JP6213379B2 - Engine fuel injection timing control device - Google Patents

Description

  The present invention relates to a fuel injection timing control device for an engine provided with a variable valve timing mechanism for changing the opening / closing timing of an intake valve.

  An engine fuel injection timing control device having a variable valve timing mechanism for changing the opening / closing timing of an intake valve is known as a prior art.

  In Patent Document 1, the phase change amount of the intake valve opening / closing timing is detected, and the fuel injection timing by the fuel injection valve is set using the detected phase change amount as a parameter. As a result, it is possible to prevent fuel injection from continuing until the latter half of the intake air, blow-off of the fuel, and the like, thereby contributing to improving the output performance of the internal combustion engine and reducing harmful components in the exhaust gas.

Japanese Patent Laid-Open No. 11-141387

  However, in Patent Document 1, if the fuel injection timing is set when the opening / closing timing of the intake valve is changed, the intake valve is set between the fuel injection timing setting and the start of fuel injection at the set fuel injection timing. The opening / closing timing is changed. Due to this change, there is a possibility that the fuel injection timing based on the opening / closing timing of the intake valve will not be an appropriate time and combustion stability cannot be ensured.

  The present invention has been made in view of the above point, and the problem is that the fuel injection start timing based on the intake valve opening / closing timing is set to an appropriate timing even when the intake valve opening / closing timing is transitional. There is.

  In order to solve the above problem, the present invention predicts the advance amount of the opening / closing timing of the intake valve at the set fuel injection start timing, and uses the fuel injection valve based on the predicted advance amount. The fuel injection start timing is reset.

  Specifically, the present invention is directed to a fuel injection timing control device for an engine having a variable valve timing mechanism for changing the opening / closing timing of the intake valve, and has taken the following solution.

That is, the first invention is a setting means for setting a fuel injection start timing by the fuel injection valve based on an actual advance angle amount of the opening / closing timing of the intake valve at a predetermined timing, and the fuel set by the setting means Predicting means for predicting the advance amount of the opening / closing timing of the intake valve at the injection start time, and the setting means is based on the advance angle amount predicted by the predicting means. The fuel injection by the fuel injection valve is performed during the compression stroke, and the prediction of the advance amount by the prediction means and the resetting of the fuel injection start time by the setting means are as follows: It is characterized in that it is performed when the AWS is operated to change the opening / closing timing of the intake valve in the advance direction and the ignition timing in the retard direction .

  According to this, the predicting means predicts the advance amount of the opening / closing timing of the intake valve at the fuel injection start timing set by the setting means. Then, the setting means resets the fuel injection start timing by the fuel injection valve based on the advance amount predicted by the prediction means. Therefore, even when the intake valve opening / closing timing changes, the fuel injection start timing based on the intake valve opening / closing timing can be set to an appropriate time.

Further, the advance amount is predicted by the predicting means and the fuel injection start timing is reset by the setting means when the AWS is operated to change the opening / closing timing of the intake valve in the advance direction and the ignition timing in the retard direction. For this reason, even at the time of the AWS operation in which the opening / closing timing of the intake valve is changed in the advance direction, the fuel injection start timing based on the opening / closing timing of the intake valve can be set to an appropriate time.

  According to a second aspect, in the first aspect, the prediction of the advance amount by the prediction unit and the resetting of the fuel injection start timing by the setting unit are repeated a plurality of times.

  According to this, the prediction of the advance amount by the predicting means and the resetting of the fuel injection start timing by the setting means are repeated a plurality of times, so that the intake valve opening / closing timing can be changed even when the intake valve opening / closing timing is changed. Based on this, it is possible to converge the fuel injection start timing to an appropriate timing.

  According to a third aspect of the present invention, in the first or second aspect of the invention, the prediction of the advance amount by the prediction unit and the resetting of the fuel injection start time by the setting unit are performed when the fuel injection start time is stable in combustion of the engine. It is performed until it meets the requirement standard of sex.

According to this, the prediction of the advance amount by the predicting means and the resetting of the fuel injection start timing by the setting means are performed until the fuel injection start timing satisfies the required standard for combustion stability of the engine. The engine combustion stability can be ensured even when the switching timing of the opening / closing timing is transitional .

  According to the present invention, the advance amount of the opening / closing timing of the intake valve at the set fuel injection start timing is predicted, and the fuel injection start timing by the fuel injection valve is re-established based on the predicted advance amount. Therefore, even when the intake valve opening / closing timing changes, the fuel injection start timing based on the intake valve opening / closing timing can be set to an appropriate time.

1 is a cross-sectional view showing a schematic configuration of an engine provided with a variable valve timing mechanism in a fuel injection timing control device according to an embodiment of the present invention. It is a block diagram which shows a fuel injection timing control apparatus. It is a figure which shows an injection start timing (SOI (Start Of Injection)) map. It is a figure for demonstrating reset control of the fuel-injection start time at the time of AWS action | operation. It is a flowchart which shows the reset control operation | movement of the fuel injection start time at the time of AWS action | operation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

  FIG. 1 shows an engine provided with a variable valve timing mechanism in a fuel injection timing control apparatus according to an embodiment of the present invention. The engine 2 is an in-line four-cylinder gasoline engine in which first to fourth cylinders are sequentially arranged in series in a direction perpendicular to the paper surface of FIG. 1, and is mounted on a vehicle such as an automobile. In the engine 2, a cam cap 3, a cylinder head 4, a cylinder block 5, a crankcase (not shown), and an oil pan (not shown) are connected vertically, and the inside of four cylinder bores 7 formed in the cylinder block 5 is inside. A piston 8 slidable and a crankshaft 9 rotatably supported by the crankcase are connected by a connecting rod 10, and a combustion chamber 11 is defined by the cylinder bore 7, piston 8 and cylinder head 4 of the cylinder block 5. It is formed for each cylinder.

  The cylinder head 4 is provided with an intake port 12 and an exhaust port 13 that open to the combustion chamber 11, and an intake valve 14 and an exhaust valve 15 that open and close the intake port 12 and the exhaust port 13, respectively. Equipped. The intake valve 14 and the exhaust valve 15 are urged in the closing direction (upward in FIG. 1) by return springs 16 and 17, respectively, and cam portions 18a and 19a provided on the outer periphery of the rotating cam shafts 18 and 19, respectively. Cam followers 20a and 21a, which are rotatably provided at substantially central portions of the swing arms 20 and 21, are pushed downward, and the swing is supported with the top of the pivot mechanism 22 provided on one end side of the swing arms 20 and 21 as a fulcrum. As the arms 20 and 21 swing, the intake valve 14 and the exhaust valve 15 are pushed downward at the other end of the swing arms 20 and 21 against the urging force of the return springs 16 and 17 so as to open. It is configured.

  The camshaft 18 has a motor-driven electric variable valve timing mechanism 23 (hereinafter referred to as VVT) on the intake side that changes the opening / closing timing of the intake valve 14 (changes the phase angle of the camshaft 18 with respect to the crankshaft 9). Provided (see FIG. 2). The camshaft 19 is provided with an exhaust-side variable valve timing mechanism (not shown) that changes the opening / closing timing of the exhaust valve 15. The engine 2 is provided with a fuel injection valve 24 for injecting fuel into the intake port 12 for each cylinder. The engine 2 is provided with a spark plug 25 for igniting the air-fuel mixture in the combustion chamber 11 for each cylinder. The intake passage of the engine 2 is provided with an electric throttle valve 26 (hereinafter referred to as a throttle valve) that adjusts the amount of air fed into the combustion chamber 11.

  The operation of the engine 2 is controlled by a controller 100 (setting means) (prediction means). Detection information from various sensors that detect the operating state of the engine 2 is input to the controller 100. For example, the controller detects the rotational phase of the cam shaft 18 by a cam angle sensor 30 provided in the vicinity of the cam shaft 18, and based on this cam angle, the advance amount of the opening / closing timing of the intake valve 14 (the phase of the VVT 23). Angle (hereinafter referred to as intake air VVT advance amount). The intake VVT advance amount is an advance amount of the closing timing of the intake valve 14 based on the time when the closing timing of the intake valve 14 is the most retarded timing. Further, the rotation angle of the crankshaft 9 is detected by the crank angle sensor 31, and the engine rotation speed is detected based on this detection signal. Further, the amount of intake air is detected by an air flow meter 32 provided in the vicinity of the air cleaner of the engine 2.

  The controller 100 is a control device based on a well-known microcomputer, and includes a signal input unit for inputting detection signals from various sensors (cam angle sensor 30, crank angle sensor 31, air flow meter 32, etc.), and control. An arithmetic unit that performs such arithmetic processing, a signal output unit that outputs a control signal to a device to be controlled (VVT 23, fuel injection valve 24, spark plug 25, throttle valve 26, etc.), a program and data ( And a storage unit for storing an SOI map (to be described later).

  Specifically, the controller 100 transmits a control signal to the fuel injection valve 24, and injects the fuel into two portions during four cycles. The first fuel injection is performed during the intake stroke, and the second fuel injection is performed during the compression stroke.

  Further, the controller 100 transmits a control signal to the VVT 23, the spark plug 25, and the throttle valve 26 when the engine 2 is started, and increases the intake air amount when the engine 2 is started, thereby promoting the catalyst warm-up and the catalyst. Activating AWS (Accelerated Warm-up System) that activates The operation of the AWS includes, for example, changing the intake VVT advance amount in the advance direction, the ignition timing by the spark plug 25 in the retard direction, and opening the throttle valve 26 when the engine 2 is cold started. Is performed by increasing the amount of intake air. At this time, the engine rotation speed is, for example, 1400 rpm. By this AWS operation, a large amount of exhaust gas flows into the exhaust passage, and the exhaust gas purification catalyst provided in the exhaust passage is warmed up to promote its activation. Here, the reason why the intake VVT advance amount is changed to the advance direction is to contain a large amount of air in the cylinder in order to warm up the exhaust gas purification catalyst.

  Further, at the time of BTDC 360 ° CA (predetermined timing), the controller 100 determines the current intake VVT actual advance angle amount and engine rotation speed according to the SOI map (see FIG. 3) using the intake VVT advance angle amount and engine rotation speed as parameters. Based on the above, the start timing of fuel injection by the fuel injection valve 24 (hereinafter referred to as fuel injection start timing) is set. This SOI map is created using the intake VVT advance amount, engine rotation speed, and fuel injection start timing obtained based on experimental data, and is stored in advance in the storage unit.

  Here, when the fuel injection start timing is set during the AWS operation, the intake VVT advance amount is changed to the advance direction from the set time to the set fuel injection start timing. Due to this change, there is a possibility that the fuel injection start timing based on the intake VVT advance amount is not an appropriate time, and combustion stability cannot be ensured.

  Therefore, in the present embodiment, the controller 100 predicts the intake VVT advance amount at the set fuel injection start timing during the AWS operation, and according to the SOI map, the predicted intake VVT advance amount and engine speed Based on this, the fuel injection start timing is reset.

  Hereinafter, the reset control of the fuel injection start time during the AWS operation will be described in detail with reference to FIG.

  The controller 100 predicts the intake VVT advance amount and resets the fuel injection start time immediately after the BTDC 360 ° CA time (immediately after the fuel injection start time is set), and the fuel injection start time is a requirement for the combustion stability of the engine 2. Repeated several times until the standard is met. This required standard is created using the relationship between the intake VVT advance amount, the fuel injection start timing, and the combustion stability index determined based on the experimental data, and is stored in advance in the storage unit.

  The first setting of the fuel injection start timing (described as “SOI (first time)” in FIG. 4) is performed based on the intake VVT advance amount and the engine speed at the time of BTDC 360 ° CA according to the SOI map. On the other hand, the setting of the fuel injection start timing after the second time (reset of the fuel injection start timing. In FIG. 4, “SOI (second time)” and “SOI (third time”)) are set according to the SOI map. This is performed based on the intake VVT advance amount and the engine speed at the set fuel injection start timing.

  The intake VVT advance amount at the fuel injection start timing set for the first time (described as “intake VVT advance amount at the time of SOI (first time)” in FIG. 4) is predicted by the intake VVT advance at BTDC 360 ° CA. This is performed by adding the intake VVT advance angle change amount from the time point BTDC 360 ° CA to the fuel injection start timing to the angular amount. This amount of change is calculated, for example, by multiplying the operating speed of the VVT 23 by the time from the BTDC 360 ° CA time point to the fuel injection start timing. This operating speed becomes a positive number when the intake VVT advance amount is changed in the advance direction.

  On the other hand, the prediction of the intake VVT advance amount at the fuel injection start timing set (reset) after the second time (indicated as “intake VVT advance amount at the time of SOI (second)” in FIG. 4) is For example, the intake VVT advance amount from the previously set fuel injection start timing to the currently set fuel injection start timing is added to the intake VVT advance amount at the previously set fuel injection start timing. Is done. This amount of change is calculated, for example, by multiplying the operating speed of the VVT 23 by the time from the previously set fuel injection start time to the currently set fuel injection start time.

  The fuel injection start timing resetting control operation during the AWS operation by the controller 100 will be described based on the flowchart of FIG.

  First, in step S1, in order to grasp the operating state of the engine 2, detection information is read from various sensors, and an intake VVT advance amount, an engine rotation speed, an intake air amount, and the like are detected. This detection timing is BTDC 360 ° CA. In the next step S2, the fuel injection start timing (described as “SOI” in FIG. 5) is set from the intake VVT advance amount detected in step S1 and the engine speed in accordance with the SOI map. In the next step S3, it is determined whether or not the AWS is operating.

  When the determination in step S3 is NO, this control operation ends. On the other hand, when the determination in step S3 is YES, the process proceeds to step S4, and the intake VVT advance amount at the fuel injection start timing set in step S2 or reset in step S5 is predicted. In the next step S5, the fuel injection start timing is reset from the intake VVT advance amount predicted in step S4 (indicated as “predicted intake VVT advance amount” in FIG. 5) and the engine rotation speed in accordance with the SOI map. . In the next step S6, it is determined whether or not the fuel injection start timing reset in step S5 satisfies the required standard for combustion stability of the engine 2. This required standard is represented, for example, by a correction amount of the engine load required for suppressing the change in the engine speed. If this value is within a predetermined range, it is determined that the combustion is stable. Therefore, the combustion stability is experimentally measured and stored in advance for each fuel injection start timing, and the determination is made based on the stored data.

  When the determination in step S6 is YES, this control operation ends. On the other hand, when the determination in step S6 is NO, the process returns to step S4, and the intake VVT advance amount at the fuel injection start timing (corrected fuel injection start timing) reset in step S5 is predicted.

-Effect-
As described above, according to the present embodiment, the controller 100 predicts the intake VVT advance amount at the set fuel injection start timing, and based on the predicted intake VVT advance amount, the fuel injection valve 24 Reset the fuel injection start time. For this reason, the fuel injection start timing based on the intake VVT advance amount can be set to an appropriate time even when the intake VVT advance amount is transitionally changed.

  In addition, since the controller 100 predicts the intake VVT advance amount and resets the fuel injection start timing a plurality of times, the fuel injection start based on the intake VVT advance amount is performed even when the intake VVT advance amount changes transiently. The time can be converged to an appropriate time.

  In addition, since the controller 100 predicts the intake VVT advance amount and resets the fuel injection start timing until the fuel injection start timing meets the required standard for combustion stability of the engine 2, the intake VVT advance amount Even during the change transition, the combustion stability of the engine 2 can be ensured.

  Further, the controller 100 predicts the intake VVT advance amount and resets the fuel injection start timing when the AWS is operated to increase the intake air amount when the engine 2 is started. The operation of the AWS is performed by changing the intake VVT advance amount in the advance direction. For this reason, the fuel injection start timing based on the intake VVT advance amount can be set to an appropriate time even during the AWS operation in which the intake VVT advance amount is changed in the advance direction.

(Other embodiments)
In the above embodiment, the motor-driven electric variable valve timing mechanism is used as the variable valve timing mechanism on the intake side, but a hydraulically operated variable valve timing mechanism may be used instead. Since the electric one has a higher operating speed, the present invention is particularly useful for an engine using an electric variable valve timing mechanism.

  In the above embodiment, the predetermined timing is set to BTDC 360 ° CA, but other timing may be used.

In the above-described embodiment, the prediction of the intake VVT advance amount and the resetting of the fuel injection start timing are repeated a plurality of times. However, the present invention is not limited to this, and may be performed only once, for example .

Also, in the above embodiment, the fuel injection valve 24 is, although divided and were injected twice a fuel while performing four cycles, not limited to this, for example, the fuel during the intake stroke while performing four cycles 1 You may inject only once.

  As described above, the fuel injection timing control device for an engine according to the present invention is applied to applications where it is necessary to set the fuel injection start timing to an appropriate timing even when the intake valve opening / closing timing is changed. Can do.

2 Engine 14 Intake valve 23 Variable valve timing mechanism 24 Fuel injection valve
100 controller (setting means) (prediction means)

Claims (3)

An engine fuel injection timing control device having a variable valve timing mechanism for changing the opening / closing timing of an intake valve,
Setting means for setting a fuel injection start timing by the fuel injection valve based on an actual advance angle amount of the opening / closing timing of the intake valve at a predetermined timing;
Predicting means for predicting the advance amount of the opening / closing timing of the intake valve at the fuel injection start timing set by the setting means,
The setting means is configured to reset the fuel injection start timing based on the advance amount predicted by the prediction means ,
The fuel injection by the fuel injection valve is performed during the compression stroke,
The prediction of the advance amount by the predicting means and the resetting of the fuel injection start timing by the setting means are performed when the AWS is operated to change the opening / closing timing of the intake valve in the advance direction and the ignition timing in the retard direction. A fuel injection timing control device for an engine. The fuel injection timing control device for an engine according to claim 1,
An engine fuel injection timing control apparatus according to claim 1, wherein the prediction of the advance amount by the prediction means and the resetting of the fuel injection start timing by the setting means are repeated a plurality of times. The fuel injection timing control device for an engine according to claim 1 or 2,
The prediction of the advance amount by the predicting means and the resetting of the fuel injection start timing by the setting means are performed until the fuel injection start timing satisfies the requirement standard for combustion stability of the engine. Fuel injection timing control device.

Images