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SIMPLIFIED FLYWHEEL SPEED FLUCTUATION MONITORING AND CONTROL

IP.com Disclosure Number: IPCOM000006123D
Original Publication Date: 1991-Apr-01
Included in the Prior Art Database: 2001-Dec-05
Document File: 2 page(s) / 104K

Publishing Venue

Motorola

Related People

Robert W. Deutsch: AUTHOR

Abstract

U.S. patent 4,936,277 Deutsch et al describes a method for using the cyclic speed fluctuation to measure, diagnose and control the operation of an internal combustion engine. This system uses the vector multiplication of a predefined weighting vector by an instantaneous cylinder speed/power vector signal to obtain a scalar representing a parameter of the engine. The speed/power vector signal is obtained from a rotating toothed wheel position signal and comprises elapsed time of tooth periods for each cylinder cycle. A cylinder cycle consists of the angular period of the engine starting at a predefined time before top dead center (BTDC) and ending at a predetermined time after top dead center (ATDC). Parameters which can be measured are related to cylinder power, presence of knock and the existence of certain types of faults.

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MOTOROLA INC. Technical Developments Volume 12 April 1991

SIMPLIFIED FLYWHEEL SPEED FLUCTUATION MONITORING AND CONTROL

by Robert W. Deutsch

   U.S. patent 4,936,277 Deutsch et al describes a method for using the cyclic speed fluctuation to measure, diagnose and control the operation of an internal combustion engine. This system uses the vector multiplication of a predefined weighting vector by an instantaneous cylinder speed/power vector signal to obtain a scalar representing a parameter of the engine. The speed/power vector signal is obtained from a rotating toothed wheel position signal and comprises elapsed time of tooth periods for each cylinder cycle. A cylinder cycle consists of the angular period of the engine starting at a predefined time before top dead center (BTDC) and ending at a predetermined time after top dead center (ATDC). Parameters which can be measured are related to cylinder power, presence of knock and the existence of certain types of faults.

  The vector multiplication, while the engine is operating, requires significant processing power, particularly at high speeds. For example, at 5000 RPM, with 24 teeth per revolution, a three cylinder engine would require 2000 multiplications and additions per second to keep up with the vector processing. This represents a significant fraction of the capability of most controllers today without considering the other functions which must be completed in these modules.

  The simplification described subsequently would allow relatively simple hardware to perform the time consuming part of the control while retaining most of the flexibility described in patent 4,936,277.

  To simplify the vector multiplication process, the weighting vectors could consist of discrete values of ones and zeros. Hardware would pass through only tooth periods having a corresponding weighting vector component of one. The host processor would then sum those periods over a cylinder cycle to obtain a scalar parameter. To extract multiple scalar parameters, several discrete weighting vectors would be used.

0 MOtolOla. 1°C. 1991

  The figures on the next page show an example of how such a system would be constructed and used. A high data rate engine position signal could be derived from a dual sensor mon...