JPS6296747A - Fuel injection timing controller - Google Patents

Abstract

PURPOSE:To improve the responsiveness of fuel feed at the time of transition so sharply, by making injection timing at the time of transition delay it more than that at the time of a steady state, and also making the setting timing of a fuel injection quantity to each injection at time of the said transition delay it more than that at time of the steady state. CONSTITUTION:In case of a device which separately controls each injection 2 attached to each branch suction passage 3b branched off form a surge tank 3a of a suction passage 3 according to an engine driving stage by a control unit 4, a judgement of the driving state is carried out at the initial stage of a compression stroke in each cylinder 1, and when stationary driving is judged, a fuel injection quantity is set immediately after the judgement. Then, fuel injection is made to be done at the initial stage of an explosion stroke. On the other hand, at the time of transition, for example, at the time of an acceleration driving judgement, the fuel injection quantity set timing is delayed, setting it down to the initial stage of an exhaust stroke, while the fuel injection timing also is delayed, setting it down to the initial stage of a suction stroke. With this constitution, sticking quantities to a fuel adsorption passage are lessened, whereby fuel feed is performable without entailing any response delay.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an engine fuel injection timing control device.

(Prior art) Conventionally, in order to precisely control the amount of fuel injected to each cylinder of an engine, an injector was provided in the intake path of each cylinder on the downstream side of the intake manifold, and fuel was injected at appropriate timing. For example, Japanese Patent Laid-Open No. 57-108428 describes a fuel injection supply for an engine in which fuel is injected into the intake passage at the end of each cylinder's intake stroke to promote fuel vaporization. The equipment is described.

(Problems to be Solved by the Invention) As described above, as long as fuel is injected into the intake passage, if fuel is injected at an early point, such as at the end of the intake stroke, a considerable portion of the injected fuel will be injected into the intake passage. A phenomenon occurs in which it adheres to the wall surface and is sucked into the cylinder with a time delay.

However, during steady operation, no particular problem arises because the fuel adhering to the wall is sucked in in fixed amounts with a certain delay, but during transient operating conditions such as during acceleration, the fuel supply response is proportional to the amount of fuel adhering to the wall. There will be a delay.

In particular, with conventional equipment, even during steady operation,
Even during transient operating conditions, the fuel injection amount was determined at a predetermined time prior to fuel injection, so there was a time lag between the determination of the fuel injection amount and the fuel injection, and during that time, the amount of intake air, engine speed, etc. fluctuated. Under such transient operating conditions, it is not possible to accurately respond to changes in fuel demand.

As a result, there is a problem that acceleration performance and deceleration performance deteriorate. In other words, there may be a shortage or excess of the required fuel.

Furthermore, when acceleration is detected to correct this, if an acceleration increase is performed based on a preset increase value, this is prospective control and therefore does not have the accuracy of an appropriate increase value.

(Means for Solving the Problems) A fuel injection timing control device according to the present invention is a fuel injection timing control device for an engine that injects fuel at a predetermined injection timing for each cylinder. In addition to providing an injection timing changing means that delays the injection timing during a steady state, an injection amount determining timing changing means is provided that delays the determining timing of the fuel injection amount for each injection during a transient period from the determining timing of the fuel injection amount during a steady state. It is something.

(Function) In the fuel injection timing control device according to the present invention, the fuel injection amount is calculated at a predetermined timing in a steady operating state based on the engine speed, intake air amount, etc. detected by the operating state detection means. Fuel is injected and supplied to each cylinder at a predetermined timing, but during transient operating conditions where the intake air amount etc. fluctuate, the injection amount determination timing changing means is used to inject and supply fuel at a predetermined timing later than in normal conditions. The fuel injection amount determination timing is changed so that the fuel injection amount is determined based on data (intake air amount, engine speed, etc.), and the injection timing change means injects at a predetermined timing that is later than during normal operation. The injection timing will be changed accordingly.

In other words, during a transient operating state, fuel is injected at a relatively late time when it is possible to inhale in the intake stroke, and the fuel injection amount is determined based on the latest data at a relatively late time that is in time for the above-mentioned injection time.

(Effects of the Invention) According to the fuel injection timing control device according to the present invention, as explained above, the fuel injection timing control device according to the present invention performs control during transient periods (during acceleration and deceleration) based on the latest data (intake air amount, engine speed, etc.). Since the fuel injection amount can be determined, it is possible to control the fuel injection amount with precision, and the fuel injection timing can be delayed as much as possible, which greatly improves the responsiveness of fuel supply during transient times. .

(Example) Embodiments of the present invention will be described below with reference to the drawings.

The fuel injection timing control device according to this embodiment is a case where the present invention is applied to a vertical four-cylinder engine E.

As shown in FIG. 1, injectors 2 for injecting fuel into each cylinder 1 of an engine E at a predetermined timing are installed in each branch intake passage 3b branching from a surge tank 3a of an intake passage 3. is connected to the fuel supply system, and is provided with a control unit 4 that outputs drive signals to these four injectors 2.The control unit 4 is connected to the following various sensors that detect the operating state of the engine. A detection signal is output.

That is, an air flow meter 6 is installed in the intake passage 3 downstream of the air cleaner 5, a water temperature sensor 7 is installed in the cylinder block of the engine E to detect the temperature of the cooling water in the water jacket, and a A crank angle sensor 8 is provided in conjunction with the crankshaft to detect the crank angle, the distributor is provided with a cylinder identification sensor 9 that detects the intake top dead center of the first cylinder, and the exhaust pipe 10 is provided with a cylinder identification sensor 9 that detects the intake top dead center of the first cylinder. 0□sensor 1 detects the oxygen concentration of
1 is installed.

The control unit 4 converts detection signals from the air flow meter 6, water temperature sensor 7, and 0□ sensor 11 into an A/D converter.
An A/D converter for conversion, an input circuit that receives detection signals from the crank angle sensor 8 and cylinder identification sensor 9, shapes the waveforms, and outputs signal numbers for the intake TDC and intake ATDC of the first cylinder, an input/output interface, and a CPU ( central processing unit)
, ROM (read-only memory) in which various calculation and control programs described below are input and stored in advance, RA
It is comprised of a random access memory (M), a free running counter, a drive circuit that outputs a drive signal to each injector 2, and the like.

The control unit 4 determines the timing of each stroke of intake, compression, explosion, and exhaust for each cylinder 1 based on the detection signals from the crank angle sensor 8 and the cylinder identification sensor 9, and sends the information to the injector 2 of each cylinder 1. The basic fuel injection amount is determined from the fuel injection amount map and calculation formula that are input in advance to the ROM based on the intake air amount and engine speed (this is given by the detection signal from the crank angle sensor 8). The fuel injection amount to each cylinder 1 is set by applying a correction calculation to this basic fuel injection amount based on the cooling water temperature and the 00□ concentration in the exhaust gas.

FIG. 2 shows, for the first cylinder 1, (1) determination timing for determining whether it is in a steady state of operation or a transient state of operation (during acceleration or deceleration), (2) timing of determining fuel injection amount in steady state, (3) Fuel injection timing during steady state, (4) fuel injection amount determination timing during acceleration,
It is a time chart illustrating (5) fuel injection timing during acceleration, (6) intake air amount, etc. in relation to the stroke.

The above (1) is common to all cylinders 1, and (2) to (
5) corresponds to each cylinder 1 (the first cylinder in FIG. 2).

As shown in the figure, the operating condition is determined at the beginning of the compression stroke, and in steady state, the fuel injection amount is determined immediately after the above determination, and the time from injection to intake is made as long as possible to minimize the vaporization of the injected fuel. In order to accelerate the acceleration, fuel is injected from the end of the compression stroke to the beginning of the explosion stroke (in the case shown, the beginning of the explosion stroke), and the fuel vaporized in the intake port between the compression stroke and the exhaust stroke flows into cylinder 1 during the intake stroke. It will be inhaled inside.

On the other hand, when it is determined that the driving state is accelerating, the fuel injection amount is determined based on the latest data such as the intake air amount, so the fuel injection amount determination timing is changed later and the exhaust stroke is delayed. The fuel injection amount is determined from the beginning to the end yu1 (in the illustrated case, the beginning of the exhaust stroke), and the fuel injection timing is also changed to be later, so that fuel is injected at the beginning of the intake stroke (at the top of the intake stroke).

In other words, by determining the fuel injection amount using the latest data as late as possible in time for fuel injection at the intake top, it is possible to determine the fuel injection amount that corresponds to operation 1 of engine E as much as possible, and at the intake top. By injecting the fuel, the amount of the injected fuel adhering to the wall surface of the intake passage can be minimized and the fuel can be supplied without response delay.

In addition, the fuel injection timing during steady state varies depending on the operating condition.
It may be determined based on a map or arithmetic expression that is inputted and stored in the OM in advance.

Although FIG. 2 does not show the time of deceleration, since the fuel injection amount is determined based on the latest data, the fuel injection amount determination timing and the fuel injection timing are set later as in the case of acceleration.

The above is an explanation about the first cylinder 1, but the second cylinder 1
- Regarding the fourth cylinder 1, the fuel injection amount determination timing and fuel injection timing are controlled in the same manner as described above.

FIG. 3 shows a schematic flowchart of a control routine regarding fuel injection amount determination timing, fuel injection timing, etc. performed by the control unit 4.
indicates each step.

After initialization in Sl, predetermined data is read in S2, and in S3 it is determined whether or not it is the judgment time to judge the operating state. It is determined whether the state is the same or not.

As a result of the determination in S4, if the process is in a transient state (acceleration or deceleration), the process moves to S9, and if it is not a transient state, the process moves to S5.

In S5, it is determined whether or not it is time to determine the fuel injection amount in a steady state. If it is not the determination time, the process returns to S5 again. When the determination time comes, the process moves to 36, and in S6, the latest data (
Engine speed, intake air amount, cooling water temperature and Oz? M degree, etc.) is read, and the fuel injection amount is calculated in S7.
In S8, it is determined whether or not the compression top is reached, and if it is not the compression top, the process returns to S8 again and when the compression top is reached, the S
13, where fuel injection is performed.

When it is determined in S4 that the state is in a transient state, S9
In S9, it is determined whether or not it is time to determine the fuel injection amount during a transient period. If the determination time has not yet come, the process returns to S9 again, and when the determination time has come, the process shifts to SIO and the latest data (engine speed, intake Air volume, cooling water temperature and 0□
concentration, etc.) is read, the fuel injection amount is calculated in Sll, it is determined in S12 whether or not the intake is at the top, and if it is not the intake top, the process returns to S12 again, and when the intake is at the top, the process moves to 313 and fuel injection is executed. . S13
From there, the process moves to S2, and the same process as above is repeated.

Incidentally, after an appropriate step such as 82, S3 or 84 of the above control routine, the interrupt processing shown in FIG. 4 is executed,
While determining the basic fuel injection amount for each cylinder,
Instead of IO and Sll and S6 and S7, steps S20 and 321 in FIG. 5 may be executed, respectively.

That is, the basic fuel injection amount is determined in the above interrupt processing, the basic fuel injection amount is read in S20, and the basic fuel injection amount is read in S21.
In this system, the basic fuel injection amount is subjected to a correction calculation based on the cooling water temperature and the 02 concentration in the exhaust gas to determine the fuel injection amount.

Note that the basic fuel injection amount may be determined using a map or an arithmetic expression based on the opening degree of the throttle valve and the engine speed.

According to the fuel injection timing control device according to the above embodiment, by delaying the fuel injection amount determination timing during transitions such as acceleration and deceleration compared to steady times, the latest data (intake air amount, Since the fuel injection amount is determined based on the engine speed (engine speed, etc.) and fuel is injected at the latest timing, at the top of the intake air, the amount of fuel as close as possible to the required amount of fuel requested by the engine E is supplied without response delay. can. This makes it possible to improve acceleration performance and deceleration performance.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is an overall configuration diagram of a fuel injection amount control system for a 4-cylinder engine, and Fig.
FIG. 3 is a flowchart showing the fuel injection control routine, and FIG. 4 is a flowchart showing the interrupt processing routine according to a modified example. , and FIG. 5 is a flowchart showing some steps according to the modification example. 1. Cylinder, 2. Injector, 4. Control unit, 6. Air flow meter, 8. Crank angle sensor, 9. Cylinder identification sensor. Patent applicant: Mazda Motor Corporation Agent: Toshio Okamura Figures 4 and 5

Claims (1)

[Claims] (1) In a fuel injection timing control device for an engine that injects and supplies fuel to each cylinder at a predetermined injection timing, an injection timing changing means for retarding the injection timing during a transient period from the injection timing during a steady state; 1. A fuel injection timing control device comprising: injection amount determination timing changing means for delaying the determination timing of the fuel injection amount for injection from the determination timing of the fuel injection amount in a steady state.