Measurement of the instantaneous in-cylinder pressure of reciprocating compressors using the connecting rod strain

Piston assembly friction measurement has been carried out on a single cylinder gasoline engine using the IMEP (indicated mean effective pressure) method at realistic engine speeds and loads without any major engine modifications. Instantaneous and mean piston assembly friction were measured under motored and fired conditions at different lubricant temperatures. The forces acting on the piston assembly were carefully determinated by measuring the cylinder pressure, crankshaft angular velocity and strain in the connecting rod. The difference between the resulting gas pressure, inertia and connecting rod axial forces acting on the piston yields the piston assembly friction. To achieve this with confidence, an advanced instrumentation, telemetry and data acquisition system was designed and developed, giving special attention to the synchronisation and simultaneous sampling of analogue and digital channels. Experiments are reported for piston assembly friction at a range of engine operating conditions with different lubricant formulations, with and without a friction modifier.

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

ASME 2016 Internal Combustion Engine Fall Technical Conference ◽

10.1115/icef2016-9337 ◽

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.

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DYNAMIC AND STRUCTURAL ANALYSIS OF THE PISTON AND CONNECTING ROD OF A ENGINE FUELED BY DIESEL OIL AND ETHANOL USING IN-CYLINDER PRESSURE DATA

10.20906/cps/cilamce2015-0235 ◽

2015 ◽

Author(s):

Alex de Oliveira ◽

José Ricardo Sodré ◽

André Marcelino Morais

Keyword(s):

Structural Analysis ◽

Diesel Oil ◽

Cylinder Pressure ◽

Pressure Data ◽

Connecting Rod

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Experimental Evaluation of Piston-Assembly Friction Under Motored and Fired Conditions in a Gasoline Engine

Journal of Tribology ◽

10.1115/1.1924459 ◽

2004 ◽

Vol 127 (4) ◽

pp. 826-836 ◽

Cited By ~ 36

Author(s):

Riaz A Mufti ◽

Martin Priest

Keyword(s):

Gasoline Engine ◽

Operating Conditions ◽

Cylinder Pressure ◽

Connecting Rod ◽

Friction Modifier ◽

Indicated Mean Effective Pressure ◽

Axial Forces ◽

The Difference ◽

Digital Channels ◽

Piston Assembly

Piston-assembly friction measurement has been carried out on a single-cylinder gasoline engine using the IMEP (indicated mean effective pressure) method at realistic engine speeds and loads without any major engine modifications. Instantaneous and mean piston-assembly friction were measured under motored and fired conditions at different lubricant temperatures. The forces acting on the piston assembly were carefully determined by measuring the cylinder pressure, crankshaft angular velocity, and strain in the connecting rod. The difference between the resulting gas pressure, inertia, and connecting rod axial forces acting on the piston yields the piston-assembly friction. To achieve this with confidence, an advanced instrumentation, telemetry, and data acquisition system was designed and developed, giving special attention to the synchronization and simultaneous sampling of analog and digital channels. Experiments are reported for piston-assembly friction at a range of engine operating conditions with different lubricant formulations, with and without a friction modifier.

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Kinematics of an Articulated Connecting Rod and its Effect on Simulated Compression Pressures and Port Timings

Volume 2: Emissions Control Systems; Instrumentation, Controls, and Hybrids; Numerical Simulation; Engine Design and Mechanical Development ◽

10.1115/icef2017-3670 ◽

2017 ◽

Cited By ~ 1

Author(s):

Kelsey Fieseler ◽

Timothy J. Jacobs ◽

Mark Patterson

Keyword(s):

Equations Of Motion ◽

Good Method ◽

Cylinder Pressure ◽

Pressure Data ◽

Connecting Rod ◽

Piston Motion ◽

Exhaust Port ◽

Port Opening ◽

Cylinder Compression ◽

Crank Mechanism

This study discusses the motion of the articulated connecting rod of an integral-engine compressor and the effect of the kinematics on in-cylinder pressure and port timings. A piston position modeling technique based on kinematics and engine geometry is proposed in order to improve the accuracy of simulated in-cylinder compression pressures. Many integral-engine compressors operate with an articulated connecting rod. For this type of engine-driven compressor, two power pistons share a crank throw with the compressor. The hinge pins that attach the power piston connecting rods to the crank are offset, causing the piston locations for each cylinder to be out of phase with each other. This causes top dead center to occur at different crank angles, alters the geometric compression ratio, and also changes the port timings for each cylinder. In this study, the equations of motion for the pistons of the four possible compressor/piston configurations of a Cooper-Bessemer GMW are developed. With the piston profiles, the intake and exhaust port timings were determined and compared to those of a slider-crank mechanism. The piston profile was then inputted into GT-POWER, an engine modeling software developed by Gamma Technologies, in order to obtain an accurate simulation match to the experimental in-cylinder pressure data collected from a Cooper-Bessemer GMWH-10C. Assuming the piston motion of an engine with an articulated connecting rod is similar to a slider-crank mechanism can create a difference in port timings. The hinge pin offset creates asymmetrical motion about 180°aTDC, causing the port timings to also be asymmetrical about this location. The largest differences are shown in the intake port opening of about 10° and a difference in exhaust port opening of about 7° when comparing the motion of the correct configuration to the motion of a slider-crank mechanism. It is shown that properly calculating the piston motion profiles according to the crank articulation and engine geometry provides a good method of simulating in-cylinder pressure data during the compression stroke.

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A Dynamic Analysis of Reciprocating Compressor Transmission Mechanism with Joint Clearance

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.226-228.641 ◽

2012 ◽

Vol 226-228 ◽

pp. 641-645 ◽

Cited By ~ 2

Author(s):

Hai Yang Zhao ◽

Min Qiang Xu ◽

Jin Dong Wang ◽

Gui Juan Chen

Keyword(s):

Dynamic Behavior ◽

Influence Factors ◽

Contact Forces ◽

Transmission Mechanism ◽

Joint Clearance ◽

Prototype Model ◽

Reciprocating Compressor ◽

Cylinder Pressure ◽

Connecting Rod ◽

Pressure Load

The dynamic behavior of a reciprocating compressor transmission mechanism with joint clearance is studied in this paper. A transmission mechanism virtual prototype model is built under software ADAMS. Revolute joint between connecting rod and crosshead pin is modeled with clearance by contact model based on the so called Impact-function, and four processes of cylinder pressure load is simulated by the IF function. Cylinder pressure load, amplitude of joint clearance, crank speed and flexibility of connecting rod is taken as influence factors. Four different cases were simulated. Joint contact forces, accelerations of compressor block and journal centre path are used to analyze the dynamic behavior. The presented results show that these factors play a significant role of dynamic behavior of mechanisms.

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Kinematics of an Articulated Connecting Rod and Its Effect on Simulated Compression Pressures and Port Timings

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4039831 ◽

2018 ◽

Vol 140 (9) ◽

Author(s):

Kelsey Fieseler ◽

Timothy J. Jacobs ◽

Mark Patterson

Keyword(s):

Equations Of Motion ◽

Good Method ◽

Cylinder Pressure ◽

Pressure Data ◽

Connecting Rod ◽

Piston Motion ◽

Exhaust Port ◽

Port Opening ◽

Cylinder Compression ◽

Crank Mechanism

This study discusses the motion of the articulated connecting rod of an integral-engine compressor and the effect of the kinematics on in-cylinder pressure and port timings. A piston position modeling technique based on kinematics and engine geometry is proposed in order to improve the accuracy of simulated in-cylinder compression pressures. Many integral-engine compressors operate with an articulated connecting rod. For this type of engine-driven compressor, two power pistons share a crank throw with the compressor. The hinge pins that attach the power piston connecting rods to the crank are offset, causing the piston locations for each cylinder to be out of phase with each other. This causes top dead center (TDC) to occur at different crank angles, alters the geometric compression ratio, and also changes the port timings for each cylinder. In this study, the equations of motion for the pistons of the four possible compressor/piston configurations of a Cooper-Bessemer GMW are developed. With the piston profiles, the intake and exhaust port timings were determined and compared to those of a slider-crank mechanism. The piston profile was then inputted into GT-POWER, an engine modeling software developed by Gamma Technologies, in order to obtain an accurate simulation match to the experimental in-cylinder pressure data collected from a Cooper-Bessemer GMWH-10C. Assuming the piston motion of an engine with an articulated connecting rod is similar to a slider-crank mechanism can create a difference in port timings. The hinge pin offset creates asymmetrical motion about 180°aTDC, causing the port timings to also be asymmetrical about this location. The largest differences are shown in the intake port opening of about 10 deg and a difference in exhaust port opening of about 7 deg when comparing the motion of the correct configuration to the motion of a slider-crank mechanism. It is shown that properly calculating the piston motion profiles according to the crank articulation and engine geometry provides a good method of simulating in-cylinder pressure data during the compression stroke.

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