Semiclosed Cycle Internal Combustion Engine Utilizing Cryogenic Exhaust Solidification for Undersea Applications

1974 ◽  
Vol 96 (3) ◽  
pp. 1089-1096
Author(s):  
A. D. Rathsam

The paper describes the design, hardware, testing, and performance of a breadboard semi-closed cycle power system proposed for undersea operations by the Naval Undersea Center. The work was performed to prove the feasibility of the system. The system includes a commercially available spark-ignition engine, which operates on natural gas, oxygen, and recirculated exhaust gas, and a specially designed liquid oxygen/excess exhaust gas converter. The converter utilizes heat from dry, precooled exhaust gas to vaporize liquid oxygen and provide oxygen for the engine. While providing heat for liquid oxygen vaporization, the exhaust gas becomes frozen. The well-insulated converter is designed with ample storage capacity for both liquid oxygen and solidified exhaust. Nonoptimized hardware provided reliable airbreathing and nonairbreathing operation. Tests indicate that the approach is feasible for undersea applications.

2019 ◽  
Vol 179 (4) ◽  
pp. 86-92
Author(s):  
Mieczysław DZIUBIŃSKI ◽  
Ewa SIEMIONEK ◽  
Artur DROZD ◽  
Michał ŚCIRKA ◽  
Adam KISZCZAK ◽  
...  

The article discusses the impact of ignition system damage on the emission of toxic subcategories in a spark-ignition internal combustion engine. The aim of the work was to develop an analytical model of ignition system diagnostics, test performance and comparative analysis of the results of simulations and experiments. The model developed allows to analyse the basic parameters of the ignition system affecting the content of toxic substances in the exhaust. Experimental tests were carried out using the MAHA MGT5 exhaust gas analyser for four different combustion engines fueled with petrol at various operating conditions. During the tests, the content of toxic substances in the exhaust gas of a properly working engine and the engine working with damage to the ignition system were registered. The tests will be used to assess the impact of the damage of the spark-ignition engine on the emission of individual components of toxic fumes.


Author(s):  
Dinesh D. Adgulkar ◽  
N. V. Deshpande ◽  
S. B. Thombre ◽  
I. K. Chopde

By supporting hydrogen as an alternative fuel to the conventional fuel i.e. gasoline, new era of renewable and carbon neutral energy resources can be introduced. Hence, development of hydrogen fuelled internal combustion engine for improved power density and less emission of NOx has become today’s need and researchers are continuously extending their efforts in the improvement of hydrogen fuelled internal combustion engine. In this work, three dimensional CFD simulations were performed using CFD code (AVL FIRE) for premixed combustion of hydrogen. The simplified 3D geometry of engine with single valve i.e. inlet valve was considered for the simulation. Various combustion models for spark ignition for hydrogen i.e. Eddy Breakup model, Turbulent Flame Speed Closure Combustion Model, Coherent Flame model, Probability Density Function model were tested and validated with available simulation results. Results obtained in simulation indicate that the properties of hydrogen i.e. high flame speed, wide flammability limit, and high ignition temperature are among the main influencing factors for hydrogen combustion being different than that of gasoline. Different parameters i.e. spark advance angle (TDC to 40° before TDC in the step of 5°), rotational speed (1200 to 3000 rpm in the step of 300 rpm), equivalence ratio (0.5 to 1.2 in the step of 0.1), and compression ratio (8, 9 and 10) were used to simulate the combustion of hydrogen in spark ignition engine and to investigate their effects on the engine performance, which is in terms of pressure distribution, temperature distribution, species mass fraction, reaction progress variable and rate of heat release for complete cycle. The results of power output for hydrogen were also compared with that of gasoline. It has been observed that power output for hydrogen is almost 12–15% less than that of gasoline.


2020 ◽  
Vol 10 (24) ◽  
pp. 8979
Author(s):  
Andrea Matrisciano ◽  
Tim Franken ◽  
Laura Catalina Gonzales Mestre ◽  
Anders Borg ◽  
Fabian Mauss

The use of chemical kinetic mechanisms in computer aided engineering tools for internal combustion engine simulations is of high importance for studying and predicting pollutant formation of conventional and alternative fuels. However, usage of complex reaction schemes is accompanied by high computational cost in 0-D, 1-D and 3-D computational fluid dynamics frameworks. The present work aims to address this challenge and allow broader deployment of detailed chemistry-based simulations, such as in multi-objective engine optimization campaigns. A fast-running tabulated chemistry solver coupled to a 0-D probability density function-based approach for the modelling of compression and spark ignition engine combustion is proposed. A stochastic reactor engine model has been extended with a progress variable-based framework, allowing the use of pre-calculated auto-ignition tables instead of solving the chemical reactions on-the-fly. As a first validation step, the tabulated chemistry-based solver is assessed against the online chemistry solver under constant pressure reactor conditions. Secondly, performance and accuracy targets of the progress variable-based solver are verified using stochastic reactor models under compression and spark ignition engine conditions. Detailed multicomponent mechanisms comprising up to 475 species are employed in both the tabulated and online chemistry simulation campaigns. The proposed progress variable-based solver proved to be in good agreement with the detailed online chemistry one in terms of combustion performance as well as engine-out emission predictions (CO, CO2, NO and unburned hydrocarbons). Concerning computational performances, the newly proposed solver delivers remarkable speed-ups (up to four orders of magnitude) when compared to the online chemistry simulations. In turn, the new solver allows the stochastic reactor model to be computationally competitive with much lower order modeling approaches (i.e., Vibe-based models). It also makes the stochastic reactor model a feasible computer aided engineering framework of choice for multi-objective engine optimization campaigns.


Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6473
Author(s):  
Stanislaw Szwaja ◽  
Michal Gruca ◽  
Michal Pyrc ◽  
Romualdas Juknelevičius

Investigation of a new type of fuel for the internal combustion engine, which can be successfully used in both the power generation and the automotive industries, is presented in this article. The proposed fuel is a blend of 75% n-butanol and 25% glycerol. The engine tests conducted with this glycerol–butanol blend were focused on the performance, combustion thermodynamics, and exhaust emissions of a spark-ignition engine. A comparative analysis was performed to find potential similarities and differences in the engine fueled with gasoline 95 and the proposed glycerol–butanol blend. As measured, CO exhaust emissions increased, NOx emissions decreased, and UHC emissions were unchanged for the glycerol–butanol blend when compared to the test with sole gasoline. As regards the engine performance and combustion progress, no significant differences were observed. Exhaust temperature remarkably decreased by 3.4%, which contributed to an increase in the indicated mean effective pressure by approximately 4% compared to gasoline 95. To summarize, the proposed glycerol–butanol blend can be directly used as a replacement for gasoline in internal combustion spark-ignition engines.


Author(s):  
Andreas A. Malikopoulos ◽  
Panos Y. Papalambros ◽  
Dennis N. Assanis

Advanced internal combustion engine technologies have increased the number of accessible variables of an engine and our ability to control them. The optimal values of these variables are designated during engine calibration by means of a static correlation between the controllable variables and the corresponding steady-state engine operating points. While the engine is running, these correlations are being interpolated to provide values of the controllable variables for each operating point. These values are controlled by the electronic control unit to achieve desirable engine performance, for example in fuel economy, pollutant emissions, and engine acceleration. The state-of-the-art engine calibration cannot guarantee continuously optimal engine operation for the entire operating domain, especially in transient cases encountered in driving styles of different drivers. This paper presents the theoretical basis and algorithmic implementation for allowing the engine to learn the optimal set values of accessible variables in real time while running a vehicle. Through this new approach, the engine progressively perceives the driver’s driving style and eventually learns to operate in a manner that optimizes specified performance indices. The effectiveness of the approach is demonstrated through simulation of a spark ignition engine, which learns to optimize fuel economy with respect to spark ignition timing, while it is running a vehicle.


2016 ◽  
Vol 14 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Ondřej Bolehovský ◽  
Jan Macek

Abstract This research uses 1-D simulation in GT-Power for evaluation of boosting systems for a spark ignition engine. Exhaust gas driven (waste-gated turbocharger) and mechanical driven (Roots blower) boosting systems are assessed in both steady state and transient modes in terms of performance, efficiency, fuel consumption, drivability, energy distribution and other aspects that influence gas exchange phase. Moreover, different boost control strategies, particularly at partial load, are also evaluated. Results of the research are aimed at helping identify an optimal boosting system for standardized or real-world drive cycles.


Author(s):  
Jerald A. Caton

The second law of thermodynamics provides the mechanism for assessing the quality of energy. The non-conserved property used for this assessment is called exergy, availability or available energy. For the internal combustion engine, the exergy of the fuel is distributed among work, heat transfer, exhaust, and is destroyed by several processes. The major destruction of exergy for the internal combustion engine is during the combustion process. This paper documents this destruction for a wide range of engine operating parameters, design parameters, and fuels. A 5.7 liter, spark ignition, automotive engine was selected for this study. Operating parameters that were examined included equivalence ratio, speed, load and spark timing. Design parameters that were examined included compression ratio, expansion ratio and the use of turbocharging. Combustion parameters and oxidizer were examined as well. The fuels examined included isooctane (base), methane, propane, hexane, methanol, ethanol, hydrogen and carbon monoxide. For the part load base case (1400 rpm and a bmep of 325 kPa) using isooctane, the destruction of exergy was 21% of the fuel exergy. For many of the engine operating and design parameters, this destruction was relatively constant (between about 20 and 23%). The parameters that resulted in the greatest change of the exergy destruction were (1) exhaust gas recirculation, and (2) inlet oxygen concentration. In general, the amount of the destruction of exergy during the combustion processes was associated with the level of the combustion temperatures.


Sign in / Sign up

Export Citation Format

Share Document