Critical Review of Porter’s Work on Engine Torque Harmonics

2014 ◽  
Author(s):  
Samuel Doughty
Keyword(s):  
Torsional Vibration ◽  
Critical Review ◽  
Gas Pressure ◽  
Ic Engine ◽  
Excitation Functions ◽  
Consistent System ◽  
Engine Torque ◽  
System Of Units ◽  
The Us ◽  
Data Tables

The classic 1943 paper by F.P. Porter on IC engine torque harmonics is best known for its data tables related to the gas pressure torques. However, it also presents Porter’s work on the inclusion of inertial and gravitational torques as excitation functions for torsional vibration. This latter part is relatively obscure because (1) it is presented without any supporting analysis, (2) a number of the quantities involved are not clearly defined, and (3) Porter’s presentation is entirely tied to the US Customary Units system. The present paper explains Porter’s results, with clear definitions of all terms and an appropriate system sketch, and provides a physical motivation for each of his terms in a framework suitable for use with any consistent system of units.

Modeling of nonlinear torsional vibration of the automotive powertrain

2016 ◽  
Vol 24 (9) ◽  
pp. 1774-1786 ◽  
Author(s):  
Sérgio J Idehara ◽  
Fernando L Flach ◽  
Douglas Lemes
Keyword(s):  
Natural Frequency ◽  
Torsional Vibration ◽  
Degrees Of Freedom ◽  
Front Wheel ◽  
Torsional Stiffness ◽  
Bench Test ◽  
Passenger Car ◽  
Engine Torque ◽  
Friction Moment ◽  
Wheel Drive

A vibration model of the powertrain can be used to predict its dynamic behavior when excited by fluctuations in the engine torque and speed. The torsional vibration resulting from torque and speed fluctuations increases the rattle noise in the gearbox and it should be controlled or minimized in order to gain acceptance by clients and manufactures. The fact that the proprieties of the torsional damper integrated into the clutch disc alter the dynamic characteristic of the system is important in the automotive industry for design purposes. In this study, bench test results for the characteristics of a torsional damper for a clutch system (torsional stiffness and friction moment) and powertrain torsional vibration measurements taken in a passenger car were used to verify and calibrate the model. The adjusted model estimates the driveline natural frequency and the time response vibration. The analysis uses order tracking signal processing to isolate the response from the engine excitation (second-order). It is shown that a decrease in the stiffness of the clutch disc torsional damper lowers the natural frequency and an increase in the friction moment reduces the peak amplitude of the gearbox torsional vibration. The formulation and model adjustment showed that a nonlinear model with three degrees of freedom can represent satisfactorily the powertrain dynamics of a front-wheel drive passenger car.

Identification of firefly algorithm-based fluctuation coefficient of the exciting torque for vehicle driveline

2018 ◽  
Vol 233 (2) ◽  
pp. 317-326
Author(s):  
Qiaobin Liu ◽  
Wenku Shi ◽  
Zhiyong Chen
Keyword(s):  
Torsional Vibration ◽  
Firefly Algorithm ◽  
Vibration Response ◽  
Theoretical Modelling ◽  
Lumped Mass ◽  
Mass Model ◽  
Engine Torque ◽  
Lumped Mass Model ◽  
Vibration Performance ◽  
Engine Excitation

The unbalanced excitation force and torque generated by an engine that resonate with the natural frequency of drivetrain often causes vibration and noise problems in vehicles. This study aims to comprehensively employ theoretical modelling and experimental identification methods to obtain the fluctuation coefficients of engine excitation torque when a car is in different gear positions. The inherent characteristics of the system are studied on the basis of the four-degree-of-freedom driveline lumped mass model and the longitudinal dynamics model of vehicle. The correctness of the model is verified by torsional vibration test. The second order's engine torque fluctuation coefficients are identified by firefly algorithm according to the curves of flywheel speed in different gears under the acceleration condition of the whole open throttle. The torque obtained by parameter identification is applied to the model, and the torsional vibration response of the system is analysed. The influence of the key parameters on the torsional vibration response of the system is investigated. The study concludes that proper reduction of clutch stiffness can increase clutch damping and half-axle rigidity, which can help improve the torsional vibration performance of the system. This study can provide reference for vehicle drivetrain modelling and torsional vibration control.

Torsional Vibration Analysis of a Hydrodynamic Split Torque Transmission

1967 ◽  
Vol 89 (4) ◽  
pp. 605-610
Author(s):  
D. A. Klokkenga
Keyword(s):  
Experimental Data ◽  
Torsional Vibration ◽  
Vibration Analysis ◽  
Equations Of Motion ◽  
Planetary Gear ◽  
Torque Converter ◽  
Transmission System ◽  
Engine Torque ◽  
Lagrange’S Equation ◽  
Torque Transmission

The steady-state torsional vibration for one mode of an engine transmission system was analyzed, and the analysis was verified by experimental data. The engine transmission system included a diesel engine, torque divider which consisted of a fixed housing, single-stage torque converter and a planetary gear set, and a dynamometer. The equations of motion are derived by an energy method (LaGrange’s equation) and a numerical solution of these equations is obtained with the aid of a digital computer. The analytical and experimental results agree when empirical values for torque converter damping are used.

scholarly journals A critical review of synthetic chemicals in surface waters of the US, the EU and China

2019 ◽  
Vol 131 ◽  
pp. 104994 ◽  
Author(s):  
Wendi Fang ◽  
Ying Peng ◽  
Derek Muir ◽  
Jun Lin ◽  
Xiaowei Zhang
Keyword(s):  
Surface Waters ◽  
Critical Review ◽  
Synthetic Chemicals ◽  
The Us ◽  
The Eu

Design Charts for Self-Excited Whirling Critical Speeds

1982 ◽  
Vol 26 (03) ◽  
pp. 190-208
Author(s):  
H. P. Yagoda ◽  
J Ketchman
Keyword(s):  
Flexural Rigidity ◽  
Design Parameters ◽  
Rotatory Inertia ◽  
Consistent System ◽  
Critical Speeds ◽  
Design Charts ◽  
System Of Units ◽  
Wide Range ◽  
Gyroscopic Effects ◽  
Hand Calculator

Employing a generalized tailshaft model of the propulsion system, design charts are constructed for rapidly estimating self-excited whirling critical speeds of the shafting system over a wide range of design parameters. These design chart estimates may be refined to any desired accuracy by a program developed for a programmable hand calculator. The analysis includes propeller mass and rotatory inertia, propeller gyroscopic effects, shaft mass and flexural rigidity, and partial fixity of the line shafting at the forward bearing. Entrained water may be included as a proportion of the propeller mass and inertia. The nondimensional form of the design charts offers several advantages, for example, the option of employing any consistent system of units, or to quickly assess the sensitivity of the critical whirling speeds to design parameters of the system. Comparison of results with other methods is very favorable.

Statistical Correlation Between the Crankshaft’s Speed Variation and Engine Performance—Part II: Detection of Deficient Cylinders and Mean Indicated Pressure Calculation

2003 ◽  
Vol 125 (3) ◽  
pp. 797-803 ◽  
Author(s):  
D. Taraza
Keyword(s):  
Phase Angle ◽  
Harmonic Component ◽  
Engine Performance ◽  
Statistical Correlation ◽  
Gas Pressure ◽  
Order Component ◽  
Engine Torque ◽  
Torque Vector ◽  
Rigid Body Model ◽  
Order Components

The goal of this two-part paper is to develop a methodology using the variation of the measured crankshaft speed to calculate the mean indicated pressure (MIP) of a multicylinder engine and to detect cylinders that are lower contributors to the total engine output. The statistical model of a harmonic component of the engine torque developed in the first part of the paper is used to achieve this goal. The analysis of the half-order components of the gas pressure torque permits to identify distinct phase angle domains of the resultant torque vector that are specific for the deficiencies of given cylinders. Based on the rigid-body model of the crankshaft, these phase angle domains are correlated to the phase angle domains of the half-order component of the crankshaft speed. Then, the phase angle of the half-order component of the measured crankshaft speed will identify the deficient cylinder. The amplitude of the first major harmonic component of the measured crankshaft speed is correlated to the corresponding harmonic order of the gas pressure torque and is used to calculate the MIP of the engine. The accuracy limits of this “software dynamometer” are also presented.

Design of An IC Engine Torque Estimator Using Unknown Input Observer

1999 ◽  
Vol 121 (3) ◽  
pp. 487-495 ◽  
Author(s):  
Yong Wha Kim ◽  
Giorgio Rizzoni ◽  
Yue-Yun Wang
Keyword(s):  
Combustion Engine ◽  
Low Cost ◽  
Angular Position ◽  
Pressure Sensors ◽  
Sufficient Conditions ◽  
Engine Performance ◽  
Unknown Input ◽  
Ic Engine ◽  
Engine Torque ◽  
Necessary And Sufficient

The torque produced by each combustion in an engine is one of the most important indices tied to internal combustion engine performance. In this paper, an approach is investigated to estimate engine torque. Instead of employing expensive and delicate combustion pressure sensors to directly measure indicated pressure in each cylinder, unknown input observers are exploited to estimate cylinder indicated torque using one or more low-cost measurements of crankshaft angular position. Necessary and sufficient conditions for the existence of such torque estimators for multi-cylinder engines are presented in the paper; these include the number of angular position sensors required and their suggested placement. Model reduction issues and the number of measurements required to obtain an acceptable estimate are also considered. The approach is applied to a six-cylinder industrial diesel engine.

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