How Chemistry Controls Engine Design

2001 ◽  
Author(s):  
Patrick F. Flynn
Keyword(s):  
Compression Ratio ◽  
Close Agreement ◽  
Exhaust Emissions ◽  
Chemical Analyses ◽  
Fuel Oxidation ◽  
Overall Design ◽  
Engine Design ◽  
Oxidation Chemistry

Abstract A review of empirical engine data that exhibit the limits of the chemistry of fuel oxidation in engines is presented. These data have been compared to analyses using up to date fuel oxidation chemical analyses programs and shown to be in close agreement. The constraints caused by the fuel oxidation chemistry limitations are key determinants of the engine’s overall design, determining allowed intake conditions, fuel-air ratios, compression ratio requirements, and the need for such ancillary devices as those for exhaust emissions aftertreatment.

Paper 4: The Effect of Combustion Chamber Shape and Other Engine Design Factors on Exhaust Emissions

1968 ◽  
Vol 183 (5) ◽  
pp. 133-144 ◽  
Author(s):  
P. L. Dartnell ◽  
C. L. Goodacre ◽  
P. V. Lamarque
Keyword(s):  
Combustion Chamber ◽  
Engine Performance ◽  
Exhaust System ◽  
Exhaust Emissions ◽  
Intake Manifold ◽  
Valve Timing ◽  
Mixture Formation ◽  
Engine Design ◽  
Basic Engine ◽  
Design Factors

A Heron combustion chamber engine of 2 litre capacity has been utilized to investigate the effect of combustion chamber shape, increased mixture movement, valve timing, mixture formation, and reaction in the exhaust system on engine performance and level of exhaust emissions using the seven-mode U.S. Federal cycle. Such factors as carburettor weakening and limitation of intake manifold vacuum during overrun have been included in this investigation, and it has been shown that it is possible to reduce exhaust emissions and also satisfy the current U.S. requirements with an engine giving acceptable performance, improved economy, and unaffected reliability. Much of the information reported may be negative in terms of improvement to exhaust emissions by detailed engine design. Nevertheless, some positive conclusions have been reached as a result of this work, and it is hoped that this will draw forth more informed discussion than the authors have been able to assemble from the work attempted with one basic engine.

Prediction of Peak Cylinder Pressure Variations Over Varying Inlet Air Condition of Compression-Ignition Engine

2005 ◽  
Author(s):  
Gong Chen
Keyword(s):  
Air Temperature ◽  
Compression Ratio ◽  
Design Parameters ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Compression Ignition Engine ◽  
Engine Design ◽  
Peak Cylinder Pressure ◽  
Temperature And Pressure ◽  
Cylinder Compression

Peak cylinder pressure of a compression-ignition engine can be affected by engine inlet air condition such as its temperature and pressure. The variation of peak cylinder pressure due to varying inlet air temperature and pressure is analytically studied in this paper. An analytical model is developed and thus the variations of peak cylinder pressure can be predicted along with inlet air temperature or pressure varying. It is indicated that cylinder compression ratio (CR) and intake air boost ratio (pm0/pi0) play significant roles in affecting the variation of peak cylinder pressure over inlet air temperature and pressure, and the pressure variation is proportional to CRk and pm0/pi0. The predicted results are compared to those from engine experiments, and show a close agreement. The prediction also includes the investigation of the variation in peak cylinder pressure due to varying the cylinder TDC volume. Results from the analytical studies are presented and show that the change in pmax versus a change in the volume is also affected by compression ratio. This indicates that for a certain change in the clearance volume, a higher compression-ratio configuration would produce a greater change in pmax than a lower compression-ratio would with the rest of the engine design parameters remaining unchanged.

scholarly journals The effect of compression ratio on exhaust emissions from a PCCI diesel engine

2007 ◽  
Vol 48 (11) ◽  
pp. 2918-2924 ◽  
Author(s):  
O. Laguitton ◽  
C. Crua ◽  
T. Cowell ◽  
M.R. Heikal ◽  
M.R. Gold
Keyword(s):  
Diesel Engine ◽  
Compression Ratio ◽  
Exhaust Emissions

Design and Analysis of a Lightweight Polygon Engine

2013 ◽  
Author(s):  
Adam N. Clark ◽  
Kevin R. Anderson ◽  
Clifford M. Stover ◽  
Stephen L. Cunningham ◽  
Martin Stuart
Keyword(s):  
Compression Ratio ◽  
Weight Ratio ◽  
Kinematic Modeling ◽  
Gasoline Engines ◽  
Analysis And Design ◽  
Current Trends ◽  
Engine Design ◽  
Piston Speed ◽  
Engine Systems ◽  
Plane Polygon

Current trends in engine design have pushed the state-of-the-art regarding high power-to-weight ratio gasoline engines. Newly developed engine systems have a power to weight ratio near 1 hp per pound. The engine configuration presented herein makes it possible to package a large number of power producing pistons in a small volume resulting in a power to weight ratio near 2 hp per pound, which have never before been realized in a production engine. The analysis and design of a lightweight, two-stroke, 6 side, in-plane, polygon engine having a geometric compression ratio of 15.0, actual compression ratio of 8.8 and piston speed of 3500 ft/min are presented in this investigation. Power output, kinematic modeling, and weight estimates are presented.

scholarly journals Low-Speed Marine Diesel Engine Modeling for NOx Prediction in Exhaust Gases

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4442
Author(s):  
Branko Lalić ◽  
Andrijana Poljak ◽  
Gojmir Radica ◽  
Antonija Mišura
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Nitrogen Dioxide ◽  
Nitrogen Oxide ◽  
Fuel Consumption ◽  
Compression Ratio ◽  
Fuel Injection ◽  
Nitrogen Monoxide ◽  
Exhaust Emissions ◽  
Injection Timing

Knowing the process of generating exhaust emissions and the determination of influential parameters are important factors in improving two-stroke slow-speed marine engines, particularly for further reductions in fuel consumption and stringent regulations on the limitation of nitrogen oxide emissions. In this article, a model of a marine low-speed two-stroke diesel engine has been developed. Experimental and numerical analyses of the nitrogen monoxide formations were carried out. When measuring the concentration of nitrogen oxides in the exhaust emissions, the amount of nitrogen dioxide (NO2) is usually measured, because nitrogen monoxide is very unstable, and due to the large amount of oxygen in the exhaust gases, it is rapidly converted into nitrogen dioxide and its amount is included in the total emission of nitrogen oxides. In this paper, the most significant parameters for the formation of nitrogen monoxide have been determined. Model validation was performed based on measured combustion pressures, engine power, and concentrations of nitrogen oxides at 50% and 75% of maximum continuous engine load. The possibilities of fuel consumption optimization and reduction in nitrogen monoxide emissions by correcting the injection timing and changing the compression ratio were examined. An engine model was developed, based on measured combustion pressures and scavenging air flow, to be used on board by marine engineers for rapid analyses and determining changes in the concentration of nitrogen oxides in exhaust emissions. The amount of nitrogen oxide in exhaust emissions is influenced by the relevant features described in this paper: fuel injection timing and engine compression ratio. The presented methodology provides a basis for further research about the simultaneous impact of changing the injection timing and compression ratio, exhaust valve opening and closing times, as well as the impact of multiple fuel injection to reduce consumption and maintain exhaust emissions within the permissible limits.

The Deviation Function Method of Rotary Engine Design by Geometric Parameters

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Sarah Warren Rose ◽  
Daniel C. H. Yang
Keyword(s):  
Compression Ratio ◽  
Design Method ◽  
Geometric Parameters ◽  
Performance Criteria ◽  
Engine Operation ◽  
Deviation Function ◽  
Rotary Engine ◽  
Engine Design ◽  
K Factor ◽  
Wankel Engine

Rotary engines require seals inserted into each rotor apex to maintain contact with the housing and prevent leaks during internal combustion. These seals are called apex seals and their effectiveness directly influences the engine operation and efficiency. The deviation function (DF) method of rotary engine design has several advantages over the conventional design method with regard to the apex seals, and also finds many more possibilities. The DF method can be used to incorporate the profile of the apex seal into the design process and the rotor profile itself. In the DF method, the seal profile is used as a generating curve and the housing bore profile is a generated curve. The housing is conjugate to the apex seal, and therefore conforms to the seal profile, unlike the conventional rotary engine. Another advantage the DF method has over the conventional method is that different apex seal profiles can be used, resulting in a larger variety of rotary engine designs. This paper introduces the DF method of rotary engine design and selection by the geometric parameters rotor radius, R, and eccentricity, l. In conventional rotary (Wankel) engine design, these parameters are used as a ratio called the K factor. The K factor uniquely identifies a conventional rotary engine profile and is therefore used to associate performance criteria such as displacement, compression ratio, and apex sealing. The DF method can be used to employ the same ratio as a selection tool. Instead of a single profile for each K factor, there is a range of possible DF-designed engine profiles associated with each R/l ratio. The resulting design flexibility is shown using two example deviation functions and the design criteria swept area and maximum theoretical compression ratio. Furthermore, the R/l ratio is not an indication of apex sealing effectiveness because the DF method of rotary engine design and selection separates the engine profile geometry from the apex seal geometry. An apex sealing index is presented to show how the DF method can be used to quantify, analyze, and improve apex sealing.

Prediction of Peak Cylinder Pressure Variations Over Varying Inlet Air Condition of Compression-Ignition Engine

2006 ◽  
Vol 129 (2) ◽  
pp. 589-595 ◽  
Author(s):  
Gong Chen
Keyword(s):  
Air Temperature ◽  
Compression Ratio ◽  
Simplified Model ◽  
Compression Ignition ◽  
Cylinder Pressure ◽  
Compression Ignition Engine ◽  
Engine Design ◽  
Peak Cylinder Pressure ◽  
Temperature And Pressure ◽  
Cylinder Compression

Peak cylinder pressure (pmax) of a compression-ignition engine can be affected by the engine inlet air condition, such as its inlet air temperature (Ti) and pressure (pi). The variation of peak cylinder pressure due to varying inlet air temperature or pressure is analytically studied. A model is developed and simplified, and thus the variations of pmax can be predicted along with varying inlet air temperature or pressure. The analysis and prediction indicate that cylinder active compression ratio (CR) and intake air boost ratio (pm0∕pi0) play relatively significant roles in affecting the variation of pmax over inlet air temperature and pressure, and the pressure variation is proportional to CRk and ratio pm0∕pi0. Comparison between the predicted results using the simplified model and those from engine experiments shows a close agreement in both the trend and magnitude. The investigation and prediction also include modeling the variation in pmax due to varying the cylinder TDC clearance volume (Vc). The simplified model is presented and shows that the change in pmax versus varying Vc also depends on the cylinder compression ratio. It is indicated that for a certain change in the clearance volume, a higher compression-ratio configuration would produce a greater change in pmax than a lower one does, especially as the rest of the engine design and operating parameters remain unchanged.

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