test engine. By re-cording the cylinder pressure for a significant number of engine cycles, it became possible to determine the repeatability of engine operation and to correlate the results with the mixture formation system and the air-fuel ratio. In the performed research the beneficial effect of the mixer system application on the engine operation stability in the part-load conditions was found.


Author(s):  
Ghenadie Bulat ◽  
Dorian Skipper ◽  
Robin McMillan ◽  
Khawar Syed

This paper presents a system for the active control of the fuel split within a two-stream Dry Low Emissions (DLE) gas turbine. The system adjusts the fuel split based upon the amplitude of combustor pressure fluctuations and burner metal temperature. The active control system, its implementation and its performance during engine tests on Siemens SGT-200 is described. The paper describes the active fuel split control algorithm. Engine test results are then presented for steady and transient loads with different rates of change of the engine operation temperature, including rapid load acceptance and load shedding. Additionally, cycling operating conditions were tested to evaluate the performance of the algorithm in typical island mode and mechanical drive applications. The active control algorithm was successful in providing stable and reliable control of the turbine allowing very low emissions levels to be attained without manual intervention. In fact it allows areas to be reached that until now were excluded. The impact of operational parameter changes (e.g. load change, ambient temperature, fuel composition etc.) on the engine operability proved the active control software’s ability to respond seamlessly. In addition, it prevented flameout and/or high pressure fluctuation while keeping burner temperatures within limits. Recorded emissions showed a reduction in NOx was achieved when the fuel split was controlled by the algorithm compared to standard operation. This was a direct result of the algorithm successfully identifying the lean stability limit and operating close to it.


Author(s):  
Clifford F. Ash

Rapidly increasing fuel costs, the increasing complexity of the new engines now available, along with the inaccuracies, inefficiencies and long test cycles inherent in manual testing push the cost of engine testing to unnecessary levels. One promising avenue of relief is the automation of gas turbine testing through the use of real-time computer data acquisition and processing systems. Remarkable progress has been made in the area of closed-loop or fully automatic operation of the test process from start-up using various programmable steps, recording results as dictated by the test procedure, controlling operation and a safe engine shut down. This paper discusses the successful application of a real-time computer system with both closed and open-loop capabilities. This particular system called “ADAPS™” (Automatic Data Acquisition and Processing System) handled its first 3,000 hours of engine operation without a single hardware or software interruption. Savings in manpower alone in that period was nearly 18,000 man-hours.


2001 ◽  
Vol 36 (6) ◽  
pp. 408-416
Author(s):  
Kuniyuki Matsushita ◽  
Kazuhiko Nagao ◽  
Kazuaki Yano

Author(s):  
Aditya Prakash Singh ◽  
Gordon Patrick McTaggart-Cowan ◽  
Patrick Kirchen

Abstract Dilution of natural gas fuel with air for use in a pilot ignited direct injection natural gas engine was investigated to evaluate the impact of this strategy on emissions and engine performance. A representative heavy-duty mode (mid to high-load at medium speed) was considered and the equivalence ratio (Φ) and exhaust gas recirculation (EGR) rates were varied from this representative mode. Air dilution resulted in a significant reduction in several pollutants: 90 to 97% reductions in black carbon particulate matter, 45 to 95% reductions in carbon monoxide, 68 to 85% reductions in total unburnt hydrocarbons. NOx emissions were found to increase by between 1.5 and 2.5x, depending on Φ and EGR, for a fixed combustion phasing. Beyond the emissions improvements, the gross indicated thermal efficiency increased by 2.5 percentage points at both high and low EGR rates. At higher EGR rates, this improvement was due to improved combustion efficiency, while the mechanism for efficiency improvement at lower EGR rates was unclear. The application of air-fuel dilution requires compressed air (> 300 bar) to mix with natural gas at high pressures. A system level analysis considered the compression power required by an industrial 3-stage reciprocating compressor and indicated that the gross indicated thermal efficiency improvements could compensate for the compression requirements for engine operation at high Φ.


2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Mohammad Javad Nekooei ◽  
Jaswar Jaswar ◽  
A. Priyanto

This research reviews a close loop control-oriented model, combined with air to fuel ratio, to regulate  combustion phasing in a spark- ignition marine engine operation. On the other hand ,Stoichiometric air-to-fuel ratio () control plays a significant role on the  three way catalysts in the reduction of exhaust pollutants of the SI marine engine. Air to fuel management for SI marine engines is a major challenge from the control point of view because of the highly nonlinear behavior of this system. For this reason, linear control techniques are unable to provide the required performance, and nonlinear controllers are used instead. Therefore, a fuzzy MIMO Control system is designed for robust control of  lambda. As an accurate and control oriented model, an  air to fuel ratio model of a Spark Ignition (SI) marine engine is developed to generate simulation data of the engine's subsystems. The Goal of this control is to maintain the A/F ratio at stoichiometry.


2017 ◽  
Vol 8 (2) ◽  
pp. 73-77
Author(s):  
Muhammad Fakhrurozi ◽  
Askan Askan

The development of technology and industry has also affected the level of pollution. Side effects that are very influential on human health include the level of noise that comes out of the exhaust gas (exhaust). Sound pollution comes from either gasoline-fueled or diesel-fueled engine vehicles, especially in diesel engines. To reduce noise levels there are several ways that can be done; (1) Giving a silencer to the engine, (2) Designing a muffler on the exhaust gas line, (3) Placing the sound source in the correct position, and (4) Setting the engine operation and maintenance schedule. One way to reduce the noise level in a diesel engine is to trap a particulate trap installed in the exhaust gas (exhaust). This method can reduce the gas particles from combustion to the disposal process, so that the noise level can be reduced. The purpose of this study was to determine how much influence the installation of particulate trap made of brass metal in the exhaust of a diesel engine to the level of noise caused. This study uses a factorial type random design by varying the weight of the active ingredient of metal particulate trap 200gr, 300gr, 400g at engine speed between 900-1700rpm. The results of this study indicate that the lowest noise level is obtained from a 300 gr particulate trap ranging from 79.3 dB - 79.4 dB.


2021 ◽  
Author(s):  
Matheus Marques da Silva ◽  
Constantin Kiesling ◽  
Christof Gumhold ◽  
Sven Warter ◽  
Andreas Wimmer ◽  
...  

Abstract In order to rise to global challenges such as climate change, environmental pollution and conservation of resources, internal combustion engine manufacturers must meet the requirements of substantially reduced emissions of CO2 and other greenhouse gases, zero pollutant emissions and increased durability. This publication addresses approaches that can help improve engine efficiency and durability through the engine crankshaft bearing and lubricant system. An understanding of the operating behavior of key engine components such as crankshaft main bearings in fired engine operation allows the development of appropriate tools for bearing condition monitoring and condition-based maintenance so as to avoid critical engine operation and engine failure as well as unnecessary engine downtime. Such tools are especially important when newly developed low viscosity oils are employed. Though these oils have the potential to reduce friction and to increase engine efficiency, their use comes with a higher risk of accelerated bearing wear and ultimately bearing failure. The specific target of this paper is therefore to obtain detailed knowledge of the influence of engine operating parameters and oil parameters on crankshaft main bearing temperature behavior and engine friction behavior in fired operation as a starting point for condition monitoring and condition-based maintenance approaches and as a basis for improving the bearing and lubricant system as a whole. To achieve this target, experimental investigations were carried out on an engine test bed employing an in-line six-cylinder heavy-duty diesel engine with a displacement of approximately 12.4 dm3. Defined and accurately reproducible engine operating conditions were ensured by comprehensive external conditioning systems for the coolant, lubricating oil, fuel, charge air and ambient air. Since the focus was on investigating the bearing and friction behavior by means of the base engine, several auxiliary systems were removed; these included the lubricating oil and coolant pumps, the front-end accessory drive and the generator. Each crankshaft main bearing was instrumented with a thermocouple on the back of its bottom bearing shell to measure the bearing temperature. Piezoelectric pressure transducers were applied to all six cylinders in order to facilitate the accurate determination of the friction mean effective pressure (FMEP) based on indicated and brake mean effective pressures. The variations in engine operating parameters (engine speed and torque) mainly serve as a reference for the variations in oil parameters. They confirm the existing knowledge that engine speed has a significant impact on FMEP and bearing temperature while the impact of engine torque is comparatively low. The variations in oil parameters reveal that lowering the viscosity grade from SAE 10W-40 to 5W-20 leads to a decrease in both bearing temperature and FMEP, which can be explained by the lower fluid friction in the bearing system and the increased mass flow and convective heat transport with the lower viscosity oil. An increase in the lubricating oil temperature at the engine inlet leads to a significant increase in bearing temperature and a decrease in FMEP; the former is explained by the increased heat influx from the lubricant oil, and the latter is caused mainly by the temperature dependency of the lubricant oil viscosity and its impact on fluid friction. The impact of engine oil inlet pressure on bearing temperature and FMEP is generally found to be low. The results will serve as the basis for future research that includes approaches to condition monitoring and evaluating improved engine operating strategies with regard to oil parameters.


2021 ◽  
Author(s):  
Richard Morrison ◽  
Charles Stuart ◽  
Sung In Kim ◽  
Stephen Spence ◽  
Andre Starke ◽  
...  

Abstract Automotive engine downsizing has placed an increased focus on the ability of the turbocharger to provide adequate boost levels across the full engine operating rage. To achieve the desired levels of turbocharger performance the turbine must be capable of operating effectively at the intended design point and also at off-design conditions. Mixed flow turbines (MFTs) provide a potential method to improve performance at off-design conditions and during transient engine operation. A unique feature of a MFT is the spanwise variation of incidence angle at the rotor leading edge. This results in additional flow separation from the blade suction surface near the hub under a wide range of operating conditions. The flow separation generates additional loss and has a detrimental impact on turbine performance. A novel design of turbine volute similar to a conventional twin-entry turbine volute was examined. The novel turbine volutes were designed to produce a spanwise variation in flow conditions at the rotor inlet. The primary objective was to reduce the incidence angle and increase the mass flow rate at the hub side of the passage relative to the shroud side, as it has previously been identified that this can be beneficial for MFT performance. A number of different volute geometries were examined by numerical analysis to determine the impact of key parameters on turbine performance. The results indicated that generating a suitable spanwise flow distribution could produce a moderate improvement in turbine efficiency at off-design operating conditions. The novel volute design also provided a means of achieving a degree of variable geometry operation to further improve off-design performance. Turbine performance was examined under the variable geometry operation and an improvement in turbine power output at low speed, off-design conditions was achieved. This was analogous to operating with a conventional pivoting vane variable geometry system and had the potential to benefit performance during transient engine operation.


Sign in / Sign up

Export Citation Format

Share Document