Harmonic Analysis of Engine Torque Due to Gas Pressure

E. S. TAYLOR; E. W. MORRIS

doi:10.2514/8.156

Harmonic Analysis of Engine Torque Due to Gas Pressure

Journal of the Aeronautical Sciences (Institute of the Aeronautical Sciences) ◽

10.2514/8.156 ◽

1936 ◽

Vol 3 (4) ◽

pp. 129-131 ◽

Cited By ~ 3

Author(s):

E. S. TAYLOR ◽

E. W. MORRIS

Keyword(s):

Harmonic Analysis ◽

Gas Pressure ◽

Engine Torque

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

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1563245 ◽

2003 ◽

Vol 125 (3) ◽

pp. 797-803 ◽

Cited By ~ 3

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.

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Critical Review of Porter’s Work on Engine Torque Harmonics

Volume 2: Instrumentation, Controls, and Hybrids; Numerical Simulation; Engine Design and Mechanical Development; Keynote Papers ◽

10.1115/icef2014-5437 ◽

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.

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