Cylinder Pressure Reconstruction From Crankshaft Speed Measurement in a Four-Stroke Single Cylinder Diesel Engine

2005 ◽  
Author(s):  
Dinu Taraza ◽  
Naeim A. Henein ◽  
Mangesh J. Gade ◽  
Walter Bryzik
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Angular Speed ◽  
Pressure Variation ◽  
Cylinder Pressure ◽  
Lumped Mass ◽  
Single Cylinder ◽  
Steady State Operation ◽  
Speed Fluctuation ◽  
Harmonic Components

In a single cylinder engine, the speed fluctuation during steady state operation of the engine is influenced only by the cylinder pressure variation, the engine friction and the dynamics of the crankshaft. This dependency is used to explore the capacity of the lumped mass model of the crankshaft to correctly represent its dynamics. Based on this model, the paper establishes the relationship between the cylinder pressure variation and the crankshaft speed fluctuation for steady state operation of the single cylinder diesel engine. Correlations are determined between the harmonic components of the tangential gas-pressure and the harmonic components of the angular speed of the free end of the crankshaft. These correlations are used to predict the angular speed variation of the crankshaft, when the cylinder pressure variation is known, or to reconstruct the cylinder pressure when the crankshaft speed fluctuation is known. The reverse calculation of the pressure variation from the measured crankshaft speed is strongly influenced by the elastic characteristics of the crankshaft. If the stiffness of the crankshaft is not accurately determined, the results are significantly distorted.

Modeling and validation of crankshaft speed fluctuations of a single-cylinder four-stroke diesel engine

2021 ◽  
pp. 095440702110262
Author(s):  
Mustafa Babagiray ◽  
Hamit Solmaz ◽  
Duygu İpci ◽  
Fatih Aksoy
Keyword(s):  
Diesel Engine ◽  
Dynamic Model ◽  
Moment Of Inertia ◽  
Mass Motion ◽  
Cylinder Pressure ◽  
Motion Equations ◽  
Single Cylinder ◽  
Mass Moment ◽  
Mass Moment Of Inertia ◽  
Speed Fluctuations

In this study, a dynamic model of a single-cylinder four-stroke diesel engine has been created, and the crankshaft speed fluctuations have been simulated and validated. The dynamic model of the engine consists of the motion equations of the piston, conrod, and crankshaft. Conrod motion was modeled by two translational and one angular motion equations, by considering the kinetic energy resulted from the mass moment of inertia and conrod mass. Motion equations involve in-cylinder gas pressure forces, hydrodynamic and dry friction, mass inertia moments of moving parts, starter moment, and external load moment. The In-cylinder pressure profile used in the model was obtained experimentally to increase the accuracy of the model. Pressure profiles were expressed mathematically using the Fourier series. The motion equations were solved by using the Taylor series method. The solution of the mathematical model was performed by coding in the MATLAB interface. Cyclic speed fluctuations obtained from the model were compared with experimental results and found compitable. A validated model was used to analyze the effects of in-cylinder pressure, mass moment of inertia of crankshaft and connecting rod, friction, and piston mass. In experiments for 1500, 1800, 2400, and 2700 rpm engine speeds, crankshaft speed fluctuations were observed as 12.84%, 8.04%, 5.02%, and 4.44%, respectively. In simulations performed for the same speeds, crankshaft speed fluctuations were calculated as 10.45%, 7.56%, 4.49%, and 3.65%. Besides, it was observed that the speed fluctuations decreased as the average crankshaft speed value increased. In the simulation for 157.07, 188.49, 219.91, 251.32, and 282.74 rad/s crankshaft speeds, crankshaft speed fluctuations occurred at rates of 10.45%, 7.56%, 5.84%, 4.49%, and 3.65%, respectively. The effective engine power was achieved as 5.25 kW at an average crankshaft angular speed of 219.91 rad/s. The power of friction loss in the engine was determined as 0.68 kW.

First Principle Based Control Oriented Gasoline Engine Model Including Lumped Cylinder Dynamics

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Ahmed Yar ◽  
A. I. Bhatti ◽  
Qadeer Ahmed
Keyword(s):  
Gasoline Engine ◽  
Angular Speed ◽  
Rigid Bodies ◽  
First Principle ◽  
Cylinder Pressure ◽  
Single Cylinder ◽  
Engine Model ◽  
Proposed Model ◽  
Engine Cylinder ◽  
Diagnostic Capabilities

A novel first principle based control oriented model of a gasoline engine is proposed which also carries diagnostic capabilities. Unlike existing control oriented models, the formulated model reflects dynamics of the faultless as well as faulty engine with high fidelity. In the proposed model, the torque production subsystem is obtained by integration of further two subsystems that is model of a single cylinder torque producing mechanism and an analytical gasoline engine cylinder pressure model. Model of a single cylinder torque producing mechanism is derived using constrained equation of motion (EOM) in Lagrangian mechanics. While cylinder pressure is evaluated using a closed form parametric analytical gasoline engine cylinder pressure model. Novel attributes of the proposed model include minimal usage of empirical relations and relatively wider region of model validity. Additionally, the model provides model based description of crankshaft angular speed fluctuations and tension in the rigid bodies. Capacity of the model to describe the system dynamics under fault conditions is elaborated with case study of an intermittent misfire condition. Model attains new capabilities based on the said novel attributes. The model is successfully validated against experimental data.

Steady-State Rigid-Body Dynamic Response of Cam-Follower Mechanisms

1994 ◽  
Author(s):  
Andi I. Mahyuddin ◽  
Ashok Midha
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Rigid Body ◽  
Angular Speed ◽  
Integration Scheme ◽  
Rigid Body Dynamic ◽  
Speed Variation ◽  
Cam Follower ◽  
Speed Fluctuation ◽  
Body Dynamic

Abstract The camshaft of a cam-follower mechanism experiences a position-dependent moment due to the force exerted on the cam by the follower, causing the angular speed of the camshaft to fluctuate. In this work, a method to expediently predict the camshaft speed fluctuation is developed. The governing equation of motion is derived assuming that the cam-follower system is an ideal one wherein all members are treated as rigid. An existing closed-form numerical algorithm is used to obtain the steady-state rigid-body dynamic response of a machine system. The solution considers a velocity-dependent moment; specifically, a resisting moment is modeled as a velocity-squared damping. The effects of flywheel size and resisting moment on camshaft speed fluctuation are studied. The results compare favorably with those obtained from transient response using a direct integration scheme. The analytical result also shows excellent agreement with the camshaft speed variation of an experimental cam-follower mechanism. The steady-state rigid-body dynamic response obtained herein also serves as a first approximation to the input camshaft speed variation in the dynamic analysis of flexible cam-follower mechanisms in a subsequent research.

Impact of Intake Induced Swirl on Combustion and Emissions on a Single Cylinder Diesel Engine

2016 ◽  
Author(s):  
Eduardo Barrientos ◽  
Ivan Bortel ◽  
Michal Takats ◽  
Jiri Vavra
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Operating Conditions ◽  
Common Rail ◽  
Injection System ◽  
Nox Emissions ◽  
Cylinder Pressure ◽  
Swirl Ratio ◽  
Single Cylinder ◽  
Optimal Values

Engine induced swirl improves mixing of fuel and air and at optimal values accelerates burn, improves the combustion stability and can decrease particulate matter (PM). However, swirl increases convective heat loss and cylinder charge loss and could increase nitrogen oxides (NOx) emissions. High intensity of swirl could impede flame development and increases emissions of total hydrocarbons (THC) and carbon monoxide (CO). Therefore, careful and smart selection of optimal swirl values is paramount in order to obtain beneficial impact on combustion and emissions performance. This study is conducted on a 0.5L single cylinder research engine with common rail (CR) diesel injection system, with parameters corresponding to modern engines of passenger cars. The engine has three separate ports in the cylinder head. The change of swirl ratio is defined by closing appropriate ports. There are three levels of swirl ratio under study — 1.7, 2.9 and 4.5, corresponding to low, medium and high swirl levels respectively. This study highlights the influence of intake induced swirl on combustion parameters and emissions. Assessed combustion parameters are, among others, heat release rate, cylinder pressure rise and indicated mean effective pressure. Assessed emissions are standard gaseous emissions and smoke, with emphasis on PM emissions. An engine speed of 1500 rpm was selected, which well represents common driving conditions of this engine size. Various common rail pressures are used at ambient inlet manifold pressure (without boost pressure) and at 1 bar boosted pressure mode. It is found that when the swirl level is increased, the faster heat release during the premixed combustion and during early diffusion-controlled combustion causes a quick increase in both in-cylinder pressure and temperature, thus promoting the formation of NOx. However, since swirl enhances mixing and potentially produces a leaning effect, PM formation is reduced in general. However, maximum peak temperature is lower for high swirl ratio and boosted modes due to the increase of heat transfer into cylinder walls. Furthermore, it is necessary to find optimal values of common rail pressures and swirl ratio. Too much mixing allows increase on PM, THC and CO emissions without decrease on NOx emissions in general. Common rail injection system provides enough energy to achieve good mixing during all the injection time in the cases of supercharged modes and high common rail pressure modes. Positive influence of swirl ratio is found at lower boost pressures, lower revolution levels and at lower engine loads. The results obtained here help providing a better understanding on the swirl effects on diesel engine combustion and exhaust emissions over a range of engine operating conditions, with the ultimate goal of finding optimal values of swirl operation.

Dynamic Analysis of the Crank Train in a Single Cylinder Diesel Engine Using a Lumped Parameter Method

2016 ◽  
Author(s):  
X. Y. Zhang ◽  
J. Guo ◽  
Zhang Wenping
Keyword(s):  
Diesel Engine ◽  
Dynamic Analysis ◽  
Internal Force ◽  
Parameter Method ◽  
Cylinder Pressure ◽  
Connecting Rod ◽  
Single Cylinder ◽  
Rotating Speed ◽  
Lumped Parameter ◽  
Lumped Parameter Method

The kinematic and dynamic behaviors of the crank train in a single cylinder diesel engine are analyzed in the paper. The crank train mechanism consists of four parts: a crank without counterweight, a connecting rod, a piston associated with a cylinder and two stops at both ends of a stroke. The dynamic model is developed using a lumped parameter method. The inertia of mass or moment are considered by an equivalent treatment in the centers of the piston pin, the crank pin, the main journal, respectively. The longitudinal deformations of the connecting rod are simulated by spring-damping elements, as well as the angular and bending deformations of the crank. As a result, it was possible to predict the effects of the component inertia of mass or moment and stiffness on the internal force and rotating speed of the crank under the cylinder pressure.

Effect of Injection Parameters and Strategy on the Noise From a Single Cylinder Direct Injection Diesel Engine

2011 ◽  
Author(s):  
Sukhbir Singh Khaira ◽  
Amandeep Singh ◽  
Marcis Jansons
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Injection Pressure ◽  
Combustion Noise ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Frequency Spectra ◽  
Single Cylinder ◽  
Direct Injection Diesel Engine ◽  
Injection Parameters

Acoustic noise emitted by a diesel engine generally exceeds that produced by its spark-ignited equivalent and may hinder the acceptance of this more efficient engine type in the passenger car market (1). This work characterizes the combustion noise from a single-cylinder direct-injection diesel engine and examines the degree to which it may be minimized by optimal choice of injection parameters. The relative contribution of motoring, combustion and resonance components to overall engine noise are determined by decomposition of in-cylinder pressure traces over a range of load, injection pressure and start of injection. The frequency spectra of microphone signals recorded external to the engine are correlated with those of in-cylinder pressure traces. Short Time Fourier Transformation (STFT) is applied to cylinder pressure traces to reveal the occurrence of motoring, combustion noise and resonance in the frequency domain over the course of the engine cycle. Loudness is found to increase with enhanced resonance, in proportion to the rate of cylinder pressure rise and under conditions of high injection pressure, load and advanced injection timing.

scholarly journals Development of a Marine Two-Stroke Diesel Engine MVEM with In-Cylinder Pressure Trace Predictive Capability and a Novel Compressor Model

2020 ◽  
Vol 8 (3) ◽  
pp. 204 ◽  
Author(s):  
Haosheng Shen ◽  
Jundong Zhang ◽  
Baicheng Yang ◽  
Baozhu Jia
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Spark Ignition Engine ◽  
Model Parameters ◽  
Analytic Model ◽  
Cylinder Pressure ◽  
Simulation Accuracy ◽  
Steady State Condition ◽  
Pressure Trace ◽  
D Model

In this article, to meet the requirements of marine engine room simulator on both the simulation speed and simulation accuracy, a mean value engine model (MVEM) for the 7S80ME-C9.2 marine two-stroke diesel engine was developed and validated in the MATLAB/Simulink environment. In consideration of the significant influence of turbocharger compressor on both the engine steady state performance and transient response, a novel compressor model (mass flow rate and isentropic efficiency model) based on a previous study carried out by the first author was proposed with the aim of achieving satisfactory simulation accuracy within the whole engine operating envelope. The predictive and extrapolative capability of the proposed compressor model was validated by carrying out simulation experiments and analyzing the simulation results under steady state condition and during transient process. To make the traditional MVEM capable of predicting in-cylinder pressure trace, the cylinder pressure analytic model proposed by Eriksson and Andersson for the four-stroke SI (spark ignition) engine was adapted to the 7S80ME-C9.2 marine two-stroke diesel engine based on the characteristic of in-cylinder pressure trace of this type of engine and then coupled to the MVEM developed in this paper. Since there is no need to solve any differential equation as it is done in the 0-D model, the advantage of MVEM in running speed is not impaired. For achieving satisfactory simulation accuracy by using the analytic model, the model parameters were calibrated elaborately by using engine measured data and a 0-D model and the relevant tuning procedure was discussed in detail.

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