JP2018155224A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine performing engine start control to suppress vibration of a car body in starting an engine.SOLUTION: In an internal combustion engine 10 including an ignition device 14 for igniting an air fuel mixture in a cylinder, an ECU 34 controls the ignition device 14 so that an ignition timing for a second explosion is advanced with respect to an ignition timing for a first explosion, in a case when an engine rotating speed (first explosion rotating speed) Ne1 in the first explosion in starting an engine, is higher than a lower limit value Neth of the engine rotating speed Ne to keep an explosion interval between the first explosion and the second explosion, away from an engine rigid body resonance period by the advance of the ignition period.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device for an internal combustion engine.

  Patent Document 1 discloses a control device for an internal combustion engine in which idling stop control is performed. More specifically, in Patent Document 1, when the engine restart is performed by the idling stop control in a state where the drive range of the automatic transmission (AT) (the range selected during vehicle travel) is selected, It is disclosed that a starting shock such as a jump occurs due to the occurrence of acceleration in the front-rear direction. Further, Patent Literature 1 discloses that the ignition timing is retarded in order to perform engine restart while reducing such a start shock.

JP 2002-242724 A

  When the engine is started, if the explosion interval between the first explosion and the second explosion is close to the engine rigid body resonance period, there is a concern that the vibration of the vehicle body increases. It is desirable that the engine start control includes measures for suppressing vehicle body vibration in consideration of such a viewpoint.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine in which engine start control is performed to suppress vibration of the vehicle body at the time of engine start.

  An internal combustion engine control apparatus according to the present invention controls an internal combustion engine including an ignition device that ignites an air-fuel mixture in a cylinder. The controller controls the engine rotation speed when the first explosion is performed at the time of starting the engine so that the explosion interval between the first explosion and the second explosion is separated from the engine rigid body resonance period by the advance of the ignition timing. When the engine speed is lower than the lower limit value, the ignition device is controlled so that the ignition timing for the second explosion is advanced from the ignition timing for the first explosion.

  According to the present invention, it is possible to suppress the vibration of the vehicle body by keeping the explosion interval (ignition interval) between the first explosion and the second explosion away from the engine rigid body resonance period by the advance angle of the ignition timing of the second explosion. It becomes like this. Furthermore, engine startability can be improved by improving the explosion torque.

It is a figure for demonstrating schematically the system configuration | structure of the vehicle provided with the internal combustion engine which concerns on embodiment of this invention. It is a flowchart which shows the routine of the process regarding the engine starting control (ignition timing control) which concerns on embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. However, in the embodiment shown below, when referring to the number of each element, quantity, quantity, range, etc., unless otherwise specified or clearly specified in principle, the reference However, the present invention is not limited to these numbers. Further, the structures, steps, and the like described in the embodiments below are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle.

1. Example of System Configuration According to Embodiment FIG. 1 is a diagram for schematically explaining the system configuration of a vehicle 1 including an internal combustion engine 10 according to an embodiment of the present invention. A vehicle 1 shown in FIG. 1 is a front wheel drive vehicle (FF vehicle) as an example, and includes a spark ignition type internal combustion engine 10 as a power source. As an example, the internal combustion engine 10 is an in-line four-cylinder engine.

  The internal combustion engine 10 includes a fuel injection valve 12 and an ignition device 14. The fuel injection valve 12 is disposed in each cylinder and injects fuel directly into the cylinder. Fuel may be injected into the intake port. The ignition device 14 ignites the air-fuel mixture in the cylinder using an ignition plug disposed in each cylinder. The internal combustion engine 10 includes a crank angle sensor 16 and a cam angle sensor 18. The crank angle sensor 16 outputs a signal corresponding to the rotational position of the crankshaft 20. According to the crank angle sensor 16, the engine rotation speed can be acquired and the ignition timing can be determined. Further, the cam angle sensor 18 can determine the cylinder in which ignition is performed.

  Torque generated by the internal combustion engine 10 (crankshaft 20 torque) is transmitted to the drive wheels 26 via the transmission 22 and the differential gear 24. The vehicle 1 also includes a motor generator (hereinafter also referred to as “MG”) 28. The MG 28 is connected to the crankshaft 20. In the configuration shown in FIG. 1, the MG 28 is connected to the crankshaft 20 via a belt 30 as an example.

  The MG 28 is electrically connected to the battery 32. The MG 28 has a function as a generator that converts the torque of the crankshaft 20 generated by combustion into electric power. The battery 32 stores the electric power generated by the MG 28. The MG 28 also has a function as an electric motor that rotationally drives the crankshaft 20 using the electric power of the battery 32.

  The system according to this embodiment includes an electronic control unit (ECU) 34. The ECU 34 includes at least an input / output interface, a memory, and a processor, and is mounted on the vehicle 1 in order to control the operation of the internal combustion engine 10. In addition to the crank angle sensor 16 and the cam angle sensor 18 described above, the ECU 34 is electrically connected with various sensors for acquiring the operation state of the vehicle 1 including the operation state of the internal combustion engine 10. The ECU 34 is electrically connected to various actuators for controlling the operation of the internal combustion engine 10 such as the fuel injection valve 12, the ignition device 14, and the MG 28 described above. The memory stores various control programs and maps for controlling the operation of the internal combustion engine 10. The processor reads the control program from the memory and executes it, and generates operation signals for various actuators based on the acquired sensor signals. Thereby, the function of the “control device for an internal combustion engine” according to the present embodiment is realized.

2. Engine control according to embodiment 2-1. S & S Control The engine control performed by the ECU 34 includes S & S (Stop & Start) control. In the S & S control, when a predetermined engine automatic stop condition is satisfied while the vehicle 1 is temporarily stopped, the operation of the internal combustion engine 10 is automatically stopped by stopping the fuel supply, and then a predetermined engine start condition is satisfied. The internal combustion engine 10 is restarted. The engine restart can be performed by rotationally driving the crankshaft 20 using the MG 28, and can also be performed using so-called ignition start control.

2-2. Problems when starting the engine When starting the engine, it is necessary to suppress vibration of the vehicle body (more specifically, floor vibration). In particular, in a vehicle in which the S & S control as described above is executed, floor vibration is easily noticeable when the engine is restarted from a stationary state (a state where the vehicle is stopped). If the idling stop function is canceled while avoiding such floor vibration, the merchantability of the vehicle is lowered and it becomes difficult to sufficiently achieve fuel saving.

2-3. Characteristic engine start control The main factors of floor vibration are as follows. That is, the engine rigid resonance frequency is typically designed to avoid the cranking rotational speed and the normal rotational speed region (the rotational speed region equal to or higher than the idle rotational speed). Under such a design, when the engine rotational speed passes through a specific rotational speed region (a rotational speed region that is equal to or higher than the cranking rotational speed and lower than the idle rotational speed), it is easy to induce engine rigid body resonance. As a result, floor vibration tends to increase.

  Regarding the explosion interval, if the explosion interval between the first explosion (initial explosion) and the second explosion is close to the engine rigid body resonance cycle (about 100 ms for FF vehicles) when starting the engine, there is a concern that the floor vibration will increase. The Therefore, in the present embodiment, the following start control is executed in order to suppress floor vibration when the engine is restarted from the S & S control.

  In other words, in the present embodiment, the engine rotation speed (hereinafter also referred to as “initial explosion rotation speed Ne1”) when the first explosion is performed at the time of engine restart is determined by the advance of a predetermined amount of ignition timing. When the explosion interval between the first explosion and the second explosion is higher than a predetermined value (lower limit) Neth of the engine speed Ne that can be kept away from the engine rigid body resonance period, the ignition timing (ignition angle) for the second explosion ) Is controlled so that the ignition timing is advanced from the ignition timing for the first explosion. The second explosion is not a second explosion of the same cylinder, but an explosion of a cylinder in which an explosion is performed following the cylinder in which the first explosion is performed.

  More specifically, the ignition timing for the first explosion is set to the most retarded value within a predetermined ignition timing setting range in order to reduce vibration due to a decrease in explosion torque. In addition, when the initial explosion rotational speed Ne1 is higher than the predetermined value Neth, the ignition timing for the second explosion is advanced by a predetermined amount (for example, 5 ° CA) from the most retarded value.

  In the above case (Ne1> Neth), in order to shorten the time until the engine complete explosion by improving the explosion torque, not only the second explosion but also the explosion after the second during the engine start-up. Also, the above-mentioned advance angle is continued.

  On the other hand, when the initial explosion speed Ne1 is equal to or lower than the predetermined value Neth, the ignition timing for the second explosion and the explosion after the second during the engine start is the same as the most retarded angle value at the time of the first explosion. Maintained at.

2-4. Processing of ECU FIG. 2 is a flowchart showing a processing routine relating to engine start control (ignition timing control) according to the embodiment of the present invention. This routine is repeatedly executed during engine automatic stop by S & S control.

  In the routine shown in FIG. 2, the ECU 34 first determines whether or not engine restart is started by S & S control (step S100). As a result, when this determination is not satisfied, the process at the time of starting the current routine is immediately terminated.

  On the other hand, when the determination in step S100 is established (when engine restart is started), the ECU 34 determines whether or not the initial explosion rotational speed Ne1 is higher than a predetermined value Neth (step S102). As the initial explosion rotational speed Ne1 increases, the amount of change in the explosion interval (time-based value) that accompanies a change in the ignition timing by a predetermined amount increases. The predetermined value Neth is an engine in which the explosion interval between the first explosion (first explosion) and the second explosion is kept away from the engine rigid resonance period by advancing the ignition timing by a predetermined amount (for example, 5 ° CA). This is a value set in advance as the lower limit value of the rotational speed Ne.

  When the determination in step S102 is established (Ne1> Neth), the ECU 34 sets the ignition timing for the second and subsequent explosions during engine startup to a value advanced from the most retarded value by the predetermined amount. (Step S104).

  On the other hand, if the determination in step S102 is not satisfied (Ne1 ≦ Neth), the ECU 34 sets the latest ignition timing for the second and subsequent explosions during engine start (same as the value for the first explosion). The angle value is set (step S106).

2-5. 2. Effect of Engine Start Control According to Embodiment According to the processing of the routine shown in FIG. 2 described above, when engine restart speed Ne1 is higher than a predetermined value Neth during engine restart by S & S control, that is, When the explosion interval between the first explosion and the second explosion is kept away from the engine rigid body resonance period by the advance of the ignition timing, the ignition timing for the second explosion is advanced. As a result, the floor vibration can be suppressed by keeping the explosion interval (ignition interval) between the first explosion and the second explosion away from the engine rigid resonance period (shorter than the engine rigid resonance period). Furthermore, engine startability can be improved by improving the explosion torque.

  Further, according to the above processing, the ignition timing for the explosion after the second time during engine startup is also advanced. As a result, the floor vibration is suppressed by controlling the explosion interval between the first explosion and the second explosion, and the time until the engine complete explosion can be shortened by improving the explosion torque in the subsequent explosion.

  Further, according to the above processing, when the initial explosion rotational speed Ne1 is equal to or lower than the predetermined value Neth, the ignition timing advance for the second (and subsequent) explosion is not executed, and the most retarded value is obtained. used. As a result, if the explosion interval between the first explosion and the second explosion cannot be kept away from the engine rigid body resonance period due to the advance of the ignition timing, the floor vibration is reversed by improving the explosion torque due to the advance of the ignition timing. Can be avoided. In this case, floor vibration can be suppressed by lowering the explosion torque that becomes the vibration generating force by using the most retarded angle value during engine start.

  By the way, in the above-described embodiment, the engine start control of the present embodiment (that is, the ignition timing for the second and subsequent explosions according to the initial explosion rotational speed Ne1) for the engine restart by the S & S control. An example in which the above control is applied) was given. However, such engine start control is not limited to when the engine is restarted by S & S control, but may be applied at the time of normal engine start when starting operation of the vehicle.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Internal combustion engine 12 Fuel injection valve 14 Ignition device 16 Crank angle sensor 18 Cam angle sensor 20 Crankshaft 26 Drive wheel 28 Motor generator (MG)
30 Belt 32 Battery 34 Electronic Control Unit (ECU)

Claims (1)

A control device for an internal combustion engine comprising an ignition device for igniting an air-fuel mixture in a cylinder,
The controller controls the engine rotation speed when the first explosion is performed at the time of starting the engine so that the explosion interval between the first explosion and the second explosion is separated from the engine rigid body resonance period by the advance of the ignition timing. The ignition device is controlled so that the ignition timing for the second explosion is advanced from the ignition timing for the first explosion when the engine rotation speed is higher than a lower limit value of the engine speed. A control device for an internal combustion engine.

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