JPH06200799A - Fuel feed control device for internal combustion engine - Google Patents

Abstract

(57) [Summary] (Correction) [Configuration] Driving the injector 32 that supplies fuel to the internal combustion engine at the time of start-up according to the detection outputs of the water temperature sensor 34 and the crank angle sensor 37 that detect the temperature of the cooling water. Depending on the starting pulse width calculating means 43 for calculating the widths of the first and second starting pulses, and the output of the starting pulse width calculating means, when the temperature of the cooling water is lower than a predetermined temperature, a high constant frequency and short Generating the first starting pulse having a pulse width, and synchronizing with the rotation of the internal combustion engine when the temperature of the cooling water is higher than a predetermined temperature, and a pulse width lower than the frequency and longer than the pulse width. And a drive pulse generating means 44 for generating and supplying the second start pulse to the injector.
Is equipped with. [Effect] When the cooling water temperature at the time of starting is low, the injector is driven by the first starting pulse of a high constant frequency, so atomization of fuel is promoted, startability is improved, and fuel saving and exhaust gas performance are improved. To do.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply control device for an internal combustion engine, and more particularly to an improved fuel supply control device for controlling fuel supply at the time of starting the internal combustion engine by using first and second starting pulses. It is about.

[0002]

2. Description of the Related Art FIG. 9 is a diagram showing a schematic structure of an internal combustion engine disclosed in, for example, Japanese Patent Publication No. 59-51662 and a block diagram of a conventional fuel supply control device. In the figure, reference numeral 1 is an outer box of the Karman vortex generator, which allows air taken in by an internal combustion engine, which will be described later, to pass through. Reference numeral 11 is a vortex generator housed in the outer box 1, and 12 is a Karman vortex generated in the intake air by the vortex generator 11. Reference numeral 2 is a vortex detector, and reference numerals 21 and 22 are ultrasonic transmitters and ultrasonic receivers attached to the outer surface of the outer box 1, respectively. Vortex detector 2
Generates ultrasonic waves by driving the ultrasonic wave transmitter 21 by a built-in oscillation circuit (not shown). This ultrasonic wave is a vortex 1
After being frequency-modulated every time it occurs by 2 etc., it reaches the ultrasonic receiver 22. The vortex detector 2 detects the frequency-modulated ultrasonic wave with the ultrasonic wave receiver 22, demodulates the frequency change of the ultrasonic wave with an FM signal demodulator (not shown), and the downstream portion of the vortex generator 11. Karman vortex 12
The pulse train of the frequency corresponding to the generation frequency of is output.
Reference numeral 3 denotes an internal combustion engine used in an automobile, for example, and an outer case 1
And the air supplied through the intake air pipe 31 communicating therewith, and the fuel supplied from the fuel supply means provided in the intake air pipe 31, for example, a fuel supply solenoid valve (hereinafter referred to as an injector) 32. . Reference numeral 33 is a throttle valve provided in the intake air pipe 31, and adjusts the amount of air taken into the internal combustion engine 3. A fuel pump and a fuel pressure regulator (not shown) are connected to the injector 32, and the pressure difference between the pressure of the intake air pipe 31 and the fuel pressure supplied to the injector 32 is made constant. Reference numeral 34 denotes a temperature detecting means, such as a water temperature sensor, which is provided in the internal combustion engine 3 and detects the temperature of the cooling water thereof, such as a thermistor having a larger resistance as the temperature is lower. Reference numeral 35 is a spark plug which is provided in the internal combustion engine 3 and ignites it.
A battery 4 supplies electricity to each circuit described later. 5
Is a starter connected to the battery, for example, a starter switch. When turned on, the exciting coil 6 of a starter switch (not shown) is energized to rotate the internal combustion engine 3.
7 is an ignition coil connected to the battery 4, 8 is a point of a distributor (not shown) connected to the primary side of the ignition coil 7, and the secondary side of the ignition coil 7 is connected to the ignition plug 35. There is. Reference numeral 40 denotes a fuel supply controller connected to the output side of the vortex detector 2, the injector 32, the water temperature sensor 34, the start switch 5 and the ignition coil 7.

The fuel supply control device 40 detects a starting state in which the starting switch 5 is turned on and the rotational speed of the internal combustion engine 3 is below a predetermined value (for example, 400 rpm),
Only in this starting state, the injector 32 is driven in synchronization with the constant frequency of the pulse train output from the oscillator (not shown) incorporated in the fuel supply control device 40, and the internal temperature of the internal combustion engine 3 detected by the water temperature sensor 34 is detected. The lower the cooling water temperature, the longer the drive time width. Further, the fuel supply control device 4
When the starting switch 5 is turned off or the rotation speed of the internal combustion engine 3 exceeds the above-mentioned predetermined value, 0 drives the injector 32 in synchronization with the output frequency of the vortex detection device 2 and sets the driving time width to 0. It is changed according to the output of the water temperature sensor 34. As described above, the lower the cooling water temperature, the longer the drive time width.

FIG. 10 is a circuit diagram showing the detailed structure of the fuel supply control device 40 shown in block form in FIG. When the internal combustion engine 3 is ignited by the spark plug 35, the output of the operational amplifier OP1 becomes high level and the transistor Q1 is turned on for a certain period of time. After the transistor Q1 is turned off, the voltage input to the terminal + of the operational amplifier OP2 rises in proportion to the rotation speed of the internal combustion engine 3. Operational amplifier OP2
Since a voltage corresponding to a rotation speed of 400 rpm is set to the terminal-of the internal-combustion engine 3, the output of the operational amplifier OP2 is
When the number of rotations exceeds 400 rpm, the level becomes high and 40
It becomes low level below 0 rpm. The output of the transistor Q3 is at a low level while the start switch 5 is ON, and the output is OFF.
In case of high level. Therefore, the start switch 5
When it becomes N and the rotation speed is 400 rpm or less, the oscillator O
The SC outputs, for example, a pulse train having a constant frequency equal to the frequency of the pulse train output by the vortex detection device 2 when the internal combustion engine 3 is in the idle state, and this becomes the output of the OR gate G4. However, when the rotation speed exceeds 400 rpm or the start switch 5 is turned off, the output of the OR gate G4 becomes the output of the vortex detector 2. The output of the OR gate G4 becomes high level and the transistor Q4 is turned on for a certain time.
After that, when the transistor Q4 is turned off, the voltage input to the terminal-of the operational amplifier OP3 rises.

The output of the water temperature sensor 34 is the operational amplifier OP3.
It is input to the terminal + of. However, the start switch 5 is ON
When the rotation speed is 400 rpm or less and the transistor Q2 is OFF, the voltage obtained by dividing the output of the water temperature sensor 34 by the resistors R3, R4 and R5 is input to the terminal + of the operational amplifier OP3, and the start switch 5 is OFF. When the rotation speed exceeds 400 rpm, the transistor Q2 is turned on, so the voltage divided by the resistors R3 and R4 is input to the above-mentioned terminal +. Therefore, when the cooling water temperature of the internal combustion engine 3 decreases, the resistance value of the water temperature sensor 34 increases, the voltage of the terminal + of the operational amplifier OP3 increases, and the transistor Q2 turns off.
In this case, the voltage at the terminal + of the operational amplifier OP3 is higher than that in the case where the transistor Q2 is ON. The output of the operational amplifier OP3 becomes high level until the capacitor terminal voltage becomes higher than the voltage of the terminal + of the operational amplifier OP3 after the transistor Q4 is turned off, the transistor Q5 is turned on for that time, and the injector 32 is energized for that time. The fuel is supplied to the engine 3.

[0006]

Combustion in an internal combustion engine is caused by igniting a mixture of gasoline and air sucked into a cylinder. Therefore, it is necessary to form a good air-fuel mixture to obtain good combustion. At the time of starting, since the intake air pipe and the cylinder are cold, the gasoline injected from the injector is difficult to vaporize, and the state of the air-fuel mixture formed is not so good. In other words, the rate at which the fuel supplied from the injector is vaporized (atomized) and contributes to combustion is considerably worse at the time of start-up than at the time of non-start-up (normal operating state). Therefore, at the time of starting, it is necessary to supply more fuel than originally required. The vaporization (atomization) rate decreases as the internal combustion engine cools, that is, as the cooling water temperature decreases.

In order to improve the vaporization rate at the time of starting, there is a method of warming the internal combustion engine first and then starting the engine. In this case, the engine oil is also warmed, so that very good startability can be expected. . Such a method is conventionally used as a block heater in extremely cold regions such as Canada. However, this method has a problem that it is considerably expensive.

Further, the higher the driving frequency of the injector, the higher the vaporization rate, but it is necessary to reduce the pulse width of the injector as the frequency increases. this is,
This is because the fuel supplied to the cylinder is the product of the frequency and the pulse width, and the vaporization rate improves as the frequency increases, as described above, so that the fuel supply amount can be small. However, the pulse width of the injector cannot be shorter than the mechanical response of the injector, and this minimum pulse width is 1
It is about msec at 4V. Therefore, the conventional fuel supply control device described above with reference to FIGS. 9 and 10 has a problem that it is necessary to set the constant frequency of the oscillator so as not to become shorter than the minimum pulse width. Further, when the cooling water temperature is -10 degrees or lower, the fuel supplied to the internal combustion engine is 1
When the driving is performed once, the starting pulse width is about 100 to 200.
It is necessary to set msec, and at this time, if the minimum pulse width is 2 msec as described above, the constant frequency needs to be 50 Hz or less. However, when the cooling water temperature is -10 degrees or higher, the starting pulse width is 100 msec or less, so the minimum pulse width is 2
In order to secure msec, it is necessary to keep the constant frequency below 50 Hz. However, in the conventional device, since the injector was driven by the starting pulse of a constant frequency until the cooling water temperature of the internal combustion engine reached a certain high temperature, a trade-off between the starting property at an extremely low temperature and the minimum pulse width of the injector was performed. The constant frequency is about 30 Hz.

The present invention has been made in order to solve the above-mentioned problems, and improves the vaporization rate of the supplied fuel even when the cooling water temperature is low to improve the startability and to supply the fuel at the time of starting. An object of the present invention is to provide a fuel supply control device for an internal combustion engine, which can appropriately perform control and reduce fuel consumption.

[0010]

The invention according to claim 1 is
Start-up determination means for determining that the internal combustion engine is in a start-up state according to the open / closed state of the start-up means for starting the internal-combustion engine and the detection output of the rotation-angle detection means attached to the internal-combustion engine to detect the rotation angle A fuel supply unit that is attached to the internal combustion engine and that supplies fuel to the internal combustion engine when the internal combustion engine is started according to the detection output of the temperature detection unit that detects the temperature of the cooling water and the rotation angle detection unit. According to the output of the starting pulse width calculating means for calculating the widths of the first and second starting pulses to be driven, and the starting determining means and the starting pulse width calculating means, the temperature of the cooling water at the time of the starting is a predetermined temperature. If it is lower, the first start pulse having a high constant frequency and a short pulse width is generated, but if the temperature of the cooling water is higher than the predetermined temperature, the first start pulse is generated. Drive pulse generating means for generating the second start pulse having a frequency lower than the constant frequency and a pulse width longer than the pulse width and supplying the fuel to the fuel supply means in synchronization with the rotation of the fuel engine It is a thing.

The invention according to claim 2 is such that the starting pulse width calculating means can correct the pulse width of the first starting pulse in accordance with the rotational speed of the internal combustion engine. The invention according to claim 3 is such that the drive pulse generating means causes the switching from the first start pulse to the second start pulse in synchronization with the rotation of the internal combustion engine.

[0012]

According to the present invention, when the cooling water temperature at the time of starting the internal combustion engine is lower than the predetermined water temperature, the injector is driven by the first starting pulse having a constant frequency higher than the frequency at the time of starting the internal combustion engine. ON / OFF of injector
Is increased, atomization of fuel supplied from the injector is promoted, and startability is improved.

According to the second aspect of the present invention, the pulse width of the first starting pulse is reduced with an increase in the rotational speed of the internal combustion engine. Take control. Further, in the invention of claim 3, since the switching from the first starting pulse to the second starting pulse is performed in synchronization with the rotation of the internal combustion engine, the supplied fuel amount is appropriately controlled even at the time of switching. I can.

[0014]

【Example】

Example 1. FIG. 1 is a block diagram showing a schematic configuration of an internal combustion engine and an embodiment of the present invention.
6 to 31 to 34 are exactly the same as those in the conventional apparatus shown in FIG. 9a is a starter switch which is turned on by energizing the exciting coil 6 when the start switch 5 is turned on, and 9 is a battery 4 via the starter switch 9a.
Connected to the starter 10 for starting the internal combustion engine 3, 10 is an air cleaner attached to the intake air pipe 31 instead of the outer casing 1, 36 is a pressure sensor attached to the intake air pipe 31 to measure the pressure, and 37 Is a rotation angle detecting means, such as a crank angle sensor, which is attached to the internal combustion engine 3 and generates an output at each predetermined rotation angle.

A fuel supply control device 40A is connected to the pressure sensor 36, the water temperature sensor 34, and the crank angle sensor 37, and drives the injector 32 after completion of starting the internal combustion engine, that is, during normal operation, based on the detection outputs of these sensors. A drive pulse width calculation means 41 for calculating a pulse width, that is, a drive pulse width, a crank angle sensor 37, and a start switch 5, which are connected to the crank angle sensor 37 and the start switch 5 to determine the start state of the internal combustion engine 3 from the detected output and the open / closed state. Four
2, a crank angle sensor 37 and a water temperature sensor 34, and a start for calculating the widths of the first and second start pulses for driving the injector 32 when the internal combustion engine 3 is started, that is, the start pulse width, based on the detection outputs of these sensors. It is connected to the pulse width calculation means 43 and the drive pulse width calculation means 41, the start determination means 42 and the start pulse width calculation means 43, and generates a drive pulse having the pulse width calculated by the drive pulse width calculation means 41 during normal operation. Further, at the time of starting, the drive pulse generating means 44 for generating the first and second starting pulses having the pulse width calculated by the starting pulse width calculating means 43.
It has and.

FIG. 2 shows the fuel supply control device 4 shown in FIG.
0B is a block diagram showing a more specific configuration of the fuel supply control device 40B, in which each signal of the pressure sensor 36, the water temperature sensor 34, the crank angle sensor 37, and the start switch 5 is input to each cylinder of the internal combustion engine 3. The injector 32 provided for each is controlled. Further, the fuel supply control device 40B is a microcomputer corresponding to the drive pulse width calculation means 41, the start determination means 42, the start pulse width calculation means 43, and the drive pulse generation means 44 in FIG.
It is realized by 60). In addition, this C
The PU 60 has a ROM 61 and a RAM 62.

Reference numeral 51 is a filter, the input side of which is connected to the pressure sensor 36 and the output side of which is connected to the CPU 60 via the A / D converter 52. 53 is an interface, the input side of which is connected to the water temperature sensor 34 and the output side of which is connected to the CPU 60 via the A / D converter 54. Reference numeral 55 is a waveform shaping circuit, the input side of which is connected to the crank angle sensor 37 and the output side of which is directly connected to the interrupt input terminal P1 of the CPU 60 and is also connected to the CPU 60 via the counter 56. 57 is a timer CPU
It is connected to the interrupt input terminal P2 of 60. 58 is A /
D converter connected to the battery 4 and A / D
The converted result is output to the CPU 60. Reference numeral 59 denotes an interface, the input side of which is connected to the start switch 5 and the output side of which is connected to the input terminal P3 of the CPU 60. A timer 63 converts the output of the CPU 60 into a pulse width and outputs the pulse width to the driver 44. This driver 44
The injector 32 is driven. An oscillator (not shown) is connected to the input side of the counter 56 and the timers 57 and 63.

Next, the fuel supply control device 40 having the above-mentioned structure
The operation of B will be described. The pressure in the intake air pipe 31 of the internal combustion engine 3 is detected by the pressure sensor 36, the detected output is smoothed by the filter 51, converted into a digital value by the A / D converter 52, and taken into the CPU 60. The temperature of the cooling water of the internal combustion engine 3 is detected by the water temperature sensor 34, and the detection output is converted into a voltage by the interface 53,
A / D converter 54 converts the digital value to CPU 6
It is taken into 0. The battery voltage is converted into a digital value by the A / D converter 58 and taken into the CPU 60.
The rotation speed of the internal combustion engine 3 is detected by the crank angle sensor 37, and its detection output is shaped by the waveform shaping circuit 55,
It is input to the interrupt input terminal P1 of the CPU 60 and the counter 56. The CPU 60 performs an interrupt process at each rising edge of the output signal of the crank angle sensor 37, and then the counter 5
6 detects the period between the rising edges of the output signal of the crank angle sensor 37. The timer 57 generates an interrupt signal to the interrupt input terminal P2 of the CPU 60 every predetermined time (for example, 1 msec cycle). The CPU 60 creates various times by a program based on the interrupt signal from the interrupt input terminal P2. The ON signal and the OFF signal of the start switch 5 are converted into digital signals by the interface 59 and then the CPU 6
0 is input to the input terminal P3, and the CPU 60 determines from the digital signal and the crank angle sensor output signal described above whether the internal combustion engine 3 is in the starting state. CPU
Reference numeral 60 calculates the amount of fuel to be supplied to the internal combustion engine 3 based on the above signals, calculates the pulse width and drive timing of the pulse that drives the injector 32, and sets the value corresponding to the above pulse width in the timer 63. To do. Furthermore, CPU
60 triggers the timer 63 to trigger the timer 63
A pulse is generated in the driver, the pulse is amplified by the driver 64, and the injector 32 is driven.

Next, the operation of the CPU 60 will be described with reference to the flow charts and timing charts of FIGS.

FIG. 3 is a flow chart of the main program stored in the ROM 61 of the CPU 60.
When a reset signal from a power supply reset circuit (not shown) is input to 60, the program starts.

In step 100, the data in the RAM 62, the input / output port of the CPU 60, etc. are initialized. Next, in step 101, the output of the interface 53 (the output signal of the water temperature sensor 34) is digitally converted by the A / D converter 54 and stored in the storage location WT (not shown) of the RAM 62. Next, at step 102, the battery voltage is digitally converted by the A / D converter 58 and stored in the RAM 62 storage location VB.
(Not shown).

Next, in step 103, 30 / TR is calculated based on the cycle of the crank angle sensor 37 stored in the storage location TR (not shown) of the RAM 62 using the interrupt program described later, and rotation is performed. Get the number Ne. Next, at step 104, the load data P stored in the RAM 62 is calculated by using the rotation speed Ne and an interrupt program described later.
The data of the table Kp as shown in FIG. 4 stored in the ROM 61 at b is interpolated to obtain the basic driving time coefficient Kp (Ne, P
Calculate b). Next, in the WT (water temperature), the ROM 61
The data of the table f ₁ having the characteristics as shown in FIG. 5 (a) stored in is interpolated to calculate the water temperature correction coefficient f ₁ (WT),
The calculation of K _I = Kp (Ne, Pb) × f ₁ (WT) is performed, and the result is stored in the memory location K _I (not shown) of the RAM 62 as the driving time. Here, the basic driving time coefficient Kp (Ne, Pb) and the water temperature correction coefficient f ₁ (WT) are determined in advance by an experiment, and the basic driving time coefficient Kp (Ne,
Pb) is a coefficient obtained from the drive time width of the injector 32 in which the air-fuel ratio becomes the optimum value when the internal combustion engine 3 is completely warmed. In addition, the water temperature correction coefficient f ₁ (W
T) is a coefficient for increasing the driving time as the water temperature is lower, so that the internal combustion engine 3 can be stably operated in a state where the internal combustion engine 3 is not warm.

In step 105, the table f ₂ stored in the ROM 61 is interpolated with the above WT (water temperature) to calculate the starting basic drive time coefficient f ₂ (WT). And
Next, the table f ₃ stored in the ROM 61 is interpolated with the rotation speed Ne, the rotation speed correction coefficient f ₃ (Ne) is calculated, and then the f ₂ (WT) is multiplied. Furthermore, a coefficient (Ne / 3 for correcting the increase of the fuel supply amount according to the rotation speed Ne)
0) / 50 is multiplied to obtain the starting drive time T _C1 when the injector 32 is driven by the first start pulse having a constant frequency. That is, T _C1 = f ₂ (WT) × f ₃ (Ne) ×
(Ne / 30) / 50. Here, as shown in FIG. 5 (b), the basic driving time coefficient f ₂ (WT) at the time of starting has a characteristic that it decreases with an increase in the water temperature. Increase the rate of vaporization.
Further, the rotation speed correction coefficient f ₃ (Ne) has a characteristic that it decreases as the rotation speed Ne increases, as shown in FIG. 5 (c). The increase in the flow velocity of the intake air passing through and the amount of heat generation due to the compression pressure in the cylinder of the internal combustion engine 3 cause the rotation speed Ne of the internal combustion engine 3 to increase.
This is because the rate of vaporization of the supplied fuel increases as the rotational speed Ne increases. The coefficient (Ne / 30) / 50 is a driving time when the injector 32 is driven with the first starting pulse having a constant frequency as the starting driving time T _C1. The supply fuel is increased according to the increasing air amount. This coefficient (Ne / 30) / 50 is the case where the frequency of the first starting pulse for driving the injector at the time of starting the internal combustion engine 3 of four cylinders is 50 Hz, and this coefficient also changes if the number of cylinders or the starting pulse frequency changes. There is a need. In step 106, the basic drive time coefficient f ₂ (WT) at the start is multiplied by the rotation speed correction coefficient f ₃ (Ne) to obtain RA.
The data is stored in the memory location T _CL (not shown) of M62.

In step 107, the starting basic drive time T _C2 when the injector 32 is driven by the second start pulse synchronized with the rotation of the internal combustion engine 3 is calculated from the table f ₂ based on the water temperature WT.

In step 108, the dead time T _D of the injector 32 is calculated from the table f ₄ and the battery voltage V _B. Here, the characteristic of the table f ₄ is V as shown in FIG.
_This property is inversely proportional to _B.

Next, in step 109, the rotation speed Ne is compared with a predetermined value Nc, and if the rotation speed Ne is smaller than the predetermined value Nc, it is determined in step 110 whether the starting switch 5 is ON or OFF. At this time, the rotation speed Ne is a predetermined value Nc (for example, 4
00 rpm) or more, or if the start switch 5 is OFF, the start flag is cleared (numerical value O) in step 111. On the other hand, when the rotation speed Ne is smaller than the predetermined value Nc and the start switch 5 is ON, the start flag is set (numerical value 1) in step 112. After that, again step 101
Then, the same processing as above is repeated.

FIG. 6 is a flowchart of an interrupt program processed by the CPU 60 in synchronization with the output of the timer 57 every 1 msec. First, in step 200, the pressure sensor 36
After smoothing and A / D conversion, the output of is stored in the storage location Pb ₁ (not shown) of the RAM 62. In step 201,
The above-mentioned Pb ₁ is added to the A / D converted previous value Pb (t-1) of the pressure sensor 36, which has been integrated until the timer 57 outputs this time, to obtain a new integrated pressure value Pb (t).

In step 202, the number of times Np of the above integration is performed.
Is counted up once to obtain a new cumulative number Np.
In step 203, a timer for every 20 msec is created by counting the number of times by software based on the output of the timer 57 and the data in the RAM 62, and it is determined every 20 msec whether or not the processing of step 204 and the following steps is performed.

In step 204, it is discriminated whether the injection mode is rotation-synchronized or constant frequency drive. If the injection mode is constant frequency mode, the routine proceeds to step 205. The injection mode is set by the process shown in FIG. 7, which will be described later. In step 205,
The start mode, which will be described later, is determined, and if it is a set (setting 1), the mode is the start mode, and the routine proceeds to step 206.

In step 206, if the integrated value ΣT _I of the driving time when the injector 32 is driven by the first starting pulse having a constant frequency is less than the value T _{C L} calculated in step 106 of FIG. 3, step 207 Proceed to. By the processing in step 206, it is possible to prevent an excessive fuel supply when the rotation speed suddenly drops or when the internal combustion engine is stopped.

In step 207, the drive time T at the time of starting is
Driving time T _I obtained by adding injector dead time T _D to _C1
Is set in the timer 63, and the driving time T is set in step 208.
Add _I to ΣT _I. Finally, in step 209, the timer 63 is started to drive the injector 32 with the first start pulse. In steps 203 to 209,
20 msec when the injection mode is a constant frequency in the start mode
The first with a pulse width of T _I = T _C1 + T _D every (50 Hz)
The injector 32 is driven by the starting pulse of.

FIG. 7 is a flowchart of the processing performed by the CPU 60 in synchronization with the output of the crank angle sensor 37. In step 301, the output cycle of the crank angle sensor 37 is measured by the counter 56, and the value is stored in the storage location TR (not shown) of the RAM 62. Step 302
Then, it is determined whether or not the crankshaft has rotated twice, and this is performed by counting the output of the crank angle sensor 37. For example, in a 4-cylinder internal combustion engine 3, a crank angle sensor 3
7 is output for each 180 ° of the crankshaft, steps 303 to
The process of 310 is performed.

In steps 303 to 305, the water temperature (W
When T) is equal to or lower than t ° C (for example, -15 ° C), the injection mode is set to the constant frequency mode, and otherwise the rotation mode is set.

Steps 306 to 308 check the start flag set in FIG. 3, and if it is set (1
If the start flag is cleared, the start mode is cleared (0).
Set). Therefore, the injection mode and the starting mode described above are performed for each revolution of the crankshaft.

Next, in step 309, it is judged whether or not the crankshaft has made one revolution, and if it has made one revolution, step 31
At 0, the average value of the value Pb (t) of the pressure sensor 36, which has been A / D converted and integrated every 1 msec, is calculated from Pb (t) / Np and stored in the storage location Pb (not shown) of the RAM 62. . In step 311, the integrated value Pb (t) of the A / D converted values of the pressure sensor 36 and the integrated number Np are cleared.
That is, in steps 310 and 311, the crankshaft 1
The average value of the pressure sensor 36, which is sampled every 1 msec during the rotation, is calculated. If the crankshaft has not rotated 1, or if the above-mentioned Pb (t) and N _p is cleared the integrated value of the drive time T _I of the case of driving the injector 32 at a constant frequency mode proceeds to step 312 Clear ΣT _I. Therefore, ΣT _I is cleared in synchronism with the output of the crank angle sensor 37, and is the integration of T _I of the output of the crank angle sensor 37.

Next, steps 313, 314 and 315
Then, when the starting mode is set and the injection mode is on the rotating side, the pulse width T _I = T _C2 + T _D is calculated, and the pulse width of the second starting pulse is calculated. And step 318
In the timer 63 sets the T _I, to drive the injector 32 in the second starting pulse by starting the timer 63. That is, at the time of starting and when the water temperature (WT) is equal to or higher than t ° C., the injector 32 is driven by the second starting pulse having the pulse width T _I = T _C2 + T _D in synchronization with the output of the crank angle sensor 37. It

Next, in steps 313, 316, and 317, when the starting mode is not set, that is, after the completion of starting, the pulse width T _I = Pb × K _I + T _D is calculated, and the timer 63 is entered in step 318. The above T _I is set, the timer 63 is started, and the above pulse width T _I = Pb
The injector 32 is driven by the drive pulse having × K _I + T _D. Therefore, steps 313, 316, 317, 3
By 18, the intake air amount of the internal combustion engine 3 is calculated from the output of the pressure sensor 36 and the injector 32 is driven by the above-described drive pulse for each rotation of the crankshaft except when starting.

FIG. 8 is a chart showing the timing of the first and second starting pulses for driving the injector 32. (a) shows the output signal of the crank angle sensor 37, (b) shows the first and second starting pulses, and (c) shows the temperature of the cooling water of the internal combustion engine 3.

When the temperature of the cooling water is lower than the predetermined value t ° C. at the time of starting, the injector 32 is driven by the first starting pulse P1 every 20 msec, but after exceeding the predetermined value t ° C., the crank angle sensor 37 is driven. The injection mode is switched in synchronism with the output signal of, and thereafter, the injector 32 is driven by the second start pulse P2 every one rotation of the crankshaft of the internal combustion engine 3.

In the above description, the fuel supply control is performed by the pressure of the intake air pipe 31 of the internal combustion engine 3 and the rotation speed of the internal combustion engine 3. However, this control is also performed when the air flow sensor is used. The invention can be applied. Moreover, although the case where a plurality of injectors 32 are simultaneously driven has been described, the present invention can be applied to the case of sequential driving.

[0041]

As described above, according to the first aspect of the invention, the open / close state of the starting means for starting the internal combustion engine and the detection output of the rotation angle detecting means attached to the internal combustion engine to detect the rotation angle thereof. According to the detection output of the start determination means for determining that the internal combustion engine is in a starting state according to the, the temperature detection means attached to the internal combustion engine to detect the temperature of the cooling water and the rotation angle detection means A starting pulse width calculating means for calculating widths of first and second starting pulses for driving a fuel supply means for supplying fuel to the internal combustion engine at the time of starting the internal combustion engine; Depending on the output of the means, when the temperature of the cooling water is lower than a predetermined temperature at the time of starting, the first starting pulse having a high constant frequency and a short pulse width is generated. When the temperature of the cooling water is higher than the predetermined temperature, the second start pulse which is synchronized with the rotation of the internal combustion engine and has a frequency lower than the constant frequency and a pulse width longer than the pulse width is generated. Since it is provided with a drive pulse generating means for supplying to the fuel supply means, when the cooling water temperature at the time of starting the internal combustion engine is low, in order to drive the injector with the first starting pulse of a high constant frequency, The atomization of the fuel supplied from the injector is promoted, and the startability is improved. Further, as a result, the internal combustion engine can be started with less fuel compared to the case where the fuel at the time of starting is supplied in synchronization with the rotation of the internal combustion engine, which is effective in saving fuel and improving exhaust gas performance.

Further, according to the invention of claim 2, the pulse width of the first starting pulse can be corrected in accordance with the rotational speed of the internal combustion engine, so that the fuel amount is corrected in accordance with the change in the rotational speed of the internal combustion engine. However, there is an effect that proper fuel control can be performed even at the time of starting.

Further, according to the third aspect of the present invention, the switching from the first starting pulse to the second starting pulse is performed in synchronization with the rotation of the internal combustion engine. The effect that it can control is produced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an internal combustion engine and showing an embodiment of the present invention.

FIG. 2 is a block diagram showing details of a fuel supply control device in the present invention.

FIG. 3 is a flowchart of a main program of the fuel supply control device of the present invention.

FIG. 4 is a table of basic driving time coefficients stored in the fuel supply control device of the present invention.

FIG. 5 is a diagram showing various characteristics (f _{1 to} f ₄ ) stored in the fuel supply control device of the present invention.

FIG. 6 is a flowchart of an interrupt program of the fuel supply control device of the present invention.

FIG. 7 is a flowchart of processing performed in synchronization with a crank angle sensor output of the fuel supply control device of the present invention.

FIG. 8 is a timing chart of first and second starting pulses in the present invention.

FIG. 9 is a block diagram showing a schematic configuration of an internal combustion engine and a conventional fuel supply control device.

FIG. 10 is a circuit diagram showing a detailed configuration of the conventional fuel supply control device shown in FIG.

[Explanation of symbols]

 3 Internal Combustion Engine 5 Start Switch 32 Injector 34 Water Temperature Sensor 37 Crank Angle Sensor 40A, 40B Fuel Supply Control Device 42 Start Determination Means 43 Start Pulse Width Calculation Means 44 Drive Pulse Generation Means

Claims (3)

[Claims] 1. A starting means for starting an internal combustion engine, a fuel supply means for supplying a fuel to the internal combustion engine, a temperature detecting means attached to the internal combustion engine for detecting a temperature of cooling water thereof, the internal combustion engine In the internal combustion engine, which is provided with a rotation angle detecting means for detecting a rotation angle thereof, the internal combustion engine is in a starting state according to an opening / closing state of the starting means and a detection output of the rotation angle detecting means. The start determination means for determining that the first and second start pulse widths for driving the fuel supply means at the time of starting the internal combustion engine are set according to the detection outputs of the temperature detection means and the rotation angle detection means. When the temperature of the cooling water is lower than a predetermined temperature at the time of starting, according to the start pulse width calculating means for calculating and the outputs of the start determining means and the start pulse width calculating means. Generates the first starting pulse having a high constant frequency and a short pulse width, but when the temperature of the cooling water is higher than the predetermined temperature, is synchronized with the rotation of the internal combustion engine and is higher than the constant frequency. A drive pulse generating means for generating the second starting pulse having a low frequency and a pulse width longer than the pulse width and supplying the second starting pulse to the fuel supply means. . 2. A starting means for starting an internal combustion engine, a fuel supply means for supplying fuel to the internal combustion engine, a temperature detecting means attached to the internal combustion engine for detecting a temperature of cooling water thereof, the internal combustion engine In the internal combustion engine, which is provided with a rotation angle detecting means for detecting a rotation angle thereof, the internal combustion engine is in a starting state according to an opening / closing state of the starting means and a detection output of the rotation angle detecting means. The start determination means for determining that the first and second start pulse widths for driving the fuel supply means at the time of starting the internal combustion engine are set according to the detection outputs of the temperature detection means and the rotation angle detection means. When the temperature of the cooling water is lower than a predetermined temperature at the time of starting, according to the start pulse width calculating means for calculating and the outputs of the start determining means and the start pulse width calculating means. Generates the first starting pulse having a high constant frequency and a short pulse width, but when the temperature of the cooling water is higher than the predetermined temperature, is synchronized with the rotation of the internal combustion engine and is higher than the constant frequency. Drive pulse generating means for generating and supplying the second starting pulse having a low frequency and a pulse width longer than the pulse width to the fuel supply means, wherein the starting pulse width calculation means includes the first pulse 2. The fuel supply control device for an internal combustion engine, wherein the pulse width of the starting pulse can be corrected according to the rotational speed of the internal combustion engine. 3. Starting means for starting an internal combustion engine, fuel supply means for supplying fuel to the internal combustion engine, temperature detection means mounted on the internal combustion engine for detecting the temperature of cooling water thereof, and the internal combustion engine. In the internal combustion engine, which is provided with a rotation angle detecting means for detecting a rotation angle thereof, the internal combustion engine is in a starting state according to an opening / closing state of the starting means and a detection output of the rotation angle detecting means. The start determination means for determining that the first and second start pulse widths for driving the fuel supply means at the time of starting the internal combustion engine are set according to the detection outputs of the temperature detection means and the rotation angle detection means. When the temperature of the cooling water is lower than a predetermined temperature at the time of starting, according to the start pulse width calculating means for calculating and the outputs of the start determining means and the start pulse width calculating means. Generates the first starting pulse having a high constant frequency and a short pulse width, but when the temperature of the cooling water is higher than the predetermined temperature, is synchronized with the rotation of the internal combustion engine and is higher than the constant frequency. Drive pulse generating means for generating and supplying the second starting pulse having a low frequency and a pulse width longer than the pulse width to the fuel supply means, wherein the drive pulse generating means comprises: A fuel supply control device for an internal combustion engine, wherein switching from a starting pulse to the second starting pulse is performed in synchronization with rotation of the internal combustion engine.