JPS59134363A - Fuel feeder for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve operational performance under cooling or acceleration, by continuously feeding fuel through second injection valve at the downstream of throttle valve toward the heating face of a suction heater under low cooling water temperature or acceleration. CONSTITUTION:When the engine cooling water temperature is lower than 60 deg.C, for example, an electric heater 11 will function by a signal from a water temperature sensor 10 to heat the heating face 11a while when it is lower than 40 deg.C, required amount of fuel is fed continuously through second injector 13 provided at the downstream of a throttle valve 8 toward the heating face 11a to perform fuel spray effectively. Upon exceeding of cooling water temperature above 40 deg.C, fuel supply through second injector 13 is stopped to feed fuel intermittently through first injector 12 immediately above the throttle valve 8. Under acceleration and any cooling water temperature, all fuel is fed through second injector 13 to improve fuel response. Consequently operationability under cooling or acceleration can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply system for an internal combustion engine, and more particularly to a system for improving fuel atomization and acceleration.

Conventionally, in internal combustion engines equipped with fuel supply systems using single-injection valve or multiple-injection valve type fuel injection, fuel atomization is poor when the engine is cold or immediately after engine startup before warming up (hereinafter referred to as "cold time"). As a result, a mixture that is leaner than the set value is formed and supplied to the engine. This has the disadvantage that the smooth operation of the engine is impaired. As a countermeasure for this, on the intake passage leading to the engine,
It has been previously proposed to install an electric heating element for fuel*-1 atomization. However, with this method as well, the injector is installed upstream of the throttle valve, and a portion of the fuel supplied when the engine is cold as described above adheres to the wall of the throttle valve, throttle pod, etc. in the form of a liquid film. . As a result, it is not possible to sufficiently atomize all the fuel. In addition, in the single injection valve system, there is a problem in that the intermittent fuel supply method during acceleration, regardless of whether the engine is hot or cold, results in poor fuel response and a delay in the build-up of torque, etc.

Therefore, in view of the above problems, the present invention continuously supplies fuel from the second injector provided downstream of the throttle valve during cold and acceleration, and during warm-up (hereinafter referred to as hot time), fuel is continuously supplied from the second injector provided at the downstream of the throttle valve. - The aim is to improve fuel atomization and acceleration by intermittently supplying fuel from the first injector provided upstream of the fuel valve.

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a schematic diagram showing an intake manifold for a four-cylinder engine. Intake passage 9a (No. 1 = No. 2 cylinder), 9.
b (No. 3 and No. 4 cylinders), and has a substantially symmetrical shape. Fuel is supplied from upstream of the intersection of base lines AA and BB, passes through intake passages 9a and 9b, and is supplied to an internal combustion engine (not shown). FIG. 2 is a schematic diagram showing the configuration of the second injector. Solenoid coil 13a, plunger 13b, pipe 13C, connector 13d, case 13
e, stay 131. It is composed of a nozzle section 13b. When current flows through the solenoid coil 13a, the plunger 13b is pushed against the spring 13f and moves to the left in the figure. As a result, the liquid passes through the inside of the valve portion 13g, valve seat 13h, etc. and is injected by the nozzle portion 13. Solenoid coil 13
When the input a is cut off, the plunger 13b moves to the right in the figure by the spring 13f, and the valve portion 13g and the valve seat 1311
Stops the inflow of fuel. Therefore, the opening area between the valve portion 13g and the valve seat 13h can be varied by the input to the solenoid coil 13a, so that fuel can be controlled.

FIG. 3 shows a schematic diagram of the installation in the second injector. The cross section in FIG. 3 is a sectional view based on the A-A baseline of the intake manifold 9 shown in FIG.
There is an engine (not shown) on the left side. A throttle valve 8 is installed on the throttle body 7, and bolts (not shown) are installed on the throttle body 7.
It is assembled with wasoshiko etc. A heating surface 11a of the electric heating body 11 is formed as a riser portion 9C of the intake manifold 9. The electric heating body 11 includes a PTC element 1.
1b, a positive electrode plate 11C, a spring lid, etc., and a heating surface 11a of an electric heating element 11 is configured directly below the throttle valve 8. Throttle valve 8
A first injector (not shown) is installed upstream of the engine (always in an atmospheric state), and a second injector 13 is attached to the intake manifold 9. The intake manifold 9 is provided with a hole 9d through which the pipe 13e of the second injector 13 passes, and the stay 134 of the second injector 13 and the intake manifold 9 are assembled with the bolts 21 via the casket 20 to prevent leakage. It is attached. The nozzle part 13 provided at the tip of the pipe 13C of the second injector 13 is installed with respect to the heating surface 11a of the electric heating element 11, for example, ρ is 50 mm 1 J from the center, and θ is in the range of 20° to 90°. It is being

FIG. 4 is a schematic diagram showing an outline of the fuel supply device. Fuel is in the fuel tank 1. Filter 2. @Magnetic pump 3. It passes through the delivery vibe 4 and flows into the pressure regulator 5. During this time, the fuel pipe 1a.

Each is connected by 2a and 3a. When the fuel flowing into the constant pressure chamber 5d of the pressure regulator 5 exceeds the set force of the spring 5a provided in the diaphragm chamber 5C, the valve portion 5b moves upward in the figure and the outlet pipe 5
e. Returns to the fuel tank 1 through the fuel pipe 5f. Therefore, the pressure regulator 5 functions to maintain the pressure of the fuel pumped by the electromagnetic pump 3 at a constant level.

The first injector 12 is installed almost directly above the throttle valve 8 provided in the throttle tenon 7 (always in an atmospheric state). A water temperature sensor 10 is attached to the intake manifold 9 as a means for detecting a cold state, and an electric heating element 11 is installed directly below the throat/nottle valve 8 to improve fuel atomization. Heating surface 11a of electric heating body 11
? A second injector 13 is attached to the intake manifold 9 facing toward the intake manifold 9, and the fuel pipe 3b and the second injector 13 are connected. Slo Notrub f8
Opening degree detection means 8a for detecting the opening degree of the water temperature sensor-IJl
The detection signals such as the first one are input to the computer 15, and the first one.
Decide on the selection of the second injector 12.13. The computer 15 is an arithmetic circuit in the first injector. A rotation detecting means (not shown) for detecting the number of rotations of the engine 6 and a pressure detecting means for detecting intake negative pressure are configured as load detecting means for the engine 6.

Next, the operation of the above configuration example will be explained. In the case of cold (for example, when the engine cooling water temperature is lower than 60° C.), the electric heating element 11 is activated by a signal from the water temperature sensor 10 attached to the intake manifold 9 to heat the heating surface 11a. When the engine cooling water temperature is lower than, for example, 40°C, the entire amount of required fuel is continuously supplied to the heating surface 11a of the electric heating element 11 from the second injector 13 provided downstream of the throttle valve 8. Aiming for accurate fuel atomization. In this case, the nozzle part 1 of the second injector 13
3, if the mounting angle is less than 20" with respect to the heating surface Lla, the injected fuel may not be able to contact the heating surface 11b, so the mounting angle should be in the range of 20° to 90", and the distance should be within 501m. There is.

The fuel control method for the second injector 13 is based on signals from two detection means: a rotation detection means for detecting the rotation speed of the engine 6 (not shown) and a pressure detection means for detecting intake negative pressure.
As shown in the figure, since the opening area between the valve portion 13g and the valve seat 13h of the second injector [3] is increased or decreased, fuel can be controlled depending on the operating conditions. Therefore, the opening area of the valve portion 13g and the valve seat 13h is controlled by a signal from the computer 15 so that it is small when the load is low, and becomes large when the load is high.

When the engine cooling water temperature exceeds, for example, 40°C, the supply of fuel from the second injector 13 is cut off, and the first injector 12 provided directly above the throttle valve 8 is replaced.
Use a more intermittent (regular) fuel supply method. This is because the water temperature in the water channel 7a provided in the throttle body 7 has risen slightly since immediately after starting, so the wall temperature of the throttle body surface 7b is expected to increase fuel atomization. However, since fuel atomization is still not sufficient, the electric heating element 11 is operating.

Next, it is in a hot state (when the engine cooling water temperature is 60℃ or higher)
At this point, the electric heating element 11 stops operating. This is caused by an increase in water temperature in the waterway 7a of the throttle body 7 or the waterway 9e of the intake manifold 9, which causes the throttle pore surface 7b and the intake manifold inner wall 9c to rise.
This is because the fuel is heated and the atomization of the fuel is promoted. Under this condition, fuel is always intermittently supplied from the first injector 12. (However, during high rotations and high loads, continuous injection may be required due to the amount of fuel supplied.) Next, the case of acceleration will be explained. During acceleration, the opening detection means 8a detects the opening degree of the throttle valve 80 and the rotation speed detection means detects the rotation speed of the engine 6 (not shown). The injector 13 supplies all the fuel required.

This is to improve the responsiveness of the fuel. Therefore, the first
The second injector 12 and the second injector 13 are configured to be map-controlled depending on the operating state. With the above configuration, the fuel is sufficiently atomized when the engine is cold, which not only enables smooth operation of the engine, but also improves torque build-up during acceleration.

Next, the control circuit 15 will be explained with reference to FIG. Reference numeral 8a is a bulge meter attached in conjunction with the throttle, and the voltage corresponds linearly to the throttle opening.

150 is a differential circuit to which the movable terminal of the potentiometer 8a is connected. Then, S1, l sotol opening speed is output. FIG. 8 (A>. The non-inverting input of the comparator 160 is connected to the output of the differentiating circuit 150, and the constant voltage Vl is applied to the inverting input. When the output voltage of the differentiating circuit i50 becomes equal to or higher than the constant voltage V1, The output will be at a high level.

Figure 8(B). The input of the one-shot circuit 170 is connected to the output of the comparator 160, and the output is connected to the output of the R-S flip-flop circuit 190. The one-shot circuit generates a constant pulse when the output of the comparator 160 goes from a low level to a high level. Figure 8 (
C).

Then, the R-S flip-flop 190 is switched to change the output from high level to low level. Figure 8(D). 180
is a peak hold circuit and the R-S flip-flop 1
When the signal from 90 is high level, it is held, and when it is low level, the peak value is sampled. Figure 8(E). The integrating circuit 200 starts integrating when the signal from the R-S flip-flop 190 changes from a high level to a low level to generate a positive ramp waveform. Figure 8 (F).

210 is a comparator whose inverting input is connected to the output of the peak hold circuit 180, its non-inverting input is connected to the output of the integrating circuit 200, and the peak hold circuit 1
When the output voltage of the integrating circuit 200 becomes larger than the output voltage of the integrating circuit 80, the output becomes "1". The output of the comparator 210 is connected to the reset terminal of the R-S flip-flop 190, so when the output becomes "1", the R-S flip-flop
Integrating circuit 200 to reset Repflosop 170
is reset, the output becomes OV, and the output of the comparator 210 changes from "1" to "0". FIG. 8(C,).

The Q output of the R-S flip-flop 190 is shown in FIG. 8(D).
This pulse width is a value proportional to the output voltage of the peak hold circuit 180. In other words, the pulse width is proportional to the throttle opening speed.

On the other hand, 10 is a cooling water temperature sensor, which is composed of a thermistor whose resistance decreases as the water temperature rises. A resistor R is connected in series to one end of the thermistor, and a constant voltage V,
c is applied. The other end of the thermistor is grounded. The water temperature sensor 10 is also used as a main control circuit 13. The output of water temperature sensor 10 is connected to the non-inverting input of comparator 240.

A constant voltage V2 is applied to the inverting input of the comparator 240. When the water temperature is below the set temperature, the output of the comparator 240 is "1°", and when it exceeds the set temperature, the output is 0'. Q, and the other input is connected to the output of the comparator 240, and when the output of the R-S flip-flop 190 or the output of the comparator 240 is "1", "1'' is applied to the output. put out. 260
is a drive circuit that increases the power of the output of the OR gate 250 by +1.
1 to drive the second injector 13 and simultaneously drive the fourth injector 13.
The first injector 12 via the main arithmetic circuit 14 shown in the figure.
stop operating.

To summarize the above, when the throttle is depressed, the R-S flip-flop 190 generates a pulse with a time width corresponding to the depression speed, and the second injector 13
to drive. On the other hand, the second injector 13 is also driven when the cooling water temperature is below the set temperature.

The main calculation circuit 14 calculates the basic injection amount based on the intake pipe pressure and engine speed (not shown), and calculates the basic injection amount by correcting the basic injection amount by correction amounts such as cooling water temperature, idle link, intake temperature, power supply voltage, etc. The amount of radiation is determined and the first injector 12 is driven. The circuit structure is such that when the output of the control circuit 15 is "1", driving of the first injector 12 is stopped.

Next, FIG. 5 shows a second injector 1 as a second embodiment.
3 shows the installation. As in the first embodiment, the second injector 13 is attached to the intake manifold 9, but the direction of the vibrator 13C is changed to supply fuel to the heating surface 11a of the electric heating element 11. Further, the second injector 13 is connected to the throttle body 7.
It may be installed in If the second injector 13 cannot be installed at the cross-sectional location based on the A-A baseline of the intake manifold 9 shown in FIG. However, the effects of the present invention are not lost. Further, the second injector 13 may be attached at an angle θa of 45° or less with respect to the A-A baseline of the intake manifold 9 in FIG.

Furthermore, as shown in FIG. 6, an electric heating element 30 is installed between the intake manifold 9 and the intake manifold 9, and in the case of the electric heating element 30 having a heating diameter approximately equal to the throttle bore, The injector 13 is attached to the throttle body 7 so that the nozzle part 13k faces the heating surface 30a. Therefore, a similar mounting method can be considered even for a honeycomb-shaped electric heating element. In addition, a new fuel passage is created in the throttle body, intake manifold, etc. instead of the second injector 13, and an ON-OFF control valve that opens and closes the fuel passage is installed in the middle of the passage, making it easy to supply fuel. It is possible.

Air amount detection means is L Gesotro method (air amount sensor),
Even if the method is a D-jet method (calculated from engine rotation speed - engine intake negative pressure) or the like, the effects of the present invention will not be eliminated. The second injector is a Chesotoro continuous injection valve.

It may also be used as a fuel supply device.

As described above, the present invention provides a first valve upstream of the throttle valve.
In an internal combustion engine, a second injection valve is provided downstream of a throttle valve, and an intake air heating device is provided on an intake passage. Based on a signal from a cold state detection means that detects a cold state based on the cooling water temperature, when the cooling water temperature is lower than a set value or when accelerating, the second injection valve continuously injects air into the heating surface of the intake air heating device. This fuel supply system for internal combustion engines is characterized by supplying fuel to the injector and intermittently supplying fuel from the first injector when the cooling water temperature is higher than a set value, improving driveability when cold or accelerating. It has this excellent effect.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the intake manifold, Fig. 2 is a longitudinal sectional view of the second injector, Fig. 3 is a diagram showing the installation of the second injector, Fig. 4 is a schematic diagram of the fuel supply system, and Fig. 5 is a diagram of the installation of the second injector. The installation diagram of the second injector in the second embodiment is shown in the figure, Figure 6 is the installation diagram of the second injector in the third embodiment, Figure 7 is the circuit diagram of the control circuit, and Figure 8 is the timing showing the operation of each part of the control circuit. Char I. 1...fuel*-1 tank, 2...filter, 3...
Electromagnetic pump, 4...Delivery pipe, 5...Pressure regulator, 6...Engine, 7...Throttle body, 8...S1:I sotol valve, 9...Intake manifold, 10... - Ice temperature sensor, 11... Electric heating element, 12... First injector, 13... Second injector, 14... Main calculation circuit, 15... Control circuit. Representative Patent Attorney Takashi Okabe 1 Figure 2 Animals: 1 40 Figure 3 Figure 5 Figure 4 Figure 1 Figure 6 (H)

Claims (1)

[Claims] Load state detection for detecting the load state of an internal combustion engine in an internal combustion engine that includes a first injection valve upstream of a throttle valve, a second injection valve downstream of the throttle valve, and an intake air heating device on an intake passage. When the cooling water temperature is lower than a set value or during acceleration, the heating surface of the intake air heating device is injected into the heating surface of the intake air heating device from the second injection valve when the cooling water temperature is lower than a set value or when the engine is accelerated. 1. A fuel supply system for an internal combustion engine, characterized in that the fuel is continuously supplied to the fuel injection valve, and the fuel is intermittently supplied from a first injection valve when the cooling water temperature is higher than a set value.