JPS62174542A - Electronic control type fuel injector - Google Patents

Abstract

PURPOSE:To obtain a proper air fuel ratio even in the operation of an EGR by setting the map for the operation of EGR more finely in comparison with the map for the nonoperation of EGR, in the maps for determining the fundamental injection time. CONSTITUTION:The fundamental injection time is determined according to the intake pressure detected by an intake pressure sensor 2 and the number of revolution which is detected by a revolution sensor 7 from the maps previously memorization-set in a control circuit 8. Said maps are provided for the operation and nonoperation of an EGR, and selected according to the ON/OFF of a solenoid valve 15. Further, though the map is represented in two dimensions of the intake pressure and the number of revolution, the map for the operation of EGR is set finer on the intake pressure side than in the map for the nonoperation of EGR. Therefore, the fundamental fuel injection time for the operation of EGR in which the variation of the demanded fuel quantity for the intake pressure can not be made uniform can be properly set without increasing the memory capacity of the map.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electronically controlled fuel injection device provided for an internal combustion engine having an exhaust gas circulation device for recirculating exhaust gas to an intake pipe.

[Conventional technology]

Traditionally, internal combustion engines for vehicles have been equipped with an exhaust gas recirculation system (hereinafter referred to as EGR) that recirculates a portion of the exhaust gas to the intake pipe in order to reduce harmful components in the exhaust gas, especially NOx. There are many.

By the way, in internal combustion engines equipped with EGR, such as those that execute engine control by determining the amount of fuel from the fuel injection valve based on the intake pressure and rotation speed, when the exhaust gas is recirculated, the actual Since the intake pressure is detected to be higher than the intake pressure corresponding to the intake air amount by the amount of exhaust gas recirculation, there is a problem that proper fuel control cannot be obtained when EGR is activated.

For such problems, for example, Japanese Patent Application Laid-Open No. 60-81
In Publication No. 449, when EGR is not operating, fuel control is performed by determining the basic injection time from a map determined by intake pressure and rotational speed, and when EGR is operating, fuel control is performed by determining the basic injection time from this map. Fuel control is performed by correcting the basic injection time based on a correction factor determined from a map determined by the throttle valve opening and rotational speed.

[Problem that the invention seeks to solve]

However, as shown in the above publication, the configurations of the two maps, which are set respectively depending on when EGR is activated and when it is not activated, are the same, that is, the number of grid points for each parameter is set to be the same. In the case where the number of grid points is set to match when EGR is not operating, because the amount of exhaust gas recirculation and the actual intake air amount and ratio change greatly with changes in rotation speed when EGR is operating. When EGR is activated, the number of lattice points is insufficient, resulting in a large difference between the amount of fuel required by the engine when EGR is activated and the amount of fuel that is calculated and supplied. , there is a problem that the air-fuel ratio is greatly disturbed, and if the number of grid points is set to match the EGR operation so that the controllability during EGR operation is sufficiently good, the number of grid points in each map is become more,
A storage device (
A problem arises in that it is necessary to increase the capacity of the ROM.

Therefore, an object of the present invention is to provide an electronically controlled fuel injection device that can obtain a proper air-fuel ratio even when EGR is in operation, and that does not unnecessarily increase the capacity of a storage device that stores the map contents. It is to be.

[Means for solving problems]

In order to solve the above problems, in the first invention, the eighth
As shown in the figure, an intake pressure detection means for detecting the intake pressure of an internal combustion engine having EGR, a rotation speed detection means for detecting the rotation speed of the engine, a fuel injection valve for supplying fuel to the engine, and An electronic control device comprising a valve opening time calculation means that determines a basic injection time according to the intake pressure and rotational speed from a map stored in memory and calculates a valve opening time of the fuel injection valve based on this basic injection time. The above-mentioned map is provided for when EGR is activated and when it is not activated, and the map for when EGR is activated is set more precisely than the map for when EGR is not activated. In addition, in the second invention, as shown in FIG. 9, an intake pressure detection means for detecting the intake pressure of an internal combustion engine having EGR, a rotation speed detection means for detecting the rotation speed of the engine, and a rotation speed detection means for detecting the rotation speed of the engine. The basic injection time is determined according to the fuel injection valve that supplies fuel and the above-mentioned intake pressure and rotational speed from a map stored in advance, and the opening time of the fuel injection valve is calculated based on this basic injection time. An electronically controlled fuel injection device comprising a valve opening time calculation means, wherein the map is set according to when EGR is not operating, and the map for when EGR is not operating is set corresponding to when EGR is operating. A correction map for correcting this is provided, and this correction map is set more finely than the EGR non-operation map.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a schematic configuration diagram of an internal combustion engine and its control system to which an embodiment of the present invention is applied.

1 is a cylinder of a six-cylinder internal combustion engine, and 2 is an intake pressure sensor that detects the intake air pressure in an intake manifold 3 connected to the cylinder 1, and is constituted by a semiconductor pressure sensor. 4 is an electromagnetically actuated fuel injection valve provided near each cylinder intake boat of the intake manifold 3, and 6 is a distributor. The rotor of the distributor 6 is driven to rotate at 1/2 of the engine rotation speed, and a rotation sensor 7 that outputs a signal indicating the engine rotation speed, fuel injection timing, and a cylinder discrimination signal is disposed inside.

9 is a throttle valve; 10 is a throttle position sensor that detects the opening degree of the throttle valve 9; 11 is a thermistor type water temperature sensor that detects the engine cooling water temperature;
2 is an intake air temperature sensor that detects intake air temperature. 13
is a vacuum servo type exhaust gas recirculation control valve (hereinafter abbreviated as EGR pulp) installed in the exhaust gas circulation path 17 connected between the intake manifold 3 and the exhaust manifold 16, and controls the EGR valve 13. A control line 18 is connected between the diaphragm chamber of the ECR valve 13 and the surge tank 19, and a solenoid valve 15 for switching whether or not to perform exhaust gas recirculation is installed in this control line 18. The solenoid valve 15 is connected to the output port 1-107 (Fig. 2) of the electronic control circuit 8, and for example, the EGR valve 1
On the other hand, when performing exhaust gas recirculation, it receives an activation signal to apply negative pressure near the throttle valve 9 in the surge tank 19 to the diaphragm chamber of the EGR valve 13.

FIG. 4 shows a block diagram of an electronic control circuit 8 that controls the fuel injection amount of the internal combustion engine to control the air-fuel ratio, various sensors, etc. The electronic control circuit 8 is mainly composed of a microcomputer.

The control circuit 8 takes in each detection signal from the intake pressure sensor 2, rotation sensor 7, throttle position sensor 10, water temperature sensor 11, and intake temperature sensor 12, calculates the fuel injection amount based on these detection data, and calculates the fuel injection amount. Air-fuel ratio control is performed by controlling the opening time of the injection valve 4. 100 is an MPU (microprocessor unit) that executes arithmetic processing according to a predetermined program, 101 is an interrupt control unit that outputs an interrupt signal to the MPU 100, and 102 is a unit that counts the rotation angle signal from the rotation sensor 7 and calculates the engine rotation speed. The counter section 104 for calculation is an A/D conversion section that selectively manually converts detection signals (analog signals) from the intake pressure sensor 2, throttle position sensor 10, water temperature sensor 11, and intake temperature sensor 12 into digital signals. It is. 1
05 is a ROM, which is a read-only memory in which map data, etc. used for programs and calculations are stored in advance; 106;
RAM is a non-volatile memory that can be written and read.
The memory contents are retained even after the key switch is turned off.

107 is an output boat connected to the electromagnetic valve 15, and 108 is an output counter unit including a register for outputting a fuel injection amount (time) control signal. Based on this, a duty ratio of a control pulse signal that controls the opening time of the fuel injection valve 4 is determined, and an injection amount control signal is output. Note that the control signal output from the output counter section 108 is applied to the fuel injection valve 4 of each cylinder via the power amplifier 110. Further, in the control circuit 8, the IPUloo, interrupt control section 101, input counter section 102, A/D converter 104, ROM 105, RAM 106, and output counter section 108 are each connected to the common hash 111, so that necessary data transfer is possible. This is performed according to a command from the MPU 100.

Next, the operation of the above configuration will be explained based on the flowchart of FIG.

The flowchart shown in FIG. 3 is a flowchart of a program that determines and executes whether EGR is activated or not, and also controls the fuel injection amount depending on when EGR is activated or deactivated. It is activated in response to a given interrupt signal synchronized with rotation, for example.

When an interrupt signal is given to the MPU 100 and this routine is started, first in step 201, the intake pressure P, cooling water temperature THW, and intake air temperature THA stored in the RAM 106 via the A/D converter 104 are stored as the latest data. and,
The rotation speed N calculated and stored in the RAM 106 is loaded into the counter section 102. Steps 202, 203
Then, it is determined whether the EGR operating conditions are satisfied. In other words, in step 202, the cooling water temperature T
It is determined whether the HW is higher than the comparative water temperature To (for example, 70'C) stored in advance in the ROM 105, and in step 203, the rotation 1i3N is set to RO in advance.
It is determined whether the rotation speed is lower than the comparison rotation speed No. (for example, 3000 rpm) stored in M105.

Then, in steps 202 and 203, both [YESJ,
In other words, if THW>To and N<No, it is assumed that the ECR operating conditions are satisfied, and the process proceeds to step 204, where the solenoid valve 15 is turned ON.
A command is given to the output port 107 to In response to this command, the output port 107 applies an actuation signal to the solenoid valve 15 to turn the solenoid valve 15 ONL and EGR pulp 1.
By transmitting negative pressure to the diaphragm chamber 3, the EGR pulp 13
Open the valve. Then, by opening the EGR valve 13, the exhaust gas is recirculated to the intake manifold 3.

Conversely, step 202. Alternatively, if it is determined "NO" in either step 203, it is assumed that the EGR operating conditions are not satisfied, and the process proceeds to step 206.
give commands to

In response to this command, the output port 107 does not provide an activation signal to the solenoid valve 15, turns off the solenoid valve, transmits atmospheric pressure to the diaphragm chamber of the EGR valve 13, and closes the EGR valve 13. Since the EGR valve 13 is closed, the exhaust gas is not recirculated to the intake manifold 3.

In this manner, ON/OFF control of the solenoid valve 15 is executed in step 204 or 206.

, After outputting the command to turn on the solenoid valve 15 in step 204, the process proceeds to step 205, and in step 205, as shown in FIG. Based on the stored two-dimensional EGR/ON map, the basic injection time T is determined according to the above-mentioned intake pressure P and rotational speed N.

Further, after outputting the command to turn off the solenoid valve 5 in step 206, the process proceeds to step 207, and step 20
6, the above intake pressure P is determined from the two-dimensional EGR-OFF map stored in the ROM 105, which is pre-memorized and set according to when EGR is not operating, as shown in FIG.
The basic injection time T is determined according to the rotation speed N and the rotation speed N.

Note that this basic injection time is set in each square (lattice point) in Figure 4 (al, (bl), and if the intake pressure P and rotation speed N are intermediate values between each setting. The basic injection time T is determined by interpolating the values on both sides.

By the way, the EGR ON map of Figure 6 (al) is shown in the same figure (
It is set more precisely on the intake pressure P side than the BL EGR/OFF map.

When the basic injection time T is determined in steps 205 and 207, the cooling water temperature THW and the intake air temperature T are determined in step 208.
7 for each correction value according to HA.

K THA is searched from the map stored in the ROM 105 and added to obtain 0 for the current total correction value. In step 209, the basic injection time T,
The current actual injection time, that is, the valve opening time T of the fuel injection valve 4 is calculated by multiplying and correcting and adding the invalid injection time Tv (determined by the battery voltage). Step 2
In step 10, the valve opening time T obtained in step 209 is output to the output counter section 108, and this routine is ended.

The output counter section 108 gives an injection amount control signal having a duty ratio according to the valve opening time T to the power amplifier 110 in response to a signal indicating the fuel injection timing from the interrupt control section 101, and opens the fuel injection valve 4. It is driven to inject and supply fuel to the engine.

By the way, as shown in Figure 5, the amount of fuel required by the engine for the intake pressure P when the rotation speed is constant is different when EGR is OFF (solid line) and when it is ON (broken line), and it can also be explained from the figure. As shown above, the change in the required fuel amount with respect to the intake pressure P of EGR 0FFBS is almost uniform, whereas
The same change when EGR is turned on is not uniform. Therefore, the EGR O
Rotation speed N and intake pressure P when FF and when EGR is ON
If the interval between the grid points of the map between rotational speed N and intake pressure P is set to be large, the required fuel amount when EGR is turned on (broken line) and the map are calculated as shown in Fig. 6. There is a large difference between the fuel amount (single chain &?), and conversely, the lattice points of the rotation speed N and intake pressure P of both maps are adjusted to the extent that the characteristics when EGR is turned on are satisfied. If the intervals are set finely, the amount of fuel required by the engine and the calculated amount of fuel can be almost matched regardless of whether EGR is ON or OFF, but the memory capacity required to store this map is enormous. Become something.

However, in this embodiment, the grid points of the map when EGR is ON are set finer than the grid points of the map when EGR is OFF. By configuring it in this way, the storage capacity does not become so huge (as shown in Fig. 7, the required fuel amount and the fuel amount calculated from the map are stored when EGR is ON and when EGR is OFF). Therefore, the controllability of the air-fuel ratio is improved.

By the way, in the above embodiment, a two-dimensional map is provided in which the basic injection time T is set according to the rotational speed N and the intake pressure P in correspondence to the EGROON and OFF times, respectively. The basic injection time T is set according to the rotation speed N and intake pressure P when EGR is OFF, and the BGR is set according to the rotation speed N and intake pressure P when EGR is ON.
If the configuration is equipped with a correction map knob that corrects the basic injection time Tp when the EGR is OFF, the number of lattice points of this correction map is larger than that when the EGR is OFF, and the EGR O
If the map is set more finely than the FF map, the same effect as in the above embodiment can be obtained.

Further, in the above embodiment, the map when EGR is ON is set more finely on the side of intake pressure P than the map when EGR is OFF, but it is also possible to set finely on the side of -revolutions N.

Furthermore, in each of the above embodiments, the basic injection time T is stored in a two-dimensional map set by the rotational speed N and the intake pressure P, but the one-dimensional map of the rotational speed N and the intake pressure P
The basic injection time T2 may be calculated by a combination of one-dimensional maps of If the settings are made more finely than when OFF, the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the first invention, a recirculation pipe that recirculates exhaust gas from an internal combustion engine to an intake pipe, an opening/closing means for opening and closing this recirculation pipe, and a control means for controlling opening and closing of this opening/closing means, An intake pressure detection means for detecting the intake pressure downstream of a throttle valve in an intake pipe of an internal combustion engine, a rotation speed detection means for detecting the rotation speed of the internal combustion engine, and an electromagnetic actuator for injecting and supplying fuel to the internal combustion engine. Determine the fuel injection valve to be used and the basic injection time, which is stored and set in advance by the map, using the above-mentioned intake pressure and the above-mentioned rotational speed, and calculate the valve opening time of the above-mentioned fuel injection valve based on this basic injection time. An electronically controlled fuel injection device comprising a valve opening time calculating means for calculating the valve opening time, wherein the map is determined depending on whether the opening/closing means is controlled to be open or closed by the control means. In addition, the second invention provides an electronically controlled fuel injection device characterized in that the map for the open control time is set more precisely than the map for the closed control time. For example, a recirculation pipe that recirculates exhaust gas from an internal combustion engine to an intake pipe, an opening/closing means for opening and closing this recirculation pipe, a control means for controlling opening/closing of this opening/closing means, and a downstream region of a throttle valve in an intake pipe of an internal combustion engine. An intake pressure detection means for detecting the intake pressure, a rotation speed detection means for detecting the rotation speed of the internal combustion engine, an electromagnetically actuated fuel injection valve for injecting and supplying fuel to the internal combustion engine, and a fuel injection valve stored in advance in a map. Electronic control comprising: a valve opening time calculation means that determines a set basic injection time using the intake pressure and the rotational speed, and calculates the valve opening time of the fuel injection valve based on the basic injection time. In the fuel injection device, the map is set according to when the opening/closing means is controlled to be closed by the control means, and the map for the closing control time is set according to when the opening/closing means is controlled to be open. Since the electronically controlled fuel injection system is equipped with a correction map that corrects the EGRO opening control, and this correction map is set more finely than the above-mentioned map for the closing control time, This has the excellent effect of making it possible to fully match the amount of fuel supplied to the engine with the amount of fuel required by the engine, improving the controllability of the engine's air-fuel ratio, and making it possible to obtain an appropriate air-fuel ratio. Moreover, since the capacity of the storage device only needs to be increased by the increment of the contents of the map for EGR opening control or the contents of the correction map, the capacity of the storage device does not become enormous.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the configuration of an internal combustion engine and its peripheral devices equipped with an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of the control circuit shown in FIG. 1, and FIG. Flowchart showing the operation of the example, FIG. 4 (al and (b)
l is the rotational speed N- at which the basic injection time Tp is set during EGROON and OFF, which is stored in the ROM.
A two-dimensional map of the intake pressure P, Figure 5 is a graph showing the fuel amount required by the engine with respect to the intake pressure P when the rotation speed is constant, Figure 6
The figure is a graph showing the required fuel amount of the engine and the fuel amount calculated from the map with respect to the intake pressure P when the rotation speed is constant according to the conventional configuration, and FIG. Graphs showing the fuel amount required by the engine and the fuel amount calculated by the map with respect to the atmospheric pressure P, FIGS. 8 and 9
The figure is a schematic configuration diagram schematically showing the configurations of the first invention and the second invention. 2... Intake pressure sensor, 4... Fuel injection valve, 7...
Rotation sensor, 8... Control circuit, 100... MPU,
105...ROM, 106...RAM.

Claims (2)

[Claims] (1) A recirculation pipe that recirculates exhaust gas from an internal combustion engine to an intake pipe, an opening/closing means for opening and closing this recirculation pipe, a control means for controlling opening and closing of this opening/closing means, and a downstream region of a throttle valve in an intake pipe of an internal combustion engine. An intake pressure detection means for detecting the intake pressure; a rotation speed detection means for detecting the rotation speed of the internal combustion engine; an electromagnetically actuated fuel injection valve for injecting and supplying fuel to the internal combustion engine; Electronic control comprising: a valve opening time calculation means that determines a set basic injection time using the intake pressure and the rotational speed, and calculates the valve opening time of the fuel injection valve based on the basic injection time. The above-mentioned map is provided depending on when the opening/closing means is controlled to open and when it is controlled to close by the control means, and the map is provided for when the opening/closing means is controlled to be closed by the control means. This electronically controlled fuel injection system is characterized by its map being more detailed than the map for closed control. (2) A recirculation pipe that recirculates the exhaust gas of the internal combustion engine to the intake pipe, an opening/closing means for opening and closing this recirculation pipe, a control means for controlling the opening and closing of this opening/closing means, and a downstream region of the throttle valve of the intake pipe of the internal combustion engine. an intake pressure detection means for detecting the intake pressure of the internal combustion engine; a rotation speed detection means for detecting the rotation speed of the internal combustion engine; and an electromagnetically actuated fuel injection valve for injecting and supplying fuel to the internal combustion engine; an electronic valve-opening time calculation means for determining a stored basic injection time using the intake pressure and the rotational speed, and calculating the opening time of the fuel injection valve based on the basic injection time; In the controlled fuel injection device, the map is set according to when the opening/closing means is controlled to be closed by the control means, and the map for when the opening/closing means is controlled to be closed is controlled to be open. 1. An electronically controlled fuel injection system, characterized in that a correction map is provided for making corrections to correspond to the time, and the correction map is set more finely than the map for the closed control.