TWI510706B - Control devices for internal combustion engines, power units for straddling vehicles, and straddle-type vehicles - Google Patents

Description

Control device for internal combustion engine, power unit of straddle type vehicle and straddle type vehicle

The present invention relates to a control device for an internal combustion engine, a power unit of a saddle riding vehicle, and a straddle type vehicle.

Patent Document 1 proposes a technique in which a sensor for covering an operational state of an internal combustion engine is covered with a cover in a motorcycle or an automatic three-wheeled motorcycle, and the sensor is protected from small stones or the like.

(prior technical literature) (Patent Literature)

Patent Document 1: Japanese Patent No. 3790770

At present, the inventors of the present invention have studied the application of controlling the knocking countermeasure control of the internal combustion engine while monitoring the occurrence of knocking of the internal combustion engine in the straddle type vehicle to avoid frequent occurrence of knocking.

As a configuration for monitoring the occurrence of knocking, it is possible to investigate a configuration in which a knock sensor for detecting vibration of an internal combustion engine is mounted on a vehicle, and The occurrence of knocking is determined at the output of the knock sensor.

However, in a straddle type vehicle, when driving on a bad road (that is, a road where the road surface is not good), an external condition such as a small stone colliding with an internal combustion engine or a crankcase may cause a knock sensor. The output has an impact. In the case where the small stone or the like collides, the output of the knock sensor is considered to be contaminated with foreign noise due to the impact, and it is difficult to correctly determine the occurrence of knocking.

Even if Xiaoshi does not directly collide with the knock sensor, if the part that transmits vibration to the knock sensor is collided by Xiaoshi or the like, the impact of collision of Xiaoshi or the like on the knock sensor may occur. Therefore, if only the configuration in which the knock sensor is covered by the cover is used as shown in Patent Document 1, the influence by the collision of Xiaoshi or the like does not disappear.

An object of the present invention is to provide a control device for an internal combustion engine, a power unit of a straddle type vehicle, and a straddle type vehicle in which a knocking feeling is caused even by a collision of a small stone or the like In the case where foreign noise is mixed in the output of the detector, the knocking can be satisfactorily handled.

A control device for an internal combustion engine according to an aspect of the present invention is a control device that detects a signal input from the knock sensor to the internal combustion engine, and the knock sensor detects vibration of an internal combustion engine mounted in a straddle type vehicle, and the control device of the internal combustion engine A configuration is provided in which the first obtaining means takes in a signal output from the knock sensor in a first period during which the knocking may occur during the one cycle of the internal combustion engine; Means of obtaining During a period of the foregoing internal combustion engine, a signal output from the knock sensor is taken in a second period, which is to remove the first period and remove noise caused by mechanical vibration of the internal combustion engine. At least a part of the period after the occurrence period; the first control means determines the occurrence of the knock based on the signal taken by the first obtaining means, and suppresses the knocking in the case where the knocking occurs Controlling the internal combustion engine; and the second control means determining the occurrence of the external noise caused by the external condition of the straddle type vehicle based on the signal taken by the second obtaining means, and based on the determination result The control content of the aforementioned internal combustion engine for the aforementioned first control means is changed.

A power unit of a straddle type vehicle according to an aspect of the present invention includes a built-in internal combustion engine mounted on a straddle type vehicle, a knock sensor that detects vibration of the internal combustion engine, and a control device for the internal combustion engine.

A straddle-type vehicle according to an aspect of the present invention is configured to include at least a part of an internal combustion engine disposed below a seat cushion surface, a knock sensor for detecting vibration of the internal combustion engine, and a control device for the internal combustion engine. .

According to the present invention, even when foreign noise is mixed in the output of the knock sensor due to collision of a small stone or the like, the knocking can be satisfactorily handled.

1‧‧‧Sitting vehicle

3‧‧‧ Front wheel

4‧‧‧ Rear wheel

5‧‧‧ engine unit

7‧‧‧ Seat cushion

10‧‧‧knock sensor

20‧‧‧ ECU (Engine Control Unit)

21‧‧‧knock feature extraction circuit

211‧‧‧Gain Adjustment Department

212‧‧‧Filter Processing Department

213‧‧Rectification Processing Department

214‧‧‧ Peak Maintenance Processing Department

22‧‧‧Interface circuit

23‧‧‧Microcomputer

231‧‧‧knock determination value calculation unit

232‧‧‧Detonation Judgment Department

233‧‧‧ Bad Road Noise Judgment Department

234‧‧‧Ignition Period Computing Department

235‧‧‧Fuel injection calculation department

236‧‧‧Actuator Control Unit

237‧‧"Window Control Department

30‧‧‧fuel injection unit

40‧‧‧Ignition unit

50‧‧‧EGR valve (exhaust gas recirculation valve)

51‧‧‧ Engine

52‧‧‧Power Transmission Department

53‧‧‧Sensor cover

60‧‧‧Crank angle sensor

Fig. 1 is an external view showing a straddle type vehicle according to an embodiment of the present invention.

Fig. 2 is a block diagram showing an engine control unit of a straddle type vehicle according to an embodiment of the present invention and its peripheral configuration.

Fig. 3 is a block diagram showing an example of a knocking feature extraction circuit of Fig. 2;

Fig. 4 is a flow chart showing the knock determination processing executed by the engine control unit.

Fig. 5 is a view for explaining knocking determination processing.

Fig. 6 is a flowchart showing the knocking countermeasure control process executed by the engine control unit.

Fig. 7 is a table showing the calculation condition of the arithmetic processing of step S66 of Fig. 6.

Fig. 8 is a timing chart for explaining an example of knocking countermeasure control processing.

Fig. 9 is a view for explaining a detection window in which a detection window indicates a signal extraction period of the knock feature extraction circuit.

Fig. 10 is a flowchart showing the first bad road noise determination processing executed by the engine control unit.

Fig. 11 is a flowchart showing a variation of the first bad road noise determination processing.

Fig. 12 is a flow chart showing the second bad road noise determination processing executed by the engine control unit.

Fig. 13 is a table showing the determination condition of the final bad road noise determination processing executed by the engine control unit.

Fig. 14 is a view for explaining a variation of the detection window, wherein the detection window indicates the signal extraction period of the knock feature extraction circuit.

Fig. 15 is a flowchart showing the bad road noise countermeasure control processing executed by the engine control unit.

Fig. 16 is a timing chart showing an example of the bad road noise countermeasure control processing.

Fig. 17 is a flowchart showing a first modification of the bad road noise countermeasure control processing.

Fig. 18 is a flowchart showing a second modification of the bad road noise countermeasure control processing.

Fig. 19 is a table showing the calculation condition of the knocking countermeasure control process of the second embodiment.

Fig. 20 is a flowchart showing the bad road noise countermeasure control processing of the second embodiment.

Fig. 21 is a table showing the calculation condition of the knocking countermeasure control processing of the third embodiment.

Fig. 22 is a flowchart showing the bad road noise countermeasure control processing of the third embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Implementation type 1)

Fig. 1 is an external view showing a straddle type vehicle according to an embodiment 1 of the present invention. Fig. 2 is a block diagram showing an ECU (engine control unit) according to an embodiment of the present invention and its peripheral configuration.

The straddle type vehicle 1 of the present embodiment is a vehicle on which a driver rides across a seat cushion, and is, for example, a motorcycle. As shown in Figure 1, straddle type The vehicle 1 includes a front wheel 3, a rear wheel 4, an internal combustion engine, that is, an engine 51, a power transmission unit 52, an engine control unit (ECU, equivalent to an internal combustion engine control device) 20, a handlebar 6, and a ride. The seat cushion 7 on which the person is seated, the knock sensor 10, and the like. Further, as shown in Fig. 2, the straddle type vehicle 1 has a crank angle sensor 60, an ignition unit 40, a fuel injection unit 30, and an exhaust gas recirculation (Exhaust Gas Recirculation, EGR) valve 50.

The power unit according to the embodiment of the present invention is a unit that unitizes a power source that is a power source of the straddle type vehicle 1, and includes an engine 51 and an ECU 20 among the components of the straddle type vehicle 1. The power unit may include a power transmission portion 52, a generator, or both.

The engine 51 is a single cylinder engine with a single cylinder and is an air cooled engine. The engine 51 is a 4-stroke engine that sequentially repeats an intake stroke (also referred to as a stroke), a compression stroke, a combustion stroke, and an exhaust stroke. The engine 51 has a cylinder head, a cylinder block, a piston, a connecting rod, a crankshaft, and the like. The cylinder head of the engine 51 is provided with an intake valve, an exhaust valve, and a spark plug.

Within the cylinder of the cylinder block, the piston is configured to reciprocate and the piston is coupled to the crankshaft via a connecting rod. The intake valve is opened and closed during the intake stroke, and a mixed gas of air and fuel is taken into the cylinder. The exhaust valve is opened and closed during the exhaust stroke, and the combustion gas is exhausted. When the intake valve is closed and the exhaust valve is closed, a mechanical vibration called seating noise occurs. The mixed gas is combusted in the cylinder by the ignition of the spark plug, whereby the piston reciprocates and the crankshaft is rotationally driven. During the expansion of the combustion of the mixed gas in the cylinder, there is sometimes an abnormality in the ignition of the mixed gas near the cylinder wall. Happening. The vibration caused by this abnormal fire is knocking.

The engine 51 is disposed between the front wheel 3 and the rear wheel 4, and at least a portion thereof is disposed below the seat surface of the seat cushion 7. At least a part of the front portion and the lower portion of the engine 51 is configured to be exposed to the outside, and is configured to directly contact the outside air during running.

The power transmission portion 52 has a transmission, a drive shaft, and a crankcase that houses these components and the crankshaft. The rotational force of the crankshaft is transmitted to the drive shaft via the transmission, and is transmitted from the drive shaft to the rear wheel 4 via a chain or the like.

The cylinder block of the engine 51 and the crankcase of the power transmission portion 52 are integrally connected, and constitute an engine unit 5 in which the transmission engine 51 and the power transmission portion 52 are integrated. These components also exist without being integrated.

The ECU 20 is a control device that mainly performs control related to combustion of the engine 51. The ECU 20 executes a knocking determination process for determining whether or not knocking has occurred in the engine 51, and a knocking countermeasure control process for realizing efficient combustion of the engine 51 in a range in which knocking occurs infrequently, and details will be described later. Further, the ECU 20 executes a process of determining the occurrence of the bad channel noise and the bad channel noise countermeasure control process, wherein the bad channel noise countermeasure control process is to change the knock countermeasure control process when the bad road noise occurs. Control content.

The ignition unit 40 (Fig. 2) includes a spark plug disposed on the cylinder head and ignites the spark plug based on the control signal of the ECU 20.

The fuel injection unit 30 (Fig. 2) includes a throttle valve that controls the amount of intake air, and a fuel injection device that supplies fuel to the intake passage. The fuel injection unit 30 injects fuel to the intake passage at a timing and amount based on the control signal of the ECU 20. When the inhalation valve is open, it is supplied to the inspiratory passage A mixed gas composed of gas and fuel is supplied into the cylinder of the engine 51.

The EGR valve 50 (second drawing) is a valve that recirculates a part of the combustion gas discharged from the cylinder of the engine 51 to the exhaust passage to the intake passage, and changes the opening degree based on the control signal of the ECU 20. Further, the control of the EGR valve 50 and the EGR valve 50 may be omitted.

The crank angle sensor 60 (second drawing) is a sensor that detects the rotation angle of the crankshaft of the engine 51, and outputs a crank angle signal to the ECU 20. The ECU 20 can count the rotation angle of the crankshaft and the engine rotation speed based on the crank angle signal.

The knock sensor 10 (Fig. 2) is a vibration detecting sensor for detecting the occurrence of knocking and detecting the vibration occurring in the engine 51. The knock sensor 10 has, for example, a piezoelectric element that applies a vibration acceleration generated in the engine 51, and the knock sensor 10 outputs an AC voltage corresponding to the vibration acceleration from the piezoelectric element as a detection signal. The knock sensor 10 is, for example, a non-resonant type sensor in which the gain becomes flat in the frequency range in which the object is detected. The knock sensor 10 is mounted, for example, to the cylinder block of the engine 51 and is covered by the sensor cover 53. The detection signal of the knock sensor 10 is input to the ECU 20.

<Details of ECU 20>

Next, a detailed configuration of the ECU 20 will be described.

As shown in FIG. 2, the ECU 20 has a knocking feature extraction circuit 21, a interface circuit 22, and a microcomputer 23. The microcomputer 23 includes a knock determination value calculation unit 231, a knock determination unit 232, a bad path noise determination unit 233, an ignition timing calculation unit 234, a fuel injection calculation unit 235, an actuator control unit 236, and a window control unit. 237.

Among the above-described components, the knock determination value calculation unit 231, the knock determination unit 232, and the ignition timing calculation unit 234 correspond to the first control means for suppressing the occurrence of knocking and suppressing knocking. The way to control the engine 51. The bad road noise determination unit 233 and the ignition timing calculation unit 234 also function as the second control means, and the second control means determines that the bad path noise is generated, and changes the control content of the engine 51 based on the occurrence of the bad path noise.

Each part of the microcomputer 23 may be constituted by a software executed by a CPU (Central Processing Unit) or may be constituted by a hardware such as a DSP (Digital Signal Processing Circuit).

The knocking feature extraction circuit 21 is a circuit for extracting the following signal components: a signal component from the knock sensor 10 and used to determine the knocking signal component; and a signal component for determining the bad road noise. The bad road noise has a frequency close to knocking. The knocking feature extraction circuit 21 extracts the signal component during the specified signal extraction period, wherein the signal extraction period is specified according to the time point signal from the window control unit 237; the knock feature extraction circuit 21 explodes the extracted signal component The earthquake determination value calculation unit 231, the knock determination unit 232, and the bad road noise determination unit 233 output. For details on the signal extraction period.

FIG. 3 is a block diagram showing an example of the knock feature extraction circuit 21.

As shown in FIG. 3, the knock feature extraction circuit 21 is mainly composed of a gain adjustment unit 211, a filter processing unit 212, a rectification processing unit 213, and a peak hold processing unit 214.

The gain adjustment unit 211 adjusts the increase of the detection signal of the knock sensor 10 beneficial. The adjustment of the gain is performed, for example, for the adjustment of the level of the detection signal that changes according to the engine speed, or the adjustment of the level of the detection signal that changes based on the individual difference of the knock sensor 10.

The filter processing unit 212 has, for example, a band pass filter circuit that allows a large number of frequency components including knock vibration to pass from the detection signal more than other frequency components.

The rectification processing unit 213 rectifies the detection signal of the alternating current waveform.

The peak hold processing unit 214 holds and outputs the peak voltage of the detection signal in the signal extraction period specified by the timing signal of the window control unit 237.

The specific configuration of the knocking feature extraction circuit 21 is not limited to the example of FIG. 3, as long as it is possible to extract a signal component that is contained in a large amount of knocking vibration from the detection signal of the knock sensor 10 during the specified signal extraction period. It can be composed.

The interface circuit 22 (Fig. 2) adjusts the waveform of the output signal of the crank angle sensor 60 and outputs it to the microcomputer 23.

The window control unit 237 receives the crank angle signal from the crank angle sensor 60 and controls the processing timing of each portion. Specifically, the window control unit 237 outputs a timing signal indicating the signal extraction period to the knock feature extraction circuit 21. Further, the window control unit 237 outputs the timing signal of the take-in signal to the knock determination value calculation unit 231, the knock determination unit 232, and the bad road noise determination unit 233. Details about these timings are given later.

The knock determination value calculation unit 231 and the knock determination unit 232 execute a knock determination process to be described later and determine the knock occurrence. The knock determination unit 232 will The determination result is notified to the ignition timing calculation unit 234, the fuel injection calculation unit 235, and the actuator control unit 236.

The ignition timing calculation unit 234 executes the knocking countermeasure control processing and the bad road noise countermeasure control processing which will be described later, and controls the ignition unit 40.

The fuel injection calculation unit 235 executes the knocking countermeasure control processing and the rough road noise countermeasure control processing described in the second embodiment, and controls the fuel injection unit 30. Regarding the first embodiment, the fuel injection calculation unit 235 may be omitted.

The actuator control unit 236 executes the knocking countermeasure control processing and the rough road noise countermeasure control processing described in the third embodiment, and controls the EGR valve 50. Regarding the first embodiment, the actuator control unit 236 may be omitted.

The bad road noise determination unit 233 executes a bad path noise determination process to be described later, and determines that the bad path noise is generated. The bad road noise determination unit 233 notifies the ignition timing calculation unit 234, the fuel injection calculation unit 235, and the actuator control unit 236 of the determination result.

<knocking determination processing>

Next, the knock determination processing executed by the knock determination value calculation unit 231 and the knock determination unit 232 will be described.

Fig. 4 is a flow chart showing the knock determination processing.

The knock determination processing of FIG. 4 starts at a predetermined timing within one cycle of the engine 51, and is repeatedly executed in each cycle of the engine 51.

When the knock determination processing is started, first, in step S41, the knock determination value calculation unit 231 and the knock determination unit 232 use the output level of the knock feature extraction circuit 21 as a burst based on the timing signal of the window control unit 237. The vibration vibration detection value is obtained. Specifically, the microcomputer 23 extracts the knock feature The output voltage of the path 21 is A/D (analog/digital) converted, and the converted digital value is obtained. The timing at which the knocking vibration detection value is obtained is a timing at which the period of the knocking vibration (the detection window KW of FIG. 9) has just occurred during one cycle of the engine 51. The knock vibration detection value is a signal value extracted by the knock feature extraction circuit 21 during this period.

In step S42, the knock determination value calculation unit 231 and the knock determination unit 232 logarithmically convert the acquired knock vibration detection values to calculate a logarithmic knock vibration detection value.

In step S43, the knock determination unit 232 compares the logarithmic knock vibration detection value with the knock determination threshold (=threshold value offset + log average value) to determine whether the logarithmic knock vibration detection value is greater than the knock determination. Threshold value. The process of step S43 is an example of a process of determining the occurrence of knock. The logarithmic average value is a value calculated by the knock determination value calculation unit 231 in step S46. The threshold offset is a value determined in advance by experiments or the like.

When the result of the comparison is that the logarithmic knock vibration detection value is larger than the knock determination threshold value, the knock determination unit 232 holds the determination result of "the occurrence of knock occurrence" in the memory or the like (step S44). The determination result held by the knock determination unit 232 is output to the ignition timing calculation unit 234, the fuel injection calculation unit 235, and the actuator control unit 236.

On the other hand, if the logarithmic knock vibration detection value is smaller than the knock determination threshold value, the knock determination unit 232 holds the determination result of "no knock occurrence" in the memory or the like (step S45). The determination result held by the knock determination unit 232 is output to the ignition timing calculation unit 234, the fuel injection calculation unit 235, and the actuator control unit 236.

If it is assumed that the control process in step S43 is followed by the control process corresponding to the occurrence of knocking, the processes of steps S44 and S45 can be omitted.

In step S46, the knock determination value calculation unit 231 calculates an average value of the plurality of knock vibration detection values acquired in the past plurality of engine cycles, and calculates a logarithmic mean value obtained by logarithmically converting the average value. . Then, the knock determination processing of one time is ended.

Fig. 5 is a view for explaining knocking determination processing. The horizontal axis of Fig. 5 represents the logarithmic knock vibration detection value, and the vertical axis represents the frequency in the engine cycle in the past plural times.

As described above, the knock vibration detection value is a signal value extracted from the detection signal of the knock sensor 10 during a period in which knocking is likely to occur. Therefore, when the logarithmic knock vibration detection value is acquired and calculated across a plurality of engine cycles, as shown in the bar graph of FIG. 5, the logarithmic knock vibration detection value is distributed in a low range. In addition, when knocking occurs at a lower frequency, the logarithmic knock vibration detection value and distribution become higher values.

On the other hand, the tendency of the distribution of the logarithmic knock vibration detection value does not change much, but the absolute value of the range of the logarithmic knock vibration detection value distribution may occur depending on external factors such as the engine rotation speed or the individual deviation of the knock sensor 10 Variety.

Therefore, in the knock determination processing of FIG. 4, the logarithmic mean value is calculated from the parent (population) of the knocking vibration detection value acquired across the plurality of engine cycles (step S46), on the logarithmic average value. The knock determination threshold value is determined in addition to the threshold offset (step S43). and, In the knock determination processing of FIG. 4, it is possible to determine the knock vibration detection value whose value is larger than the normal distribution due to the knock by comparing the magnitude of the knock determination threshold and the log knock vibration detection value (step S43). Further, it is possible to determine the occurrence of knocking.

According to the above-described knock determination processing, when abnormal noise such as bad road noise does not occur, it is possible to accurately determine the occurrence of knocking.

<knocking countermeasure control processing>

Next, the knocking countermeasure control process executed by the ignition timing calculating unit 234 will be described.

Fig. 6 is a flowchart showing the knocking countermeasure control process. Fig. 7 is a table showing the calculation condition of the calculation processing of step S66 of Fig. 6. Fig. 8 is a timing chart for explaining an example of knocking countermeasure control processing.

The knock countermeasure control process starts at a predetermined timing within one cycle of the engine 51, and is repeatedly executed in each cycle of the engine 51.

As shown in FIG. 8, the knocking countermeasure control process is a process of correcting the ignition timing based on the reference ignition timing based on the determination of the knocking occurrence.

Specifically, as shown in Fig. 8, if the occurrence of knocking has been determined, the ignition timing is delayed by only a certain amount (hereinafter referred to as "the amount of hysteresis at the time of knocking determination"). In addition, if the period in which the occurrence of knocking is not determined is continued for a predetermined period (hereinafter referred to as "recovery period C"), the amount of advancement smaller than the amount of hysteresis at the time of knock determination (hereinafter referred to as "pre-recovery amount at recovery" is used. ) Advance the ignition period.

The reference ignition timing refers to an ignition timing based on a reference determined by the number of revolutions of the engine 51 or the like.

When the knocking countermeasure control process of FIG. 6 is started, the ignition timing calculating unit 234 first determines in step S61 whether or not the cycle counter that counts the engine cycle is the reset cycle C (end cycle of the period C of FIG. 8).

If the result of the determination is affirmative, the ignition timing calculation unit 234 holds the determination result of the restoration timing in the memory or the like in step S62.

Next, the ignition timing calculation unit 234 resets the cycle counter to zero in step S64.

On the other hand, if the result of the determination in step S61 is negative, the ignition timing calculation unit 234 holds the determination result of "not the recovery timing" in the memory or the like in step S63.

If it is assumed that the control processing corresponding to the determination result is immediately after the determination processing of step S61, the processing of steps S62 and S63 can be omitted.

Next, the ignition timing calculation unit 234 increments the cycle counter in step S65.

In step S66, the ignition timing calculation unit 234 calculates the ignition timing correction value in accordance with the calculation condition table 70 (see Fig. 7). The calculation condition is determined based on the following items in Fig. 4: the knock determination result held in the memory or the like in the knock determination processing, and the memory or the like held in the step S62 or the step S63 in Fig. 6 The result of the determination of "whether it is a recovery timing".

In other words, as shown in the column (1) of Fig. 7, if it is the restoration timing and the determination of the occurrence of knocking, the ignition timing calculation unit 234 calculates the ignition timing correction value "the correction value before one cycle - the explosion The amount of hysteresis in the earthquake determination + the amount of advancement in recovery." Through this calculation, in the period determined to have knocking, The ignition timing lag "lag amount at the time of knock determination - advance amount at the time of recovery" (refer to the period C1 of Fig. 8), and it is possible to prevent frequent occurrence of knocking.

As shown in the column (2) of Fig. 7, if it is the restoration timing and the determination of the occurrence of knocking, the ignition timing calculation unit 234 calculates the ignition timing correction value "correction value before one cycle + advancement amount at recovery time" ". By this calculation, the ignition timing is gradually advanced in the period in which the knocking has not occurred for a long time (cycles C2, C3, C4, and C5 in Fig. 8), and the combustion of the engine 51 can be performed more efficiently.

As shown in the column (3) of Fig. 7, the ignition timing calculation unit 234 calculates the ignition timing correction value "the correction value before one cycle - the hysteresis amount at the time of knock determination", if it is not the recovery timing and the determination that knocking occurs. ". According to this calculation, if it is determined that knocking has occurred, the ignition timing is delayed by only "the amount of hysteresis at the time of knocking determination", and the occurrence of knocking can be prevented from occurring frequently (refer to the period N1 of Fig. 8).

As shown in the column (4) of Fig. 7, if it is not the restoration timing and the determination of the occurrence of knocking, the ignition timing calculation unit 234 sets the ignition timing correction value to the same value as the correction value before one cycle. Without changing the ignition timing correction value.

When the ignition timing correction value is calculated, the ignition timing calculation unit 234 outputs the timing signal to the ignition unit 40 at the timing obtained by reflecting the correction value, and ignites the spark plug.

In the calculation processing (step S66) of the ignition timing correction value in Fig. 6, in order to prevent the ignition timing from exceeding an appropriate range, the maximum value and the minimum value of the ignition timing correction amount may be determined in advance. And can be done in the following manner Control: The ignition timing correction amount is set to the maximum value when the ignition timing correction amount exceeds the maximum value, and the ignition timing correction amount is set to the minimum value when the ignition timing correction amount is lower than the minimum value.

According to the above-described knock determination processing (Fig. 4) and the knocking countermeasure control processing (Fig. 6), as shown in Fig. 8, when it is determined that knocking has occurred, the ignition timing is delayed by delay. It can prevent frequent knocking afterwards. Further, in the case where it is not determined that knocking has occurred, the ignition timing is gradually advanced. Through these controls, the ignition timing is controlled near the knock limit, and the fuel economy and output characteristics of the engine 51 are improved.

<Bad road noise and detection window>

Next, a description will be given of a bad path noise that may be mixed into the knock sensor 10 and a detection window for signal extraction by the knock feature extraction circuit 21 (Fig. 2).

In the case where the straddle type vehicle 1 travels on a bad road such as a gravel road, the bouncing stones may collide with the crankcase of the engine 51 or the power transmission portion 52, and the vibration is transmitted to the knock sensor 10 to become an external miscellaneous The signal (referred to as "bad noise") is mixed into the detection output of the knock sensor 10. When the bad-path noise has a component close to the frequency of the knocking vibration, the knock determination value calculation unit 231 and the knock determination unit 232 may fail to accurately determine the knocking occurrence.

For example, when the strength of the bad road noise is high, the knock determination value calculation unit 231 and the knock determination unit 232 may erroneously determine that the bad road noise is knocking.

In addition, in the case where a large number of bad road noises are mixed in, A large error occurs in the distribution of the logarithmic knock vibration extraction value in FIG. 5, and a large error is also included in the knock determination threshold (Fig. 5) calculated by the knock determination value calculation unit 231. When the knock determination threshold value is set to be larger than the normal value, it is difficult for the knock determination value calculation unit 231 and the knock determination unit 232 to determine that knocking is performed when a relatively small knock occurs.

Fig. 9 is a view for explaining a detection window showing a signal extraction period of the knock feature extraction circuit. FIG. 9 shows an example of the detection signal waveform of the knock sensor 10 in one cycle period (-360° to 360°) of the engine 51. The horizontal axis of the waveform diagram of Fig. 9 indicates the crank angle at which the top dead center is 0, and the vertical axis indicates the signal strength of the detection signal. The top dead center is the top dead center on the compression when the piston compresses the mixed gas in the cylinder to the limit.

In the present embodiment, the bad road noise is determined together with the vibration signal of the knocking, and therefore the knocking feature extraction circuit 21 (Fig. 2) performs signals in the detection windows KW, NW1, and NW2 shown in Fig. 9. Extraction. The window control unit 237 (Fig. 2) outputs the timing signals for performing the peak hold processing by the peak hold processing unit 214 in conjunction with the detection windows KW, NW1, and NW2.

The detection window KW corresponds to a first period in which knocking may occur. For example, the detection window KW is set to a period from the start to the top dead center to the end of the combustion diffusion in the cylinder of 60° ± 5°.

The detection window NW1 corresponds to the second period, which does not overlap with the detection windows KW, NW2, and the vibration of the engine 51 is less than that during the occurrence of the mechanical vibration of the engine 51. For example, the detection window NW1 is set to a period in which the vibration in the exhaust stroke is less likely to occur. For example, the detection window NW1 can be set to a period other than the seating period of the exhaust valve in the exhaust stroke.

The detection window NW2 corresponds to a third period in which the engine 51 is mechanically vibrated. For example, the detection window NW2 is set to a period during which the seating noise of the discharge valve occurs.

As described above, the signal extracted by the detection window KW is taken in by the earthquake determination value calculation unit 231 and the knock determination unit 232 (second diagram) to determine the occurrence of knocking. The knock determination value calculation unit 231 and the knock determination unit 232 perform the acquisition of the signal by the timing signal of the window control unit 237.

On the other hand, the signals extracted by the detection windows NW1 and NW2 are taken in by the bad path noise determination unit 233 to determine the occurrence of bad path noise. The bad road noise determination unit 233 performs the acquisition of the signal by the timing signal of the window control unit 237. The bad road noise determination unit 233 executes the two types of bad path noise determination processing described below based on the acquired signal.

Among the knocking feature extraction circuit 21, the window control unit 237, the knock determination value calculation unit 231, and the knock determination unit 232, the configuration of the signal for taking in the detection window KW corresponds to the first acquisition means. Among the knocking feature extraction circuit 21, the window control unit 237, and the bad channel noise determination unit 233, the signal of the detection window NW1 is equivalent to the second acquisition means, and the signal of the detection window NW2 is equivalent to the configuration. The third means of acquisition.

<First bad road noise determination processing>

Fig. 10 is a flow chart showing the first bad road noise determination processing.

The first bad road noise determination process starts at a predetermined timing within one cycle of the engine 51, and is repeatedly executed in each cycle of the engine 51.

When the first bad road noise determination processing is started, the bad road noise determination unit 233 performs the signal level extracted by the detection window NW1 in step S101 ( The intrusion is referred to as "bad noise detection value". Specifically, the microcomputer 23 A/D converts the output voltage of the knock feature extraction circuit 21 at the designated timing to obtain the converted digital value.

In step S102, the bad path noise determination unit 233 determines whether or not the obtained bad path noise detection value is larger than the bad path noise threshold. The process of step S102 is an example of a process of determining whether or not the bad-path noise is generated as a foreign noise. The bad road noise threshold is a value calculated in step S106.

If the result of the determination is affirmative, the bad path noise determination unit 233 holds the determination result of the occurrence of the bad path noise state (1) in the memory or the like in step S103. Here, the bad channel noise state (1) represents that bad channel noise occurs at a small frequency. The reason for this will be described later.

On the other hand, if the result of the determination is "NO", the bad path noise determination unit 233 holds the determination result of "the bad channel noise state (1) does not occur" in the memory or the like in step S104.

In step S105, the bad channel noise determination unit 233 calculates the average value of the bad path noise detection values by using the plurality of bad channel noise detection values acquired in the past plurality of cycles as the parent.

In step S106, the bad channel noise determination unit 233 calculates the critical value of the occurrence of the bad path noise state (hereinafter referred to as the bad path noise threshold) using the average value of the bad path noise detection values. For example, the bad road noise determination unit 233 calculates "the average value of the bad path noise detection value × the coefficient determined by the experiment or the like in advance" as the bad path noise threshold value.

As described above, the bad channel noise detection value is a signal value extracted in a period in which the vibration in the engine cycle is small (the period in which the detection window NW1 is detected). because On the other hand, in the case where bad noise is generated at a small frequency, when the bad channel noise detection value is obtained across a plurality of engine cycles, the bad channel noise detection value is distributed in the low level range. At this time, when bad channel noise occurs, the bad channel noise detection value and distribution become a relatively high value.

On the other hand, the distribution of the bad road noise detection value does not change about the tendency of the distribution, but the absolute value of the distribution range changes depending on external factors such as the engine speed or the individual deviation of the knock sensor 10.

Therefore, in the bad-path noise determination processing of FIG. 10, the average value is calculated based on the parent of the bad-path noise detection value acquired across the plurality of engine cycles (step S105), and the average value is multiplied by the coefficient. Bad road noise threshold (step S106). Further, it is possible to determine the occurrence of bad-path noise in a situation where bad-path noise occurs at a low frequency by comparing the bad-channel noise detection value with the bad-path noise threshold.

The processing of steps S102, S105, and S106 functions as a statistical processing means for determining the degree of dispersion of the bad channel noise detection value.

Fig. 11 is a flowchart showing a variation of the first bad road noise determination processing.

The first bad road noise determination processing of Fig. 10 can be changed as shown in Fig. 11. That is, the comparison result of the bad road noise detection value and the bad road noise threshold value in FIG. 10 is the same as the comparison between the standard deviation of the bad road noise detection value in the parent and the predetermined critical value. Therefore, as shown in Fig. 11, the bad channel noise determination unit 233 calculates the standard deviation of the acquired bad channel noise detection values (step S112), and compares the calculated values with the bad roads determined in advance by experiments or the like. The threshold is set (step S113). Thus, the bad road noise determination unit In the same manner as the processing of FIG. 10, in the case where the bad-path noise occurs at a small frequency, it is possible to determine the presence or absence of the bad-path noise. The processing of steps S111, S114, and S115 is the same as the processing of steps S101, S103, and S104 of FIG.

The process of step S112 functions as a statistical processing means for calculating the degree of dispersion of the bad channel noise detection value.

As described above, the first bad road noise determination process can accurately determine the occurrence of bad path noise in a situation where bad path noise occurs at a small frequency. On the other hand, in the first bad-path noise determination process, when the bad-path noise occurs frequently, the parent of the bad-path noise detection value contains a large amount of bad-channel noise, so it is difficult to correct Determine the bad road noise. For example, in the case where the bad road noise is gradually increased, in the case where the bad road noise is gradually increased, or in the case where these conditions are combined, it is difficult to correctly determine in the first bad road noise determination processing. Bad road noise occurred.

Then, the bad road noise determination unit 233 executes the second bad road noise determination processing described next together with the first bad road noise determination processing.

<Second bad road noise determination processing>

Fig. 12 is a flowchart showing the second bad road noise determination processing.

The second bad road noise determination processing starts at a predetermined timing within one cycle of the engine 51, and is repeatedly executed in each cycle of the engine 51.

When the second bad road noise determination processing is started, the bad road noise determination unit 233 performs the signal level extracted by the detection window NW2 (Fig. 9) in step S121 (hereinafter referred to as "mechanical vibration noise detection value". Take in. The microcomputer 23 feeds the output voltage of the knock feature extraction circuit 21 at the specified timing. Line A/D conversion, and obtain the converted digit value.

In step S122, the bad path noise determination unit 233 calculates an average value (corresponding to the second statistical value) which is a mechanical vibration noise that is acquired in a plurality of cycles in the past. The detected value is used as the parent.

In step S123, the bad path noise determination unit 233 acquires the bad path noise detection value extracted in the detection window NW1. The process of acquiring the material can be the same as the process of step S101 of Fig. 10.

In step S124, the bad path noise determination unit 233 calculates an average value (corresponding to the first statistical value) which is a bad path noise that will be acquired in a plurality of cycles in the past. The detected value is used as the parent.

In step S125, the bad road noise determination unit 233 weights the average value of the bad path noise detection value and the average value of the mechanical vibration noise detection value by a predetermined coefficient, and then compares them. The process of step S125 is an example of a process of determining occurrence of bad path noise. The coefficient is a value determined in advance by experiments or the like in such a manner that the bad path noise can be appropriately determined.

The processing of steps S122 and S124 functions as a statistical processing means for calculating statistical information.

If the result of the comparison is that the "average value of the bad channel noise detection value x coefficient" is large, the bad channel noise determination unit 233 stores the determination result of "the occurrence of the bad channel noise state (2)" in step S126. Memory, etc. The so-called bad road noise state (2) means a state in which bad noise is generated at a high frequency.

On the other hand, if the "average value of the bad channel noise detection value x coefficient" is large, the bad channel noise determination unit 233 sets "bad noise" in step S127. The result of the determination that the state (2) does not occur is stored in the memory or the like.

And, the second bad road noise determination processing ends.

In the case where the bad road noise frequently occurs, the signal value of the detection window NW1 which is usually less vibrating generally includes a large number of signal values having a large number of bad road noises, and the average value of the signal values of the detection window NW1 becomes large. On the other hand, the signal value extracted during the detection window NW2 of the mechanical noise every time occupies a large component of mechanical noise, so the average value is compared with the average value in the case where no bad path noise occurs. The change is not big.

Therefore, in the second bad road noise determination processing, it is possible to perform the determination in the case where the bad road noise frequently occurs by comparing these average values.

<Final bad road noise determination processing>

Next, the final bad road noise determination processing executed by the bad path noise determination unit 233 will be described.

Fig. 13 is a table showing the determination condition of the final bad road noise determination processing.

The final bad road noise determination processing is executed by the bad road noise determination unit 233 in each cycle of the engine 51, for example.

The bad road noise determination unit 233 determines the occurrence of the final bad path noise by the determination condition table of FIG. 13 based on the determination result of the first bad road noise determination process and the determination result of the second bad road noise determination process. Yes or no.

In other words, when at least one of the determination result of the first bad road noise determination process and the determination result of the second bad road noise determination process is such a determination result, it is determined that a bad road has occurred. The noise came as the final judgment.

The bad road noise determination unit 233 holds the final determination result and notifies the ignition timing calculation unit 234 and the like.

<Example of change of detection window>

Here, a variation of the detection window for the determination of the bad road noise will be described.

Fig. 14 is a view for explaining an example of a change of the detection window during the signal extraction period of the knock feature extraction circuit.

The signal for determining the bad road noise is not limited to the above-described detection windows NW1 and NW2, and the condition for generating the vibration can be set for other periods similar to those of the detection windows.

If there are a plurality of periods in which the vibration is reduced in normal times, as shown in Fig. 14, a plurality of detection windows NW1 and NW3 can be set in a plurality of periods. The detection window NW3 corresponds to a period in the inhalation stroke.

In this case, the first bad road noise determination processing can be performed using the bad road noise detection values acquired by both of the detection windows NW1 and NW3. Further, independent first bad path noise determination processing can be performed based on each of the bad channel noise detection values acquired in the respective detection windows NW1, NW3.

Similarly, if there are a plurality of periods in which the mechanical vibration of the engine 51 is constantly generated, as shown in Fig. 14, a plurality of detection windows NW2, NW4 can be set in a plurality of periods. The detection window NW4 corresponds to the period during which the sitting noise of the intake valve occurs.

In this case, the second bad-path noise determination processing can be performed using the mechanical vibration noise detection values acquired by both of the detection windows NW2 and NW4. And, according to each of the detection windows NW2, NW4 The mechanical vibration noise detection value is subjected to an independent second bad road noise determination process. If a part of the previous period or a part of the following period is a period in which only a small vibration occurs, the detection windows KW, NW1, NW2, NW3, and NW4 may be expanded to include a period during which a part of the vibration is generated. The period in which only small vibration occurs is a period in which only vibration smaller than mechanical vibration and knocking vibration occurs. Further, if the detection windows KW, NW1, NW2, NW3, and NW4 are periods in which only a part of the small vibration occurs, the periods of this portion may overlap each other.

<Bad road noise countermeasure control processing>

Next, the bad road noise countermeasure control processing executed by the ignition timing calculation unit 234 will be described.

Figure 15 is a flow chart of the bad road noise countermeasure control process. Fig. 16 is a timing chart showing an example of the bad road noise countermeasure control processing. Fig. 16 is a view showing an example of a control operation of switching the ignition timing of the knocking countermeasure control processing by the bad road noise countermeasure control processing.

The bad road noise countermeasure control process starts, for example, at a predetermined timing within one cycle of the engine 51, and is repeatedly executed in each cycle of the engine 51. The ignition timing calculation unit 234 executes the bad road noise countermeasure control processing in parallel with the knock countermeasure control processing.

When the bad road noise countermeasure control processing is started, the ignition timing calculation unit 234 determines in step S151 whether or not the final determination result notified by the bad path noise determination unit 233 is "occurring".

When the determination result is "occurring", the ignition timing calculation unit 234 changes the restoration period to the long period when the bad path noise occurs in step S152. D. The recovery period is a period when the ignition timing is gradually advanced as explained in FIGS. 6 and 7.

As shown in Fig. 16, when the recovery period D is changed, the advancement speed of the ignition timing based on the determination that the knock does not occur in the knocking countermeasure control processing becomes slow.

Next, the ignition timing calculation unit 234 resets the timer T in step S154, and advances the processing to step S156.

On the other hand, if the result of the determination in step S151 is "no occurrence", the ignition timing calculation unit 234 determines in step S153 whether or not the determination of the final bad-path noise has been maintained, based on the value of the timer T. The situation that occurred "has passed the predetermined time ST. The predetermined time ST is a very long time compared to the recovery period.

If the result of the determination is that the predetermined time ST has not elapsed, the ignition timing calculation unit 234 advances the processing to step S156.

On the other hand, when the predetermined time period ST has elapsed, the ignition timing calculation unit 234 returns the recovery period to the cycle C when the bad channel noise has not occurred, and then advances the processing to step S156.

As shown in Fig. 16, by changing the restoration period C, the advancement speed of the ignition timing based on the determination that the knock does not occur in the knocking countermeasure control processing is changed back to the original state.

In step S156, the ECU 20 increments the timer T and ends the one-time bad noise countermeasure control process.

Through such a bad road noise countermeasure control, even if the bad road noise occurs, the accuracy of the determination of knocking is slightly lowered, and the explosion is not noticed. In the case of a shock, the advance speed of the ignition period will also be slow. Thereby, it is possible to avoid frequent occurrence of knocking afterwards.

The bad road noise countermeasure control processing in the first embodiment can be changed to the following modified examples 1 and 2.

Fig. 17 is a flowchart showing a first modification of the bad road noise countermeasure control processing.

In the example of the seventeenth aspect, the method of switching the pre-recovery amount of the ignition timing to the small value and the original value according to the bad-path noise occurrence state is used as a method of adjusting the advancement speed of the ignition timing (steps S172, S175). example.

Fig. 19 is a flowchart showing a second modification of the bad road noise countermeasure control processing.

In the example of Fig. 18, when it is determined that the bad path noise occurs, the threshold offset is switched to a smaller value (step S182), thereby avoiding occurrence of knock but determining that there is no Knocking occurs, wherein the threshold offset is a parameter that determines the critical value of the knock determination. If the bad path noise does not occur during the predetermined period, the threshold offset is changed back to the original value (S185).

The bad road noise countermeasure control process of Fig. 18 is executed by the knock determination value calculation unit 231. In this case, the final bad road determination result of the bad road noise determination unit 233 is notified to the knock determination value calculation unit 231.

The other steps in FIGS. 17 and 18 are the same as the corresponding steps in FIG. 15, and the description is omitted.

According to the bad road noise countermeasure control processing of the present embodiment, even in the output signal of the knock sensor 10 due to collision of a small stone or the like due to a bad road running or the like If foreign noise is mixed in, it is also possible to prevent knocking countermeasures from controlling the wrong operation and frequent knocking.

(implementation type 2)

In the second embodiment, as the knocking countermeasure control process and the bad road noise countermeasure control process, a method of adjusting the fuel injection amount is used instead of adjusting the ignition timing in the manner of implementing the mode 1.

The fuel injection calculation unit 235 can improve the fuel economy and the output characteristics by driving the fuel injection device of the fuel injection unit 30 such that the air-fuel ratio of the mixed gas approaches an optimum value. On the other hand, in the case where knocking occurs, the fuel injection device of the fuel injection unit 30 can be driven to increase the ratio of the fuel, thereby reducing the temperature of the combustion chamber and suppressing the occurrence of knocking.

Hereinafter, differences from the embodiment 1 will be mainly described.

<knocking countermeasure control processing>

Fig. 19 is a table showing the calculation condition of the knocking countermeasure control process of the second embodiment of the present invention.

In Fig. 19, the "fuel injection amount correction value" indicates an adjustment amount based on the reference fuel injection amount, and the reference fuel injection amount is determined based on the engine rotation speed, the amount of rotation of the adjustment handlebar, and the like. The "increased amount at the time of knocking determination" indicates the amount of increase in the fuel injection amount at the time of occurrence of knocking. The "reduction amount at the time of restoration" indicates the amount of decrease in the fuel injection amount when the recovery cycle has not been determined and the recovery cycle has not been determined.

In the second embodiment, the fuel injection calculation unit 235 executes the knocking countermeasure control processing of Fig. 6 . The fuel injection calculation unit 235 passes the calculation condition table of FIG. 19 in step S66 of the knocking countermeasure control process (FIG. 6). 72 calculates a correction value of the fuel injection amount.

For example, as shown in the column (1) of Fig. 19, if it is the restoration timing and the determination of knocking occurs, the fuel injection calculation unit 235 sets the fuel injection amount correction value as "correction value before one cycle + knocking" The amount of increase at the time of determination - the amount of reduction at the time of recovery is calculated.

As shown in the column (2) of Fig. 19, the fuel injection calculation unit 235 uses the fuel injection amount correction value as "a correction value before one cycle - a reduction amount at the time of restoration". "Calculation.

As shown in the column (3) of Fig. 19, the fuel injection calculation unit 235 uses the fuel injection amount correction value as "correction value before one cycle + knock determination", if it is not the recovery timing and the determination of knocking occurs. Increase amount" calculation.

As shown in the column (4) of Fig. 19, the fuel injection calculation unit 235 uses the fuel injection amount as the same value as the correction value before one cycle, and does not change the determination of the occurrence of the knocking. Fuel injection amount correction value.

When the fuel injection amount correction value is calculated in this way, the fuel injection calculation unit 235 drives the fuel injection device of the fuel injection unit 30 such that the fuel is injected by the amount of the fuel injection amount corrected based on the fuel injection amount correction value.

According to such knocking countermeasure control processing, when knocking is detected, the fuel injection amount is increased, and it is possible to prevent frequent knocking from occurring. Further, in the case where knocking is not detected, the fuel injection amount is gradually reduced. Through these controls, the fuel injection amount is controlled near the knock limit, and High engine 51 fuel economy and output characteristics.

In the calculation processing of the fuel injection amount correction value, the maximum value and the minimum value of the fuel injection amount correction amount can be determined so that the fuel injection amount does not exceed an appropriate range. Further, the control may be performed such that the maximum value is set when the fuel injection amount correction amount exceeds the maximum value and the minimum value is set when the fuel injection amount correction amount is lower than the minimum value.

<Bad road noise countermeasure control processing>

Fig. 20 is a flow chart showing the control method of the bad road noise countermeasure of the second embodiment.

The bad road noise countermeasure control process starts, for example, at a predetermined timing within one cycle of the engine 51, and is repeatedly executed in each cycle of the engine 51. The fuel injection calculation unit 235 executes the bad road noise countermeasure control process in parallel with the knock countermeasure control process.

When the bad road noise countermeasure control process is started, the fuel injection calculation unit 235 determines in step S201 whether or not the final determination result notified by the bad path noise determination unit 233 is "occurring".

When the result of the determination is "occurrence", the fuel injection calculation unit 235 changes the amount of reduction in the amount of recovery of the fuel injection amount to a small value for occurrence of bad-path noise in step S202. Thereby, the rate of decrease in the fuel injection amount based on the determination that the knock does not occur in the knock countermeasure control is slowed down.

Next, the fuel injection calculation unit 235 resets the timer T in step S204, and advances the processing to step S206.

On the other hand, if the result of the discrimination in step S201 is "no occurrence", the fuel injection calculation unit 235, in step S203, according to the timer T The value of the determination is made as to whether the determination of the final bad road noise has been maintained as "not occurring" and the predetermined time ST has elapsed.

If the result of the determination is that the predetermined time ST has not elapsed, the fuel injection calculation unit 235 advances the processing to step S206.

On the other hand, when the predetermined time period ST has elapsed, the fuel injection calculation unit 235 returns the amount of decrease in the amount of recovery of the fuel injection amount to the value at which the bad channel noise does not occur in step S205, and then advances the processing to step S206. By the process of step S205, the rate of decrease of the fuel injection amount based on the determination that the knock does not occur in the knocking countermeasure control is changed back to the original state.

In step S206, the ECU 20 increments the timer T and ends the primary bad road noise countermeasure control process.

By such a bad road noise countermeasure control, even if the accuracy of the occurrence of knocking is slightly lowered due to the occurrence of bad road noise, and the knocking occurrence is not noticed, the speed of fuel injection is reduced. slow. Thereby, it is possible to avoid frequent occurrence of knocking afterwards.

(Implementation type 3)

In the third embodiment, the knocking countermeasure control process and the bad road noise countermeasure control process are performed by adjusting the amount of EGR gas (hereinafter referred to as EGR amount) contained in the mixed gas instead of the implementation type. State 1 adjusts the ignition period.

The actuator control unit 236 can reduce the amount of generation of nitrogen oxides (NOx) and increase the fuel consumption rate by changing the opening degree of the EGR valve 50 and adjusting the EGR amount. Further, in the case where knocking occurs, it is possible to suppress the occurrence of knocking by increasing the EGR amount to lower the combustion temperature of the mixed gas.

Hereinafter, differences from the embodiment 1 will be mainly described.

<knocking countermeasure control processing>

Fig. 21 is a table showing the calculation condition of the knocking countermeasure control processing of the third embodiment of the present invention.

In Fig. 21, the "EGR amount correction value" indicates an adjustment value based on the reference EGR amount, and the EGR amount correction value is determined based on the engine rotation number or the like. The "increased amount at the time of knocking determination" indicates the amount of increase in the amount of EGR that is determined to be the occurrence of knocking. The "reduction amount at the time of restoration" indicates the amount of decrease in the EGR amount when the recovery cycle has not been determined to have occurred in the occurrence of knocking.

In the third embodiment, the actuator control unit 236 executes the knocking countermeasure control process of Fig. 6 . In step S66 of the knocking countermeasure control process (Fig. 6), the actuator control unit 236 calculates the correction value of the EGR amount in accordance with the calculation condition table 73 of Fig. 21 .

For example, as shown in the column (1) of Fig. 21, if it is the restoration timing and the determination of knocking occurs, the actuator control unit 236 sets the EGR amount correction value as "correction value before one cycle + knocking" The amount of increase at the time of determination - the amount of reduction at the time of recovery is calculated.

As shown in the column (2) of Fig. 21, if it is the restoration timing and the determination that knocking has not occurred, the actuator control unit 236 sets the EGR amount correction value as "a correction value before one cycle - a reduction amount at the time of restoration" "Calculation.

As shown in the column (3) of Fig. 21, if it is not the restoration timing and the determination of knocking occurs, the actuator control unit 236 sets the EGR amount correction value as "correction value before one cycle + knock determination" Increase amount" calculation.

As shown in column (4) of Figure 21, if it is not the recovery timing and is When there is no determination that the knocking has occurred, the actuator control unit 236 sets the EGR amount as the same value as the correction value before one cycle, without changing the EGR amount correction value.

When the EGR amount correction value is calculated in this way, the actuator control unit 236 drives the EGR valve 50 so as to recirculate the combustion gas having the corrected EGR amount.

According to such a knocking countermeasure control process, when it is determined that knocking has occurred, the EGR amount is increased, and it is possible to prevent frequent knocking from occurring. Further, when it is not determined that knocking has occurred, the EGR amount is gradually decreased. By these controls, the EGR amount is controlled near the knock limit, and the fuel economy and output characteristics of the engine 51 can be improved.

In the calculation processing of the EGR amount correction value, the maximum value and the minimum value of the EGR amount correction amount can be determined such that the EGR amount does not exceed an appropriate range. Further, the control may be performed such that the maximum value is set when the EGR amount correction amount exceeds the maximum value, and the minimum value is set when the EGR amount correction amount is lower than the minimum value.

<Bad road noise countermeasure control processing>

Fig. 22 is a flow chart showing the control method of the bad road noise countermeasure of the third embodiment.

The bad road noise countermeasure control process starts, for example, at a predetermined timing within one cycle of the engine 51, and is repeatedly executed in each cycle of the engine 51. By the actuator control unit 236, the bad road noise countermeasure control process is executed in parallel with the knock countermeasure control process.

When the bad road noise countermeasure control process is started, the actuator control unit 236 determines the final determination notified by the bad path noise determination unit 233 in step S221. Whether the result is "occurring".

When the determination result is "occurring", the actuator control unit 236 changes the amount of reduction in the amount of restoration of the EGR amount to a small value for the occurrence of the bad path noise in step S222. As a result, the rate of decrease in the EGR amount based on the determination that the knock does not occur in the knocking countermeasure control is slowed down.

Next, the actuator control unit 236 resets the timer T in step S224, and advances the processing to step S226.

On the other hand, if the result of the determination in step S221 is "no occurrence", the actuator control unit 236 determines in step S223 whether or not the determination of the final bad-path noise has been maintained based on the value of the timer T. The case of not occurring has passed the predetermined time ST. The predetermined time ST is a very long time compared to the recovery period.

If the result of the determination is that the predetermined time ST has not elapsed, the actuator control unit 236 advances the processing to step S226.

On the other hand, when the predetermined time period ST has elapsed, the actuator control unit 236 changes the amount of decrease in the amount of restoration of the EGR amount back to the value at which the bad channel noise does not occur, and then advances the processing to step S226. In the process of step S225, the rate of decrease in the EGR amount based on the determination that the knock does not occur in the knocking countermeasure control is changed back to the original state.

In step S226, the ECU 20 increments the timer T and ends the primary bad road noise countermeasure control process.

By such a bad road noise countermeasure control, even if the accuracy of the occurrence of knocking is slightly lowered due to the occurrence of bad road noise, and the knocking is not noticed, the speed of decreasing the EGR amount is also slowed down. Thereby being able to Avoid frequent knocking afterwards.

As described above, according to the ECU 20, the power unit, and the straddle-type vehicle 1 of the present embodiment, even in the crankcase of the collision engine 51 or the power transmission portion 52 such as Xiaoshi, the output of the knock sensor is mixed. In the case of road noise, it can also be detected. Further, the bad road noise countermeasure control processing can switch the content of the knocking countermeasure control processing when the bad road noise is detected. Thereby, even if the determination accuracy of the occurrence of knocking is slightly lowered due to the occurrence of the bad road noise, it is possible to prevent the occurrence of knocking frequently.

The embodiments of the present invention have been described above.

The configurations and methods that are specifically described in the above-described embodiments can be appropriately changed without departing from the scope of the invention.

For example, the straddle type vehicle according to the present invention is not limited to the motorcycle of the type shown in Fig. 1, and includes a Scooter type vehicle that can also ride the knees together. Further, the straddle type vehicle according to the present invention may be a straddle type type, and is not limited to the second wheel, and may be a three-wheel or four-wheel type vehicle.

Further, in the above-described embodiment, the engine is described as an example of an engine that uses four strokes and is air-cooled. However, the internal combustion engine may be a two-stroke engine. Further, the engine of the present invention may be applied to a water-cooled engine.

Further, in the above-described embodiment, the configuration of the non-resonant type sensor is described as an example of the knock sensor. However, a resonance type knock sensor in which the detection level of the resonance band is increased may be used. In this case, the resonance band is set to be the same band as the pass band of the filter unit 212 of the implementation type. The filter processing unit 212 can be omitted.

Further, in the above-described embodiment, when it is determined that the occurrence of the bad-path noise occurs, the knocking countermeasure control process is further performed in addition to the control parameter (ignition timing, fuel injection amount, EGR amount, etc.). example. However, when it is determined that the bad-path noise occurs, the control parameter (ignition period, fuel injection amount) can be performed in such a manner that the knocking can be sufficiently prevented regardless of the result of the occurrence of the knocking or the occurrence of the knocking. Control of the stable area or the EGR amount).

Further, the knocking countermeasure control process and the bad road noise countermeasure control process may be processes in which the respective processes of the above-described embodiments 1 to 3 are combined.

Further, in the above-described embodiment, the first obtaining means, the second obtaining means, and the third obtaining means are formed by a hard body to form a burst in a specific period of one cycle of the engine. An example of the composition of the signal of the shock sensor. However, these units can also be constructed of software. Further, in the above-described embodiment, as the first control means, a mode in which the following techniques are mainly realized by software is performed: determination of occurrence of knocking, and combustion control of the engine based on the result of the determination. Further, as the second control means, a mode in which the following techniques are mainly realized by software is performed: determination of occurrence of bad-path noise, and change of combustion control of the engine based on the determination result. However, the first control means and the second control means can be implemented by hardware, for example, using a digital signal processor or a sequencer or the like.

Further, in the above-described embodiment, the configuration of the detection signal of the knock sensor 10 is taken in a specific period, the configuration for determining the occurrence of knocking, and the manner of suppressing knocking in the case where knocking occurs. Control engine 51 The configuration for determining the occurrence of the bad road noise and the configuration for changing the control content of the engine 51 based on the determination result of the occurrence of the bad road noise are stored in one ECU 20 as an example. However, it is also possible to connect one or a plurality of these configurations by signal lines or the like separately from each other.

Further, in the present invention, the "determination of occurrence of knocking" includes various modes. For example, the determination of so-called knocking includes determining the manner in which knocking occurs from the detection signal of the knock sensor. In addition, the determination of the occurrence of knocking also includes a method of determining that knocking has not occurred from the detection signal of the knock sensor. The method of determining the occurrence of knocking includes the following method: comparing the value obtained by processing the detection signal of the knock sensor with the value that has occurred as knocking and is a reference value determined in advance by experiments. The reference value is a value that has occurred as knocking, and a value calculated by a method determined in advance by an experiment may be used. Further, the method of determining the occurrence of knocking includes a method of comparing the value obtained by processing the detection signal of the knock sensor with the reference value, and when the former is large, it is determined that knocking has occurred. Further, the method of determining the occurrence of knocking includes a method of determining that knocking does not occur when the comparison result between the value obtained by processing the detection signal of the knock sensor and the reference value is small.

Further, in the present invention, the "determination of occurrence of foreign noise" includes various aspects. For example, the determination of occurrence of foreign noise includes a method of determining that a foreign noise has occurred, a method of determining that no external noise has occurred, or a method of determining both of them. The method for determining the occurrence of alien noise includes the following method: comparing the value obtained by processing the detection signal of the knock sensor with the value generated as the external noise and comparing it with the reference value determined in advance by the experiment. As a reference value, it is a value that has occurred as a foreign noise, and can also be used. The value calculated by the method determined in advance by experiments. Further, the method for determining the occurrence of the external noise includes a method of comparing the value obtained by processing the detection signal of the knock sensor with the reference value, and when the former is large, it is determined that foreign noise has occurred. Further, the method of determining the occurrence of knocking includes a case where it is determined that the external noise does not occur when the comparison result between the value obtained by processing the detection signal of the knock sensor and the reference value is small.

[Industrial availability]

The present invention can be applied to, for example, a straddle-type vehicle such as a motorcycle, a power unit thereof, and an ECU.

10‧‧‧knock sensor

20‧‧‧ ECU (Engine Control Unit)

21‧‧‧knock feature extraction circuit

22‧‧‧Interface circuit

23‧‧‧Microcomputer

231‧‧‧knock determination value calculation unit

232‧‧‧Detonation Judgment Department

233‧‧‧ Bad Road Noise Judgment Department

234‧‧‧Ignition Period Computing Department

235‧‧‧Fuel injection calculation department

236‧‧‧Actuator Control Unit

237‧‧"Window Control Department

30‧‧‧fuel injection unit

40‧‧‧Ignition unit

50‧‧‧EGR valve (exhaust gas recirculation valve)

60‧‧‧Crank angle sensor

Claims (12)

A control device for an internal combustion engine is a control device for detecting a signal input from the knock sensor to the internal combustion engine, the knock sensor detecting vibration of an internal combustion engine mounted in a straddle type vehicle, the control device for the internal combustion engine having: a first obtaining means And during the first period of the foregoing internal combustion engine, the signal output from the knock sensor is taken in a first period in which knocking may occur; and the second obtaining means is in the first period of the internal combustion engine The signal output from the knock sensor is taken in the second period, and the second period is at least a part of a period after the first period is removed and the occurrence period of the noise caused by the mechanical vibration of the internal combustion engine is removed; a control means for determining occurrence of knocking based on a signal taken by the first obtaining means, and controlling the internal combustion engine to suppress knocking in a case where knocking occurs; and second control means And determining, based on the signal taken by the second obtaining means, the external noise caused by the external condition of the straddle type vehicle It occurs, and changes the contents of the first control means controls the internal combustion engine based on the determination result. The control device for an internal combustion engine according to claim 1, further comprising: a third obtaining means for taking in a third period overlapping the occurrence period of the mechanical vibration in one cycle of the internal combustion engine a signal output from the knock sensor, and the second control means determines based on a signal taken by the second obtaining means and a signal taken by the third obtaining means The occurrence of the aforementioned foreign noise. The control device for an internal combustion engine according to claim 1, wherein the second control means includes statistical processing means for calculating statistical information of a signal taken in by the second obtaining means, and the second The control means determines the occurrence of the aforementioned alien noise based on the aforementioned statistical information. The control device for an internal combustion engine according to claim 3, wherein the statistical processing means calculates the degree of dispersion of the signal level taken in by the second obtaining means as the statistical information. The control device for an internal combustion engine according to claim 2, wherein the second control means includes statistical processing means for calculating statistical information of signals taken in by the second obtaining means and the third obtaining means And the second control means determines the occurrence of the foreign noise based on the statistical information. The control device for an internal combustion engine according to claim 5, wherein the statistical processing means calculates a first statistical value and a second statistical value as the statistical information, wherein the first statistical value is to be obtained by the second obtaining means a statistical value obtained by averaging a plurality of signal levels respectively taken in a plurality of cycle periods, wherein the second statistical value is a plurality of signals respectively taken in a plurality of cycle periods by the third obtaining means The statistic value obtained by averaging the level, and the second control means determines the occurrence of the foreign noise based on the relationship between the first statistic value and the second statistic value. The control device for an internal combustion engine according to claim 1, wherein the second control In the case where it is determined that external noise is generated, the control means changes the control parameter of the internal combustion engine in a direction in which knocking is suppressed. The control device for the internal combustion engine according to the seventh aspect, wherein the first control means performs the advance control of stepping the combustion timing of the internal combustion engine stepwise when the determination of knocking occurrence is not continuous, and The second control means, when it is determined that external noise is generated, slows the speed at which the combustion timing is advanced in the advance control. The control device for an internal combustion engine according to claim 7, wherein the first control means includes a process of determining a occurrence of knocking by comparing a signal level taken in by the first obtaining means with a critical value. And the second control means changes the determination method of the threshold value when it is determined that external noise is generated. The control device for an internal combustion engine according to claim 7, wherein the second control means switches the control of the internal combustion engine to the control for suppressing knocking regardless of the determination result of knocking in the case where it is determined that external noise is generated . A power unit of a straddle-type vehicle includes: an internal combustion engine mounted on a straddle-type vehicle; a knock sensor that detects vibration of the internal combustion engine; and a control device for the internal combustion engine according to claim 1. A straddle-type vehicle comprising: an internal combustion engine, at least a portion of which is disposed below a seat cushion surface; a knock sensor that detects vibration of the internal combustion engine; and a control device for the internal combustion engine according to claim 1.