JPH01200045A - Crankshaft revolution position detector - Google Patents

Abstract

PURPOSE:To judge the cylinder group speedily and free from error by judging if the output signal of a revolution angle sensor is in any group, by a standard signal corresponding to the battery voltage level supplied into a starter. CONSTITUTION:The level of the output signal (a) of a revolution angel sensor A and the level of a standard signal (b) corresponding to the battery voltage supplied from a standard signal generating means B are compared in a comparing means C, and if a>b, a detection signal of the crankshaft revolution position is generated. Further, when an engine is started, a selecting means D sets the standard signal (b) at an H-level in the intermediate value of the output signal values of the revolution angle sensor A which correspond to a specific cylinder group and other cylinder groups, and when the output signal of the revolution angle sensor A which corresponds to the specific cylinder group is obtained, switching to a low L-level is performed. Therefore, the cylinder group is judged by a group signal generating means E from the order of generation of the detection signal of the comparing means C, and a group judgement signal is outputted.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a crankshaft rotational position detection device that uses one sensor to detect that the crankshaft of an internal combustion engine is at a specific rotational position in association with a specific cylinder. Regarding.

[Prior Art] In order to perform ignition control of an internal combustion engine, it is detected which cylinder's piston has reached compression top dead center. For this reason, for example, Japanese Patent Laid-Open No. 55-58402 discloses an angle sensor that outputs the number of pulses corresponding to the rotation angle of the crankshaft, and an M quasi-angle sensor that outputs a specific cylinder reference angle pulse for identifying the cylinder. A device is disclosed that has two sensors and uses these sensors to detect the rotational position of a crankshaft associated with a specific cylinder. Also, JP-A-57-
Publication No. 12408 discloses a device in which a rotating disk linked to the rotation of a crankshaft is provided with a different display member for each cylinder, and a rotation angle and a cylinder discrimination display are read from the rotating disk using separate sensors. .

On the other hand, a device for detecting the rotational position of a crankshaft in association with a specific cylinder using a single sensor was disclosed in Japanese Patent Laid-Open No. 56-961.
It is disclosed in Publication No. 62. This device forms a reference signal by changing the height of the teeth of a signal rotor forming a sensor. Then, it is determined whether the signal is a reference signal or not based on a fixed threshold value from the peak value of the signal detected by the electromagnetic pickup. Based on this preliminary signal, the shaft rotational position of the crank is detected in association with a specific cylinder.

[Problems to be Solved by the Invention] (1) When two sensors are used, an increase in the number of parts and an increase in cost are unavoidable.

On the other hand, in the device disclosed in Japanese Unexamined Patent Publication No. 56-96162 that uses one sensor, erroneous detection of the reference signal may occur because attention is paid to the wave IF value of the output signal of the sensor. This is because the level of the sensor's output signal changes depending on the speed, so when there is a large change in rotational speed such as when starting an internal combustion engine or racing without a load, for example, the output of the subsequent rotational angle pulse is lower than the peak value of the reference signal. This is because it may become larger.

The present invention was devised in view of the above circumstances, and is intended to detect the rotational position of a crankshaft associated with a specific cylinder without error using a single sensor.

[Means for Solving the Problems] As shown in the block diagram of FIG. 1, the crankshaft rotational position detection device according to the present invention detects at least one signal at a level corresponding to the rotational speed of the crankshaft of an internal combustion engine. The output is output at the timing when the piston of the cylinder reaches a predetermined rotation angle such as compression top dead center, and a level is set for each group to distinguish one or more specific cylinder groups from the remaining other cylinder groups. a rotation angle sensor that outputs different output signals; a reference signal generating means that generates a reference signal of a level corresponding to a voltage level of a battery that supplies electric power to a starter for starting an internal combustion engine; and an output signal of the rotation angle sensor. a comparison means for comparing the level of the rotation angle sensor with the reference signal and generating a crankshaft rotational position detection signal when the output signal of the rotation angle sensor exceeds the reference signal; Signal generation means 3! setting the quasi-signal to a high level between the output signal value of the rotation angle sensor corresponding to the specific cylinder group and the output signal value of the rotation angle sensor corresponding to the other cylinder group, and the comparison means When the output signal of the rotation angle sensor corresponding to the specific cylinder group is obtained, the reference signal of the reference signal generating means is determined from the output signal values of both the specific cylinder group and the other cylinder group. The present invention is characterized by comprising a reference signal level switching means for switching to a low level, and a group signal generating means for determining a cylinder group based on the generation order of the detection signal of the comparison means and generating a group discrimination signal.

[Operation] The rotation angle sensor outputs a signal at a level corresponding to the rotational speed of the crankshaft, and also outputs a signal at a different level for each group of cylinders. The reference signal generating means generates a reference signal at a level corresponding to the output level of the battery.

Note that the internal combustion engine according to the present invention is started by a starter that is an electric motor, and at the time of starting, the rotational speed of the crankshaft and the magnitude of the current (output) flowing through the starter have a substantially constant relationship. Therefore, the output level of the battery that supplies power to the starter and the rotational speed of the crankshaft have a substantially constant relationship determined functionally.

The reference signal level switching means, when starting the internal combustion engine,
The level of the reference signal is set to a high level between the output signal value corresponding to a specific cylinder group and the output value corresponding to other cylinder groups.

Therefore, when starting the internal combustion engine, the reference signal generating means produces a high level reference signal which has a high base and increases with the output level of the battery.

The output signal of the rotation angle sensor is compared with the high-level reference signal corresponding to the output level of the battery having a high base, and if the input output signal is higher than the reference signal, the output signal is determined to be a specific cylinder. It determines that the signal corresponds to the group and generates a detection signal.

Upon input of this first detection signal, the reference signal level switching means lowers the level of the reference signal to a value lower than the output signal value of both the specific cylinder group and other cylinder groups.
and switches to a low level that increases with the battery output level. As a result, the reference signal generating means outputs a low level detection signal corresponding to the output level of the battery.

Further, upon input of the first detection signal, the group signal generating means first outputs a group discrimination signal for a specific group.

Furthermore, the crankshaft rotates and the rotation angle sensor issues output signals corresponding to other cylinder groups. This output signal is compared with a low-level reference signal by a comparing means and determined to be a group signal. The comparison means then outputs a second detection signal. Thereafter, the comparison means outputs a detection signal by inputting an output signal corresponding to the group without distinguishing between a specific cylinder group and other cylinder groups.

Then, the group signal generating means assigns the first detection signal to a specific group, and then outputs each group discrimination signal determined according to the order of the detection signals.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a system configuration diagram showing the input/output relationship of the crankshaft rotational position detection device according to this embodiment.

As shown in FIG. 2, this system processes a crankshaft rotation angle sensor 10 and the output signal of the sensor 10 to generate a cylinder group discrimination signal and a crankshaft rotation angle signal indicating that one of the pistons is at compression top dead center. A signal processing circuit 20 that outputs an angle detection signal (corresponding to the crankshaft rotational position detection signal of the present invention), a microcomputer 100 that performs ignition νJlt1, etc., and various actuators 110, 111 . 120
．． 121.130.140.

(Description of the rotation angle sensor 10 and the signal processing circuit 20) The rotation angle sensor 10 and the signal processing circuit 20 constitute a crankshaft rotational position detection device according to this embodiment.

This rotation angle sensor 10 is a magnetic flux change detection type sensor, and is mounted on a camshaft that rotates at a ratio of 1/2 of the crankshaft. A rotor 101 having protrusions 102, 103 made of magnetic material with a similar height at intervals of 90 degrees in the circumferential direction is fixed, and a coil and magnet 104 are placed at a specific position facing the outer periphery of the rotor 101. The change in magnetic flux accompanying the rotation of the rotor 101 is detected.

The signal level of the output pulse of the rotation angle sensor 10 has an output level that corresponds to the height of the projections 102 and 103. A specific group of cylinders with a high protrusion 102 (the first and third cylinder groups of a four-cylinder engine, referred to as group A) is at a higher output level, while other cylinder groups with a lower protrusion 103 (the second and third cylinder groups of a four-cylinder engine are referred to as group A) have a higher output level. The four-cylinder group (referred to as B group) has a low output level. The output level of each group increases as the rotational speed of the crankshaft increases.

On the other hand, as shown in FIG. A comparator 22 receives the signal from the sensor 10, a base *'Fi pressure setting unit 23 that defines the threshold potential of the comparator 22, and a reference voltage corresponding to a battery output level 230 that is inversely proportional to the battery voltage. It also includes a voltage control section 24 that sets the level of this reference voltage, and a flip-flop circuit 25 that divides the frequency of the output signal of the comparator 22.

The comparator 22 serves as the comparison means of the present invention, the reference voltage setting section 23 serves as the M single signal generation means of the present invention, and the voltage control section 24 serves as the M single signal generation means of the present invention.
corresponds to the reference signal level switching means of the present invention, and the flip-flop circuit 25 corresponds to the group signal generating means of the present invention. The voltage control section 24 controls a threshold voltage of type 241 corresponding to the output level of a battery that supplies power to a starter consisting of a DC motor for starting a four-cylinder engine. As will be described later, this threshold voltage is set by switching between a high level at the beginning of startup and a low level thereafter. Here, in this embodiment, the high-level threshold voltage is lower than the high output voltage corresponding to the cylinders in the A group at the initial stage of startup among the 82 cylinder groups (A, and the low voltage corresponding to the cylinders in the B group). The low level threshold voltage is set to a value higher than the output voltage.The low level threshold voltage is set to a voltage lower than the voltage corresponding to each cylinder in the Δ and B groups.

Then, the voltage control section 24 sets the threshold voltage to a high level at the time of starting, and switches it to a low level after the first output corresponding to the cylinder of the A group is detected.

The operation of the signal processing circuit 20 will be explained below in FIGS. 4 and 5.
This will be explained with reference to the figures.

FIG. 4 is a diagram showing the relationship between the level of the output signals of the A group and the B group outputted by the rotation angle sensor 10 and the level of the threshold voltage, and the rotational speed of the crankshaft at the time of starting. FIG. 5 shows the threshold voltage V t in the signal processing circuit 2° at the time of starting.
5 is a timing chart showing changes in ho N and changes in the output signal of the circuit.

As shown in FIG. 3, when the internal combustion engine is started by a starter (not shown), the starter signal becomes a high level, and the signal processing circuit 20 enters the following initial state at the onset of this starter signal. It will be destroyed.

First, the threshold voltage V t of the reference voltage setting section 23
hoN is set to high level Vl-1.

This is to determine which cylinder in the A group or B group the output signal of the sensor 10 is from.

Further, the output signal 220 of the comparator 22 remains at a high level until the sensor output of group A is input, and the output signal 250 of the flip-flop circuit 25 is set at a low level.

The above high level threshold voltage V tllo N
is set to be approximately proportional to the battery potential. That is, the potential of the battery is correlated with the current ω supplied to the starter. On the other hand, since the starter, which is a DC motor, has a constant relationship between the amount of current and the torque, it is possible to obtain rotation that is in balance with the friction of the internal combustion engine. Therefore, it is possible to obtain a functionally determined relationship between the rotational speed of the crankshaft of the internal combustion engine and the magnitude of the starter current, or in other words, the magnitude of the battery voltage. Using this relationship, the high-level threshold voltage V th at the time of starting
o The value of N is determined. In FIG. 4, the change in the threshold voltage V tho N is shown by a two-dot chain line.

As shown in FIG. 4, a signal with a level higher than the high-level threshold voltage V tho N
When 0 is input, the comparator 22 inverts and outputs O.
- level signal, and the flip-flop circuit 25 inverts it when the output signal 220 of the comparator 22 turns on.

On the other hand, the voltage control unit 24 controls the threshold voltage V tho at the on-edge of the output signal 220 of the comparator 22.
N is switched from high level VH to low level VL.

Therefore, when the first sensor input corresponding to the A group cylinders is received, from then on, both the A group and B group The next step is to determine where each crankshaft is located.

Furthermore, since the flip-flop circuit 25 outputs a signal that is inverted when the output signal 220 of the comparator 22 is turned on, depending on whether this output signal is at a low level or a high level, the output of the comparator 22 (: the bow edge output is in the △ group It is possible to determine whether the cylinder corresponds to a cylinder in group B or a cylinder in group B.

As shown in FIG. 4, the output level of the sensor 10 and the threshold voltage for the rotation speed in terms of battery voltage change in proportion to the rotation speed on the horizontal axis. Therefore, even if the rotational speed suddenly changes during startup, the cylinders in group A and group B will not be erroneously determined during startup. Therefore, a specific cylinder group can be determined from the pulses of the cylinders of the first A group. The signal processing circuit 20 is configured to be set to an initial state when no signal from the sensor 10 is input for a predetermined period of time.

(Description of the microcomputer 100 and various actuators) As shown in FIG. @220
However, the output signal 250 of the flip-flop circuit 25 is input to the input port 102.

On the other hand, the output port of the microcomputer 100 has
Ignition device 110.111, fuel injection device 120.121
, a fuel pump 11301, a rotation control device 140, and other various actuators are connected thereto.

6 and 7 are flowcharts showing part of the interrupt processing routine of the program of the microcomputer 100. FIG.

This interrupt routine is activated by the edge input of the output signal B220 of the comparator 22 from the signal processing circuit 20, and as shown in FIG. 6, when this program is activated, in step (1100), After confirming the cause of glJ interference, step (i200> executes the subroutine for noise removal processing. This subroutine will be described in detail later.
If it is determined in step 200) that it is not noise, the process proceeds to step (1110), reads the input port and register, and checks the bit corresponding to the input level of the output signal 250 of the flip-flop circuit 25 corresponding to the cylinder group. (step i 120). Next, if the potential level indicated by the bit is not high level, the cylinder discrimination flag FSG is set to 0 (step 1140). On the other hand, if the flag is at low level, the flag FSG is set to 1'' (step 1150).

Thereafter, the process proceeds to step (i200>) and executes a subroutine that calculates the output value of the ignition signal.

This subroutine calculates the energization start and end times from the ignition timing and energization time calculated in the main routine and the input time of the edge signal. In this embodiment, two cylinders located at top dead center are ignited. Then step < +
In step 300), a subroutine for calculating the output time of the injection signal is executed, and in this subroutine, the injection energization start and injection end times are calculated from the injection time calculated in the main routine. Thereafter, in step (i160) the current contents of the register of the ignition output port are read, in step (i170) the output port is selected according to the level of the flag FSG, and in step (i400) the energization start time and current contents are read. A subroutine for calculating a time difference and setting the time difference in a conveyor register is executed, and an interrupt processing routine (not shown) is executed.

FIG. 7 is a flowchart showing details of a subroutine for noise removal processing.

In the present invention, cylinder groups are determined at the time of startup, so if the output signal of the sensor 1o is incorrectly determined due to subsequent noise or the like, there is a risk that the A group and the B group will continue to malfunction as opposite groups. From this point of view, noise removal is performed using software in addition to the input filter 21.

In step (+210), the interrupt time at which the edge input of the output signal 220 of the comparator 22 of the signal processing circuit 20 occurs is stored in the RAM, and in step (1220), the difference from the previous interrupt time, that is, the required time is stored in the RAM. demand. Next, in step (i 230>, the required time (especially the minimum time) is compared with a predetermined range that cannot occur on the system, and if it is shorter than the minimum time in step (+240>), it is determined to be noise, and step (1101 ).On the other hand, if it is longer than the minimum time, it branches to step (+250) and calculates the ratio with the previous required time, and if the change is other than a possible rotational change, for example, the ratio of the required time is 1/ If it changes to 3 or less, it is judged as noise and step (il
Branch to ol).

If it is within the normal range, the current required time is updated and stored in the RAM of the microcomputer 100 at step 1270, and at the same time, at step (+270), the current interrupt is stored in the RAM memory area where the previous time of occurrence of υ1 was stored. Update and predict the time of occurrence.

In this way, noise is determined and removed, and in step (+101), the number of cylinders in which noise has occurred is counted, and the count value is divided, and when selecting an ignition output boat as in this embodiment, Add corrections. When there are two ignition output systems, the output port is selected using the imaginary value of the cylinder discrimination flag if the count direct is an odd number, and the real value if the count is an even number.

In this example, 4 cylinders were shown, but 2 cylinders in group A and 2 cylinders in group B
The number of cylinders may be 6 cylinders in 4 cylinder groups, and the frequency may be divided into three pulses. In these cases, a specific group (A group)
is made up of two cylinders. Therefore, one cylinder in a particular group always reaches top dead center during one rotation of the crankshaft. Therefore, the ignition timing can be controlled as early as within one revolution of the crankshaft's initial movement.

Note that the number of cylinders in a specific group can also be limited to one cylinder. In this case, one specific cylinder reaches compression top dead center within two rotations of the crankshaft.

Therefore, the ignition timing can be controlled within two initial rotations of the crankshaft. In addition, in this system configuration, when a momentary power interruption occurs during operation of the internal combustion engine, the flip circuit 25
Since there is a risk that the output of the rotation angle sensor 10 may be incorrect, the connection relationship may be ensured, and an auxiliary power source may be provided, or the input of the rotation angle sensor 10 may be rectified and supplied to the power source.

[Effects of the Invention] As described above, according to the present invention, by the reference signal corresponding to the battery potential level supplied to the starter,
The output signal of the rotation angle sensor is used to determine which group the cylinder belongs to.

Therefore, it is possible to determine which group of cylinders the output signal of the rotation angle sensor belongs to within two initial rotations of the crankshaft. Furthermore, even if the rotational speed fluctuates during startup, the level of the reference signal changes accordingly, so that false detection does not occur. Further, the cylinder group is determined at the time of startup, and thereafter, due to this determination, erroneous detection does not occur even if there is a sudden change in the rotational speed of the crankshaft in order to determine the cylinder group of the output signal of the rotation angle sensor.

[Brief explanation of the drawing]

Figure 1 shows the place where the present invention is based! 2 is a system configuration diagram showing the input/output relationship of the crankshaft rotational position detection sensor according to the embodiment of the present invention, FIG. 3 is a functional block diagram of the signal processing circuit + ti420, and FIG. is a graph showing the relationship between the output signal level and threshold voltage of the sensor 10 corresponding to the A group and the B group, and the rotational speed of the crankshaft. FIG. 5 is a quimming test showing changes in the threshold voltage of the signal processing circuit and changes in the output signal of the circuit during startup. FIG. 6 is a flowchart for ignition output processing by the microcomputer, and FIG. 7 is a flowchart for a subroutine for noise removal. 10... Rotation angle sensor 20... Signal processing circuit 2
2...Comparator 23...3J quasi-voltage aQ constant section 24...Voltage control section 25...Flip-flop circuit hood, 'tri

Claims (1)

[Claims] (1) Output a signal at a level corresponding to the rotation speed of the crankshaft of the internal combustion engine at the timing when the piston of at least one cylinder reaches a predetermined rotation angle such as compression top dead center, and output a signal at a level corresponding to the rotation speed of the crankshaft of the internal combustion engine, and A rotation angle sensor that outputs an output signal with a different level for each group to distinguish between the cylinder group and the remaining cylinder groups, and a rotation angle sensor that outputs an output signal with a different level for each group, and a sensor that corresponds to the voltage level of the battery that supplies power to the starter for starting the internal combustion engine. a reference signal generating means for generating a level reference signal; and comparing the level of the output signal of the rotation angle sensor with the reference signal, and when the output signal of the rotation angle sensor exceeds the reference signal, the crankshaft is rotated. a comparison means for generating a position detection signal; and when the internal combustion engine is started, the reference signal of the reference signal generation means is compared with the output signal value of the rotation angle sensor corresponding to the specific cylinder group and the other cylinder group. The reference signal is generated when the comparison means obtains an output signal of the rotation angle sensor corresponding to the specific cylinder group. reference signal level switching means for switching a reference signal of the means to a low level lower than output signal values of both the specific cylinder group and the other cylinder group; group signal generation means for determining a group determination signal and generating a group determination signal;
A crankshaft rotational position detection device comprising: