JP7490482B2 - Fuel injection method and fuel injection device - Google Patents

Description

The present invention relates to a fuel injection method and a fuel injection device, and in particular to a fuel injection method and a fuel injection device used when starting an engine with a kick starter.

Conventionally, vehicles that do not have an on-board battery are known to be equipped with a kick starter that starts the engine by manually rotating the crankshaft. When starting the engine with a kick starter, the operation of the kick starter rotates a generator directly connected to the crankshaft, and the generated power is used to complete the initial processing of the ECU (engine control unit) and the fuel injection device, making it possible to execute fuel injection control.

Patent document 1 discloses a technology that shortens the time it takes for the initial processing when the ECU starts up. If the time it takes for the initial processing is shortened, the time it takes for the engine to start can be shortened.

JP 2008-223730 A

However, in Patent Document 1, it is assumed that fuel injection control will start after the initial processing of the ECU and the initial processing of the fuel injection device are completed, and there is no consideration of starting fuel injection control before the initial processing of the fuel injection device is completed.

The object of the present invention is to provide a fuel injection method and a fuel injection device that solves the problems of the conventional technology and can shorten the time it takes for the engine to start when starting the engine with a kick starter.

To achieve the above object, the present invention provides a fuel injection method applied to an engine starting device (100) including a kick starter (30) for manually rotating the crankshaft (S) of an engine (E), a generator (50) that rotates synchronously with the crankshaft (S), a crank angle sensor (40), a fuel injection device (90) that injects fuel pumped from a fuel pump (93), and a control device (80) that controls the fuel injection device (90), the first feature of which is that fuel injection is performed during the initial processing of the fuel pump (93).

The second feature is that the fuel injection time (TOUT) during the initial processing of the fuel pump (93) is longer than during normal injection after the initial processing.

The third feature is that fuel injection is performed during the initial processing of the fuel pump (93) and during the initial processing of the control device (80).

The fourth feature is that the time from the start of the control device (80) to the first fuel injection is counted, and the shorter the time, the longer the fuel injection time, while the longer the time, the closer the fuel injection time becomes to normal injection.

The fifth feature of the engine starting device (100) is that it includes a rotation speed calculation means (81) that calculates the rotation speed of the engine (E), and when the rotation speed calculated by the rotation speed calculation means (81) is less than a threshold value, the fuel injection time is made longer than that during normal injection.

Furthermore, in a fuel injection device having an engine starting device (100) including a kick starter (30) for manually rotating the crankshaft (S) of the engine (E), a generator (50) that rotates synchronously with the crankshaft (S), a crank angle sensor (40), a fuel injection device (90) that injects fuel pumped from a fuel pump (93), and a control device (80) that controls the fuel injection device (90), a sixth feature is that the control device (80) injects fuel during the initial processing of the fuel pump (93).

According to the first feature, in a fuel injection method applied to an engine starting device (100) including a kick starter (30) for manually rotating the crankshaft (S) of an engine (E), a generator (50) that rotates synchronously with the crankshaft (S), a crank angle sensor (40), a fuel injection device (90) that injects fuel pumped from a fuel pump (93), and a control device (80) that controls the fuel injection device (90), fuel is injected during the initial processing of the fuel pump (93), thereby making it possible to speed up the start of the engine.

According to the second feature, the fuel injection time (TOUT) during the initial processing of the fuel pump (93) is longer than the normal injection time after the initial processing, so that the fuel injection amount can be made closer to the amount of fuel injected when the initial processing is completed.

According to the third feature, fuel injection is performed during the initial processing of the fuel pump (93) and the initial processing of the control device (80), making it possible to speed up the start of the engine.

According to the fourth feature, the time from the start of the control device (80) to the first fuel injection is counted, and the shorter the time, the longer the fuel injection time becomes, while the longer the time, the closer the fuel injection time becomes to normal injection, so that the amount of fuel injection can be adjusted appropriately according to the pump pressure rise situation.

According to a fifth feature, the engine starting device (100) includes a rotation speed calculation means (81) that calculates the rotation speed of the engine (E), and when the rotation speed calculated by the rotation speed calculation means (81) is less than a threshold value, the fuel injection time is made longer than during normal injection, so that when starting is performed using a kick starter, the fuel injection time is made longer, thereby improving the startability of the engine.

According to the sixth feature, in a fuel injection device having an engine starting device (100) including a kick starter (30) for manually rotating the crankshaft (S) of an engine (E), a generator (50) that rotates synchronously with the crankshaft (S), a crank angle sensor (40), a fuel injection device (90) that injects fuel pumped from a fuel pump (93), and a control device (80) that controls the fuel injection device (90), the control device (80) injects fuel during the initial processing of the fuel pump (93), thereby making it possible to speed up the start of the engine.

1 is a right side view of a motorcycle according to an embodiment of the present invention. 1 is a block diagram showing an overall configuration of an engine starting device according to an embodiment of the present invention; 4 is a time chart showing a driving state of a fuel injection device at the time of starting the engine. 4 is a flowchart showing a procedure of initial injection control. 4 is a time chart showing a driving state of an ignition device when the engine is started. 4 is a flowchart showing a procedure of fixed ignition control. FIG. 11 is an explanatory diagram showing a method for determining whether or not there is a tooth missing section based on a crank pulse.

The preferred embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a right side view of a motorcycle 1 according to one embodiment of the present invention. Motorcycle 1 is a sports-type saddle-ride vehicle that transmits the rotational power of an engine E, which is the power source of a power unit P, to a rear wheel WR via a stepped transmission housed in a crankcase 12.

A head pipe 6 that pivotally supports the steering mechanism of the front wheel WF is provided at the front end of the main frame 4 that constitutes the body frame 3. The front wheel WF is pivotally supported at the lower end of a pair of left and right front forks 7 that constitute the steering mechanism. A handlebar 5 that steers the steering mechanism is attached to the upper part of the front forks 7.

A hanger frame 9 that supports the front side of the crankcase 12 of the power unit P is connected to a position near the bottom of the head pipe 6, and a plate-shaped reinforcing gusset 8 is suspended between the main frame 4 and the hanger frame 9. A pair of left and right pivot plates 13 are fixed to the lower end of the main frame 4, which extends rearward from the head pipe 6 and curves downward, and is provided with pivots 28 that pivotally support the front end of a swing arm 17 so that it can swing freely. The swing arm 17, which pivotally supports the rear wheel WR so that it can rotate freely, is suspended from the main frame 4 by a rear cushion 18.

The power unit P, which is an integral combination of a four-stroke single-cylinder engine E and a stepped transmission, is supported by a pivot plate 13 and a hanger frame 9. A throttle body 26 having a fuel injection device 25 is fixed to the rear of the cylinder head 10 of the engine E, and an air cleaner box 21 is connected to the rear of the throttle body 26. Meanwhile, an exhaust pipe 11 that directs combustion gas to a muffler 19 at the rear of the vehicle body is connected to the front of the cylinder head 10. An ACG 50 that functions as a generator after the engine E is started is provided at the end of the crankshaft S of the engine E. A kick starter 30 is provided on the crankcase 12 for manually cranking the crankshaft S.

A fuel tank 2 with a bottom shape that straddles the main frame 4 in the vehicle width direction is disposed above the power unit P. A rear frame 20 that supports a seat 22 and the like is fixed to the rear of the main frame 4, and an ECU 80 serving as a control device is disposed at the upper rear end of the rear frame 20.

Figure 2 is a block diagram showing the overall configuration of the engine starting device 100 according to this embodiment. The ECU 80 includes a rotation speed calculation means 81 that calculates the rotation speed Ne of the engine E, an initial processing means 82, a fuel injection device drive means 83, and an ignition device drive means 84.

The ACG 50 is fixed to the crankshaft S. The rotational position of the crankshaft S is detected by a crank angle sensor 40. The crank angle sensor 40 consists of a pulse rotor 42 attached to the end of the crankshaft S, and a pulse generator 41 that detects the passage of pulse teeth 43 provided on the pulse rotor 42 and emits a pulse signal. The ten pulse teeth 43 are provided at 30 degree intervals around the circumference of the circular pulse rotor 42, excluding the toothless section 44.

The rotation speed calculation means 81 calculates the rotation speed Ne of the crankshaft S based on the output of the crank angle sensor 40. The motorcycle 1 according to this embodiment does not have an on-board battery, and the engine E is started by the kick starter 30. When the ignition switch 92 is switched on and the kick starter 30 is operated, the ACG 50 rotates and power generation begins. When the power generated by the ACG 50 is supplied to the initial processing means 82, the initial processing begins for the ECU 80 and the fuel pump 93 as a preparation for driving. The fuel injection device driving means 83 begins the initial driving of the fuel injection device 90 in response to a command from the initial processing means 82. Also, the ignition device driving means 84 begins the initial driving of the ignition device 91 in response to a command from the initial processing means 82.

Figure 3 is a time chart showing the drive state of the fuel injection device 90 when the engine is started. This embodiment is characterized in that when the engine is started, the fuel injection device 90 is driven to inject fuel during the initial processing of the fuel pump 93. From the top, this time chart shows the voltage, crank pulse, CPU startup state, operation of the fuel pump 93, and operation of the fuel injection device 90. Note that the operation of the fuel pump 93 shows only one phase of the three-phase pump, and the remaining two phases are omitted. Also, although a three-phase pump is used in this embodiment, a DC pump may also be used.

At time t=0, the operation of the kick starter 30 is started, the crankshaft S starts to rotate, and the ACG 50 starts to generate electricity. At time t1, the gradually increasing voltage reaches a predetermined value, which starts the CPU of the ECU 80, and the initial processing of the ECU 80 and the initial processing of the fuel pump 93 begin.

During period A from time t1 to t2, the engine speed Ne is calculated based on the inter-pulse time. During period B from time t2 to t3, it is determined whether the engine is being started by the kick starter 30 based on the engine speed Ne.

At time t4, initial injection, which is fuel injection during the initial processing of the fuel pump 90, is started. Initial injection continues until time t5 based on the value of the injection amount TOUT calculated in step S4 of the flowchart shown in FIG. 4. Note that the fuel injection device driving means 83 may count pulses after detecting the first toothless section 44 after the CPU is started, and control the fuel injection at the timing of the intake stroke or the combustion stroke.

The fuel injection time can be adjusted based on a table prepared in advance, and can also be changed according to the time t1 from when the ECU 80 is started and the number of counted pulses. For example, when the number of pulses is small, the fuel pressure is relatively low and the fuel injection time is the normal time plus a long time, while when the number of pulses is large, the fuel pressure is relatively high and the fuel injection time is the normal time plus a short time. When the ignition switch is turned from off to on while driving, the pump fuel pressure is assumed to remain sufficiently high, so initial injection is not performed. When the time t1 from when the ECU 80 is started is short, the fuel pressure is relatively low and the fuel injection time is the normal time plus a long time, while when the time t1 is long, the fuel pressure is relatively high and the fuel injection time is the normal time plus a short time.

At time t6, the ECU initial process ends. At time t7, the initial process of the fuel pump 93 ends and switches to normal operation. The time of the initial process T2 of the fuel pump 93 is longer than the time of the initial process T1 of the ECU 80, and the initial injection is performed during the execution of the initial process T1 of the ECU 80. The initial process T1 of the ECU 80 ends in a state where the functions of the ECU 80 are completely available. In other words, the initial process T1 of the ECU 80 ends in a state where the ECU 80 is able to receive pulses from the crank angle sensor 40, is able to issue a fuel injection command to the fuel pump 93 , and various other functions are completely available. The initial process T2 of the fuel pump 93 ends when the voltage value of the fuel pump 93 reaches a predetermined state. In this case, the fuel pump 93 is able to inject a predetermined amount of fuel in a predetermined fuel injection time.

Figure 4 is a flow chart showing the procedure for initial injection control. In step S1, it is determined whether or not a crank pulse is input. In step S2, the engine speed Ne is calculated based on the crank pulse interval. In step S3, it is determined whether or not the engine speed Ne is low. If it is determined in step S3 that the engine speed Ne is low, it is assumed that the engine is being started by the kick starter 30 in a battery-less vehicle, and the process proceeds to step S4. On the other hand, if the determination in step S3 is negative, it is assumed that the ignition switch (main switch) has been turned on and off while the engine is running, or that a reset has been performed, and the process proceeds to step S5.

If it is determined that the start is due to the kick starter 30, in step S4, the injection amount TOUT is set to a value obtained by adding the initial drive time extension to the normal injection amount. On the other hand, if the ignition switch is operated while driving, in step S5, the injection amount TOUT is set to zero. In step S6, a fuel injection signal is output according to the set TOUT, and the series of controls ends.

The initial process of the fuel pump 93 takes, for example, several tens of milliseconds. In this embodiment, the engine startability can be improved by injecting fuel before the initial process of the fuel pump 93 is completed. Also, if the fuel pressure generated by the fuel pump 93 is insufficient during the initial process, it is possible to supply sufficient fuel by extending the injection time.

As described above, according to the fuel injection method of this embodiment, the fuel injection time TOUT during the initial processing of the fuel pump 93 is longer than the normal injection time after the initial processing, so that the fuel injection amount can be made closer to the fuel injection amount at the time of completion of the initial processing. In addition, since fuel injection is performed during the initial processing of the fuel pump 93 and during the initial processing of the ECU 80, it is possible to speed up the start of the engine. In addition, since fuel injection is performed during the intake stroke or the combustion stroke, fuel injection can be performed at an appropriate timing even if the stroke discrimination is not completed immediately after the engine is started. In addition, the number of pulses output from the crank angle sensor 40 is counted from the start of the ECU 80 to the first fuel injection, and the smaller the number of pulses, the longer the fuel injection time, while the more the number of pulses, the closer the fuel injection time is to the normal injection time, so that the fuel injection can be adjusted to an appropriate amount according to the pump pressure rise situation. Furthermore, the engine starting device 100 includes a rotation speed calculation means 81 that calculates the rotation speed of the engine E, and when the rotation speed calculated by the rotation speed calculation means 81 is less than an arbitrarily set threshold, the fuel injection time is made longer than during normal injection, so that when starting is performed using a kick starter, the fuel injection time can be made longer to improve the startability of the engine.

Figure 5 is a time chart showing the driving state of the ignition device 91 when the engine is started. This embodiment is characterized in that when the engine is started, the ignition device 91 is driven after the initial processing of the ECU 80 is completed and before the stroke determination of the engine E is completed. From the top, this time chart shows the engine stroke, crank angle, and crank pulse, and below that show a total of 22 examples of driving the ignition device 91 with different timings.

This embodiment is characterized in that it improves engine startability by starting fixed ignition control as early as possible after the completion of the initial processing of the ECU 80. Specifically, after the completion of the initial processing, the supply of electricity to the ignition device 91 starts with the third pulse, and ignition occurs with the fifth pulse. However, if the stroke of engine E is in the damage area (compression stroke or exhaust stroke of the gray colored part in the figure) at the timing of ignition, soft-off discharge is performed without ignition, that is, ignition in the damage area is prohibited, thereby protecting engine E.

For example, in the case of driving example C of the ignition device 91, current is started at the third pulse after the end of the initial processing, and ignition is performed at the fifth pulse, but in the case of driving example D, current is started at the third pulse after the end of the initial processing, but since there is a toothless section of the crank pulse between the end of the initial processing and the fifth pulse, it is determined that the crank angle is in the damage area, and soft-off discharge is performed at the fifth pulse. In this way, by avoiding ignition in the damage area and performing ignition as early as possible in the combustion stroke or intake stroke, it is possible to improve the startability of the engine E. In both cases, this ignition is performed after top dead center, but the torque generated by combustion can lead to the implementation of the next regular fixed ignition.

Figure 6 is a flowchart showing the procedure for fixed ignition control. In step S10, it is determined whether the initial processing of the ECU 80 has been completed. In step S11, it is determined whether or not the battery-less kick start is performed, and if the determination is affirmative, the process proceeds to step S12. On the other hand, if the determination is negative in step S11, the process proceeds to step S15, where the process transitions to conventional fixed ignition control, and the series of controls is terminated.

In step S12, the number of pulses is counted and the inter-pulse time is stored. In step S13, it is determined whether the current pulse is the third pulse, and if the determination is affirmative, the process proceeds to step S14, where current is started for fixed ignition. On the other hand, if the determination is negative in step S13, the process proceeds to step S16, where it is determined whether the current pulse is the fifth pulse, and if the determination is affirmative, the process proceeds to step S17.

In step S17, the ratio of the inter-pulse time is calculated. In the following step S18, it is determined whether there is a missing tooth section up to the 5th pulse. If the determination is affirmative that there is no missing tooth section, the process proceeds to step S19, where fixed ignition is performed. On the other hand, if the determination is negative in step S18, that is, if it is determined that there is a missing tooth section up to the 5th pulse and therefore that it is in the damaged area, the process proceeds to step S20, where fixed ignition is stopped, and the series of controls ends.

Figure 7 is an explanatory diagram showing a method for determining the presence or absence of a tooth-missing section based on the crank pulse. As described above, the presence or absence of a tooth-missing section is determined by determining whether or not there is a tooth-missing section between the input of the first pulse and the input of the fifth pulse. The ratio of the pulse interval is calculated by dividing the current pulse interval by the previous pulse interval. If this value is 3.0 or 0.3, it is determined that there is a tooth-missing section. The ratio of the pulse interval for determining the presence or absence of a tooth-missing section is 1.0 for the example (1), 3.0 for the example (2), 3.0 for the example (3), 3.0 for the example (4), 0.3 for the example (5), and 1.0 for the example (6). In other words, (1) and (6) are considered to have no tooth-missing and ignition control is executed at the fifth pulse, while (2) to (5) are considered to have tooth-missing and soft-off discharge is executed at the fifth pulse.

As described above, according to the engine ignition method of this embodiment, the pulses output from the crank angle sensor 40 are counted after the initial processing of the ECU 80 is completed, and when the number of pulses exceeds a first threshold value (3 in this embodiment), the ignition device 91 starts to be energized, and when the number of pulses exceeds a second threshold value (5 in this embodiment) that is greater than the first threshold value, ignition is performed by the ignition device 91. Therefore, after the initial processing of the control device, ignition can be performed before the engine stroke determination is completed. This makes it possible to speed up the start of the engine. In addition, the crank angle sensor 40 is provided with a toothless section 44 in which no pulses are output, and if there is a toothless section 44 between the start of the pulse count and the exceeding of the second threshold value, ignition is prohibited, so that the generation of torque in the reverse rotation direction can be prevented. In addition, since the section in which ignition is performed by the ignition device 91 is the combustion stroke or the intake stroke, the generation of torque in the forward rotation direction can be promoted. In addition, because the section in which ignition by the ignition device 91 is prohibited is the compression stroke or the exhaust stroke, it is possible to prevent the generation of torque in the reverse rotation direction. Furthermore, if the ratio calculated by dividing the current inter-pulse time by the previous inter-pulse time exceeds a predetermined value, the ECU 80 determines that there is a missing tooth section 44, so it can accurately detect the missing tooth section.

The shape of the motorcycle, the type of engine, and the structure and shape of the fuel injection device and ignition device are not limited to the above embodiment and can be modified in various ways. The fuel injection method and engine ignition method of the present invention can be applied not only to motorcycles but also to saddle-type three-wheeled and four-wheeled vehicles equipped with a kick starter.

1...Motorcycle (saddle-type vehicle), 30...Kick starter, 40...Crank angle sensor, 44...Tooth-missing section, 50...ACG (generator), 80...Control device, 81...Rotational speed calculation means, 90...Fuel injection device, 91...Ignition device, 93...Fuel pump, 100...Engine starting device, E...Engine, S...Crankshaft, TOUT...Fuel injection time

Claims (5)

A fuel injection method applied to an engine starting device (100) including a kick starter (30) for manually rotating a crankshaft (S) of an engine (E), a generator (50) for synchronously rotating with the crankshaft (S), a crank angle sensor (40), a fuel injection device (90) for injecting fuel pumped from a fuel pump (93), and a control device (80) for controlling the fuel injection device (90),
Fuel injection is performed during an initial process in which the fuel pressure has not yet increased immediately after the fuel pump (93) is started,
The fuel injection time (TOUT) during the initial process of the fuel pump (93) is longer than that during normal injection after the initial process,
Fuel injection is performed during an initial process of the fuel pump (93) and during an initial process as an initialization process for preparing the control device (80) for driving ;
A fuel injection method comprising: counting the time from the start-up of the control device (80) to the first fuel injection; and the shorter the time, the longer the fuel injection time; and conversely, the longer the time, the closer the fuel injection time becomes to normal injection. The engine starting device (100) includes a rotation speed calculation means (81) for calculating a rotation speed of the engine (E),
2. The fuel injection method according to claim 1, further comprising the step of: making a fuel injection time longer than that during normal injection when the rotation speed calculated by the rotation speed calculation means (81) is less than a threshold value. The fuel injection method according to claim 1 or 2, characterized in that the initial processing of the fuel pump (93) is terminated when the voltage value of the fuel pump (93) reaches a predetermined state. A fuel injection system having an engine starting device (100) including a kick starter (30) for manually rotating a crankshaft (S) of an engine (E), a generator (50) for synchronously rotating with the crankshaft (S), a crank angle sensor (40), a fuel injection system (90) for injecting fuel pumped from a fuel pump (93), and a control device (80) for controlling the fuel injection system (90),
The control device (80) performs fuel injection during an initial process in which the fuel pressure has not yet increased immediately after the fuel pump (93) is started ,
The fuel injection time (TOUT) during the initial process of the fuel pump (93) is longer than that during normal injection after the initial process,
Fuel injection is performed during an initial process of the fuel pump (93) and during an initial process as an initialization process for preparing the control device (80) for driving ;
A fuel injection device characterized in that the time from the start of the control device (80) to the first fuel injection is counted, and the shorter the time, the longer the fuel injection time becomes, while the longer the time, the closer the fuel injection time becomes to normal injection. The fuel injection device according to claim 4, characterized in that the initial processing of the fuel pump (93) is terminated when the voltage value of the fuel pump (93) reaches a predetermined state.

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