JP6525403B2 - Engine control device - Google Patents

Description

  The present invention relates to a control device for an engine, and more particularly to a control device for an engine provided with a variable displacement turbocharger capable of changing the amount of exhaust gas flowing into an exhaust turbine.

  Japanese Patent No. 3287276 (Patent Document 1) describes a control device of a variable displacement turbocharger. In the turbocharger described herein, the turbine wheel is rotated by blowing exhaust gas from an internal combustion engine, and furthermore, the compressor wheel connected to the turbine wheel is rotated to force air in the intake passage. In the combustion chamber of the internal combustion engine. Further, in this turbocharger, the flow velocity of the exhaust gas blown to the turbine wheel via the exhaust gas flow path is adjusted by changing the gap between the nozzle vanes, and a variable displacement turbocharger is obtained.

  Furthermore, in the controller of the variable displacement turbocharger disclosed in Patent Document 1, when the racing state of the internal combustion engine is detected, the variable displacement mechanism is controlled in such a direction that the exhaust pressure of the internal combustion engine does not increase. Thus, in the invention described in Patent Document 1, an increase in engine speed during racing is hindered based on an increase in back pressure of the internal combustion engine during racing, or the speed of the internal combustion engine against depression of the accelerator pedal. Is prevented from rising at an appropriate speed (see paragraph 0012 of Patent Document 1).

Patent No. 3287276

  However, under predetermined operating conditions, it has been confirmed that abnormal combustion occurs in the combustion chamber of the engine and causes deterioration of the engine if the engine speed in the racing state increases too much. In particular, it has been found that this problem is noticeable if the variable displacement mechanism in the turbocharger has a temporary or continuous failure and the flow velocity of the exhaust blown to the turbine wheel is too high.

  Therefore, the present invention can provide an engine control device capable of suppressing the occurrence of abnormal combustion in the engine in the racing state and ensuring sufficient blow-up of the engine speed in the case of racing. The purpose is to

In order to solve the problems described above, the present invention is a control device of an engine provided with a variable displacement turbocharger capable of changing the amount of exhaust gas flowing into an exhaust turbine, the variable displacement turbocharger being an exhaust turbine Racing determination means for determining a racing state in which the vehicle is substantially stopped and the engine load is substantially unloaded, and the movable vane for changing the flow velocity of the exhaust gas flowing into the An engine speed sensor that detects the engine speed, and the racing determination means determines a racing state of the engine, and when the engine speed detected by the engine speed sensor becomes equal to or higher than a predetermined first engine speed have a, an engine control unit for controlling the engine such that the output is reduced, the engine control unit, racing determining means determines the racing state of the engine,且When the rotation speed detected by the rotation speed sensor rises to a predetermined second rotation speed lower than the first rotation speed, the movable vanes are controlled to reduce the flow velocity of the exhaust flowing into the exhaust turbine, and engine control means When the racing determination means determines the racing state of the engine and the rotational speed detected by the rotational speed sensor rises to the first rotational speed, the supply amount of fuel injected from the fuel injection valve of the engine is limited. It is characterized in that it is configured to reduce the output of the engine .

  In the present invention thus configured, the racing determination means determines whether or not the engine is in the racing state, and the revolution sensor detects the revolution speed of the engine. The engine control means is determined by the racing determination means that the engine is in a racing state, and the engine output is reduced when the rotational speed detected by the rotational speed sensor becomes equal to or higher than a predetermined first rotational speed. Control.

  According to the present invention configured as described above, the engine control means reduces the output of the engine when the engine is in the racing state and reaches a predetermined first rotation speed or more. Abnormal combustion can be suppressed. Further, even in the racing state, the engine control means does not reduce the output of the engine until the number of revolutions of the engine reaches the first number of revolutions, so the number of revolutions of the engine rapidly rises with the depression of the accelerator pedal, Sufficient racing performance can be secured.

  According to the present invention configured as described above, when the engine is in a racing state and the rotational speed is increased to a predetermined second rotational speed, the movable vanes are controlled and the flow velocity of the exhaust flowing into the exhaust turbine is reduced. Therefore, the number of revolutions of the exhaust turbine is excessively increased, and the supercharging pressure is excessively increased, whereby the occurrence of abnormal combustion in the combustion chamber can be suppressed. In addition, since the movable vanes are mechanically operated, a relatively large response delay occurs to the control signal. According to the present invention configured as described above, since the second rotation speed is set to a rotation speed lower than the first rotation speed, the engine responds in response to the operation of the movable vane at the time of a sharp rise in the engine rotation speed. Even when there is a delay, the flow speed of the exhaust flowing into the exhaust turbine can be reduced until the engine speed reaches the first speed. This makes it possible to reduce the flow velocity of the exhaust before the engine speed reaches the first speed, and to prevent an excessive increase in the supercharging pressure, thus ensuring the occurrence of abnormal combustion. It can be avoided.

  In the present invention, preferably, the first rotational speed is set to a rotational speed at which the intake of the oil adhering to the inside of the intake passage of the engine into the combustion chamber starts to occur.

  In the racing state of the engine, when the engine speed rises above the first speed in the engine racing state, the oil adhering to the intake passage of the engine is drawn into the combustion chamber due to the engine speed rapidly rising. , It was found that abnormal combustion occurred. According to the present invention configured as described above, since the first rotation speed for reducing the output of the engine is set to the rotation speed at which the intake of oil into the combustion chamber starts to occur, the oil is rapidly reduced in the engine The abnormal combustion that occurs due to being sucked into can be reliably suppressed.

  In the present invention, preferably, the first rotation number is set to a rotation number at which the flow velocity of intake air in the intake passage of the engine is equal to or higher than a predetermined flow velocity.

  In the racing state of the engine, when the flow velocity of the intake air in the intake passage of the engine rises to a predetermined flow velocity or more in the racing state of the engine, the oil adhering to the intake passage of the engine is drawn into the combustion chamber and abnormal combustion occurs. I figured out what to do. According to the present invention configured as described above, since the first rotation speed for reducing the output of the engine is set to the rotation speed at which the flow velocity of intake air in the intake passage of the engine is equal to or higher than the predetermined flow velocity, It is possible to reliably suppress the abnormal combustion that occurs due to the sudden intake of oil.

  In the present invention, preferably, the apparatus further comprises an attached oil amount estimation means for estimating the amount of oil adhering to the intake passage of the engine, and the engine control means causes the racing determination means to determine the racing state of the engine. And, even if the rotation speed detected by the rotation speed sensor becomes equal to or higher than the first rotation speed, the amount of oil adhering to the inside of the intake passage is smaller than or equal to the predetermined amount by the adhering oil amount estimation means If it is determined that the engine output is not reduced.

  According to the present invention configured as described above, the adhering oil amount estimating means estimates the amount of oil adhering to the inside of the intake passage, and when the amount of oil is equal to or less than a predetermined amount, the output of the engine is It will not be reduced. As a result, the amount of oil deposited is small, and engine power is not reduced in a state where abnormal combustion is unlikely to occur, and racing performance can be further improved.

  In the present invention, preferably, the adhering oil amount estimating means determines the amount of oil adhering to the intake passage based on the time when the engine is operated at light load or the frequency at which the engine is operated at light load. It is determined whether it is less than a predetermined amount.

  Generally, blowby gas that has leaked from the combustion chamber of the engine into the crankcase is returned to the intake system via the gas reduction path. Engine oil in the crankcase is mixed in the blowby gas, and even if the blowby gas is returned to the intake system via the oil separator, the oil adheres in the intake passage. Further, when the engine is operated at a relatively high load, the oil mixed in the blowby gas flows into the combustion chamber together with the intake because the flow velocity of the intake flowing through the intake passage is high, and flows into the intake passage. It hardly adheres. On the other hand, when the engine is operated at a light load, the flow rate of the intake air flowing in the intake passage is slow, so the oil mixed in the blowby gas tends to adhere to the inner wall surface of the intake passage. For this reason, when the engine is operated with a light load for a long time, or after the light load operation is repeated, a large amount of oil adheres to the inner wall surface of the intake passage. As the pressure rises sharply, the oil that has adhered adheres into the combustion chamber at once, causing abnormal combustion. According to the present invention configured as described above, the adhering oil amount estimating means estimates the adhesion of oil based on the time when the engine is operated at light load or the frequency at which the engine is operated at light load. Therefore, the state where abnormal combustion is likely to occur can be reliably detected, and racing performance can be improved while reliably suppressing the occurrence of abnormal combustion.

  According to the engine control device of the present invention, it is possible to suppress the occurrence of abnormal combustion in the engine in the racing state while securing a sufficient blow-up of the engine speed when racing is performed.

FIG. 1 is a view showing an engine system to which a control device of an engine according to a first embodiment of the present invention is applied. FIG. 1 is a cross-sectional view of a turbocharger provided in an engine system to which a first embodiment of the present invention is applied. FIG. 3 is a cross-sectional view of a turbocharger provided in an engine system to which the first embodiment of the present invention is applied, taken along line III-III in FIG. 2; It is a block diagram showing each sensor connected to the control device of the engine by a 1st embodiment of the present invention, and an actuator. It is a flowchart of abnormal combustion suppression control performed by the control device for an engine according to the first embodiment of the present invention. It is a figure which shows the relationship between the engine speed and the opening degree of a nozzle in, when abnormal combustion suppression control is performed. FIG. 6 is a view showing a relationship between an engine speed and an opening degree of a fuel injection amount when abnormal combustion suppression control is executed. It is a flowchart of abnormal combustion suppression control executed by a control device of an engine according to a second embodiment of the present invention.

The preferred embodiments of the present invention will now be described with reference to the accompanying drawings.
FIG. 1 is a view showing an engine system 1 to which a control device for an engine according to a first embodiment of the present invention is applied.

  The engine system 1 includes an engine 2 that is a diesel engine, an intake system 4 that supplies intake air to the engine 2, a fuel supply system 6 that supplies fuel to the engine 2, and exhaust gas discharged from the engine 2 It has an exhaust system 8 for discharging the engine 2 to the outside of a vehicle equipped with the engine 2, a plurality of sensors for detecting various states related to the engine system 1, and a control device 10 for controlling the engine system 1. There is.

  The engine 2 is a multi-cylinder engine having a plurality of cylinders 12a (only one is shown in FIG. 1), and is disposed on the cylinder block 12 provided with the plurality of cylinders 12a, and the cylinder block 12 The cylinder head 14 and the oil pan 16 disposed under the cylinder block 12 and used to lubricate the drive system of the engine 2 are stored. A piston 18 is inserted in each cylinder 12a of the engine E so as to be capable of reciprocating in the cylinder 12a, and a combustion chamber is formed by the top surface of the piston 18, the side wall of the cylinder 12a and the lower surface of the cylinder head 14. 20 are formed for each cylinder 12a.

The piston 18 is connected via a connecting rod 22 to a crankshaft 24 which is an output shaft of the engine 2, and the crankshaft 24 is rotated by the reciprocating motion of the piston 18.
In the cylinder head 14, an intake port 26 and an exhaust port 28 are formed for each cylinder 12a, and an intake valve 30 and an exhaust valve 32 for opening and closing an opening on the combustion chamber 20 side of the intake port 26 and the exhaust port 28 are provided. Each is provided. Further, each cylinder head 14 is provided with a fuel injection valve 34 for supplying fuel into the combustion chamber 20.
Further, the engine 2 is provided with an engine rotational speed sensor 36 that detects the rotational speed of the engine 2 from the rotational angle of the crankshaft 24.

  The intake system 4 includes an intake passage 38 communicating with the intake port 26 of each cylinder 12 a of the engine 2. An air cleaner 40 for filtering intake air introduced from the outside of the vehicle is provided at the intake upstream end of the intake passage 38. On the other hand, a surge tank 42 for temporarily storing the intake air supplied to the engine 2 is provided in the vicinity of the intake downstream end of the intake passage 38.

  Between the air cleaner 40 and the surge tank 42 in the intake passage 38, a compressor 44a of the turbocharger 44 and an intake shutter valve 46 for adjusting the flow rate of intake air to the combustion chamber 20 of each cylinder 12a; And an intercooler 48 for cooling the air supercharged by the compressor 44a.

  The fuel supply system 6 has a fuel tank 50 for storing fuel, and a fuel supply passage 52 for supplying fuel from the fuel tank 50 to the fuel injection valve 34. In addition, a fuel pump 54 is provided on the fuel supply passage 52. The fuel stored in the fuel tank 50 is supplied by the fuel pump 54 to the fuel injection valve 34 via the fuel supply passage 52.

  The exhaust system 8 has an exhaust passage 56 through which the exhaust gas passes. The exhaust passage 56 communicates with the exhaust port 28 of each cylinder 12 a of the engine 2, and an exhaust manifold branched to each of the cylinders 12 a and connected to the exhaust port 28 at a connection portion between the engine 2 and the exhaust passage 56 (Not shown) is provided.

  On the exhaust downstream side of the exhaust manifold 56 in the exhaust passage 56, sequentially from the exhaust upstream side, by the connection portion between the high pressure EGR passage 58a of the high pressure EGR device 58 described later and the exhaust passage 56 and the exhaust gas passing through the exhaust passage 56 A turbine 44 b of the turbocharger 44 is provided which is rotated and rotationally drives the compressor 44 a by this rotation.

  Further, a gas extraction path 74 for extracting blowby gas generated in the crank chamber is connected to the engine 2, and the gas extraction path 74 is connected to a surge tank 42 of the intake system 4 via an oil separator 76. It is done.

  The engine system 1 of the present embodiment further includes a high pressure EGR device 58 as a device for recirculating a part of the exhaust gas to the intake side. The high pressure EGR device 58 connects a portion of the exhaust passage 56 between the exhaust manifold and the turbine 44 b of the turbocharger 44 and a portion of the intake passage 38 between the intercooler 48 and the surge tank 42. A high pressure EGR valve 58b is provided to adjust the flow rate of the exhaust gas passing through the high pressure EGR passage 58a, and the relatively high pressure exhaust gas discharged to the exhaust passage 56 is returned to the intake side.

  The turbocharger 44, which is a variable displacement turbocharger provided in the engine system 1 of the present embodiment, is compact so that supercharging can be performed efficiently even when the turbine 44b, which is an exhaust turbine, rotates at a low speed. The variable displacement type in which the flow velocity of the exhaust gas flowing into the turbine 44b can be adjusted by changing the flow passage cross-sectional area of the exhaust gas flowing into the turbine 44b according to the operating state of the engine 2 It is configured as a turbo charger (VGT turbo: Variable Geometry Turbo). At the inlet of the turbine 44b, that is, immediately upstream of the turbine 44b in the exhaust passage 56, a movable vane (movable member) 44c for adjusting the flow passage cross-sectional area of the exhaust gas is provided.

  Next, with reference to FIGS. 2 and 3, the structure around the turbine 44 b of the turbocharger 44 will be described. FIG. 2 is a cross-sectional view of the turbocharger 44 provided in the engine system 1. FIG. 3 is a cross-sectional view of the turbocharger 44 provided in the engine system 1 along the line III-III in FIG.

  As shown in FIGS. 2 and 3, the turbine 44b is disposed substantially at the center of a turbine chamber 60a formed in the turbine casing 60, and a plurality of movable vanes 44c are provided so as to surround the turbine 44b. It is provided. As shown in FIG. 3, each movable vane 44c is rotatably supported by a support shaft 44d which penetrates a wall on one side of the turbine chamber 60a (the wall on the right side of the movable vane 44c in FIG. 3). .

  Furthermore, when the movable vanes 44c are respectively pivoted around the support shaft 44d (clockwise in FIG. 2) and inclined so as to approach each other, the nozzles 62 formed between the movable vanes 44c are also formed. Since the flow rate of the exhaust gas for rotating the turbine 44b can be increased even when the opening degree (nozzle cross-sectional area) is narrowed small and the exhaust gas flow rate is small, high supercharging efficiency can be obtained. On the other hand, when the movable vanes 44c rotate in the opposite direction to the above (rotate counterclockwise in FIG. 2) and incline away from each other, the nozzle cross-sectional area increases and the exhaust flow rate increases When the exhaust flow rate can be prevented from rising excessively. The nozzle cross-sectional area corresponds to the flow channel cross-sectional area of the exhaust gas.

  More specifically, as shown in FIG. 3, in the interior of the turbine casing 60, an annular cavity 60b is provided adjacent to the direction in which the turbine shaft extends with respect to the turbine chamber 60a so as to correspond to the turbine chamber 60a. It is formed. The support shafts 44d of the movable vanes 44c respectively project through the partition between the cavity 60b and the turbine chamber 60a and project into the cavity 60b. The base end of a horseshoe-shaped connecting member 64 is attached to a portion of the support shaft 44d that protrudes into the hollow portion 60b, and one end of the connecting pin 64a is slidably on the distal end side of each connecting member 64. It is attached. Further, the other end of the connection pin 64a is rotatably fixed to a ring member 66 disposed over the entire circumference of the cavity 60b so as to correspond to the movable vane 44c.

  The ring member 66 is connected to the rod 72 of the VGT actuator 70 (FIG. 1) via the link mechanism 68. Specifically, as shown in FIG. 3, the link mechanism 68 has a connecting pin 68a pivotably connected to the ring member 66 at one end, and one end pivotable at the other end of the connecting pin 68a. And a columnar member 68c connected to the other end of the first coupling plate member 68b and penetrating the outer wall of the turbine casing 60, and a turbine casing 60 of the columnar member 68c. It consists of the 2nd connection plate-like member 68d by which one end part was connected to the projection end projected to the outside.

  The other end of the second connection plate member 68d is rotatably connected to the rod 72 of the VGT actuator 70 by a connection pin 68e. Furthermore, by actuation of the VGT actuator 70, the rod 72 operates to be transmitted to the ring member 66 via the link mechanism 68, and the ring member 66 pivots around the axis X of the turbine shaft, whereby the movable vane is moved. Each 44c is synchronously rotated around the support shaft 44d. Therefore, the opening degree of the nozzle 62 is changed by the operation of the rod 72.

Next, control of the engine system 1 by the control device 10 will be described with reference to FIG. 4. FIG. 4 is a block diagram showing each sensor and actuator connected to the control device 10.
The engine system 1 configured as described above is controlled by the control device 10. The control device 10 is configured of a CPU that executes a program, a memory that stores programs and data, a microprocessor having a counter timer group, an interface, and the like. As will be described later, the functions of the racing determination means 10a and the engine control means 10b in the control device 10 are realized by the CPU, program, data and the like built in the control device 10.

  As shown in FIG. 4, various sensors are connected to the control device 10, and detection signals from them are input. The sensors connected include, for example, a vehicle speed sensor 78 for detecting the vehicle speed of the vehicle, an accelerator opening sensor 80 for detecting an amount of depression of an accelerator pedal by the driver of the vehicle (accelerator opening by driver operation) 2, an engine speed sensor 36 for detecting the rotational speed of the engine 2, a supercharging pressure sensor 82 for detecting the supercharging pressure of the intake air after passing through the intercooler 48, and supercharged by the compressor 44a of the turbocharger 44; There is an exhaust pressure sensor 84 that detects the exhaust pressure at the upstream portion, and a nozzle position sensor 86 that detects the position of the rod 72.

  The control device 10 performs various calculations based on these detection signals to determine the state of the engine 2 and the vehicle, and accordingly, various actuators such as the VGT actuator 70 that drive the fuel injection valve 34 and the rod 72. Is configured to output a control signal to the device.

  The control device 10 sets the injection amount of fuel to be injected into the combustion chamber 20 per cycle of the engine 2 based on the torque required by the driver of the vehicle, and from the fuel injection valve 34 by the set fuel injection amount. A signal having a pulse width corresponding to the fuel injection amount is output to the fuel injection valve 34 so that the fuel is injected into the combustion chamber 20. The control device 10 stores in advance a map for determining the fuel injection amount based on the required torque, and when the control device 10 sets the fuel injection amount based on the required torque, the fuel injection amount according to the map Set Further, the required torque is determined based on the detection signals of the vehicle speed sensor 78, the accelerator opening sensor 80, and the engine speed sensor 36. Similarly, the control device 10 is configured to calculate the load amount on the engine 2 based on the detection signal of each sensor, and store it for a predetermined period.

Next, abnormal combustion suppression control in a racing state, which is executed by the control device 10 of the engine 2 according to the first embodiment of the present invention, will be described with reference to FIGS. 5 to 7.
FIG. 5 is a flowchart of abnormal combustion suppression control performed in the racing state. FIG. 6 is a view showing the relationship between the engine speed and the opening degree of the nozzle 62 when the abnormal combustion suppression control is executed. FIG. 7 is a view showing the relationship between the engine speed and the opening degree of the fuel injection amount when the abnormal combustion suppression control is executed. The flowchart shown in FIG. 5 is a subroutine repeatedly executed by the control device 10 while the engine 2 is in operation.

  First, in step S1 of FIG. 5, it is determined whether the transmission of the vehicle is set to the stop range. That is, when the vehicle is an AT (Automatic Transmission) car, when the transmission is set to the neutral range (N range) or the parking range (P range), the transmission of the vehicle is set to the stop range It is judged that When the vehicle is a manual transmission (MT) vehicle, when the transmission is set to the neutral gear, it is determined that the transmission of the vehicle is set to the stop range. Further, in the present embodiment, when the AT car is set to the neutral range or the parking range, and when the MT car is set to the neutral gear, the load of the engine 2 is substantially unloaded. I consider it as.

  If it is determined in step S1 that the transmission is set to the stop range, the process proceeds to step S2. In step S2, it is determined whether the speed of the vehicle is less than a predetermined vehicle speed. In the present embodiment, when the vehicle speed detected by the vehicle speed sensor 78 is less than 2 km / h, which is a predetermined low vehicle speed, it is determined that the vehicle is substantially stopped, and the process proceeds to step S3. Thus, when the load of the engine 2 is substantially unloaded and it can be considered that the vehicle is substantially stopped, the control device 10 determines that the engine 2 is in the racing state. Therefore, an arithmetic circuit such as a CPU or the like built in the control device 10 and a program for operating the same function as a racing determination unit 10a that determines the racing state of the engine 2.

  On the other hand, if it is determined in step S1 that the transmission is not set to the stop range, or if it is determined in step S2 that the speed of the vehicle is not less than the predetermined vehicle speed, the process proceeds to step S9. In these cases, the abnormal combustion suppression control is not executed, and in step S9, the controller 10 controls the VGT actuator 70 based on the engine speed detected by the engine speed sensor 36 and the load of the engine 2. Control.

  Next, in step S10, the control device 10 controls the amount of fuel injection injected from the fuel injection valve 34 based on the engine speed detected by the engine speed sensor 36 and the load of the engine 2. As described above, the control device 10 includes a control map regarding the opening degree of the nozzle 62 of the turbocharger 44, the fuel injection amount, and the like to be set in the state of the vehicle detected by each sensor. The control device 10 refers to this control map, and based on the state of the vehicle detected by each sensor, the VGT actuator 70 and the fuel injection valve are obtained so that the predetermined nozzle 62 opening degree and fuel injection amount can be obtained. Control 34

  On the other hand, when it is determined that the engine 2 is in the racing state, the process proceeds to step S3. In step S3, whether or not the engine speed detected by the engine speed sensor 36 is equal to or higher than a predetermined second speed It is judged. If the engine speed is equal to or greater than the second speed, the process proceeds to step S4, and if the engine speed is less than the second speed, the process proceeds to step S5. In the present embodiment, an engine rotational speed of 2150 rpm is set as the second rotational speed.

  In step S5, the abnormal combustion suppression control is not executed, and the control device 10 controls the VGT actuator 70 according to the engine speed in accordance with the above-described normal map. That is, even in the racing state, when the engine speed is less than the second speed, the risk of abnormal combustion occurring is extremely small, so the abnormal combustion suppression control is not executed and the normal control is executed. .

  On the other hand, when the engine speed is equal to or higher than the second speed, the process proceeds to step S4, and the abnormal combustion suppression control is executed. In step S4, as shown in FIG. 6, the controller 10 controls the VGT actuator 70 such that the nozzle 62 of the turbocharger 44 is fully open. That is, the engine control means 10b realized by the arithmetic circuit such as CPU and the like built in the control device 10 and the program for operating the same, the racing determination means 10a determines the racing state of the engine 2, and the engine speed sensor 36 When the engine speed detected by the engine speed increases to a predetermined second speed lower than the first speed, the movable vanes 44c are controlled to reduce the flow speed of the exhaust flowing into the turbine 44b.

  FIG. 6 is a view showing the opening degree of the nozzle 62 set with respect to the engine rotational speed when the abnormal combustion suppression control is executed, and the control in the present embodiment is shown by a solid line, and the control by the conventional control device is shown. Is shown by a broken line. As shown by the broken line in FIG. 6, in the conventional control device, the opening degree of the turbocharger nozzle gradually increases with the increase in engine speed even after the engine speed exceeds 2150 rpm, and exceeds about 4000 rpm It becomes a fixed value. On the other hand, as shown by the solid line in FIG. 6, the control device 10 in the present embodiment executes the abnormal combustion suppression control when the engine speed is about 2150 rpm or more, and the nozzle 62 of the turbocharger 44 is fully open. The VGT actuator 70 is controlled to be as follows.

  Next, in step S6, it is determined whether the engine rotational speed detected by engine rotational speed sensor 36 is equal to or greater than a predetermined first rotational speed set higher than the second rotational speed. . If the engine rotational speed is equal to or greater than the first rotational speed, the process proceeds to step S7. If the engine rotational speed is less than the first rotational speed, the process proceeds to step S8. In the present embodiment, an engine rotational speed of 2500 rpm is set as the first rotational speed.

  In step S8, the control device 10 controls the fuel injection amount by the fuel injection valve 34 according to the engine speed in accordance with the above-described normal map. That is, even in the racing state, when the engine speed is less than the first speed, the risk of abnormal combustion is small, so the fuel injection amount is controlled based on the normal map.

  On the other hand, when the engine speed is equal to or greater than the first speed, the process proceeds to step S7, and the abnormal combustion suppression control is executed. In step S7, as shown in FIG. 7, the controller 10 controls the fuel injection valve 34 to reduce the fuel injection amount and reduce the output of the engine 2. That is, when the racing determination means 10a determines the racing state of the engine 2 and the engine rotational speed detected by the engine rotational speed sensor 36 becomes equal to or greater than the predetermined first rotational speed, the engine control means 10b operates the engine 2 The supply amount of fuel injected from the fuel injection valve 34 is limited such that the output of

  FIG. 7 is a view showing the fuel injection amount set with respect to the engine rotational speed when the abnormal combustion suppression control is executed, and the control in the present embodiment is indicated by a solid line, and the control by the conventional control device is indicated by a broken line It shows by. As shown by the broken line in FIG. 7, in the conventional control device, the fuel injection amount is gradually reduced after the engine speed exceeds about 2500 rpm. On the other hand, as shown by the solid line in FIG. 7, the control device 10 in this embodiment executes abnormal combustion suppression control to sharply reduce the fuel injection amount when the engine speed increases to about 2500 rpm, and The fuel injection amount is fixed at a rotational speed of 2500 rpm or more. As a result, the output of the engine 2 is rapidly reduced.

  That is, in the racing state (the transmission is set to the stop range and the vehicle stops), when the driver depresses the accelerator pedal, the engine speed rapidly increases. At this time, when the engine rotational speed reaches 2150 rpm, which is the second rotational speed, the nozzle 62 of the turbocharger 44 is fully opened (FIG. 6). When the engine speed is further increased to 2500 rpm which is the first engine speed, the fuel injection amount is rapidly reduced to a constant value (FIG. 7). As described above, in the racing state, when the engine speed increases, the flow velocity of the exhaust flowing into the turbocharger 44 increases excessively, and the supercharging pressure also increases accordingly, and the intake air flowing in the intake passage 38 The flow velocity also rises.

  On the other hand, unburned blowby gas that has leaked from the combustion chamber 20 into the crankcase in the engine 2 is extracted by the gas extraction path 74 and returned to the intake passage 38 via the oil separator 76 (see FIG. 1) . The blowby gas is mixed with engine oil in the crankcase, and engine oil remaining without being separated by the oil separator 76 adheres to the inner wall surface of the intake passage 38. As described above, when the engine speed is increased in the racing state and the flow velocity of the intake air flowing in the intake passage 38 is excessively increased, engine oil adhering to the inner wall surface of the intake passage 38 is drawn into the combustion chamber 20 It becomes easy to be done. When a large amount of engine oil is sucked, abnormal combustion may occur in the combustion chamber 20. In particular, when the engine speed reaches 2500 rpm, which is the first speed, the flow velocity of intake air in the intake passage 38 becomes equal to or higher than the predetermined flow velocity, and intake of engine oil starts to occur, thereby increasing the risk of abnormal combustion.

  Therefore, when the engine speed increases in the racing state, the control device 10 according to the present embodiment controls the VGT actuator 70 to control the movable vanes 44c of the turbocharger 44 in the opening direction. As a result, the nozzle 62 is fully opened, the flow velocity of the exhaust blown to the turbine 44 b of the turbocharger 44 is reduced, and an excessive increase in the supercharging pressure by the compressor 44 a directly coupled to the turbine 44 b is suppressed. Furthermore, when the engine speed reaches 2500 rpm, which is the first engine speed, in the racing state, intake of engine oil is likely to occur. Therefore, the control device 10 sharply reduces the fuel injection amount to output the engine power. The flow rate of the intake air in the intake passage 38 is reduced. This suppresses the occurrence of abnormal combustion due to intake of engine oil.

  Here, suction of the engine oil is likely to occur at engine rotational speed of 2500 rpm or more, but the control device 10 controls the VGT actuator 70 when the engine rotational speed rises to 2150 rpm, which is the second rotational speed. Then, the movable vanes 44c are rotated in the opening direction. That is, although the VGT actuator 70 and the movable vanes 44c operate mechanically, the response delay becomes relatively large, but in order to cope with this delay, the control device 10 is operated from the engine speed lower than 2500 rpm for the VGT. The actuation of the actuator 70 is started. As described above, even if the movable vane 44c has a response delay, the control for moving the movable vane 44c in the opening direction is started before the engine speed reaches 2500 rpm, which is the first rotational speed. By the time the engine speed reaches 2500 rpm, the nozzle 62 can be fully opened, and the flow speed of the exhaust blown to the turbine 44b can be reduced.

  Further, when the engine speed reaches 2500 rpm, which is the first speed, the control device 10 reduces the fuel injection amount and reduces the output of the engine 2. Therefore, even if the movable vane 44 has a defect such as sticking, and the opening degree of the nozzle 62 can not be increased, generation of abnormal combustion due to intake of engine oil can be sufficiently suppressed. Furthermore, in the present embodiment, the control device 10 does not execute the abnormal combustion suppression control at an engine rotation speed equal to or lower than the first rotation speed, so the engine rotation speed increases promptly in response to the depression of the accelerator pedal in the racing state. . Therefore, good racing performance can be obtained while suppressing the occurrence of abnormal combustion.

  According to the engine control device 10 of the first embodiment of the present invention, the engine control means 10b reduces the output of the engine 2 when the engine 2 is in the racing state and reaches a predetermined first rotation speed or more. In the state, the occurrence of abnormal combustion in the combustion chamber 20 of the engine 2 can be suppressed. Further, even in the racing state, the engine control means 10b does not reduce the output of the engine 2 until the number of revolutions of the engine 2 reaches the first number of revolutions, so the number of revolutions of the engine 2 becomes faster as the accelerator pedal is depressed. You can get enough racing performance.

  Further, according to the engine control device 10 of the present embodiment, when the engine 2 is in the racing state and the engine speed is increased to the predetermined second speed, the movable vanes 44c are controlled to flow into the turbine 44b. Therefore, the rotational speed of the turbine 44 b may be excessively increased, and the supercharging pressure may be suppressed from being excessively increased. In addition, since the second rotation speed (= 2150 rpm) is set to an engine rotation speed lower than the first rotation speed (= 2500 rpm), the response delay to the operation of the movable vane 44 c at the time of the rapid increase of the engine rotation speed Even when the engine speed is lower than the first speed, the flow speed of the exhaust flowing into the turbine 44b can be reduced until the engine speed reaches the first speed. This makes it possible to reduce the flow speed of the exhaust before the engine speed reaches the first speed, and to prevent an excessive increase in the supercharging pressure.

  Furthermore, according to the engine control device 10 of the present embodiment, the first rotational speed for reducing the output of the engine 2 is set to the rotational speed at which the intake of oil into the combustion chamber 20 starts to occur. It is possible to reliably suppress abnormal combustion that occurs when oil is rapidly drawn into the engine.

  Further, according to the engine control device 10 of the present embodiment, the first rotation number for reducing the output of the engine 2 is set to the rotation number at which the flow velocity of the intake air in the intake passage 38 of the engine 2 is equal to or higher than the predetermined flow velocity. Because of this, it is possible to reliably suppress abnormal combustion that occurs when oil is rapidly sucked into the engine 2.

  Next, with reference to FIG. 8, a control device for an engine according to a second embodiment of the present invention will be described. The engine control apparatus according to the present embodiment differs from the first embodiment in the flowchart of the abnormal combustion suppression control described above. Therefore, only the parts of the second embodiment of the present invention that are different from the first embodiment will be described here, and the description of the same configuration, operation, and effects will be omitted.

  In the first embodiment described above, the abnormal combustion suppression control is always executed when the engine speed becomes equal to or higher than the first speed. On the other hand, in the engine control device according to the present embodiment, the abnormal combustion suppression control is executed only when a large amount of engine oil adheres in the intake passage and the engine rotational speed increases in a state in which abnormal combustion tends to occur. .

  First, in step S21 of FIG. 8, it is determined whether the transmission of the vehicle is set to the stop range. If it is determined in step S21 that the transmission is set to the stop range, the process proceeds to step S22. In step S22, it is determined whether the speed of the vehicle is less than a predetermined vehicle speed. Also in the present embodiment, when the vehicle speed is less than 2 km / h, it is determined that the vehicle is substantially stopped, and the process proceeds to step S23.

  On the other hand, if it is determined in step S21 that the transmission is not set to the stop range, or if it is determined in step S22 that the speed of the vehicle is not less than the predetermined vehicle speed, the process proceeds to step S33. In these cases, the abnormal combustion suppression control is not executed, and in step S33, integration of the time during which the engine 2 is operated at light load is performed. That is, during operation of the engine 2, the blowby gas leaking from the combustion chamber 20 into the crankcase is returned to the intake passage 38 through the gas extraction passage 74 via the oil separator 76. The blowby gas thus recirculated contains engine oil remaining without being removed by the oil separator 76.

  Here, when the engine 2 is operated at high load and medium load, the flow rate of air flowing through the intake passage 38 is relatively large, so engine oil mixed in with the blowby gas flowing into the intake passage 38 Flows into the combustion chamber 20 without accumulating in the intake passage 38. On the other hand, when the engine 2 is operated at a light load, the flow rate of the air flowing through the intake passage 38 is small, so the engine oil mixed in the blowby gas remains in the intake passage 38 and It easily adheres to the wall surface. Therefore, after the engine 2 has been operated for a long time with a light load, a large amount of engine oil is likely to be attached to the inner wall surface of the intake passage 38. In such a state, when the engine speed rapidly increases and the flow rate of air flowing through the intake passage 38 rapidly increases, the engine oil adhering to the inner wall surface intrudes into the combustion chamber 20 at one time, resulting in abnormal combustion. Results.

  For this reason, in the present embodiment, in step S33, the time during which the engine 2 was operated at light load is integrated, and the amount of engine oil deposited in the intake passage 38 is estimated based on this. Therefore, the integration of the light load operating time executed by the arithmetic circuit such as the CPU built in the control device and the program for operating the same functions as the adhering oil amount estimating means. As a modification, the present invention can also be configured to estimate the amount of engine oil adhering to the intake passage based on the frequency at which the engine 2 is operated at light load.

  Next, in step S34, the control device controls the VGT actuator 70 based on the engine speed detected by the engine speed sensor 36 and the load of the engine 2.

  Furthermore, in step S35, the control device controls the fuel injection amount injected from the fuel injection valve 34 based on the engine speed detected by the engine speed sensor 36 and the load of the engine 2. That is, the control device refers to the normal control map, and based on the state of the vehicle detected by each sensor, the VGT actuator 70 and the fuel can be obtained so as to obtain a predetermined nozzle 62 opening and fuel injection amount. The injection valve 34 is controlled.

  On the other hand, if it is determined in step S22 that the vehicle speed is less than the predetermined vehicle speed, that is, if it is determined that the engine 2 is in the racing state, the process proceeds from step S22 to step S23. In step S23, it is determined whether the light load operation time integrated in step S33 is equal to or longer than a predetermined time. If the light load operation time is equal to or longer than the predetermined time, the process proceeds to step S26. If the light load operation time is less than the predetermined time, the process proceeds to step S24.

  In step S24, as in step S34 described above, the control device controls VGT actuator 70 according to the normal control map based on the engine speed detected by engine speed sensor 36 and the load on engine 2. Do. Next, in step S25, the control device controls the fuel injection valve 34 according to the normal control map based on the engine speed detected by the engine speed sensor 36 and the load of the engine 2 as in step S35 described above. Control the amount of fuel injected from the

  That is, when it is determined in step S23 that the light load operation time of the engine 2 is less than the predetermined time, it is estimated that the amount of engine oil adhering to the intake passage 38 is small and less than the predetermined amount. Be done. Therefore, even if the engine 2 is in the racing state, the possibility of abnormal combustion being generated is extremely small, the abnormal combustion suppression control in step S26 and subsequent steps is not executed, and the control is executed according to the normal control map.

  That is, in the engine control means provided in the control device, the racing determination means determines the racing state of the engine, and the engine rotational speed detected by the engine rotational speed sensor 36 becomes equal to or greater than the first rotational speed. Even if the amount of engine oil adhering to the inside of the intake passage 38 is determined to be equal to or less than the predetermined amount by the adhering oil amount estimating means, the output reduction of the engine 2 is not performed. As described above, in the control system of the engine of the present embodiment, the abnormal combustion suppression control is not executed when there is no risk of causing the abnormal combustion even if the engine 2 is in the racing state. Therefore, when the driver depresses the accelerator pedal, the engine speed can be rapidly increased to a high speed, and the racing performance can be further improved.

On the other hand, if it is determined in step S23 that the time during which the engine 2 is in a light load operation is determined to be equal to or longer than the predetermined time, the process proceeds to step S26, and abnormal combustion suppression control is executed by the processing of step S26 and subsequent steps. . The processes in steps S26 to S31 in FIG. 8 are the same as the processes in steps S3 to S8 in FIG.
Further, in the present embodiment, in step S32 after the abnormal combustion suppression control to reduce the fuel injection amount is performed in step S30 of FIG. 8, the integration time of the light load operation integrated in step S33 described above It is reset.

  According to the engine control device of the second embodiment of the present invention, the adhering oil amount estimating means estimates the amount of engine oil adhering to the inside of the intake passage 38, and the amount of engine oil is less than a predetermined amount In this case, the output of the engine 2 is not reduced. For this reason, the amount of engine oil attached is small, and the output of the engine 2 is not reduced in a state where abnormal combustion is unlikely to occur, and racing performance can be further improved.

  According to the engine control device of the present embodiment, the adhering oil amount estimating means estimates the adhesion of the engine oil based on the time when the engine 2 is operated at light load or the frequency at which the engine is operated at light load Therefore, the state where abnormal combustion is likely to occur can be reliably detected, and racing performance can be improved while reliably suppressing the occurrence of abnormal combustion.

  Although the preferred embodiments of the present invention have been described above, various modifications can be added to the above-described embodiments. In particular, although the present invention is applied to a diesel engine in the embodiment described above, the present invention can be applied to any type of engine, such as a gasoline engine.

Reference Signs List 1 engine system 2 engine 4 intake system 6 fuel supply system 8 exhaust system 10 control device 12 cylinder block 12a cylinder 14 cylinder head 16 oil pan 18 piston 20 combustion chamber 22 connecting rod 24 crankshaft 26 intake port 28 exhaust port 30 intake valve 32 exhaust Valve 34 Fuel injection valve 36 Engine speed sensor 38 Intake passage 40 Air cleaner 42 Surge tank 44 Turbo supercharger (variable displacement supercharger)
44a compressor 44b turbine (exhaust turbine)
44c Movable vane (movable member)
44d Support shaft 46 Intake shutter valve 48 Intercooler 50 Fuel tank 52 Fuel supply passage 54 Fuel pump 56 Exhaust passage 58 High pressure EGR device 58a High pressure EGR passage 58b High pressure EGR valve 60 Turbine casing 60a Turbine chamber 60b Cavity 62 Nozzle 64 Connection member 64a Connection Pin 66 Ring member 68 Link mechanism 68a Connection pin 68b First connection plate member 68c Column-shaped member 68d Second connection plate member 68e Connection pin 70 Actuator for VGT 72 Rod 74 Gas extraction path 76 Oil separator 78 Vehicle speed sensor 80 Accelerator opening degree sensor 82 Supercharging pressure sensor 84 Exhaust pressure sensor 86 Nozzle position sensor

Claims (5)

A control device of an engine provided with a variable displacement turbocharger capable of changing the amount of exhaust gas flowing into an exhaust turbine,
The variable displacement turbocharger has movable vanes for changing the flow velocity of the exhaust flowing into the exhaust turbine,
further,
Racing determination means for determining a racing state in which the vehicle is substantially stopped and the load on the engine is substantially unloaded;
A rotation speed sensor for detecting the rotation speed of the engine;
The racing determination means determines the racing state of the engine, and when the rotational speed detected by the rotational speed sensor becomes equal to or higher than a predetermined first rotational speed, the output of the engine is reduced. Engine control means for controlling;
I have a,
When the racing determination means determines the racing state of the engine and the engine speed detected by the engine speed sensor rises to a predetermined second engine speed lower than the first engine speed, Controlling the movable vanes to reduce the flow velocity of the exhaust flowing into the exhaust turbine;
Furthermore, when the racing determination means determines the racing state of the engine and the rotational speed detected by the rotational speed sensor rises to the first rotational speed, the engine control means determines from the fuel injection valve of the engine A control device for an engine, characterized in that the output of the engine is reduced by limiting the amount of fuel to be injected . The engine control device according to claim 1, wherein the first rotation speed is set to a rotation speed at which the suction of the oil adhering to the inside of the intake passage of the engine into the combustion chamber starts to occur. The engine control device according to claim 1, wherein the first rotation speed is set to a rotation speed at which a flow velocity of intake air in an intake passage of the engine is equal to or higher than a predetermined flow velocity. Further, it has an attached oil amount estimation means for estimating the amount of oil adhering to the intake passage of the engine,
In the engine control means, the adhesion oil is detected even when the racing determination means determines the racing state of the engine and the rotational speed detected by the rotational speed sensor becomes the first rotational speed or more. depending on the amount estimating means, when the amount of oil adhering to the intake passage is determined to be equal to or less than the predetermined amount, to any one of claims 1 to 3 do not perform the output reduction of said engine The control device of the described engine. The adhering oil amount estimating means determines that the amount of oil adhering to the intake passage is less than or equal to a predetermined amount based on the time when the engine is operated at light load or the frequency at which the engine is operated at light load. The control device of the engine according to claim 4, wherein it is determined whether or not.

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