JP6482410B2 - Engine stroke determination device, control device, and engine stroke determination method - Google Patents

Description

  The present invention relates to an engine stroke determination device, a control device, and an engine stroke determination method.

  In order to appropriately control the operation of the engine, a technique for determining the current stroke of the engine in operation is known (see, for example, Patent Document 1).

Japanese Patent No. 4093682

  However, it is difficult to determine the stroke at the initial stage when the crankshaft starts to rotate by the starter motor when the engine is started. For example, in a four-cycle engine, the crankshaft rotates twice to perform one-cycle operation consisting of four strokes (intake, compression, combustion, and exhaust), so crank angle information can be acquired and intake pressure changes due to combustion Until this occurs, the stroke cannot be determined. In a two-stroke engine, the stroke cannot be determined unless the crankshaft rotates to a rotation angle at which the crank angle sensor can detect the notch of the crankshaft rotor.

  Accordingly, an object of the present invention is to make it possible to determine the stroke at an early stage when the engine is started.

  An engine stroke determination device according to an aspect of the present invention includes a determination unit that determines a stroke during operation of an engine based on at least a crank angle, and a stop stroke for recognizing a stroke when the crankshaft stops rotating. And a recording controller that records information in a storage device, and the determination unit determines a stroke when the crankshaft starts rotating based on the stop-time stroke information recorded in the storage device.

  According to the above configuration, at the start of rotation of the crankshaft, it is possible to grasp from which stroke the engine operation starts by referring to the stroke information at the time of stop, and realize early stroke discrimination Is possible.

  After the crankshaft starts rotating and combustion in the combustion stroke is started, the determiner determines a stroke during operation of the engine based on a physical quantity that changes due to combustion in the cylinder of the engine. Also good.

  According to the above configuration, the stroke can be determined with higher accuracy based on a physical quantity (for example, intake pressure, engine vibration, etc.) that changes due to combustion. Specifically, at the start of rotation of the crankshaft, the stroke is determined by referring to the stop stroke information and the crank angle information recorded in the storage device, and after the combustion in the combustion stroke starts, The stroke can be determined by referring to the angle information and the physical quantity.

  The stop-time stroke information may include information on a crank angle from a base point angle set in a stroke serving as a base point.

  According to the above configuration, the crank angle (one cycle of the stroke operation of the engine) with the reference point angle set to zero before the reference point angle is detected by the sensor by referring to the stop stroke information at the start of rotation of the crankshaft. For example, in the case of a 4-stroke engine, an angle within a range of 0 ° to 720 ° can be grasped. In addition, by recording the crank angle from the base point angle as stop-time stroke information, the control timing can be set finely from the start of crankshaft rotation.

  The storage device may be a non-volatile memory, and the recording controller may record the stop process information in the non-volatile memory.

  According to the said structure, even if a power supply is turned off, the record of stop time stroke information can be maintained.

  The power supply controller further controls power supply to the recording controller, and the power supply controller records the stroke when the rotation of the crankshaft is stopped in the storage device until the recording controller records the stroke when the crankshaft is stopped. You may maintain the power supply to.

  According to the above configuration, it is possible to prevent the power supply to the recording controller from being stopped before the stroke when the rotation of the crankshaft is stopped is recorded in the storage device.

  An engine control device according to another aspect of the present invention includes: the stroke determination device; and an engine controller that controls the engine based on a determination result of the determination device of the stroke determination device. It is a 4-stroke engine.

  According to the above configuration, it is possible to start appropriate engine control at an early stage according to the stroke determined at an early stage.

  The engine controller may command fuel injection to a fuel injector of the engine when the determination unit determines an intake stroke after the crankshaft starts rotating.

  According to the above configuration, unnecessary fuel injection in a stroke other than the intake stroke is reduced by instructing fuel injection in the intake stroke based on the stroke determined from the start of rotation of the crankshaft of the four-stroke engine. Can contribute to exhaust gas improvement.

  The engine controller may increase the fuel injection amount in one cycle when a predetermined startability improving condition is satisfied, compared to when the startability improving condition is not satisfied.

  According to the above configuration, it is possible to improve startability when a predetermined condition is satisfied while reducing unnecessary fuel injection in a stroke other than the intake stroke.

  The engine controller may command the ignition device of the engine to ignite when the determination unit determines a combustion stroke after the crankshaft starts rotating.

  According to the above configuration, unnecessary ignition in a stroke other than the combustion stroke can be eliminated by instructing ignition in the combustion stroke based on the stroke determined from the start of rotation of the crankshaft of the 4-stroke engine. The unburned gas can be prevented from igniting in a stroke other than the combustion stroke.

  An engine stroke determination method according to another aspect of the present invention includes a stroke determination step for determining a stroke during operation of an engine based on at least a crank angle, and a stop time for recognizing a stroke when the crankshaft stops rotating. And a recording step of recording stroke information, wherein the determination step determines a stroke when the crankshaft starts to rotate based on the recorded stroke-time information.

  According to the method, at the start of rotation of the crankshaft, it is possible to grasp from which stroke the engine operation starts by referring to the stroke information at the time of stop, and realize early stroke determination. Is possible.

  According to the present invention, it is possible to determine the stroke at an early stage when the engine is started.

It is a block diagram explaining the engine, ECU, etc. of the vehicle concerning a 1st embodiment. It is a flowchart explaining the recording procedure of the stroke at the time of an engine stop shown in FIG. It is a flowchart explaining the process of the stroke | distance determination at the time of engine starting shown in FIG. 1, and an engine control. (A) is a timing chart explaining the timing of fuel injection and ignition at the time of engine start of a comparative example, (b) is a timing chart explaining the timing of fuel injection and ignition at the time of engine start shown in FIG. . It is a flowchart explaining the recording procedure of the process at the time of a stop at the time of the engine stop which concerns on 2nd Embodiment. It is a flowchart explaining the process discrimination | determination at the time of engine starting which concerns on 3rd Embodiment, and the procedure of engine control. It is a flowchart explaining the process discrimination | determination at the time of engine starting which concerns on 4th Embodiment, and the procedure of engine control. It is a timing chart explaining the timing of fuel injection and ignition at the time of engine start concerning a 4th embodiment. It is a flowchart explaining the procedure of the engine control at the time of the engine starting which concerns on 5th Embodiment. It is a flowchart explaining the recording procedure of the process at the time of a stop at the time of the engine stop which concerns on 6th Embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram illustrating an engine E, an ECU 20 and the like of the vehicle 1 according to the first embodiment. As shown in FIG. 1, the vehicle 1 includes a four-stroke engine E that is a traveling drive source, and an ECU 20 that controls the engine E. The vehicle 1 is, for example, a motorcycle. The engine E includes a cylinder 2, and a piston 3 is accommodated in the cylinder 2 so as to be able to reciprocate. A crankshaft 5 is connected to the piston 3 via a connecting rod 4. A rotor 6 is fixed to the crankshaft 5 so as to face the crank angle sensor 7. A plurality of protrusions are provided on the outer peripheral edge of the rotor 6 at a predetermined interval in the circumferential direction, and a part of the outer peripheral edge has a notch (notch) having an interval wider than the predetermined interval. One is provided.

  The crank angle sensor 7 is an electromagnetic pickup type, and can detect a base angle of the crank angle (for example, piston top dead center) by detecting a missing portion. The crank angle sensor 7 can detect the amount of angular displacement from the base point angle by counting the protrusions of the rotor 6 detected after detecting the missing portion of the rotor 6. In the present embodiment, the “crank angle” means a rotation angle of the crankshaft 5 and is defined by a value of 0 ° or more and less than 360 °.

  A combustion chamber 8 is formed in the cylinder 2 above the piston 3. The engine E is provided with an intake port 9 and an exhaust port 10 that communicate with the combustion chamber 8. An intake valve 11 is disposed in the intake port 9, and an exhaust valve 12 is disposed in the exhaust port 10. The intake port 9 is provided with a fuel injector 13 for injecting fuel into the intake passage. The intake port 9 is provided with an intake pressure sensor 14 for detecting the pressure of intake air (intake pressure) flowing through the intake passage. The engine E is provided with an ignition device 15 for igniting the air-fuel mixture in the combustion chamber 8.

  The ECU 20 includes a crank angle detection unit 21, an intake pressure detection unit 22, a determination unit 23 (determination unit), an engine control unit 24 (engine controller), a recording control unit 25 (recording control unit), and a non-volatile type. And a memory 26 (storage device). The crank angle detector 21 detects the crank angle based on a signal from the crank angle sensor 7. The intake pressure detection unit 22 detects the intake pressure of the intake port 9 based on a signal from the intake pressure sensor 14.

  Based on the crank angle detected by the crank angle detection unit 21 and the physical quantity that changes due to combustion in the combustion chamber 8 of the engine E, the determination unit 23 performs a stroke (intake, compression, combustion, Exhaust) is determined. That is, only the information from the crank angle sensor 7 has the same piston position in the intake stroke and the combustion stroke and the same piston position in the compression stroke and the exhaust stroke. For example, the detected base angle is the piston top dead center position at the start of the intake stroke, or the piston at the start of the combustion stroke. It cannot be determined whether the position is at the top dead center. However, it is possible to specify the current stroke of the engine E during operation by referring to the physical quantity in which different values appear in the front rotation and the reverse rotation.

  In the present embodiment, the determination unit 23 uses, for example, the intake pressure detected by the intake pressure detection unit 22 as a physical quantity that changes due to combustion in the combustion chamber 8 of the engine E. The intake pressure changes in accordance with a change in the combustion stroke, and for example, the intake pressure becomes minimum during the intake stroke. Therefore, the determination unit 23 can determine that the time when the intake pressure reaches the minimum value is the intake stroke.

  The determination unit 23 sets the base angle set at the start of the stroke as the base point to 0 °, and the crank angle in one cycle including the four strokes of intake, compression, combustion, and exhaust ranges from 0 ° to less than 720 °. It is preferable to specify the current stroke from the crank phase angle. For example, in one cycle, the determination unit 23 sets the crank phase angle that becomes the piston top dead center just before the start of the intake stroke to 0 °, and sets the crank phase angle that becomes the piston top dead center just before the start of the combustion stroke thereafter. When the top dead center of the piston immediately before the start of the intake stroke of the next cycle is reached, the crank phase angle is reset to 0 °. That is, in the present embodiment, the “crank phase angle” is set corresponding to the stroke, and means an angular displacement amount in which the crankshaft 5 is angularly displaced with respect to the base angle, and is a value between 0 ° and less than 720 °. Defined.

  The engine control unit 24 controls the engine E based on the determination result of the determination unit 23. Specifically, the engine control unit 24 controls the operation timing of the fuel injector 13 and the ignition device 15 based on the stroke (crank phase angle) determined by the determination unit 23. The engine control unit 24 commands the fuel injector 13 to inject fuel during the intake stroke determined by the determination unit 23, and commands the ignition device 15 to perform ignition during the combustion stroke determined by the determination unit 23.

  The recording control unit 25 records, in the nonvolatile memory 26 (storage device), stop-time stroke information capable of recognizing the stroke when the stop command is given to the engine E during operation and the crankshaft 5 stops rotating. Specifically, the recording control unit 25 stores the crank phase angle when the rotation of the crankshaft 5 is stopped in the nonvolatile memory 26 as stop-time stroke information. The nonvolatile memory 26 is a storage device that retains stored contents even when power is not supplied. In the present embodiment, the nonvolatile memory 26 is configured to be writable and overwritten when power is supplied, and for example, an EEPROM or a flash memory is used.

  The vehicle 1 further includes a power supply control device 30 (power supply controller), a power source 31, and an ON-OFF operation device 32. The power supply control device 30 performs ON-OFF control of power supply from the power source 31 (for example, a battery) to the ECU 20 in accordance with the operation of the ON-OFF operation device 32 by the driver. For example, when the driver operates the ON-OFF operation device 32 to issue a power OFF command, an engine stop command is issued to the engine control unit 24, and the recording control unit 25 determines the stroke when the crankshaft rotation is stopped. The power supply control device 30 maintains power supply to the ECU 20 (recording control unit 25) until recording in the memory 26, and stops the power supply after a predetermined time has elapsed.

  In the present embodiment, the crank angle detection unit 21, the intake pressure detection unit 22, the determination unit 23, the recording control unit 25, the non-volatile memory 26, and the power supply control device 30 correspond to the engine stroke determination device 27, and the ECU 20 and The power supply control device 30 corresponds to the engine control device 28.

  Next, a procedure for recording a stop stroke when stopping the engine E during operation will be described. FIG. 2 is a flowchart for explaining a recording procedure of a stop process when the engine E shown in FIG. 1 is stopped. As shown in FIGS. 1 and 2, the ECU 20 determines whether or not the engine E is in operation based on a signal from the crank angle detector 21 (step S1). The operation of the engine E means a state in which the engine E is operating as an internal combustion engine through a combustion stroke. If no, the process returns to step S1. In the case of Yes, the ECU 20 determines whether or not a power OFF command is issued from the ON-OFF operating device 32 (step S2). If no, the process returns to step S2. In the case of Yes, ECU20 stops the engine control by the engine control part 24, and stops the engine E (step S3). At this time, even if the engine control by the engine control unit 24 is stopped, the crankshaft 5 naturally stops after rotating for a while due to inertia.

  Next, the ECU 20 determines whether or not a predetermined standby time has elapsed since the power OFF command was issued (step S4). The waiting time is set to a time required for the crankshaft 5 to stop after the control of the engine E is stopped or longer. In the case of No, it is determined that there is a possibility that the inertial rotation of the crankshaft 5 has not ended, and the process returns to step S4. In the case of Yes, the recording control unit 25 considers that the crankshaft 5 is stopped because a sufficient time has elapsed from the power-off command, and the stroke (crank phase angle) when the standby time has elapsed is stopped. The process information is recorded in the nonvolatile memory 26 (step S5). Next, the recording control unit 25 notifies the power supply control device 30 of the recording completion, and the power supply control device 30 that has received the notification stops power supply to the ECU 20 (step S6).

  Next, a procedure for determining the stroke when starting the stopped engine E will be described. FIG. 3 is a flowchart for explaining the procedure of stroke determination and engine control when the engine E shown in FIG. 1 is started. As shown in FIGS. 1 and 3, the power supply control device 30 determines whether or not a power ON command is issued from the ON-OFF operation device 32 (step S11). In No, it returns to step S11. In the case of Yes, the electric power feeding control apparatus 30 starts the electric power feeding to ECU20 (step S12). Next, the recording control unit 25 reads out the stop-time process information recorded in the nonvolatile memory 26 at the previous engine stop (step S5) from the nonvolatile memory 26 (step S13).

  The determination unit 23 determines the stroke (crank phase angle) at the previous engine stop based on the read stop stroke information, and the stroke (initial crank phase) immediately before the start of rotation of the crankshaft 5 at the current engine start. Corner). Note that the crankshaft 5 of the engine E can rotate even when it is not in operation. That is, when the engine E is started, there is a state in which the crankshaft 5 is angularly displaced by the power supplied from the cell motor or the driver to the crankshaft 5 before passing through the first combustion stroke (before engine operation).

  Next, the determination unit 23 determines whether an engine start command has been issued (step S14). If no, the process returns to step S14. In the case of Yes, the determination part 23 performs stroke determination (step S15). Immediately before the crankshaft 5 starts to rotate, the determination unit 23 uses the stroke of the previous stop stroke information read from the nonvolatile memory 26 as an initial stroke, and the first combustion stroke is performed after the crankshaft 5 starts rotating. Until the engine E is started, the current stroke is determined from the crank angle detected by the crank angle detector 21.

  That is, the determination unit 23 assumes that the crank phase angle counted by the crank detection unit 21 from the rotation stop state of the crankshaft 5 is a count angle (N °), and the initial angle (indicated by the stroke-time process information) as the crank phase angle ( The total angle (n ° + N °) obtained by adding the count angle (N °) to (n °) is determined as the crank phase angle before starting the engine. When the total angle reaches any one of angles set in advance as the start angle of each stroke, it is determined that the corresponding stroke has been reached.

  Then, the engine control unit 24 controls the operation timing of the fuel injector 13 and the ignition device 15 based on the stroke determination result (step S16). That is, the engine control here is control before the first combustion stroke is performed.

  Next, the determination unit 23 determines whether or not the first combustion stroke has been performed after the engine start command is issued (step S17). For example, when the intake pressure detection unit 22 detects that the intake pressure is less than a predetermined threshold, the determination unit 23 determines that the current intake stroke is performed and the first combustion stroke is performed two strokes before the intake stroke. judge. The threshold value is larger than the intake pressure of the intake stroke immediately after combustion actually occurs in the combustion chamber 8, and the first combustion stroke is not performed (after the crankshaft 5 starts to rotate). It is set to a value smaller than the intake pressure of the intake stroke at the stage where combustion in the combustion chamber 8 has not yet occurred.

  If No in step S17, the process returns to step S15. If Yes in step S17, the determination unit 23 determines the stroke of the engine E based on the crank angle detected by the crank angle detection unit 21 and the intake pressure detected by the intake pressure detection unit 22 (step S18). ). That is, after the combustion stroke is performed, the determination unit 23 is not based on the sum angle, but based on the count angle α ° counted from the base point angle and the stroke information known from the intake pressure detected by the intake pressure detection unit 22. To obtain the crank phase angle. Specifically, if the determination unit 23 determines that the intake pressure has decreased after determining that the reference point angle has been passed, the determination unit 23 sets the reference point angle (piston top dead center just before the start of the intake stroke) before the intake pressure decrease to 0 °. The count angle α ° from the base point angle is determined as the crank phase angle. In this way, by switching the stroke determination method before and after the first combustion stroke, even when there is an error in the crank phase angle determined before the first combustion stroke, the stroke is accurately performed after engine startup. Can be determined. For example, even when the crankshaft 5 is angularly displaced by moving the vehicle body after the stop stroke information is recorded in the nonvolatile memory 26, the determination result can be corrected.

  Then, the engine control unit 24 controls the operation timing of the fuel injector 13 and the ignition device 15 based on the stroke determination result (step S19). That is, the engine control here is control after the first combustion stroke is performed.

  FIG. 4A is a timing chart for explaining the timing of fuel injection and ignition when starting the engine of the comparative example, and FIG. 4B is the timing of fuel injection and ignition when starting the engine E shown in FIG. It is a timing chart explaining time. As shown in FIG. 4A, in the comparative example in which only the information on the crank angle and the intake pressure is used for the stroke determination without using the stroke-time stroke information, the crankshaft 5 starts to rotate when the engine is started, and the crank angle detector 21. Even if the base angle BA is detected by the above, if the first combustion stroke is not performed and the intake pressure detected by the intake pressure detection unit 22 does not become less than the threshold value, the current state is the table rotation (intake / compression). ) Or reverse rotation (combustion / exhaust). Therefore, in the comparative example, fuel injection and ignition are commanded in both the intake stroke and the combustion stroke until it is determined that the first combustion stroke is performed. That is, the fuel injection performed in the combustion stroke is wasted, and undesired combustion can occur due to the ignition performed in the intake stroke. Then, after the first combustion stroke is performed and the intake pressure detected by the intake pressure detection unit 22 becomes less than the threshold value, the stroke determination is performed based on the crank angle and the intake pressure. Thereafter, only the intake stroke is performed. Combustion injection is performed, and ignition is performed only in the combustion stroke.

  On the other hand, as shown in FIG. 4B, in the present embodiment, since the initial stroke at the time of starting the engine is known from the stop stroke information read from the non-volatile memory 26, the determination unit 23 detects the intake pressure fluctuation. It is possible to determine the current stroke from before being detected. That is, the determination unit 23 can grasp the current stroke before the crankshaft 5 starts rotating and reaches the first combustion stroke by referring to the stop stroke information (note that the determination unit 23 is By referring to the stop stroke information, the current crank angle can be grasped before the base angle BA is detected by the crank angle detector 21.) Therefore, the engine control unit 24 commands fuel injection only in the intake stroke, and commands ignition only in the combustion stroke. When sufficient intake pressure fluctuations appear after the combustion stroke, stroke determination is performed based on the crank angle and the intake pressure, and engine control is performed.

  According to the configuration described above, when the crankshaft 5 starts to rotate, the operation of the engine E can be performed before the first combustion stroke by referring to the stop stroke information recorded in the nonvolatile memory 26. It is possible to grasp whether the process starts from the process, and it is possible to realize an early process determination. Further, engine control corresponding to the stroke can be started early. Further, when the rotation of the crankshaft 5 is started, the stroke is determined by referring to the stop stroke information and the crank angle information recorded in the non-volatile memory 26. After the combustion stroke, the stroke is changed by the crank angle information and the combustion. It is possible to accurately determine the stroke by referring to the physical quantity to be performed. Further, an engine that completes all strokes by rotating the crankshaft 5 more than twice (in this embodiment, a 4-stroke engine) is used, and stroke discrimination is difficult with the crank angle sensor 7 alone. The process can be easily determined by the method.

  The stop stroke information recorded in the non-volatile memory 26 includes information on the crank phase angle from the base point angle set in the base stroke. Therefore, when the rotation of the crankshaft 5 is started, the stop stroke process is performed. By referring to the information, the crank phase angle with the base point angle set to zero can be grasped before the base point angle is detected by the crank angle sensor 7. Then, by recording the crank phase angle from the base point angle as stop time stroke information, the control timing can be set finely from the start of rotation of the crankshaft 5. That is, by recording the crank phase angle as the stroke information at the time of stop, more detailed information can be obtained than when the stroke itself is recorded, and it can be used for fine control or judgment.

  Further, since the power supply to the ECU 20 is maintained from when the power OFF command is issued until the stroke when the rotation of the crankshaft 5 is stopped is recorded in the nonvolatile memory 26, the stroke when the rotation of the crankshaft 5 is stopped is nonvolatile. It is possible to prevent power supply to the ECU 20 from being stopped before recording in the volatile memory 26. Since the power supply control device 30 stops power supply to the ECU 20 after a predetermined standby time has elapsed since the power-off command is issued, even when the crank angle of the engine E changes due to inertia after the power-off command, If the change occurs during the standby time, the actual final stroke when the engine E is stopped can be accurately recorded in the nonvolatile memory 26.

  In addition, since early stroke discrimination is realized, unnecessary fuel injection in a stroke other than the intake stroke can be reduced, which contributes to exhaust gas improvement and is unnecessary in a stroke other than the combustion stroke. Ignition can be eliminated and unburned gas can be prevented from igniting in a stroke other than the combustion stroke.

(Second Embodiment)
FIG. 5 is a flowchart for explaining the procedure for recording the stroke of the engine according to the second embodiment. In addition, about the structure which is common in 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIG. 5, steps S1 to S3 are the same as steps S1 to S3 in FIG. 2 (first embodiment). When engine control stops in step S3, the ECU 20 determines whether or not the rotation of the crankshaft 5 has stopped (step S21). For example, the ECU 20 rotates the crankshaft 5 when there is no change in the crank angle detected by the crank angle detector 21 (for example, when no pulse signal is received from the crank angle sensor 7 for a predetermined time or more). Determined to have stopped. If no, the process returns to step S4. In the case of Yes, the recording control unit 25 records the latest stroke (crank angle) in the non-volatile memory 26 as stroke-time stroke information (step S5), and receives the notification of recording completion from the ECU 20 and the power feeding control device 30. However, power supply to the ECU 20 is stopped (step S6).

  That is, the power supply controller 30 maintains power supply to the ECU 20 until the recording controller 25 records the stroke when the rotation of the crankshaft 5 is stopped in the nonvolatile memory 26. According to this configuration, power supply to the ECU 20 is stopped after confirming that the change in the crank angle is eliminated. Therefore, even when the crank angle of the engine E changes due to inertia after the power OFF command, the engine E is stopped. The actual final process at the time can be recorded accurately.

(Third embodiment)
FIG. 6 is a flowchart for explaining the procedure of stroke determination and engine control when starting the engine according to the third embodiment. In addition, about the structure which is common in 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. Since the contents of steps S11 to S15 and steps S16 to S19 of this embodiment are the same as the contents of steps S11 to S15 and steps S16 to 19 of the first embodiment, detailed description thereof is omitted.

  As shown in FIG. 6, the determination unit 23 obtains the crank phase angle based on the stop stroke information read from the nonvolatile memory 26 and the crank angle detected by the crank angle detection unit 21 (step S15). Then, it is determined whether or not the crank phase angle is the correction timing (step S31). For example, the correction timing is the time when the crank angle sensor 7 detects the missing portion of the rotor 6, that is, the time when the base angle of the crank angle is detected. In the case of Yes in step S31, when the crank phase angle at the correction timing is not 0 ° or 360 °, the determination unit 23 corrects the crank phase angle to a value closer to 0 ° or 360 °. (Step S32), the process returns to Step S15. In the case of No in step S31, the determination unit 23 determines whether or not the crank phase angle is the engine control timing (step S33). Specifically, the determination unit 23 determines whether it is an ignition timing or a combustion injection timing. In the case of Yes, the engine control part 24 implements ignition or combustion injection (step S16), and in No, it returns to step S15. In this way, it is possible to improve the accuracy of the crank phase angle before it is determined that the first combustion stroke has been performed at the time of engine start.

(Fourth embodiment)
FIG. 7 is a flowchart for explaining the procedure of stroke determination and engine control when starting the engine according to the fourth embodiment. FIG. 8 is a timing chart for explaining the timing of fuel injection and ignition when starting the engine according to the fourth embodiment. In addition, about the structure which is common in 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. Since the contents of steps S11 to S15 and steps S16 to S19 of this embodiment are the same as the contents of steps S11 to S15 and steps S16 to 19 of the first embodiment, detailed description thereof is omitted.

  As shown in FIGS. 7 and 8, the determination unit 23 obtains the crank phase angle based on the stop stroke information read from the nonvolatile memory 26 and the crank angle detected by the crank angle detection unit 21 (step S15), it is determined whether or not a predetermined startability improving condition is satisfied (step S41). The startability improvement condition is that the outside air temperature is a low temperature less than a predetermined value (for example, 10 degrees), and that the time from the previous engine stop to the current engine start is a long time that is a predetermined time or longer. And at least one of the conditions that the driver has requested to improve startability.

  If Yes in step S41, the engine control unit 24 determines the timing for increasing the fuel injection amount (step S42), and performs engine control including fuel injection control (step S43). In the present embodiment, the engine control unit 24 determines a stroke other than the intake stroke, for example, immediately after the crankshaft 5 is started, as a timing for increasing the fuel injection amount (see FIG. 8). As a result, when the startability improving condition is satisfied, the fuel injection amount per cycle increases compared to when the startability improving condition is not satisfied. As a result, it is possible to improve engine startability by increasing the fuel injection amount at an appropriate time while reducing unnecessary fuel injection by accurate stroke determination. In step S42, the timing for increasing the fuel injection amount may be the intake stroke, and the fuel injection amount in the intake stroke may be temporarily increased.

  Further, the engine control in step S43 may include a control content that the known fuel cut control is not performed instead of or in addition to the control described above, or a control content that retards the ignition timing. . By not performing fuel cut control when starting the engine, it is possible to prevent a decrease in startability, and by retarding the ignition timing when starting the engine, the air-fuel mixture is released after the inertia of the crankshaft 5 increases. The startability can be improved by burning.

(Fifth embodiment)
FIG. 9 is a flowchart for explaining a procedure of engine control when starting the engine according to the fifth embodiment. The engine control of this embodiment is a variation of the control content of step S16 (pre-combustion engine control) of the first embodiment. As shown in FIG. 9, the engine control unit 24 calculates the crank angular velocity from the information from the crank angle detection unit 21 (step S51). Next, the engine control unit 24 determines whether or not the crank angular speed is greater than a predetermined value (step S52). In the case of Yes, the engine control unit 24 performs ignition at the ignition timing (step S53). In the case of No, the engine control unit 24 does not perform ignition at the ignition timing. By doing so, it is possible to prevent the phenomenon that the crankshaft 5 is suddenly reversed at the first combustion due to the low crank angular velocity at the kick start (so-called Kickback in starting the engine). it can. Since other configurations are the same as those of the first embodiment described above, description thereof is omitted.

(Sixth embodiment)
FIG. 10 is a flowchart for explaining a procedure for recording a stop-time stroke when the engine is stopped according to the sixth embodiment. In addition, about the structure which is common in 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. Since each content of step S1-S3 and S6 of this embodiment is the same as each content of step S1-S3 and S6 of 1st Embodiment, detailed description is abbreviate | omitted. As shown in FIG. 10, the determination unit 23 estimates a crank phase angle when the rotation of the crankshaft 5 stops after the engine control unit 24 stops the engine control (step S54). In the estimation, the crank phase angle when the rotation of the crankshaft is stopped may be estimated based on the crank angular speed and the angular acceleration when the engine control is stopped in consideration of the pumping loss of the engine. Then, the determination unit 23 records the estimated crank phase angle in the non-volatile memory 26 as stop time stroke information (step S55). In this way, the power supply to the ECU 20 can be stopped without waiting for the standby time after the engine control is stopped.

(Other examples)
In addition, this invention is not limited to each embodiment mentioned above, The structure can be changed, added, or deleted. The above embodiments may be arbitrarily combined with each other. For example, some configurations or methods in one embodiment may be applied to other embodiments.

  The present invention is not limited to the apparatus and method, and may be a program for executing a stroke determination method or an engine control method. That is, the program may be stored (for example, downloaded) in a control device mounted on a vehicle that has already been sold. The present invention can be applied to all engine control devices capable of controlling the combustion state. The present invention can be applied not only to motorcycles but also to engine control devices mounted on rough terrain vehicles, utility vehicles, small planing boats, automobiles and the like. In particular, the present invention is suitably applied to an engine that is desired to improve fuel efficiency and reduce air pollutants contained in exhaust gas.

  In the above-described embodiment, a four-stroke engine is illustrated, but a two-stroke engine may be used. That is, according to the stroke discriminating method described above, it is possible to discriminate the stroke before judging the base point angle in an engine in which all strokes are completed by one rotation of the crankshaft, and the initial control at the time of engine start can be accurately performed. It can be carried out.

  The stop-time stroke information recorded in the non-volatile memory 26 may be stroke information itself instead of the crank phase angle at which the stroke can be determined. For example, the stroke information at the time of stop may be information indicating which stroke is a front rotation (crank phase angle = 0 ° or more and less than 360 °) or reverse rotation (crank phase angle = 360 ° or more and less than 720 °). Then, when the base point angle is reached, it can be determined whether the base point angle is the front rotation or the reverse rotation, and the stroke determination can be performed before the combustion stroke is reached.

  A mechanical counter may be used in place of the non-volatile memory as a structure that can store stop process information even when power is not continuously supplied. Specifically, a mechanical counter structure in which the counter structure changes with each stroke may be formed, and the counter structure may be held even if power supply is stopped. Thereby, the stop stroke can be grasped by reading the counter structure already held at the time of engine start. For example, the counter structure may be configured to mechanically hold the crank phase angle with respect to the base point angle.

  The crank angle sensor only needs to have a configuration in which a base point angle and an angle from the base point angle are obtained, and may be an angle sensor other than an electromagnetic pickup type such as a Hall IC sensor. In the above-described embodiment, the crank angle is obtained using the increment type crank angle sensor, but the crank angle may be obtained using an absolute type crank angle sensor. Specifically, in the case of a four-cycle engine, the absolute stroke angle sensor alone cannot determine the initial stroke when the crankshaft starts rotating, as with the incremental crank angle sensor. By using the process determination method, the initial process can be determined. The crank angle may be obtained using a cam angle sensor. Even with a cam angle sensor, it is not possible to accurately determine the stroke until the base point angle is detected by using the missing portion (notch) alone. However, by using the stroke discrimination method described above, the stroke is discriminated before the missing portion is detected. Appropriate control can be performed early.

  In the above-described embodiment, the stroke determination during the operation of the engine E is performed based on the intake pressure detected by the intake pressure detection unit 22, but may be performed based on a physical quantity other than the intake pressure. For example, the stroke may be determined by detecting the engine vibration when the engine vibration changes according to the stroke change. Specifically, the combustion stroke may be determined by detecting vibration generated by explosion during combustion. Further, the stroke may be determined based on the time change of the crank angular velocity. Specifically, since the change in the crank angular velocity becomes large during the combustion stroke, the time when the time change in the crank angular velocity becomes maximum may be determined as the combustion stroke. In this case, control may be performed to reduce the number of cylinders to be exploded among the plurality of cylinders so that the time change of the crank angular velocity in the combustion stroke becomes large. For example, in the case of a four-cylinder engine in which the stroke of each cylinder is shifted by 180 °, the stroke determination may be made easier by setting one of the two cylinders reaching the top dead center to an incombustible state. In addition, exhaust pressure or exhaust temperature may be used as another physical quantity that changes due to combustion.

E engine 5 crankshaft 13 fuel injector 15 ignition device 23 determination unit (determination unit)
24 Engine control unit (engine controller)
25 Recording controller (recording controller)
26 Nonvolatile memory (storage device)
27 stroke determination device 28 control device 30 power supply control device (power supply controller)

Claims (9)

A determinator for determining a stroke during operation of the engine based on at least a crank angle;
A recording controller that records in a storage device stroke information for stopping to recognize the stroke when the crankshaft stops rotating,
The determiner is
At the start of rotation of the crankshaft before combustion of the engine, a pre-combustion stroke determination is performed to determine a stroke based on the stop stroke information recorded in the storage device,
Based on a physical quantity that changes due to combustion in a cylinder of the engine, it is determined whether or not a first combustion stroke is performed in the engine after the crankshaft starts rotating,
When it is determined that the first combustion stroke has been performed, an engine stroke determination is performed to determine a post-combustion stroke to determine a stroke during operation of the engine based on a physical quantity that changes due to combustion in the cylinder of the engine. apparatus.   The determination unit determines whether or not a first combustion stroke is performed in the engine after the crankshaft starts rotating based on an intake pressure of the engine as a physical quantity that changes due to combustion in a cylinder of the engine. The engine stroke determination device according to claim 1. The engine is a four-stroke engine;
When it is detected that the intake pressure of the engine is less than a predetermined threshold value after the crankshaft starts rotating, the determination unit performs the first combustion stroke before the two strokes. The engine stroke determination device according to claim 2, wherein the engine stroke determination device is determined to have been performed. The recording controller is
When it is determined that a predetermined standby time has elapsed since the power-off command is issued, the stroke or crank phase angle when the standby time elapses is recorded in the storage device as stop stroke information, or
The engine according to any one of claims 1 to 3, wherein when it is determined that the change in the crank angle of the engine has disappeared, the latest stroke or crank angle is recorded in the storage device as the stroke information at the time of stop. Process discrimination device. The engine stroke determination device according to any one of claims 1 to 4 ,
An engine control device comprising: an engine controller that controls the engine based on a determination result of the determination device of the stroke determination device. Determining the engine controller, the crank angular speed of the engine when the engine is started is determined to be greater than the predetermined value, performing ignition at point fire timing, and the crank angular velocity when the engine is started is not greater than the predetermined value When not perform ignition at point fire timing control device for an engine according to claim 5. The engine controller increases a fuel injection amount in one cycle when a predetermined startability improving condition is satisfied, compared to when the startability improving condition is not satisfied,
The startability improvement condition is a condition that the time from the previous engine stop to the current engine start is a long time of a predetermined time or more, or an input requesting improvement of startability from the driver is made. The engine control device according to claim 5 or 6 , comprising conditions. A determination unit for determining a stroke during operation of the engine based on at least a crank angle; and a recording controller for recording stroke-time stroke information for recognizing a stroke when the crankshaft stops rotating in a storage device. A stroke discrimination device;
An engine controller that controls the engine based on a determination result of the stroke determination device,
The determiner determines a stroke when the crankshaft starts rotating based on the stop stroke information recorded in the storage device,
Determining the engine controller, the crank angular speed of the engine when the engine is started is determined to be greater than the predetermined value, performing ignition at point fire timing, and the crank angular velocity when the engine is started is not greater than the predetermined value When not perform ignition at point fire timing control device for an engine. A stroke determination step of determining a stroke during operation of the engine based on at least the crank angle;
A recording step for recording stop stroke information for recognizing a stroke when the crankshaft stops rotating, and
The determination step includes
At the start of rotation of the crankshaft before combustion of the engine, a pre-combustion stroke determination is performed to determine a stroke based on the recorded stop stroke information.
Based on a physical quantity that changes due to combustion in a cylinder of the engine, it is determined whether or not a first combustion stroke is performed in the engine after the crankshaft starts rotating,
When it is determined that the first combustion stroke has been performed, an engine stroke determination is performed to determine a post-combustion stroke to determine a stroke during operation of the engine based on a physical quantity that changes due to combustion in the cylinder of the engine. Method.

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