JP2018071379A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device capable of appropriately executing the switch of an operation mode between a reduced cylinder operation mode and an all cylinder operation mode while considering an intake temperature.SOLUTION: The engine control device includes an engine 10 including a plurality of cylinders 2 and adapted to be operated while switching between the reduced cylinder operation mode in which combustion is suspended in the cylinder 2 as part of the plurality of cylinders 2 and the all cylinder operation mode in which combustion is performed in all of the plurality of cylinders 2, and a PCM 50 for allowing the engine 10 to be operated in the reduced cylinder operation mode when the torque of the engine 10 is not higher than a predefined determination value. The PCM 50 acquires an intake temperature (equivalent to an intake temperature relative value) for the engine 10 and sets the determination value according to the acquired intake temperature.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an engine control device, and more particularly to an engine control device that can be operated by switching between a reduced-cylinder operation mode and an all-cylinder operation mode.

  Conventionally, the engine is operated by switching between a reduced-cylinder operation mode in which combustion of some of the cylinders is stopped and an all-cylinder operation mode in which combustion is performed in all of the plurality of cylinders according to the operating state of the engine. The technique to make is proposed (for example, refer patent document 1). In particular, Patent Document 1 discloses an engine that changes the determination threshold used for determining the engine load in order to switch between the reduced-cylinder operation mode and the all-cylinder operation mode according to the atmospheric pressure, that is, an engine that performs the reduced-cylinder operation mode. A technique for changing the operating range is disclosed. In this technique, even when the atmospheric pressure changes, switching between the reduced-cylinder operation mode and the all-cylinder operation mode can be appropriately performed, and the engine output is increased almost linearly with respect to the accelerator operation.

JP 2004-316552 A

  Incidentally, the charging efficiency (air filling amount) of fresh air into the cylinder changes according to the intake air temperature of the engine. Specifically, the air filling amount tends to decrease as the intake air temperature increases, and the air filling amount tends to increase as the intake air temperature decreases. Therefore, the engine torque tends to change according to the intake air temperature. Therefore, the following problems may occur if the engine operating region (reducing cylinder operating region) for performing the above-described reduced cylinder operating mode is not set in consideration of the intake air temperature. That is, for example, when the reduced-cylinder operation mode is performed when the intake air temperature is relatively high (in this case, the air filling amount tends to decrease and the engine torque tends to decrease), the high-load side of the reduced-cylinder operation region The engine torque does not increase properly in response to the driver's accelerator depressing operation, which may cause the driver to feel uncomfortable.

  The present invention has been made to solve the above-described problems of the prior art, and appropriately switches the operation mode between the reduced-cylinder operation mode and the all-cylinder operation mode in consideration of the intake air temperature. An object of the present invention is to provide an engine control device that can be executed.

In order to achieve the above object, the present invention includes a plurality of cylinders, a reduced-cylinder operation mode in which combustion of some of the plurality of cylinders is stopped, and all-cylinder operation in which combustion is performed in all of the plurality of cylinders. An engine that can be operated by switching modes, and a control means that causes the engine to operate in a reduced-cylinder operation mode when an engine torque-related value related to the engine torque is equal to or less than a predetermined determination value. The apparatus further comprises an acquisition means for acquiring an intake air temperature related value related to the intake air temperature of the engine, and the control means sets a determination value in accordance with the acquired intake air temperature related value. To do.
According to the present invention configured as described above, the determination value for determining the engine torque related value in the switching of the operation mode between the reduced cylinder operation mode and the all cylinder operation mode is changed according to the intake air temperature related value degree. Let Thereby, switching of the operation mode between the reduced-cylinder operation mode and the all-cylinder operation mode can be appropriately executed according to the intake air temperature. Therefore, even if the intake air temperature changes in the reduced-cylinder operation mode, the engine torque can be appropriately increased in accordance with the driver's accelerator depressing operation, and the uncomfortable feeling given to the driver can be suppressed. For example, when the intake air temperature is relatively high, it is possible to suppress the occurrence of the problem that the engine torque does not increase appropriately on the high load side in the reduced-cylinder operation region.

In the present invention, preferably, the control means obtains the maximum air filling amount of the cylinder combusting in the reduced-cylinder operation mode based on the intake air temperature related value, and sets the determination value according to the maximum air filling amount.
According to the present invention configured as described above, the maximum air filling amount that can be filled in the cylinder of the engine is obtained based on the intake air temperature related value, and the determination value is set based on the maximum air filling amount. Thereby, it is possible to set a determination value that appropriately takes into account the maximum air filling amount that changes in accordance with the intake air temperature.

In the present invention, preferably, the control means obtains a generated torque value of the engine when operating at the stoichiometric air-fuel ratio at the maximum air charge amount, and sets a determination value according to the generated torque value.
According to the present invention configured as described above, the determination value is set according to the engine torque output when the engine is operated at the stoichiometric air-fuel ratio by applying the maximum air filling amount. As a result, the determination value can be set by appropriately taking into account the engine torque corresponding to the maximum air filling amount that varies depending on the intake air temperature.

In this invention, Preferably, it further has an atmospheric pressure acquisition means for acquiring the atmospheric pressure, and the control means sets a determination value according to the atmospheric pressure in addition to the intake air temperature related value.
According to the present invention configured as described above, since the determination value is set according to the atmospheric pressure in addition to the intake air temperature related value, the determination is performed by appropriately taking into consideration the intake air temperature and the intake air density corresponding to the atmospheric pressure. A value can be set.

In another aspect, in order to achieve the above object, the present invention includes a plurality of cylinders, a reduced-cylinder operation mode in which combustion of some of the cylinders is stopped, and combustion in all of the plurality of cylinders. And an all-cylinder operation mode that can be operated by switching between all-cylinder operation modes, and has an acquisition unit that acquires an intake air temperature related value related to an intake air temperature of the engine, and the control device acquires the acquired intake air temperature It is characterized by having a reduced-cylinder operation region setting means for setting the operation region in the reduced-cylinder operation mode according to the related value.
According to the present invention configured as described above, since the reduced-cylinder operation region is set according to the intake-air temperature related value, even if the intake air temperature changes in the reduced-cylinder operation mode, the engine is operated according to the driver's accelerator depression operation. The torque can be increased appropriately, and the uncomfortable feeling given to the driver can be suppressed.

In the present invention described above, preferably, the operation region of the reduced cylinder operation mode is defined based on an engine torque related value related to the engine torque and an engine speed related value related to the engine speed. The cylinder operation region setting means sets an upper limit value of the operation region in the reduced cylinder operation mode defined by the engine torque related value according to the intake air temperature related value.
According to the present invention configured as described above, by setting the upper limit value of the reduced-cylinder operation region defined by the engine torque-related value based on the intake air temperature-related value, using such a reduced-cylinder operation region, Switching between the reduced-cylinder operation mode and the all-cylinder operation mode can be appropriately performed according to the intake air temperature.

In still another aspect, in order to achieve the above object, the present invention includes a plurality of cylinders, a reduced-cylinder operation mode in which combustion of some of the plurality of cylinders is stopped, and all of the plurality of cylinders. An engine control apparatus that can be operated by switching to an all-cylinder operation mode in which combustion is performed, and has an acquisition unit that acquires an intake air temperature related value related to the intake air temperature of the engine. With respect to the related engine torque related value, the engine has an upper limit setting means for setting an upper limit value of the engine torque related value that can be operated in the reduced-cylinder operation mode. In the case of the first temperature, the upper limit value is set higher than in the case where the acquired intake air temperature related value is the second temperature higher than the first temperature.
According to the present invention thus configured, when the intake air temperature related value is low, the upper limit value of the engine torque related value that can be operated in the reduced cylinder operation mode is made higher than when the intake air temperature related value is high. As a result, even if the intake air temperature changes in the reduced-cylinder operation mode, the engine torque can be appropriately increased according to the driver's accelerator depressing operation, and the uncomfortable feeling given to the driver can be suppressed.

  According to the engine control apparatus of the present invention, it is possible to appropriately execute the operation mode switching between the reduced-cylinder operation mode and the all-cylinder operation mode in consideration of the intake air temperature.

1 is a schematic configuration diagram of an engine system to which an engine control device according to an embodiment of the present invention is applied. 1 is a schematic plan view of an engine according to an embodiment of the present invention. It is a block diagram which shows the electric constitution of the control apparatus of the engine by embodiment of this invention. It is the map which showed notionally the operation area | region of the engine which switches an operation mode in embodiment of this invention. It is explanatory drawing about the basic concept of the content of control by embodiment of this invention. It is a flowchart which shows the operation mode switching process by embodiment of this invention.

  Hereinafter, an engine control apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  <System configuration>

  First, an engine system to which an engine control apparatus according to an embodiment of the present invention is applied will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of an engine system to which an engine control apparatus according to an embodiment of the present invention is applied. FIG. 2 is a schematic plan view of an engine according to an embodiment of the present invention. FIG. 3 is a block diagram showing an electrical configuration of the engine control apparatus according to the embodiment of the present invention.

  As shown in FIGS. 1 and 3, the engine system 100 mainly includes an intake passage 1 through which intake air (air) introduced from the outside passes, intake air supplied from the intake passage 1, and fuel injection described later. An engine 10 (specifically, a gasoline engine) that generates fuel for the vehicle by burning an air-fuel mixture supplied from the valve 13 and an exhaust passage 25 that discharges exhaust gas generated by combustion in the engine 10. And sensors 30 to 39 for detecting various states related to the engine system 100, and a PCM (Power-train Control Module) 50 for controlling the entire engine system 100.

  In the intake passage 1, in order from the upstream side, an air cleaner 3 for purifying intake air introduced from the outside, a throttle valve 5 for adjusting the amount of intake air (intake air amount) passing through, and the intake air supplied to the engine 10 temporarily. And a surge tank 7 for storing automatically.

As shown in FIG. 2, the engine 10 according to the present embodiment is an in-line four-cylinder engine including four cylinders 2 (2A to 2D) arranged in a straight line. The engine 10 mainly includes an intake valve 12 that introduces intake air supplied from the intake passage 1 into the combustion chamber 11, a fuel injection valve 13 that injects fuel toward the combustion chamber 11, and a combustion chamber 11. A spark plug 14 that ignites the supplied air-fuel mixture, a piston 15 that reciprocates by combustion of the air-fuel mixture in the combustion chamber 11, a crankshaft 16 that is rotated by the reciprocating motion of the piston 15, And an exhaust valve 17 that exhausts exhaust gas generated by combustion of the air-fuel mixture in the combustion chamber 11 to the exhaust passage 25.
The pistons 15 provided in the cylinders 2A to 2D reciprocate with a phase difference of 180 ° (180 ° CA) at the crank angle. Correspondingly, the ignition timing in each of the cylinders 2A to 2D is set to a timing shifted in phase by 180 ° CA.

The engine 10 according to the present embodiment is a cylinder deactivation engine capable of an operation mode in which two of the four cylinders 2A to 2D are deactivated and the remaining two cylinders are operated, that is, a reduced cylinder operation mode.
Specifically, in order from the left side of FIG. 2, assuming that the cylinder 2A is the first cylinder, the cylinder 2B is the second cylinder, the cylinder 2C is the third cylinder, and the cylinder 2D is the fourth cylinder, all of the four cylinders 2A to 2D In the all-cylinder operation mode in which is operated, ignition is performed in the order of the first cylinder 2A → the third cylinder 2C → the fourth cylinder 2D → the second cylinder 2B.
In the reduced-cylinder operation mode, the ignition operation of the spark plug 14 and the fuel injection from the fuel injection valve 13 are prohibited in two cylinders (first cylinder 2A and fourth cylinder 2D in the present embodiment) whose ignition order is not continuous. In the remaining two cylinders (that is, the third cylinder 2C and the second cylinder 2B), ignition and combustion are alternately performed.

  In addition, the engine 10 has variable intake valve mechanisms 18 and variable exhaust valve mechanisms in which the operation timings (corresponding to valve phases) of the intake valve 12 and the exhaust valve 17 are variable valve timing mechanisms. 19 is variably configured. As the variable intake valve mechanism 18 and the variable exhaust valve mechanism 19, various known types can be applied. For example, the operation of the intake valve 12 and the exhaust valve 17 is performed using a mechanism configured in an electromagnetic or hydraulic manner. Timing can be changed.

  Further, the engine 10 has a valve stop mechanism 20 that stops the opening and closing operations of the intake valve 12 and the exhaust valve 17 of the first cylinder 2A and the fourth cylinder 2D in the reduced cylinder operation mode. The valve stop mechanism 20 includes, for example, a so-called lost motion mechanism that is interposed between the cam and the valve and that enables or disables transmission of the cam driving force to the valve. Alternatively, the valve stop mechanism 20 includes two types of cams having different cam profiles, a first cam having a cam crest for opening and closing the valve, and a second cam for stopping the valve opening and closing operation, and the first cam A so-called cam shifting mechanism that selectively transmits an operating state of one of the second cams to the valve may be included.

  The exhaust passage 25 is mainly provided with exhaust purification catalysts 26a and 26b having an exhaust gas purification function, such as a NOx catalyst, a three-way catalyst, and an oxidation catalyst. Hereinafter, when the exhaust purification catalysts 26a and 26b are used without distinction, they may be simply referred to as “exhaust purification catalyst 26”.

  Further, the engine system 100 is provided with sensors 30 to 39 that detect various states relating to the engine system 100. Specifically, these sensors 30 to 39 are as follows. The accelerator opening sensor 30 detects an accelerator opening that is an accelerator pedal opening (corresponding to an amount by which the driver has depressed the accelerator pedal). The air flow sensor 31 detects an intake air amount corresponding to the flow rate of the intake air passing through the intake passage 1. The throttle opening sensor 32 detects the throttle opening that is the opening of the throttle valve 5. The intake air temperature sensor 33 detects the temperature of intake air (intake air temperature) supplied to the engine 10. The crank angle sensor 34 detects the crank angle in the crankshaft 16. The water temperature sensor 35 detects the water temperature that is the temperature of the cooling water that cools the engine 10. The temperature sensor 36 detects an in-cylinder temperature that is a temperature in the cylinder 2 of the engine 10. The cam angle sensors 37 and 38 detect operation timings including the closing timings of the intake valve 12 and the exhaust valve 17, respectively. The atmospheric pressure sensor 39 detects atmospheric pressure. These various sensors 30 to 39 output detection signals S130 to S139 corresponding to the detected parameters to the PCM 50, respectively.

  The PCM 50 controls the components in the engine system 100 based on the detection signals S130 to S139 input from the various sensors 30 to 39 described above. Specifically, as shown in FIG. 3, the PCM 50 supplies a control signal S105 to the throttle valve 5, controls the opening / closing timing and throttle opening of the throttle valve 5, and sends a control signal S113 to the fuel injection valve 13. Then, the fuel injection amount and the fuel injection timing are controlled, the control signal S114 is supplied to the spark plug 14, the ignition timing is controlled, and the control signal S118 is supplied to each of the variable intake valve mechanism 18 and the variable exhaust valve mechanism 19. , S119 is supplied to control the operation timing of the intake valve 12 and the exhaust valve 17, and the control signal S120 is supplied to the valve stop mechanism 20 to supply the intake valve 12 and the exhaust valve of the first cylinder 2A and the fourth cylinder 2D. The stop / operation of the opening / closing operation 17 is controlled.

  In particular, in the present embodiment, the PCM 50 performs control for switching the operation mode of the engine 10 between the reduced-cylinder operation mode and the all-cylinder operation mode based on the operation state of the engine 10. Here, with reference to FIG. 4, the operation area | region which performs each of the reduced-cylinder operation mode and all-cylinder operation mode in embodiment of this invention is demonstrated. FIG. 4 is a map conceptually showing an operation region of the engine for switching the operation mode in the embodiment of the present invention. FIG. 4 shows the engine speed on the horizontal axis and the engine torque on the vertical axis.

  As shown in FIG. 4, a reduced-cylinder operation region for performing the reduced-cylinder operation mode is set in a range where the engine speed is relatively low and the engine torque is low. An all-cylinder operation region for performing the cylinder operation mode is set. The PCM 50 refers to such a map to determine whether the engine speed and the engine torque are included in the reduced-cylinder operation region or the all-cylinder operation region, and according to the determination result, the reduced-cylinder operation mode and The valve stop mechanism 20 controls the stop / operation of the opening / closing operations of the intake valve 12 and the exhaust valve 17 of the first cylinder 2A and the fourth cylinder 2D so as to execute any one of the all-cylinder operation modes. In addition, the PCM 50 controls execution / non-execution of ignition of the spark plug 14 and fuel injection of the fuel injection valve 13 for the first cylinder 2A and the fourth cylinder 2D.

  Such a PCM 50 includes a CPU (Central Processing Unit) and various programs interpreted and executed on the CPU (including a basic control program such as an OS and an application program that is activated on the OS and realizes a specific function). And a computer having an internal memory such as a ROM or RAM for storing programs and various data. Further, the PCM 50 is configured to function as “control means”, “acquisition means”, “reduced cylinder operation region setting means”, and “upper limit value setting means” in the present invention.

<Control contents according to this embodiment>
Next, specific control contents performed by the PCM 50 in the embodiment of the present invention will be described.

  First, a basic concept of control contents according to the embodiment of the present invention will be described with reference to FIG. FIG. 5 is a map similar to FIG. 4 showing the reduced-cylinder operation region and the all-cylinder operation region defined by the engine speed (horizontal axis) and the engine torque (vertical axis).

  In the present embodiment, the PCM 50 changes the reduced-cylinder operation region as indicated by arrows A1 and A2 according to the intake air temperature detected by the intake air temperature sensor 33. Specifically, the PCM 50 changes the upper limit value of the reduced cylinder operation region defined by the engine torque (corresponding to the upper limit value of the engine torque that can be operated in the reduced cylinder operation mode) according to the intake air temperature. Since the reduced cylinder operation mode is executed when the engine torque is equal to or lower than the upper limit value of the reduced cylinder operation region defined by the engine torque, the value is used to determine the engine torque when the operation mode is switched. Since it corresponds to the determination value, changing the upper limit value as described above corresponds to changing the determination value.

  More specifically, the PCM 50 increases the upper limit value of the engine torque in the reduced-cylinder operation region when the intake air temperature is low than when the intake air temperature is high (see arrow A1), and when the intake air temperature is high, The upper limit value of the engine torque in the reduced cylinder operation region is made smaller than when the intake air temperature is low (see arrow A2). Typically, the PCM 50 increases the upper limit value of the engine torque in the reduced-cylinder operation region as the intake air temperature becomes lower (see arrow A1), and increases the upper limit value of the engine torque in the reduced-cylinder operation region as the intake air temperature becomes higher. Decrease (see arrow A2).

The reason why the upper limit value of the reduced-cylinder operation region is set according to the intake air temperature is as follows. In accordance with the intake air temperature of the engine 10, the density of intake air introduced into the cylinder 2 (intake density) changes, and the efficiency of charging fresh air into the cylinder 2 (air charge amount) changes. Specifically, when the intake air temperature increases, the intake air density decreases and the air filling amount decreases, and when the intake air temperature decreases, the intake air density increases and the air filling amount tends to increase. Therefore, the engine torque tends to change according to the intake air temperature.
Therefore, if the reduced cylinder operating region is not set in consideration of the intake air temperature, the following problem may occur. That is, for example, when the reduced-cylinder operation mode is performed when the intake air temperature is relatively high (in this case, the air filling amount tends to decrease and the engine torque tends to decrease), the high-load side of the reduced-cylinder operation region The engine torque does not increase properly in response to the driver's accelerator depressing operation, which may cause the driver to feel uncomfortable.
In order to solve such a problem, in the present embodiment, the PCM 50 changes the reduced-cylinder operation region according to the intake air temperature, that is, changes the upper limit value of the engine torque in the reduced-cylinder operation region according to the intake air temperature. In this way, even when the intake air temperature changes, for example, on the high load side of the reduced-cylinder operation region, the engine torque is appropriately increased with respect to the driver's accelerator depressing operation and given to the driver. I try to suppress the sense of incongruity.

  Furthermore, in this embodiment, the PCM 50 changes the reduced-cylinder operation region in consideration of the atmospheric pressure detected by the atmospheric pressure sensor 39 in addition to the intake air temperature as described above. Specifically, the PCM 50 increases the upper limit value of the engine torque in the reduced-cylinder operation region as the atmospheric pressure increases (see arrow A1 in FIG. 5), and the engine torque in the reduced-cylinder operation region decreases as the atmospheric pressure decreases. The upper limit value is decreased (see arrow A2 in FIG. 5). The reason for this is the same as described for the intake air temperature. That is, the intake air density changes according to the atmospheric pressure, and the air charge amount of the engine 10 changes.

  Next, referring to FIG. 6, in the embodiment of the present invention, a process for setting a reduced-cylinder operation region according to various state values and switching the operation mode based on the reduced-cylinder operation region is specifically described. explain. FIG. 6 is a flowchart showing an operation mode switching process according to the embodiment of the present invention.

  First, in step S <b> 1, the PCM 50 acquires the atmospheric pressure detected by the atmospheric pressure sensor 39. In step S <b> 2, the PCM 50 acquires the intake air temperature detected by the intake air temperature sensor 33.

  Next, in step S3, the PCM 50 determines the maximum air filling amount (maximum filling amount / maximum air filling) that can be filled in the cylinder 2 of the engine 10 based on the atmospheric pressure acquired in step S1 and the intake air temperature acquired in step S2. Amount). In one example, the PCM 50 obtains the maximum filling amount corresponding to the current atmospheric pressure and the intake air temperature with reference to a map (three-dimensional map) in which the maximum filling amount corresponding to the atmospheric pressure and the intake air temperature is associated. To do. In another example, the PCM 50 calculates the maximum filling amount from the current atmospheric pressure and intake air temperature using a predetermined model or a predetermined arithmetic expression. Basically, the maximum filling amount tends to increase as the intake air temperature decreases and the atmospheric pressure increases. Conversely, the maximum charging amount decreases as the intake air temperature increases and the atmospheric pressure decreases. Become a trend.

  Next, in step S4, the PCM 50 calculates the engine torque that is output when the engine 10 is operated at the stoichiometric air-fuel ratio by applying the maximum filling amount obtained in step S3. In one example, the PCM 50 calculates this engine torque using a predetermined combustion model or the like. Basically, the calculated engine torque tends to increase as the maximum filling amount increases, and conversely, the calculated engine torque tends to decrease as the maximum filling amount decreases.

  Next, in step S5, the PCM 50 sets a reduced-cylinder operation region based on the engine torque calculated in step S4. Specifically, the PCM 50 sets the calculated engine torque as the upper limit value of the engine torque in the reduced cylinder operation region.

  Next, in step S6, the PCM 50 determines whether or not the current operation state of the engine 10 is included in the reduced-cylinder operation region set in step S5. Specifically, the PCM 50 uses the reduced-cylinder operation region set in step S5, and the current engine speed and the engine torque are respectively determined based on the engine speed range and the engine specified by the reduced-cylinder operation region. It is determined whether or not it is included in the torque range.

  As a result of the determination in step S6, when it is determined that the current engine speed and engine torque are included in the reduced-cylinder operation region (step S6; Yes), the PCM 50 proceeds to step 7 and operates the engine 10 in the reduced-cylinder operation mode. Control to operate with. Specifically, the PCM 50 controls the valve stop mechanism 20 to stop the opening / closing operations of the intake valve 12 and the exhaust valve 17 of the first cylinder 2A and the fourth cylinder 2D. In addition, the PCM 50 stops the ignition of the spark plug 14 and the fuel injection of the fuel injection valve 13 for the first cylinder 2A and the fourth cylinder 2D. That is, the PCM 50 opens and closes the intake valve 12 and the exhaust valve 17 only for the second cylinder 2B and the third cylinder 2C (the valve stop mechanism for the valves 12 and 17 of the second cylinder 2B and the third cylinder 2C). And the ignition of the spark plug 14 and the fuel injection of the fuel injection valve 13 are performed.

  On the other hand, as a result of the determination in step S6, if it is determined that the current engine speed and engine torque are not included in the reduced-cylinder operation region (step S6; No), the PCM 50 proceeds to step 8 to start the engine 10 Control to operate in all-cylinder operation mode. Specifically, the PCM 50 opens and closes the intake valves 12 and the exhaust valves 17 for all the cylinders 2A to 2D (the operation of the valve stop mechanism 20 for the valves 12 and 17 of all the cylinders 2A to 2D is performed). And the ignition of the spark plug 14 and the fuel injection of the fuel injection valve 13 are performed.

<Effect>
Next, functions and effects of the engine control apparatus according to the embodiment of the present invention will be described.

  In the present embodiment, the PCM 50 changes the reduced-cylinder operation region in accordance with the intake air temperature. Specifically, the PCM 50 determines the engine torque in the reduced-cylinder operation region (the engine torque is determined when the operation mode is switched). Corresponding to the judgment value). As a result, in the reduced-cylinder operation mode, even if the intake air temperature changes, the engine torque can be appropriately increased according to the driver's accelerator depressing operation, and the uncomfortable feeling given to the driver can be suppressed. For example, when the intake air temperature is relatively high, it is possible to suppress the occurrence of the problem that the engine torque does not increase appropriately on the high load side in the reduced-cylinder operation region.

  Further, in this embodiment, the PCM 50 obtains the maximum filling amount based on the intake air temperature, and applies the maximum filling amount to the engine torque when operating at the stoichiometric air-fuel ratio as the upper limit value of the engine torque in the reduced cylinder operation region. Set as. As a result, it is possible to set a reduced-cylinder operation region that appropriately takes into account the air charge amount and engine torque that change according to the intake air temperature.

  Further, in the present embodiment, the PCM 50 changes the reduced-cylinder operation region in accordance with the atmospheric pressure in addition to the intake air temperature. Therefore, the reduced-cylinder operation region that appropriately takes into consideration the intake air temperature and the intake air density corresponding to the atmospheric pressure. Can be set.

<Modification>
Next, a modification of the above embodiment will be described.

  In the above-described embodiment, the reduced-cylinder operation region is changed according to the temperature detected by the intake air temperature sensor 33. However, instead of the temperature detected by the intake air temperature sensor 33, the engine detected by the water temperature sensor 35 is used. The reduced-cylinder operation region may be changed according to the water temperature, the outside air temperature detected by the outside air temperature sensor, or the like. This is because the engine water temperature and the outside air temperature are related to the intake air temperature of the engine 10. Further, instead of the temperature detected by the sensor as described above, the intake air temperature may be estimated based on a predetermined model or arithmetic expression, and the reduced-cylinder operation region may be changed according to the estimated intake air temperature. As described above, the intake air temperature detected by the intake air temperature sensor 33, the engine water temperature detected by the water temperature sensor 35, the outside air temperature detected by the outside air temperature sensor, and the estimated intake air temperature are “ It corresponds to “intake temperature related value”.

  In the above-described embodiment, the reduced-cylinder operation region is defined based on the engine torque. In other words, the operation mode is switched based on the engine torque. Parameters such as the fuel injection amount, the engine load, the operating state of the variable valve mechanisms 18 and 19, the accelerator opening, and the throttle opening may be applied. When such a parameter is applied instead of the engine torque, the upper limit value (determination value) that defines the reduced-cylinder operation region is naturally defined by the parameter. The various parameters described above correspond to “engine torque-related values” in the present invention. Further, at least some of these parameters correspond to the “engine speed related value” in the present invention.

DESCRIPTION OF SYMBOLS 1 Intake passage 2 (2A-2D) Cylinder 5 Throttle valve 10 Engine 13 Fuel injection valve 14 Spark plug 18 Variable intake valve mechanism 20 Valve stop mechanism 30 Accelerator opening sensor 33 Intake temperature sensor 39 Atmospheric pressure sensor 50 PCM
100 engine system

In order to achieve the above object, the present invention includes a plurality of cylinders, a reduced-cylinder operation mode in which combustion of some of the plurality of cylinders is stopped, and all-cylinder operation in which combustion is performed in all of the plurality of cylinders. When the engine that can be operated by switching the mode and the engine torque related value related to the engine torque is equal to or lower than the predetermined judgment value, the engine is operated in the reduced cylinder operation mode, and the engine torque related value is determined from the judgment value. Control means for causing the engine to operate in the all-cylinder operation mode, and further comprising an acquisition means for acquiring an intake air temperature related value related to the intake air temperature of the engine. means obtains the maximum air charge of the cylinder to be burned in the acquired intake air temperature-related values on the basis of reduced-cylinder operation mode, it sets the determination value in accordance with the maximum air charge amount, the intake air temperature function The smaller the value, the larger the maximum air charge, as the maximum air charge amount is large, to increase the determination value, it is characterized.
According to the present invention configured as described above, the determination value for determining the engine torque related value in the switching of the operation mode between the reduced cylinder operation mode and the all cylinder operation mode is changed according to the intake air temperature related value degree. make. Specifically, when the intake air temperature-related value is small, the determination value is set higher than when the intake air temperature-related value is large, so that even if the intake air temperature changes in the reduced cylinder operation mode, the driver can depress the accelerator. Accordingly, the engine torque can be appropriately increased, and the uncomfortable feeling given to the driver can be suppressed. For example, when the intake air temperature is relatively high, it is possible to suppress the occurrence of the problem that the engine torque does not increase appropriately on the high load side in the reduced-cylinder operation region. Also, the maximum air filling amount that can be filled in the cylinder of the engine is obtained based on the intake air temperature related value, and the determination value is set based on this maximum air filling amount, so the maximum air filling amount that changes according to the intake air temperature is set. It is possible to set a judgment value appropriately taken into consideration.

In another aspect, it is possible to operate by switching between a reduced-cylinder operation mode in which a plurality of cylinders are provided and combustion of some of the cylinders is stopped and an all-cylinder operation mode in which combustion is performed in all of the plurality of cylinders. An engine control device having acquisition means for acquiring an intake air temperature related value related to the intake air temperature of the engine, and the control device determines an operation region in the reduced-cylinder operation mode based on the acquired intake air temperature related value. have a reduced-cylinder operation area setting means for setting, operating region of the reduced-cylinder operation mode is defined based on the engine speed related value related to rotational speed of the engine torque-related value and the engine associated with the torque of the engine The reduced-cylinder operation region setting means obtains the maximum air filling amount of the cylinder that burns in the reduced-cylinder operation mode based on the intake air temperature related value, and the operation range of the reduced-cylinder operation mode according to the maximum air filling amount. It sets the upper limit of the engine torque-related value, the smaller the intake air temperature-related values, thereby increasing the maximum air charge, as the maximum air charge amount is large, to increase the upper limit value, characterized in that.
According to the present invention configured as described above, the reduced-cylinder operation region is set according to the intake air temperature related value . Specifically, the upper limit value of the reduced-cylinder operation range defined by the engine torque related value is set based on the intake air temperature related value, and when the intake air temperature related value is small, this is greater than when the intake air temperature related value is large. Since the upper limit is increased, even if the intake air temperature changes in the reduced-cylinder operation mode, the engine torque can be appropriately increased according to the driver's accelerator depressing operation, and the uncomfortable feeling given to the driver can be suppressed. Become. Also, the maximum air filling amount that can be filled in the cylinder of the engine is obtained based on the intake air temperature related value, and the upper limit value is set according to this maximum air filling amount, so the maximum air that changes according to the intake air temperature It is possible to set a determination value that appropriately takes into account the filling amount.

Claims (7)

An engine that includes a plurality of cylinders and that can be operated by switching between a reduced-cylinder operation mode in which combustion of some of the cylinders is stopped and an all-cylinder operation mode in which combustion is performed in all of the plurality of cylinders;
Control means for operating the engine in the reduced-cylinder operation mode when an engine torque related value related to the engine torque is equal to or less than a predetermined determination value;
An engine control device comprising:
An acquisition means for acquiring an intake air temperature related value related to the intake air temperature of the engine;
The control means sets the determination value according to the acquired intake air temperature related value;
An engine control device. The control means obtains a maximum air filling amount of a cylinder that burns in the reduced-cylinder operation mode based on the intake air temperature related value, and sets the determination value according to the maximum air filling amount.
The engine control apparatus according to claim 1. The control means obtains a generated torque value of the engine when operating at a stoichiometric air-fuel ratio at the maximum air charge amount, and sets the determination value according to the generated torque value.
The engine control device according to claim 2. It further has an atmospheric pressure acquisition means for acquiring atmospheric pressure,
The control means sets the determination value according to the atmospheric pressure in addition to the intake air temperature related value.
The engine control device according to any one of claims 1 to 3. An engine control device that has a plurality of cylinders and can be operated by switching between a reduced-cylinder operation mode in which combustion of some of the cylinders is stopped and an all-cylinder operation mode in which combustion is performed in all of the plurality of cylinders. There,
Obtaining means for obtaining an intake air temperature related value related to the intake air temperature of the engine;
The control device includes a reduced-cylinder operation region setting unit that sets an operation region in the reduced-cylinder operation mode according to the acquired intake air temperature related value.
An engine control device. The operation region of the reduced cylinder operation mode is defined based on an engine torque related value related to the engine torque and an engine speed related value related to the engine speed,
The reduced-cylinder operation region setting means sets an upper limit value of the operation region in the reduced-cylinder operation mode defined by the engine torque-related value according to the intake air temperature-related value.
The engine control device according to claim 5. An engine control device that has a plurality of cylinders and can be operated by switching between a reduced-cylinder operation mode in which combustion of some of the cylinders is stopped and an all-cylinder operation mode in which combustion is performed in all of the plurality of cylinders. There,
Obtaining means for obtaining an intake air temperature related value related to the intake air temperature of the engine;
The control device has an upper limit value setting means for setting an upper limit value of the engine torque related value that can be operated in the reduced-cylinder operation mode with respect to an engine torque related value related to the torque of the engine,
When the acquired intake air temperature related value is the first temperature, the upper limit value setting means is more preferable than when the acquired intake air temperature related value is the second temperature higher than the first temperature. Set a high upper limit,
An engine control device.

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