JP2001214791A - Cylinder discrimination device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylinder discrimination device for internal combustion engine capable of performing a cylinder discrimination in the early stage at the start of an engine without newly providing a part such as special sensor or the like. SOLUTION: The crankshaft 14 of the engine 11 repeats normal rotation and reverse rotating in the stopping process of the engine 1, and perfectly stops in a position slightly closer to lag side from the position where the reverse rotation is first generated. The reverse rotation of the crankshaft 14 is detected on the basis of the width Sigt of an ignition signal or the width Sne of the pulse signal from a crank position sensor 14c, which is parameter changing according to the rotating speed of the shaft 14. The reverse rotating is detected in this manner, whereby the stop position of the crankshaft can be predicted on the basis of this reverse rotation. On the basis of the predicted stop position of the crankshaft 14, the cylinder discrimination can be performed in the state where the engine 11 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder discriminating apparatus for an internal combustion engine.

[0002]

2. Description of the Related Art Generally, in an internal combustion engine such as an automobile engine having a plurality of cylinders, fuel injection and ignition are performed for each cylinder. Therefore, each cylinder is determined based on the rotational position of a crankshaft and a camshaft in the internal combustion engine. It is necessary to perform cylinder discrimination on the cylinders and to identify the cylinders for which fuel injection or ignition is to be performed. Therefore, conventionally, in order to know the rotational positions of the crankshaft and the camshaft, a signal rotor is attached to the crankshaft and the camshaft, and a crank position sensor and a cam position sensor are provided beside the signal rotor.

In a signal rotor of a crankshaft, a plurality of projections are formed at predetermined intervals in a circumferential direction of an outer peripheral surface thereof. Then, as each projection sequentially passes by the side of the crank position sensor as the crankshaft rotates, a pulse-like detection signal is output from the crank position sensor. In the signal rotor of the cam position sensor, a predetermined number (for example, one) of protrusions is formed on the outer peripheral surface. Then, as the projection passes along the side of the cam position sensor as the camshaft rotates, a detection signal is output from the cam position sensor at predetermined intervals in response to the passage of the projection.

The rotational positions of the crankshaft and the camshaft can be determined based on the detection signals from the crank position sensor and the cam position sensor.
Then, cylinder discrimination is performed based on the rotational positions of the crankshaft and the camshaft and the like, whereby the cylinder to be injected or ignited can be identified.

Incidentally, in order to know the rotational positions of the crankshaft and the camshaft based on the detection signals from the crank position sensor and the cam position sensor at the time of starting the engine, the shafts must be rotated to some extent. Therefore, when the crankshaft (camshaft) is forcibly rotated by a starter motor or the like at the time of starting the engine, the crankshaft and the camshaft must be rotated by an extra amount necessary to know the rotational position. Disappears. Then, by rotating the crankshaft and the camshaft to some extent, the rotational position of the shaft is known, and cylinders that perform fuel injection and ignition can be identified by performing cylinder discrimination based on these rotational positions and the like.

As described above, it is necessary to rotate the crankshaft and the camshaft to some extent in order to identify the cylinder in which the fuel injection or ignition is to be performed. This delays the start of the internal combustion engine. Therefore, for example, by adopting a cylinder discriminating device described in Japanese Patent Application Laid-Open No. 9-170483 and performing cylinder discrimination before starting the engine, it is possible to prevent the delay of the completion of the start of the internal combustion engine as described above. It is also possible to do.

The cylinder discriminating device described in the above publication is provided with a plurality of (four) camshaft rotating plates having different outer peripheral shapes attached to a camshaft, and provided on the side of each camshaft rotating plate, respectively. A sensor that outputs a signal corresponding to the outer peripheral shape. Since the outer peripheral shape of each camshaft rotary plate is different, the signal from each sensor is different according to the rotational position of the crankshaft and the camshaft. Therefore, the rotational positions of the crankshaft and the camshaft can be known based on the signals from the sensors.

In the cylinder discriminating apparatus, before the rotation of the crankshaft (camshaft) by the starter motor or the like is started, the positions (stop positions) of the crankshaft and the camshaft are known based on the signals from the sensors. be able to. Then, cylinder discrimination is performed based on the stop positions of the crankshaft and the camshaft and the like, and the cylinder that performs fuel injection and ignition can be identified. Therefore, immediately after the rotation of the crankshaft by the starter motor or the like is started, the fuel injection or ignition is performed in the cylinder, and the start of the internal combustion engine can be completed quickly.

[0009]

However, in the cylinder discriminating apparatus described in the above publication, a camshaft rotating plate and a sensor are newly added so that cylinder discrimination can be performed before the crankshaft is rotated by a starter motor or the like. Multiple (four each) must be provided. The labor and time required for mounting such components as the camshaft rotary plate and the sensor, and the cost increase due to such components, cannot be ignored.

The present invention has been made in view of such circumstances, and an object of the present invention is to make it possible to discriminate a cylinder at an early stage at the start of an engine without newly providing special parts such as sensors. An object of the present invention is to provide a cylinder discriminating device for an internal combustion engine.

[0011]

The means for achieving the above object and the effects thereof will be described below. In order to achieve the above object, the invention according to claim 1 is applied to a multi-cylinder internal combustion engine having a plurality of cylinders, and a cylinder discriminating device for an internal combustion engine that performs cylinder discrimination of each cylinder when the engine is stopped. Reverse rotation detection means for detecting reverse rotation of the internal combustion engine that occurs from the time the stop command is issued until the engine stops, and the cylinder discrimination based on the reverse rotation of the internal combustion engine detected by the reverse rotation detection means. Cylinder determining means for performing the determination.

According to the above arrangement, the reverse rotation detecting means detects the reverse rotation of the internal combustion engine. Based on the reverse rotation of the internal combustion engine, the rotational position of the crankshaft when the engine is stopped is predicted. Based on the predicted stop position of the crankshaft, it is possible to determine the cylinder of each cylinder while the engine is stopped. In some cases, the cylinder discrimination can be performed early. Also, since the reverse rotation of the internal combustion engine can be detected by a sensor or the like usually provided in the engine,
There is no need to provide a special sensor or the like for performing the above-described early cylinder determination at the time of engine start.

According to a second aspect of the present invention, in the first aspect of the invention, the cylinder discriminating means detects a reverse rotation of the internal combustion engine based on a rotation speed of the engine. When the internal combustion engine rotates in the reverse direction, the rotation speed of the engine decreases to the minimum value ("0"). Therefore, according to the above configuration in which the reverse rotation of the internal combustion engine is detected based on the rotation speed of the internal combustion engine, the reverse rotation of the internal combustion engine can be accurately detected.

According to a third aspect of the present invention, in the second aspect of the invention, there is further provided an ignition commanding means for outputting an ignition signal according to the rotation speed of the internal combustion engine, and the cylinder discriminating means is provided by the ignition commanding means. The reverse rotation of the internal combustion engine is detected based on the output ignition signal.

The width of the ignition signal output from the ignition command means changes according to the rotation speed of the internal combustion engine. Therefore, according to the above configuration, the reverse rotation of the internal combustion engine can be accurately detected based on the ignition signal output from the ignition command means.

According to a fourth aspect of the present invention, in the third aspect of the invention, the cylinder discriminating means detects the reverse rotation of the internal combustion engine based on the ignition signal width being equal to or greater than a predetermined value.

The width of the ignition signal increases as the rotational speed of the internal combustion engine decreases. Therefore, according to the above configuration in which the reverse rotation of the internal combustion engine is detected based on the width of the ignition signal being equal to or larger than the predetermined value, the reverse rotation of the internal combustion engine can be accurately detected.

According to a fifth aspect of the present invention, in the third aspect of the present invention, the cylinder discriminating means detects reverse rotation of the internal combustion engine based on a current ignition signal width and a previous ignition signal width. And

When the reverse rotation of the internal combustion engine occurs, the width of the current ignition signal differs greatly from the width of the previous ignition signal. Therefore, according to the above configuration in which the reverse rotation of the internal combustion engine is detected based on the width of the current ignition signal and the width of the previous ignition signal in the predetermined cylinder, the reverse rotation of the internal combustion engine can be accurately detected.

According to a sixth aspect of the present invention, in the second aspect of the invention, a crank position sensor for outputting a pulse-like signal corresponding to the rotation speed of the internal combustion engine is further provided,
The cylinder determining means detects reverse rotation of the internal combustion engine based on a pulse signal output from the crank position sensor.

The width of the pulse signal output from the crank position sensor changes according to the rotation speed of the internal combustion engine. Therefore, according to the above configuration, based on the signal output from the crank position sensor,
The reverse rotation of the internal combustion engine can be accurately detected.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the cylinder discriminating means detects the reverse rotation of the internal combustion engine based on the maximum width of a signal output from the crank position sensor. To do.

When the reverse rotation of the internal combustion engine occurs, the width of the pulse signal output from the crank position sensor becomes maximum. Therefore, according to the above configuration in which the reverse rotation of the internal combustion engine is detected based on the maximum width of the signal output from the crank position sensor, the reverse rotation of the internal combustion engine can be accurately detected.

According to an eighth aspect of the present invention, in the first aspect of the present invention, the fuel injection at the time of starting the engine is performed based on the cylinder discrimination of each cylinder in the engine stopped state by the cylinder discriminating means. The apparatus further includes an injection control unit for performing the operation.

According to the above configuration, appropriate fuel injection is performed for each cylinder immediately after the start of the engine, and the start of the internal combustion engine can be completed early. According to a ninth aspect of the present invention, in the invention of the eighth aspect, the injection control means determines a cylinder in an intake stroke when the engine is stopped, and executes fuel injection in the cylinder when an engine start command is issued. .

According to the above configuration, at the time of the engine start command, fuel injection is performed in the cylinder stopped during the intake stroke,
With this fuel injection, the start of the internal combustion engine can be completed early.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is applied to a four-cylinder gasoline engine for an automobile will be described below with reference to FIGS.

As shown in FIG. 2, a cylinder block 11a of an engine 11 having four cylinders # 1 to # 4 has a total of four pistons 12 for each of the cylinders # 1 to # 4. Are provided so as to be able to reciprocate. These pistons 12 are respectively connected to a crankshaft 14 which is an output shaft of the engine 11 via a connecting rod 13. The reciprocating movement of the piston 12 is converted into rotation of the crankshaft 14 by the connecting rod 13. In such an engine 11, a starter 51 used for starting the engine 11 is provided. The engine 11 is started by driving the starter 51 based on the operation of the ignition switch 52 to forcibly rotate the crankshaft 14.

As shown in FIG. 1, the crankshaft 14
Is provided with a signal rotor 14a. One missing tooth 14d is provided on the outer periphery of the signal rotor 14a.
Is provided, and a total of 34 protrusions 14b are provided at predetermined angles (10 ° in the present embodiment) about the axis of the crankshaft 14. A crank position sensor 14c is provided on the side of the signal rotor 14a. And crankshaft 1
4 rotates, and each projection 14b and missing tooth 14d of the signal rotor 14a sequentially pass by the side of the crank position sensor 14c, and the sensor 14c responds to the passage of each projection 14b and missing tooth 14d. A pulse-like detection signal is output.

In the engine 11, a cylinder head 15 is provided at an upper end of the cylinder block 11a. A combustion chamber 16 is provided between the cylinder head 15 and the piston 12, and an intake passage 32 and an exhaust passage 33 are connected to the combustion chamber 16. And the combustion chamber 16
The communication between the combustion chamber 16 and the exhaust passage 33 is controlled by the opening and closing operation of the exhaust valve 20.

On the other hand, an intake camshaft 21 and an exhaust camshaft 22 for opening and closing the intake valve 19 and the exhaust valve 20 are rotatably supported on the cylinder head 15. The intake and exhaust camshafts 21 and 22 are connected to the crankshaft 14 via a timing belt and gears (both not shown), and the rotation of the crankshaft 14 is transmitted by the belts and gears. .

In the cylinder head 15, a cam position sensor 21b for detecting a protrusion 21a provided on the outer peripheral surface of the intake camshaft 21 and outputting a detection signal is provided on a side of the intake camshaft 21. When the intake camshaft 21 rotates, the protrusion 21a of the shaft 21 passes by the side of the cam position sensor 21b. In this state, the cam position sensor 21b
Thus, the detection signal is output at predetermined intervals corresponding to the passage of the protrusion 21a.

In the intake passage 32, a fuel injection valve 40 for injecting fuel corresponding to the intake air amount of the engine 11 toward the intake passage 32 is provided at a downstream end thereof. Then, fuel is injected from the fuel injection valve 40 during the intake stroke, and a mixture of air and fuel is supplied into the combustion chamber 16 by the fuel injection. Further, an ignition plug 41 is provided in the cylinder head 15, and the ignition plug 41 ignites the air-fuel mixture in the combustion chamber 16 during the compression stroke. The ignition timing of the ignition plug 41 is determined by an igniter 41a provided above the plug 41.
Is controlled by When the air-fuel mixture in the combustion chamber is ignited and burned, the piston 12 reciprocates and the engine 11 is driven by the combustion energy at this time.

Next, the electrical configuration of the cylinder discriminating apparatus according to this embodiment will be described with reference to FIG. This cylinder discriminating apparatus includes an electronic control unit (hereinafter, referred to as an ECU) 92 for controlling the operating state of the engine 11 such as fuel injection control and ignition timing control. This ECU
An arithmetic logic circuit 92 includes a ROM 93, a CPU 94, a RAM 95, a backup RAM 96, and the like.

The ROM 93 is a memory that stores various control programs and maps that are referred to when the various control programs are executed.
The arithmetic processing is executed based on various control programs and maps stored in the OM 93. The RAM 95 is a CPU
94 is a memory for temporarily storing the calculation result at 94, data input from each sensor, and the like.
Reference numeral 6 denotes a non-volatile memory for storing data and the like stored when the engine 11 is stopped. And ROM9
3. CPU 94, RAM 95 and backup RAM 9
6 are connected to each other via a bus 97, and are also connected to an external input circuit 98 and an external output circuit 99.

The external input circuit 98 is connected to the crank position sensor 14c, the cam position sensor 21b, the starter 51, the ignition switch 52, and the like. The external output circuit 99 has the first cylinders # 1 to # 1.
Each fuel injection valve 40 and igniter 41a of the fourth cylinder # 4
Are connected respectively.

In the ECU 92 configured as described above, the power supply state is switched based on the operation of the ignition switch 52. Ignition switch 5
2 can be switched to four positions of an off position, an accessory position, an on position, and a start position,
ECU when in off position or accessory position
92 is in a non-energized state. When the ignition switch 52 is in the ON position, the ECU 92 is energized. When the ignition switch 52 is in the start position, the starter 51 is driven to forcibly rotate the crankshaft 14 (cranking).

Therefore, when starting the engine 11, the ignition switch 52 is switched to the start position, whereby the starter 51 forcibly rotates the crankshaft 14 to start the engine 11. After the start of the engine 11, the ignition switch 52 is located at the ON position.

During the operation of the engine 11, the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke correspond to the first cylinder # 1, the third cylinder # 3, the fourth cylinder as shown in FIG. The process is performed in the order of # 4 and second cylinder # 2. Then, in each of the cylinders # 1 to # 4, the fuel injection valve 40 is operated during the intake stroke.
And the ignition by the ignition plug 41 is performed during the compression stroke.

The ECU 92 receives signals from the crank position sensor 14c and the cam position sensor 21b, and detects the rotational positions of the crankshaft 14 and the intake camshaft 21 based on these signals. Here, signals from the crank position sensor 14c and the cam position sensor 21b input to the ECU 92 are shown in FIG.

FIG. 5B shows a signal output from the cam position sensor 21b as the crankshaft 14 (the intake camshaft 21) rotates. (C) shows a signal output from the crank position sensor 14c as the crankshaft 14 rotates. Of the signals output from the crank position sensor 14c shown in FIG. 5C, the number of pulse-like signals corresponding to the protrusions 14b is
It is “34” per rotation (360 ° CA).

In the signals output from the crank position sensor 14c, the number of pulse signals corresponding to the missing teeth 14d is determined by one rotation of the crankshaft 14 (360 °).
CA) is “1”. And the missing tooth 14
The pulse signal corresponding to d is output from the crank position sensor 14c during the compression stroke of the second cylinder # 2 and the third cylinder # 3, as shown in FIG. That is, the position of the missing tooth 14d is set such that a pulse signal corresponding to the missing tooth 14d is output at such a timing.

The ECU 92 includes the crank position sensor 14c and the cam position sensor 21b as described above.
, The rotational positions of the crankshaft 14 and the intake camshaft 21 are detected. And the ECU 9
2 is a crankshaft 14 and an intake camshaft 21
Cylinders are determined for each of the cylinders # 1 to # 4 based on the rotational position and the like, and the cylinders for which fuel injection and ignition are to be performed are identified among the cylinders # 1 to # 4.

When ignition is performed by the ignition plug 41 in each of the cylinders # 1 to # 4, the ECU 92 outputs an ignition signal to the igniter 41a of the cylinder to be ignited. By outputting such an ignition signal, the ECU 92 executes ignition by the ignition plug 41 in the cylinder. Here, the ignition signals output to the igniters 41a of the cylinders # 1 to # 4 are shown in FIG.

The ignition signals output to the igniters 41a of the cylinders # 1 to # 4 shown in FIG.
At 4, a fall occurs at the end of the compression stroke. The ignition by the ignition plug 41 is performed based on the fall of the ignition signal. Therefore, the timing of the ignition by the ignition plug 41 is controlled by adjusting the fall timing of the ignition signal.

When stopping the running engine 11, the ignition switch 52 is switched from the ON position to the accessory position or the OFF position. Then, when the ignition switch 52 is switched (a stop command is issued), the ECU 92 that is in the energized state is de-energized after a lapse of a predetermined time from this switching. The reason for delaying the de-energization of the ECU 92 is that a predetermined period of time is required to control the various devices to that state so that the various devices become optimal at the next engine start. That's why.

The various devices as described above include, for example, an idle speed control valve (ISCV) provided in the intake system of the engine 11. IS
The CV is preferably set to a predetermined opening when the engine is started, but is not necessarily set to the preferable opening when the engine is stopped when the engine is stopped. Therefore, between the time when the ignition switch 52 is switched to the off position or the accessory position and the time when the ECU 92 is turned off, the ECU 92 controls the ISCV to the above-described preferable opening.

When the ignition switch 52 is switched to the off position or the accessory position, the EC
U92 stops the fuel injection from the fuel injection valve 40 and stops the operation of the engine 11. In such an engine stop process, the timing of the ignition signal output from the ECU 92 is fixed at a predetermined crank angle before the top dead center (TDC), and the timing of the fall is determined at the top dead center. Fixed to Therefore, the width of the ignition signal in this state becomes larger as the rotation of the crankshaft 14 becomes slower and the interval between the rising timing and the falling timing of the ignition signal becomes longer.

When the fuel injection from the fuel injection valve 40 is stopped to stop the engine 11, the rotation speed of the crankshaft 14 (the rotation speed of the engine 11) is reduced.
Gradually decreases. In this state, the resistance when the volume of the combustion chamber 16 closed by the cylinder in the compression stroke is reduced and the resistance when the volume of the combustion chamber 16 closed by the cylinder in the expansion stroke are expanded are reduced. It is against the rotation of the crankshaft 14.

In the cylinder during the compression stroke, the combustion chamber 16
Air in the combustion chamber 16 acts like a tension spring in the cylinder during the expansion stroke. Therefore, in the engine 11 in the stop process, after the rotation speed of the crankshaft 14 reaches the minimum value (“0”), the air in the combustion chamber 16 causes the crankshaft 14 to start rotating in the reverse direction. . Further, when the rotation speed becomes "0" during the reverse rotation of the crankshaft 14, the air in the combustion chamber 16 also causes the crankshaft 14 to rotate forward again.

In this way, the crankshaft 14 repeats the forward rotation and the reverse rotation, but the forward rotation and the reverse rotation do not both have a large rotation angle, and after all, the compression stroke occurs when the first reverse rotation occurs. The rotation of the crankshaft 14 is completely stopped while the cylinder which has been operated remains in the compression stroke. The stop position of the crankshaft 14 is a position on the retard side by a predetermined angle from the crank angle at the time when the reverse rotation occurs for the first time. Therefore, by detecting the reverse rotation as described above, the stop position of the crankshaft 14 (the rotational position of the crankshaft 14 when the engine is stopped) can be predicted.

In the present embodiment, an ignition signal, which is a parameter that changes in accordance with a decrease in the rotation speed of the crankshaft 14, during a period from when the ignition switch 52 is switched to the off position or the accessory position to when the ECU 92 is de-energized. Based on crankshaft 14
Reverse rotation is detected. That is, in the ignition signal as shown in FIG.
Since the rotation speed gradually increases as the rotation speed of the crankshaft 14 decreases, it is possible to determine whether or not the crankshaft 14 has reversely rotated based on whether or not the same width Sigt is larger than the predetermined value X3. The predetermined value X3 is set to a value corresponding to the rotation speed (ignition signal width Sigt) of the crankshaft 14 immediately before such reverse rotation occurs.

The width Sigt of the ignition signal is set to a predetermined value X3.
When the reverse rotation of the crankshaft 14 is detected based on the rotation speed of the crankshaft 14 based on the rotational position of the crankshaft 14 when the reverse rotation occurs,
4 can be predicted. Further, since it is possible to determine the cylinders of the cylinders # 1 to # 4 in a state where the engine 11 is stopped based on the predicted stop position of the crankshaft 14, the cylinder determination is performed early when the engine is started. Will be able to do it. Further, it is not necessary to provide a special sensor or the like for realizing such an early cylinder discrimination at the time of starting the engine, and the cost does not increase due to the sensor or the like.

Next, based on the reverse rotation of the engine 11 (reverse rotation of the crankshaft 14), the crankshaft 14
Will be described with reference to the flowchart of FIG. 6 showing a stop position prediction routine.
This stop position prediction routine is performed when the ignition switch 52 is switched to the off position or the accessory position during the operation of the engine 11 and the engine speed NE becomes less than a predetermined value X1 (for example, idle speed).
This is executed through the ECU 92. The engine speed NE is determined based on a detection signal from the crank position sensor 14c.

In the stop position prediction routine, the ECU 9
2 measures the width Sne of the signal output from the crank position sensor 14c as shown in FIG. Subsequently, step S102
Of the cylinders # 1 to # 4 during the compression stroke is identified, and it is determined in the process of step S103 whether or not the piston 12 of the cylinder is located at the top dead center (TDC). The processing after step S103 is for predicting the stop position of the crankshaft 14.

In the process of step S103, if the determination is affirmative (YES), steps S104-S
The processing of step S106 is executed, and if negative determination (NO), the processing of steps S107 and S108 is executed. If the crankshaft 14 is stopped in a state where the cylinders 1 to # 4 are in the compression stroke, the rotation of the crankshaft 14 is repeated in the process of stopping the engine 11, and the rotation of the shaft 14 is stopped. Position is step S104-S
It is predicted by the processing of 106.

The ECU 92 measures the ignition signal width Sigt corresponding to the cylinder in the compression stroke in the processing of step S104, and determines in step S105 whether the ignition signal width Sigt is larger than the predetermined value X3 described above. Judge. The process in step S105 is for detecting reverse rotation of the crankshaft 14 (reverse rotation of the engine 11). That is, the width Sigt of the ignition signal gradually increases as shown in FIG. 7 when the rotation speed of the crankshaft 14 decreases. Therefore, based on the fact that the width Sigt of the ignition signal is larger than the predetermined value X3, it is possible to determine that the reverse rotation has occurred.

If it is determined in step S105 that "Sigt>X3" is not satisfied and that the reverse rotation of the crankshaft 14 has not occurred, step S101 is performed.
Return to Further, in the process of step S105, “S
If igt> X3 ", it is determined that reverse rotation of the crankshaft 14 has occurred before the piston 12 reaches the top dead center in the cylinder during the compression stroke, and the process proceeds to step S106.

When the process proceeds to step S106, E
The CU 92 predicts that the crankshaft 14 will stop at a rotational position where the piston 12 of the cylinder stops during the compression stroke. Note that, as described above, the crankshaft 14
May occur when each of the cylinders # 1 to # 4 is in the compression stroke. Therefore, the following four patterns (A) to (D) are given as patterns of the stop position of the crankshaft 14 as described above.

(A) The crankshaft 14 is stopped at the rotational position where the cylinder # 1 is in the compression stroke. (B) The crankshaft 14 is stopped at a rotational position where the second cylinder # 2 is in the compression stroke.

(C) The crankshaft 14 is stopped at a rotational position where the third cylinder # 3 is in the compression stroke. (D) The crankshaft 14 stops at a rotational position where the fourth cylinder # 4 is in the compression stroke.

In the process of step S106, the ECU 92 sets the stop prediction flag F2 (n) according to the predicted stop position of the crankshaft 14. The four stop prediction flags F2 (n) (n = 1, 2, 3, 4) are prepared corresponding to the four stop position patterns of the crankshaft 14 shown in (A) to (D). I have. Then, among the four stop prediction flags F2 (n), the one corresponding to the predicted stop position of the crankshaft 14 is set to "1" in the process of step S106. Here, the setting mode of the four stop prediction flags F2 (n) will be described below.

In the pattern (A), "1" is stored in a predetermined area of the backup RAM 96 as the stop prediction flag F2 (1). In the pattern (B), “1” is stored in a predetermined area of the backup RAM 96 as the stop prediction flag F2 (2).

In the pattern (C), “1” is stored in a predetermined area of the backup RAM 96 as the stop prediction flag F2 (3). In the pattern (D), “1” is stored in a predetermined area of the backup RAM 96 as the stop prediction flag F2 (4).

After the stop prediction flag F2 (n) is set as described above by the processing of step S106, the EC
U92 ends the stop position prediction routine. By the way, during the stop process of the engine 11, the repetition of the normal rotation and the reverse rotation of the crankshaft 14 described above usually occurs. However, when the rotation speed of the crankshaft 14 becomes the minimum value (“0”) for the first time, the pistons 12 of the cylinders # 1 to # 4 rarely move to the top dead center (TDC).
And at the bottom dead center (BDC). In this case, the crankshaft 14 stops at a rotational position such that the piston 12 is located at the top dead center and the bottom dead center without reverse rotation. The stop position of the crankshaft 14 in such a case is predicted by the processing of steps S107 and S108.

When it is determined in step S103 that the piston 12 of the cylinder in the compression stroke is located at the top dead center (TDC), the ECU 92 determines in step S107 that the crank position sensor 1
It is determined whether or not the width Sne of the signal from 4c is larger than a predetermined value X2. When the crankshaft 14 is stopped, the signal width Sne is larger than the predetermined value X2. Therefore, whether the crankshaft 14 is stopped is determined based on whether or not “Sne> X2”. Is determined. The predetermined value X2 is set to a value that can accurately determine such stop of the crankshaft 14.

If it is determined in step S107 that "Sne>X2" is not satisfied and the crankshaft 14 is not stopped, the process returns to step S101. If “Sne> X2” and the crankshaft 1
If it is determined that Step 4 is stopped, the process proceeds to Step S108.

When the process proceeds to step S108,
The CU 92 calculates the top dead center (TD) after the compression stroke in the cylinder.
It is predicted that the crankshaft 14 is stopped at a rotational position where the piston 12 stops at C). The stoppage of the crankshaft 14 can occur when the pistons 12 of the cylinders # 1 to # 4 are located at the top dead center after the compression stroke. Therefore, the following four patterns (E) to (H) are given as patterns of the stop position of the crankshaft 14 as described above.

(E) The crankshaft 14 is stopped at a rotational position such that the piston position of the first cylinder # 1 becomes the top dead center after the compression stroke. (F) The crankshaft 14 stops at a rotational position where the piston position of the second cylinder # 2 becomes the top dead center after the compression stroke.

(G) The crankshaft 14 stops at a rotational position such that the piston position of the third cylinder # 3 becomes the top dead center after the compression stroke. (H) The crankshaft 14 stops at a rotational position where the piston position of the fourth cylinder # 4 becomes the top dead center after the compression stroke.

In the process of step S108, the ECU 92 sets the TDC stop prediction flag F1 (n) according to the predicted stop position of the crankshaft 14. This TDC stop prediction flag F1 (n) (n = 1, 2, 2,
Four types (3, 4) are prepared corresponding to the patterns of the stop positions of the crankshaft 14 shown in the above (E) to (H). Then, these four TDC stop prediction flags F1
Of (n), the one corresponding to the predicted stop position of the crankshaft 14 is set to “1” in the processing of step 108. Here, the setting mode of the four TDC stop prediction flags F1 (n) will be described below.

In the pattern (E), “1” is set as the TDC stop prediction flag F 1 (1) in the backup RAM 9.
6 in a predetermined area. In the pattern (F), the TDC stop prediction flag F1
(2) “1” is stored in a predetermined area of the backup RAM 96 as (2).

In the pattern (G), “1” is set to the backup RAM 9 as the TDC stop prediction flag F1 (3).
6 in a predetermined area. In the pattern (H), the TDC stop prediction flag F1
(4) "1" is stored in a predetermined area of the backup RAM 96.

After the TDC stop prediction flag F1 (n) is set as described above by the processing in step S108, the ECU 92 ends the stop position prediction routine. Next, the procedure of cylinder discrimination, fuel injection control, and ignition timing control of each of the cylinders # 1 to # 4 at the time of engine start will be described with reference to FIGS. 8 to 11 are flowcharts showing a start-time control routine for performing cylinder discrimination, fuel injection control, and ignition timing control when the engine 11 starts. The start-time control routine is executed through the ECU 92 when the ignition switch 52 is switched from the off position or the accessory position to the on position (when an engine start command is issued).

In the starting control routine, the ECU 92
Is the stop prediction flag F2 (n) stored in the backup RAM 96 as the process of step S201 (FIG. 8),
And the TDC stop prediction flag F1 (n), the stop position of the crankshaft 14 is predicted, and each cylinder #
The cylinder identification of # 1 to # 4 is performed. Each of the flags corresponds to the stop position of the crankshaft 14, and the stop position of the crankshaft 14 is predicted as follows based on which of the flags is set to "1".

If "F1 (1) = 1", it is predicted that the crankshaft 14 is stopped at a rotational position where the piston 12 of the first cylinder # 1 is located at the top dead center.・ If “F1 (2) = 1”, the piston 12 of the second cylinder # 2
It is predicted that the crankshaft 14 is stopped at a rotational position where is located at the top dead center.

If "F1 (3) = 1", it is predicted that the crankshaft 14 is stopped at a rotational position where the piston 12 of the third cylinder # 3 is located at the top dead center.・ If “F1 (4) = 1”, the piston 12 of the fourth cylinder # 1
It is predicted that the crankshaft 14 is stopped at a rotational position where is located at the top dead center.

If "F2 (1) = 1", it is predicted that the crankshaft 14 is stopped at the rotational position where the cylinder # 1 is in the compression stroke. If “F2 (2) = 1”, it is predicted that the crankshaft 14 is stopped at the rotational position where the second cylinder # 2 is in the compression stroke.

If “F2 (3) = 1”, it is predicted that the crankshaft 14 is stopped at the rotational position where the third cylinder # 3 is in the compression stroke. If “F2 (4) = 1”, it is predicted that the crankshaft 14 is stopped at the rotational position where the fourth cylinder # 4 is in the compression stroke.

Since the cylinder discrimination of each of the cylinders # 1 to # 4 can be performed based on the predicted stop position of the crankshaft 14, the cylinder discrimination can be performed early at the time of starting the engine. After performing the cylinder determination, the process proceeds to step S202.

The ECU 92 performs the process in step S201 based on the signal from the starter 51.
It is determined whether or not is operating. And starter 5
If it is determined that No. 1 is not operating, step S20
The process of step 2 is repeatedly performed, and if it is determined that the starter 51 is operating, the process proceeds to step S203. ECU 92
Is the stop prediction flag F2 in the process of step S203.
(n) and “0” as the TDC stop prediction flag F1 (n).
Is stored in a predetermined area of the backup RAM 96, and each flag is reset.

The ECU 92 starts counting the number of pulse signals output from the crank position sensor 14c as the process of step S204. The counting of the pulse signal is executed by another routine, and the counted number obtained by this is used in the later-described processing of the starting control routine.

The ECU 92 determines whether the pistons 12 of the cylinders # 1 to # 4 are started from a state where the pistons 12 are located at the top dead center and the bottom dead center, as the processing of the subsequent step S205. In the case of starting from a state where the piston 12 is located at the top dead center and the bottom dead center, the accurate rotational position of the crankshaft 14 can be grasped before the starter 51 operates. Therefore, the timing at which fuel injection and ignition should be performed immediately after the operation of the starter 51 is determined by the crank position sensor 14.
This allows accurate recognition based on c and the detection signal from the cam position sensor 21b.

Therefore, in the process of step S205, Y
If ES is determined, the process proceeds to step S206 and immediately shifts to operation based on normal fuel injection control and ignition timing control as shown in FIG. In such a normal operation, the fuel injection valve 4 is operated in the intake stroke of each of the cylinders # 1 to # 4.
0, fuel injection from each cylinder # 1 to #
In the compression stroke of No. 4, ignition by the spark plug 41 is performed.
After executing the processing of step S206, the ECU 92
Ends the start-time control routine.

On the other hand, if NO in step S205
If it is determined that the process has been performed, the process proceeds to step S207 (FIG. 9). The ECU 92 determines whether or not the cylinder # 1 is started from the state in which the cylinder # 1 is in the compression stroke as the process of step S207. If YES, step S20
Proceed to 8. When starting from such a state, the exact rotational position of the crankshaft 14 at the start of starting cannot be grasped.
Since the fuel injection control during the normal operation as described above cannot be executed, the fuel injection control based on the processing of steps S208 to S210 is executed instead.

FIG. 12 shows how various signals are output and how fuel injection is performed when cylinder # 1 is started from the state where it is in the compression stroke.
A description will be given based on the time chart of FIG.

In FIG. 12, (a), (b),
(C) and (d) show the output modes of the ignition signal to the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2, respectively, and the fuel injection modes in these cylinders. Is shown. (E) shows the operation mode of the starter 51, and (f) and (g) show the cam position sensor 21b and the crank position sensor 1 respectively.
4C shows an output mode of a signal from the terminal 4c.

When the starter 51 operates as shown in FIG. 12E, the crankshaft 14 (the intake camshaft 21) is forcibly rotated. As a result, a signal as shown by a solid line in FIG. 12 (f) is output from the cam position sensor 21b, and a signal as shown by a solid line in FIG. 12 (g) is output from the crank position sensor 14c. When the first cylinder # 1 is in the compression stroke, the third cylinder # 3 is in the intake stroke as shown by the dashed line L1 in FIG. Therefore, when starting the engine from the state where the first cylinder # 1 is in the compression stroke, the ECU 92 sets the starter 5
Simultaneously with the operation of No. 1, fuel injection in the third cylinder # 3 is executed as shown by the solid line in FIG.

The ECU 92 starts counting the number of pulse signals from the crankshaft 14 when the starter 51 starts operating. And, this count number is the number of each cylinder # 1
The value determined that # 4 has shifted to the next step, for example, “9
(Corresponding to 90 ° CA) ”or more.
Executes the fuel injection in the fourth cylinder # 4 as shown by the solid line in FIG. This is because each cylinder # 1
This is because when # 4 shifts to the next stroke, as shown in FIG. 4, the fourth cylinder # 4 enters the intake stroke.

During the intake stroke of the fourth cylinder # 4, the missing tooth 14d passes by the side of the crank position sensor 14c. Based on the fact that the width Sne of the predetermined pulse signal from the crank position sensor 14c shown in FIG. 12 (g) is larger than the signals before and after the signal, the ECU 92 determines that the pulse signal corresponds to the missing tooth 14d. It is determined that it is. After the missing tooth determination is performed, the rotational position of the crankshaft 14 can be accurately grasped, so that the normal operation is performed through the ECU 92. That is, based on signals from the crankshaft 14 and the cam position sensor 21b, fuel is injected from the fuel injection valve 40 in the intake stroke of each of the cylinders # 1 to # 4, and ignition is performed by the ignition plug 41 in the compression stroke. .

The above-described control after the start of the engine start is executed by the processing after step S208 (FIG. 9) of the start-time control routine. That is, when the ECU 92 determines that the cylinder # 1 is started from the state in which the cylinder # 1 is in the compression stroke based on the cylinder determination processing in step S201 (FIG. 8) performed before the operation of the starter 51, step S208.
The fuel injection is executed in the third cylinder # 3 at the same time as the start of the operation of the starter 51.

The ECU 92 determines whether or not the count number of the pulse signal of the crank position sensor 14c is equal to or more than a predetermined value X4 ("9" in the present embodiment) as the process of the subsequent step S209. And NO
If so, the determination processing of step S209 is repeatedly executed,
If YES, the process proceeds to step S210. The ECU 92
As the process of step S210, fuel injection is performed in the fourth cylinder # 4.

Subsequently, the ECU 92 performs the above-described missing tooth determination as the process of step S211. If the pulse signal from the crank position sensor 14c does not correspond to the missing tooth 14d, the process proceeds to step S21.
1 is repeatedly executed. When it is determined that the pulse signal corresponds to the missing tooth 14d, the process proceeds to step S212, shifts to the normal operation, and ends the start-time control routine.

On the other hand, if it is determined in step S207 that the cylinder # 1 is not started from the state in which the cylinder # 1 is in the compression stroke, the process proceeds to step 213. ECU 92
Determines as the process in step S213 whether or not the fourth cylinder # 4 is started from a state in which the fourth cylinder is in the compression stroke.
If YES, the process proceeds to step S214. Even in the start from such a state, the accurate rotational position of the crankshaft 14 at the start of the start cannot be ascertained as described above, and the fuel injection control during the normal operation cannot be executed. Execute control.

Here, when the fourth cylinder # 4 is started from the state where it is in the compression stroke, how various signals are output and how fuel injection is performed are shown in FIG. Explanation will be made based on the chart.

When the starter 51 operates as shown in FIG. 12 (e), the two-dot chain line in FIG. 12 (f) is obtained from the cam position sensor 21b and the crank position sensor 14c.
And a signal as shown by a solid line in FIG. When the fourth cylinder # 4 is in the compression stroke, the second cylinder # 2 is in the intake stroke as shown by the one-dot chain line L2 in FIG. Therefore, when starting from the state where the fourth cylinder # 4 is in the compression stroke, the ECU 92 simultaneously operates the starter 51 and performs the fuel injection in the second cylinder # 2 as shown by the two-dot chain line in FIG. Execute

The ECU 92 starts counting the number of pulse signals from the crankshaft 14 when the starter 51 starts operating. And, this count number is the number of each cylinder # 1
When the value of # 4 becomes equal to or more than the value determined to shift to the next step (in this embodiment, “9 (corresponding to 90 ° CA)”),
The CU 92 executes the fuel injection in the first cylinder # 1 as shown by a two-dot chain line in FIG. This is because, as described above, when each of the cylinders # 1 to # 4 shifts to the next stroke, the first cylinder # 1 enters the intake stroke, as can be seen from FIG.

During the intake stroke of the first cylinder # 1, the missing tooth 14d passes by the side of the crank position sensor 14c. Based on the fact that the width Sne of the predetermined pulse signal from the crank position sensor 14c shown in FIG. 12 (g) is larger than the signals before and after the signal, the ECU 92 determines that the pulse signal corresponds to the missing tooth 14d. It is determined that it is. After the missing tooth determination is performed, the rotational position of the crankshaft 14 can be accurately grasped, so that the normal operation is performed through the ECU 92.

The above-described control after the start of the engine start is executed by the processing after step S214 (FIG. 9) of the start-time control routine. That is, when the ECU 92 determines that the fourth cylinder # 4 is started from the state where the fourth cylinder # 4 is in the compression stroke, based on the cylinder determination processing in step S201 (FIG. 8) performed before the operation of the starter 51, step S214 is performed.
The fuel injection is executed in the second cylinder # 2 at the same time as the start of the operation of the starter 51.

The ECU 92 determines whether or not the count number of the pulse signal of the crank position sensor 14c has reached a predetermined value X4 ("9" in the present embodiment) or more as the process of the subsequent step S215. And NO
If so, the determination processing of step S215 is repeatedly executed,
If YES, the process proceeds to step S216. The ECU 92
As the process of step S216, fuel injection is executed in the first cylinder # 1. After that, the ECU 92 sequentially executes the processing of steps S211 and S212, and thereafter ends the start-time control routine.

On the other hand, if it is determined in step S214 that the fourth cylinder # 4 is not started from a state in which the fourth cylinder is in the compression stroke, the process proceeds to step S217 (FIG. 10). The ECU 92 determines whether or not the third cylinder # 3 is started from a state in which the third cylinder # 3 is in the compression stroke, as the process of step S217. If YES, step S21
Proceed to 8. Even in the start from such a state, the accurate rotation position of the crankshaft 14 at the start of the start cannot be ascertained as described above, and the fuel injection control and the ignition timing control during the normal operation cannot be executed. Fuel injection control and ignition timing control based on the

Here, when the third cylinder # 3 is started from the state where it is in the compression stroke, how various signals are output and how fuel injection is performed are shown in the time chart of FIG. Explanation will be made based on the chart.

In FIG. 13, (a), (b),
(C) and (d) show the output modes of the ignition signal to the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2, respectively, and the fuel injection modes in these cylinders. Is shown. (E) shows the operation mode of the starter 51, and (f) and (g) show the cam position sensor 21b and the crank position sensor 1 respectively.
4C shows an output mode of a signal from the terminal 4c.

When the starter 51 operates as shown in FIG. 13 (e), signals as shown by the solid line in FIG. 13 (f) and the solid line in FIG. 13 (g) are output from the cam position sensor 21b and the crank position sensor 14c. Is output. When the third cylinder # 3 is in the compression stroke, the fourth cylinder # 4 is in the intake stroke as shown by the one-dot chain line L3 in FIG. Therefore, when starting from a state where the third cylinder # 3 is in the compression stroke, the ECU 92 executes the fuel injection in the fourth cylinder # 4 as shown by the solid line in FIG. I do.

In starting from the state where the third cylinder # 3 is in the compression stroke, the missing tooth 14d passes by the side of the crank position sensor 14c immediately after the start according to the stop position of the crankshaft 14 before the start. There is a case where the above-described missing tooth determination is performed and a case where the same missing tooth determination is not performed because the same missing tooth 14d does not pass. Also, even if the missing tooth 14d actually passes by the side of the crank position sensor 14c,
Immediately after the start, the tooth missing determination may not be performed because the rotation of the crankshaft 14 is not stable.

Immediately after the start, the third cylinder # 3 is in the middle of the compression stroke, and if the above-described missing tooth determination is made, the rotational position of the crankshaft 14 can be accurately grasped. Performs an operation (normal operation) based on normal fuel injection control and ignition timing control.

Further, for some reason, the above-described missing tooth determination may not be performed. In this case, the count number of the pulse signal of the crank position sensor 14c is
When the value of each of the cylinders # 1 to # 4 is determined to have shifted to the next stroke (in this embodiment, “9 (corresponding to 90 ° CA)”) or more, the ECU 92 sets the solid line in FIG. The fuel injection in the second cylinder # 2 is executed as shown by the following: When the cylinders # 1 to # 4 shift to the next stroke as described above,
This is because the second cylinder # 2 performs the intake stroke as can be seen from FIG.

When the count number of the pulse signal is equal to or greater than the value ("18 (corresponding to 180 ° CA)" in this embodiment) where the piston position of the fourth cylinder # 4 is near the top dead center after the compression stroke. The ECU 92 executes ignition in the fourth cylinder # 4 as shown by a solid line in FIG. Further, the ECU 9
2 is the first cylinder # 1 which is the cylinder to be injected next.
In FIG. 13, fuel injection is executed as shown by the solid line in FIG.

After such ignition and fuel injection, the missing tooth 14d passes by the crank position sensor 14c based on the rotation of the crankshaft 14 of 360 ° CA or more from the start of starting. In this case, the above-described missing tooth determination is performed, and after the determination, the ECU 92
Performs normal fuel injection control and ignition timing control (normal operation) based on signals from the crank position sensor 14c and the cam position sensor 21b.

The control after the start of the engine as described above is executed by the processing after step S218 of the start control routine. That is, when the ECU 92 determines that the start is from the state where the third cylinder # 3 is in the compression stroke, based on the cylinder discriminating process of step S201 (FIG. 8) performed before the operation of the starter 51, the process proceeds to step S218. As a process, fuel injection is executed in the fourth cylinder # 4 at the same time as the starter 51 starts operating.

The ECU 92 determines whether or not the missing tooth has been determined based on the pulse signal of the crank position sensor 14c as the process of step S219. If the missing tooth has been determined, it means that the rotational position of the crankshaft 14 can be accurately grasped, so that the process proceeds to step S226 and shifts to the normal operation. In the process of step S219, if it is determined that the missing tooth determination is not performed for any reason,
Proceed to step S220.

The ECU 92 determines whether the count of the pulse signal of the crankshaft 14 has exceeded a predetermined value X5 ("9" in the present embodiment) or not, as the process of step S220. If NO, step S21
9, if YES, the fuel injection is executed in the second cylinder # 2 as the process of step S221. Next, EC
U92 determines that the count number of the pulse signal is a predetermined value Y (in this embodiment, "1" in the process of step S222).
8 ") It is determined whether or not the above has been reached. If NO, the process of step S222 is repeatedly executed, and YE
If S, the processes of steps S223 and S224 are sequentially executed.

The ECU 92 executes ignition in the fourth cylinder # 4 as the processing in step S223, and executes processing in step S224.
Is executed in the first cylinder # 1. After that, the ECU 92 performs the process of step S225 as follows:
It is determined whether or not the missing tooth determination has been made in the same manner as the processing in step S219. If the missing tooth determination has not been made, the process of step S225 is repeatedly executed. If the missing tooth determination has been made, the process of step S226 is executed, and then the start-time control routine ends.

On the other hand, in the process of step S217, when it is determined that the third cylinder # 3 is not started from the state where it is in the compression stroke, that is, the second cylinder # 2 is started from the state where it is in the compression stroke. If so, step S2
Proceed to 27 (FIG. 11). Even when starting from such a state,
As described above, since the accurate rotational position of the crankshaft 14 at the start of the start cannot be grasped, and the fuel injection control and the ignition timing control at the time of the normal operation cannot be executed, step S227 is performed.
To S233, the fuel injection control and the ignition timing control are executed.

Here, when the second cylinder # 2 is started from the state where it is in the compression stroke, how various signals are output and how fuel injection is performed are shown in the time chart of FIG. Explanation will be made based on the chart.

When the starter 51 operates as shown in FIG. 13 (e), the two-dot chain line in FIG. 13 (f) is obtained from the cam position sensor 21b and the crank position sensor 14c.
And a signal as shown by the solid line in FIG. When the second cylinder # 2 is in the compression stroke, the first cylinder # 1 is in the intake stroke as shown by the dashed line L4 in FIG. Therefore, when starting from a state in which the second cylinder # 2 is in the compression stroke, the ECU 92 simultaneously operates the starter 51 with the fuel injection in the first cylinder # 1 as shown by a two-dot chain line in FIG. Execute

Even when starting from the state where the second cylinder # 2 is in the compression stroke, depending on the stop position of the crankshaft 14 before the start, the above-described missing tooth determination is performed immediately after the start, and the same missing tooth determination is performed. May not be done.

Immediately after the start, when the second cylinder # 2 is in the middle of the compression stroke, if the above-described missing tooth determination is made, the rotational position of the crankshaft 14 can be accurately grasped. Performs an operation (normal operation) based on normal fuel injection control and ignition timing control.

If the above-described missing tooth determination is not performed for some reason, the crank position sensor 1
The count number of the pulse signal of 4c is a value that determines that each cylinder # 1 to # 4 has shifted to the next stroke (in the present embodiment,
EC when "9 (corresponding to 90 ° CA)") or more
U92 executes the fuel injection in the third cylinder # 3 as shown by the two-dot chain line in FIG. This is because, as described above, when the cylinders # 1 to # 4 shift to the next stroke, the third cylinder # 3 enters the intake stroke as can be seen from FIG.

When the count number of the pulse signal becomes equal to or greater than the value (18 (corresponding to 180 ° CA) in this embodiment) at which the piston position of the first cylinder # 1 is near the top dead center after the compression stroke. The ECU 92 performs ignition in the first cylinder # 1, as indicated by a two-dot chain line in FIG. Furthermore, EC
The U92 executes the fuel injection in the fourth cylinder # 4, which is the cylinder for which the fuel injection is to be performed next, as shown by the two-dot chain line in FIG.

After such ignition or fuel injection, the missing tooth 14d passes by the crank position sensor 14c based on the rotation of the crankshaft 14 of 360 ° CA or more from the start of starting. In this case, the above-described missing tooth determination is performed, and after the determination, the ECU 92
Performs normal fuel injection control and ignition timing control (normal operation) based on signals from the crank position sensor 14c and the cam position sensor 21b.

The above-described control after the engine is started is executed by the processing after step S227 of the start-time control routine. That is, when the ECU 92 determines that the start is from the state where the second cylinder # 2 is in the compression stroke, based on the cylinder determination processing in step S201 (FIG. 8) performed before the operation of the starter 51, the ECU 92 proceeds to step S227. As a process, fuel injection is executed in the first cylinder # 1 simultaneously with the start of operation of the starter 51.

The ECU 92 determines whether or not the missing tooth has been determined based on the pulse signal of the crank position sensor 14c as the process of the subsequent step S228. If the missing tooth has been determined, it means that the accurate rotational position of the crankshaft 14 can be grasped, and the process proceeds to step S235 and shifts to the normal operation. In the process of step S228, if it is determined that the missing tooth determination is not performed for any reason,
Proceed to step S229.

The ECU 92 determines whether or not the count number of the pulse signal of the crankshaft 14 has exceeded a predetermined value X5 ("9" in the present embodiment) as the process of step S229. If NO, step S22
8, if YES, the fuel injection is executed in the third cylinder # 3 as the process of step S230. Next, EC
U92 determines that the count number of the pulse signal is a predetermined value Y (“1” in the present embodiment) as the process of step S231.
8 ") It is determined whether or not the above has been reached. If NO, the process of step S231 is repeatedly executed, and YE
If S, the processes of steps S232 and S233 are sequentially executed.

The ECU 92 executes the ignition in the first cylinder # 1 as the processing in step S232, and executes the processing in step S233.
The fuel injection is executed in the fourth cylinder # 4. After that, the ECU 92 performs the process of step S234 as follows:
It is determined whether the missing tooth determination has been made in the same manner as in the process of step S228. If the missing tooth has not been determined, the process of step S234 is repeatedly performed. If the missing tooth has been determined, the process of step S235 is performed, and then the start-time control routine ends.

According to the present embodiment in which the processing described above is performed, the following effects can be obtained. (1) When the ignition switch 52 is switched to the off position or the accessory position in order to stop the operation of the engine 11, the rotation speed of the crankshaft 14 starts to decrease. The reverse rotation occurs before the rotation of the engine 11 (crankshaft 14) completely stops, and the rotation speed of the crankshaft 14 reaches the minimum value (“0”) before the reverse rotation starts. When the engine 11 is in the stopping process, the ignition signal width Sigt gradually increases as the rotation speed of the crankshaft 14 decreases. Therefore, based on the fact that the width Sigt becomes larger than the predetermined value X2, it is possible to detect that the rotational speed of the crankshaft 14 is substantially "0" and that reverse rotation is occurring. The stop position of the crankshaft 14 can be predicted based on the reverse rotation because the crankshaft 14 completely stops at a position slightly retarded from the rotational position when the reverse rotation occurs. Since the cylinders of the cylinders # 1 to # 4 can be discriminated in the stopped state of the engine based on the predicted stop position of the crankshaft 14, the cylinder discrimination can be performed early at the time of starting the engine. Further, since it is not necessary to provide a special sensor or the like for realizing such an early cylinder discrimination, it is possible to suppress an increase in cost due to the sensor or the like.

(2) When the engine is started, the cylinder is determined based on the predicted stop position of the crankshaft 14, and the cylinder in the middle of the intake stroke is determined based on the cylinder determination. Then, immediately after the engine start command is issued, appropriate fuel injection is performed for each of the cylinders # 1 to # 4.
That is, fuel injection is performed in the cylinder in the middle of the intake stroke. Therefore, the start of the engine 11 can be completed early, and the startability of the engine 11 can be improved.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the ratio between the ignition signal width Sigt N of a predetermined cylinder and the ignition signal width Sigt M of a cylinder advanced by one stroke with respect to the same cylinder (“Sig
(t N / Sig M) is equal to or greater than a predetermined value X6 described later, and the reverse rotation of the crankshaft 14 is detected. This embodiment is different from the first embodiment in which the reverse rotation is detected based on the fact that the width Sigt of the ignition signal is larger than the predetermined value X2 in the method of detecting the reverse rotation. Therefore, in the present embodiment, only parts different from the first embodiment will be described, and detailed description of the same parts as the first embodiment will be omitted.

FIG. 14 is a flowchart showing a stop position prediction routine according to this embodiment. The stop position prediction routine of the present embodiment differs from the stop position prediction routine of the first embodiment (FIG. 6) only in the processing (steps S110 to S112) corresponding to steps S104 and S105.

In the stop position prediction routine of this embodiment,
By the processing of steps S101 to S103, S107, and S108, the same shaft 1 when the crankshaft 14 stops with the piston position of the predetermined cylinder at the top dead center
The TDC stop prediction flag F1 (n) is set according to the predicted stop position.

In the processing after step S110,
When the crankshaft 14 stops in a state where the predetermined cylinder is in the compression stroke, the stop position of the crankshaft 14 is predicted, and the stop prediction flag F2 (n) is set according to the predicted stop position. When the crankshaft 14 stops in this way, the normal rotation and the reverse rotation are repeated before the shaft 14 completely stops.

[0132] The ECU 92 determines the width S of the ignition signal in the cylinders # 1 to # 4 during the compression stroke as the process of step S110.
igt (width Sigt N) and the measured width S
igt is stored in a predetermined area of the RAM 95. ECU 92
In the subsequent step S111, the ignition signal width Sigt (width Sigt) in the cylinders # 1 to # 4 which are executing the stroke advanced by one stroke with respect to the cylinders # 1 to # 4 in the compression stroke.
M) is read from the RAM 95. Further, the ECU 92
In the process of step S112, the width Sigt N and the width Sig
It is determined whether the ratio with respect to t M (“Sigt N / Sigt M”) is equal to or greater than a predetermined value X6.

When the rotation speed of the crankshaft 14 gradually decreases during the stop process of the engine 11, each of the cylinders # 1 to # 1
The width Sigt of the ignition signal in # 4 gradually decreases. When the reverse rotation of the crankshaft 14 occurs, the rotation speed of the shaft 14 becomes “0”.
igt N is a particularly large value as compared with the width Sigt M, and their ratio (“Sigt N / Sigt M”) is equal to or greater than a predetermined value X6. Therefore, “Sigt N / Sigt M” is equal to the predetermined value X6.
Based on the above, the reverse rotation of the crankshaft 14 can be detected. The predetermined value X6 is set to a value corresponding to the ratio “Sigt N / Sigt M” immediately before the rotation speed of the crankshaft 14 becomes “0”.

If it is determined in step S112 that "Sigt N / Sigt M" is smaller than the predetermined value X6 and that the crankshaft 14 does not rotate backward, the process returns to step S101. Also, "Sigt
When it is determined that “N / Sigt M” is equal to or greater than the predetermined value X6 and the reverse rotation of the crankshaft 14 has occurred, the process proceeds to step S106. The ECU 92 sets the stop prediction flag F2 (n) according to the stop position of the crankshaft 14 predicted based on the reverse rotation as the process of step S106, and then temporarily ends the stop position prediction routine.

According to the present embodiment in which the processing described in detail above is performed, in addition to the effect (2) described in the first embodiment,
The following effects can be obtained. (3) Based on the fact that “width Sigt N / width Sigt M” is equal to or greater than the predetermined value X6, it is possible to detect that the rotation speed of the crankshaft 14 is substantially “0” and that reverse rotation has occurred. . The stop position of the crankshaft 14 can be predicted based on the reverse rotation because the crankshaft 14 completely stops at a position slightly retarded from the rotational position when the reverse rotation occurs. Since the cylinders of the cylinders # 1 to # 4 can be discriminated in the stopped state of the engine based on the predicted stop position of the crankshaft 14, the cylinder discrimination can be performed early at the time of starting the engine. Further, since it is not necessary to provide a special sensor or the like for realizing such an early cylinder discrimination, it is possible to suppress an increase in cost due to the sensor or the like.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, instead of detecting reverse rotation based on the ignition signal width Sigt, reverse rotation is performed based on the pulse signal width Sne from the crank position sensor 14c, which is a parameter that changes according to the rotation speed of the crankshaft 14. To detect. As described above, the present embodiment also differs from the first embodiment in the method of detecting reverse rotation. Therefore, in the present embodiment, only parts different from the first embodiment will be described, and detailed description of the same parts as the first embodiment will be omitted.

FIG. 15 is a flowchart showing a stop position prediction routine according to this embodiment. The stop position prediction routine of the present embodiment differs from the stop position prediction routine of the first embodiment (FIG. 6) only in the processing (steps S304 to S306) corresponding to steps S104 and S105.

In the stop position prediction routine of this embodiment,
By the processing of steps S301 to S303, S308, and S309, the same shaft 1 when the crankshaft 14 is stopped with the piston position of the predetermined cylinder at the top dead center.
The TDC stop prediction flag F1 (n) is set according to the predicted stop position.

In the processing after step S304,
When the crankshaft 14 stops in a state where the predetermined cylinder is in the compression stroke, the stop position of the crankshaft 14 is predicted, and the stop prediction flag F2 (n) is set according to the predicted stop position. When the crankshaft 14 stops in this way, the normal rotation and the reverse rotation are repeated before the shaft 14 completely stops.

The ECU 92 performs the process of step S304 in the cylinder during the compression stroke by 90 ° CA before the top dead center.
(BTDC90 °) to the top dead center (TDC) whether the signal width Sne has reached a maximum value, ie, “BTDC90
In “° to TDC”, it is determined whether or not the width Sne of the predetermined signal is larger than that of the preceding and following signals. This width S
ne increases as the rotation speed of the crankshaft 14 decreases. Then, in the determination processing of step S304, if NO, the process returns to step S301, and if YES, the process proceeds to step S305.

The situation of proceeding to step S 305 includes the following cases (I) and (J). (I) When the rotation speed of the crankshaft 14 rotating in the forward direction becomes the minimum value “0” when the reverse rotation of the crankshaft 14 occurs, and thereafter the shaft 14 starts rotating in the reverse direction (J). Missing tooth 1 on the side of crank position sensor 14c
4d passes and a pulse signal corresponding to the missing tooth 14d is output from the sensor 14c. In the above situation, the width Sne of the pulse signal from the crank position sensor 14c is a local maximum value, that is, a signal before and after. Is larger than the width Sne. Step S305,
The process in S306 is for determining which of the above (I) and (J) is the case where the width Sne of the pulse signal reaches the maximum value.

The ECU 92 determines in step S105 whether or not the maximum of the width Sne of the pulse signal is due to the missing tooth 14d based on whether or not the pulse signal corresponds to the missing tooth 14d. Judge. If the pulse signal does not correspond to the missing tooth 14d and the maximum of the width Sne is not due to the missing tooth 14d, it is determined that the maximum of the width Sne is due to reverse rotation, and the process proceeds to step S307. move on. The ECU 92 determines in step S307
The stop prediction flag F2 according to the stop position of the crankshaft 14 predicted based on the reverse rotation
After setting (n), the stop position prediction routine is temporarily terminated.

On the other hand, if it is determined in step S305 that the pulse signal corresponds to the missing tooth 14d, that is, if the situation (J) is reached, the process proceeds to step S306. .

However, when the above (J) and (I) occur simultaneously, that is, when the missing tooth 14d is located to the side of the crank position sensor 14c, the reverse rotation of the crankshaft 14 causes the shaft 14 to rotate. It is conceivable that the rotation speed becomes the minimum value “0”. Also in this case, the process of step S306 is performed so that the reverse rotation of the crankshaft 14 can be accurately determined.

[0145] In the process of step S306, when the pulse signal width Sne becomes the maximum, the ECU 92 performs the compression stroke from the top dead center (TDC) to the cylinder 90 ° CA (ATDC 90 °) after the top dead center. ), It is determined again whether or not the pulse signal width Sne has reached a maximum during the 90 ° CA. When the crankshaft 14 rotates in the reverse direction, the crankshaft 14 rotates in the reverse direction by a predetermined angle, and then reverses to the normal rotation, so that the pulse signal width Sne becomes maximum again.

Therefore, if the determination in step 306 is YES, it means that the conditions (I) and (J) are occurring simultaneously, and it is determined that the crankshaft is rotating in the reverse direction. It proceeds to S307.
On the other hand, if NO, it is determined that the situation is (J), and the process returns to step S301.

According to the present embodiment in which the processing described in detail above is performed, in addition to the effect (2) described in the first embodiment,
The following effects can be obtained. (4) Based on the fact that the width Sne of the pulse signal from the crank position sensor 14c has a maximum value, it is possible to detect that the rotation speed of the crankshaft 14 becomes "0" and reverse rotation occurs. The stop position of the crankshaft 14 can be predicted based on the reverse rotation because the crankshaft 14 completely stops at a position slightly retarded from the rotational position when the reverse rotation occurs. Since the cylinders of the cylinders # 1 to # 4 can be discriminated in the stopped state of the engine based on the predicted stop position of the crankshaft 14, the cylinder discrimination can be performed early at the time of starting the engine. Further, since it is not necessary to provide a special sensor or the like for realizing such an early cylinder discrimination, it is possible to suppress an increase in cost due to the sensor or the like.

Each of the above embodiments can be modified, for example, as follows. In the second embodiment, the width Sig of the ignition signal in a predetermined cylinder
The reverse of the crankshaft 14 is determined based on whether or not the ratio (“Sigt N / Sigt M”) of the ignition signal in the cylinder advanced by one stroke with respect to the same cylinder (“Sigt N / Sigt M”) is equal to or more than a predetermined value X6. Although it is determined whether or not rotation has occurred, the present invention is not limited to this. For example, the width Sigt N and the width Sigt M
(“Sigt N−Sigt M”) is greater than or equal to a predetermined value X7, and it may be determined whether or not the crankshaft 14 is rotating in the reverse direction. Note that the predetermined value X7 is
A value corresponding to the difference “Sigt N−Sigt M” immediately before the rotation speed of the crankshaft 14 becomes “0” with the reverse rotation is set.

The detection of the reverse rotation of the crankshaft 14 is performed based on the width Sigt of the ignition signal in the first and second embodiments, and the width Sne of the pulse signal from the crank position sensor 14c in the third embodiment. However, a method of detecting reverse rotation in a combination of these two methods may be employed. In this case, when the reverse rotation is detected by the above two methods, it is possible to suppress the erroneous detection of the reverse rotation and improve the detection accuracy by determining that the reverse rotation has occurred. .
If reverse rotation is detected by either of the above two methods, it is determined that the reverse rotation has occurred. Is not easily detected.

In the above embodiments, the crankshaft 14 is controlled based on the ignition signal width Sigt and the pulse signal width Sne from the crank position sensor 14c, which are parameters that change according to the rotation speed of the crankshaft 14.
Is detected, but the present invention is not limited to this.
That is, when detecting the reverse rotation of the crankshaft 14, a parameter that changes according to the rotation speed of the crankshaft 14 other than the above may be adopted.

In the present embodiment, the four-cylinder engine 11
However, the present invention may be applied to other multi-cylinder internal combustion engines such as six-cylinder and eight-cylinder engines.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view showing an internal structure of an engine to which a cylinder discriminating apparatus according to a first embodiment is applied.

FIG. 2 is a sectional view showing a piston and a crankshaft for each cylinder in the engine.

FIG. 3 is a block diagram showing an electrical configuration of the cylinder discriminating apparatus.

FIG. 4 is a view for explaining a stroke performed in each cylinder as the crankshaft rotates.

FIG. 5 is a diagram showing transitions of an ignition signal, a signal from a cam position sensor, and a signal from a crank position sensor for each cylinder with respect to a change in crank angle.

FIG. 6 is a flowchart showing a procedure for estimating a crankshaft stop position in the first embodiment.

FIG. 7 is a time chart showing an output mode of an ignition signal corresponding to each cylinder during a stop process of the engine.

FIG. 8 is a flowchart showing a procedure of cylinder discrimination, fuel injection control, and ignition timing control of each of cylinders # 1 to # 4 when the engine is started.

FIG. 9 is a flowchart showing a procedure of cylinder discrimination, fuel injection control, and ignition timing control of each of cylinders # 1 to # 4 when the engine is started.

FIG. 10 is a flowchart illustrating a procedure of cylinder discrimination, fuel injection control, and ignition timing control of each of cylinders # 1 to # 4 when the engine is started.

FIG. 11 is a flowchart showing a procedure of cylinder discrimination, fuel injection control, and ignition timing control of each of cylinders # 1 to # 4 when the engine is started.

FIG. 12 is a time chart showing an output mode of an ignition signal and a fuel injection mode of each cylinder, an operation mode of a starter, and a signal output mode of a cam position sensor and a crank position sensor when the engine is started.

FIG. 13 is a time chart showing an output mode of an ignition signal of each cylinder, a fuel injection mode, an operation mode of a starter, and a signal output mode of a cam position sensor and a crank position sensor at the time of engine start.

FIG. 14 is a flowchart showing a procedure for predicting a stop position of a crankshaft according to a second embodiment.

FIG. 15 is a flowchart showing a procedure for predicting a stop position of a crankshaft according to a third embodiment.

[Explanation of symbols]

11 engine, 12 piston, 14a signal rotor, 14b protrusion, 14c crank position sensor, 16 combustion chamber, 21 intake camshaft, 21a
Projection, 21b: cam position sensor, 40: fuel injection valve, 41: ignition plug, 41a: igniter, 51: starter, 52: ignition switch, 92: electronic control unit (ECU).

Claims (9)

[Claims] 1. A cylinder discriminating apparatus for an internal combustion engine which is applied to a multi-cylinder internal combustion engine having a plurality of cylinders and performs cylinder discrimination of each cylinder in an engine stopped state. A reverse rotation detection unit that detects reverse rotation of the internal combustion engine that occurs until the engine stops, and a cylinder determination unit that performs the cylinder determination based on the reverse rotation of the internal combustion engine detected by the reverse rotation detection unit. A cylinder discriminating device for an internal combustion engine. 2. The cylinder discriminating apparatus for an internal combustion engine according to claim 1, wherein said cylinder discriminating means detects a reverse rotation of the internal combustion engine based on a rotation speed of the engine. 3. The cylinder discriminating apparatus for an internal combustion engine according to claim 2, further comprising an ignition command means for outputting an ignition signal according to a rotation speed of the internal combustion engine, wherein said cylinder discriminating means outputs an output from said ignition command means. A cylinder discriminating device for an internal combustion engine that detects reverse rotation of the internal combustion engine based on an ignition signal to be transmitted. 4. A cylinder discriminating apparatus for an internal combustion engine according to claim 3, wherein said cylinder discriminating means detects reverse rotation of the internal combustion engine based on a width of an ignition signal being equal to or larger than a predetermined value. 5. A cylinder discriminating apparatus for an internal combustion engine according to claim 3, wherein said cylinder discriminating means detects reverse rotation of the internal combustion engine based on a width of a current ignition signal and a width of a previous ignition signal. 6. The cylinder discriminating apparatus for an internal combustion engine according to claim 2, further comprising: a crank position sensor that outputs a pulse-like signal according to a rotation speed of the internal combustion engine; A reverse rotation of the internal combustion engine is detected based on a pulse signal output from the internal combustion engine. 7. The cylinder discriminating device for an internal combustion engine according to claim 6, wherein said cylinder discriminating means detects a reverse rotation of the internal combustion engine based on a maximum width of a signal output from said crank position sensor. 8. A cylinder discriminating apparatus for an internal combustion engine according to claim 1, wherein fuel injection at the time of engine start is executed based on the cylinder discrimination of each cylinder in an engine stopped state by said cylinder discriminating means. A cylinder discriminating device for an internal combustion engine, further comprising an injection control means for performing the control. 9. The cylinder discriminating apparatus for an internal combustion engine according to claim 8, wherein said injection control means discriminates a cylinder in an intake stroke when the engine is stopped, and executes fuel injection in said cylinder when an engine start command is issued.