JP2604042B2 - Engine fuel injection control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel injection control device for an engine with improved startability.

[Prior Art and Problems to be Solved by the Invention] In recent years, a technique of engine fuel injection control by a microcomputer has been established.
Already widely used in four-stroke engines.

Next, various proposals have been made to employ the above-described microcomputer fuel injection control technology also in a two-cycle engine. For example, Japanese Patent Application Laid-Open No. 63-255543 discloses a main intake passage for introducing fresh air into a crankcase. A fuel injection valve (injector) is disposed in each of a fuel injection valve and an auxiliary intake passage that directly introduces fresh air into the crank chamber, and a technique is provided in which control means for controlling the injection timing and injection amount of each fuel injection valve is provided. I have.

In such a combustion injection control device using a microcomputer, for example, as disclosed in JP-A-63-29039, a map search is performed for the intake air amount Q using the throttle opening α and the engine speed N as parameters. And the basic fuel injection amount Tp based on the intake air amount Q.
Is calculated, and various corrections based on the engine operating state are added to the basic fuel injection amount to calculate a final fuel injection amount.

In this case, in many cases, the fuel injection control device generally calculates the engine speed N using a rotation speed sensor such as a crank angle sensor, and performs fuel injection in synchronization with the rotation of the engine in many cases. When such a switch is turned off, the fuel injection and the driving of the fuel pump are stopped.

Therefore, when the fuel injection is stopped and the driving of the fuel pump is stopped due to the stop of the engine, the driving of the fuel pump may be stopped first, and then the fuel injection may be stopped, and the fuel pump may stop with the fuel pressure lowered. .

When the engine is restarted in such a state, it takes time to recover the fuel pressure even if the fuel pump is driven again. There is a problem that it causes the deterioration of.

[Object of the Invention] The present invention has been made in view of the above circumstances, and when the engine is stopped, the fuel injection is reliably stopped before the fuel pump is stopped, and the fuel pressure is maintained to achieve good starting performance. It is an object of the present invention to provide an engine fuel injection control device that can be obtained.

[Means for Solving the Problems] A fuel injection control device for an engine according to the present invention is output in synchronism with engine rotation from an electronic ignition device that short-circuits an ignition power supply by inputting an engine stop signal and cuts off ignition. Fuel injection is performed based on the engine rotation parameter and the engine operation state parameter obtained by measuring the output interval time of the ignition pulse signal, and the parameter related to the engine rotation has reached a preset fuel injection stop limit value. When the fuel injection control means for stopping the fuel injection, and after stopping the fuel injection by the fuel injection control means, a parameter relating to the engine rotation is a fuel pump stop limit value larger than the fuel injection stop limit value. And a fuel pump control means for stopping the driving of the fuel pump in the event of the occurrence.

[Operation] In the fuel injection control device for an engine according to the present invention, the parameters relating to the engine rotation and the engine operating state obtained by measuring the output interval time of the ignition pulse signal output from the electronic ignition device in synchronization with the engine rotation are described. When an engine stop signal is input in an engine operating state in which fuel injection is performed based on the parameters, the ignition power supply is short-circuited by the electronic ignition device to perform ignition cut. Then, due to this ignition cut, the rotation of the engine is reduced, and eventually, when the parameter relating to the engine rotation reaches the fuel injection stop limit value, the fuel injection is stopped, and after the fuel injection is stopped, the fuel injection is further reduced. When the parameter reaches the fuel pump stop limit value larger than the fuel injection stop limit value, the driving of the fuel pump is stopped.

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

1 to 7 show a first embodiment of the present invention, FIG. 1 is a functional block diagram of a control device, FIG. 2 is a schematic diagram of an engine control system, FIG. 3 is a circuit diagram of a CDI unit, 4 is a front view of the flywheel, FIG. 5 is a flowchart showing a control procedure of a self-shut relay, FIG. 6 is a flowchart showing a fuel pump control procedure, and FIG. 7 is a flowchart showing a fuel injection control procedure.

(Configuration of Engine Control System) In FIG. 2, reference numeral 1 in the drawing denotes an engine body, which indicates, for example, a three-cylinder two-cycle engine mounted on a snowmobile or the like. An intake port 2a and an exhaust port 2b are formed in a cylinder block 2 of the engine body 1,
Further, an ignition plug 4 whose tip is exposed to the combustion chamber is attached to each cylinder of the cylinder head 3.

A crankcase temperature sensor 6 faces the crankcase 5 of the engine body 1, and a water jacket 7 is provided on the crankcase 5, the cylinder block 2, and the cylinder head 3.

Also, each intake port 2a of the cylinder block 2
An intake manifold 9 is communicated through an insulator 8, a throttle valve 9 a provided in the intake manifold 9 is provided with a throttle opening sensor 10. Immediately upstream, an injector 11 is provided.

An air box 12 containing an air cleaner (not shown) is communicated upstream of the intake manifold 9, and an air temperature sensor 13 faces the air box 12.

The injector 11 is connected to a fuel tank 15 via a fuel supply path 14, and a fuel filter 16 and a fuel pump 17 are interposed in the fuel supply path 14 from the fuel tank 15 side.

Further, as shown by a dashed line in the figure, the injector 11 communicates with a fuel chamber 18a of a pressure regulator 18, and the downstream side of the fuel chamber 18a is communicated with the fuel tank 15, and the adjustment of the pressure regulator 18 is performed. The pressure chamber 18b communicates with the intake manifold 9.

That is, from the fuel tank 15 to the fuel filter 16
The fuel pumped by the fuel pump 17 passes through the injector 11 and the pressure regulator 18, and is supplied to the injector 11 while the pressure difference between the pressure in the intake manifold 9 and the fuel pressure is kept constant. The fuel injection amount from the injector 11 is controlled so as not to fluctuate due to the fluctuation of the pressure in the intake manifold 9.

(Circuit Configuration of Control Unit) On the other hand, reference numeral 20 denotes a control unit (ECU) composed of a microcomputer, and the CPU (Central Processing Unit) 21, the ROM 22, the RAM 23, the backup RAM 24, and the I / O of the ECU 20
Interfaces 25 are connected to each other via a bus line 26, and a predetermined stabilized voltage is supplied from a constant voltage circuit 27.

The constant voltage circuit 27 is connected to a battery 30 via two relay contacts connected in parallel to each other, a relay contact of an ECU relay 28, and a relay contact of a self-shut relay 29, and is supplied with control power. , Battery 30 above
When the control power supply is turned off, backup power is supplied to the backup RAM 24 to retain data.

The ECU relay 28 has two sets of relay contacts, and its electromagnetic coil 28a is connected to the battery 30 via an ignition switch 31 and a kill switch 32. The ignition switch 31 and the kill switch 32 are
When the ON terminals are connected in series and the respective OFF terminals are connected in parallel, and the switches 31 and 32 are both ON, the ECU relay 28 turns ON and the constant voltage circuit via one of the relay contacts. Supply control power to 27.

On the other hand, when one of the ignition switch 31 and the kill switch 32 is in the OFF position and an engine stop signal is output, the line from the CDI unit 33, which is an electronic ignition device, is short-circuited and ignition is cut off.

The kill switch 32 is a stop switch provided on a grip of a snowmobile (not shown) or the like, and the line from the CDI unit 33 is a line from an ignition power supply short circuit 33b to be described later.

Further, the battery 30 includes an electromagnetic coil 29a of the self-shut relay 29, the injector 11, and
One end of an electromagnetic coil 34a of the fuel pump relay 34 is connected, and the fuel pump 17 is connected via a relay contact of the fuel pump relay 34.

The self-shut relay 29 is used to supply power to the ECU 20 for a preset time (for example, 10 minutes) after one of the ignition switch 31 and the kill switch 32 is turned off and the engine is stopped. When restarting at a high temperature without cooling the engine,
This is to prevent the starting fuel injection amount from the injector 11 from being increased and corrected to prevent the air-fuel ratio from becoming over-rich and difficult to start.

The input ports of the I / O interface 25 of the ECU 20 are connected to the sensors 6, 10, 13 and an atmospheric pressure sensor 36 built in the ECU 20, and further connected to an MR resistor 35. While the reference voltage VCC is divided and input, a signal line from the CDI unit 33 is connected, a CDI pulse described later is input, and the other relay contact of the ECU relay 28 is connected to the ECU relay terminal voltage VB. Monitored.

The MR resistor 35 is an adjustment resistor for adjusting the idling speed.
The adjustment voltage from the resistor 35 is read, and a pulse width corresponding to the adjustment voltage is added to or subtracted from the basic fuel injection pulse width, and the idling speed is adjusted by increasing or decreasing the fuel injection amount from the injector 11. Things.

Further, a failure diagnosis mode switching connector 37 for switching the self-diagnosis function of the ECU 20 between a U check mode (user use mode) and a D check mode (dealer check mode) is connected to the input port of the I / O interface 25. In addition, a failure diagnosis connector 38 is connected, and when a failure occurs, a failure diagnosis is performed by connecting a vehicle diagnosis serial monitor 39 indicated by a two-dot chain line to the failure diagnosis connector 38.

Note that the failure diagnosis mode switching connector 37 is usually
In the U-check mode, if an error occurs in the system, the trouble data is stored in the backup RAM 24
And stored. At a dealer's service station, the serial monitor 39
Is connected to the ECU 20 via the failure diagnosis connector 38, trouble data is read out from the backup RAM 24 to perform failure diagnosis, and the failure diagnosis mode switching connector 37 is switched to the D check mode for more details. Perform a fault diagnosis.

On the other hand, at the output port of the I / O interface 25, the injector 11, the electromagnetic coil 34a of the fuel pump relay 34, and the electromagnetic coil 29a of the self-shut relay 29 have a drive circuit 40 at the other end. Connected through.

(Circuit Configuration of Ignition Apparatus) A magnet 41 is connected to a crankshaft 1a of the engine body 1, and an exciter coil 41 of the magnet 41 is provided.
a, the pulsar coil 41b is connected to the CDI unit 33, and the primary side of the ignition coil 4a is connected to the CDI unit 33.

Further, the magneto 41 is provided with a lamp coil 41c and a charge coil 41d, and the lamp coil 41c is
Electric loads such as lamps and heaters via regulator 43
The power supply is connected to the battery 30 and supplies power independently of the battery 30, and the charge coil 41d is connected to the battery 30 via a rectifier 42 to charge the battery 30.

As shown in FIG. 3, the CDI unit 33 includes an ignition circuit 33a, an ignition power supply short circuit 33b, a pulse detection circuit 33c,
It is composed of a waveform shaping circuit 33d, a duty control circuit 33e, and a pulse generation circuit 33f.
The primary side of each ignition coil 4a of each ignition plug 4 arranged in each cylinder is connected in parallel, the pulse detection circuit 33c is connected, and the ignition power supply short circuit 33b is connected to the ignition circuit 33a. One end is connected to the ground G.

The ignition circuit 33a and the ignition power supply short circuit 33b are connected to an ignition power supply VIG via the diode D1 from the exciter coil 41a of the magnet 41, and the ignition switch 31 and the kill switch 32 are connected to the cathode of the diode D1. Are connected in parallel and the resistor R
1. Connected to the gate of the engine stop thyristor SCR2 of the ignition power supply short circuit 33b via a diode D2.

The ignition circuit 33a is a well-known capacitive discharge ignition circuit including an ignition capacitor C1 and an ignition thyristor SCR1 connected to the ignition power supply VIG.
Pulsar coil 41b opposed to 41 flywheel 41e
In addition, the gate of the ignition thyristor SCR1 is a diode D
3. Connected via a resistor R2, and an ignition trigger signal is input from the pulsar coil 41b at a predetermined timing.

As shown in FIG. 4, on the outer periphery of the flywheel 41e, before the compression top dead center (BTDC) θ2 of each of the # 1, # 2, and # 3 cylinders
At positions (eg, θ2 = 15 to 20 °), protrusions 41f (slits may be formed) at intervals of θ1 (eg, θ1 = 120 °), and the protrusions 41f are rotated with the rotation of the flywheel 41e. When 41f passes through the pulsar coil 41b, an ignition trigger signal is output from the pulsar coil 41b by electromagnetic induction.

The ignition power supply short circuit 33b includes an anode of a first diode D4 and an anode of a second diode D5 connected to the ignition power supply VIG.
The cathodes of D4 and the second diode D5 are both connected to the anode of the engine stop thyristor SCR2 via a resistor R3 and a trigger capacitor C2, respectively, and the cathode of the engine stop thyristor SCR2 is connected to ground G. ing.

Further, the cathode of the second diode D5 connected to the trigger capacitor C2 is connected to the emitter of a trigger transistor TR formed of a PNP transistor, and the base of the trigger transistor TR is connected to a resistor R4.
Is connected to the anode of the thyristor SCR2 for stopping the engine.

Further, the collector of the trigger transistor TR is
It is connected to the gate of the thyristor SCR2 for stopping the engine via a resistor R5 and a diode D6, and between the gate of the thyristor SCR2 for stopping the engine and the ground G, the influence of noise or the rate of increase of the critical OFF voltage. A resistor R6 and a capacitor C3 are connected in parallel to prevent the commutation of the circuit.

The waveform shaping circuit 33d and the duty control circuit 33
e, and the pulse generation circuit 33f is connected to the battery 30 through the respective ON terminals of the ignition switch 31 and the kill switch 32 connected in series, and from the pulse generation circuit 33f to the ignition power supply VIG. A synchronized CDI pulse is output (see FIG. 3) and input to the I / O interface 25 of the ECU 20.

That is, in the present embodiment, the pulsar coil
An ignition trigger signal is output from the 41b at every crank angle of 120 °, ignition is performed simultaneously for all cylinders (three cylinders) three times per engine revolution, and a CDI pulse is generated from the pulse generation circuit 33f at every crank angle of 120 °. The fuel is injected from each injector 11 simultaneously from each injector 11 once per engine revolution, triggered by the output of the CDI pulse.

(Functional Configuration of Control Device) As shown in FIG. 1, functions related to fuel injection control of the ECU 20 include a fuel pump control unit 51, a fuel injection control unit 52,
ECU relay state determination means 53, counter means 54, ECU relay
It comprises OFF elapsed time determination means 55 and self-shut-down relay driving means 56.

Further, the fuel pump control unit 51 includes a first timer control unit 51a, a first timer unit TM1, and a second timer control unit 51a.
b, a second timer means TM2, a storage means 51c comprising a RAM 23, an initial discrimination means 51d, an initial time discrimination means 51e, a CDI pulse input interval time discrimination means 51f, and a fuel pump relay drive means 51g. The control means 52 includes an engine speed calculation means 52a, a fuel injection pulse width setting means 52b,
It comprises a fuel cut determination means 52c and an injector drive means 52d.

In the fuel pump control means 51, the first timer control means 51a
When the ECU relay terminal voltage VB is applied, it is determined that the ECU relay 28 has been turned on from OFF and the first timer means TM1
Is initialized and reset. Then, the first timer means TM1 is triggered to start timing, and the initial determination flag FLAG1 of the storage means 51c (RAM23) is set (F
LAG1 ← 1).

In the first timer means TM1, the first timer control means 51a
The timer starts counting by the trigger from, and outputs the counting time T1 to the initial time determining means 51e.

In the second timer control means 51b, the CDI unit 33
Each time a pulse is input, the timer time T2 is read from the second timer means TM2, and the measured time T2 is stored in the storage means 51c (RAM 23) as the CDI pulse input interval time T120 (T120
← T2) Then, the second timer means TM2 is reset and triggered to newly start time measurement.

The CDI pulse input interval time T120 is the elapsed time of the crank angle θ1 (θ1 = 120 °) corresponding to the angle between the protrusions 41f on the outer periphery of the flywheel 41e of the magneto 41, and is used when calculating the engine speed described later. Parameters, ie
This is a parameter related to engine rotation.

In the second timer means TM2, the second timer control means 51a
Then, the timer starts counting, and outputs the measured time T2, that is, the elapsed time after the CDI pulse is input, to the CDI pulse input interval time determining means 51f.

The initial determination means 51d checks the value of the initial determination flag FLAG1 stored in the storage means 51c (RAM 23),
When the flag is 1, the ECU relay 28 is switched from OFF to ON to determine the initial state in which the engine is started, and a determination operation instruction is issued to the initial time determination means 51e. On the other hand, when FLAG1 = 0, the CDI pulse input interval time determination is performed. The determination operation is instructed to the means 51f.

The initial time discriminating means 51e reads the measured time T1 from the first timer means TM1 and compares it with a predetermined set time T1SET (for example, 1SEC). Turn on fuel pump relay 34
Then, the fuel pump 17 is driven.

On the other hand, when T1 <T1SET, the first timer control means
Instruct the first timer means TM1 to reset the first timer means TM1 and clear the initial determination flag FLAG1 of the storage means 51c (RAM23) (FLAG1 ← 0).

The CDI pulse input interval time discriminating means 51f reads the measured time T2 from the second timer means TM2 and compares it with the fuel pump stop limit value T2SET (for example, 1 + ASEC; A is equivalent to 1 bit of the minimum resolution with respect to time in the ECU 20). I do.

When T2 ≧ T2SET, that is, because the engine is stopped,
Ignition switch 31 or kill switch 32 is off
F, when the ignition cut is performed and the CDI pulse is not input even after the fuel pump stop limit value T2SET or more has elapsed, it is determined that the ignition has been cut and the fuel pump relay 34 is passed through the fuel pump relay driving means 51g. Is turned off, and the fuel pump 17 is stopped.

On the other hand, when T2 <T2SET, it is determined that the engine is in the operating state, the fuel pump relay 34 is kept ON via the fuel pump relay driving means 51g, and the driving of the fuel pump 17 is continued.

In the fuel injection control means 52, the engine speed calculating means 52a calculates the CDI pulse input interval time T120 stored in the storage means 51c (RAM 23) and the crank angle θ1 (corresponding to the CDI pulse input interval). θ1 = 120 °), the cycle f is obtained (f = dT120 / dθ1), and the engine speed N is calculated from this cycle f (N = 60 / 2πf).

In the fuel injection pulse width setting means 52b, the engine speed N calculated by the engine speed calculating means 52a, the ECU relay terminal voltage VB, that is, the battery voltage VB, the throttle opening α from the throttle opening sensor 10, the crankcase temperature The fuel injection pulse width Ti is set based on the engine operating state parameters such as the crankcase temperature TmC from the sensor 6, the atmospheric pressure Pa from the atmospheric pressure sensor 36, and the intake air temperature Ta from the intake air temperature sensor 13.

Then, a drive pulse width signal corresponding to the fuel injection pulse width Ti is output to the injector 11 via the injector driving means 52d, a predetermined amount of fuel is injected, and the fuel cut determination means 52c issues a calculation stop instruction. When input, Ti = 0 is output to the injector driving means 52d, and fuel cut, that is, fuel injection is stopped.

The fuel cut determining means 52c compares the engine speed N calculated by the engine speed calculating means 52a with the fuel injection stop limit value NSET, and when N <NSET, determines that the engine speed N has decreased due to the ignition cut. Then, it instructs the fuel injection pulse width setting means 52b to stop the calculation, and N ≧ NSET
At this time, it is determined that the engine is in the cranking or normal engine operating state, and a calculation instruction is issued to the fuel injection pulse width setting means 52b.

At this time, the fuel injection stop limit value NSET is, for example, 5
It is set to 0 rpm (period of 1.2 SEC), and this value corresponds to when the CDI pulse input interval time T120 becomes 0.4 SEC. That is, the above-described fuel pump stop limit value T2SET (for example, 1 + ASEC) is a sufficiently large value with respect to the fuel injection stop limit value NSET. When the engine is stopped, the fuel injection is stopped first, and thereafter, The drive of the fuel pump 17 is stopped.

Thus, when the engine is stopped, the fuel injection is reliably stopped before the drive of the fuel pump 17 is stopped, and the stop in the state where the fuel pressure is reduced can be prevented.

The ECU relay state determination means 53 reads the terminal voltage VB of the ECU relay 28, and determines whether the ECU relay 28 is ON or OFF to determine whether the ECU relay 28 is open or closed. As a result of the determination, the above EC
When the U relay 28 is ON, the self-shut relay 29 is turned ON via the self-shut
When the U relay 28 is turned off from ON, the counter unit 54 is instructed to start counting.

In the counter means 54, the ECU relay state determination means 53
ECU relay 28 is turned on by counting start instruction from
The elapsed time after turning OFF from is counted by the self-shut control counter.

The self-shut control counter is, for example, an EC
The timer operates by counting a reference time clock obtained by dividing the system clock of U20.

The ECU relay OFF elapsed time determination means 55 determines whether the count value C1 of the self-shut control counter in the counter means 54 is equal to or greater than a set value C1SET (for example, a count value corresponding to 10 minutes), and C1 < At C1SET,
Keep the self-shut relay 29 on and the ECU 20
Self-hold, and when C1 ≧ C1SET, the self-shut relay 29 is turned off via the self-shut-relay driving means 56, the power to the ECU 20 is cut off, the self-hold is released, and the system operates. Stop.

(Operation) Next, the operation of the embodiment having the above configuration will be described.

First, when the engine is cranked, the intermittent voltage generated in the exciter coil 41a of the magnet 41 is half-wave rectified by the diode D1 and applied, and the ignition circuit 33a
Is charged.

Then, a reference signal voltage is output from the pulsar coil 41b of the magneto 41 at a predetermined crank position, and the reference signal voltage is applied to the gate of the ignition thyristor SCR1 via the diode D3 and the resistor R2.

When the reference signal voltage reaches the trigger level of the ignition thyristor SCR1, the ignition thyristor SCR1 is turned on, and the electric charge stored in the ignition capacitor C1 is changed to the ignition capacitor C1 → the ignition thyristor SCR1 →
Discharged instantaneously into the closed circuit consisting of the ignition coil 4a primary side → capacitor C1. As a result, a high voltage with a very large rise is generated on the secondary side of the ignition coil 4a, and the spark plug 4 is sparked.

At the same time, the ignition waveform of the primary side of the ignition coil 4a is detected by a pulse detection circuit 33c, is shaped by a waveform shaping circuit 33d, is set to a predetermined pulse width by a duty control circuit 33e, and is fired by a pulse generation circuit 33f. Power supply VIG
Is output, and a fuel injection pulse is output to the injector 11 in synchronization with the CDI pulse, and the engine is started.

On the other hand, when stopping the engine, turning off the ignition switch 31 or the kill switch 32 causes a current to flow from the ignition power supply VIG to the gate of the engine stop thyristor SCR2 of the ignition power supply short circuit 33b via the resistor R1 and the diode D2. Then, the engine stop thyristor SCR2 is turned on. Then, the first diode D4 and the resistor R3
, The ignition power supply VIG is substantially short-circuited, and the trigger capacitor C2 is charged via the second diode D5.

Since the ignition power supply VIG is an intermittent voltage as shown in FIG. 3, the ignition power supply VIG is at the ground level until the engine stops, and the engine stop thyristor SCR2 is turned off. In this case, a discharge current flows from the trigger capacitor C2, and a base current is supplied to the trigger transistor TR to turn on the trigger transistor TR.

Then, by the conduction of the trigger transistor TR,
With the generation of the next ignition power supply VIG, the second diode D5 →
A gate current is directly supplied to the engine stop thyristor SCR2 through the path of the trigger transistor TR → the resistor R5 → the diode D6, the engine stop thyristor SCR2 is turned off again, the ignition power supply VIG is short-circuited, and the trigger is generated. Charge capacitor C2.

This process is repeated, the ignition power supply VIG is short-circuited, and the ignition energy required for discharging the ignition plug 4 is not supplied to the primary side of the ignition coil 4a, and the ignition energy is below the ignition limit value, and the engine stops. .

At this time, for example, if the kill switch 32 is once turned off and the engine stop thyristor SCR2 is turned on, the engine stop thyristor SCR2 is turned off by the intermittently generated ignition power supply VIG. It is not necessary to keep the switch 32 in the OFF state, and the engine stopping thyristor SCR2 automatically repeats turn-on from turn-off until the engine is stopped by the trigger capacitor C2 and the trigger transistor TR. When turning the stop thyristor SCR2 from turn-off to turn-on, the trigger capacitor TR is used to turn on the trigger transistor TR.
Since the discharge current of C2 itself is used and the gate current is supplied directly from the ignition power supply VIG to the engine stop thyristor SCR2, the engine stop thyristor SCR2 is turned on by the discharge current of the trigger capacitor C2 itself. As compared with the case, the discharge current of the trigger capacitor C2 can be reduced by the amplifying action of the trigger transistor TR, and the capacitor capacity can be greatly reduced.

(Self-shut-down relay control procedure) On the other hand, even after the engine stops, the ECU 20 is supplied with power by the self-shut-down relay 29 and is held in a self-holding state. Then, the power of the ECU 20 is turned off to stop the operation.

Next, the control procedure of the self-shut relay 29 is described in the fifth step.
This will be described with reference to the flowchart in FIG.

The program shown in FIG. 5 is executed at predetermined time intervals while the power is supplied to the ECU 20.

First, in step S101, the ECU relay terminal voltage VB is read, and then, the process proceeds to step S102, and whether the ECU relay terminal voltage VB read in step S101 is 0 or not,
It is determined whether the ECU relay 28 is OFF.

When VB = 0 in step S102, ie,
Ignition switch 31 or kill switch 32 is off
When F is turned off and the ECU relay 28 is turned off and the engine is stopped, the process proceeds from step S102 to step S103 to count up the self-shut control count value C1 (C1 ←
C1 + 1) In step S104, the self-shut control count value C1 is compared with a predetermined set value C1SET.

In step S104, when C1 <C1SET, the process proceeds from step S104 to step S107 to keep the self-shut relay 29 ON and exits the routine. When C1 ≧ C1SET, the process proceeds from step S104 to step S105 to perform self-shutdown. Turn off relay 29. Thereby, the power supply to the ECU 20 is turned off and the operation is stopped.

On the other hand, when VB ≠ 0 in step S102, that is, when the ECU relay 28 is not turned off and the engine is operating, the process proceeds from step S102 to step S106 to clear the self-shut control count value C1. (C1 ←
0) In step S107, the self-shut relay 29 is kept ON and the routine exits.

(Fuel Pump Control Procedure) When the ECU relay 28 is turned on from the off state, the program of the fuel pump control procedure shown in FIG. 6 is executed.

That is, when the power of the ECU 20 is turned on from the OFF state and the engine is started while the engine is stopped, or when the power of the ECU 20 is maintained in the ON state by the self-shut-off relay 29 described above. 6A, the program shown in the flowchart of FIG. 6A is executed only once, and then the program shown in the flowchart of FIG. 6. The program shown in the flowchart of FIG. 6C is started by interruption at a predetermined time or at predetermined intervals.

First, in the program shown in FIG.
In step S201, the timer TM1 is initialized and reset, and in step S202, the timer TM1 is triggered to start timing.

Next, proceeding to step S203, the initial determination flag FLAG1 is set (FLAG1 ← 1), and the program ends.

In addition, every time a CDI pulse is input, the program shown in FIG. 6 (b) is started, and in step S211, the time T2 of the timer TM2 is set as the CDI pulse input interval time T120 from the CDI unit 33, and the predetermined time in the RAM 23 is set. In step S212, the timer TM2 is reset. Then, the process proceeds to step S213, where the timer TM2 is triggered to start time measurement, and the routine exits.

When the program is the first time, the step S211 is jumped and the program is executed from the step S212.

In the program shown in FIG.
In step S221, the value of the initial determination flag FLAG1 is checked. If FLAG1 = 1, the process proceeds to step S222. If FLAG1 = 0, the process proceeds to step S22.
Proceed to 6.

In the above step S221, when FLAG1 = 1, that is, in the initial state, in step S222, the timer time TM
1 is read and the process proceeds to step T223.

In step S223, the clock time T1 read out in step S222 is compared with a predetermined set time T1SET (for example, 1SEC). When T1 <T1SET, it is determined that the initial state has ended, and the flow advances to step S228 to go to step S228. Turn on the fuel pump
Drive 17

On the other hand, when T1 ≧ T1SET in step S223, the process proceeds from step S223 to step S224, where the timer TM
1 is reset, and in step S225, the initial determination flag FLA
G1 is cleared (FLAG1 ← 0), and the process proceeds to step S226.

When the initial state ends and the process proceeds from step S221 or step S225 to step S226, the timer time T2 is read out from the timer TM2, and the process proceeds to step S227 to compare with the predetermined set time T2SET.

If T2 <T2SET in the above step S227, step
Proceeding to S228, the fuel pump relay 34 is kept ON and the routine is exited. On the other hand, when T2 ≧ T2SET, that is, when the engine is stopped, the ignition switch 31 or the kill switch 32 is turned off, the ignition is cut, and the CDI is performed. If the pulse is not input even after the lapse of a predetermined time T2SET or more, it is determined that the ignition has been cut and the fuel pump relay
Then, the fuel pump 17 is stopped, and the routine exits.

(Fuel Injection Control Setting Means) Next, the fuel injection control procedure will be described with reference to the flowchart of FIG.

First, in step S301, the CDI pulse input interval time T120 is read from the RAM 23, and in step S302, the cycle f is obtained from the CDI pulse input interval time T120, and the engine speed N is calculated from the cycle f (N = 60 / 2πf).

Next, the process proceeds to step S303, where the engine speed N calculated in step S302 is compared with a predetermined set speed NSET (for example, 50 rpm). When N ≧ NSET, it is determined that the engine is in a cranking or normal engine operating state. Then, the process proceeds from step S303 to step S304, where the engine speed N, the battery voltage VB, the throttle opening α from the throttle opening sensor 10, the crankcase temperature TmC from the crankcase temperature sensor 6, the atmospheric pressure sensor 36 The operation state parameters such as the atmospheric pressure Pa from the intake air and the intake air temperature Ta from the intake air temperature sensor 13 are read.

Then, in step S305, the fuel injection pulse width Ti is set based on the engine speed N calculated in step S302 and the engine operating state parameter read in step S304, and the process proceeds to step S306. The injector 11 outputs a drive pulse width signal corresponding to the injection pulse width Ti.
And output to the routine.

On the other hand, if N <NSET in step S303, it is determined that the engine speed N has decreased due to the ignition cut, and the routine proceeds to step S307 to perform fuel cut (Ti ← 0), and the routine exits.

(Second Embodiment) FIGS. 8 and 9 show a second embodiment of the present invention.
FIG. 9 is a functional block diagram of the control device, and FIG. 9 is a flowchart showing a fuel injection pulse width setting procedure.

The second embodiment differs from the first embodiment only in the fuel cut determination means 52e of the fuel injection control means 52. The fuel injection stop limit value is set to a value corresponding to the engine speed set in the first embodiment. It is set as time.

That is, in the fuel cut determination means 52e, the storage means 51c
(RAM23), the CDI pulse input interval time T120 is read, and the CDI pulse input interval time T120 and the fuel injection stop limit value TS
Compare with ET (eg, 0.4SEC).

When T120 ≧ TSET, the ignition cut causes the above C
It is determined that there is no DI pulse input, and the fuel injection pulse width setting means 52b is instructed to stop the calculation. When T120 <TSET,
It is determined that the engine is in a cranking state or a normal engine operating state, and gives a calculation instruction to the fuel injection pulse width setting means 52b.

(Fuel Injection Control Procedure) The fuel injection control procedure in such a configuration will be described with reference to the flowchart of FIG.
01, the CDI pulse input interval time T120 is read from the RAM 23,
In step S402, the CDI pulse input interval time T120 is compared with a predetermined set time TSET (for example, 0.4SEC).
When 0 <TSET, it is determined that the engine is in the cranking or normal operation state, and the process proceeds from step S402 to step S403. Thereafter, as in the first embodiment, the operation state parameters are read, and the fuel injection pulse width Ti is set in step S404. Then step
In T405, the fuel injection pulse width Ti is output, and the routine exits.

On the other hand, when T120 ≧ TSET in step S402, it is determined that the ignition has been cut, and the flow advances to step S406 to perform fuel cut (Ti ← 0), and the routine exits.

It should be noted that the present invention is not limited to the embodiment, and the fuel injection stop limit value and the fuel pump stop limit value may be an angular speed in addition to the engine speed and time.

[Effects of the Invention] As described above, according to the present invention, the parameters related to the engine rotation and the engine operation obtained by measuring the output interval time of the ignition pulse signal output from the electronic ignition device in synchronization with the engine rotation When an engine stop signal is input in an engine operating state in which fuel injection is performed based on the state parameters, the ignition power supply is short-circuited by the electronic ignition device, and ignition is cut off. The fuel injection is stopped when the parameter related to the engine rotation reaches the fuel injection stop limit value, and after the fuel injection is stopped, the parameter related to the engine rotation is more than the fuel injection stop limit value. When the fuel pump stop limit reaches a large value, the fuel pump is stopped. The decrease in power is kept to a minimum, and the fuel pressure can be quickly recovered when the engine is restarted, so that good startability can be obtained. In this case, even when the engine is restarted immediately after the engine is stopped, the air-fuel ratio required for the start can be secured by the injected fuel before the fuel pump is stopped, and the startability can be improved.

[Brief description of the drawings]

1 to 7 show a first embodiment of the present invention, FIG. 1 is a functional block diagram of a control device, FIG. 2 is a schematic diagram of an engine control system, FIG. 3 is a circuit diagram of a CDI unit, FIG. 4 is a front view of the flywheel, FIG. 5 is a flowchart showing a control procedure of a self-shut relay, FIG. 6 is a flowchart showing a fuel pump control procedure, FIG. 7 is a flowchart showing a fuel injection control procedure, FIG. The following figures show a second embodiment of the present invention, FIG. 8 is a functional block diagram of a control device, and FIG.
FIG. 5 is a flowchart showing a fuel injection control procedure. 1 Engine body 17 Fuel pump 51 Fuel pump control means 52 Fuel injection control means T120 CDI pulse output interval time N Engine rotation speed T2SET Fuel pump stop limit value NSET, TSET ...... Fuel injection stop limit value

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Claims (1)

(57) [Claims] An engine rotation obtained by measuring an output interval time of an ignition pulse signal output in synchronization with the engine rotation from an electronic ignition device for performing an ignition cut by short-circuiting an ignition power supply in response to an input of an engine stop signal. A fuel injection control means for performing fuel injection based on the parameters related to the above and the engine operation state parameter, and stopping the fuel injection when the parameter related to the engine rotation reaches a preset fuel injection stop limit value; A fuel pump control means for stopping the driving of the fuel pump when the parameter relating to the engine rotation becomes a fuel pump stop limit value larger than the fuel injection stop limit value after the fuel injection is stopped by the injection control means. A fuel injection control device for an engine, comprising: