JP2005256616A - Method for angle correction of rotation angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for angle correction in a rotation angle detector of an internal combustion engine for correctly detect event timing designated as an angle of rotation in the internal combustion engine. <P>SOLUTION: The rotation angle detector of an internal combustion engine detects that the internal combustion engine has rotated by a specified angle on the basis of duty cycle of a pulse between pulse signals which equally divide a single rotation in the engine. In representing a rotational speed in the duty cycle Gn of a pulse including event timing in the present one cycle as the rotational speed in the immediately preceding duty cycle Gn-1 of a pulse, errors attendant on rotational-speed variation between respective pulse-intervals are corrected on the basis of a rotational-speed variation (Kt) in the same section in the preceding one cycle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an angle correction method for a rotation angle detecting device that detects an angle response time required for a rotating body of an internal combustion engine to advance by a specified angle from a predetermined position as a function of a rotation speed of the rotating body in the vicinity of the predetermined position. In particular, the present invention relates to an angle correction method for a rotation angle detection device that enables accurate angle detection regardless of a fluctuation in the rotation speed of an internal combustion engine.

  In the internal combustion engine, various event timings such as the ignition timing and the fuel injection timing are obtained from the rotation angle of the internal combustion engine. Therefore, the rotating body that rotates in synchronization with the internal combustion engine is provided with a plurality of pulsars or tooth-like projections at equal intervals along the circumferential direction, and this is detected by a magnetic pickup or an optical sensor. The pulse signal is output at equal angular intervals during one rotation of the rotating body.

However, it is difficult to obtain a sufficient angular resolution because of the restrictions on the number of pulsars and protrusions. Therefore, for example, in Patent Documents 1 and 2, when determining an event timing advanced by an angle θx after the J-th pulse signal is detected, an inter-pulse time Δt immediately before that is measured. If the rotation angle corresponding to the interval between pulses is, for example, 10 °, the angle response time Tx required to advance by the angle θx after the detection of the Jth pulse signal is the detection of the Jth pulse signal. Based on the timing, the following equation is used.

Tx = Δt × (θx / 10)

JP-A-5-137294 JP-A-6-213122

  As is well known, the rotational speed of the engine changes according to the stroke, and in the case of a 4-cycle engine, the rotational speed decreases from the second half of the compression stroke to the first half of the explosion stroke. This is even more pronounced with single-cylinder engines.

  However, in the above-described prior art, as shown in FIG. 5A, it is assumed that the current inter-pulse time Δta is the same as the previous inter-pulse time Δtb, and an event timing angle specified separately. Time Tx to reach θx is obtained. Therefore, if Δta> Δtb as shown in FIG. 5B or Δta <Δtb as shown in FIG. 5C with the engine speed fluctuation, There was a technical problem that a gap occurred.

  An object of the present invention is to solve the above-described problems of the prior art and to provide an angle correction method for a rotation angle detection device that can accurately determine an event timing given as a rotation angle of an internal combustion engine.

  In order to achieve the above-described object, the present invention represents the rotational speed in the inter-pulse section Gn including the event timing in one cycle of this time by the rotational speed in the immediately preceding inter-pulse section Gn-1. The present invention is characterized in that an error associated with the rotational speed fluctuation in each pulse interval is corrected based on the rotational speed fluctuation (Kt) in the same section in the previous cycle.

  According to the present invention, when converting the event timing given as the rotation angle of the internal combustion engine into the timing time on the time axis defined on the basis of the rotation speed of the internal combustion engine, the rotational speed of the internal combustion engine is detected. The deviation between the event timing angle that accompanies the fluctuation and the time to reach the event timing angle (angle response time) has been corrected, so the fuel injection timing and ignition timing that are based on the event timing are more It can be detected accurately, resulting in improved fuel economy and emission performance.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a rotation angle detection device for an internal combustion engine to which the present invention is applied, and includes an angle correction function that enables accurate angle detection regardless of the rotation speed fluctuation of the internal combustion engine. In the present embodiment, a case where the rotation angle of the four-cycle engine is detected as the rotation angle of the crankshaft will be described as an example.

  A disc-shaped rotating body 11 is integrally mounted on the crankshaft 10, and a plurality of protrusions 12 serving as detected portions are installed at equal intervals along the circumferential direction on the outer surface thereof. The protrusion 12 is detected by a proximity sensor 13 such as a magnetic pickup disposed opposite to the outer surface of the rotating body 11, an optical sensor that detects the reflected light from the protrusion 12 and the presence or absence of an optical path interruption by the protrusion 12. The The proximity sensor 13 detects the edge of the protrusion 12 as shown in FIG. 2, and the pulse signal generator 28 reverses every time the sensor output rises, that is, the front edge of the protrusion 12 is detected. A pulse signal P to be generated is generated. Therefore, the duty ratio of the pulse signal P is 50% in an ideal state where the engine speed does not vary.

  The reference clock generation unit 21 outputs a reference clock that is sufficiently faster than the pulse signal P. The inter-pulse time measuring unit 22 measures the inter-pulse time Δt of the pulse signal P using the reference clock.

  The inter-pulse time table 24 includes an inter-pulse time Δt [−72] 720 ° (one cycle) before the current inter-pulse time Δt, and an inter-pulse time Δt [710 ° before the inter-pulse time Δt [ -71]... Stores the inter-pulse time Δt [0] immediately before the current inter-pulse time Δt. The inter-pulse time update registration unit 23 updates and registers the measured inter-pulse time Δt in the inter-pulse time table 24. The timing correction coefficient (Kt) calculation unit 25, as will be described in detail later, is an inter-pulse time Δt [−72] 720 ° before the current inter-pulse time Δt and an inter-pulse time Δt [− [ 71] (Δt [−71] / Δt [−72]) is obtained and set as a timing correction coefficient (Kt).

  The angle response time (Tx) calculator 26 converts the event timing angle (θx) specified as the rotation angle of the crankshaft 10 into an angle response time (Tx) that is a function of time based on the pulse signal. The deviation between the event timing angle (θx) and the angle response time (Tx) caused by the engine speed fluctuation is corrected based on the timing correction coefficient (Kt). The event signal generation unit 27 generates an event timing signal indicating fuel injection timing, ignition timing, and the like based on the angle response time (Tx).

  FIG. 3 is a flowchart showing the operation of the present embodiment, and FIG. 4 is a timing chart thereof. In the present embodiment, a case where 36 protrusions are installed on the rotating body 11 of the crankshaft 10 at equal intervals will be described as an example. Therefore, in the present embodiment, the engine rotation angle corresponding to each pulse interval is 10 °.

  When the pulse signal P is input, the inter-pulse time measuring unit 22 measures the inter-pulse time Δt in step S1. In step S2, the inter-pulse time history stored in the inter-pulse time table 24 is shifted. For example, the inter-pulse time Δt [−71] before 710 ° is changed to the inter-pulse time Δt [−72] before 720 °. Is registered as an update. Similarly, the inter-pulse time Δt [−70] before 700 ° is updated and registered as the inter-pulse time Δt [−71] before 710 °. Similarly, the pulse time Δt [n] before n ° is updated and registered as the pulse time Δt [n−1] before (n−10) °.

In step S3, the inter-pulse time Δt measured in step S2 is updated and registered in the inter-pulse time table 24 as the previous inter-pulse time Δt [0]. In step S4, the timing correction coefficient Kt is obtained based on the following equation (2) in the Kt calculator 25.

Kt = Δt [-71] / Δt [-72] (1)

In step S6, it is determined whether or not the event timing angle θx is designated. If not specified, the process returns to step S1 and the above-described processes are repeated. When the event timing angle θx is designated, the process proceeds to step S6. In step S6, the angle response time Tx in which the timing shift depending on the periodic rotational speed fluctuation of the engine is corrected is obtained by the Tx calculation unit 26 based on the following equation (2).

Tx = (Δt [0] × θx × Kt) / 10 ° (2)

  That is, in this embodiment, the engine speed fluctuation depends on the stroke, and in the case of a single-cylinder four-cycle engine, attention is paid to regular fluctuations with two rotations of the crankshaft (720 °) as one cycle. And when representing the rotational speed in the inter-pulse section Gn including the event timing in the current cycle with the rotational speed in the immediately preceding inter-pulse section Gn-1, the rotational speed fluctuation in each inter-pulse section The error was corrected based on the rotational speed fluctuation (Kt) in the same section in the previous cycle.

Note that the time between the previous pulses is Δt, the fluctuation ratio (Kt) of the rotational speed in the same stroke of the previous cycle is (Δt2 / Δt1), and one rotation of the internal combustion engine is divided into M by the protrusion 12. For example, the above equation (2) can be generalized by the following equation (3).

Tx = Δt × {θx / (360 ° / M)} × (Δt2 / Δt1) (3)

  In step S7, the elapsed time from the start timing of the inter-pulse interval Gn is compared with the angle response time Tx. When the elapsed time reaches the angle response time Tx, the event signal generator 27 outputs a predetermined event in step S8. A timing signal is output.

  In the above-described embodiment, the deviation of the angle response time Tx is corrected based on the rotational speed fluctuation (Kt) in the same section before two revolutions (720 °) of the internal combustion engine. However, the internal combustion engine is a two-cycle engine. If there is, it is desirable to correct based on the rotational speed fluctuation in the same section before one rotation (360 °).

1 is a block diagram of a rotation angle detection device for an internal combustion engine according to the present invention. It is a wave form diagram of a pulse signal. It is the flowchart which showed the operation | movement of this embodiment. 3 is a timing chart showing the operation of the present embodiment. It is a wave form diagram for demonstrating the subject of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Crankshaft, 11 ... Rotating body, 12 ... Protrusion, 13 ... Proximity sensor, 21 ... Reference clock generation part, 22 ... Interpulse time measurement part, 23 ... Interpulse time update registration part, 24 ... Interpulse time table, 25... Timing correction coefficient (Kt) calculation unit 26. Angle response time (Tx) calculation unit 27 27 Event signal generation unit 28 28 Pulse signal generation unit

Claims (5)

In an angle correction method of a rotation angle detection device for detecting an angle response time required for a rotating body of an internal combustion engine to advance by a specified angle from a predetermined position as a function of a rotation speed of the rotating body in the vicinity of the predetermined position,
An angle correction method for a rotation angle detection device, comprising: detecting a rotation speed fluctuation in the vicinity of the predetermined position one rotation or more before the rotation body, and correcting the function based on the rotation speed fluctuation. M detected parts are provided at equal angular intervals on the rotating body of the internal combustion engine, and a pulse signal is output in response to each detected part,
a procedure for obtaining an inter-pulse time Δt1 in response to the (N−1) -th detected part before s rotation [variable s is a positive integer];
means for determining the time between pulses Δt2 in response to the Nth detected part before s rotation;
A procedure for obtaining an inter-pulse time Δt in response to the (N−1) -th detected part;
And a procedure for obtaining an angle response time Tx required for the rotating body to rotate by a specified angle θx from the start timing of the inter-pulse interval in response to the Nth detected portion, based on the following equation: An angle correction method for a rotation angle detection device.

Tx = Δt × {θx / (360 ° / M)} × (Δt2 / Δt1)
The angle correction method for a rotation angle detection device according to claim 2, wherein the internal combustion engine is a four-cycle engine, and the variable s is "2". The angle correction method for a rotation angle detection device according to claim 2, wherein the internal combustion engine is a two-cycle engine, and the variable s is "1". The angle correction method for a rotation angle detection device according to claim 1, wherein the rotating body is a crankshaft.

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