JP5283446B2 - FUEL INJECTION CONTROL DEVICE AND VEHICLE HAVING THE SAME - Google Patents

Description

  The present invention relates to a fuel injection control device and a vehicle driven by an engine equipped with the fuel injection device.

  The 4-cycle engine generates power by cyclically executing an intake stroke, a compression stroke, an expansion stroke (combustion stroke), and an exhaust stroke. The intake stroke is a stroke in which a mixture of fuel and air is sucked from the intake pipe toward the combustion chamber as the piston descends from the top dead center to the bottom dead center. The compression stroke is a stroke in which the piston moves from the bottom dead center to the top dead center and compresses the air-fuel mixture in the combustion chamber. The expansion stroke is a stroke in which the piston is moved to the bottom dead center by burning the air-fuel mixture in the combustion chamber. The exhaust stroke is a stroke in which the piston moves from the bottom dead center to the top dead center, and the burned gas is discharged from the combustion chamber to the exhaust pipe. By performing these strokes cyclically, the crankshaft coupled to the piston is rotationally driven.

A fuel injection device (injector) controlled by a microcomputer is disposed in the intake pipe. A controlled amount of fuel is injected from this fuel injection device at an appropriate timing during the intake stroke. As a result, the air-to-fuel ratio is controlled, and higher output, lower fuel consumption, exhaust gas cleaning, and the like are promoted.
JP 2004-162543 A

  Since the fuel injection by the fuel injection device is performed in the intake stroke, it is necessary to determine the stroke of the engine in advance. The engine stroke is determined based on, for example, the output of a crank angle sensor that detects the rotation angle of the crankshaft and the output of an intake pressure sensor that detects the pressure in the intake pipe (intake pressure). Therefore, when the engine is started, the stroke is discriminated by the crankshaft being rotated to some extent by the starter, and the fuel can be injected in synchronization with the intake stroke. The fuel injection synchronized with the intake stroke is called “synchronous injection”. For example, the patent document 1 has a description regarding control of synchronous injection.

On the other hand, when the engine is started, the temperature of the engine is low and fuel atomization is unlikely to occur. Therefore, it has been proposed to improve the startability by injecting fuel without waiting for stroke determination, evaporating the fuel in advance, and increasing the fuel ratio in the air-fuel mixture. Since such fuel injection is performed asynchronously with the intake stroke, it is called “asynchronous injection”.
In particular, in a mechanical device (for example, a transport machine) that does not include an electric starter (starter motor) and starts the engine exclusively by human power, it is desirable to improve engine startability by performing asynchronous injection. A typical example of such a mechanical device is a motorcycle.

  A motorcycle may be provided with a kick starter and may not be provided with an electric starter. The kick starter is a device that includes a kick arm that a rider kicks with a foot, and that transmits the rotational force of the kick arm to a crankshaft. When the crankshaft is rotated by the kick operation, asynchronous injection is performed accordingly, and ignition control is performed according to the output of the crank angle sensor. As a result, the engine is started. However, in order to be able to start the engine, the crankshaft needs to be rotated at a certain speed or higher.

However, the kick operation by the rider may not always produce a sufficient rotation speed of the crankshaft. For example, the top dead centering operation and the empty kick operation are applicable examples.
The top dead centering operation is an operation of rotating the crankshaft in advance until the piston gets over the top dead center. The rider slowly operates the kick arm and rotates the crankshaft to an appropriate position while feeling resistance due to compression of the combustion chamber air. If the kick operation for starting the engine is performed after the top dead centering operation, the rotational force generated by the kick operation can be efficiently transmitted to the crankshaft. If the top dead centering operation is omitted, the piston reaches the top dead center at the initial stage of the kick operation and generates a large resistance to the kick operation, so that there is a possibility that the crankshaft cannot be rotated at a sufficient rotational speed.

The empty kick operation is, for example, an operation for vaporizing the fuel in the engine and discharging it together with air when an excessive amount of fuel has entered the combustion chamber. Since the rider has no intention of starting the engine, the kick arm is operated slowly.
In addition to these operations, the rider's kick operation force may be insufficient, so that a rotational speed at which the engine can be started may not be obtained.

If asynchronous injection is performed until such a kick operation that a sufficient rotational speed for starting is not obtained, the fuel ratio in the combustion chamber becomes excessive. Therefore, there is a possibility that the engine cannot be started smoothly when the rotation speed sufficient for starting the engine is obtained by the subsequent operation.
Accordingly, an object of the present invention is to provide a fuel injection control device that can appropriately perform asynchronous injection and thereby improve the startability of the engine, and a vehicle using the same.

The fuel injection control device of the present invention is a device for controlling a fuel injection device provided in an engine. This device includes a crank angular velocity detection unit that detects a crank angular velocity of the engine, a stroke determination unit that determines a stroke of the engine, and fuel is injected from the fuel injection device in synchronization with a determination result by the stroke determination unit. The crank angular velocity detected by the crank angular velocity detection unit is greater than or equal to a predetermined angular velocity threshold when the fuel injection device is ready to be driven before the stroke determination by the synchronous injection control unit and the stroke determination unit is completed. A determination unit for determining whether or not the crank angular velocity is greater than or equal to a predetermined angular velocity threshold by the determination unit, the fuel is injected without waiting for the stroke determination by the stroke determination unit, When it is determined that the crank angular speed is less than the predetermined angular speed threshold, And a asynchronous injection control unit for controlling the fuel injection device so as to prohibit stroke determination prior to fuel injection by the stroke determination unit.

According to this configuration, the fuel injection (asynchronous injection) performed without waiting for the stroke determination is executed when the crank angular velocity is equal to or higher than the predetermined angular velocity threshold . That is, the asynchronous injection before the engine stroke is determined, that is, at the time of starting, is prohibited when the crank angular velocity is less than the predetermined angular velocity threshold . As a result, it is possible to prohibit asynchronous injection from being performed when a kick operation that does not provide a sufficient rotational speed for starting, such as top dead center operation or empty kick operation, is performed, and excessive fuel is supplied to the engine. Supplying can be suppressed. As a result, the inside of the engine can be maintained in an appropriate state, so that the engine can be reliably started at a crank angular speed at which the engine can be started. Thus, the startability of the engine is improved.

  After the engine is started, the stroke determination unit can determine the stroke of the engine, and thereafter, synchronous injection is performed according to the stroke determination result.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic side view showing a configuration of a motorcycle according to an embodiment of the present invention. The motorcycle 1 includes a body frame 2, an engine 3, a front wheel 4, and a rear wheel 5. An engine 3 is mounted on the body frame 2. A head pipe 6 is provided at the front portion of the vehicle body frame 2. A front fork 7 is supported on the head pipe 6 so as to be swingable in the left-right direction. A front wheel 4 is pivotally supported at the lower end of the front fork 7. A rear arm 8 is supported at the rear portion of the vehicle body frame 2. The rear wheel 5 is supported on the rear end portion of the rear arm 8.

  A handle 10 for steering the motorcycle 1 is fixed to the upper end of the front fork 7. At both ends of the handle 10, a pair of grips that the rider holds with left and right hands are provided. One of them (usually the right grip) is an accelerator grip 11 that is rotated around the handle shaft by the rider. The rider can adjust the rotational speed of the engine 3 by operating the accelerator grip 11.

The engine 3 is, for example, a 4-cycle single cylinder engine. The engine 3 has a crankcase 15 in which a crankshaft is accommodated in the lower part. A cylinder block 16 is coupled to a front portion on the crankcase 15. A cylinder head 17 is fixed on the cylinder block 16.
A transmission mechanism (not shown) is built in the crankcase 15. A chain 19 is wound around the output shaft of the transmission mechanism and a sprocket 18 fixed to the rear wheel 5. As a result, the driving force of the engine 3 is transmitted to the rear wheel 5 via the speed change mechanism and the chain 19. These constitute a transmission mechanism for transmitting the driving force of the engine 3 to the wheels.

A fuel tank 20 is disposed above the engine 3 and supported by the vehicle body frame 2. A seat 21 is disposed behind the fuel tank 20. An electronic control unit (ECU) 22 as a control device is provided below the seat 21.
An exhaust port is opened in the front wall of the cylinder head 17 of the engine 3. An exhaust pipe 23 is connected to the exhaust port. The exhaust pipe 23 is bent rearward and is connected to a muffler 24 disposed on the side of the rear wheel 5.

An intake port is opened in the rear wall of the cylinder head 17. An intake pipe 42 is connected to the intake port.
A kick arm 9 for starting the engine 3 by a rider's kick operation is provided on the right side in the traveling direction of the motorcycle 1. The kick arm 9 is coupled to a starting device housed in the crankcase 15. The starter is configured to transmit the rotation to the crankshaft and cause the crankshaft to rotate when the kick arm 9 is rotated by being kicked by the rider's foot.

  FIG. 2 is a diagram for explaining a configuration related to the engine 3. The engine 3 includes a crankcase 15, a cylinder block 16 communicating with the crankcase 15, a cylinder head 17 coupled to the head of the cylinder block 16, and a piston 26 accommodated in the cylinder block 16. Yes. A crankshaft 27 is rotatably accommodated in the crankcase 15. A piston 26 is coupled to the crankshaft 27 via a connecting rod 28. Thus, the vertical movement of the piston 26 is transmitted to the crankshaft 27 via the connecting rod 28 and is converted into rotation of the crankshaft 27.

  An intake pipe 42 and an exhaust pipe 23 are coupled to the cylinder head 17, and these communicate with a combustion chamber 43 above the piston 26. An intake valve 31 and an exhaust valve 32 for opening and closing the intake pipe 42 and the exhaust pipe 23 and the combustion chamber 43 are arranged at the connecting portion. The intake valve 31 and the exhaust valve 32 are opened and closed at predetermined timings by cams 33 and 34 that are driven in synchronization with the rotation of the crankshaft 27. A spark plug 44 is further attached to the cylinder head 17, and a discharge portion of the spark plug 44 is located in the combustion chamber 43. A discharge voltage is applied to the spark plug 44 from the ignition coil 45.

  In the middle of the intake pipe 42, an injector 40 (fuel injection device) is attached. The fuel stored in the fuel tank 20 is supplied to the injector 40 by a fuel pump 47. A throttle valve 46 is interposed in the intake pipe 42. Further, an intake pressure sensor 53 for detecting an intake pressure between the throttle valve 46 and the intake valve 31 is attached to the intake pipe 42. The throttle valve 46 is a device for adjusting the amount of intake air to the engine 3 by changing the opening degree of the intake passage (throttle opening degree) according to the accelerator operation of the rider. The throttle valve 46 is disposed upstream of the injector 40 in the intake air inflow direction. The intake pressure sensor 53 is disposed between the throttle valve 46 and the injector 40 and detects the atmospheric pressure in the intake pipe 42.

  Further, a crank angle sensor 55 is attached to the crankcase 15. The crank angle sensor 55 detects the rotation angle of the crankshaft 27. On the outer peripheral portion of the crankshaft 27, protrusion-like detection teeth 30 are provided at positions obtained by dividing the entire circumference at equal intervals, except for one location. Of the plurality of positions divided at equal intervals, a position where the detection tooth 30 is not provided is called a “missing tooth position” and is denoted by reference numeral 30a. In the case of dividing into 12 parts, the adjacent detection teeth 30 (or missing tooth positions 30a) are arranged at an interval of 30 degrees with respect to the rotation angle of the crankshaft 27. The crank angle sensor 55 generates output signals of different levels in a period in which the detection teeth 30 are opposed and a period in which the detection teeth 30 are not opposed. This is a crank pulse. Therefore, the rotation angle of the crankshaft 27 can be detected by counting crank pulses with the missing tooth position 30a as a reference position. By using this rotation angle, the stroke of the engine 3 can be determined.

The output signals of the above sensors are given to the electronic control unit 22 (see FIG. 1). The electronic control unit 22 executes control of the ignition coil 45 (ignition control), control of the injector 40 (fuel injection control), and control of the fuel pump 47 (fuel supply control).
FIG. 3 is a block diagram for explaining the configuration and function of the electronic control unit 22. The electronic control unit 22 includes a microcomputer 60, a pulse processing unit 61 that processes an output signal of the crank angle sensor 55, an ignition drive circuit 62 for the ignition coil 45, an injector drive circuit 63 for the injector 40, And a pump drive circuit 64 for the fuel pump 47. The microcomputer 60 includes a CPU, a ROM, and other necessary memories and interfaces, and operates as a plurality of function processing units by executing a predetermined program. More specifically, the microcomputer 60 has a function as a rotation angle calculation unit 70, a function as a crank angular velocity calculation unit 71, a function as a stroke determination unit 72, and a function as an injection control unit 73. doing. The function as the injection control unit 73 includes a function as the synchronous injection control unit 73A and a function as the asynchronous injection control unit 73B.

  The pulse processing unit 61 shapes the output signal of the crank angle sensor 55 and generates a crank pulse having the waveform shaped. The crank pulse after waveform shaping has, for example, a high level during a period when the crank angle sensor 55 faces the detection tooth 30 and a low level during a period when the crank angle sensor 55 does not face the detection tooth 30. Is a signal having The crank pulse includes a short pulse corresponding to the detection tooth 30 and a long pulse corresponding to the missing tooth position 30a. A long pulse is a pulse having a longer pulse width than a short pulse.

  The function of the rotation angle calculation unit 70 is to generate information representing the rotation angle of the crankshaft 27 based on the crank pulse processed by the pulse processing unit 61. More specifically, a long pulse corresponding to the missing tooth position 30a is detected. A crank pulse number “0” is generated as information representing the rotation angle of the crankshaft 27 in synchronization with the long pulse (more specifically, for example, the falling edge of the pulse). The crank pulse number “0” represents that the rotation angle of the crankshaft 27 is the reference rotation angle (reference position). At this time, for example, the piston 26 is located at the bottom dead center. Thereafter, each time a short pulse is input, the rotation angle calculation unit 70 sequentially increments the crank by “+1” in synchronization with the short pulse (more specifically, for example, the fall of the pulse). Pulse numbers 1, 2, 3,... Are generated. Therefore, the crank pulse number corresponds to the rotation angle of the crankshaft 27. The crank pulse number is used to execute each function of the stroke determination unit 72 and the injection control unit 73 as information representing the rotation angle.

  The function of the crank angular velocity calculation unit 71 is to calculate the rotational angular velocity of the crankshaft 27 based on the crank pulse generated from the pulse processing unit 61. More specifically, the function of the crank angular velocity calculation unit 71 includes a function as a time counting unit 77 and a function as an average interval calculation unit 78. The function of the timing unit 77 is to measure the interval between adjacent crank pulses. The function of the average interval calculation unit 78 is an average value (hereinafter referred to as “average pulse interval”) of a predetermined number (for example, 3 to 4) of crank pulse intervals (however continuous in time) measured by the time measuring unit 77. Is calculated). This average pulse interval is inversely proportional to the rotational angular velocity (crank angular velocity) of the crankshaft 27. Therefore, the average pulse interval can be used as an index representing the crank angular velocity.

Although the crank pulse is a long pulse at the missing tooth position 30a of the crankshaft 27, the influence of the missing tooth position 30a can be alleviated by taking an average value of a plurality of crank pulse intervals. That is, the average pulse interval corresponds to the rotational angular velocity of the crankshaft 27 with sufficient accuracy necessary for control of the engine 3 regardless of the presence of the missing tooth position 30a.
The crank pulse interval is, for example, the time from the fall of the crank pulse to the next fall. Of course, the time from the falling edge of the crank pulse to the next rising edge may be measured as the crank pulse interval. Similarly, the time from the rise of the crank pulse to the next rise may be measured as the crank pulse interval. Furthermore, the time from the rise of the crank pulse to the next fall may be measured as the crank pulse interval.

  The function of the stroke determination unit 72 is based on the crank pulse number (that is, the rotation angle of the crankshaft 27) obtained by the operation of the rotation angle calculation unit 70 and the intake pressure detected by the intake pressure sensor 53. It is to determine the process. More specifically, the stroke determination unit 72 acquires a crank pulse number generated by the rotation angle calculation unit 70. On the other hand, the stroke determination unit 72 determines the intake stroke by monitoring the decrease in the air pressure (intake pressure) in the intake pipe 42 based on the output from the intake pressure sensor 53. The stroke determination unit 72 determines the stroke of the engine 3 based on the crank pulse number and the determination result of the intake stroke.

  The synchronous injection control unit 73A specifies the rotation angle of the crankshaft 27 by acquiring the crank pulse number generated by the rotation angle calculation unit 70. Further, the synchronous injection control unit 73A acquires the determination result by the stroke determination unit 72. Then, the synchronous injection control unit 73A drives the injector 40 at an appropriate timing set based on the stroke determination result and the rotation angle of the crankshaft 27. More specifically, the synchronous injection control unit 73A drives the injector 40 at a timing when a predetermined crank pulse number is generated (a timing when the crankshaft 27 reaches a predetermined rotation angle). The drive of the injector 40 may be performed in an exhaust stroke or may be performed in an intake process. The fuel injection performed when the synchronous injection control unit 73A drives the injector 40 based on the stroke determination result is referred to as “synchronous injection”.

  Asynchronous injection control unit 73B is mainly responsible for controlling injector 40 in a period before the stroke is determined by stroke determination unit 72 (ie, a period immediately after startup). The asynchronous injection control unit 73B controls the injector 40 based on the crank pulse number generated by the rotation angle calculation unit 70 and the average pulse interval (information corresponding to the crank angular speed) calculated by the crank angular speed calculation unit 71. .

More specifically, the asynchronous injection control unit 73B injects fuel from the injector 40 without waiting for completion of stroke determination when the rider kicks the kick arm 9 (see FIG. 1) and starts the engine 3. Let Such fuel injection is called “asynchronous injection”.
FIG. 4 is a flowchart for explaining characteristic processing relating to fuel injection control. This process is executed in synchronization with the crank pulse.

  First, it is determined whether or not the stroke determination by the stroke determination unit 72 has been completed (step S1). If the stroke determination has been completed (step S1: YES), synchronous injection control for controlling the injector 40 is performed by the synchronous injection control unit 73A. That is, it is determined whether it is the fuel injection timing based on the stroke determination result by the stroke determination unit 72 and the crank pulse number generated by the rotation angle calculation unit 70 (step S2). If it is the fuel injection timing (step S2: YES), the fuel injection coefficient Tinj is set to “1” (step S3). On the other hand, when it is determined that it is not the fuel injection timing (step S2: NO), the fuel injection coefficient Tinj is set to “0” (step S4). Then, the injector 40 is driven by the injector drive circuit 63 in accordance with the fuel injection coefficient Tinj (step S5). If the fuel injection coefficient Tinj is “1”, the injector 40 is actually driven to inject fuel. On the other hand, if the fuel injection coefficient Tinj is “0”, the injector 40 is not actually driven and fuel injection is not performed.

  On the other hand, in the period before the stroke determination (step S1: NO), asynchronous injection control for controlling the injector 40 by the asynchronous injection control unit 73B is performed. More specifically, first, the crank angular velocity calculation unit 71 determines whether or not a predetermined number (for example, 2 to 3) of crank pulses have been input (step S6). If the specified number of crank pulses is not input, the subsequent processing is not performed. When a predetermined number of crank pulses are input (step S6: YES), an average value Tav of intervals between the predetermined number of crank pulses (hereinafter referred to as “average pulse interval Tav”) is calculated (step S7: crank). Function of angular velocity calculation unit 71). Then, it is determined whether or not the average pulse interval Tav is equal to or smaller than a predetermined threshold (that is, whether or not the crank angular velocity is equal to or larger than a predetermined angular velocity threshold) (step S8). If the average pulse interval Tav is less than or equal to the threshold value, it is determined that the crankshaft 27 is rotating at a rotational angular speed sufficient to start the engine 3, and the fuel injection coefficient Tinj is set to “1” (step S9). ). On the other hand, when the average pulse interval Tav is less than the threshold (step S8: NO), it is determined that the crankshaft 27 is not rotating at such a high speed that the engine 3 can be started. The injection coefficient Tinj is set to “0” (step S10). Then, based on the set fuel injection coefficient Tinj, the injector 40 is controlled (step S5).

  Thus, when the engine 3 is started, if the crank angular velocity is sufficiently large (step S8: YES), asynchronous injection for injecting fuel is executed regardless of the stroke determination (steps S9, S5). The timing of the asynchronous injection is preferably the timing at which the piston 26 is moving from the bottom dead center to the top dead center when the rotation angle calculation unit 70 generates a crank pulse number. If 70 is before generating the crank pulse number, the fuel may be injected asynchronously at an arbitrary timing.

On the other hand, when the crank angular velocity is insufficient (step S8: NO), asynchronous injection is prohibited (step S10). Therefore, when the crankshaft 27 is rotated at such a low speed that it is difficult to start the engine 3, it is possible to avoid making the inside of the engine 3 excessively fuely due to unnecessary fuel injection.
FIG. 5 is a waveform diagram for explaining an operation example at the time of engine start. 5 (a) shows the stroke of the engine, FIG. 5 (b) shows the crank pulse, FIG. 5 (c) shows the intake pressure, FIG. 5 (d) shows the injection operation by the injector 40, FIG. (e) represents an ignition operation by the spark plug 44.

  The rotation angle calculation unit 70 monitors the crank pulse. When a long pulse corresponding to the missing tooth position 30a is input, the rotation angle calculation unit 70 generates a crank pulse number “0” at the falling timing. Thereafter, each time the crank pulse falls, the rotation angle calculation unit 70 increments the crank pulse number by “+1”. Then, when a long pulse corresponding to the missing tooth position 30a is input, the rotation angle calculation unit 70 initializes the crank pulse number to “0”. However, after the stroke determination by the stroke determination unit 72 is completed, the crank pulse number is not initialized when the long pulse falls immediately before the exhaust stroke. That is, after the stroke determination is completed, the crank pulse number is initialized to “0” only when the long pulse falls immediately before the compression stroke. Therefore, after the stroke is determined, the crank pulse number becomes information representing not only the rotation angle of the crankshaft 27 but also the stroke of the engine 3.

  In the intake stroke, the intake valve 31 is opened and the piston 26 reaches from the top dead center to the bottom dead center. Therefore, the intake pressure (atmospheric pressure in the intake pipe 42) decreases. On the other hand, when the piston 26 is at the bottom dead center, the missing tooth position 30 a faces the crank angle sensor 55. Therefore, the stroke determination unit 72 monitors the decrease in the intake pressure based on the output of the intake pressure sensor 53. When the long pulse corresponding to the missing tooth position 30a is input during the period in which the decrease in the intake pressure is detected, the stroke determination unit 72 determines that the compression stroke starts following the long pulse. Thereby, the stroke determination is completed. Thereafter, the stroke determination unit 72 determines which stroke the engine 3 is in by counting the crank pulses.

  Synchronous injection performed after completion of stroke determination is performed based on the crank pulse number. That is, when the crank pulse number corresponding to the middle stage of the exhaust stroke is generated, the injector 40 is driven and fuel is injected accordingly. Further, the ignition control after the stroke determination is also performed based on the crank pulse number. In other words, when a crank pulse number corresponding to the end of the compression stroke is generated, the spark plug 44 is driven accordingly. Thereby, the air-fuel mixture in the combustion chamber 43 is ignited and burned.

  The crank pulse number cannot be generated in the period immediately after the start of the kick arm 9 by the kick operation. During this period, an average pulse interval Tav is calculated by the crank angular velocity calculation unit 71, and this average pulse interval Tav is compared with the aforementioned threshold value. When the average pulse interval Tav becomes equal to or less than the threshold value, the injector 40 is driven and asynchronous injection (starting asynchronous injection) is performed. When the average pulse interval Tav exceeds the threshold value and the crank angular speed is insufficient for starting the engine 3, asynchronous injection is prohibited in order to prevent excessive fuel in the cylinder.

  When a long pulse corresponding to the missing tooth position 30a is input, the reference position (reference rotation angle) of the crankshaft 27 can be determined, and thereafter, a crank pulse number is generated. Therefore, the injector 40 injects fuel at a timing near the middle of the period in which the piston 26 moves from the bottom dead center to the top dead center (asynchronous injection). On the other hand, the ignition control is started after the generation of the crank pulse number is started. That is, the spark plug 44 is driven at the end of the period in which the piston 26 moves from the bottom dead center to the top dead center (immediately after asynchronous injection).

  As described above, according to this embodiment, asynchronous injection is prohibited when the average pulse interval Tav exceeds the predetermined threshold value and the crank angular velocity is insufficient to start the engine 3. Therefore, when an operation that causes the crankshaft 27 to rotate slowly, such as a top dead centering operation or an empty kick operation, asynchronous injection is not performed. When the average pulse interval Tav is equal to or less than the threshold value and the crank angular speed is sufficient to start the engine 3, asynchronous injection is performed, and the start of the engine 3 is promoted. Thus, unnecessary asynchronous injection is prohibited, while asynchronous injection can be reliably performed when the crankshaft 27 is rotated at a speed at which the engine 3 can be started. Thereby, the startability of the engine 3 can be remarkably improved. As a result, the motorcycle 1 can be started smoothly.

  In addition, since the crank angular velocity is evaluated using the average pulse interval Tav instead of one pulse interval, it can be appropriately determined whether or not asynchronous injection should be performed. That is, the crank angular speed at the initial stage of the kick operation does not differ much between the top dead center operation and the kick operation for starting the engine. Therefore, it is not possible to properly determine whether or not asynchronous injection is possible with only one pulse interval. Further, as described above, at the missing tooth position 30a, the pulse interval becomes long even when a kick operation for starting the engine is performed. Therefore, in this embodiment, the determination of whether or not asynchronous injection is possible is optimized by using the average pulse interval Tav.

  As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, in the above-described embodiment, the example in which the engine is started by the kick starter has been described. However, the present invention can be applied to a mechanical device that can start the engine by human power in addition to the kick starter. It is. For example, when the engine of a motorcycle is started by so-called pushing, the engine startability can be improved by performing the same control as described above. In addition, the present invention can be widely applied to mechanical devices that can start an engine by an operation by human power in a vehicle other than a motorcycle, and also in a mechanical device other than a vehicle. The engine is not limited to a single cylinder engine, and may be a multi-cylinder engine. In addition, various design changes can be made within the scope of matters described in the claims.

The characteristics to be understood from the description of this specification are described below.
1. A fuel injection control device for controlling a fuel injection device provided in an engine, comprising: a crank angular velocity detection unit for detecting a crank angular velocity of the engine; a stroke determination unit for determining a stroke of the engine; and a stroke determination unit Synchronous injection control unit for injecting fuel from the fuel injection device in synchronization with the determination result, and stroke determination by the stroke determination unit when the crank angular velocity detected by the crank angular velocity detection unit satisfies a predetermined asynchronous injection condition An asynchronous injection control unit that controls the fuel injection device so as to prohibit fuel injection before stroke determination by the stroke determination unit if the crank angular velocity does not satisfy the asynchronous injection condition. A fuel injection control device.

  According to this configuration, fuel injection (asynchronous injection) that is performed without waiting for stroke determination is executed on condition that the crank angular velocity satisfies a predetermined asynchronous injection condition. That is, before the engine stroke is determined, that is, at the time of starting, asynchronous injection is prohibited when the crank angular velocity does not satisfy the asynchronous injection condition. As a result, the asynchronous injection is appropriately controlled when the engine is started. Therefore, when the crank angular velocity is insufficient for starting the engine, asynchronous injection can be prohibited, and supply of excess fuel to the engine can be suppressed. As a result, the inside of the engine can be maintained in an appropriate state, so that the engine can be reliably started at a crank angular speed at which the engine can be started. Thus, the startability of the engine is improved.

After the engine is started, the stroke determination unit can determine the stroke of the engine, and thereafter, synchronous injection is performed according to the stroke determination result.
2. 2. The fuel injection device according to claim 1, wherein the crank angular velocity detection unit includes a crank angle sensor that generates a crank pulse at a time interval inversely proportional to the rotational speed of the crankshaft, and an interval between crank pulses generated by the crank angle sensor. The asynchronous injection control unit, based on the time measurement result of the time measurement unit, the asynchronous injection condition that the average value of a plurality of consecutive crank pulse intervals is equal to or less than a predetermined threshold, A fuel injection control device for controlling the fuel injection device.

  According to this configuration, the time interval of the crank pulse generated by the rotation angle sensor is measured. In this case, the crank angular velocity is inversely proportional to the time interval of the crank pulse. On the other hand, the asynchronous injection condition is that the average value of successive crank pulse intervals is not more than a predetermined threshold value. As a result, asynchronous injection is permitted when the crank angular velocity is equal to or greater than the predetermined angular velocity threshold, and otherwise asynchronous injection is prohibited.

When the starting operation for rotating the crankshaft is performed manually, the crank angular velocity at the initial stage of operation is small. Therefore, it is impossible to determine whether the engine can be started only by the time interval between the pair of crank pulses.
The rotation angle sensor is a signal having a waveform different from that at other rotation angles at a specific rotation angle (for example, the rotation angle corresponding to the bottom dead center of the piston) in order to specify the rotation angle of the crankshaft. Is often configured to generate For example, the rotation angle sensor is configured not to generate a pulse at a specific rotation angle or to generate a pulse having a different pulse width at the specific rotation angle. In this case, an accurate crank angular velocity cannot be obtained only by the interval between the pair of crank pulses.

Therefore, it is preferable to determine whether or not asynchronous injection should be performed based on an average value of a plurality of continuous crank pulse intervals. As a result, it is possible to perform asynchronous injection after reliably determining that the crank angular speed at which the engine can be started has been reached. As a result, the asynchronous injection before the stroke determination can be performed more appropriately, and the engine startability can be further improved.
3. A vehicle comprising: an engine including a fuel injection device; a transmission mechanism that transmits a driving force of the engine to wheels; and the fuel injection control device according to item 1 or 2 that controls the fuel injection device. With this configuration, asynchronous injection before stroke determination is appropriately controlled. As a result, engine startability is improved, so that the vehicle can be brought into a state where it can start smoothly.

1 is an illustrative side view showing a configuration of a motorcycle according to an embodiment of the present invention. It is a figure for demonstrating the structure relevant to an engine. It is a block diagram for demonstrating the structure and function of an electronic control unit. It is a flowchart for demonstrating the characteristic process regarding fuel-injection control. It is a wave form chart for explaining an example of operation at the time of engine starting.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motorcycle 3 Engine 4 Front wheel 5 Rear wheel 9 Kick arm 22 Electronic control unit 27 Crankshaft 30 Detection tooth 30a Missing tooth position 40 Injector (fuel injection device)
53 Intake pressure sensor 55 Crank angle sensor (Crank angular velocity detection unit)
60 Microcomputer 61 Pulse Processing Unit 63 Injector Drive Circuit 70 Rotation Angle Calculation Unit 71 Crank Angular Speed Calculation Unit (Crank Angular Speed Detection Unit)
72 stroke discrimination unit 73 injection control unit (fuel injection control device)
73A Synchronous injection control unit 73B Asynchronous injection control unit 77 Timing unit 78 Average interval calculation unit Tav Average pulse interval Tinj Fuel injection coefficient

Claims (4)

A fuel injection control device for controlling a fuel injection device provided in an engine,
A crank angular velocity detection unit for detecting the crank angular velocity of the engine;
A stroke determination unit for determining the stroke of the engine;
A synchronous injection control unit that injects fuel from the fuel injection device in synchronization with a determination result by the stroke determination unit;
Whether or not the crank angular velocity detected by the crank angular velocity detection unit is equal to or greater than a predetermined angular velocity threshold when the fuel injection device is in a drivable state before the stroke determination by the stroke determination unit is completed. A discriminating unit for discriminating;
When it is determined by the determination unit that the crank angular velocity is equal to or greater than a predetermined angular velocity threshold, fuel is injected without waiting for a stroke determination by the stroke determination unit, and it is determined that the crank angular velocity is less than a predetermined angular velocity threshold. And an asynchronous injection control unit that controls the fuel injection device so as to prohibit the fuel injection before the stroke determination by the stroke determination unit. The crank angular velocity detection unit includes a crank angle sensor that generates a crank pulse at a time interval inversely proportional to the rotational speed of the crankshaft, and a timing unit that measures the interval of the crank pulse generated by the crank angle sensor,
The discriminating unit discriminates whether or not an average value of a plurality of continuous crank pulse intervals is equal to or less than a predetermined threshold based on a timing result of the timing unit, so that the crank angular velocity is equal to or higher than a predetermined angular velocity threshold. The fuel injection control device according to claim 1, wherein it is determined whether or not there is. An engine with a fuel injection device;
A transmission mechanism for transmitting the driving force of the engine to the wheels;
A crank angular velocity detection unit for detecting the crank angular velocity of the engine;
A stroke determination unit for determining the stroke of the engine;
A synchronous injection control unit that injects fuel from the fuel injection device in synchronization with a determination result by the stroke determination unit;
Whether or not the crank angular velocity detected by the crank angular velocity detection unit is equal to or greater than a predetermined angular velocity threshold when the fuel injection device is in a drivable state before the stroke determination by the stroke determination unit is completed. A discriminating unit for discriminating;
When it is determined by the determination unit that the crank angular velocity is equal to or greater than a predetermined angular velocity threshold, fuel is injected without waiting for a stroke determination by the stroke determination unit, and it is determined that the crank angular velocity is less than a predetermined angular velocity threshold. A vehicle including an asynchronous injection control unit that controls the fuel injection device to prohibit the fuel injection before the stroke determination in the stroke determination unit. The crank angular velocity detection unit includes a crank angle sensor that generates a crank pulse at a time interval inversely proportional to the rotational speed of the crankshaft, and a timing unit that measures the interval of the crank pulse generated by the crank angle sensor,
The discriminating unit discriminates whether or not an average value of a plurality of continuous crank pulse intervals is equal to or less than a predetermined threshold based on a timing result of the timing unit, so that the crank angular velocity is equal to or higher than a predetermined angular velocity threshold. The vehicle according to claim 3, wherein it is determined whether or not there is.

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