JP2011112115A - Control device for spark ignition type engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively suppress abnormal combustion without having influences particularly to engine performance. <P>SOLUTION: This control device for a spark ignition type engine includes an abnormal combustion detecting means 72 detecting such abnormal combustion that mixture self-ignites more quickly than at a normal spark-ignition combustion starting time, and an abnormal combustion suppressing means 73 for executing predetermined control to suppress the occurrence of abnormal combustion when the detecting means 72 detects the abnormal combustion. The abnormal combustion suppressing means 73 performs control of the power transmission elements of automatic transmissions (30, 130) connected to the engine, as the predetermined control, to increase an engine revolving speed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides an abnormal combustion detecting means for detecting an abnormal combustion in which an air-fuel mixture self-ignites before a normal combustion start timing by spark ignition, and an abnormal combustion is generated when the abnormal combustion is detected by the detecting means. The present invention relates to a control device for a spark ignition engine provided with abnormal combustion suppressing means for executing predetermined control for suppressing the combustion.

  Conventionally, as shown in Patent Document 1 below, when the engine is in a state of rapid acceleration, it is determined whether or not an abnormal combustion occurrence condition is satisfied from each detected value such as intake pressure and rotational speed, When the generation condition is satisfied, the closing timing of the intake valve is changed to the retard side (retarded), and the compression start time is delayed to reduce the in-cylinder pressure, thereby preventing abnormal combustion. Has been done.

JP-A-11-324775

  When the closing timing of the intake valve is retarded under a predetermined condition as in Patent Document 1, although the in-cylinder pressure is reduced and abnormal combustion is suppressed, a substantial engine compression ratio ( When the effective compression ratio is reduced, there is a problem that the output torque of the engine is reduced.

  The control for suppressing the occurrence of abnormal combustion is not limited to the control for retarding the closing timing of the intake valve as described above. For example, the control for making the air-fuel ratio of the air-fuel mixture richer than the stoichiometric air-fuel ratio. You may go. If the fuel injection amount is increased by enriching the air-fuel ratio, the in-cylinder temperature decreases, so that abnormal combustion can also be suppressed. Furthermore, when the engine is a direct injection engine, abnormal combustion can be suppressed even if the fuel injection timing is retarded by, for example, injecting at least a part of the fuel during the compression stroke.

  However, enrichment of the air-fuel ratio leads to deterioration of fuel consumption performance, and retarding the injection timing may lead to deterioration of emissions such as smoke.

  The present invention has been made in view of the circumstances as described above, and provides a control device for a spark ignition engine capable of effectively suppressing abnormal combustion without particularly affecting engine performance. With the goal.

  In order to solve the above problems, the present invention provides an abnormal combustion detecting means for detecting abnormal combustion in which the air-fuel mixture self-ignites before the normal combustion start timing by spark ignition, and abnormal combustion is detected by the detecting means. A spark ignition type engine control device comprising: an abnormal combustion suppression means that executes predetermined control for suppressing occurrence of abnormal combustion when detected, wherein the predetermined control by the abnormal combustion suppression means The engine speed is increased by controlling the power transmission element of the automatic transmission connected to the engine (claim 1).

  In the above configuration, the “power transmission element of the automatic transmission” is a part necessary for transmitting the driving force of the engine among the parts provided in the automatic transmission, and operates the part. This means that the engine speed can be increased.

  According to the present invention, when abnormal combustion (pre-ignition) due to self-ignition is detected, the frictional engagement element of the automatic transmission is slid to increase the engine speed, so that the pre-ignition is likely to occur. Since the operation state is shifted from the region to the outside, for example, when preignition occurs, preignition is suppressed by retarding the closing timing of the intake valve or enriching the air-fuel ratio. Unlike the case, there is an advantage that the occurrence of pre-ignition can be effectively suppressed without particularly affecting the engine performance.

  Preferably, the predetermined control by the abnormal combustion control means is, for example, to increase the rotational speed of the engine by sliding a frictional engagement element of an automatic transmission (claim 2).

  According to this configuration, the engine speed can be easily and appropriately increased by sliding the frictional engagement element to reduce the load applied to the engine.

  When the automatic transmission is an automatic multi-stage transmission including a multi-stage transmission capable of forming a plurality of shift stages and a starter that transmits engine driving force to the transmission, the abnormal combustion control means Preferably, the predetermined control is to increase the rotational speed of the engine by sliding the friction engagement element of the multi-stage transmission.

  According to this configuration, by sliding the friction engagement element of the multi-stage transmission, the engine rotation speed can be increased with excellent responsiveness, and pre-ignition can be more quickly suppressed.

  The predetermined control by the abnormal combustion control means may increase the rotational speed of the engine by sliding the friction engagement element of the starting device (claim 4).

  According to this configuration, the engine speed is increased for a long time in order to suppress pre-ignition by sliding the frictional engagement element of the starting device that is relatively large, has a large heat capacity, and does not easily rise in temperature even when slip control is performed. Even if it is necessary to raise the temperature of the automatic transmission, there is no problem caused by excessive temperature rise, and there is an advantage that the reliability as a product of the automatic transmission can be sufficiently secured.

  As a more preferable aspect, when the abnormal combustion is detected by the abnormal combustion detecting means, the abnormal combustion control means first executes control to slide the friction engagement element of the multi-stage transmission, and then the friction engagement of the multi-stage transmission. When the temperature of the element becomes higher than a predetermined temperature, the control is switched to the control of sliding the frictional engagement element of the starting device (Claim 5).

  According to this configuration, it is possible to appropriately select the frictional engagement element to be slid based on the temperature of the frictional engagement element of the multi-stage transmission, and attach importance to control responsiveness that increases the engine rotation speed when pre-ignition occurs. However, there is an advantage that the reliability as a product of the automatic transmission can be sufficiently secured.

  When the automatic transmission is an automatic continuously variable transmission including a continuously variable transmission capable of changing the gear ratio steplessly, the predetermined control by the abnormal combustion control means is, for example, a shift of the continuously variable transmission. Preferably, the engine speed is increased by changing the ratio to the deceleration side.

  According to this configuration, there is an advantage that the occurrence of pre-ignition can be suppressed without particularly affecting the engine performance by changing the gear ratio steplessly and increasing the engine rotational speed by a necessary amount.

  The automatic continuously variable transmission transmits the driving force of the engine to the continuously variable transmission, the forward / reverse switching device connected to the continuously variable transmission as the device for switching between forward and reverse, and the forward / backward switching device. When the abnormal combustion is detected by the abnormal combustion detection means, the abnormal combustion control means first performs control to slide the friction engagement element of the forward / reverse switching device, and the forward / reverse switching is performed. When the frictional engagement element of the device becomes higher than a predetermined temperature, the control is switched to the control of sliding the frictional engagement element of the starter, and when the temperature of the frictional engagement element of the starter becomes higher than the predetermined temperature, the steplessly It is preferable to switch the control to change the speed ratio of the transmission to the deceleration side.

  According to this configuration, it is appropriate to determine which frictional engagement element should be slid or to change the gear ratio of the continuously variable transmission based on the temperature of each frictional engagement element of the starting device and the forward / reverse switching device. There is an advantage that the reliability as a product of the automatic transmission can be sufficiently secured while emphasizing the responsiveness of the control for increasing the engine rotation speed when pre-ignition occurs.

  As described above, according to the spark ignition engine control apparatus of the present invention, abnormal combustion can be effectively suppressed without particularly affecting engine performance.

It is a figure showing the whole spark ignition engine composition concerning a 1st embodiment of the present invention. It is sectional drawing which shows the structure of the engine main body in 1st Embodiment. 1 is a schematic diagram showing a configuration of an automatic multi-stage transmission according to a first embodiment. It is a fastening table | surface which shows the relationship between the state of a friction fastening element etc. of the automatic multistage transmission in 1st Embodiment, and a gear stage. It is a block diagram which shows the control system of the engine in 1st Embodiment. It is a figure for illustrating the range of the abnormal combustion danger area in the engine of a 1st embodiment. It is a flowchart which shows an example of the control action performed in the engine of 1st Embodiment. FIG. 8 is a subroutine (part 1) showing specific contents of pre-ignition suppression control executed in the flowchart of FIG. 7; FIG. It is a subroutine (the 2) which shows the specific content of the said preignition suppression control. It is a figure for demonstrating 2nd Embodiment of this invention, and is a skeleton diagram which shows the structure of an automatic continuously variable transmission. It is a fastening table | surface which shows the relationship between the state of the friction fastening element of the automatic continuously variable transmission in 2nd Embodiment, and the advancing direction of a vehicle. It is a block diagram which shows the control system of the engine in 2nd Embodiment. It is a subroutine which shows the specific content of the preignition suppression control performed in 2nd Embodiment.

<Embodiment 1>
(1-1) Overall Configuration of Engine FIG. 1 is a diagram showing the overall configuration of a spark ignition engine according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the configuration of the engine body 1. is there. The engine shown in these drawings is an in-line multi-cylinder engine in which a plurality (four in the illustrated example) of cylinders 2 are arranged in a row in the engine body 1 as a power source for driving a vehicle. It is arranged in the engine room outside the figure.

  A piston 3 (FIG. 2) is inserted into each cylinder 2 of the engine body 1 so as to be slidable back and forth. The piston 3 is connected to the crankshaft 4 via a connecting rod 5, and the crankshaft 4 rotates about the central axis in accordance with the reciprocating motion of the piston 3.

  A combustion chamber 6 is formed above the piston 3, an intake port 7 and an exhaust port 8 are opened in the combustion chamber 6, and an intake valve 9 and an exhaust valve 10 that open and close the ports 7 and 8 are the upper part of the engine body 1. Is provided. The illustrated engine is a so-called double overhead camshaft (DOHC) engine, and two intake valves 9 and two exhaust valves 10 are provided for each cylinder 2. A valve operating mechanism (not shown) including a pair of camshafts rotating in conjunction with the crankshaft 4 is provided above the intake valve 9 and the exhaust valve 10. , 10 are individually driven to open and close.

  The valve operating mechanism for the intake valve 9 is provided with a VVT 12 as a variable valve timing mechanism that makes it possible to change the operation timing of the intake valve 9.

  Various types of valve timing variable mechanisms have been put into practical use and are known. For example, a hydraulic variable mechanism can be used as the VVT 12. In the hydraulic variable mechanism, a plurality of liquid chambers arranged in the circumferential direction are provided between a camshaft for the intake valve 9 and a driven shaft (not shown) arranged coaxially therewith. By forming a pressure difference between the liquid chambers, a predetermined phase difference is formed between the camshaft and the driven shaft. The phase difference is variably set within a predetermined angle range, so that the operation timing of the intake valve 9 is continuously changed.

  As shown in FIGS. 1 and 2, the engine body 1 includes an injector 15 that directly injects fuel into the combustion chamber 6 and an ignition plug 16 that discharges an ignition spark into the combustion chamber 6. One for each. In the illustrated example, an ignition plug 16 is provided near the top of the combustion chamber 6, and an injector 15 is provided on the side of the intake side of the combustion chamber 6. The injector 15 is disposed slightly obliquely downward so that fuel can be injected toward the vicinity of the electrode of the spark plug 16.

  As shown in FIG. 2, the engine body 1 includes an engine rotation speed sensor 51 that detects the rotation speed of the crankshaft 4, a water temperature sensor 52 that detects the temperature of cooling water of the engine, and vibration caused by combustion. And a vibration sensor 53 for detecting the strength (vibration level).

  An intake passage 21 and an exhaust passage 22 are connected to the intake port 7 and the exhaust port 8 of the engine body 1, respectively.

  The intake passage 21 is a passage for supplying combustion air (fresh air) to the combustion chamber 6. As shown in FIG. 1, a plurality of branch passages provided independently for each cylinder 2. It has the part 21a and the common channel | path part 21b provided in the upstream in common. The common passage 21b includes a throttle valve 17 that adjusts the flow rate of intake air flowing into the engine body 1, an air flow sensor 54 that detects the flow rate of intake air, and an intake air temperature that detects the temperature of intake air (intake air temperature). A sensor 55 is provided.

  The throttle valve 17 is composed of, for example, an electronically controlled throttle valve, and is electrically opened and closed according to the degree of opening of an accelerator pedal (not shown) that is depressed by the driver. In other words, the accelerator pedal is provided with an accelerator opening sensor 56 (FIG. 5), and an electric power (not shown) is selected according to the accelerator pedal opening (accelerator opening) detected by the accelerator opening sensor 56. An actuator of the type is configured to open and close the throttle valve 17.

  The exhaust passage 22 is a passage for discharging burned gas (exhaust gas) generated in the combustion chamber 6. Like the intake passage 21, the exhaust passage 22 is a plurality of independently provided for each cylinder. A branch passage portion 22a and a common passage portion 22b provided in common on the downstream side thereof are provided.

(1-2) Configuration of Automatic Transmission The automatic multi-stage transmission 30 shown in FIG. 3 is connected to the engine configured as described above. The automatic multi-stage transmission 30 transmits the driving force (rotational force of the crankshaft 4) input from the engine to the drive shaft 45 of the vehicle while decelerating at a predetermined reduction ratio, and corresponds to the traveling state of the vehicle. A multi-stage transmission 32 that selectively forms a gear stage, and a torque converter 31 (corresponding to a starting device according to the present invention) that interlocks and connects the crankshaft 4 of the engine and the multi-stage transmission 32 are provided.

  The torque converter 31 is disposed between a pump impeller 34 that rotates integrally with the crankshaft 4 of the engine, a turbine runner 35 that is disposed so as to face the pump impeller 34, and the pump impeller 34 and the turbine runner 35. The driving force of the pump impeller 34 that has a stator (fixed blade) 36 and is rotationally driven by the engine is transmitted to the turbine runner 35 via hydraulic oil (ATF oil) filled in the torque converter 31. It has become so. The turbine runner 35 is connected to a turbine shaft 37 serving as an output shaft of the torque converter 31. When the turbine runner 35 is rotated by receiving the driving force of the pump impeller 34, the turbine shaft 35 is integrated with the turbine runner 35. 37 rotates.

  The torque converter 31 incorporates a lock-up clutch LC as a frictional engagement element that directly connects the turbine runner 35 and the crankshaft 4 of the engine, and the lock-up clutch LC is fastened as necessary. Thus, power is transmitted between the engine and the multi-stage transmission 32 without loss (without slippage due to fluid).

  The multi-stage transmission device 32 includes a first planetary gear mechanism 40 and a second planetary gear mechanism 41, and forward clutch C1, 3-4 clutch as means for switching a power transmission path via the gear mechanisms 40, 41. It has a frictional engagement element composed of C2, reverse clutch C3, low reverse brake B1, and 2-4 brake B2, and a one-way clutch C4. And it is comprised so that the some gear stage which consists of four forward speeds (1st-4th speed) and reverse speed according to the intermittent of these frictional engagement elements C1, C2, C3, B1, B2 etc. can be formed. Yes. The rotational force of the turbine shaft 37 of the torque converter 31 is transmitted to the output gear 43 after being decelerated at a speed ratio corresponding to each gear.

  The first planetary gear mechanism 40 includes a sun gear 40a, a ring gear 40d formed in a ring shape so as to surround the sun gear 40a, and a plurality of planetary gears 40b disposed in mesh between the sun gear 40a and the ring gear 40d. And a carrier 40c for holding the planetary gear 40b. Similarly, the second planetary gear mechanism 41 includes a sun gear 41a, a ring gear 41d formed in a ring shape so as to surround the sun gear 41a, and a plurality of gears arranged between the sun gear 41a and the ring gear 41d. It has a planetary gear 41b and a carrier 41c that holds the planetary gear 41b.

  The ring gear 40d of the first planetary gear mechanism 40 and the carrier 41c of the second planetary gear mechanism 41 are coupled, and the carrier 40c of the first planetary gear mechanism 40 and the ring gear 41d of the second planetary gear mechanism 41 are connected. By being connected, the planetary gear mechanisms 40 and 41 can be interlocked. An output gear 43 is integrally connected to the carrier 40 c of the first planetary gear mechanism 40.

  The forward clutch C1 connects the turbine shaft 37 of the torque converter 31 and the sun gear 40a of the first planetary gear mechanism 40 in an intermittent manner, and the 3-4 clutch C2 includes the turbine shaft 37 and the second planetary gear mechanism. The reverse clutch C3 connects the turbine shaft 37 and the sun gear 41a of the second planetary gear mechanism 41 in an intermittent manner.

  The low reverse brake B1 fixes or releases the ring gear 40d of the first planetary gear mechanism 40 and the carrier 41c of the second planetary gear mechanism 41 with respect to the transmission case 42, and the 2-4 brake B2 The sun gear 41 a of the planetary gear mechanism 41 is fixed to or released from the mission case 42.

  The one-way clutch C4 allows (unlocks) only the rotation of the ring gear 40d of the first planetary gear mechanism 40 and the carrier 41c of the second planetary gear mechanism 41 in one direction (the driving direction of the crankshaft 4), and reverses the direction. Rotation is restricted (locked).

  Then, power is transmitted between the turbine shaft 37 and the output gear 43 in accordance with the on / off state of the frictional engagement elements (clutch C1 to C3, brakes B1 and B2) and switching of the one-way clutch C4. The route is changed, and the gear position of the multi-stage transmission 32 is switched. The rotational force of the output gear 43 is transmitted to the left and right drive shafts 45 via the differential device 44.

  FIG. 4 is an engagement table showing the relationship between the friction engagement elements (clutch C1 to C3, brakes B1 and B2) and the one-way clutch C4, and the shift speed of the multi-stage transmission 32. The locked state indicates the state in which no mark is released or unlocked.

  According to the engagement table of FIG. 4, at the first speed, the forward clutch C1 is engaged and the one-way clutch C4 is locked, at the second speed, the forward clutch C1 and the 2-4 brake B2 are engaged, and at the third speed, the forward clutch C1 is forward. Clutch C1 and 3-4 clutch C2 are engaged, and at the fourth speed, 3-4 clutch C2 and 2-4 brake B2 are engaged. At reverse speed, reverse clutch C3 and low reverse brake B1 are engaged.

  Although details are omitted, the clutches C1 to C3 and the brakes B1 and B2 are driven by hydraulic pressure supplied from a hydraulic circuit (not shown). That is, the friction engagement elements (clutch C1 to C3, brakes B1 and B2) are engaged by changing the oil passage, hydraulic pressure, and the like according to the operation of a switching valve including a solenoid valve included in the hydraulic circuit. Alternatively, it is released and the gear position of the multi-stage transmission 32 is switched accordingly. The lockup clutch LC of the torque converter 31 is also driven by the hydraulic pressure supplied from the hydraulic circuit.

  In the automatic multi-stage transmission 30 configured as described above, the 1st to 4th speed or the reverse speed is determined based on the operating states (engaged or released) of the frictional engagement elements C1 to C3, B1 and B2 of the multistage transmission 32. A shift sensor 57 for detecting which gear stage is selected from among the speeds, first to fifth temperature sensors 58 to 62 for detecting temperatures of the respective frictional engagement elements C1 to C3, B1 and B2, and a torque converter A lockup sensor 63 that detects the presence or absence (ON / OFF) of lockup based on the operating state of the lockup clutch LC 31 and a sixth temperature sensor 64 that detects the temperature of the lockup clutch LC are provided. (See FIG. 5).

  When the correspondence between the first to fifth temperature sensors 59 to 62 and the frictional engagement elements C1 to C3, B1, and B2 is clearly shown, the first temperature sensor 58 determines the temperature of the forward clutch C1 and the second temperature sensor. 59 is the temperature of the 3-4 clutch C2, the third temperature sensor 60 is the temperature of the reverse clutch C3, the fourth temperature sensor 61 is the temperature of the low reverse brake B1, and the fifth temperature sensor 62 is the temperature of the 2-4 brake B2. Each temperature is detected.

  The automatic multi-stage transmission 30 is provided with a vehicle speed sensor 50 (FIG. 5) that detects the traveling speed (vehicle speed) of the host vehicle based on the rotational speed of the output shaft.

(1-3) Configuration of Control System FIG. 5 is a block diagram showing an engine control system. The ECU 70 shown in the figure is a control device for comprehensively controlling each part of the engine and the automatic multi-stage transmission 30, and includes a well-known CPU, ROM, RAM, and the like.

  Detection signals from various sensors are input to the ECU 70. That is, the ECU 70 includes the vehicle speed sensor 50, the engine rotation speed sensor 51, the water temperature sensor 52, the vibration sensor 53, the air flow sensor 54, the intake air temperature sensor 55, the accelerator opening sensor 56, the shift sensor 57, and the first to fifth temperature sensors. 58 to 62, a lockup sensor 63, and a sixth temperature sensor 64, which are electrically connected to the vehicle speed V, the engine rotational speed Ne, the engine water temperature Te, and the vibration level NK. , Intake air amount Qa, intake air temperature Ta, accelerator opening ACC, shift position of multi-stage transmission 32, forward clutch C1 temperature T1, 3-4 clutch C2 temperature T2, reverse clutch C3 temperature T3, low reverse brake B1 Temperature T4, 2-4 brake B2 temperature T5, torque converter 31 lock Whether-up, information such as the temperature T6 of the lock-up clutch LC is adapted to be sequentially inputted to the ECU 70.

  The ECU 70 also includes the VVT 12, the injector 15, the spark plug 16, the throttle valve 17, the lock-up clutch LC of the torque converter 31, and the friction engagement elements (clutch C1 to C3, brakes B1 and B2) of the multistage transmission 32. These devices are also electrically connected, and are configured to output drive control signals to these devices.

  A more specific function of the ECU 70 will be described. The ECU 70 includes an operation state determination unit 71, an abnormal combustion detection unit 72, and an abnormal combustion suppression unit 73 as main functional elements.

  The operating state determining means 71 specifies the operating state of the engine at each time point on the map shown in FIG. 6, and determines whether or not the position is within the abnormal combustion risk area PA in the drawing. is there. In the map of FIG. 6, the horizontal axis is the engine rotation speed Ne, and the vertical axis is the intake charge efficiency (engine load) CE, and the abnormal combustion risk area PA is set in the upper left part of the map. That is, in the abnormal combustion risk area PA located in the upper left part of the map, the load is relatively high and the rotational speed Ne is low, so that the combustion chamber 6 is likely to become high temperature, and the heat receiving period from the wall surface of the combustion chamber 6 is long. long. For this reason, in the abnormal combustion risk area PA, abnormal combustion called pre-ignition in which the air-fuel mixture self-ignites before the normal combustion start timing determined based on the timing of spark ignition by the spark plug 16 is higher than in other areas. It is easy to generate. Therefore, the operating state determination means 71 determines the risk of the pre-ignition by determining whether or not the engine operating state is within the abnormal combustion risk area PA.

  The abnormal combustion detection means 72 determines whether or not pre-ignition has actually occurred when the operation state determination means 71 confirms that the engine operating state is within the abnormal combustion risk area PA. The determination is based on 53 detection values. That is, when a pre-ignition occurs, a large vibration is generated in the engine at a specific time in the combustion cycle. Therefore, the abnormal combustion detection means 72 generates the pre-ignition based on the vibration level generated in the engine and the generation time. The presence or absence of is determined.

  The abnormal combustion suppressing means 73 executes predetermined control for suppressing abnormal combustion when it is confirmed by the abnormal combustion detecting means 72 that pre-ignition has occurred.

  Specifically, the abnormal combustion control means 73 is one of the friction engagement elements of the automatic multi-stage transmission 30, that is, the clutches C <b> 1 to C <b> 3 and the brake B <b> 1 of the multi-stage transmission 32 as control for suppressing abnormal combustion. Control for increasing the engine rotational speed Ne by intentionally sliding either B2 or the lockup clutch LC of the torque converter 31 is executed. Specifically, the control for sliding the frictional engagement elements (clutch C1 to C3, brakes B1 and B2, lockup clutch LC) is performed by adjusting the hydraulic pressure supplied to each element. That is, the hydraulic pressure supplied to the frictional engagement elements C1 to C3, B1, B2, and LC including the clutch and the brake according to the control of the switching valve of the hydraulic circuit is the hydraulic pressure necessary to maintain the engaged state. And the frictional engagement elements C1 to C3, B1, B2, and LC are intentionally slid. When any of the frictional engagement elements C1 to C3, B1, B2, and LC slips and a transmission loss of driving force occurs, the load applied to the engine decreases, so the engine rotational speed Ne increases accordingly, and the arrow in FIG. As indicated by R, as a result of the engine operating state shifting to a higher rotation side than the abnormal combustion risk area PA, the occurrence of pre-ignition is avoided.

  However, if the control for sliding any of the frictional engagement elements C1 to C3, B1, B2, and LC is performed without limitation, the temperature of the frictional engagement elements C1 to C3, B1, B2, and LC increases excessively, May cause problems such as burn-in. Therefore, when all the frictional engagement elements to be slid become high temperature, the abnormal combustion suppression means 73 is not a control for sliding any of the frictional engagement elements C1 to C3, B1, B2, and LC, By performing control to reduce the effective compression ratio of the engine, occurrence of pre-ignition is suppressed. Specifically, the effective compression ratio of the engine is lowered by operating the VVT 12 and changing (retarding) the closing timing of the intake valve 9 to the retard side.

  That is, the intake valve 9 is normally closed in the vicinity of the retarded side of the intake bottom dead center (timing slightly past the intake bottom dead center), but the closing timing of the intake valve 9 is reduced by intake V dead due to the operation of the VVT 12. If it is set much later than the point, the timing at which compression is substantially started is delayed, and the substantial compression ratio (effective compression ratio) of the engine is lowered accordingly. When the effective compression ratio decreases, the in-cylinder pressure near the compression top dead center decreases, so that a spontaneous chemical reaction is less likely to occur, and the occurrence of pre-ignition is suppressed.

  If the VVT 12 is a variable mechanism of a type that forms a predetermined phase difference between the camshaft and the driven shaft, not only the closing timing of the intake valve 9 depending on the operation of the VVT12. The opening timing of the exhaust valve 10 is also changed. Here, the opening timing of the exhaust valve 10 may be variable or constant, and at least the closing timing of the intake valve 9 is changed.

(1-4) Specific Example of Control Operation Next, a specific example of the control operation executed in the engine of the present embodiment configured as described above will be described based on the flowcharts shown in FIGS. First, when the processing shown in the flowchart of FIG. 7 is started, the ECU 70 executes control for reading various sensor values (step S1). Specifically, the vehicle speed sensor 50, the engine rotation speed sensor 51, the water temperature sensor 52, the vibration sensor 53, the air flow sensor 54, the intake air temperature sensor 55, the accelerator opening sensor 56, the shift sensor 57, and the first to fifth temperature sensors 58. To 62, the lockup sensor 63, and the sixth temperature sensor 64, as detected values of the sensors, the vehicle speed V, the engine rotational speed Ne, the engine water temperature Te, the vibration level NK, the intake air amount Qa, the intake air temperature Ta, the accelerator opening Degree ACC, the shift position of the multi-stage transmission 32, the temperature T1 of the forward clutch C1, the temperature T2 of the 3-4 clutch C2, the temperature T3 of the reverse clutch C3, the temperature T4 of the low reverse brake B1, and the temperature T5 of the 2-4 brake B2. , Whether the torque converter 31 is locked up, the temperature T6 of the lockup clutch LC, etc. Distribution is loaded.

  Next, the operating state determination means 71 of the ECU 70 determines that the current operating state of the engine is based on the engine rotational speed Ne, the intake air amount Qa, etc. read in step S1, and that the abnormal combustion risk shown in FIG. Control is performed to determine whether the area is within the area PA (step S2). For example, if the upper limit value of the horizontal axis (rotational speed) of the abnormal combustion risk area PA is the upper limit rotational speed Ne0 and the lower limit value of the vertical axis (intake charging efficiency) is the lower limit charging efficiency CE0, the current engine rotational speed Ne is When the intake charging efficiency CE obtained from the intake air amount Qa or the like is smaller than the upper limit rotational speed Ne0 and greater than the lower limit charging efficiency CE0, it is determined that the engine operating state is in the abnormal combustion risk area PA.

  If it is determined YES in step S2 and it is confirmed that the engine operating state is within the abnormal combustion risk area PA, that is, there is a risk of pre-ignition due to a relatively low rotational speed and high load. If it is confirmed, the abnormal combustion detection means 72 of the ECU 70 executes control for determining whether or not pre-ignition has occurred based on the vibration level NK read in step S1 (step S3). ). Specifically, when the vibration level NK detected by the vibration sensor 53 is larger than a predetermined threshold NK0 and the detection time is within a predetermined range during the compression stroke, that is, from the start of the compression stroke. It is determined that pre-ignition has occurred when NK> NK0 within the period up to the normal combustion start timing (slightly retarded from the ignition timing).

  When it is determined YES in step S3 and it is confirmed that pre-ignition has occurred, the abnormal combustion suppression means 73 of the ECU 70 intentionally increases the engine rotation speed Ne in order to suppress the pre-ignition. (Pre-ignition suppression control) is started (step S4), and thereafter, the abnormal combustion suppression flag F (its default value is 0) for indicating whether the control is being executed is being executed. The control for inputting “1” indicating “” is executed (step S5).

  Next, the contents of the pre-ignition suppression control in step S4 will be described with reference to the flowcharts of FIGS. When the process shown in this flowchart is started, the abnormal combustion suppression means 73 selects the reverse speed as the shift speed of the multi-stage transmission 32 based on the detection value of the shift sensor 57 read in step S1 of FIG. The control which determines whether it exists is performed (step S11). The frictional engagement elements that are engaged in the multi-stage transmission 32 at the reverse speed are the reverse clutch C3 and the low reverse brake B1, as shown in FIG.

  When it is determined YES in step S11 and it is confirmed that the reverse speed is selected, the abnormal combustion suppression means 73 determines that the temperature T3 of the reverse clutch C3 read in step S1 of FIG. Control for determining whether or not the threshold value is higher than the threshold value T3a is executed (step S12).

  When it is determined NO in step S12 and it is confirmed that the temperature T3 of the reverse clutch C3 is equal to or lower than the threshold value T3a, the abnormal combustion suppression means 73 slides the reverse clutch C3 to increase the engine rotational speed Ne. Control to be executed is executed (step S13). That is, by reducing the hydraulic pressure supplied to the reverse clutch C3 below the hydraulic pressure required for engagement and intentionally sliding the reverse clutch C3, the engine rotational speed Ne is abnormal as shown by the arrow R in FIG. The temperature is increased to a value higher than the upper limit rotational speed Ne0 of the combustion risk area PA, thereby avoiding the occurrence of pre-ignition.

  On the other hand, if it is determined as YES in step S12 and it is confirmed that the temperature T3 of the reverse clutch C3 is higher than the threshold value T3a, the abnormal combustion suppression means 73 reads the low reverse read in step S1 of FIG. Control is performed to determine whether or not the temperature T4 of the brake B1 is higher than a predetermined threshold value T4a (step S14).

  When it is determined NO in step S14 and it is confirmed that the temperature T4 of the low reverse brake B1 is equal to or lower than the threshold value T4a, the abnormal combustion suppression means 73 slides the low reverse brake B1 to rotate the engine. Control is executed to increase the speed Ne to a value on the higher rotation side than the abnormal combustion risk area PA (step S15).

  On the other hand, when it is determined YES in step S14 and it is confirmed that the temperature T4 of the low reverse brake B1 is higher than the threshold value T4a, the abnormal combustion suppression means 73 proceeds to step S28 in FIG. Control is performed to determine whether or not the torque converter 31 is in a lock-up state. That is, whether or not the torque converter 31 is in the lock-up state is determined by determining whether or not the lock-up clutch LC is engaged based on the detection value of the lock-up sensor 63 read in step S1 of FIG. judge.

  When it is determined YES in step S28 and it is confirmed that the lockup state is established, the abnormal combustion suppression means 73 determines that the temperature T6 of the lockup clutch LC read in step S1 of FIG. Control for determining whether or not the threshold value is higher than the threshold value T6a is executed (step S29).

  When it is determined NO in step S29 and it is confirmed that the temperature T6 of the lockup clutch LC is equal to or lower than the threshold value T6a, the abnormal combustion suppression means 73 causes the engine rotation by sliding the lockup clutch LC. Control is performed to increase the speed Ne to a value on the higher rotation side than the abnormal combustion risk area PA (step S30).

  On the other hand, if NO is determined in step S28 and it is confirmed that the lock-up state is not established, or YES is determined in step S29 and it is confirmed that the temperature T6 of the lock-up clutch LC is higher than the threshold value T6a. If it is, the abnormal combustion suppression means 73 performs control to operate the VVT 12 to retard the closing timing of the intake valve 9 (step S31). That is, by retarding the closing timing of the intake valve 9 and reducing the effective compression ratio of the engine, the in-cylinder pressure is reduced and the occurrence of pre-ignition is suppressed.

  Next, a description will be given of the control operation when NO is determined in step S11 of FIG. 8, that is, when a speed other than the reverse speed (1st to 4th) is selected as the speed of the multi-stage transmission 32. To do. In this case, the abnormal combustion suppressing means 73 executes control for determining whether or not the gear position of the multi-stage transmission 32 is the fourth speed (step S16). The frictional engagement elements that are engaged in the multi-stage transmission 32 at the fourth speed are the 3-4 clutch C2 and the 2-4 brake B2, as shown in FIG.

  When it is determined YES in step S16 and it is confirmed that the fourth speed is selected, the abnormal combustion suppression means 73 determines that the temperature T2 of the 3-4 clutch C2 read in step S1 of FIG. Control for determining whether or not the threshold value is higher than a predetermined threshold value T2a is executed (step S17).

  When it is determined NO in Step S17 and it is confirmed that the temperature T2 of the 3-4 clutch C2 is equal to or lower than the threshold value T2a, the abnormal combustion suppression means 73 slides the 3-4 clutch C2, Control for increasing the engine rotation speed Ne to a value on the higher rotation side than the abnormal combustion risk area PA is executed (step S18).

  On the other hand, when it is determined YES in step S17 and it is confirmed that the temperature T2 of the 3-4 clutch C2 is higher than the threshold value T2a, the abnormal combustion suppression means 73 is read in step S1 of FIG. Control is performed to determine whether or not the temperature T5 of the 2-4 brake B2 is higher than a predetermined threshold T5a (step S19).

  When it is determined NO in Step S19 and it is confirmed that the temperature T5 of the 2-4 brake B2 is equal to or lower than the threshold value T5a, the abnormal combustion suppression means 73 slides the 2-4 brake B2, Control for increasing the engine rotation speed Ne to a value on the higher rotation side than the abnormal combustion risk area PA is executed (step S20).

  On the other hand, when it is determined YES in step S19 and it is confirmed that the temperature T5 of the 2-4 brake B2 is higher than the threshold value T5a, the abnormal combustion suppressing means 73 performs the processing after step S28 in FIG. Execute. That is, the presence / absence of lock-up and the temperature T6 of the lock-up clutch LC are determined (steps S28 and S29), and the control for sliding the lock-up clutch LC according to the result (step S30) or the intake valve 9 One of the controls (step S31) for retarding the closing timing is executed.

  Next, a description will be given of the control operation when it is determined NO in step S16 of FIG. 8, that is, when any of the first to third gears is selected as the gear position of the multi-stage transmission 32. In this case, the abnormal combustion suppressing means 73 executes control for determining whether or not the gear position of the multi-stage transmission 32 is the third speed (step S21). The frictional engagement elements that are engaged in the multi-stage transmission 32 at the third speed are the forward clutch C1 and the 3-4 clutch C2, as shown in FIG.

  When it is determined YES in step S21 and it is confirmed that the third speed is selected, the abnormal combustion suppression means 73 determines that the temperature T1 of the forward clutch C1 read in step S1 of FIG. Control for determining whether or not the threshold value is higher than the threshold value T1a is executed (step S22).

  When it is determined NO in step S22 and it is confirmed that the temperature T1 of the forward clutch C1 is equal to or lower than the threshold value T1a, the abnormal combustion suppression means 73 slides the forward clutch C1, thereby causing the engine speed Ne. Is raised to a value on the higher rotation side than the abnormal combustion risk area PA (step S23).

  On the other hand, when it is determined as YES in step S22 and it is confirmed that the temperature T1 of the forward clutch C1 is higher than the threshold value T1a, the abnormal combustion suppression means 73 is read in step S1 of FIG. Control is performed to determine whether or not the temperature T2 of the four clutch C2 is higher than a predetermined threshold value T2a (step S24).

  When it is determined NO in Step S24 and it is confirmed that the temperature T2 of the 3-4 clutch C2 is equal to or lower than the threshold value T2a, the abnormal combustion suppression means 73 proceeds to Step S18, and the 3-4 clutch Control is performed to increase the engine speed Ne by sliding C2.

  On the other hand, if it is determined as YES in step S24 and it is confirmed that the temperature T2 of the 3-4 clutch C2 is higher than the threshold value T2a, the abnormal combustion suppressing means 73 performs the processing after step S28 in FIG. Execute. That is, the presence / absence of lock-up and the temperature T6 of the lock-up clutch LC are determined (steps S28 and S29), and the control for sliding the lock-up clutch LC according to the result (step S30) or the intake valve 9 One of the controls (step S31) for retarding the closing timing is executed.

  Next, a description will be given of the control operation when NO is determined in step S21 in FIG. 8, that is, when the first speed or the second speed is selected as the gear position of the multi-stage transmission 32. In this case, the abnormal combustion suppressing means 73 shifts to step S25 of FIG. 9 and executes control for determining whether or not the gear position of the multi-stage transmission 32 is the second speed (step S21). The frictional engagement elements that are engaged in the multi-stage transmission 32 at the second speed are the forward clutch C1 and the 2-4 brake B2, as shown in FIG.

  When it is determined YES in step S25 and it is confirmed that the second speed is selected, the abnormal combustion suppression means 73 determines that the temperature T1 of the forward clutch C1 read in step S1 of FIG. Control for determining whether or not the threshold value is higher than the threshold value T1a is executed (step S26).

  When it is determined NO in step S26 and it is confirmed that the temperature T1 of the forward clutch C1 is equal to or lower than the threshold value T1a, the abnormal combustion suppression means 73 proceeds to step S23 in FIG. Control is performed to increase the engine speed Ne by sliding.

  On the other hand, if it is determined YES in step S26 and it is confirmed that the temperature T1 of the forward clutch C1 is higher than the threshold value T1a, the abnormal combustion suppression means 73 proceeds to step S19 in FIG. -4 Control for determining whether the temperature T5 of the brake B2 is higher than the threshold value T5a is executed. And if the determination here is YES, the control which slides 2-4 brake B2 will be performed (step S20), and if it is NO, it will move to step S28 after FIG. 9, and will slide the lockup clutch LC. Alternatively, control for retarding the closing timing of the intake valve 9 is executed.

  Next, a description will be given of the control operation when it is determined NO in step S25 of FIG. 9, that is, when the first speed is selected as the gear position of the multi-stage transmission 32. When the first speed is selected, in the multi-stage transmission 32, as shown in FIG. 4, the forward clutch C1 is engaged as a friction engagement element, and the one-way clutch C4 is locked.

  When it is determined NO in step S25 of FIG. 9 and it is confirmed that the gear position is the first speed, the abnormal combustion suppression means 73 determines that the temperature T1 of the forward clutch C1 read in step S1 of FIG. Control for determining whether or not the threshold value is higher than a predetermined threshold value T1a is executed (step S27).

  When it is determined NO in step S27 and it is confirmed that the temperature T1 of the forward clutch C1 is equal to or lower than the threshold value T1a, the abnormal combustion suppressing means 73 proceeds to step S23 in FIG. Is executed to increase the engine rotation speed Ne. On the other hand, when it is determined YES in step S27 and it is confirmed that the temperature T1 of the forward clutch C1 is higher than the threshold value T1a, the process proceeds to step S28 and subsequent steps in FIG. 9 to slide the lockup clutch LC. Alternatively, control for retarding the closing timing of the intake valve 9 is executed.

  As described above, in the pre-ignition suppression control shown in FIGS. 8 and 9, the temperature of the frictional engagement element corresponding to the gear position of the multi-stage transmission 32 is checked, and the temperature is set to a predetermined threshold (T1a, T2a, etc.). ) If below, control is performed to increase the engine speed Ne by sliding any of the frictional engagement elements (clutch C1 to C3, brakes B1 and B2) of the multi-stage transmission 32 (steps S13, S15, S18, S20, S23). On the other hand, if the temperature is higher than the threshold value, the engagement state and the temperature of the lockup clutch LC that is the friction engagement element of the torque converter 31 are checked, and the lockup clutch LC is in the engagement state and the temperature is a predetermined threshold value. If (T6a) or less, control is performed to increase the engine speed Ne by sliding the lock-up clutch LC (step S30). Furthermore, if the lock-up clutch LC is not engaged or if the temperature is higher than a predetermined threshold value, a control is executed to retard the effective compression ratio by retarding the closing timing of the intake valve 9 (step S31). .

  Returning to the flowchart of FIG. 7 again, the control operation when it is determined NO in step S3, that is, when it is confirmed that pre-ignition has not occurred will be described. In this case, the abnormal combustion suppression means 73 of the ECU 70 is “1” indicating that the abnormal combustion suppression flag F is executing the above-described pre-ignition suppression control (the flow in FIGS. 8 and 9). Control to determine whether or not is executed (step S6).

  When it is determined as YES in step S6 and it is confirmed that the pre-ignition suppression control is being executed, the operating state determination means 71 of the ECU 70 determines the engine speed Nep when the pre-ignition suppression control is canceled at this time. The control for calculating is executed (step S7).

  For example, as the pre-ignition suppression control, the control of sliding any of the frictional engagement elements (clutch C1 to C3, brake B1, B2, lockup clutch LC) of the automatic multi-stage transmission 30 (step S13 in FIGS. 8 and 9). , S15, S18, S20, S23, or S30) is executed, and the engine speed Ne is being increased to a value greater than the upper limit rotational speed Ne0 of the abnormal combustion risk area PA. Based on the engine rotational speed Ne that is sequentially input during the operation and the decrease in rotational speed that is predicted when the frictional engagement element is released from slipping (that is, when the frictional engagement element is completely engaged). Thus, the engine speed Nep after the cancellation is calculated. In addition, when the control (step S31 in FIG. 9) for reducing the effective compression ratio by retarding the closing timing of the intake valve 9 is executed as the pre-ignition suppression control, the engine is not canceled even if the control is canceled. Since the rotation speed does not change, the engine rotation speed Ne that is sequentially input during the control is directly used as the engine rotation speed Nep after the release.

  When the engine rotation speed Nep after the cancellation of the pre-ignition suppression control is calculated as described above, the operation state determination means 71 of the ECU 70 determines that the engine rotation speed Nep after the cancellation is in the abnormal combustion risk area PA. The control for determining whether or not the upper limit rotational speed Ne0 is greater is executed (step S8).

  When it is determined as YES in step S8 and it is confirmed that the engine rotational speed Nep after release> the upper limit rotational speed Ne0, that is, even if the pre-ignition suppression control is canceled, the engine operating state is in an abnormal combustion risk region. When it is predicted that the engine will not return to PA, the abnormal combustion suppression means 73 of the ECU 70 performs the above-described pre-ignition suppression control (that is, control for sliding the frictional engagement element or retarding the closing timing of the intake valve 9). Control to cancel is executed (step S9). And the control which inputs "0" showing that the preignition suppression control is not performed to the said abnormal combustion suppression flag F is performed (step S10).

(1-5) Operational Effects As described above, the engine of the first embodiment detects abnormal combustion (pre-ignition) in which the air-fuel mixture self-ignites before the normal combustion start timing by spark ignition. The ECU 70 includes an abnormal combustion detection unit 72 and an abnormal combustion suppression unit 73 that executes predetermined control for suppressing the occurrence of pre-ignition when the detection unit 72 detects a pre-ignition. The abnormal combustion suppression means 73 is, for example, a friction engagement element of the automatic multi-stage transmission 30, that is, the clutches C1 to C3 of the multi-stage transmission 32, the brakes B1 and B2, and the torque converter as control for suppressing the pre-ignition. Control for increasing the engine rotational speed Ne by sliding any of the 31 lockup clutches LC (any one of steps S13, S15, S18, S20, S23, and S30 in FIGS. 8 and 9) is executed. According to such a configuration, there is an advantage that abnormal combustion can be effectively suppressed without particularly affecting engine performance.

  That is, in the first embodiment, when abnormal combustion (pre-ignition) due to self-ignition is detected, any of the frictional engagement elements C1 to C3, B1, B2, and LC of the automatic multi-stage transmission 30 is slid to the engine. By increasing the rotational speed Ne, the operating state is shifted from the low rotation side region (abnormal combustion risk region PA) where pre-ignition is likely to occur to the outside thereof. For example, when the pre-ignition occurs, the intake valve Unlike the case where the control for retarding the closing timing of 9 (step S31 in FIG. 9) is performed uniformly, the occurrence of pre-ignition can be effectively suppressed without particularly affecting the engine performance.

  For example, even if the closing timing of the intake valve 9 is suddenly retarded without performing the slip control of the frictional engagement element as described above, it is possible to reduce the effective compression ratio of the engine and suppress the occurrence of pre-ignition. However, if it does in this way, there exists a problem that the output torque of an engine will fall by the fall of a compression ratio.

  On the other hand, when pre-ignition occurs as in the first embodiment, first, when the engine speed Ne is increased by sliding the frictional engagement element of the automatic multi-stage transmission 30, the pre-ignition speed is increased. By forcibly shifting the operating state to a region where ignition is difficult to occur (outside the abnormally burnable region PA), it is possible to effectively suppress the occurrence of pre-ignition without causing a decrease in output torque as described above. There are advantages.

  More specifically, in the first embodiment, when pre-ignition is detected, control is first performed to slide any one of the frictional engagement elements (clutch C1 to C3, brakes B1 and B2) of the multi-stage transmission 32 (FIG. 8). Steps S13, S15, S18, S20, and S23) are executed, and when the temperature T1 to T5 of the friction engagement element becomes higher than a predetermined temperature (threshold values T1a to T5a), the friction engagement element (lock-up clutch) of the torque converter 31 is obtained. LC) is switched to the sliding control (step S30 in FIG. 9). According to such a configuration, the frictional engagement elements to be slid can be appropriately selected based on the temperatures of the frictional engagement elements C1 to C3, B1, and B2 of the multi-stage transmission 32, and the engine rotational speed Ne is generated when pre-ignition occurs. There is an advantage that the reliability of the automatic multi-stage transmission 30 as a product can be sufficiently ensured while emphasizing the responsiveness of control for increasing the speed.

  That is, when the frictional engagement elements (clutch C1 to C3, brakes B1 and B2) of the multi-stage transmission 32 are compared with the frictional engagement elements (lock-up clutch LC) of the torque converter 31, the frictional engagement element C1 of the multi-stage transmission 32. Since the hydraulic pressure supplied to C3, B1, and B2 is relatively small, the control for decreasing the hydraulic pressure to slide the friction surface can be executed with better responsiveness. Therefore, in the first embodiment, when a pre-ignition is detected, first, any one of the frictional engagement elements C1 to C3, B1, and B2 of the multi-stage transmission 32 is slid. As a result, the engine rotation speed Ne can be increased with better responsiveness, and the pre-ignition can be more quickly suppressed.

  However, in order to suppress the pre-ignition, if only the above-described control for sliding the frictional engagement elements C1 to C3, B1, and B2 of the multi-stage transmission 32 is performed, particularly under a situation where the pre-ignition occurs frequently. The temperatures T1 to T5 of the frictional engagement elements C1 to C3, B1 and B2 are excessively increased, which may cause problems such as seizure. Therefore, in the first embodiment, when all of the frictional engagement elements to be slid out of the frictional engagement elements C1 to C3, B1, and B2 of the multi-stage transmission 32 become higher than a predetermined temperature, the lockup clutch of the torque converter 31 is used. Switch to the control of sliding LC. Thereby, generation | occurrence | production of a preignition can be suppressed, preventing reliably that the friction engaging elements C1-C3, B1, B2 of the multistage transmission 32 rise in temperature too much.

  The lock-up clutch LC has a larger friction surface than the frictional engagement elements C1 to C3, B1 and B2 of the multi-stage transmission 32, and thus has a large heat capacity and a relatively high temperature even when slip control is performed. hard. Therefore, unless the slip control of the lockup clutch LC is performed at a fairly high frequency, it is considered that the temperature of the lockup clutch LC does not rise excessively. Therefore, as shown in the first embodiment, when the frictional engagement elements C1 to C3, B1 and B2 of the multi-stage transmission 32 are at a high temperature, the control for sliding the lockup clutch LC of the torque converter 31 is performed. When the engine speed is switched to, even if it is necessary to increase the engine speed Ne for a long time in order to suppress the pre-ignition, there is no problem due to an excessive temperature rise, and the automatic multi-stage transmission 30 There is an advantage that sufficient reliability can be secured.

  However, even in the case of the lock-up clutch LC having a large heat capacity as described above, if the slip control is performed for an excessively long time, the temperature T6 may be excessively increased (exceeding the threshold value T6a). Therefore, in the first embodiment, when the temperature of the lock-up clutch LC of the torque converter 31 becomes too high, the control is performed to retard the effective compression ratio by retarding the closing timing of the intake valve 9 (FIG. 9). Step S31). As a result, the output torque of the engine is sacrificed to some extent, but it is possible to reliably prevent problems due to the temperature rise of the lockup clutch LC, and to further improve the reliability of the automatic multi-stage transmission 30. However, since the priority for performing this control is the lowest, the frequency of the decrease in the output torque as described above is considerably low, and it is not considered to be a big problem.

  In the first embodiment, for example, the friction engagement elements (clutch C1 to C3, brakes B1 and B2) of the multi-stage transmission 32 and the friction engagement element (lockup clutch LC) of the torque converter 31 are both hot. In addition, the control for reducing the effective compression ratio by retarding the closing timing of the intake valve 9 is executed (step S31). The control in step S31 creates a combustion condition in which pre-ignition is difficult to occur. Any change is possible, and the present invention is not limited to the valve timing change as described above. For example, instead of the control in step S31, the control is performed to make the air-fuel ratio richer than the stoichiometric air-fuel ratio, or the injection timing is such that at least part of the combustion injected from the injector 15 is injected during the compression stroke. Control for retarding may be executed. In this way, it is possible to reduce the in-cylinder temperature and suppress the occurrence of pre-ignition.

  However, enrichment of the air-fuel ratio and retarding of the fuel injection timing as described above cause deterioration in fuel efficiency and emission, which is also disadvantageous in terms of engine performance. However, even when such control is performed in place of step S31, control for sliding the frictional engagement element of the automatic multi-stage transmission 30 when the pre-ignition occurs is performed preferentially. According to the configuration of the first embodiment, it is possible to suppress the occurrence of pre-ignition without affecting the engine performance as much as possible.

  In the first embodiment, the friction engagement elements (clutch C1 to C3, brakes B1 and B2, brakes B1 and B2, etc.) of the automatic multi-stage transmission 30 are used as control for increasing the engine rotation speed Ne when the pre-ignition is detected. Any one of the lockup clutches LC) is slid. However, when the multi-stage transmission 32 can form a large number of shift stages such as six or more speeds, the shift stage is switched to the deceleration side (shifting). The engine rotational speed Ne may be increased by lowering. If the gear ratio changes greatly due to downshifting, the driver may feel uncomfortable. However, if the gearbox has a relatively large number of gears, the gear ratio will not change that much if only one gear is dropped. , Driver's discomfort can be alleviated.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, an automatic continuously variable transmission 130 that can change the gear ratio steplessly is used as an automatic transmission connected to the engine.

(2-1) Configuration of Automatic Transmission The configuration of the automatic continuously variable transmission 130 is shown in FIG. As shown in the figure, the automatic continuously variable transmission 130 includes a torque converter 131 (corresponding to a starting device according to the present invention), a forward / reverse switching device 132, and a continuously variable transmission 133.

  The torque converter 131 transmits a driving force (rotational force of the crankshaft 4) input from the engine to the forward / reverse switching device 132, and main components thereof include a pump impeller 134, a turbine runner 135, a stator. 136, a turbine shaft 137, a lock-up clutch LC, and the like. The configuration of such a torque converter 131 is the same as that of the torque converter 31 of the automatic multi-stage transmission 30 in the first embodiment. Therefore, the description of the specific functions of the above components (pump impeller 134, turbine runner 135, etc.) is omitted here.

  The forward / reverse switching device 132 transmits the rotation of the turbine shaft 137 that is the output shaft of the torque converter 131 to the continuously variable transmission 133 as it is, and reverses the rotation of the turbine shaft 137 to continuously variable the transmission 133. By selectively setting the state to be transmitted to the vehicle, the traveling direction of the vehicle is switched back and forth.

  Specifically, the forward / reverse switching device 132 includes a sun gear 140a, a ring gear 140d formed in a ring shape so as to surround the sun gear 140a, and a plurality of gears arranged between the sun gear 140a and the ring gear 140d. It has a planetary gear 140b and a carrier 140c that holds the planetary gear 140b. Further, a forward clutch C11 is provided between the ring gear 140d and the carrier 140c so as to connect the two in an intermittent manner, and the ring gear 140d is selectively connected to the transmission case 142 between the ring gear 140d and the transmission case 142. A reverse brake B12 is provided for fixing.

  The power transmission direction between the turbine shaft 137 and the sun gear 140a is switched in accordance with the intermittent engagement of the frictional engagement element including the forward clutch C11 and the reverse brake B12. Specifically, as shown in the engagement table of FIG. 11 (circles indicate engagement), the forward clutch C11 is engaged and the reverse brake B12 is released, so that the sun gear 140a moves in the same direction as the turbine shaft 137. It will be in the state which rotates, and the advancing direction of a vehicle is set to the advance side. On the other hand, when the forward clutch C11 is released and the reverse brake B12 is engaged, the sun gear 140a rotates in the direction opposite to the turbine shaft 137, and the traveling direction of the vehicle is set to the reverse side.

  The continuously variable transmission 133 is a transmission that can change the transmission ratio steplessly within a predetermined range, and the primary component 150 and the secondary pulley 151 are wound around these pulleys as main components. And an endless metal belt 152.

  The primary pulley 150 includes a primary shaft 150a connected to the sun gear 140a of the forward / reverse switching device 132, a conical member 150b fixed to the primary shaft 150a, and a conical member 150c movable in the axial direction with respect to the primary shaft 150a. The metal belt 152 is wound around a belt receiving groove having a V-shaped cross section formed between the conical members 150b and 150c. A cylindrical primary chamber 150d is formed at the rear of the conical member 150c, and a piston 150e fixed to the primary shaft 150a is disposed in the primary chamber 150d.

  The secondary pulley 151 has the same configuration as the primary pulley 150, and includes a secondary shaft 151a, a conical member 151b fixed to the secondary shaft 151a, and a conical member movable in the axial direction with respect to the secondary shaft 151a. 151c, and the metal belt 233 is wound around a belt receiving groove having a V-shaped cross section formed between the conical members 151b and 151c. A cylindrical secondary chamber 151d is formed at the rear portion of the conical member 151c, and a piston 151e fixed to the secondary shaft 151a is disposed in the secondary chamber 151d.

  Then, hydraulic oil is supplied to the primary chamber 150d of the primary pulley 150 and the secondary chamber 151d of the secondary pulley 151, respectively, and the conical members 150c and 151c are moved in the axial direction by the control of the hydraulic pressure, thereby the metal belt 152. The effective diameter with respect to is changed, and the gear ratio is changed steplessly accordingly. The driving force of the secondary shaft 151 a of the secondary pulley 151 is transmitted to the left and right drive shafts 145 via the differential device 144.

(2-2) Configuration of Control System FIG. 12 is a block diagram showing a control system of the engine of the second embodiment. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and the descriptions of the same components are omitted.

  Only the main differences will be described. In the present embodiment, as sensors for detecting the state quantity of the automatic continuously variable transmission 130, the forward / reverse sensor 160, the first temperature sensor 161, the second temperature sensor 162, the lockup A sensor 163 and a third temperature sensor 164 are provided. Specifically, the forward / reverse sensor 160 determines whether the forward / reverse switching device 132 is switched to the forward side or the reverse side based on the engaged state of the forward clutch C11 and the reverse brake B12. This is to detect whether it is set. The first temperature sensor 161 detects the temperature T11 of the forward clutch C11, and the second temperature sensor 162 detects the temperature T12 of the reverse brake B12. The lockup sensor 163 detects the engagement state (ON / OFF) of the lockup clutch LC of the torque converter 131, and the third temperature sensor 164 detects the temperature T13 of the lockup clutch LC. It is.

  The detection values of the sensors 160 to 164 are input to the ECU 70, and the abnormal combustion suppression means 73 of the ECU 70 detects the detection values of the sensors 160 to 164 as control (pre-ignition suppression control) for suppressing pre-ignition. Based on the above, the automatic continuously variable transmission 130 is operated, and control for increasing the engine rotational speed Ne is executed (details will be described later).

(2-3) Specific Example of Control Operation FIG. 13 is a diagram illustrating specific contents of the pre-ignition suppression control executed in the engine of the second embodiment. As a premise that the processing shown in this figure is executed, the processing shown in the flowchart of FIG. 7 in the first embodiment is executed as the main flow, and the flow is the processing of step S4 (pre-processing). It is assumed that the process shown in the flowchart of FIG. 13 is executed when the process shifts to (ignition suppression control). That is, in the main flow shown in FIG. 7, when it is confirmed that the engine is operating in the abnormal combustion risk area PA and pre-ignition has occurred (that is, YES in both steps S2 and S3). In the case of FIG. 13, the process of step S <b> 4 is executed next. As a specific content of the control, the flowchart of FIG. 13 is illustrated.

  When the processing of FIG. 13 is started, the abnormal combustion suppression means 73 determines whether or not the forward / reverse switching device 132 has set the traveling direction switching position to the reverse side based on the detection value of the forward / reverse traveling sensor 160. The detection control is executed (step S101).

  If it is determined YES in step S101 and it is confirmed that the reverse combustion side is set, the abnormal combustion suppression means 73 determines that the temperature T12 of the reverse brake B12 input from the second temperature sensor 162 is in advance. Control for determining whether or not the threshold value is higher than the predetermined threshold value T12a is executed (step S102).

  When it is determined NO in step S102 and it is confirmed that the temperature T12 of the reverse brake B12 is equal to or lower than the threshold value T12a, the abnormal combustion suppression means 73 slides the reverse brake B12 to increase the engine speed Ne. The control to be executed is executed (step S103). That is, the hydraulic pressure supplied to the reverse brake B12 is made lower than the hydraulic pressure required for engagement, and the reverse brake B12 is intentionally slid, so that the engine speed Ne is reduced as shown by the arrow R in FIG. Increase to a value higher than the upper limit rotational speed Ne0 of the abnormal combustion risk area PA, thereby avoiding the occurrence of pre-ignition.

  On the other hand, when it is determined YES in step S102 and it is confirmed that the temperature T12 of the reverse brake B12 is higher than the threshold value T12a, the abnormal combustion suppression means 73 proceeds to step S106, and the torque converter 131 is activated. Control is performed to determine whether or not the lockup state exists. That is, based on the detection value of the lockup sensor 163, it is determined whether or not the torque converter 131 is in the lockup state by determining whether or not the lockup clutch LC is engaged.

  When it is determined YES in step S106 and it is confirmed that the lockup state is established, the abnormal combustion suppression means 73 determines that the temperature T13 of the lockup clutch LC input from the third temperature sensor 164 is predetermined. Control is performed to determine whether or not the threshold value T13a is higher (step S107).

  When it is determined NO in step S107 and it is confirmed that the temperature T13 of the lockup clutch LC is equal to or lower than the threshold value T13a, the abnormal combustion suppression means 73 slides the lockup clutch LC to rotate the engine. Control is executed to increase the speed Ne to a value on the higher rotation side than the abnormal combustion risk area PA (step S108).

  On the other hand, if NO is determined in step S106 and it is confirmed that the lock-up state is not established, or YES is determined in step S107 and it is confirmed that the temperature T13 of the lock-up clutch LC is higher than the threshold value T13a. In this case, the abnormal combustion suppression means 73 operates the continuously variable transmission 133 to change the speed ratio to the speed reduction side (that is, the state where the input speed from the engine is decelerated at a larger ratio). Thus, control for increasing the engine rotation speed Ne to a value on the higher rotation side than the abnormal combustion risk area PA is executed (step S109).

  Next, a description will be given of the control operation when it is determined NO in step S101, that is, when the forward / reverse switching device 132 sets the traveling direction switching position to the forward side. In this case, the abnormal combustion suppression means 73 executes control for determining whether or not the temperature T11 of the forward clutch C11 input from the first temperature sensor 161 is higher than a predetermined threshold value T11a (step). S104).

  When it is determined NO in step S104 and it is confirmed that the temperature T11 of the forward clutch C11 is equal to or lower than the threshold value T11a, the abnormal combustion suppression means 73 slides the forward clutch C11, thereby causing the engine speed Ne. Is raised to a value on the higher rotation side than the abnormal combustion risk area PA (step S105).

  On the other hand, if it is determined as YES in step S104 and it is confirmed that the temperature T11 of the forward clutch C11 is higher than the threshold value T11a, the abnormal combustion suppressing means 73 performs the processing after step S106. That is, it is determined whether or not there is a lockup and the temperature T13 of the lockup clutch LC (steps S106 and S107), and the lockup clutch LC is slid according to the result (step S108) or the continuously variable transmission. One of the control (step S109) which changes the gear ratio of 133 to the deceleration side is performed.

(2-4) Operational Effect As described above, in the engine of the second embodiment, when the pre-ignition is detected, the forward clutch C11 and the reverse brake B12 of the forward / reverse switching device 132 or the torque converter 131 are detected. The control of increasing the engine speed Ne is performed by sliding any one of the lockup clutches LC or changing the gear ratio of the continuously variable transmission 133 to the deceleration side (step S103, S105, S018, S109). According to such a configuration, like the first embodiment described above, there is an advantage that the occurrence of pre-ignition can be effectively suppressed without particularly affecting the engine performance.

  More specifically, in the second embodiment, when pre-ignition is detected, control is first performed to slide one of the frictional engagement elements (forward clutch C11, reverse brake B12) of the forward / reverse switching device 132 (step S103, S105) is executed, and when the temperatures T11 and T12 of the respective frictional engagement elements become higher than predetermined temperatures (threshold values T11a and T12a), the control is switched to the control of sliding the frictional engagement elements (lock-up clutch LC) of the torque converter 31 ( Step S108) Furthermore, when the temperature T13 of the lock-up clutch LC becomes higher than a predetermined temperature (threshold value T13a), the control is switched to the control for changing the speed ratio of the continuously variable transmission 133 to the deceleration side (Step S109). . According to such a configuration, which frictional engagement element should be slid based on the temperature of each frictional engagement element C11, B12, LC of the torque converter 131 and the forward / reverse switching device 132, or the continuously variable transmission As a product of the automatic continuously variable transmission 130, it is possible to make an appropriate selection as to whether or not the transmission ratio of 133 should be changed, and emphasize the responsiveness of control for increasing the engine rotational speed Ne when pre-ignition occurs. There is an advantage that sufficient reliability can be secured.

  That is, when the frictional engagement elements (forward clutch C11, reverse brake B12) of the forward / reverse switching device 132 are compared with the frictional engagement elements (lock-up clutch LC) of the torque converter 131, the frictional engagement element C11 of the forward / reverse switching device 132 is compared. , B12 is supplied with a relatively small hydraulic pressure, so that the control for decreasing the hydraulic pressure to slide the friction surface can be executed with better responsiveness. Therefore, in the second embodiment, when pre-ignition is detected, one of the frictional engagement elements C11 and B12 of the forward / reverse switching device 132 is first slid. As a result, the engine rotation speed Ne can be increased with better responsiveness, and the pre-ignition can be more quickly suppressed.

  However, if only the above-described control for sliding the frictional engagement elements C11 and B12 of the forward / reverse switching device 132 is performed in order to suppress the preignition, the frictional engagement is performed particularly in a situation where the frequency of preignition is high. There is a possibility that the temperatures T11 and T12 of the elements C11 and B12 rise excessively and cause problems such as seizure. Therefore, in the second embodiment, when the frictional engagement element to be slid out of the frictional engagement elements C11 and B12 of the forward / reverse switching device 132 becomes higher than a predetermined temperature, the lockup clutch LC of the torque converter 131 is slid. Switch to control. The control for sliding the lockup clutch LC is inferior in control responsiveness compared to the case where the frictional engagement elements C11 and B12 of the forward / reverse switching device 132 are slid as described above, but the lockup clutch LC is more susceptible to the friction. Since the area of the friction surface is larger than that of the fastening elements C11 and B12, it is advantageous in that the temperature does not easily rise, and can withstand slip control over a relatively long time.

  However, even in the case of the lock-up clutch LC having a large heat capacity as described above, if the slip control is performed for an excessively long time, the temperature T13 may be excessively increased (exceeding the threshold value T13a). Therefore, in the second embodiment, when even the lock-up clutch LC of the torque converter 131 reaches a high temperature, the gear ratio of the continuously variable transmission 133 is changed to the deceleration side to switch to control for increasing the engine rotational speed Ne. (Step S109). As a result, it is possible to continue the control to increase the engine rotational speed Ne while reliably preventing the frictional engagement elements C11, B12, and LC of the torque converter 131 and the forward / reverse switching device 132 from excessively rising in temperature. There is an advantage that it is possible to effectively suppress the occurrence of pre-ignition while eliminating the influence on the engine. Further, since the gear ratio can be changed steplessly by the continuously variable transmission 133, the engine speed can be appropriately increased by a necessary amount, and pre-ignition can be suppressed without giving a driver a particularly uncomfortable feeling. be able to.

30 Automatic multi-stage transmission (automatic transmission)
31 Torque converter (starting device)
32 Multi-speed transmission 72 Abnormal combustion detection means 73 Abnormal combustion suppression means 130 Automatic continuously variable transmission (automatic transmission)
131 Torque converter (starting device)
132 Forward / reverse switching device 133 Continuously variable transmission C1 to C3 Clutch (friction engagement element of multi-stage transmission)
B1, B2 Brake (Friction engagement element of multi-stage transmission)
C11 Clutch (Friction engagement element of forward / reverse switching device)
B12 Brake (Friction engagement element for forward / reverse switching device)
LC lock-up clutch (Friction engagement element of starter)

Claims (7)

Abnormal combustion detection means for detecting abnormal combustion in which the air-fuel mixture self-ignites before the normal combustion start timing by spark ignition, and for suppressing the occurrence of abnormal combustion when the abnormal combustion is detected by the detection means A spark ignition type engine control device comprising an abnormal combustion suppressing means for executing the predetermined control of
The spark ignition engine control apparatus characterized in that the predetermined control by the abnormal combustion suppressing means increases the rotational speed of the engine by controlling a power transmission element of an automatic transmission connected to the engine. . The control device for the spark ignition engine according to claim 1,
A spark ignition type engine control apparatus characterized in that the predetermined control by the abnormal combustion control means increases the engine speed by sliding a frictional engagement element of an automatic transmission. The control device for the spark ignition engine according to claim 2,
The automatic transmission is an automatic multi-stage transmission including a multi-stage transmission capable of forming a plurality of shift stages and a starting device that transmits engine driving force to the transmission.
A spark ignition type engine control device characterized in that the predetermined control by the abnormal combustion control means increases the engine speed by sliding the friction engagement element of the multi-stage transmission. The control device for the spark ignition engine according to claim 2,
The automatic transmission is an automatic multi-stage transmission including a multi-stage transmission capable of forming a plurality of shift stages and a starting device that transmits engine driving force to the multi-stage transmission.
The spark ignition type engine control device characterized in that the predetermined control by the abnormal combustion control means increases the engine speed by sliding the friction engagement element of the starting device. The control device for the spark ignition engine according to claim 2,
The automatic transmission is an automatic multi-stage transmission including a multi-stage transmission capable of forming a plurality of shift stages and a starting device that transmits engine driving force to the multi-stage transmission.
When the abnormal combustion is detected by the abnormal combustion detection means, the abnormal combustion control means first performs control to slide the friction engagement element of the multi-stage transmission, and the friction engagement element of the multi-stage transmission exceeds a predetermined temperature. A control device for a spark ignition engine characterized by switching to a control for sliding the frictional engagement element of the starting device when the temperature is too high. The control device for the spark ignition engine according to claim 1,
The automatic transmission is an automatic continuously variable transmission including a continuously variable transmission capable of changing a transmission gear ratio steplessly,
A spark ignition type engine control device characterized in that the predetermined control by the abnormal combustion control means increases the engine speed by changing the speed ratio of the continuously variable transmission to a deceleration side. The control device for the spark ignition engine according to claim 6,
The automatic continuously variable transmission transmits the driving force of the engine to the continuously variable transmission, the forward / reverse switching device connected to the continuously variable transmission as the device for switching between forward and reverse, and the forward / backward switching device. A starting device,
When abnormal combustion is detected by the abnormal combustion detection means, the abnormal combustion control means first performs control to slide the friction engagement element of the forward / reverse switching device, and the friction engagement element of the forward / reverse switching device is predetermined. When the temperature is higher than the temperature, the control is switched to the control of sliding the frictional engagement element of the starter. Further, when the temperature of the frictional engagement element of the starter becomes higher than a predetermined temperature, the transmission ratio of the continuously variable transmission is reduced. A control device for a spark ignition engine, characterized in that the control is switched to a control to be changed to the side.

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