Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – With indicator or control of power plant
Reexamination Certificate
2001-05-02
2003-07-08
Vo, Hieu T. (Department: 3747)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
With indicator or control of power plant
C701S114000, C701S115000, C123S406620
Reexamination Certificate
active
06591184
ABSTRACT:
BACKGROUND OF THE INVENTION
This application is based on Application No. 2000-317930, filed in Japan on Oct. 18, 2000, the contents of which are hereby incorporated by reference.
The present invention generally relates to a cylinder identifying system for an internal combustion engine mounted on an automobile or a motor vehicle. More particularly, the present invention is concerned with a cylinder identifying system for an internal combustion engine which system is designed for identifying discriminatively individual cylinders of the internal combustion engine within a short time upon starting of operation of the engine to thereby allow a fuel injection control and an ignition control for the engine to be speedily carried out on a cylinder-by-cylinder basis.
DESCRIPTION OF RELATED ART
As the hitherto known or conventional cylinder identifying system of the sort mentioned above, there can be mentioned the one which is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 146992/1994 (JP-A-6-146992). In the cylinder identifying system described in this publication, a crank angle pulse signal generated in synchronism with rotation of a crank shaft of the internal combustion engine and a cam pulse signal generated in synchronism with rotation of a cam shaft which is operatively coupled to the crank shaft and rotated at a speed ratio of ½ relative to that of the crank shaft are employed for detecting the angle of rotation or angular position of the crank shaft on the basis of which engine operation controls such as a fuel injection control, an ignition control, etc. are performed for the individual cylinders of the engine.
For generating the crank angle pulse signal, a crank angle sensor is provided which is constituted by a ring gear (or toothed wheel) mounted in a coaxial relation with the crank shaft and having an outer periphery formed with projections or teeth and an electromagnetic pickup device disposed in opposition to the outer periphery of the ring gear for generating pulses in response to the individual projections or teeth, respectively. The crank angle pulse signal is derived from the output signal of the electromagnetic pickup device and includes sequentially a series of pulse trains, wherein each pulse train corresponds to a predetermined angle of rotation of the crank shaft or a predetermined angular range delimited by a reference position.
On the other hand, the pulse generator for generating the cam pulse signal is so arranged that the numbers of pulses contained in the cam pulse signals, respectively, differ from one another for the crank angle pulse signals SGT generated successively each over a predetermined crank angle range corresponding to given one of the engine cylinders. Thus, on the basis of combination of the numbers of pulses contained in the cam pulse signals generated within a preceding range (during a preceding period, to say in another way) and within a current range (during a current period), it is certainly possible to identify the individual cylinder sets as well as particular or specific position(s) in the crank angle pulse signal.
However, in the conventional cylinder identifying system for the internal combustion engine, the combinations of the pulse numbers generated at the specific positions are limited to three values, i.e., “0”, “1” and “2”. Accordingly, in the case of a six-cylinder engine, it is impossible to identify discriminatively any given cylinder on the basis of only the combination of the numbers of pulses generated during two periods (or over two ranges), respectively.
Further, since the specific position and the cylinders are determined discriminatively on the basis of the combination of the numbers of pulses generated during the preceding period and the current period, respectively, the cylinder identification is rendered impossible in the case where the end point of the current period does not coincide with the specific position.
By way of example, in the case of the four-cylinder engine, the range of crank angles corresponding or equivalent to one period is set to be 90° CA (i.e., 90 degrees in terms of the crank angle or CA in short). Consequently, the cylinder identification processing can be completed within a period corresponding to rotation of the engine for 180° CA at the shortest although it depends on the crank angle at which the engine was stopped in the preceding operation. However, there will arise such situation that the cylinder identification can not be completed until the engine has rotated over 360° CA at maximum, which of course depends on the crank angle at which the engine was stopped in the preceding operation. In the latter case, starting of the engine operation from the stopped state requires a lot of time, needless to say.
Another cylinder identifying system for the internal combustion engine is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 311146/1999 (JP-A-11-311146). In this known cylinder identifying system, a crank angle pulse signal (POS) including pulse trains each having a duration or a period which corresponds to a predetermined crank angle range (10° CA) and having a reference position which corresponds to a tooth absent or dropout location in an outer peripheral projection or tooth array of a ring gear, an angle reference signal (REF) indicating an angle reference differing from the reference position mentioned above, and a cam pulse signal (CAM).
In this cylinder identifying system known heretofore, the cam pulse signal generating unit is so arranged that the numbers of pulses generated during successive subperiods, respectively, which are defined by dividing a corresponding crank angle period for each engine cylinder differ from each other.
In the system mentioned above, an electronic control unit which may be constituted by a microcomputer or the like is so designed as to respond to detection of the angle reference signal REF to thereby divide a range or period defined between a detected start point (leading edge) and an end point (trailing edge) of the angle reference signal REF into a plurality of subperiods (e.g. two subperiods).
The durations of the subperiods can be measured with the crank angle pulse signal POS. On the other hand, an array of projections or teeth formed on and along the outer periphery of a rotatable plate mounted coaxially with the cam shaft is previously so arranged that the cam pulse signals CAM generated during the subperiods, respectively, differ from each other in respect to the pulse number.
More specifically, the numbers of pulses of the cam pulse signals CAM generated during the subperiods are previously set to two different values (e.g. “1” and “0”), respectively, wherein the cylinder identification can be realized on the basis of combination of the numbers of the cam pulses generated during the subperiods each extending from a given angle reference signal REF to a succeeding angle reference signal REF.
Also in this case, a period extending between the angle reference signals REF is divided into a plurality of subperiods after detection of the angle reference signals REF and then the cylinder identification is carried out on the basis of combination of the numbers of pulses generated during the plural subperiods, respectively. Thus, the cylinder identification can be started only after the generation of the angle reference signals REF.
Such being the circumstances, also in the cylinder identifying system disclosed in Japanese Unexamined Patent Application Publication No. 311146/1999, one period which corresponds to revolution of the engine for 180° CA is required for completing the cylinder identification processing at the shortest although it depends on the crank angle at which the engine was stopped in the preceding operation thereof, similarly to the case of the cylinder identifying system disclosed in Japanese Unexamined Patent Application Publication No. 146992/1994. In the worst case, the cylinder identification can not be completed until the engine has been rotated over 360° CA
Hashimoto Atsuko
Ohuchi Hirofumi
Yonezawa Shiro
Mitsubishi Denki & Kabushiki Kaisha
Vo Hieu T.
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