Engine Control Unit

Abstract

To secure excellent combustion under various operation conditions.SOLUTION: A controller of an engine device comprises: an engine 10 comprises a combustion chamber C comprising a main chamber 1 and a sub-chamber 11, an injection device 9 that supplies fuel to the combustion chamber C, and an ignition device 4 facing into the sub-chamber; means of detecting or predicting occurrence of knocking; and control means of performing control to avoid knocking. The control means performs fuel injection reduction control to reduce an injection amount of fuel of sub-chamber injection for supplying fuel to the sub-chamber 11 by the injection device 9 when the occurrence of knocking is detected or predicted, and performs ignition energy increase control to increase ignition energy of an air-fuel mixture by the ignition device 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an engine control device. [Background technology]

[0002] Conventionally, there have been proposed lean-burn engines that burn a mixture with a leaner fuel ratio (excess air relative to fuel) than the theoretical air-fuel ratio. In addition, in order to better burn the lean mixture, a pre-chamber engine has been proposed that has a main chamber and a pre-chamber as combustion chambers. In the pre-chamber engine, a communication passage is provided in a partition wall that separates the main chamber from the pre-chamber, and a mixture formed by fuel injected into the main chamber is supplied to the pre-chamber through the communication passage and ignited by a spark plug in the pre-chamber. When a flame is formed in the pre-chamber, the flame propagates to the main chamber through the communication passage and ignites the mixture in the main chamber. This is said to enable operation with a leaner air-fuel ratio and improve fuel efficiency (see, for example, Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4389777 [Patent Document 2] International Publication No. 2020 / 196206 Summary of the Invention [Problem to be solved by the invention]

[0004] In general engines, when knocking occurs under high load, the ignition timing is retarded to reduce the pressure inside the cylinder, thereby preventing knocking. However, in the case of a pre-chamber engine, retarding the ignition timing creates a lean environment in the pre-chamber, which can lead to unstable ignition of the mixture in the pre-chamber. In addition, there is a need for a way to ensure good combustion while avoiding knocking under various operating conditions that change from moment to moment.

[0005] Therefore, an object of the present invention is to ensure good combustion under various operating conditions. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an engine including a combustion chamber having a main chamber surrounded by an inner circumferential surface of a cylinder, an inner surface of a cylinder head, and a top surface of a piston, an auxiliary chamber separated from the main chamber by a partition and formed at the end of the main chamber on the cylinder head side, and a communication passage provided in the partition connecting the main chamber with the auxiliary chamber, an injection device for supplying fuel to the combustion chamber, and an ignition device facing the auxiliary chamber and igniting the air-fuel mixture in the auxiliary chamber, a means for detecting or predicting the occurrence of knocking in the engine, and a control means for performing control to avoid the knocking, wherein the control means employs an engine control device that, when the occurrence of knocking is detected or predicted, performs fuel injection reduction control to reduce the fuel injection amount of auxiliary chamber injection that supplies fuel to the auxiliary chamber by the injection device, and performs ignition energy increase control to increase the ignition energy of the mixture by the ignition device.

[0007] Here, the control means may be configured to perform ignition timing retard control for retarding the timing of ignition of the air-fuel mixture by the ignition device when the occurrence of knocking is detected or predicted.

[0008] In this case, the ignition energy increase control may be configured to set an increase amount of the ignition energy to be greater as the retard amount of the ignition timing in the ignition timing retard control increases.

[0009] When the ignition timing retard control is performed, a configuration can be adopted in which an injection timing retard control is performed to retard the injection timing of the sub-chamber injection by the injection device.

[0010] In each of these aspects, a configuration can be adopted in which a means for detecting torque fluctuation or combustion fluctuation in the engine is provided, and the ignition energy increase control is performed only when the torque fluctuation or combustion fluctuation exceeds a predetermined value.

[0011] In each of these aspects, a configuration can be adopted in which an air-fuel ratio detection means is provided for detecting or estimating the air-fuel ratio in the main chamber, and the control means, if the air-fuel ratio is richer than a predetermined value when the occurrence of knocking is detected or predicted, performs the ignition timing retard control and does not perform the ignition energy increase control, but reduces the amount of fuel injection of main chamber injection that supplies fuel from the injection device to the main chamber, and if the detection or prediction of the occurrence of knocking continues, further performs the ignition timing retard control and performs the ignition energy increase control. Effect of the Invention

[0012] According to the present invention, good combustion can be ensured under various operating conditions. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a vertical cross-sectional view of a pre-combustion chamber engine. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Figure 3A] FIG. 2 is a vertical cross-sectional view showing the combustion state of a pre-combustion chamber engine. [Figure 3B] FIG. 2 is a vertical cross-sectional view showing the combustion state of a pre-combustion chamber engine. [Figure 3C] FIG. 2 is a vertical cross-sectional view showing the combustion state of a pre-combustion chamber engine. [Figure 4] FIG. 4 is a graph showing control under normal operating conditions. [Diagram 5] FIG. 4 is a graph showing the control of the present invention. [Figure 6] FIG. 4 is a graph showing the control of the present invention. [Figure 7] 1 is a schematic diagram showing an example of a vehicle according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. This embodiment is a hybrid vehicle 60 (hereinafter simply referred to as vehicle 60). A main part of an engine 10 mounted on the vehicle 60 is shown in FIGS.

[0015] The vehicle 60 includes a battery 50 used mainly as a power source for traveling, and two rotating electric machines 30, 40. One of the rotating electric machines 30 (hereinafter referred to as the first rotating electric machine 30) functions as a starter, and the engine 10 starts when the first rotating electric machine 30 operates. The other rotating electric machine 40 (hereinafter referred to as the second rotating electric machine 40) is a motor that supplies driving force for traveling. The first rotating electric machine 30 also functions as a generator that generates electricity using the driving force of the engine 10 (see FIG. 7).

[0016] The vehicle 60 is a hybrid vehicle in which three types of driving modes are set: an electric driving mode (EV mode), a series driving mode, and a parallel driving mode. An electronic control unit 20 provided in the vehicle 60 selects an optimal driving mode according to the state and driving state of the vehicle 60 at that time, a request from the driver, and the like. The engine 10, the first rotating electric machine 30, the second rotating electric machine 40, and the like are controlled according to the selected driving mode. In the embodiment, the vehicle 60 is assumed to be a plug-in hybrid car (PHEV vehicle) in which the battery 50 can be directly charged using a plug from a household outlet or the like.

[0017] The first rotating electric machine 30 is a motor-generator that functions both as an electric motor (motor) and as a generator (generator). When starting the engine 10, the first rotating electric machine 30 functions as an electric motor for a starter. At this time, the first rotating electric machine 30 uses electric power from a battery 50 or a separately installed auxiliary battery. When the engine 10 is in operation, the first rotating electric machine 30 exerts a function of generating electric power by the driving force of the engine 10. The electric power generated by the first rotating electric machine 30 is supplied to the second rotating electric machine 40 and the battery 50. The rotating shaft of the first rotating electric machine 30 is connected to the crankshaft of the engine 10 via an endless member such as a belt, a gear, or the like. When the engine 10 is in operation, the first rotating electric machine 30 is usually rotated together with the rotation of the crankshaft.

[0018] The second rotating electric machine 40 is provided as a drive source for driving the vehicle 60. The second rotating electric machine 40 is driven by using electric power stored in the battery 50 and electric power generated by the first rotating electric machine 30. As shown in FIG. 6, there are examples in which only one second rotating electric machine 40 is provided on the front side, and examples in which one is provided on the front side and one on the rear side, and the number and locations of the second rotating electric machine 40 are various. The second rotating electric machine 40 also functions as a generator that generates regenerative electric power mainly during coasting.

[0019] A control unit (not shown) including an inverter that converts between DC and AC is provided between the first rotating electric machine 30 and the second rotating electric machine 40 and the electronic control unit 20. The rotation speeds of the first rotating electric machine 30 and the second rotating electric machine 40 when they are driven are controlled by the electronic control unit 20 via the inverter.

[0020] The engine 10 is a gasoline engine. Depending on the driving mode, the rotation of the crankshaft of the engine 10 is switched between a state in which it is transmitted to the drive wheels via a torque converter, a continuously variable transmission, a clutch, a differential, etc., and a state in which the transmission is interrupted.

[0021] The battery 50 is a high-voltage power supply capable of storing (charging) the electric power generated by the first rotating electric machine 30 and the electric power regenerated by the second rotating electric machine 40, and discharging the stored electric power. The battery 50 is mainly used as a power supply for supplying electric power for traveling. In this embodiment, the battery 50 is compatible with a plug-in hybrid car (PHEV vehicle) and is capable of external charging, such as charging from a power supply outside the vehicle, for example, a household AC power supply (normal charging) or charging from a high-voltage DC power supply (fast charging).

[0022] The vehicle 60 is equipped with a steering wheel, a brake pedal, an accelerator pedal, and the like that are operated by the driver. The brake pedal is provided with a brake sensor that detects the force with which the driver presses the brake pedal. In addition, the accelerator pedal is provided with an accelerator position sensor that detects the amount of depression of the accelerator pedal by the driver. Brake information detected by the brake sensor and accelerator information detected by the accelerator position sensor are sent to the electronic control unit 20. In addition, the vehicle 60 is equipped with a vehicle speed sensor that is provided on the axle or the like and detects the traveling speed of the vehicle 60. Vehicle speed information detected by the vehicle speed sensor is also sent to the electronic control unit 20.

[0023] The vehicle 60 is also provided with an engine speed sensor that detects the speed of the engine 10, speed sensors that detect the speeds of the first rotating electric machine 30 and the second rotating electric machine 40, a voltage sensor that detects the cell voltage of the battery 50, a current sensor that detects the current of the battery 50, etc. The vehicle 60 is also provided with a water temperature sensor that detects the temperature of the cooling water for the engine 10, and an oil temperature sensor that detects the temperature of the engine oil. Information from these sensors is also sent to the electronic control unit 20.

[0024] The electronic control unit 20 includes an engine control section 21 that mainly controls the engine 10, and a vehicle control section 22 that controls the operation of the entire hybrid vehicle. The electronic control unit 20 is a collection of electronic control devices (computers) that control various devices equipped in the vehicle 60. An interface, a processor, a memory, and the like that are connected to each other via a bus are built in the electronic control unit 20. The contents of the control executed by the engine control section 21 and the vehicle control section 22 are stored in advance in the memory, and new data is stored as the control progresses, and these data are utilized for subsequent control. The electronic control unit 20 selects and switches between driving modes such as an electric driving mode (a mode in which the vehicle runs only on the driving force of the second rotating electric machine 40), a series driving mode (a mode in which the vehicle runs only on the driving force of the second rotating electric machine 40 using the driving force of the engine 10 to operate the first rotating electric machine 30 to generate electricity, and the generated electricity is used to run the vehicle 60 only on the driving force of the second rotating electric machine 40), and a parallel driving mode (a mode in which the vehicle 60 runs on the driving force of the engine 10 and, if necessary, the driving force of the second rotating electric machine 40 is used to assist the vehicle 60 in running).

[0025] The engine 10 is an engine with a pre-chamber. FIG. 1 and FIG. 2 show the main part of one cylinder 2 of the engine 10. The engine 10 is provided with an intake passage (intake port) 5 for feeding air into the combustion chamber C, an exhaust passage (exhaust port) 6 drawn from the combustion chamber C, an injector 9 for supplying fuel to the combustion chamber C, and the like. An opening 5a of the intake passage 5 to the combustion chamber C is opened and closed by an intake valve 7. An opening 6a of the exhaust passage 6 to the combustion chamber C is opened and closed by an exhaust valve 8. In the embodiment, the injector 9 includes both a direct injection type fuel injector 9a that injects fuel directly into the combustion chamber C and a port injection type fuel injector 9b that injects fuel into the intake passage 5. In the drawings, only members and means directly related to this invention are shown, and other members and the like are omitted. The number of cylinders provided in the engine 10 can be freely set according to the specifications of the vehicle 60 and the engine 10, and may be, for example, three cylinders, four cylinders, or any other number of cylinders.

[0026] As shown in Fig. 1, the combustion chamber C includes a main chamber 1 surrounded by an inner peripheral surface 2a of a cylinder (cylinder block) 2, an inner surface (lower surface) of a cylinder head 13, and a top surface 3a of a piston 3, and an auxiliary chamber 11 separated from the main chamber 1 and formed at an end of the main chamber 1 on the cylinder head 13 side. The combustion chamber C also includes a partition wall 14 separating the main chamber 1 from the auxiliary chamber 11, and a communication passage 12 consisting of a small hole penetrating the partition wall 14. The communication passage 12 connects the space of the main chamber 1 to the space of the auxiliary chamber 11. The auxiliary chamber 11 is also provided with an ignition device 4 that ignites the air-fuel mixture in the auxiliary chamber 11 by generating an electric spark.

[0027] The operating state of the engine 10 will be described. First, as shown in FIG. 3A, air is introduced from the intake passage 5 into the main chamber 1, and a lean mixture is formed in the main chamber 1 by the injection of fuel from the injector 9. The lean mixture is pushed from the main chamber 1 into the auxiliary chamber 11 during the compression stroke when the piston 3 rises, as shown in FIG. 3B. Here, as shown in FIG. 3C, a spark is generated at the electrode 4a of the ignition device 4, and the mixture introduced into the auxiliary chamber 11 is ignited. When the mixture is ignited in the auxiliary chamber 11, the flame is jetted to the main chamber 1 side through the communication passage 12, and becomes a high-speed jet flame. This jet flame promotes the combustion of the mixture even when the mixture is lean (including when a large amount of exhaust gas recirculation gas is introduced). The gas after the combustion is discharged to the outside through the exhaust passage 6. In the embodiment, fuel is injected twice during one combustion cycle. That is, a first injection is performed to mainly supply fuel to the main combustion chamber 1, and a second injection is performed to mainly supply fuel to the pre-compression chamber 11. The first fuel injection is performed during the intake stroke, which will be referred to hereinafter as the main chamber injection. The second fuel injection is performed during the compression stroke, which will be referred to hereinafter as the pre-compression chamber injection. In this embodiment, the main chamber injection is mainly performed by the port injection type fuel injection device 9b, and the pre-compression chamber injection is mainly performed by the direct injection type fuel injection device 9a.

[0028] Here, as described above, in a general engine, when knocking occurs under high load, the ignition timing is retarded to reduce the pressure inside the cylinder, thereby avoiding knocking. However, in a pre-chamber engine, the flame propagates quickly in the combustion chamber C, so the occurrence of knocking is not affected much by the engine speed, but is affected greatly by the engine load. For example, in a region where the engine load is low, the combustion cycle fluctuation tends to be large regardless of the engine speed. For this reason, the amount of fuel injection (in the embodiment, both the direct injection fuel injection device 9a and the port injection fuel injection device 9b are provided, and therefore, the amount of fuel injection by the direct injection fuel injection device 9a in particular) is increased. Also, for example, in a region where the engine load is high, the occurrence of knocking tends to be noticeable regardless of the engine speed. For this reason, the amount of fuel injection (in the embodiment, both the direct injection fuel injection device 9a and the port injection fuel injection device 9b are provided, and therefore, the amount of fuel injection by the direct injection fuel injection device 9a in particular) is decreased.

[0029] The electronic control unit 20 includes a means for detecting or predicting the occurrence of knocking based on the relationship between the engine speed and engine load of the engine 10 at that time. Such a means for detecting or predicting the occurrence of knocking is hereinafter referred to as a knocking detection and prediction means. As the knocking detection and prediction means, a device for detecting or predicting the occurrence of knocking by detecting torque fluctuations or combustion fluctuations due to vibrations of the engine 10, changes in cylinder pressure, or changes in the rotational angular velocity of the crankshaft, etc., may also be used. An operating region in which the occurrence of knocking is detected or predicted is hereinafter referred to as a knocking occurrence region.

[0030] The engine 10 of the embodiment is based on a lean air-fuel mixture with a lower fuel ratio (lean fuel) than the theoretical air-fuel ratio (A / F=14.7). The air-fuel ratio of the lean air-fuel mixture is set as an initial value. The air-fuel ratio is the air / fuel ratio, and is expressed as a dimensionless quantity obtained by dividing the air mass by the fuel mass. The electronic control unit 20 has a function of estimating the air-fuel ratio in the auxiliary chamber 11 and the air-fuel ratio of the entire combustion chamber C, etc., based on information from sensors around the engine 10.

[0031] In the knocking occurrence region, the control means provided in the electronic control unit 20 performs control to avoid knocking. First, when the knocking occurrence region is entered (when the occurrence of knocking is detected or predicted), the control means performs fuel injection reduction control to reduce the amount of fuel injected by the direct fuel injection device 9a in the pre-chamber injection, thereby avoiding knocking. However, if the amount of fuel injection is reduced, the combustion chamber C and the pre-chamber 11 become lean environments, and the period during which the ignition timing can be set is extremely limited.

[0032] FIG. 4 shows an air-fuel ratio curve G, which indicates the change in the air-fuel ratio before the fuel injection amount is reduced, a post-reduced air-fuel ratio curve F, which indicates the change in the air-fuel ratio after the fuel injection amount is reduced, the fuel injection timing C (by direct injection), and the optimum ignition timing D. The air-fuel ratio curve G shows that over the course of one combustion cycle, the air-fuel ratio in the pre-chamber 11 starts to decrease (the amount of fuel increases) from the injection timing C, and the air-fuel ratio becomes minimum (the amount of fuel becomes maximum) at approximately the optimum ignition timing D, and as the piston 3 approaches top dead center E, the air-fuel ratio increases (the amount of fuel decreases). Here, the point where the air-fuel ratio in the pre-chamber 11 becomes minimum (richest) is the optimum ignition timing D. The range surrounded by the upper limit line A of the amount of fuel in the pre-chamber that can be ignited and the air-fuel ratio curve G in the pre-chamber 11, i.e., the range L from point s to point a, is A However, when the fuel injection amount is reduced and the air-fuel ratio curve G is shifted to the reduced air-fuel ratio curve F, the range of suitable ignition timing for realizing good combustion, that is, the range L from point s to point a, A The size of the fuel becomes smaller and smaller, making it more likely that combustion will become unstable.

[0033] Therefore, when the knocking occurrence region is entered (when the occurrence of knocking is detected or predicted), the control means performs fuel injection reduction control as well as ignition energy increase control to increase the ignition energy to the mixture by the ignition device 4. When the ignition energy is increased, the upper limit line A of the pre-chamber air-fuel ratio at which ignition is possible shifts to the modified upper limit line B which is on the leaner side (lower side) than the upper limit line A on the graph. For this reason, the range of appropriate ignition timing for realizing good combustion is defined as the range surrounded by the modified upper limit line B and the reduced air-fuel ratio curve F, that is, the range L from point s' to point a'. B This allows the range of ignition timing to be expanded, ensuring stable ignition.

[0034] Conventionally, ignition energy was constant regardless of the ignition timing (crank angle). However, in this invention, when the amount of fuel injection is reduced to avoid knocking, the ignition energy is increased, thereby making it possible to ensure good and stable combustion. However, if the ignition energy is constantly increased, it is possible that the ignition device 4 (spark plug) will melt or that the thermal efficiency of the engine 10 will decrease due to the use of a lot of electricity. For this reason, when increasing the ignition energy, it is necessary to limit the increase in energy to the minimum necessary.

[0035] In the ignition energy increase control, the ignition energy C2 (referred to as the second ignition energy C2) corresponding to the start of the control is set relatively large compared to the ignition energy C1 (referred to as the first ignition energy C1) in the steady state before the start of the control. Here, (Second ignition energy C2) = (First ignition energy C1) × α In this case, α>1, and the value of α can be set to, for example, 1.1, 1.2, 1.3, 1.4, . . . , or the like, which is the minimum required value according to the operating state.

[0036] Here, the range in which the ignition timing can be set is the range L from point s' to point a'. BSince the control means has expanded the range to 100%, the control means can perform ignition timing retard control to retard the ignition timing of the air-fuel mixture by the ignition device 4. By performing ignition timing retard control, knocking can be avoided more reliably.

[0037] In the ignition timing retard control, the ignition timing is retarded from the ignition timing B1 (referred to as the first ignition timing B1) in the steady state before the start of the control to the ignition timing B2 (referred to as the second ignition timing B2) corresponding to the start of the control. The first ignition timing B1 may be between points s and a shown in FIG. 5, that is, a timing at which the air-fuel ratio in the auxiliary combustion chamber 11 is below the numerical value of the upper limit line A (richer side (upper side) than line A on the graph) and the mixture is smoothly ignited. Usually, the first ignition timing B1 is set to coincide with the timing D (optimum ignition timing D) at which the air-fuel ratio in the auxiliary combustion chamber 11 is the richest, thereby improving the thermal efficiency. It is desirable that the first ignition timing B1 is as close to the optimum ignition timing D as possible. The second ignition timing B2 may be between points s' and a' shown in FIG. 5, that is, a timing when the air-fuel ratio in the auxiliary chamber 11 is below the value of the modified upper limit line B (on the richer side (upper side) than line B on the graph) and the air-fuel mixture is smoothly ignited.

[0038] Furthermore, when performing ignition timing retard control, injection timing retard control for retarding the fuel injection timing by the injector 9 (particularly the direct injection fuel injector 9a) may be performed at the same time. For example, when retarding the ignition timing by 5 degrees in crank angle, there is a method for retarding the fuel injection timing by the same angle as the retard amount of the ignition timing, such as retarding the fuel injection timing by 5 degrees in crank angle. There is also a method for retarding the fuel injection timing by an angle smaller than the retard amount of the ignition timing, or a method for retarding the fuel injection timing by an angle larger than the retard amount of the ignition timing. This makes it possible to increase the amount of fuel remaining around the ignition device 4 at the ignition timing.

[0039] Also, when performing ignition timing retard control, a method may be adopted in which the increase in ignition energy in ignition energy increase control is set to a larger amount as the retard amount of the ignition timing increases. Figure 6 shows the set ignition timing and the magnitude of ignition energy set corresponding to the ignition timing. Graph H showing the magnitude of ignition energy is set to a minimum value at reference point c located near or on the retard side of the apex b (optimum ignition timing D) of air-fuel ratio curve G, and the ignition energy is set to increase as the ignition timing is shifted to the retard side or advance side from that point. In addition, a method may be adopted in which the ratio (%) of the increase in ignition energy to the original ignition energy is proportional to the amount of retardation (deg) of the crank angle, for example, by setting the coefficient α of the increase in ignition energy to 1.05 when the ignition timing is retarded by 5 (deg) of crank angle, and by setting the coefficient α of the increase in ignition energy to 1.075 when the ignition timing is retarded by 7.5 (deg) of crank angle.

[0040] Furthermore, if the vehicle 60 is equipped with a means for detecting torque fluctuation or combustion fluctuation in the engine 10 (if the knocking detection and prediction means detects torque fluctuation or combustion fluctuation, it may be used), a method may be adopted in which, using information on the torque fluctuation or combustion fluctuation, it is determined whether or not to perform ignition energy increase control, and if so, the degree of increase. For example, a method may be considered in which the ignition energy increase control is performed only when the torque fluctuation or combustion fluctuation exceeds a predetermined value. Here, the predetermined value is a lower limit of the torque fluctuation or combustion fluctuation at which it is possible to recognize that the combustion of the mixture in the combustion chamber C is unstable, and the numerical value is obtained in advance by a simulation or the like. In addition, there is a method in which, based on the numerical value of the torque fluctuation or combustion fluctuation at that time, the difference between each numerical value and a predetermined value (each numerical value>predetermined value) is based on the difference, and the coefficient α of the increase in ignition energy is increased as the difference increases.

[0041] Also, a method of preventing misfire at the ignition timing after retarding by changing the ignition pattern during ignition timing retard control is conceivable. Examples of changing the ignition pattern include a method of promoting ignition by performing multiple ignitions during one combustion cycle, a method of overlapping sparks by performing re-discharge using another coil after one discharge during one combustion cycle (boost), and a method of creating a state with a higher current value by shortening the discharge time in the ignition device 4 to promote ignition, which increases the total ignition energy during one combustion cycle.

[0042] Furthermore, when the knocking occurrence region is entered (when the occurrence of knocking is detected or predicted), if the air-fuel ratio in the main chamber 1 is richer than a predetermined value, the control means performs ignition timing retard control and does not perform ignition energy increase control, but reduces the amount of fuel injection of the main chamber injection that supplies fuel to the main chamber 1 from the port injection type fuel injection device 9b, and if the detection or prediction of the occurrence of knocking continues, performs further ignition timing retard control and ignition energy increase control. Here, the predetermined value may be any value that can determine that the inside of the main chamber 1 is rich, but may be, for example, the value of the theoretical air-fuel ratio. When the environment in the main chamber 1 is relatively rich, first, the ignition timing retard control and the reduction in the amount of fuel injection of the main chamber injection are limited to see whether knocking can be avoided, thereby minimizing the opportunity for ignition energy increase control.

[0043] At this time, the reason why the reduction in the fuel injection amount is limited to main chamber injection (mainly by port injection fuel injection device 9b) is that when both direct injection fuel injection device 9a and port injection fuel injection device 9b are provided, the proportion of fuel injected from direct injection fuel injection device 9a is about 5 to 10% of the total, and direct injection fuel injection device 9a does not contribute much to creating a rich environment in main chamber 1. Here, if the detection or prediction of the occurrence of knocking continues, further ignition timing retard control is performed and ignition energy increase control is performed to reliably avoid knocking.

[0044] In the above embodiment, the injection device 9 is configured to include both the direct injection fuel injection device 9a and the port injection fuel injection device 9b, but the present invention is not limited to this embodiment, and a configuration in which only the direct injection fuel injection device 9a is included as the injection device 9 is also possible. In addition, when the injection device 9 is configured to include both the direct injection fuel injection device 9a and the port injection fuel injection device 9b, the direct injection fuel injection device 9a may be disposed in either the main chamber 1 or the auxiliary chamber 11. In addition, in the above embodiment, a plug-in hybrid vehicle having at least three types of driving modes, namely, an electric driving mode, a series driving mode, and a parallel driving mode, is used as the vehicle 60, but the present invention can also be applied to other types of hybrid vehicles and general engine-equipped vehicles other than hybrid vehicles. [Explanation of symbols]

[0045] 1 Main room 2 Cylinder 3 Piston 4 Ignition device 9 Injection device 10 Engine 11 Antechamber 12 Communication path 20 Electronic Control Unit 30 First rotating electric machine 40 No. 2 rotating electric machine 50 Battery 60 Hybrid vehicle (vehicle) C. Combustion chamber

Claims

1. a combustion chamber including: a main chamber defined by an inner peripheral surface of a cylinder, an inner surface of a cylinder head, and a top surface of a piston; an auxiliary chamber defined at an end of the main chamber on the cylinder head side and separated from the main chamber by a partition; and a communication passage defined in the partition for communicating the main chamber with the auxiliary chamber; an injector for supplying fuel to the main chamber; an engine having an ignition device facing the pre-chamber and igniting the air-fuel mixture in the pre-chamber; A means for detecting or predicting the occurrence of knocking in the engine; A control means for performing control to avoid the knocking; Equipped with The fuel supplied to the main chamber is forced into the auxiliary chamber by the compression stroke, and the control means, when the occurrence of knocking is detected or predicted, performs fuel injection reduction control to reduce the amount of fuel injection of the auxiliary chamber injection that supplies fuel to the auxiliary chamber by the injection device, and performs ignition energy increase control to increase ignition energy to the mixture by the ignition device.

2. 2. The engine control device according to claim 1, wherein the control means performs ignition timing retard control for retarding an ignition timing of the ignition device to the air-fuel mixture when the occurrence of the knocking is detected or predicted.

3. 3. The engine control device according to claim 2, wherein the ignition energy increase control sets an increase amount of the ignition energy to be greater as an amount of retard of the ignition timing in the ignition timing retard control increases.

4. 4. The engine control device according to claim 2, wherein when the ignition timing retard control is performed, an injection timing retard control is performed to retard the injection timing of the pre-chamber injection by the injection device.

5. means for detecting torque fluctuations or combustion fluctuations in the engine; 5. The engine control device according to claim 1, wherein the ignition energy increase control is performed when the torque fluctuation or the combustion fluctuation exceeds a predetermined value.

6. an air-fuel ratio detection means for detecting or estimating an air-fuel ratio in the main chamber; 5. The engine control device according to claim 2, wherein, when the occurrence of knocking is detected or predicted, if the air-fuel ratio is richer than a predetermined value, the control means performs the ignition timing retard control and does not perform the ignition energy increase control, but reduces the fuel injection amount of main chamber injection that supplies fuel from the injection device to the main chamber, and if the detection or prediction of the occurrence of knocking continues, further performs the ignition timing retard control and performs the ignition energy increase control.

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