JPH0242166A - Fuel control device for carburetor - Google Patents

Abstract

PURPOSE:To properly control the mixing ratio of fuel even when the negative pressure in an intake pipe coincides with the atmospheric pressure by controlling a solenoid valve in response to engine parameters and injecting fuel into the intake passage of a carburetor through a nozzle. CONSTITUTION:A throttle piston 2 fitted with a needle 3 is arranged on a carburetor main body 1. In this case, a low-pressure injection nozzle 26 is arranged on the upstream side of the intake passage 1A of the carburetor main body 1, its fuel injection port is directed to the opening section 1C of a main fuel feed passage 1B. The low-pressure injection nozzle 26 is connected to a fuel tank 21 via a solenoid 25 on/off-controlling the fuel, a strainer 24, an accumulator 23 and a fuel pump 22. The solenoid 25 is driven and controlled by a microcomputer 31 via a driving circuit 37 based on various engine parameters 38-41. The fuel quantity injection through the low-pressures injection nozzle 26 is properly adjusted.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fuel control device for a carburetor, and in particular, it is capable of smoothly increasing the engine speed even when the throttle valve is suddenly opened at low speeds. This article relates to a fuel control device for a carburetor that can be used.

(Prior art) A carburetor has a simpler configuration and is less expensive than an electronic fuel injection device, but it uses the negative pressure generated inside the cylinder to bifurcate the fuel and supply the air-fuel mixture to the inside of the engine. Because this is a system, it is not possible to respond very accurately to small changes in exhaust temperature, intake air temperature, atmospheric pressure, engine load, etc.

In order to compensate for this drawback, for example,
The publication describes a technology in which a solenoid valve is installed in the fuel passage or air bleed passage of a carburetor, and the opening and closing of the solenoid valve is controlled according to various data to change the original mixture ratio of the carburetor. .

(Problems to be Solved by the Invention) The above-described conventional technology had the following problems.

In other words, for example, if the throttle valve is suddenly opened at low speed, the negative pressure in the intake pipe will almost match the atmospheric pressure, or in this case, the fuel stored in the float chamber of the carburetor will flow out of the carburetor. Since the air cannot be efficiently drawn into the intake passage, the engine speed cannot be smoothly increased.

The technology described in the above publication is for controlling the amount of fuel or air bleed by disposing a solenoid valve in the fuel passage or air bleed passage of the carburetor and controlling the drive of the solenoid valve. Even with this technique, in the case described above, fuel suction is not performed well, and the fuel mixture ratio cannot be appropriately controlled.

Therefore, the engine speed cannot be smoothly increased.

The present invention has been made to solve the above-mentioned problems.

(Means and operations for solving the problems) In order to solve the above-mentioned problems, the present invention provides a fuel injection nozzle disposed in the intake passage of a carburetor, and a fuel supply pump connected to the nozzle. The present invention is characterized in that a solenoid valve for controlling fuel supplied from the pump to the fuel injection nozzle is provided, and the solenoid valve is controlled according to engine parameters.

As a result, even if the negative pressure in the intake pipe is almost equal to atmospheric pressure, fuel is forcibly supplied into the intake pipe, so the fuel mixture ratio becomes an appropriate 9°, and the engine speed increases. can be raised smoothly.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention.

In FIG. 2, the main body 1 of the vaporizer includes a needle 3.
A throttle piston 2 is provided, and the throttle piston 2 is slidably controlled by a link device 2A. No. 71 No. 13 suppresses the piston valve hitting sound caused by intake pulsation by adjusting the throttle piston 2 and carburetor main body 1.
This is a slide plate that adjusts and reduces the gap between the inner wall and the inner wall.

Code 4. 5. 6. 7 and 8 are a main air jet, a first main air jet, a second main air jet, an air cleaner, and a main air bleed, respectively. Controlled by motion.

A solenoid 9 that controls the flow rate of air passing through the second main air jet 6 is controlled on/off based on data detected by various sensors. Since this control method is well known, its explanation will be omitted.

No. 71 1011 and 12 are slow jets, slow air jets, and slow air bleeds. Further, numerals 14 and 14A are the float chamber and the liquid level of the fuel.

A fuel injection port of the throttle piston 26 is located in the intake passage IA of the carburetor. This injection port is arranged so as to inject fuel toward the opening 1c of the main fuel supply passage IB.

This low pressure injection nozzle 26 is connected to a solenoid 2 that controls on/off the fuel to be injected from the low pressure injection nozzle 26.
5. It is connected to the fuel tank 21 via the strainer 24, the pressure accumulation chamber l<-23, and the fuel pump 22.

This fuel pump 22 may be either a negative pressure pump or an electromagnetic pump.

No. 71 31 is a microcomputer, which, as is well known, includes a CPU 32, a ROM 3, a RAM 34, an input/output interface 35, and a common bus 36 connecting them.
Consists of.

A drive circuit 37 that drives the solenoid 25, and a throttle opening sensor 38 that detects the opening θth of the throttle valve.
, a rotation speed sensor 39 that detects the engine rotation speed Nc, a neutral switch 40 that detects whether the transmission of the vehicle is in neutral, and a clutch switch 41 that detects whether the clutch is connected, respectively. It is connected to the input/output interface 35.

Note that the microcomputer 31 and the tsuta-ku operating circuit 3
7, etc. are integrated to form an electronic control device of the vehicle.

Next, the operation of one embodiment of the present invention will be explained. The operation of this embodiment is executed by the CPU 32 shown in FIG.

FIG. 3 is a flowchart showing the basic operation of an embodiment of the present invention, FIG. 4 is a flowchart showing details of subroutine S4 shown in FIG. 3, and FIG. 5 is a flowchart showing the details of the subroutine S4 shown in FIG. 3. It is a flowchart showing an operation that is executed at regular intervals (2 [m5eel)].

The operation shown in FIG. 3 is executed after the ignition switch of the vehicle is turned on.

In step S1 in FIG. 3, data on the throttle opening θth (data immediately before the ignition switch is turned off) stored in the microcomputer 31 is fetched.

Similarly, in steps S2 and S3, data on the engine rotational speed Ne and throttle opening degree θth immediately before the ignition switch is turned off are taken in.

In step S4, the operation of the solenoid 25 in FIG. 2 is controlled according to the engine parameters of the vehicle.

The process of step S4 is as shown in FIG.
First, in step Sll, the rate of change Δθth of the throttle opening θth is a predetermined rate of change Δθth.

It is determined whether or not the value is greater than or equal to the value. This throttle opening θ
The rate of change Δθth of th is detected by constant time interrupt control, which will be described later with reference to FIG.

The rate of change Δθth of the throttle opening θth is the predetermined rate of change Δ
If it is greater than or equal to θtho, flag FF2 is set to 0 in step S12. This flag FF2, as described later regarding steps S22 and S23,
It becomes 1 when the third map is read.

Next, in step S13, it is detected whether or not the transmission of the vehicle is in neutral. If it is in neutral, the process proceeds to step S15, and if it is not neutral, the process proceeds to step S14.

In step S14, it is detected whether or not the clutch is connected. If not, the process moves to step S15 (if the clutch is disengaged), and if the clutch is connected, the process moves to step S16.

That is, when the process proceeds to step S15, the vehicle is in an unloaded state, and when the process proceeds to step 316, the vehicle is in a loaded state.

In steps S15 and 316, the energization time Ta of the solenoid 25 corresponding to Δθtb (Δθthn) detected in the process of FIG.
(Fig. 2) +: Calculate using ZW and the calculated first map and second map.

FIG. 6.7 is a diagram showing the contents of the first and second maps.

The first map shown in FIG. 6 is for injecting fuel from the low-pressure injection nozzle 26 when the throttle valve is suddenly opened when the vehicle is in a no-load state. The second map shown in FIG. 5 is for when the vehicle is in a negative 6:1 state and fuel is injected from the low pressure injection nozzle 26 when the throttle valve is suddenly opened.

In the first and second maps, the energization time Ta of the solenoid 25 is set using the engine speed Nc and the rate of change Δθth of the throttle opening θtl+ as parameters.

In addition, in the first and second maps, the energization time Ta is set at the position where the lines constituting the map shown in FIG. 67 intersect.
is set. Therefore, if Δθth or engine speed Ne corresponding to this intersection is not detected, the energization time Ta is calculated by interpolation (for example, 4-point interpolation).

Note that Δθtho explained regarding step Sll above
are shown in FIGS. 6 and 7.

Returning to FIG. 4, in step S15 or S.16,
Once the energization time Ta has been determined, in step S17, whether the energization time T iL or the microcomputer 31
(FIG. 2) is stored in a register or the like.

Next, in step 318, the energization time Ta
It is determined whether or not is O. 1iJ T + when energized
If 1 is greater than 0, the process proceeds to step S19.
If it is 0, the process moves to step S22.

In step S19, it is determined whether the flag FFI is 1 or not. This flag FFI is initialized to O when the ignition switch is turned on, and then set to 1 in step S21, which will be described later.

If it is determined that the flag FFI is not 1, a predetermined count value (for example, 50) is set in the duty cycle counter in step S20.

This duty cycle counter will be described below with respect to FIG.

Then, in step S21, the flag FFI is set to 1.

If it is determined in step 318 that the energization time Ta is 0, the flag FF2 is set to 1 in step S22.

Next, in step S23, the throttle opening θt
h, and a solenoid 25 corresponding to the engine speed Nc.
The energization time Tb is determined using the third map stored in the ROM 33 (FIG. 2).

FIG. 8 is a diagram showing the contents of the third map.

The third map shown in FIG. 8 is for injecting fuel from the low-pressure injection nozzle 26 in accordance with the throttle opening θth and the engine speed Nc, regardless of the magnitude of Δθth. That is, in this third map, the energization time Tb of the solenoid 25 is set using the engine speed Ne and the throttle opening θtb as parameters.

Further, in this third map, similarly to the first and second maps, the energization time Tb is set at the position where the lines forming the map shown in FIG. 8 intersect. Therefore, the throttle opening degree θth (θihn
) or the engine speed Nc is not detected, the energization time Tb is calculated by interpolation (for example, 4-point interpolation).

In step S24, similarly to step S17, during the energization period Tb, the microcomputer 31
(FIG. 2) is stored in a register or the like.

After step S21 or S24, or step S1
After flag FF is determined to be 1 in step 9, the process ends.

Next, the operation shown in FIG. 5 will be explained. As described above, this fixed-time interrupt control is performed, for example, every 2[+n5ecl.

First, in step S31, the throttle opening degree θth
n is detected.

In step S32, the throttle opening degree θtbn-25 detected in this process 25 times before is subtracted from the detected throttle opening degree Othn, and the rate of change Δθth of the throttle opening degree is detected. In other words, this process is performed every 2 [m5cc], so the rate of change Δθ
th is 50 [throttle opening θth during m5ccl
is the changed value.

In step S33, it is determined whether the count value of the duty cycle counter is O or not. When the process shown in FIG. 5 is performed first after the ignition switch is turned on and the process shown in FIG. 4 is performed, the count value of the duty cycle counter is 50.

If the count value of the duty cycle counter is not O, the count value of the duty cycle counter is counted down by 1 in step S34.

Next, in step S35, it is determined again whether the count value of the duty cycle counter is 0 or not. If the count value of the duty cycle counter is 0, the flag FFI is set to 0 in step 33B. Then, in step S37, the same count value as the count value set in step 520 (FIG. 4) is set in the duty cycle counter.

Next, in step 338, 1. It is determined whether the count value of the on-time counter is O or not. The on-time counter is set to the energization time Ta or Tb stored in the register at step S17 or 524 (FIG. 4) in step S41, which will be described later.

If the count value of the on-time counter is 0, the process goes to step S41, and if the count value is not 0, the process goes to step S41.
The process moves to step S39.

In step S39, the count value of the on-time counter is counted down by one.

In step S40, it is determined again whether the count value of the on-time counter is 0 or not.

If the count value of the on-time counter is O, the process goes to step S41, and if the count value is not 0, the process goes to step S41.
The process moves to step S44.

In step S41, the energization time Ta or Tb stored in the register in step S17 or 524 (FIG. 4) is set in the on-time counter.

In step S42, it is determined whether the count value of the +Ir and on-time counter is O or not.

If the count value of the on-time counter is O, the process goes to step S43, and if the count value is not O, the process goes to step S43.
The process moves to step S44.

In step S44, the pump output is turned on, that is, the solenoid 25 (FIG. 2) is turned on, and fuel is injected from the low pressure injection nozzle 26. Conversely, in step S43, the pump output is turned off, that is, the solenoid 25 is turned off, and fuel injection from the low-pressure injection nozzle 26 is stopped.

After the process in step 343 or S44 is completed, 1 is added to n in step S45, and then the process ends.

If it is determined in step S33 that the count value of the duty cycle counter is O, the process moves to step S36.

If it is determined in step S35 that the count value of the duty cycle counter is not O, then in step S48 the count value of the on-time counter is set to 0.
It is determined whether or not.

If the count value is not 0, in step 5491, the count is counted down by 1 (1), and then the process moves to step S42.

If the count value is 0, it is determined in step 550 whether flag FF2 is 1 or not.

When the flag FF2 is 1, that is, when the previous energization of the solenoid 25 was performed using the energization time Tb read out from the third map, the process moves to step S43, and the solenoid 25 is turned off. If the flag is FF2 or O, the process moves to step S41, and the energization time Ta read from the first or second map is set in the on-time counter.

Now, to summarize the processing shown in Figure 4.5, first,
In the process of FIG. 4, if Δθtl+ is greater than or equal to ΔθIha, depending on whether the vehicle is under load or not,
The energization time Ta is read from the first or second map.

If this energization time TH1 is not 0, flag FF1
is set to 1, and 50 is set to the duty cycle counter. When the continuous 1"U time Ta is O, the flag FF2 is set to 1, and 181 Tb during energization is read from the third map.

In the process shown in FIG. 5, first, θth necessary for reading the third map is detected, and Δθth necessary for reading the first and second maps is detected. Although not shown in Figures 4 and 5, the engine rotation speed No. required for reading the first to third maps can be determined by determining the detection interval of the claws formed on the crankshaft of the engine. ,
Calculated.

The count value of the duty cycle counter is decremented by 1 each time this process is performed. In other words, if the process shown in FIG. 5 is performed every 2 [m5ce] and the duty cycle counter is set to 50, then the process from the time the duty cycle counter is set until the count value becomes 0 is The time is 100 [ms+30].

Further, the count value of the on-time counter is also decremented by 1 each time this process is performed. This on-time counter is
When the count value becomes O, unless the count value of the duty cycle counter is not O and the flag FF2 is 1, as shown in step S41, it is stored in step S17 or S24 of FIG. Energization time Ta
Or Tb is set in the on-time counter.

In other words, if the energization time Ta read from the first or second map is stored in the register, the on-time counter will be O regardless of whether the duty cycle counter count value is O or not. Then, the energization time T
il is set in the on-time counter, but if the energization time Tb read from the third map is stored in the register, the count value of the duty cycle counter is 0 and the on-time counter is O. Only if , then the time Tb is set in the on-time counter. In other words, when the solenoid 25 is energized only by the data stored in the third map, the cycle is 1.
00 [m5ec].

When the count value of this on-time counter is not 0, the solenoid 25 is turned on and fuel injection is performed from the low-pressure injection nozzle 26, and the count value is 0.
If so, fuel injection from the low pressure injection nozzle 26 is stopped.

Also, if only the energizing time Ta is read from the first or second map after the ignition switch is turned on and the energizing time Ta is not 0, or if the energizing time Tb is read from the third map. After that, only the energization time Ta is read from the first or second map, and the energization time Ta is read out from the first or second map.
If the flag FFI is not 0, the flag FFI is set to 1, and the duty cycle counter is set to 50. This setting is performed even if the count value of the duty cycle counter is not 0.

In other words, the setting of the energization time Ta (setting to the on-time counter) can be performed every 2 [m5cc], but the setting of the energization time Tb is only possible when Tb other than 0 is read out continuously. 100 [rasec] since the first Tb was read or the last time Ta was read.
] is carried out every. Then, the starting point of the cycle (100 [m5ec]) of this energizing time Tb is, if the energizing time Ta is continuously read from the first or second map and these energizing times Ta are not 0, Not changed.

Now, the process shown in FIG. 4 mentioned above is performed in step Sl.
l may be omitted and the process may be started from step S12.

FIG. 9 is a time chart showing an example of the operation of an embodiment of the present invention, in which (A) shows the throttle opening θtb, (
B) is the engine speed Ne, and (C) is the first or second
The current applied to the solenoid 25 based on the energization time Ta read from the map (D) is the current applied to the solenoid 25 based on the energization time Tb read from the third map. ) indicates the total current applied to the solenoid 25.

FIG. 1 is a functional block diagram of an embodiment of the present invention. In FIG. 1, the same reference numerals as in FIG. 2 represent the same or equivalent parts.

In FIG. 1, the output signal line of the throttle opening sensor 38 is connected to a Δθth calculation means 51.

The output signal lines of the Δθth calculating means 51 and the rotation speed sensor 39 are connected to a first map 54 and a second map 55, respectively.
It is connected to the. The first map 54 and the second map 55 are connected to the flip-flop 57 via the switching means 53.
It is connected to the set input terminal S of and the drive circuit 37.

The output signal lines of the throttle opening sensor 38 and rotation speed sensor 39 are further connected to a third map 56.

The Δθtl+ calculation means 51 calculates the latest throttle opening θth and the throttle opening θ 50 [m5ec] before.
Using th, calculate 80tb.

In this example, the neutral switch 40 and the clutch switch 41 each output a signal when the transmission of the vehicle is in the neutral state and when the clutch is in the disengaged state. This neutral switch 4
0 and the clutch switch 41 are connected to a control terminal of a switching means 53 via an OR gate 52.

The switching means 53 normally connects the second map 55 to the drive circuit 37 and the flip-flop 57, but when it receives the signals t and i output from the OR gate 52, it connects the second map 55 to the first map 54. Connected to drive circuit 37 and flip-flop 57.

Note that the OR gate 52 does not need to be provided (and the output lines of the neutral switch 40 and clutch switch 41 may be directly connected to the control terminal of the switching means 53.

The flip-flop 57 generates an output Q when a signal is input to the set input terminal S. This Q signal causes the timer 58 to measure 100 [apsccl, and after the measurement, a signal to that effect is sent to one input terminal of the AND gate 59 and the reset terminal R of the flip-flop 57.
Output to.

The third map 56 is connected to the other input terminal of an AND gate 59, and the output line of the AND gate 59 is connected to the drive circuit 37.

The energization time Tb read from the third map 56 or the energization time Ta read from the first map 54 or the second map 55 is manually input to the drive circuit 37, and the energization time Ta or TL) is Solenoid 25 is energized. Of course, when the energization time Ta or Tb is 0, the solenoid 25 is not energized.

Note that No. 71 100 indicates an electronic control device of the vehicle.

Now, the fuel injected from this low pressure injection nozzle 26 is
When the throttle valve is suddenly opened at low speed 1 (+7),
This is to increase the amount of fuel supplied to the engine from the carburetor, and it does not require much fuel injection, so the pressure given to the fuel is less than that of a typical electronic fuel injection nozzle. It does not need to be under high pressure like the fuel being supplied. Therefore, the low-pressure injection nozzle 26, the fuel pump 22, etc. can have a simplified configuration compared to a general electronic fuel injection nozzle, a fuel pump applied to the electronic fuel injection nozzle, etc. .

In addition, in the above description, the energization time of the solenoid 25 that controls the fuel ffi injected from the low-pressure injection nozzle 26 is determined by the engine speed NQ and the throttle opening θth.
It is set according to the engine speed Nc and the rate of change Δθth of the throttle opening θth. However, the present invention is not particularly limited to this, and may be set according to only one of the engine speed Nc and the throttle opening 6th, and the rate of change Δθth of the engine speed Nc and the throttle opening θth. It's okay.

Furthermore, engine speed Ne and throttle opening θtl
It has been explained that two types of maps (first and second maps) in which the + change rate Δθtl+ and the energization time Ta are associated are set depending on whether the vehicle is under load or not. Only one type may be set regardless of whether the vehicle is under load or not.

Conversely, a map in which engine speed Nc and throttle opening degree 0th are associated with 71 hours Tb corresponds to the +1
111 is negative;: Regardless of whether it is in the 1 state or not,
Although we have explained that only one type (third map) is set, depending on whether the +14 cars in question are under load or 100,
The type may be set.

In addition, although the energization time TfL and Tb have been described as being read from the first to third maps, the energization time can be calculated by changing the throttle opening θjh or the change in the opening θth using the engine speed No. as a parameter. The energization time T iL or Tb is set as a function of the rate Δθtb or a function of the engine rotation speed Ne with the throttle opening θtb or the rate of change Δθth of the opening θth as a parameter.
may be calculated.

Furthermore, the present invention arranges a low-pressure injection η/J nozzle in the intake passage of the carburetor, and fuel is injected from the low-pressure injection nozzle according to engine parameters such as the throttle opening θth, the rate of change of the opening θth Δθtl+, and the engine speed Nc. The fuel injection control method of this low-pressure injection nozzle is not limited to the one described above. The control method can be modified in various ways, but since these modifications can be easily created by those skilled in the art, a description thereof will be omitted.

Furthermore, for example, a solenoid 25 that can make the stroke of the plunger variable may be used, and the stroke of the plunger may be controlled in accordance with engine parameters.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

In other words, even if the negative pressure in the intake pipe is almost equal to the atmospheric pressure, fuel is forcibly injected into the intake pipe, so lj of air-fuel mixture at a predetermined mixture ratio can be supplied to the engine, and as a result, , it is possible to smoothly increase the rotational speed of the engine.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of an embodiment of the present invention. 3 to 5 are flowcharts showing the operation of one embodiment of the present invention. 6 to 8 are diagrams showing the contents of the first to third maps. FIG. 9 is a time chart showing an example of the operation of an embodiment of the present invention. 21...Fuel tank, 22...Fuel pump, 25.
...Solenoid, 26...Low pressure injection nozzle, 31...
・Microcomputer, 37...Drive circuit, 38・
... Throttle opening sensor, 39... Rotation speed sensor,
40... Neutral switch, 41... Clutch switch, 51... Δθtl+ calculation means, 53...
Switching means, 54... first map, 55... second map, 56... third map, 57... flip-flop, 58... timer, 59... ANDGATE agent patent attorney Michito Hiraki and 1 other figure 2-+ ,・1-8

Claims (1)

[Claims] (1) A fuel control device for a carburetor that detects an acceleration state of a vehicle and supplies fuel to an intake passage of a carburetor, comprising: a fuel injection nozzle disposed in the intake passage of the carburetor; and the fuel injection nozzle. a pump that supplies fuel to the fuel injection nozzle; a solenoid valve that is arranged between the fuel injection nozzle and the pump and controls the fuel injected from the fuel injection nozzle; 1. A fuel control device for a carburetor, comprising: control means for increasing or decreasing the amount of fuel.