JPH0135281B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an apparatus for measuring the rotation angle between a reference angular position of an engine shaft and an angular position of the engine shaft at the time of occurrence of an event based on engine operating conditions, the apparatus comprising: pieces of stroboscopes, etc.
a plurality of pulses comprising a first oscillator responsive to a reference angular position and also including noise pulses sent to an evaluation unit based on the output of a second oscillator influenced by an event characterizing the engine; a sensing circuit to which the second transmitter is connected, the evaluation unit producing an angle-proportional signal from the time interval between the reference angular position and the event characterizing the engine; The present invention relates to a device comprising a comparator having a first input for determining a threshold value for detecting the event and a second input for receiving a signal for determining a threshold value for detecting the event.

An example of this type of device is a device that measures the timing of fuel injection by taking advantage of the fact that in an operating engine, the fuel conduit pressure increases significantly during fuel injection. The pressure increase during fuel injection is quite large, but this pressure measurement signal is superimposed with steep-rising noise, such as sparks from an igniter, induced from the outside, and this noise is generated before the event occurs. also exists. Therefore, even if you try to detect the rising point of the pressure signal during fuel injection, which has a slower rising characteristic,
If the threshold value of the comparator used for determination is set low, it will be confused by noise, and if it is set high, detection will be delayed significantly from the rise time, making it extremely difficult to automatically determine accurately online. . Details are described below.

In devices of this type, there is a problem in producing a trigger signal derived from data characterizing engine characteristics, such as injection line pressure. This trigger signal is utilized in conjunction with a second trigger signal responsive to a predetermined angular position of the crankshaft to create a gate signal that is counted.

The trigger signal is derived from the pressure curve relationship, but ideally it should be generated at the time of the first pressure rise in the injection line that occurs each stroke cycle. However, in order to avoid the fact that noise signals, which are always present, cause the triggering action to take place several times, e.g. before a real pressure rise, the triggering action must be triggered only when a predetermined pressure threshold in the injection line is exceeded. It is necessary to create a pulse. This is not difficult, as various methods are already known, and use a voltage comparator controlled by a shaped injection line pressure signal to determine its response level before the pressure rise. You just need to set it so that it exceeds the noise level. However, if the noise preceding the pressure rise is large, the response level of its comparator must also be selected to be large, which is far from the ideal requirement to produce a trigger pulse at the onset of the pressure rise. It becomes a thing.

By definition, spurious noise is said to exist if a set threshold or pressure value is exceeded and then dropped again before the distinct occurrence of an event characteristic of the engine characteristics, ie a pressure increase.

In addition, the Federal Republic of Germany Patent Application Publication No.
A method already proposed in the patent specification 2347800 is to connect an integrator to the output of such a signal oscillator and connect the integrator to a threshold switch. According to this, spurious pulses whose time-integrated voltage value is less than a predetermined value, that is, the response threshold of the threshold switch, are eliminated. However, in reality, this configuration is only suitable for noise that is high in voltage level but connected only for a very short time, such as when a pseudo signal is mixed into a long transmission path. A further disadvantage of this circuit configuration is that the evaluation of the signal to be selected is subject to a time delay that is dependent on a response threshold tuned to the time integral of the voltage of the signal to be selected and rejected. This will be accompanied by the following. In this way, the time delay depends on the waveform of the input signal and is never determined by the duration.

The object of this invention is to provide a strategy that allows the generation of trigger pulses as close to ideal conditions as possible, even in the presence of large noises preceding the signal indicating the onset of a true engine event. It is to be. To solve this problem, the evaluation unit logically combines the output signal of the comparator, which has a threshold that can be exceeded even by noise signals or spurious signals, with the output signal of the sensing circuit, which corresponds to an event characterizing the engine. It is connected to a logic circuit which calculates the time period between the input of the reference angular position signal and the last time the signal exceeded the threshold at the input of the comparator before the occurrence of said sensing circuit. The arrangement is such that the distance is determined and used by the evaluation unit to determine the rotation angle.

If the output level from the comparator output section exceeds the comparator response level every time a signal occurs, even if noise occurs, then the output level is, for example, "low".
If the response level is lower than the response level, the response is switched from "high" to "low". Therefore, each time the comparator output level switches from "low" to "high", the evaluation unit is activated by the logic circuit connected to the output of the comparator and the output of the comparator is Each time the level changes from "high" to "low" the evaluation unit can be stopped and reset. Such a process ensures that the switching of the output level of the comparator from ``low'' to ``high'' no longer occurs as a noise or spurious signal, but as a characteristic signal of the engine, such as an increase in injection line pressure. is repeated until it occurs. When the output level of the comparator switches from "low" to "high" with a true signal, the output signal of the sensing circuit causes the evaluation operation to continue through the logic circuit until the reference rotation signal is input.

Such a measure according to the invention makes it possible to keep the threshold of the comparator low so that the evaluation operation can start immediately after the signal is generated. Furthermore, according to the sensing circuit of the present invention, it is possible to determine whether the signal is a pseudo signal or not during the evaluation operation, and if it is a pseudo signal, the evaluation operation is reset or not restarted from the beginning. Then you can configure it. In addition, if it is not noise or a pseudo signal, the evaluation operation of the sent signal can be delayed for a predetermined period of time, during which time it can be verified whether it is a signal to be used or not, and the reference angle signal can also be evaluated for the same period of time. It can be delayed. It is thus ensured that in this measurement the time interval between the onset of the characteristic signal of the engine and the reference angle signal generated, for example at the top dead center of the piston of the engine, is fully taken into account.

In this way, in the present invention, a sufficiently low threshold is set for the first comparator, which has a low threshold that can even exceed the noise signal, so that the signal does not rise even if it is mixed in with the noise. It is designed to generate a detection signal as soon as the engine is affected, and is often used as the threshold of a second comparator with a high threshold built into the sensing circuit that is sensitive to events characterizing the engine. The size is selected and set so that it eliminates almost all noise and detects the event.

By doing this, the second comparator can accurately determine the presence or absence of a rising edge of the main signal even if it is insensitive and detect the occurrence of an event, and the first comparator can quickly catch the rising point and start the process. Appropriate division of labor and integration is performed to detect points in time with high sensitivity. Further, even when noise is mixed in before an event occurs, it can be determined online by performing a logical operation with the output of the second comparator. In this way, it becomes possible to accurately identify the time when an event occurs.

In addition, in conventional methods, if the threshold value of the comparator used to remove noise and determine the target signal is too low, the noise cannot be separated, and if it is too high, the capture of the target signal will be delayed. Due to this inherent nature, it has been difficult for designers to determine the threshold value that will prevent them from making a mistake in distinguishing between the two. On the other hand, in the present invention, as described above, since both are determined using separate threshold values, the set value can be easily determined.

In constructing the device according to the invention, the evaluation unit essentially consists of a counter into which a signal corresponding to the angle value is input, the counter being set at a low threshold that can be exceeded even by a noise signal. set by a signal corresponding to an input above this threshold in a comparator that has been set, and reset to zero by a reset signal produced by a signal corresponding to an input below the threshold of that comparator; An advantage can be obtained if the counting operation of the counter continues after the sensing circuit is triggered and is stopped by the reference angle signal or a signal generated based on the reference angle signal.

The evaluation unit with this configuration is characterized by a particularly simple structure and reliable operation. Furthermore, it is advantageous if the evaluation unit is a computer for further evaluation of the determined angle values.

As a characteristic embodiment of the invention, the sensing circuit comprises another comparator (hereinafter referred to as second comparator) and a monostable multivibrator connected to the output side of this second comparator. the input of said second comparator is connected to the input of said first comparator which also sets and, if necessary, resets the counter; Some response thresholds (A) exceed those of the first comparator. According to this configuration, the characteristic signal of the engine can be detected reliably in a very simple way, and the response threshold can be selected relatively high, so that the characteristic signal of the engine can be sensed before the true characteristic signal of the engine. It is ensured that the appearing spurious signals do not change the comparator switching state of the sensing circuit. The monostable multivibrator connected to the output side is furthermore designed in such a way that only one signal is input to the logic circuit during each operating cycle, i.e. it suppresses the characteristic signal of the engine by reflection phenomena. The purpose is to prevent spurious signals that appear behind the circuit from influencing the logic circuit, although they reach a considerable level.

There are further various configurations of sensing circuits. In some cases, the circuit is made up of a differentiating circuit, which outputs a signal corresponding to the increase in signal level, and the signal is verified both for its level value and for a predetermined minimum duration, to determine the characteristics of the engine. It is possible to distinguish a characteristic signal from noise as a pseudo signal, and if it is a characteristic signal, the signal can be input to a logic circuit. Furthermore, it is often possible to distinguish between spurious signals that are noise based on the fact that only the spurious signals are below a predetermined minimum duration.

As another preferred embodiment,
The sensing circuit comprises a second comparator and an integrator switch connected to the output of the second comparator, the input of the second comparator also setting and, if necessary, resetting the counter. the first with a lower threshold
is connected to the input of the comparator, the response threshold of the second comparator is above that of the first comparator, and the integrator switch is connected to the input of the second comparator. The integrator is reset, interrupted or set depending on the switching state of the second comparator, and the output of the integrator is connected to the first input of a further third comparator and the peak hold means. and a third one is connected to the output side of the peak hold means.
Some have a voltage divider connected to the second input of the comparator, the intermediate tap of which is connected to the second input of the comparator.

The reference reference signal for the above-mentioned first comparator and possibly the second comparator of the sensing circuit may vary from the absolute constant value even from the peak value of the characteristic signal of the engine. But it is possible to create it.

In yet another embodiment, the sensing circuit comprises a second comparator and an AND gate, the input of the second comparator having a lower threshold value. The AND gate is connected to the input section and has a response threshold larger than that of the first comparator, and the AND gate is connected to the output side of the first comparator, such as a retriggerable multivibrator. The AND gate performs a logical operation on the output of the timing circuit and the output of the second comparator, and furthermore, the AND gate sets a counter constituting the evaluation unit and also has a correction circuit, which is limited by the timing circuit. Some devices are constructed of a monostable multivibrator or the like which is interposed between the reference angle transmitter and the evaluation circuit and which compensates for the delayed start of the counter.

In this embodiment, the multivibrator connected to the first comparator and the multivibrator connected to the first oscillator that emits a signal at the reference angular position have equal delay times, so the AND A bistable multivibrator is set at the timing of the final falling edge of the output pulse of the gate, and the bistable multivibrator is reset at the timing of the final falling edge of the output pulse of the second multivibrator. If the evaluation unit is activated, the time interval from the occurrence of the event to the input of the reference angle signal is given accurately, so that an accurate rotation angle can be determined.

As a very simple embodiment example of the conversion of a gate signal defined by a characteristic signal of the engine and a reference angle signal, the counting input of the counter constituting the evaluation unit is constant with the engine axis or with this engine axis. Some devices are connected to a transmitter that responds to angle marks provided on a rotating disk or the like that rotates at a rotational ratio.

In a structurally simple embodiment of the measuring device according to the invention, the counting input of the counter constituting the evaluation unit is connected to a frequency multiplication circuit, which multiplies the angular resolution. The product α・of the degree k and the angle α between the two reference angle marks
There is one in which the signal obtained from the reference angular position is multiplied by k.

When the requirements for resolution and measurement accuracy are particularly high, it is preferable to input pulses at a constant frequency to the counting input section of the counter constituting the evaluation unit, and the counter is connected to the arithmetic unit. , rotation information is sent as second information to the calculation device by a method such as measuring pulses captured at the same frequency between two reference angle signals, and the rotation angle is calculated by dividing the two values. There are some cases where a value proportional to is required. According to this configuration, the transmitter for detecting the reference angular position of the shaft is sufficiently satisfactory from the viewpoint of engine structure, and the structure can be extremely simple.

In order to be able to carry out further arithmetic processing in a simple manner on the angle proportional signal obtained in the evaluation circuit, a storage device is connected to the output of the counter, which storage device can be read by the reference angle signal. There is a configuration in which the counting information is received from the counter after inputting the signal or a signal derived from the signal.

Next, the present invention will be described in more detail with reference to the accompanying drawings.

Examples Events that characterize an engine (hereinafter referred to as engine characteristic phenomena), such as an increase in pressure in the injection pipe,
A signal sent from an oscillator for detecting is inputted to a peak hold 2 and two comparators 3 and 4 via a capacitive coupling circuit 1. The comparators receive a reference voltage at their respective second input terminals, which reference voltage is generated by a voltage divider 5 on the basis of the peak value of a signal, for example a pressure signal. The second comparator indicated by 3 has a reference voltage A which is, for example, 65% of the pressure signal peak value.
, and the first comparator, designated 4, receives a reference reference voltage B, which is, for example, 17% of its peak value. The output voltages of both comparators 3 and 4 are shown in FIG. A monostable multivibrator 6 is connected to the output of the second comparator 3, which ensures that only one pulse per operating cycle in the injection line is obtained as the output of the multivibrator 6. It is something. The second comparator 3 and this monostable multivibrator 6 together make up a sensing circuit. This multi vibrator 6
The bistable multivibrator 7 is controlled by the output pulse and the reference position pulse which is supposed to be sent out from the reference position transmitter, for example, at the top dead center of the piston. The output signal of the bistable multivibrator 7 is shown in FIG. A monostable multivibrator 8 is also connected to the output side of the first comparator 4, which is
As shown in FIG. 2, one short pulse is output for each falling edge of the first comparator output signal.

The output signals of both multivibrators 7 and 8 are input to an AND gate 9, and the AND gate sends out a zero return reset signal for the counter 10 as its output. This bistable multivibrator 7
The respective output signals of and the first comparator 4 are ORed.
It is input to gate 11, but the
There is also an inverter 14 in front of the input terminal connected to the bistable multivibrator 7 of the OR gate.
is interposed. The output signal of this OR gate 11 is used as a signal to start counting angle mark pulses. The angle mark pulses correspond, for example, to intervals of, for example, 0.1° of the shaft rotation angle and are input together with the aforementioned signals to a counter 10 forming an evaluation unit.
A storage device 12 connected to the output side of the counter 10 is a monostable multivibrator which outputs one short pulse each time the output signal of the multivibrator 7 rises, which is controlled by the output of the multivibrator 7. A command to capture the counting state of the counter 10 is given from the output terminal of the breaker 13. In the storage device 12, information corresponding to, for example, the fuel feed start angle is stored until a new angle value for the next working stroke is created, and can be easily read out for arithmetic processing. It goes without saying that
A fixed reference value can also be input into the first comparator 4, which corresponds to a pressure of 30 bar, for example.

As another embodiment of the invention, the counter 10
There is a method in which pulses of constant frequency f ₁ are counted instead of angle mark pulses, and the binary information of the measured pulses is input to an arithmetic unit. The arithmetic unit receives, as second information, rotational speed information, for example information generated at the same frequency f ₁ within the time between two reference position signals;
is input. Angular information can be obtained by performing a division operation on the two pieces of binary information inputted to the arithmetic unit and multiplying by a predetermined coefficient that defines the degree of resolution.

In the embodiment according to FIG. 3, both comparators 3, 4
However, the respective reference values and signals sent from the oscillator are provided on the input side via the capacitive coupling circuit 1, peak hold 2, and voltage divider 5. A retriggerable monostable multivibrator 6' is connected to the output side of the low threshold comparator 4, the output of which is connected to an AND gate 15, the second input terminal of which It is connected to the output of the second comparator 3 which is set to the value.

The output terminal of this AND gate 15 is connected to a first input terminal of a bistable multivibrator 17, whose second input terminal is connected to a monostable multivibrator 16 controlled by a reference position pulse, It has the same operating time as the multivibrator 6' mentioned above.

The output of the bistable multivibrator 17 controls the counter 10, which is connected to the separately generated angle mark pulse by the AND gate 1.
A storage device 12 is connected to the output side of the multivibrator 9, and the storage device is controlled by a signal input from the multivibrator 16 mentioned above. Import the counting status of.

When the threshold of the first comparator 4 is exceeded, the multivibrator 6' is triggered to switch;
For example, a logic 0 is output to the output terminal. If the threshold of the second comparator 3 is exceeded within its activation time, i.e. the time that begins every time there is a signal of its multivibrator 6' which corresponds to an exceeding of the threshold, both of them The comparators 3 and 4 output logic 1 when their respective thresholds are exceeded, and the AND gate 15 waits for the activation time of the multivibrator 6' to output a signal to switch the bistable multivibrator 17. At the same time that the multivibrator sets the counter 10 to start, input of the angle mark pulse to the counter 10 is permitted.

When the reference position pulse is input here, the multivibrator 16, which has the same operating time as the multivibrator 6', is triggered.

After waiting for the operating course of the multivibrator 16, the bistable multivibrator 17 is switched by means of a switching signal side generated by its return switching, and the passage of the angle mark pulse to the counter 10 is no longer prevented. After waiting for the activation time of the delay time element 18 to elapse, the counter 10 is reset to zero.

The switching effect signal generated by switching back the multivibrator 16 causes the counting state to be stored in the memory 12 prior to such a reset of the counter 10.
It serves the purpose of storing things inside. Thus, in this embodiment, although the start of the evaluation operation is delayed by a certain elapsed time regulated by the multivibrator 6', the reference position pulse is also delayed by the same time interval by the multivibrator 16, and Therefore, they will be compensated.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of a preferred embodiment, FIG. 2 is an output voltage curve at various numbers in the circuit configuration of FIG. 1, and FIG. 3 is a configuration diagram of another embodiment of the present invention. It is. 1... Capacitive coupling circuit, 2... Peak hold,
3... second comparator, 4... first comparator, 5...
... Voltage divider, 6 ... Monostable multivibrator, 7
...Bistable multivibrator, 8...Monostable multivibrator, 9...AND gate, 10...
...Evaluation unit whose configuration example is a counter, 11...
OR gate, 12... Storage device, 13... Monostable multivibrator.

Claims (1)

[Scope of Claims] 1. A device for measuring a rotation angle between a reference angular position of an engine shaft and an angular position of the engine shaft at the time of occurrence of an event based on engine operating conditions, including: one transmitter and a second transmitter influenced by events characterizing the engine.
oscillator, and a first oscillator that compares and determines the output of the second oscillator with a low threshold value (B) that can exceed even a noise signal.
a sensing circuit that detects and outputs the occurrence of the event by a second comparator 3 that compares and determines the output of the second oscillator with a high threshold value (A); The output of the first oscillator, the judgment output of the first comparator, and the output of the sensing circuit are input, and the judgment output signal of the first comparator is output at the end before the output signal of the sensing circuit is generated. a logic circuit that calculates the time interval from the time when the output signal of the first oscillator is input; and a logic circuit that calculates the time interval between the reference angular position and the event occurrence position based on the time interval calculated by the logic circuit An engine shaft rotation angle measuring device comprising: an evaluation unit that generates a signal corresponding to a change in angle. 2. The evaluation unit starts counting the counting input at the rising edge of the judgment output of the first comparator 4, and starts counting at the falling edge of the judgment output of the first comparator unless the output of the sensing circuit is input. 2. The apparatus according to claim 1, comprising a counter 10 which returns to zero and stops counting in response to an output signal from the first oscillator. 3. According to claim 1 or 2, the threshold value (B) of the first comparator 4 is a constant percentage of the peak value of the signal corresponding to the event characterizing the engine. The device described. 4. The device according to claim 1 or 2, wherein the threshold value (B) of the first comparator 4 is an absolute value that is kept constant. 5 said sensing circuit comprises a second comparator 3 and a timing circuit 6 connected to the output of said comparator, the input of said second comparator being connected to said first comparator;
is connected to the input part of the comparator 4, and the threshold value (A) of the second comparator is higher than the threshold value (B) of the first comparator. An apparatus according to claims 1 to 4. 6. The sensing circuit includes the second comparator 3 and an integrator switch connected to the output side of the comparator, and the input section of the second comparator is connected to the first comparator 4. , the threshold value (A) of the second comparator exceeds the threshold value (B) of the first comparator, and the integrator switch is connected to its input side. a voltage integrator is reset, interrupted or set depending on the switching state of said second comparator connected to said integrator; A voltage divider is connected to the peak hold means, and the output side of the peak hold means is connected to a voltage divider whose intermediate tap is connected to the second input of the third comparator. An apparatus according to claims 1 to 4. 7. The count input section of the counter 10 constituting the evaluation unit is connected to a transmitter that responds to an angle mark provided on the engine shaft or a rotating disk or the like that rotates at a constant rotation ratio with the engine shaft. Claims 1 to 6 are characterized in that:
Equipment described in Section. 8. The counting input section of the counter 10 constituting the evaluation unit is connected to a frequency multiplier circuit that receives as input the output of an oscillator that responds to an angle mark interlocked with the engine shaft, and the frequency multiplier circuit is the resolution k per angle unit and the angle α between the two angle marks
8. Device according to claim 7, characterized in that the signal obtained from the angle mark is multiplied by the product α·k. 9. The evaluation unit is composed of a counter and an arithmetic device, and pulses of a constant frequency are inputted to the counting input section of the counter 10, and the counted value is supplied to the arithmetic device, and the count value is supplied to the arithmetic device. is the second
Rotation information is sent as information by a method such as measuring pulses captured at the same frequency between two appropriate angle marks, and a value proportional to the rotation angle is obtained by dividing the two values. An apparatus according to any one of claims 1 to 6, characterized in that: 10 A storage device 12 on the output side of the evaluation unit.
is connected to the evaluation unit, and the storage device receives the count contents from the evaluation unit when a reference angular position signal or a signal derived from the signal is input. The device described. 11 The logic circuit is connected to the second comparator 3.
The input section of the second comparator is configured to include an AND gate 9, and the input section of the second comparator is connected to the first one having a lower threshold value (B).
The AND gate is connected to the input part of the comparator 4 and has a threshold value (A) larger than that of the first comparator, and the AND gate is connected to the output side of the first comparator. The output of the first retriggerable timing circuit 8 and the output of the second comparator are logically operated, and the AND gate sets the evaluation unit and also includes a correction circuit, and the AND gate sets the evaluation unit and also includes a correction circuit. is characterized in that it comprises a monostable multivibrator 13 which compensates for the limited and delayed start of the evaluation unit by a timing circuit and which is interposed between the first oscillator and the evaluation circuit. Claim 1:
The apparatus described in any one of Items 4 to 4 and 7 to 10. 12. The device according to claims 1 to 11, characterized in that the functions of the logic circuit are performed by a microcomputer.