Supercharging of SI Engines Using a New Kind of Screw-Type Supercharger

2001 ◽  
Author(s):  
K. von Rueden ◽  
H. Pucher ◽  
J. Nickel
Keyword(s):  
Slide Valve ◽  
Operating Conditions ◽  
Load Control ◽  
Transient Operation ◽  
Si Engine ◽  
Si Engines ◽  
New Type ◽  
Simulation Results ◽  
Stroke Cycle ◽  
Engine Power

Abstract In result of the permanent endeavor to reduce fuel consumption of vehicle engines, nowadays the implementation of downsizing concepts is being enforced. Thereby the desired nominal engine power can be produced by an engine with lower displacement operating with correspondingly higher charging pressure. Mechanical supercharging as well as turbocharging can be considered as a suitable supercharging method. This paper reports on experimental and simulation results regarding the stationary and transient operation of a four-stroke cycle SI passenger car engine supercharged by a new type of screw-type supercharger. In this manner the load control of the SI engine is performed by a supercharger internal slide valve system. Thus not only the throttling losses will be reduced noticeably, but also expansion work can be regained by this supercharger under certain operating conditions. The results obtained will be compared with those of the turbocharged reference engine.

Investigation of a Novel Fuel Injection Technology Aimed to Reduce Cold-Start Emissions in SI Engines

2002 ◽  
Author(s):  
Brian T. Reese ◽  
Yann G. Guezennec ◽  
Miodrag Oljaca
Keyword(s):  
Fuel Injection ◽  
Cold Start ◽  
Operating Conditions ◽  
The Novel ◽  
Fuel Injector ◽  
Si Engine ◽  
Fuel Droplets ◽  
Si Engines ◽  
Atomization Characteristics ◽  
Injection Technology

A novel fuel atomization device (Nanomiser™) was evaluated under laboratory conditions with respect to its ability to reduce SI engine cold-start hydrocarbon emissions. First, comparisons between the level of atomization using the conventional, pintle-type fuel injector and the novel atomizer were carried out using flow visualization in a spray chamber and particle size distribution. The novel atomizer is capable of producing sub-micron fuel droplets, which form an ultra-fine mist with outstanding non-wetting characteristics. To capitalize on these atomization characteristics, this device was compared to a conventional fuel injector in a small, two-cylinder, SI engine under a number of operating conditions. Results show a slightly enhanced combustion quality and lean limit under warm operating conditions and a dramatic reduction in unburned HC emission under cold operating conditions, with cold emissions with the Nanomiser™ matching those with a conventional injector under fully warm conditions.

Control of Air Fuel Ratio in SI Engine Using Optimization

2010 ◽  
Author(s):  
Ali Amini ◽  
Mehdi Mirzaei ◽  
Rahim Khoshbakhti Saray
Keyword(s):  
Control Law ◽  
Nonlinear Controller ◽  
Dynamics Model ◽  
Si Engine ◽  
Controlled System ◽  
Fuel Ratio ◽  
Si Engines ◽  
Simulation Results ◽  
Nonlinear Control Law ◽  
Uncontrolled System

The air fuel ratio (AFR) control is one of the effective methods to reduce emission and fuel consumption in spark ignition (SI) engines. Due to the hard nonlinearities existing in the engine dynamics model, a nonlinear controller should be designed for AFR control. In this Paper, an optimization-based nonlinear control law is developed for injected fuel mass flow to maintain AFR in the stoichiometric value. Simulation results show that the AFR in the controlled system is very close to the desired value, unlike the uncontrolled system in which the AFR has intensive fluctuations.

scholarly journals Experimental research made during a city cycle on the feasibility of electrically charged SI engines

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Levente Kocsis ◽  
Nicolae Burnete
Keyword(s):  
Energy Consumption ◽  
Experimental Research ◽  
Operating Conditions ◽  
Si Engine ◽  
Driving Style ◽  
Functional Parameters ◽  
Performance Improvements ◽  
Compact Class ◽  
Si Engines ◽  
Electrically Charged

AbstractThe paper presents experimental research on performance improvements in a city cycle (operating mostly transient) of a compact class vehicle equipped with a turbocharged SI engine which had attached an electric charger, to improve engine response at low operational speeds. During tests, functional parameters, energy consumption of the electric charger and vehicle performances were measured while driving in two operating conditions: with active and inactive electric charger. The tests were carried out on a well-defined path, in the same driving style, by the same driver.

scholarly journals A New Method to Determine the Impact of Individual Field Quantities on Cycle-to-Cycle Variations in a Spark-Ignited Gas Engine

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Kinetic Energy ◽  
Negative Impact ◽  
Operating Conditions ◽  
Engine Operation ◽  
Gas Engine ◽  
Cycle Simulation ◽  
Simulation Results ◽  
The Impact

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.

scholarly journals Octane Index Applicability over the Pressure-Temperature Domain

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 607
Author(s):  
Tommy R. Powell ◽  
James P. Szybist ◽  
Flavio Dal Forno Chuahy ◽  
Scott J. Curran ◽  
John Mengwasser ◽  
...  
Keyword(s):  
High Efficiency ◽  
National Laboratory ◽  
Operating Conditions ◽  
Dominant Factor ◽  
Compression Ignition ◽  
Oak Ridge ◽  
Operating Modes ◽  
Wide Range ◽  
Thermodynamic Conditions ◽  
Si Engines

Modern boosted spark-ignition (SI) engines and emerging advanced compression ignition (ACI) engines operate under conditions that deviate substantially from the conditions of conventional autoignition metrics, namely the research and motor octane numbers (RON and MON). The octane index (OI) is an emerging autoignition metric based on RON and MON which was developed to better describe fuel knock resistance over a broader range of engine conditions. Prior research at Oak Ridge National Laboratory (ORNL) identified that OI performs reasonably well under stoichiometric boosted conditions, but inconsistencies exist in the ability of OI to predict autoignition behavior under ACI strategies. Instead, the autoignition behavior under ACI operation was found to correlate more closely to fuel composition, suggesting fuel chemistry differences that are insensitive to the conditions of the RON and MON tests may become the dominant factor under these high efficiency operating conditions. This investigation builds on earlier work to study autoignition behavior over six pressure-temperature (PT) trajectories that correspond to a wide range of operating conditions, including boosted SI operation, partial fuel stratification (PFS), and spark-assisted compression ignition (SACI). A total of 12 different fuels were investigated, including the Co-Optima core fuels and five fuels that represent refinery-relevant blending streams. It was found that, for the ACI operating modes investigated here, the low temperature reactions dominate reactivity, similar to boosted SI operating conditions because their PT trajectories lay close to the RON trajectory. Additionally, the OI metric was found to adequately predict autoignition resistance over the PT domain, for the ACI conditions investigated here, and for fuels from different chemical families. This finding is in contrast with the prior study using a different type of ACI operation with different thermodynamic conditions, specifically a significantly higher temperature at the start of compression, illustrating that fuel response depends highly on the ACI strategy being used.

scholarly journals A Flexible Load Control Strategy for Distribution Network to Reduce the Line Losses and to Eliminate the Transmission Congestion

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Beibei Wang ◽  
Xiaoqing Hu ◽  
Peifeng Shen ◽  
Wenlu Ji ◽  
Yang Cao ◽  
...  
Keyword(s):  
Power Distribution ◽  
Distribution Systems ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Test System ◽  
Operating Conditions ◽  
Load Control ◽  
Transmission Congestion ◽  
Heavy Load ◽  
Flexible Load

There are many uncertain factors in the modern distribution network, including the access of renewable energy sources and the heavy load level. The existence of these factors has brought challenges to the stability of the power distribution network, as well as increasing the risk of exceeding transmission capacity of distribution lines. The appearance of flexible load control technology provides a new idea to solve the above problems. Air conditioners (ACs) account for a great proportion of all loads. In this paper, the model of dispatching AC loads in the regional power grid is constructed, and the direct load control (DLC) method is adopted to reduce the load of ACs. An improved tabu search technique is proposed to solve the problem of network dispatch in distribution systems in order to reduce the resistive line losses and to eliminate the transmission congestion in lines under normal operating conditions. The optimal node solution is obtained to find the best location and reduction capacity of ACs for load control. To demonstrate the validity and effectiveness of the proposed method, a test system is studied. The numerical results are also given in this article, which reveal that the proposed method is promising.

Steady-State and Transient Operation Simulation of a “Downsized” Turbocharged SI Engine

2007 ◽  
Author(s):  
F. Bozza ◽  
A. Gimelli ◽  
L. Strazzullo ◽  
E. Torella ◽  
C. Cascone
Keyword(s):  
Steady State ◽  
Transient Operation ◽  
Si Engine

Thermodynamic Analysis of a Multi-Fueled Single Cylinder SI Engine

2011 ◽  
Author(s):  
M. Z. Haq ◽  
M. R. Mohiuddin
Keyword(s):  
Thermodynamic Analysis ◽  
Chemical Properties ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Si Engine ◽  
Gaseous Species ◽  
Single Cylinder ◽  
Engine Cylinder ◽  
Si Engines

The paper presents a thermodynamic analysis of a single cylinder four-stroke spark-ignition (SI) engine fuelled by four fuels namely iso-octane, methane, methanol and hydrogen. In SI engines, due to phenomena like ignition delay and finite flame speed manifested by the fuels, the heat addition process is not instantaneous, and hence ‘Weibe function’ is used to address the realistic heat release scenario of the engine. Empirical correlations are used to predict the heat loss from the engine cylinder. Physical states and chemical properties of gaseous species present inside the cylinder are determined using first and second law of thermodynamics, chemical kinetics, JANAF thermodynamic data-base and NASA polynomials. The model is implemented in FORTRAN 95 using standard numerical routines and some simulation results are validated against data available in literature. The second law of thermodynamics is applied to estimate the change of exergy i.e. the work potential or quality of the in-cylinder mixture undergoing various phases to complete the cycle. Results indicate that, around 4 to 24% of exergy initially possessed by the in-cylinder mixture is reduced during combustion and about 26 to 42% is left unused and exhausted to the atmosphere.

Design Optimization of Autoswitch Hydrogen Absorption and Desorption Device Using Metal Hydrides

2017 ◽  
Vol 15 (6) ◽  
Author(s):  
Ceng He ◽  
Yuqi Wang ◽  
Jing Song ◽  
Shanshan Li ◽  
Fusheng Yang ◽  
...  
Keyword(s):  
Metal Hydride ◽  
Cycle Time ◽  
Single Cycle ◽  
Desorption Process ◽  
Operation Conditions ◽  
Time Simulation ◽  
Structure Improvement ◽  
New Type ◽  
Simulation Results ◽  
Desorption Cycle

Abstract Metal hydride is an influential and promising material for hydrogen utilization. Researchers have carried out a large number of studies on hydrogen storage apparatus, and developed a few new devices for its promotion. Unfortunately, for most metal hydride reactors, the hydrogenation and dehydrogenation are two independent processes owing to the different required conditions, which could cause many inconveniences and safety problems to the H2 absorption & desorption cycle with high frequency and intensity. Hence we proposed a new type of autoswitch H2 absorption & desorption device based on the structure improvement, which consists of rotation disc, fixed disc and the reactor. The numerical simulation for H2 absorption/desorption using LaNi5 was accomplished, and the optimizations on both structure and operation conditions were achieved within a certain period of cycle time. Simulation results show when the single cycle time is set to 1600 s, the absorption temperature has to be lower than 45 °C (3 MPa) and pressure higher than 1.28 MPa (20 °C), and the desorption temperature should be higher than 41 °C (0.1 MPa) and pressure lower than 0.48 MPa (80 °C) under the same cycle time. Meanwhile, the effects of reaction finish time, operating temperature and H2 pressure during absorption/desorption process was investigated and simulation data were also fitted to develop the structural optimization. Under the hydrogenation/dehydrogenation conditions of 3 MPa (20 °C)/0.1 MPa (80 °C), the simulation results indicate the optimal initial reacted fraction and total cycle time are 0.07 and 1287 s, respectively. Moreover, both structures of autoswitch device with 4 and 6 openings have been optimized to satisfy the requirement of each stage. The autoswitch H2 absorption & desorption device can realize the automatic switch between hydrogenation and dehydrogenation orderly and controllably, which would provide convenience for the occasions with this demand and show its remarkable value during popularization and application.

Agglomeration Technologies of Processing Powder Wastes

2015 ◽  
Vol 244 ◽  
pp. 121-129
Author(s):  
Marian Peciar ◽  
Roman Fekete ◽  
Peter Peciar
Keyword(s):  
Research Work ◽  
Operating Conditions ◽  
Airborne Particles ◽  
Raw Material ◽  
Production Cycle ◽  
Shear Forces ◽  
Material Resources ◽  
New Type ◽  
Two Phases ◽  
High Technologies

This article deals with the presentation of modern applications for processing powdered, primarily hazardous, waste to an agglomeration form appropriate for subsequent processing by classical methods, for example in the construction, automotive and consumer goods industries. The aim of the research work was to set appropriate operating conditions in order to appreciate currently non-processable wastes resulting from the intensive production of often extremely expensive materials. Technologies which enable returning powder waste back into the primary production cycle were developed and experimentally tested, thus saving raw material resources. When necessary for the fixing of fine airborne particles with a problematic compacting curve (hard to compress, repulsive due to the surface charge) extrusion processes using a patented technology enabling controlled modification of shear forces in the extrusion zone were successfully applied. A new type of axial extruder allows the elimination of the liquid phase and as a result prevents the clogging of the extrusion chamber. In the case of need for granulation of sensitive materials (for example pharmaceuticals not allowing the addition of any kind of agglomerating fluid or reacting strongly in the contact of the two phases), a process of compaction between rolls with different profiled surface was successfully applied. The developed high technologies and the resulting products thus represent a major contribution to environmental protection in the context of not only the work but also the communal environment.

Sign in / Sign up

Export Citation Format

Share Document