JPS6278443A - Fuel supply amount controller of internal combustion engine with supercharger - Google Patents

Abstract

PURPOSE:To prevent emission from deteriorating by restricting fuel supply amount calculated according to the operating condition below the set value in order to constantly control fuel supply amount most appropriately when a speed reducing state is found out by a speed reducing state judging means. CONSTITUTION:The device stated in a diagram calculates fuel supply amount by a fuel supply amount calculating means M3 on the basis of a detected result of an operation condition detecting means M2 to for detecting the operating conditions of an internal combustion engine M1 including engine speed and intake amount, so as to control fuel supply amount by a fuel supply amount controlling means M4 according to said calculated value. In this case, when a speed reducing state is found out by a speed reducing state judging means M5, the upper limit of fuel supply amount calculated by the calculating means M3 is set by an upper limit setting means M6. And, fuel supply amount is made to be restricted by a restricting means M7 according to the upper limit set by the means M6.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a fuel supply amount control device for an internal combustion engine with a supercharger, and more specifically, a fuel supply amount control device for a supercharged internal combustion engine, which calculates a fuel supply amount using engine rotational speed and intake air m as parameters, The present invention relates to a fuel supply amount control device for a supercharged internal combustion engine that controls the supply amount.

[Prior Art] Conventionally, as a fuel supply amount control device for an internal combustion engine,
An electronically controlled fuel supply system that detects the operating conditions of the internal combustion engine, such as intake air volume, engine speed, intake air temperature, and cooling water temperature, and controls the internal combustion engine's fuel supply amount according to the detected operating conditions. There is a control device.

The fuel supply amount control device uses, for example, a computer to calculate the opening time of the injection valve (basic injection time) from the intake air amount to the internal combustion engine and the internal combustion engine rotation speed, and calculates the valve opening time (basic injection time) of the injector using a computer, The actual injection time is determined by adding corrections based on signals from each sensor.

The injector is then driven based on the determined injection signal.

With the development of electronic technology in recent years, various types of control have been devised and put into practical use for the above-mentioned electronically controlled fuel supply ff1RJIJ control device.
As described in the publication, by setting the upper limit or lower limit of the fuel injection time and controlling the fuel injection time so that it does not exceed this upper limit or lower limit, deterioration of emissions and drivability can be prevented. There are suggestions for improvement.

[Problems to be Solved by the Invention] However, in the conventional example described above, the supercharged internal combustion engine is not necessarily perfect, and the following problems arise.

In a supercharged internal combustion engine, when the throttle pedal is returned to the closed position and deceleration occurs, the compressor rotates at high speed due to inertia, and the pressure P1 before passing through the compressor is higher than the pressure P2 before passing through the compressor. It also becomes more expensive. That is, P
This results in a state where 1/P2 is large and the intake air amount Q is small.

Since the amount of intake air in this state surges periodically, the basic injection time determined by equation (1) fluctuates greatly, resulting in problems such as deterioration of emissions and impairing drivability.

Let us now explain the surging of the intake air amount in more detail. The conditions that cause surging are the intake air mQ and compressor pressure ratio Pi /P2 as shown in the graph of Figure 7.
The pressure difference between the pressure P1 of the intake air downstream of the compressor and the pressure P2 of the intake air upstream of the compressor causes a backflow from upstream to downstream of the compressor, and then the pressures P1 and P2 When they become equal, the turbine supercharges the air again and generates a positive flow. Moreover, when the pressure of P1 becomes higher than P2 after that, a backflow occurs. That is, by repeating the above process, the air flow sensor output periodically surges and fluctuates in increase and decrease. As a result, the injection time varies greatly as described above.

Therefore, an object of the present invention is to solve the above-mentioned problems, and even when the thrower valves 1 to 1 are closed and the deceleration is in progress, the amount of fuel supplied is optimally controlled, the deterioration of emissions is prevented, and the drivability is improved. It is an object of the present invention to provide a fuel supply amount control device for a supercharged internal combustion engine that does not cause any damage.

[Means for Solving the Problems] As a means for solving the above problems, the present invention adopts a configuration as illustrated in the basic configuration diagram of FIG. 1. That is, the present invention includes: an operating state detecting means M2 that detects the operating state of the internal combustion engine including the rotational speed and intake air amount of the internal combustion engine M1; and based on the detection result of the operating state detecting means M2, Fuel 1 supply amount calculation means M3 for calculating the fuel supply amount of Fuel 1, and Fuel supply amount control means M4 that controls the Fuel 1 supply source to the internal combustion engine according to the calculated Fuel 1 supply amount. A fuel supply amount control device for a supercharged internal combustion engine, further comprising: a deceleration state determining means M5 for determining a deceleration state of the internal combustion engine M1; - a deceleration state is determined by the deceleration state determining means M5; upper limit setting means M6 for setting the upper limit of the fuel supply amount calculated by the fuel supply amount calculation means M3; and limiting the fuel supply amount by the upper limit set by the upper limit setting means M6. The gist of the present invention is a fuel supply m control means for a supercharged internal combustion engine, which is characterized by comprising: a limiting means M7 for controlling fuel supply m of a supercharged internal combustion engine;

Here, the internal combustion engine M1 is an internal combustion engine with a supercharger.

The operating state detection means M2 detects a physical quantity that determines the amount of fuel supplied to the internal combustion engine M1, and needs to detect at least the amount of intake air and the engine rotation speed. Furthermore,
For example, it may be configured to detect intake air temperature, cooling water temperature, etc. Various types of detection means can be considered, such as an air flow meter, a rotational speed sensor, an intake temperature sensor, and a water temperature sensor.

The fuel supply amount calculation means M3 is the above-mentioned operating state detection means M.
The basic injection time is determined using the intake air amount detected in step 2 and the rotational speed of the internal combustion engine as parameters, and the fuel supply amount to be controlled by the fuel supply m control means M4 is calculated. The fuel supply amount may be calculated by correcting the basic injection time according to the parameters.

The fuel supply amount control means M4 controls the fuel supply amount by, for example, opening and closing an electromagnetic fuel injection valve according to the fuel supply amount calculated by the fuel supply amount calculation means M3.

The deceleration state determination means M5 is for determining the deceleration state of the internal combustion engine M1, and detects the opening degree of the throttle valve using, for example, a potentiometer, and detects when the opening degree is below a predetermined value. It may be determined that the vehicle is in a deceleration state, or alternatively, the intake pipe pressure may be detected and it may be determined that the vehicle is in a deceleration state when the intake pipe pressure is less than or equal to a predetermined value. The predetermined value for the above determination may be, for example, a predetermined constant value, or may be variable using the rotational speed of the internal combustion engine or the like as a parameter.

The upper limit setting means M6 sets the upper limit of the fuel supply amount when the deceleration state determination means M5 determines that the vehicle is in a deceleration state. Note that the upper limit value may be a predetermined constant value, or may be variable using a parameter such as the rotational speed of the internal combustion engine.

The limiting means M7 limits the fuel supply amount controlled by the fuel supply amount control means M4 by the upper limit set by the upper limit setting means M6, for example, the amount of fuel supplied calculated above and the amount set above. When the calculated fuel supply amount exceeds the upper limit value by comparing with the upper limit value, the fuel supply amount is suppressed to the upper limit value.

[Operation] In the fuel supply amount control device for a supercharged internal combustion engine of the present invention configured as described above, the fuel supply amount is calculated based on the detection result of the operating state, and the fuel supply amount is determined based on the calculation result. The amount of supply is controlled. Then, when the deceleration state determination means M5 determines that the deceleration state is present, the upper limit setting means M6 sets the upper limit value of the fuel supply amount, and the fuel supply amount calculated by the fuel supply amount calculation means M3 is set to the upper limit value. The fuel supply amount is limited by the limiting means M7 so as not to exceed the amount. Then, according to this fuel supply amount, the fuel supply amount control means M4
By controlling the fuel supply amount, unnecessary fuel supply amount caused by compressor surge is eliminated and a stable fuel supply amount is achieved.

[Embodiment] The configuration of an embodiment of the present invention will be described below with reference to FIGS. 2 to 6.

FIG. 2 is a schematic diagram of a supercharged internal combustion engine to which this embodiment is applied.

In the figure, 1 is the main body of the internal combustion engine, 2 is a turbocharger that uses the flow velocity of exhaust gas to turn a turbine 4 installed in the exhaust flow path 3, and supercharges the intake air by a compressor 6 installed in the intake flow path 5. The main body of the feeder, 7 is an intercooler for cooling intake air, 8 is a well-known wastegate valve provided in the bypass passage 3a of the exhaust flow path 3 that bypasses the turbine 4 and adjusts the boost pressure, 9 is the internal combustion engine 1 10 is an oxygen sensor that detects the oxygen concentration in exhaust gas; 11 is an igniter that generates high voltage; 12
13 is a fuel injection valve that injects fuel, 13 is a distributor that distributes high voltage from the igniter 11 to each cylinder of the internal combustion engine 1 in synchronization with the crank angle, and 14 is a distributor for each cylinder 1.
Each figure represents an ignition plug that is screwed onto the top of 5 and generates an electric spark to ignite the air-fuel mixture. Also, 16
is attached to the distributor 13, and the rotor 17
18 is a cylinder discrimination sensor that outputs one pulse for every two rotations of the internal combustion engine 1; 19 is a throttle valve 21;
22 is an air flow meter that detects the flow rate Q of intake air.

Next, 30 receives detection signals from the above-mentioned sensors, and determines the amount of fuel injected from the fuel injection valve 12 or the timing of high voltage generation of the igniter 11, that is, the ignition timing of the spark plug 14, depending on the operating state of the internal combustion engine. This is an electronic control circuit that calculates and controls the

FIG. 3 shows a block diagram of the electronic control circuit 30 and its related parts. As shown in the figure, the electronic control circuit 30 packs the output signals from each of the sensors.
Hekapo with D converter, multiplayer etc.-1~31
A central processing unit (CP) executes fuel injection amount control and ignition timing control based on detection signals from each sensor inputted through this input port 31.
U) 32 and a read-only memory (ROM > 33) that stores data such as control programs and maps necessary for the CPU 32 to execute fuel injection control, ignition timing control, etc. a random access memory (RAM) 34 that is read and written to; an igniter 11;
Output boat 35 that outputs a drive signal to the fuel injection valve 12 etc.
, a path line 36 that connects each of the above sections and serves as a data path, and a power supply circuit 37 that supplies power to each of the above sections.

Hereinafter, fuel injection control executed in the electronic control circuit 30 configured as described above will be explained in detail with reference to the flowchart shown in FIG. 4.

The flowchart in FIG. 4 represents a fuel injection control output routine that calculates the fuel injection amount fJJ according to the operating state of the internal combustion engine, and opens the fuel injection valve 12 according to the fuel injection amount determined by this process. An injection pulse will be output.

When the process starts, first, step 100 is executed, and the intake air amount Q,
The engine rotational speed NE, throttle opening θ, intake temperature T1, and cooling water temperature T2 are read, and the process moves to step 11.0.

In step 110, the basic injection time TD is calculated using the intake air amount Q and engine rotational speed NE read in step 100 above. That is, the basic injection time Tp has the following relationship and can be calculated as follows.

In the following step 120, it is determined whether the opening degree θ of the throttles 1 to 3 read in the step 100 is smaller than a predetermined value 0thd, for example, 5%, and
(If I, the process moves to step 130.

In step 130, the injection time TI) is determined using a table as shown in FIG. 5, which uses the engine rotational speed NE as a parameter.
The upper limit value Tm@ is calculated.

Then, in the following step 140, the step controller 10
It is determined whether Tp calculated in step 130 is greater than Tm calculated in step 130, and if Tp>Tm, the process moves to step 150, and the value of the basic injection time Tp is set to the upper limit Tm.
, and the process moves to step 160.

On the other hand, if it is determined in step 120 that θ≧θthd, or if it is determined that Tp≦Tm in step 150, the process directly proceeds to step 160.

In step 160, the actual injection time Ti is calculated based on Tp determined in the steps up to the above. In other words, the actual injection time Ti is: Ti = C p 10 ■ ... (3) (
C: correction coefficient TV: invalid injection time (11r1 injection time), and the actual injection time Ti can be calculated by multiplying Tp by the correction coefficient C determined from the intake temperature T1 and cooling water temperature T2, and adding the invalid injection time TV. . This completes the processing of this routine.

Here, the process of step 120 is a process for determining the deceleration state of the internal combustion engine, and when it is determined that the blower I/small opening θ is smaller than 5%, for example, the internal combustion It is determined that the engine is in a deceleration state and step 13
Fuel injection from 0 to 150! ; FIITp control processing is performed. The process of step 140 is to judge whether the fuel injection time Tp exceeds the upper limit value Tm calculated in step 130, for example, during sudden deceleration. If it does, the fuel injection time Tp is changed in step 150. It is designed to be suppressed to the upper limit value Tm.

Figure 6 shows time 1 which shows the relationship between the throttle opening θ, the intake air @Q detected by the airflow meter, and the actual fuel injection time T1.As can be seen from the figure, the intake air ff1Q causes surging. Even if the actual fuel is jQJO
, 'I hardly changes.

In this embodiment, which is configured as J: above, even if the intake air ff1Q causes 4 nosing when the throttle valve is closed and deceleration occurs, the actual fuel injection time T1 is always constant. As a result, the amount of fuel supplied can be optimally controlled, preventing deterioration of emissions, and drivability will not be impaired.

In particular, in this embodiment, the upper limit value 1 m of the fuel injection time tJJ is changed using the engine rotational speed NE as a parameter, so that the fuel supply amount can be controlled more optimally.

In the above embodiment, the opening of the blower 1 to 1 valves was used to determine the VL and speed state of the internal combustion engine, but the amount of depression of the accelerator pedal to open the throttle valve (accelerator opening) and the intake pipe The deceleration state may be determined using pressure, a signal from an idle switch that detects the fully open state of the throttle valve, or the like. In addition, in the above embodiment, the internal combustion engine is equipped with a supercharger using an exhaust turbine that uses exhaust energy. Even if it uses a machine, the same effect will be obtained by 1q.

[Effects of the Invention] As detailed above, in the fuel supply amount control device for a supercharged internal combustion engine of the present invention, when the deceleration state determination means determines that the deceleration state is present, the fuel supply O is turned off. It is configured to suppress it to a predetermined value or less. Therefore, even if the amount of intake air increases during deceleration, combustion is always optimally controlled, deterioration of emissions is prevented, and drivability is not impaired.

[Brief explanation of drawings]

Fig. 1 is a block diagram that does not show the configuration of the present invention, Figs. 2 to 6 show an embodiment of the present invention, and Fig. 2 is a supercharged internal combustion engine of the present embodiment and its peripheral equipment. 3 is a block diagram showing the configuration of the electronic control circuit,
Figure 4 shows flowcharts 1 to 1 showing the fuel injection amount calculation routine, Figure 5 is a graph showing table A of the relationship between engine rotational speed NE and upper limit value Tm, and Figure 6 shows flowcharts 1 to 1 showing the routine for calculating fuel injection amount. FIG. 7 is a time chart showing the relationship between intake air ff1Q and actual fuel injection time 1-i, and FIG. 7 is a graph showing the compressor υ-range. M]...Internal combustion engine M2...Operating state detection means M3...Fuel supply amount calculation means M4...Fuel feed rate control means M5...Deceleration state determination means M6...Upper limit setting means M7...Restricting means 1...Internal combustion engine 2...Supercharger body 9...Water temperature sensor 16...Rotation angle sensor 18...Cylinder discrimination sensor 19...Intake temperature sensor 1 No 20... Throttle sensor 22... Air flow meter 30... Electronic control circuit

Claims (1)

[Scope of Claims] 1. Operating state detection means for detecting the operating state of the internal combustion engine, including the rotational speed and intake air amount of the internal combustion engine, and supplying fuel to the internal combustion engine based on the detection result of the operating state detection means. a fuel supply amount calculation means for calculating the fuel supply amount; and a fuel supply amount control means for controlling the fuel supply amount to the internal combustion engine according to the calculated fuel supply amount. The supply amount control device further includes a deceleration state determining means for determining a deceleration state of the internal combustion engine, and when the deceleration state determining means determines the deceleration state,
Upper limit setting means for setting an upper limit of the fuel supply amount calculated by the fuel supply amount calculation means; and limiting means for limiting the fuel supply amount by the upper limit set by the upper limit setting means. A fuel supply amount control device for an internal combustion engine with a supercharger, characterized by: 2. The deceleration state determining means determines that the internal combustion engine is in a deceleration state when the opening degree of the throttle valve of the internal combustion engine is less than or equal to a predetermined value. Device. 3. The fuel supply amount control device for a supercharged internal combustion engine according to claim 1, wherein the deceleration state determining means determines that the deceleration state is present when the intake pipe pressure is below a predetermined value. 4. The fuel supply amount for a supercharged internal combustion engine according to any one of claims 1 to 3, wherein the upper limit of the fuel supply amount set by the upper limit setting means varies depending on the rotational speed of the internal combustion engine. Control device.