JPH0321815A - Crank angle detector for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve an engine control characteristic at the engine starting time by constituting so as to include crank angle detecting means, reference angle position detecting means and invalidation processing means for specified period. CONSTITUTION:Detected pulse signals rising at each reference angle position of crank shaft are outputted by the crank angle detecting means (a). By the reference angle position detecting means (b), the rises of detected pulse signals are discriminated to detect the reference angle position by means of comparing the detected pulse signal and a reference slice level. The detection of reference angle position according to the reference angle position detecting means (b) is invalidated for the specified period from the engine starting time by the invalidation processing means (c) for specified period, when the detected pulse signal outputted from the crank angle detecting means (a) is in high level at the engine stopping condition. That is, when a misdetection for rise is probable to occur immediately after the start, various controls such as a fuel supply control, etc. and the calculation based on the abovementioned rises are made to be cancelled.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a crank angle detection 76H for an internal combustion engine, and particularly to a device that improves detection accuracy when starting the engine.

Conventional technology> Conventionally, internal combustion engines configured to electronically control fuel supply timing, ignition timing, etc. are equipped with a crank angle detection device, and various engine control timings are determined based on the crank angle position detected by this device. (Refer to Japanese Unexamined Patent Publication No. 59155540, etc.). As a crank angle detection device, for example, a signal plate that rotates in synchronization with the engine rotation may be placed on the same circumference, corresponding to the reference angular position of the crankshaft (for example, in a 4-cylinder engine, 4 locations at 180° intervals). By forming a slit, sandwiching this signal plate, installing a light source on one side and a detection section on the other, and detecting the light passing through the slit with the detection section, a high level pulse is generated when the light passing through Surinoto is detected. There is an optical crank angle sensor configured to output a signal. Then, set the rise of the pulse signal output from such a crank angle sensor so that it corresponds to the reference angle position that you want to detect, and determine the rise of the pulse signal by comparing it with the slice level, and set the crankshaft reference. The angular position is detected.

As shown in FIG. 8, engine control performed upon detection of such a reference angular position includes, for example, control of fuel supply start timing to start fuel supply by a fuel injection valve or the like when the reference angular position is detected. There is. In the example shown in Figure 8,
When the engine is started, fuel injection is started for a predetermined period of time at the first rise of the pulse signal, no fuel is supplied at the next rise, and fuel is supplied again at the second rise. , thereafter, fuel is supplied only once for every two rising edges of the pulse signal. <Problems to be Solved by the Invention> By the way, when the engine is stopped and the pulse signal from the crank angle sensor is at a high level, a large voltage is generated by driving the starter motor (starter motor) to start the engine. When a drop occurs, as shown in Figure 9, due to the influence of this voltage drop, the pulse signal of the crank angle sensor also drops regardless of the crank angle, and the signal level drop due to this voltage drop is restored. Sometimes, it cannot be distinguished from the normal pulse rise, resulting in a state in which the reference angular position is detected.

In this way, if the reference angular position is erroneously detected, excess fuel will be supplied in the TM system that supplies fuel at each reference angular position as described above, and the fuel supply at the time of starting the engine There is a problem that accuracy deteriorates and startability deteriorates.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to avoid erroneous detection of the reference angle position due to voltage drop at the time of starting the engine, and improve engine controllability at the time of starting the engine. .

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. a reference angular position detection means for detecting the reference angular position by determining the rising edge of the detection pulse signal by comparing it with a slice level of the engine; and a detection pulse signal output from the crank angle detection means when the engine is stopped. The crank angle detecting device is configured to include a predetermined period invalidation processing means for disabling the detection of the reference angular position by the reference angular position detecting means for a predetermined period from the start of the engine when the crank angle is at a high level.

Further, as shown in FIG. 2, a crank angle detection means outputs a detection pulse signal that rises at each reference angle position of the crankshaft, and a detection pulse signal is detected by comparing the detection pulse signal with a predetermined slice level. a reference angular position detecting means for detecting the basic angular position by determining a rise; a power supply voltage detecting means for detecting the power supply voltage of the crank angle detecting means; Voltage drop invalidation processing means for invalidating the detection of the reference angular position by the reference angular position detection means when the detection pulse signal is at a high level and the power supply voltage detected while the engine is rotating is below a predetermined value. and,
The crank angle detection device may be configured to include the above.

According to this configuration, the crank angle detection means outputs a detection pulse signal that rises at each reference angular position of the crankshaft, and the reference angular position detection means compares this detection pulse signal with a predetermined slice level for detection. The reference angular position is detected by determining the rising edge of the pulse signal.

On the other hand, the predetermined period invalidation processing means disables the detection of the reference angular position by the reference angular position detection means for a predetermined period from the start of the engine when the detection pulse signal is at a high level when the engine is stopped, and detects the reference angular position. Even if the rising edge of the detection pulse signal is detected by the means, if there is a possibility of false detection of the rising edge during the predetermined period, in other words, immediately after starting, various controls and calculations such as fuel supply control based on the rising edge are canceled. to be done.

In addition, instead of disabling the rise detection for a predetermined period after starting as described above, the voltage drop disabling processing means
When the power supply voltage of the crank angle detection means detected by the power supply voltage detection means is below a predetermined value while the engine is rotating, and the detection pulse signal is at a high level when the engine is stopped, the reference angle position detection means detects the reference value. Disable angular position detection. In other words, when the detection pulse signal is at a high level when the engine is stopped, there is a high possibility that the rise will be erroneously detected when the voltage drops below a predetermined value while the engine is rotating. Even if the rise of the voltage is detected, various controls and calculations such as fuel supply control based on the detection of the rise at the time of voltage drop are canceled.

<Example> Examples of the present invention will be described below.

In FIG. 3 showing one embodiment, an engine 16 is connected to an air intake duct 3 from an air cleaner 2. Air is taken in via the throttle valve 4 and the intake manifold 5. A fuel injection valve 6 is provided in a branch portion of the intake manifold 5 for each cylinder. The fuel injection valve 6 is an electromagnetic fuel injection valve that opens when the solenoid is energized, and closes when the energization is stopped, and opens when it is energized by a drive pulse signal from the control unit 12, which will be described later. Fuel is injected and supplied under pressure from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator.

An ignition plug 7 is provided in the combustion chamber of the engine 1, which ignites a spark to ignite and burn the air-fuel mixture. and,
Exhaust gas is exhausted from the engine l via an exhaust manifold 8, an exhaust duct 9, a three-way catalyst lO, and a muffler 11.

The control unit 12 includes a CPU, ROM. RAM
, an A/D converter, and a human output interface, the microcomputer receives input signals from various sensors, performs arithmetic processing as described below, and controls the operation of the fuel injection valve 6.

As the various sensors, a hot wire type or flap type air flow meter l3 is provided in the intake duct 3, and outputs a voltage signal corresponding to the intake air flow rate Q.

In addition, a crank angle sensor l4 is provided as a crank angle detection means for detecting the reference angular position of the crankshaft using an optical method or a power generation method.
A reference angle signal REF (detection pulse signal) that rises every 80" (for example, every reference angle position of each air intake B'rDC90°) is output.

It should be noted that the detection method of the crank angle sensor 14 is not limited; it may be any type that generates a pulse signal that rises at a certain time with the rotation of the crankshaft.Furthermore, it can detect the cooling water temperature Tw of the water jacket of the engine l. A water temperature sensor l5 and the like are provided. Further, an oxygen sensor l6 is provided at the gathering part of the exhaust manifold 8, and detects the air-fuel ratio of the air-fuel mixture taken into the engine 1 via the oxygen concentration in the exhaust gas.

A battery 17 is connected to the control unit 12 as its operating power source and for detecting the power supply voltage Vll through an ignition switch (IC/SW) 1B, and a start switch (not shown) that controls the drive of a starter motor (not shown). START/SW) 19 ON
-OFF signal is input. Here, the control unit l2 detects the rise of the detection pulse signal at the reference angle position by comparing the reference angle signal REF (detection pulse signal) output from the crank angle sensor 14 with a predetermined slice level. Then, a basic fuel injection amount Tp is calculated based on the engine rotational speed N and the intake air flow rate Q, which are calculated based on the rising cycle, and this basic fuel injection! 'T'p is corrected based on the cooling water temperature Tw, exhaust oxygen concentration, etc., and the final fuel injection i
1Ti, and outputs a drive pulse signal having a pulse width corresponding to the fuel injection amount Ti to each fuel injection valve 6 at a predetermined injection timing based on the rise of the reference angle signal REF.

In addition, in the starting state of the engine 1 determined by the start switch 19, the drive pulse signal in the pulse corresponding to the starting fuel injection fiTist set based on the cooling water temperature Tw is input to the reference angle signal REF. It is configured to simultaneously output to all the fuel injection valves 6 once every two times when the rise of the fuel injection valve 6 is detected.

Next, a fourth embodiment of the crank angle detection device according to the present invention will be described.
The routine will be explained according to the flowcharts shown in FIGS. In this embodiment, the functions of the reference angular position detection means, the predetermined period invalidation processing means, the power supply voltage detection means, and the voltage drop invalidation processing means are controlled as shown in the flowcharts of FIGS. 4 to 6. Unit 2 has it.

The routine shown in the flowchart of FIG. 4 shows the first embodiment of the crank angle detection device according to the present invention. First, in step 1 (indicated as SI in the figure; the same applies hereinafter), the ignition switch 18 is turned on. ON・OF
F is determined, and if it is ON, it is determined in step 2 whether the engine 1 is rotating or not, and if the ignition switch 18 is OFF F', this routine is directly terminated.

When it is determined in step 2 that engine 1 is rotating, is the reference angle signal in the engine stopped state? Since the level of EF cannot be determined, this routine is ended as is, but if it is stopped, the process proceeds to step 3 and the level of the reference angle signal REF is determined.

When it is determined in step 3 that the reference angle signal REF is high, for example, in an optical crank angle sensor, the engine is stopped due to the positional relationship in which the light from the light emitting element or the light receiving element is irradiated. Step 4
Proceed to step 1 and determine the basic time 1゛■ for determining the time 1゛■ for which the rise detection of the pulse signal is masked and invalidated.
, is determined by referring to a preset map based on the voltage vIl of the Hatte 1 River 7. Here, the required basic time ``■'' is set to be longer as the voltage ``3'' of the battery 17 is lower and the voltage drop time due to driving of the starter motor is longer.

Further, in the next step 5, the basic time 'l.Iv
Correction value T for correcting 8 according to the cooling water temperature Tw
The MTW is determined by referring to a map based on the detected value of the cooling water temperature Tw, and based on this correction value 'rMTW, the mask processing time T. is set for a long time.

Then, in step 6, the basic time 'I'l4vl+ is corrected {I1iT. ? , 1 to obtain the final mask processing time T. Calculate.

In step 7, start switch l9 is turned on and off.
is determined, and when the star 1 switch 19 is turned on, the process proceeds to step 8.

In step 8, after the start switch 19 is turned on, the mask processing time T. The reference angle signal REF from the crank angle sensor l4 is forcibly maintained at a high level until the time elapses, or the rising edge of the reference angle signal REF detected by comparison with the slice level is ignored. , detection of the rise of the reference angle signal REF is disabled within the mask processing time T8. Therefore, even if there is a change in the level of the reference angle signal REF around the slice level within the mask processing time 'F, 4, it is assumed that the change has not occurred.

That is, when the start switch 19 is turned on and the starter motor is driven while the reference angle signal REF is at a high level, the voltage 8 decreases as shown in FIG. A decrease in the level of REF is erroneously detected as a normal change in the reference angle signal REF, and in the case of this embodiment, fuel injection will be performed at an incorrect reference angle position. Therefore, the voltage Vll before starting
The time T. during which the voltage drop is predicted to occur is determined based on the temperature and cooling water temperature 'I''W, and various controls and calculations are not performed based on the detection of the reference angular position within this time T. Since the reference angular position is not erroneously detected due to voltage drop, fuel controllability at startup is ensured and pulsatility is improved.

In the routine shown in the flowchart of FIG. 4 above, the rising of the reference angle signal REF is disabled for a predetermined period of time after starting, but the predetermined period of time from starting is based on the number of rises rather than time management from starting. Processing may also be performed to disable the rising edge detection.

The second embodiment will be explained according to the routine shown in the flowchart of FIG.

Here, the processing in steps 11 to 13 is as follows:
Since the steps are the same as steps 1 to 3 in the flowchart of FIG. 4, the explanation will be omitted.

Therefore, when it is determined that the reference angle signal REF (detection pulse signal) is at a high level while the engine is stopped and the process proceeds to step 14, in step 14, detection of the rise of the reference angle signal REF is started based on the cooling water temperature Tw. Set the number of times C to cancel (invalidate) from the time.

Then, when it is detected in step 15 that the start switcher I9 has been turned on, it is determined in step 16 whether or not a rising edge of the reference angle signal R E l'' has been detected.

Here, if a rise is detected, the process proceeds to step 17 where the counter ant is incremented by 1, and in the next step 18 it is determined whether or not the raised counter cnt is equal to or less than the number of cancellations C set in step 14.

When the counter cnt is equal to or less than the number of cancellations C, the process advances to step 19 to cancel the current rise detection, assume that no rise has been detected, and return to step 16 again (see FIG. 7).

When the number of canceled rises exceeds the number of cancellations C, the process advances to step 20 and the counter cn
This routine is ended after resetting t to zero, and subsequent rise detection is used for engine control without any invalidation processing.

Therefore, even in the control example shown in the flowchart of FIG. 5, even if the electric voltage decreases due to the drive of the starter motor at the time of starting and a decrease in the level of the reference angle signal REF occurs, when this level decrease is restored, Since the rise detection in is disabled, it is possible to avoid erroneous control of fuel supply performed at the time of reference angular position detection.

In the examples shown in FIGS. 4 and 5 described above, processing is performed to invalidate the rise of the reference angle signal REF within a predetermined period from the time of startup, but as shown in the flowchart of FIG. 6, It is also possible to directly observe the voltage VB of the battery l7 and perform invalidation processing for detecting the rising edge of the reference angle signal REF.

In the routine shown in the flowchart of FIG. 6, when it is determined that the reference angle signal REF is at a high level when the engine l is stopped (step 3
3) Proceed to step 34 and set flag F to 1,
On the other hand, when the reference angle signal R is at a low level in the stopped state, the flag F is set to zero in step 35;
The level of the reference angle signal REF in the engine stopped state can be determined by the flag F.

Then, when the engine I rotates, the process proceeds from step 32 to step 36, where the flag F is determined. If the flag F is zero, this routine ends without disabling the rise detection, but if the flag F is 1, the rise of the detection pulse signal is erroneously detected due to a voltage drop due to driving the starter motor. Therefore, proceed to step 37.

In step 37, the voltage ■8 of the battery l7 and the predetermined voltage ■8 are compared (see FIG. 7), and Va<V++s
When this voltage decreases, the reference angle signal RE
Since there is a risk that the level of F may also be temporarily lowered and the reference angle position may be erroneously detected, the process proceeds to step 38 where the rising detection is masked and made invalid.

Therefore, according to this embodiment, when the voltage (2) drops due to driving the starter motor when starting the engine, the startup detection at that time will be treated as invalid, and the voltage drop will not occur due to driving the starter motor. However, fuel controllability during startup can be prevented from deteriorating.

In this embodiment, the fuel supply timing is controlled based on the detection of the rising edge of the reference angle signal REF, but it may be used for other engine controls such as ignition timing control.

<Effects of the Invention> As described above, the present invention provides a crank angle detection device in which a reference angular position is detected by comparing a detection pulse signal that rises at a predetermined reference angular position of the tarrank shaft with a predetermined slice level. When the level of the detection pulse signal is high when the engine is stopped,
Since the configuration is configured to disable the rise detection for a predetermined period after starting, various engine controls are performed based on the rise of the pulse when the level of the detection pulse signal changes due to the voltage drop caused by the starter motor drive at the time of start. This improves fuel supply controllability during startup.

In addition, by disabling detection of the rise of the detection pulse signal when the detection pulse signal is at a high level when the engine is stopped and the power supply voltage is below a predetermined value while the engine is rotating, the level change of the detection pulse signal can be predicted. This prevents erroneous detection of a rise in voltage when the voltage drops, and similarly improves engine controllability when starting the engine.

[Brief explanation of the drawing]

Figures 1 and 2 are block diagrams showing the configuration of the present invention, Figure 3 is a system schematic diagram showing an embodiment of the present invention, and Figures 4 to 6 are examples of crank angle detection control. FIG. 7 is a time chart showing the characteristics of the control contents shown in FIGS. 4 to 6, respectively.
FIG. 8 is a time chart showing an example of fuel supply control at startup, and FIG. 9 is a time chart for explaining problems in the conventional detection device. 1...4] Seki 12... Control unit 14...
...Crank angle sensor 17...Battery 18...
・Ignition switch 19...Starter switch

Claims (2)

[Claims] (1) A crank angle detection means that outputs a detection pulse signal that rises at each reference angle position of the crankshaft, and determines the rise of the detection pulse signal by comparing the detection pulse signal with a predetermined slice level, and a reference angular position detecting means for detecting an angular position; and a reference angular position detecting means for detecting a reference angular position for a predetermined period from engine start when the detection pulse signal output from the crank angle detecting means is at a high level when the engine is stopped. A crank angle detection device for an internal combustion engine, comprising: invalidation processing means for invalidating detection of an angular position for a predetermined period. (2) A crank angle detection means that outputs a detection pulse signal that rises at each reference angle position of the crankshaft, and compares the detection pulse signal with a predetermined slice level to determine the rise of the detection pulse signal and determines the rise of the detection pulse signal and a reference angular position detection means for detecting an angular position; a power supply voltage detection means for detecting a power supply voltage of the crank angle detection means; and a detection pulse signal outputted from the crank angle detection means at a high level when the engine is stopped. and voltage drop invalidation processing means for invalidating the detection of the reference angular position by the reference angular position detection means when the power supply voltage detected during engine rotation is below a predetermined value. A crank angle detection device for an internal combustion engine, characterized by: