JP2011122544A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately restrain knocking while restraining degradation of thermal efficiency in an internal combustion engine equipped with a fuel supply device making the octane number of supplied fuel variable. <P>SOLUTION: The internal combustion engine includes an EGR control means for carrying out EGR control for restraining knocking when knocking is detected; a fuel supply control means for carrying out fuel supply control for restraining knocking when knocking is detected, and an ignition timing control means for carrying out ignition timing control for restraining knocking when knocking is detected. The ignition timing control for restraining knocking can be carried out after carrying out EGR control for restraining knocking and the fuel supply control for restraining knocking. For instance, the EGR control means drops the temperature of EGR gas to restrain knocking, and the fuel supply control means increases the octane number of supplied fuel to restrain knocking. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an internal combustion engine provided with a fuel supply device that can vary the octane number of supplied fuel.

  Patent Document 1 discloses a spark ignition type internal combustion engine that generates a high octane fuel and a low octane fuel from fuel in a gasoline tank and determines a mixing ratio of both fuels according to a load.

JP 2001-050070 A

  It is generally known that by reducing the octane number of the supplied fuel, it is possible to improve thermal efficiency, that is, improve fuel efficiency.

  On the other hand, in the spark ignition type internal combustion engine, conventionally, the ignition timing is retarded so as to suppress knocking. Such retarding of the ignition timing is effective for suppressing knocking, but generally deteriorates thermal efficiency. The deterioration in thermal efficiency due to the retarded ignition timing may exceed the improvement in thermal efficiency due to the use of a fuel having a low octane number.

  Accordingly, the present invention has been made in view of such a point, and an object of the present invention is to knock in an internal combustion engine including a fuel supply device that can change the octane number of fuel to be supplied while suppressing deterioration in thermal efficiency. It is to suppress appropriately.

  An internal combustion engine according to the present invention is a knocking detection means for detecting knocking, and an EGR control means capable of controlling supply and temperature of EGR gas, and when knocking is detected by the knocking detection means, EGR control means for executing EGR control; fuel supply control means for controlling the octane number of fuel; fuel supply control means for executing fuel supply control for suppressing knocking when knocking is detected by the knocking detection means; Ignition timing control means for controlling the ignition timing, and when knocking is detected by the knocking detection means, ignition timing control means for executing knocking suppression ignition timing control, and the knocking suppression ignition timing control is The EGR control for knocking suppression and the fuel supply control for knocking suppression are executed. After, characterized in that it is executed.

  Preferably, after the EGR control means performs control to lower the temperature of the EGR gas as knocking suppression EGR control, the fuel supply control means performs control to increase the octane number of the fuel supplied as knocking suppression fuel supply control. Good.

  Furthermore, after the knocking suppression fuel supply control is performed, the EGR control means may perform control to reduce the supply amount of EGR gas as knocking suppression EGR control.

  The fuel supply control means is a fuel supply apparatus capable of supplying a mixed fuel of a first fuel and a second fuel having an octane number lower than that of the first fuel, and a first fuel supply ratio relative to a total fuel supply amount of the mixed fuel. And the second fuel supply ratio can be controlled, and the fuel supply control means controls the fuel supply control for knocking suppression so that the first fuel supply ratio with respect to the total amount of fuel supply becomes high when knocking is detected by the knocking detection means. It is good to execute.

1 is a schematic configuration diagram showing an internal combustion engine to which an embodiment according to the present invention is applied. 2 is mapped data for fuel supply control of the internal combustion engine of FIG. 1. FIG. 2 is mapped data for EGR control of the internal combustion engine of FIG. 1. FIG. 2 is a flowchart for illustrating knocking suppression control of the internal combustion engine of FIG. 1.

  The internal combustion engine according to the present invention includes various means (various devices) that execute knocking suppression control so as to suppress knocking. As generally known, in order to suppress (avoid) knocking, it is effective to retard the ignition timing. However, the retardation of the ignition timing deteriorates the thermal efficiency of the internal combustion engine. Therefore, when suppressing knocking, it is desired not to deteriorate the thermal efficiency of the internal combustion engine. Therefore, in the present invention, when knocking occurs, first, knocking suppression EGR control and / or knocking suppression fuel supply control is performed before knocking suppression ignition timing control is performed in order to suppress knocking.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing an internal combustion engine 10 to which an embodiment according to the present invention is applied. The internal combustion engine 10 shown in FIG. 1 generates power by burning a mixture of fuel and air in a combustion chamber 14 formed in a cylinder block 12 and reciprocating a piston 18 in the cylinder 16. The internal combustion engine 10 is a 4-cycle engine (4-stroke engine).

  An intake port facing each combustion chamber 14 is opened and closed by an intake valve Vi and connected to the intake manifold 20. A surge tank 22 and an intake pipe 24 are sequentially connected to the upstream side of the intake manifold 20. The intake pipe 24 is connected to an air intake (not shown) via an air cleaner 26. A throttle valve 28 (here, an electronically controlled throttle valve driven by an actuator (not shown)) is incorporated in the middle of the intake pipe 24 (between the surge tank 22 and the air cleaner 26). For example, each of the intake port, the intake manifold 20, the surge tank 22, and the intake pipe 24 defines a part of the intake passage 30.

  On the other hand, an exhaust port facing each combustion chamber 14 is opened and closed by an exhaust valve Ve and connected to an exhaust manifold 32, and an exhaust pipe 34 is connected to the exhaust manifold 32 on the downstream side. Connected to the exhaust pipe 34 are a front-stage catalyst device 36 including a three-way catalyst and a rear-stage catalyst device 38 including a NOx storage reduction catalyst. The catalyst device is not limited to such a configuration. For example, the post-catalyst device 38 can include a three-way catalyst instead of the NOx storage reduction catalyst. For example, each of the exhaust port, the exhaust manifold 32 and the exhaust pipe 34 defines a part of the exhaust passage 40.

  The internal combustion engine 10 is provided with an exhaust gas recirculation (EGR) device (external EGR device) 42 that guides part of the exhaust gas flowing through the exhaust passage 40 to the intake passage 30. The external EGR device 42 includes an EGR passage 46 defined by an EGR pipe 44 so as to guide a part of the exhaust gas flowing through the exhaust passage 40 to the intake passage 30, and two EGR valves provided in the EGR passage 46, that is, first EGR valves. A 1EGR valve 48 and a second EGR valve 50 are provided. An EGR cooler 52 for cooling the recirculated exhaust gas (external EGR gas) is provided in the first EGR branch passage 46 a of the EGR passage 46. Here, each of the first EGR valve 48 and the second EGR valve 50 is configured as an electronically controlled EGR valve driven by an actuator (not shown). Both EGR valves 48 and 50 supply the amount of external EGR gas through the first EGR branch passage 46a in the EGR passage 46 and the amount of EGR gas through the second EGR branch passage 46b in the EGR passage 46. It is controlled to adjust the supply amount. As described above, since the EGR cooler 52 is provided in the first EGR branch passage 46a, the temperature of the EGR gas by the external EGR device 42 is controlled by controlling the supply amount of both the EGR branch passages 46a and 46b. can do. The first EGR valve 48 and the second EGR valve 50 may each be a three-way valve, and one of them may be omitted.

  The intake valve Vi and the exhaust valve Ve are opened and closed by a valve operating mechanism having a variable valve timing and / or a variable lift function, respectively. The valve operating mechanism including the drive mechanism 54 for the intake valve Vi and the drive mechanism 56 for the exhaust valve Ve synchronizes the intake valve Vi and the exhaust valve Ve with the rotation of the crankshaft to which the piston 18 is connected via a connecting rod. Thus, the mechanism can be individually controlled at an arbitrary opening degree and timing. Specifically, the drive mechanism 54 for the intake valve Vi and the drive mechanism 56 for the exhaust valve Ve each include a solenoid provided individually. That is, the intake valve Vi and the exhaust valve Ve are respectively electromagnetically driven valves. Note that the intake valve Vi and the exhaust valve Ve can realize a valve overlap that opens simultaneously and a negative valve overlap that closes them simultaneously. Since such valve operating mechanisms 54 and 56 are provided, it is possible to generate (supply) desired internal EGR gas. That is, the intake valve Vi, the exhaust valve Ve, and the valve mechanisms 54 and 56 constitute an internal EGR device for supplying internal EGR gas. The internal EGR device and the external EGR device 42 are collectively referred to as an EGR device in this specification.

  However, instead of such a configuration, the valve timing and cam profile can be set arbitrarily by switching, for example, a plurality of types of cams applied to a single valve as a valve operating mechanism of the intake valve Vi and the exhaust valve Ve. It is also possible to use a variable valve timing mechanism (VVT) that can be changed to Such a variable valve mechanism may be provided only for one of the intake valve Vi and the exhaust valve Ve.

  Further, each cylinder 16 of the internal combustion engine 10 has a spark plug 58. The spark plug 58 is disposed on the cylinder head so as to face the corresponding combustion chamber 14.

  Further, the internal combustion engine 10 has an injector 60 as shown in FIG. The injector 60 is provided for port injection. The injector 60 may be an in-cylinder injector.

  Here, the fuel supply device 62 including the injector 60 will be described. The fuel supply device 62 includes a main fuel tank 64, a separator 66, a first sub tank 68, a second sub tank 70, a first pump 72, a second pump 74, a control valve 76, and the injector 60. Is provided. These are connected by a passage formed by various pipes, but may be directly connected. The main fuel tank 64 is filled with gasoline. Here, two types of fuel are produced from the gasoline in the main fuel tank 64. The two types of fuels are a first fuel having an octane number equal to or higher than a predetermined octane number and a second fuel having a relatively lower octane number than the first fuel. The octane number of the first fuel is 100, for example, and the octane number of the second fuel is 88, for example. These two types of fuel are separated and generated by the separator 66. The control valve 76 is a three-way valve here, but may be various valves.

  In the present embodiment, the separator 66 includes a pervaporation membrane. Preferably, the pervaporation membrane is a polymer membrane. The fuel supplied from the main fuel tank 64 is separated into a first fuel that is a high-octane fuel and a second fuel that is a low-octane fuel by a pervaporation membrane. The generated first fuel is sent to the first sub tank 68, and the generated second fuel is sent to the second sub tank 70. The fuel in the main fuel tank 64 is supplied to the separator 66, the first fuel generated by the separator 66 is supplied to the first sub tank 68, and the second fuel generated by the separator 66 is supplied to the second sub tank 70. For each supply, various supply means, specifically a pump (not shown) are provided. The separator 66 can also include one or more means or members for controlling the amount and temperature of fuel supplied toward the pervaporation membrane.

  The supply amount of the first fuel in the first sub tank 68 and the supply amount of the second fuel in the second sub tank 70 are controlled by operation of the pumps 72 and 74 and the control valve 76. Thereby, in the fuel injected from the injector 60 (the mixed fuel of the first fuel and the second fuel), the first fuel supply ratio (first fuel supply ratio) and the second fuel supply ratio with respect to the total fuel supply amount (Second fuel supply ratio) can be adjusted. Thus, in the fuel supply device 62 of the present embodiment, the octane number of the supplied fuel can be made variable.

  Note that the configuration of the fuel supply apparatus is not limited to such a configuration, and may be various other configurations. For example, the number of pumps, installation positions, configurations and types, the number of valves, installation positions, configurations and types in the fuel supply device can be variously changed. Further, for example, the separator 66 converts the gasoline into a high-octane fuel having a high boiling point and a high octane number, that is, a first fuel, and a low-octane fuel having a low boiling point and a low octane number, that is, a second fuel. It may be a fractionator to be separated. In addition, instead of having a configuration for generating the first fuel and the second fuel from gasoline, the fuel supply device is provided so that the first fuel and the second fuel can be separately supplied from the outside in a replenishable manner. May be configured. Further, the present invention is not limited to the fuel supply device as described above, in which the octane number of the mixed fuel to be supplied is changed by generating the first fuel and the second fuel and changing their mixing ratio. Other fuel supply devices that directly obtain octane fuel can also be employed.

  The above-described throttle valve 28, EGR valves 48, 50, each drive mechanism 54, 56 included in the valve mechanism, each spark plug 58, each injector 60, separator 66, pumps 72, 74, control valve 76, etc. It is electrically connected to an ECU 80 that substantially functions as a control device for the engine 10. The ECU 80 includes a CPU, a ROM, a RAM, an input / output port, etc., all not shown. Various sensors are electrically connected to the ECU 80 via an A / D converter or the like, for example, an air flow meter 82 for detecting an intake air amount. The ECU 80 uses the various maps stored in a storage device such as a ROM and the throttle valve 28 and the EGR valve 48 so that a desired output can be obtained based on detection values obtained using various sensors. , 50, each drive mechanism 54, 56, each spark plug 58, each injector 60, and the like.

As shown in FIG. 1, the sensors connected to the ECU 80 include a crank position sensor 84. The crank position sensor 84 is a magnetic sensor or a photoelectric sensor including a rotor plate (signal plate) fixed to the crankshaft and the like, and provides a pulse signal indicating the rotation angle of the crankshaft to the ECU 80 every minute time. In the present embodiment, the crank position sensor 84 is also used as a rotational speed sensor for detecting the rotational speed of the internal combustion engine 10. Further, a throttle opening sensor 86 for detecting the opening of the throttle valve 28 (throttle opening) is provided. Further, an intake pressure sensor 88 is provided to detect the pressure in the intake passage 30, that is, the intake pressure. Further, a knock sensor 90 for detecting the occurrence of knocking in the internal combustion engine 10, an EGR cooler water temperature sensor 92 for detecting the temperature of the cooling water in the EGR cooler 52, and the temperature of the cooling water in the internal combustion engine 10 are detected. There are provided a water temperature sensor (not shown) and an accelerator opening sensor 94 for detecting the opening of the accelerator pedal. A vehicle speed sensor (not shown) for detecting the speed (vehicle speed) of the vehicle on which the internal combustion engine 10 is mounted is also provided. Further, an air-fuel ratio sensor (A / F sensor) 96 is provided in the exhaust passage 40. The A / F sensor 96 outputs an electrical signal corresponding to the air-fuel ratio in the exhaust gas in the exhaust passage to the ECU 80. The A / F sensor 96 may be an O ₂ sensor. Further, an O ₂ sensor 98 is provided in the exhaust passage 40. The O ₂ sensor 98 outputs an electrical signal corresponding to the oxygen concentration in the exhaust gas to the ECU 80.

  The ROM of the ECU 80 includes a routine for fuel supply control, a routine for ignition timing control, a routine for determining opening and closing timings of the intake valve Vi and the exhaust valve Ve and controlling them, an EGR gas supply routine, a throttle valve Data such as control routines, knocking suppression routines, maps used for them, and the like are stored. The ECU 80 executes fuel supply control, ignition timing control, EGR control, and the like according to application programs such as these various routines stored in the ROM or the like.

  That is, here, the EGR control means includes a part of the ECU 80. The fuel supply control means includes a part of the ECU 80. The ignition timing control means includes a part of the ECU 80. The knocking detection means includes a part of the ECU 80 and a knock sensor 90.

  Here, fuel supply control in the internal combustion engine 10 will be described. The ECU 80 controls the fuel injection supply from the injector 60 based on the mapped data in FIG. FIG. 2 shows the target octane number of the fuel supplied from the injector 60 with the rotation speed on the horizontal axis and the load on the vertical axis. The area A1 in FIG. 2 is an area for injecting and supplying only the second fuel that is a low octane fuel, and the area A2 in FIG. 2 is a fuel that includes the first fuel that is a high octane fuel (including a fuel composed only of the first fuel) ). In short, the fuel supply control is executed so that the octane number of the fuel injected and supplied from the injector 60 becomes higher as the operating state changes so as to belong to the high load operating region. In addition, the dotted line in FIG. 2 represents the full load.

  The EGR control in the internal combustion engine 10 will be described. The ECU 80 controls the supply of EGR gas based on the mapped data in FIG. FIG. 3 shows an EGR gas supply method selected in accordance with the operation state at this time, with the rotation speed on the horizontal axis and the load on the vertical axis. The B1 region in FIG. 3 is an internal EGR gas supply region, the B2 region is an external EGR gas supply region supplied via the second EGR branch passage 46b, and the B3 region is supplied via the first EGR branch passage 46a. The region where the external EGR gas is supplied and the region B4 is a region where the EGR gas is not supplied. In short, the EGR control is performed so that the cooling effect by the EGR control on the air-fuel mixture in the combustion chamber 14 increases as the operation state changes to belong to the operation region on the upper right side (high load high rotation side) in FIG. Executed. In addition, the dotted line in FIG. 3 represents the full load.

  When knocking is detected in the internal combustion engine 10 as described above, knocking suppression control is executed. In this knocking suppression control, the desired EGR gas is first supplied to the internal combustion engine when knocking occurs, and then the octane number of the fuel to be injected is increased, and then the EGR gas is increased. Is reduced, and finally the ignition timing is retarded. In such a series of knocking suppression controls, when knocking is avoided, the knocking suppression control is terminated, and the normal operation state is restored by a method suitable for smooth operation of the internal combustion engine 10. Is done. However, when the knocking suppression control is executed and the knocking is suppressed, the control data (for example, data in FIGS. 2 and 3) of the internal combustion engine 10 is corrected (learned) based on the execution data. . The corrected data and the like are continuously maintained and used until the internal combustion engine 10 is started and then stopped. When the internal combustion engine 10 is newly started, the internal combustion engine control is executed using the original data without correction. The present invention does not exclude that the data updated by the correction is used even after the next startup of the internal combustion engine 10.

  Hereinafter, the knocking suppression control of the internal combustion engine 10 of the present embodiment will be described based on the flowchart of FIG. In the flowchart of FIG. 4, a flow from when knocking begins to occur until knocking is suppressed (avoided) is schematically represented.

  When knocking is detected when the internal combustion engine 10 is in an operating state (positive determination in step S401), knocking suppression control is started so that knocking is suppressed. Whether knocking has occurred or not is determined based on an output signal from knock sensor 90.

  When knocking is detected, it is first determined whether or not external EGR is being supplied (step S403). Then, when the external EGR gas is not supplied via the external EGR device 42 (No in step 403), the supply of EGR gas is executed (started) (step S405). Whether or not the external EGR gas is supplied is determined based on the current operating state determined based on the rotation speed of the internal combustion engine 10 and the load (for example, accelerator opening) of the internal combustion engine 10 in any region of the map of FIG. Can be performed based on checking whether it belongs to.

  The supply of the EGR gas is first performed by supplying the internal EGR gas for a predetermined first time, and then performed by supplying the external EGR gas after the predetermined first time has elapsed. When the supply of the external EGR gas is executed, the supply of the internal EGR gas is stopped here, but the supply of the internal EGR gas may be continued. In addition, when supplying EGR gas here, that is, when it is determined that external EGR is not supplied and when EGR gas is supplied (when starting), no internal EGR gas is supplied. You don't have to. Note that controlling the supply of the EGR gas so as to change from the supply of the internal EGR gas to the supply of the external EGR gas corresponds to lowering the temperature of the supplied EGR gas.

  When knocking is still detected after the predetermined second time (time longer than the predetermined first time) has elapsed after the supply of EGR gas is started (positive determination in step S407), for further knock suppression Control is executed. Even when the external EGR gas has already been supplied (positive determination in step S403), further knocking suppression control is performed here.

  In order to perform further knocking suppression control, it is determined whether or not the external EGR gas (cooling EGR gas) that has passed through the EGR cooler 52 is supplied (step S409). This determination may be performed based on examining which region of the map in FIG. 3 the current operating state belongs to, or may be performed based on control data to the EGR valves 48, 50, or the like.

  When the EGR gas that has passed through the EGR cooler 52 is not supplied (No in step S409), the EGR valves 48 and 50 are controlled so that the EGR gas is supplied through the first EGR branch passage 46a (step S409). S411). When knocking is still detected (positive determination in step S413) even after the predetermined third time has elapsed after the supply of EGR gas via the EGR cooler 52 is started, further knocking suppression control is executed. Note that when the external EGR gas from which the EGR cooler 52 is obtained has already been supplied (positive determination in step S409), further knocking suppression control is performed here.

  In order to perform further knocking suppression control, it is determined whether or not the octane number of the supplied fuel is the maximum high octane number (step S415). This determination may be executed based on examining which region of the map in FIG. 2 the current operating state belongs to, or may be executed based on control data to the control valve 76 or the like. The maximum high octane number is the octane number of the first fuel that is the highest octane fuel among the various fuels that can be supplied by the fuel supply device 62. Here, the maximum high octane number can be determined by the performance of the fuel supply device 62. However, the maximum high octane number is not limited to such a value and can be set to various values.

  When the octane number of the supplied fuel is not the maximum high octane number (No in step S415), specifically, the total fuel supply amount of the mixed fuel of the first fuel and the second fuel so as to increase the octane number of the supplied fuel. The control valve 76 and the like are controlled so as to increase the first fuel supply ratio to (step S417). Such control for increasing the octane number of the fuel is executed continuously or stepwise at predetermined time intervals. Such control for increasing the octane number of the fuel is continued as long as knocking is detected (positive determination in step S419).

  When knocking is still detected (positive determination in step S419) and the octane number of the supplied fuel reaches the maximum high octane number (positive determination in step S415), further knocking suppression control is executed. Even when the octane number of the fuel supplied from the beginning has reached the maximum high octane number (positive determination in step S415), further knocking suppression control is performed here.

  In this case, the knocking suppression control is a control that further reduces the temperature in the combustion chamber 14 by reducing the supply amount of the EGR gas. Therefore, it is determined whether or not EGR gas is supplied (step S421).

  When the EGR gas is supplied (No in step S421), the EGR valves 48 and 50 are controlled so as to reduce the supply amount of the EGR gas (step S423). Such EGR gas reduction control is executed continuously or stepwise at predetermined time intervals. Such EGR gas reduction control is continued as long as knocking is detected (positive determination in step S425).

  When knocking is still detected (positive determination in step S425) and the supply of EGR gas is stopped (the supply amount of EGR gas becomes zero) (positive determination in step S421), further knocking suppression control is performed. Executed.

  As further knocking suppression control, control for retarding the ignition timing is executed (step S427). The ignition timing retarding control can be executed as generally known. The ignition timing retarding control is gradually executed (repeatedly executed) while knocking is detected (positive determination in step S429).

  When knocking is not detected or no longer detected (negative determination in steps S401, S407, S413, S419, S425, or S429), the knocking suppression control ends at that point.

  As described above, in the knocking suppression control, when knocking occurs, first, the temperature of the EGR gas is decreased (starting supply of EGR gas if EGR gas is not supplied) in order to suppress knocking. Thus, the EGR gas supply is controlled (EGR control for knocking suppression). When knocking still occurs, fuel supply is controlled so as to increase the octane number of the fuel in order to suppress knocking (fuel supply control for knocking suppression). Furthermore, when knocking still occurs, the supply of EGR gas is controlled to reduce the temperature by further reducing the supply of EGR gas in order to suppress knocking (knocking suppression EGR control). When knocking still occurs due to these, ignition timing retarding control is performed so as to retard the ignition timing (ignition timing control for knocking suppression).

  Thus, in the knocking suppression control, it is possible to avoid the ignition timing retarding control as much as possible. Therefore, knocking can be appropriately avoided while suppressing deterioration in thermal efficiency.

  In the EGR control for knocking suppression of the above embodiment, the EGR gas to be supplied is changed in the order of the supply of the internal EGR gas, the supply of the external EGR gas without passing through the EGR cooler 52, and the supply of the external EGR gas through the EGR cooler 52. Then, the temperature of the EGR gas was lowered. However, instead of using these three types of EGR gas, only two of these types of EGR gas may be used. Moreover, the temperature of EGR gas may be lowered | hung by changing the mixing ratio of these three types of EGR gases, or the mixing ratio of arbitrary two types of EGR gases among these three types of EGR gases.

  Moreover, in the said embodiment, in order to suppress knocking, after lowering | hanging the temperature of EGR gas, control which raises the octane number of a fuel was performed. Although this order is preferred, the present invention does not exclude that these orders are reversed. That is, in order to suppress knocking, it is also possible to perform control to lower the temperature of the EGR gas after increasing the octane number of the fuel.

  In addition, although the present invention has been described with a certain degree of specificity in the above-described embodiments and modifications thereof, the present invention is not limited to these, and the spirit and scope of the invention described in the scope of the claims. It should be understood that various modifications and changes can be made without leaving. That is, the present invention includes modifications and changes that fall within the scope and spirit of the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 14 Combustion chamber 28 Throttle valve 42 External EGR device 48 1st EGR valve 50 2nd EGR valve 52 EGR cooler 60 Injector 62 Fuel supply device 54, 56 Drive mechanism 90 Knock sensor Vi Intake valve Ve Exhaust valve

Claims (4)

Knocking detection means for detecting knocking;
EGR control means capable of controlling supply and temperature of EGR gas, and when knocking is detected by the knocking detection means, EGR control means for executing knocking suppression EGR control;
Fuel supply control means capable of controlling the octane number of the fuel, wherein when knocking is detected by the knocking detection means, fuel supply control means that executes fuel supply control for knocking suppression;
Ignition timing control means for controlling the ignition timing, and when knocking is detected by the knocking detection means, ignition timing control means for executing ignition timing control for knocking suppression;
With
The knocking suppression ignition timing control is executed after the knocking suppression EGR control and the knocking suppression fuel supply control are executed.   After the EGR control means performs control to lower the temperature of EGR gas as the knocking suppression EGR control, the fuel supply control means performs control to increase the octane number of the fuel supplied as the knocking suppression fuel supply control The internal combustion engine according to claim 1.   3. The internal combustion engine according to claim 2, wherein after the knocking suppression fuel supply control is performed, the EGR control unit performs control to reduce the supply amount of EGR gas as the knocking suppression EGR control. In the fuel supply apparatus capable of supplying a mixed fuel of a first fuel and a second fuel having an octane number lower than that of the first fuel, the fuel supply control means includes a first fuel supply ratio relative to a total fuel supply amount of the mixed fuel; The second fuel supply rate can be controlled,
The fuel supply control means, when knocking is detected by the knocking detection means,
The internal combustion engine according to any one of claims 1 to 3, wherein the knocking suppression fuel supply control is executed so that the first fuel supply ratio with respect to the total fuel supply amount is high.

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