JP6330751B2 - Engine control device - Google Patents

Description

  The technology disclosed herein relates to an engine control device including a turbocharger.

  2. Description of the Related Art Conventionally, an engine that has a canister that collects evaporated fuel generated in a fuel tank and a purge passage that connects the intake passage and the canister and supplies evaporated fuel generated in the fuel tank as a purge gas to an intake system is known. It has been. In this type of engine, a configuration in which a purge passage is branched in the middle is known.

  For example, in Patent Document 1, the purge passage is branched into a first branch passage connected to the compressor upstream side of the intake passage and a second branch passage connected to the compressor downstream side (for example, a surge tank). A configuration is disclosed. The downstream end of the first branch passage is connected to the upstream portion of the compressor via an ejector. The ejector is configured to recirculate the intake air from the downstream portion to the upstream portion of the compressor and promote the supply of purge gas by the recirculated intake air. When the intake air is supercharged, the purge gas cannot be supplied to the intake passage via the second branch passage. Therefore, the purge gas is sucked through the first branch passage by the negative pressure generated by the ejector effect. Supply to the aisle. On the other hand, when the intake air is not supercharged, the purge gas is supplied through the second branch passage.

JP 2013-174142 A

  Incidentally, there is a demand for increasing the flow rate of the purge gas passing through the purge passage (hereinafter sometimes referred to as “purge flow rate”) according to the engine operating conditions. For example, when the vehicle is traveling on high altitudes or when the fuel tank is hot, the fuel tends to volatilize, so the evaporated fuel trapped in the canister may become saturated and overflow. It is required to secure a sufficient flow rate.

  Therefore, paying attention to the fact that the supply of purge gas at the time of supercharging uses the negative pressure generated by the ejector effect, and that the magnitude of the negative pressure increases as the supercharging pressure increases, It is conceivable to increase the supercharging pressure in order to increase the flow rate. However, if the boost pressure is increased in order to increase the purge flow rate, the engine output torque will increase.

  The technology disclosed herein has been made in view of the above points, and the purpose thereof is to increase the purge flow rate by increasing the supercharging pressure and to suppress the increase in output torque associated therewith. It is in.

The technology disclosed herein includes a turbocharger having a compressor provided in an intake passage of an engine, a canister for recovering evaporated fuel in a fuel tank, an intake passage on the downstream side of the compressor, and an upstream side of the compressor of provided so as to connect the intake passage, and an ejector for generating a negative pressure by the intake refluxing into the compressor upstream of the intake passage from the intake passage of the compressor downstream, evaporated fuel that has been collected by the canister And a purge system for introducing the ejector into the intake passage upstream of the compressor , wherein the external air pressure is lower than a predetermined reference pressure or the intake air temperature is a predetermined air pressure. when reference is greater than the temperature, and the determined increase requesting unit requires an increase in the flow rate of purge gas Wherein at the time of determination by the increase requesting unit comprises a bulking execution unit for executing the purge increase control for increasing the flow rate of the purge gas as compared with the time of non-determination, an output adjusting unit for adjusting the output torque of the engine, the said The increase execution unit increases the flow rate of the purge gas by the ejector by increasing the supercharging pressure of the turbocharger before the purge increase control is executed in the purge increase control, and the output In the purge increase control, the adjustment unit changes the valve opening degree of the throttle valve provided in the intake passage to the valve closing side in accordance with the increase in the supercharging pressure by the increase execution unit.

  Generally, when the supercharging pressure is increased, the differential pressure between the downstream side and the upstream side of the compressor is increased, and the recirculation of the intake air via the ejector is promoted. When the recirculation of the intake air is promoted, the supply of the purge gas through the purge passage is promoted accordingly, and the purge flow rate is increased. On the other hand, as the supercharging pressure increases, the intake air amount introduced into the cylinder (hereinafter sometimes referred to as “filling amount”) may increase, and as a result, the output torque may increase.

According to this configuration, the control device increases the purge flow rate by increasing the supercharging pressure, and suppresses an increase in output torque accompanying an increase in the supercharging pressure. Thereby, the purge flow rate can be increased while suppressing an excessive increase in output torque .

Further, according to the above configuration, the output adjustment unit reduces the filling amount by reducing the valve opening of the throttle valve in the purge increase control. That is, an increase in output torque accompanying an increase in supercharging pressure can be suppressed by adjusting the filling amount.

The filling amount is adjusted via the throttle valve instead of adjusting the filling amount by adjusting the opening / closing timing of the intake valve or adjusting the output torque by so-called ignition retard that retards the ignition timing from normal. By doing so, the following advantages can be obtained. In other words, the adjustment of the opening / closing timing of the intake valve and the control of the ignition timing are used for various controls related to engine operation. Therefore, the adjustment of the opening / closing timing of the intake valve and the ignition are controlled by suppressing the output torque through the throttle valve. Timing control can be used for another control. This is advantageous in improving the controllability of the engine. Note that this description does not intend to exclude a configuration that suppresses an increase in output torque by adjusting the opening / closing timing of the intake valve, performing ignition retard, or the like. In addition, closing the throttle valve makes it easier to increase the boost pressure compared to the case where the output torque is suppressed by adjusting the opening / closing timing of the intake valve, so the purge flow rate can be increased quickly. . In addition, fuel efficiency is improved as compared with the case where the output torque is adjusted by ignition retard .

One general, depending on the external atmospheric pressure, the volatile ease of fuel changes. For example, in an environment where the external air pressure is low, such as in a highland, fuel is more volatile than in a lowland.

According to the arrangement, the increase requesting unit by determining based on the necessity of increasing the purge flow rate to the outside pressure can be determined precisely when to increase the purge flow rate. As a result, the purge increase control can be performed at a more appropriate timing, which is advantageous in reducing the chance that the output torque can increase due to the increase in the supercharging pressure.

  Further, the increase request unit determines that the purge gas flow rate needs to be increased when a temperature in the fuel tank or a temperature related to the temperature in the fuel tank is higher than a predetermined reference temperature. May be.

  Here, the “temperature related to the temperature in the fuel tank” means a temperature at which the temperature in the fuel tank can be indirectly detected. For example, an outside air temperature or an upstream portion of the compressor in the intake passage Including the temperature of the flowing intake air.

  In general, the ease of volatilization of the fuel varies depending on the temperature in the fuel tank. For example, when the inside of the fuel tank is hot, the fuel is more volatile than when the temperature is low.

  According to this configuration, the increase request unit increases the purge flow rate by determining whether the purge flow rate needs to be increased based on the temperature in the fuel tank or a temperature related to the temperature in the fuel tank. It is possible to accurately determine when to do. As a result, the purge increase control can be performed at a more appropriate timing, which is advantageous in reducing the chance that the output torque can increase due to the increase in the supercharging pressure.

  A bypass passage for bypassing the turbine of the turbocharger; a waste gate valve for controlling a flow rate of exhaust gas flowing through the bypass passage; and a target output torque of the engine acquired based on an operating state of the engine. A target supercharging pressure setting unit that sets the target supercharging pressure of the turbocharger and a target wastegate valve opening required to realize the target supercharging pressure are set. And a wastegate valve control unit that controls the valve opening of the wastegate valve so as to achieve the target wastegate valve opening, and the increase execution unit is configured to perform the purge increase control in the purge increase control. By setting a boost pressure equal to or higher than the target boost pressure set by the target boost pressure setting unit as a target value, the boost pressure is reduced. It may be allowed to rise.

  The canister may be connected to an air release pipe that opens the canister to the atmosphere.

  According to the engine control apparatus, the purge flow rate can be increased while suppressing an excessive increase in output torque.

FIG. 1 is a schematic configuration diagram of an engine. FIG. 2 is a functional configuration diagram of the ECU. FIG. 3 is a flowchart of processing relating to torque-based control. FIG. 4 is a flowchart of processing related to purge increase control.

  Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

<Engine configuration>
FIG. 1 is a schematic configuration diagram of an engine to which an engine control apparatus according to an embodiment is applied.

  As shown in FIG. 1, an engine 100 (for example, a gasoline engine) mainly includes an intake passage 10 through which intake air (air) introduced from the outside passes, and a plurality of cylinders (only one) connected to the intake passage 10. The engine main body 20 that generates the power of the vehicle by burning the air-fuel mixture of the intake air supplied from the intake passage 10 and the fuel supplied from the fuel injection valve 23, which will be described later, and the engine main body An exhaust passage 30 for exhausting exhaust gas generated by combustion in the engine 20, a turbocharger 40 for supercharging intake air using the energy of the exhaust, a fuel tank 50, and evaporated fuel generated in the fuel tank 50 A purge system 60 that supplies the intake passage 10 and an ECU (Electronic Control Unit) 70 that controls the entire engine 100 are included.

  In the intake passage 10, in order from the upstream side, an air cleaner 11 that purifies intake air introduced from the outside, a compressor 41 of a turbocharger 40 that boosts the intake air that passes through, and an intercooler 12 that cools the intake air that passes through. A throttle valve 13 for adjusting the amount of intake air passing therethrough, and an intake manifold 14 having a surge tank 14a for temporarily storing intake air supplied to the engine body 20.

  The engine body 20 mainly includes an intake valve 22 that opens and closes an intake port, a fuel injection valve 23 that injects fuel into the cylinder 21, and an ignition that ignites a mixture of intake air and fuel supplied into the cylinder 21. It has a plug 24, a piston 27 that reciprocates by combustion of the air-fuel mixture in the cylinder 21, a crankshaft 28 that is rotated by reciprocation of the piston 27, and an exhaust valve 29 that opens and closes an exhaust port.

  The exhaust passage 30 is rotated by exhaust gas passing through in order from the upstream side, and the turbocharger turbine 42 that rotates the compressor 41 by this rotation, such as a NOx catalyst, a three-way catalyst, an oxidation catalyst, and the like. An exhaust purification catalyst 31 having an exhaust purification function is provided.

  The exhaust passage 30 is provided with a bypass passage 32 that bypasses the turbine 42 of the turbocharger 40 for exhaust. The bypass passage 32 is provided with a waste gate valve (WG valve) 33 that controls the flow rate of the exhaust gas flowing through the bypass passage 32.

  The purge system 60 adsorbs and stores the evaporated fuel generated in the fuel tank 50, connects the canister 61 and the intake passage 10, and purge passage that leads the purge gas containing the evaporated fuel from the canister 61 to the intake passage 10. 62 and a purge valve 66 provided in the purge passage 62.

  The canister 61 contains activated carbon that removably adsorbs fuel vapor. Connected to the canister 61 are a fuel vapor pipe 61 a for introducing fuel vapor in the fuel tank 50, an air release pipe 61 b for opening the canister 61 to the atmosphere, and a purge passage 62. Although not shown, the atmosphere release pipe 61b is provided with an air filter that filters air flowing into the canister 61 and a valve that opens and closes the atmosphere release pipe 61b. The valve is opened when the evaporated fuel is purged.

  The upstream portion of the purge passage 62 is formed by a single passage and is connected to the canister 61. On the other hand, the downstream portion of the purge passage 62 is branched into two passages and connected to two locations of the intake passage 10.

  Specifically, the purge passage 62 includes a common passage 63 on the upstream side, and a first branch passage 64 and a second branch passage 65 on the downstream side. The upstream end of the common passage 63 is connected to the canister 61. The upstream end of the first branch passage 64 and the upstream end of the second branch passage 65 are connected to the downstream end of the common passage 63. The downstream end of the first branch passage 64 is connected to a portion of the intake passage 10 on the upstream side of the compressor 41 via an ejector 67 described later. The downstream end of the second branch passage 65 is connected to the surge tank 14 a of the intake passage 10.

  A purge valve 66 is provided in the common passage 63. The purge valve 66 is an electronically controlled valve that is opened and closed by a control signal from the ECU 70. The first branch passage 64 is provided with a check valve 64 a that prevents a reverse flow of intake air from the intake passage 10. The second branch passage 65 is provided with a check valve 65a that prevents the backflow of the intake air from the intake passage 10.

  The ejector 67 connects the main body 67a, the introduction nozzle 67b for connecting the downstream portion of the compressor 41 in the intake passage 10 and the main body 67a, and the upstream portion of the compressor 41 in the intake passage 10 and the main body 67a. And a discharge path 67c. The first branch passage 64 is connected to the main body 67 a and constitutes a part of the ejector 67. The tip of the introduction nozzle 67b is tapered, and the intake air recirculated through the introduction nozzle 67b is depressurized at the tip, and negative pressure is generated around the tip of the introduction nozzle 67b. Due to this negative pressure, the purge gas is sucked into the main body 67a from the first branch passage 64. The sucked purge gas is introduced to the upstream side of the compressor 41 in the intake passage 10 through the discharge passage 67c together with the intake air recirculated from the introduction nozzle 67b.

  When the turbocharger 40 is not supercharging intake air (hereinafter referred to as “non-supercharging”), the purge gas is introduced into the intake passage 10 via the second branch passage 65. Specifically, at the time of non-supercharging, since the pressure on the upstream side of the compressor 41 in the intake passage 10 is higher than the pressure on the downstream side of the compressor 41, the recirculation of the intake air through the ejector 67 does not occur. Therefore, the pressure at the downstream end of the first branch passage 64 becomes the pressure of the portion of the intake passage 10 to which the ejector 67 is connected, and the pressure is substantially equal to the atmospheric pressure (outside air pressure). Since the canister 61 is open to atmospheric pressure, the differential pressure between the upstream end and the downstream end of the first branch passage 64 is substantially zero, and the purge gas does not flow through the first branch passage 64.

  On the other hand, the surge tank 14a to which the downstream end of the second branch passage 65 is connected has a negative pressure. Therefore, the purge gas flowing through the purge passage 62 is introduced into the surge tank 14 a via the second branch passage 65.

  When the turbocharger 40 is supercharging the intake air (hereinafter referred to as “supercharging”), the purge gas is introduced into the intake passage 10 via the first branch passage 64. Specifically, at the time of supercharging, the surge tank 14a has a positive pressure due to supercharging. As described above, since the canister 61 is open to the atmospheric pressure, the pressure at the downstream end of the second branch passage 65 is higher than the pressure at the upstream end of the second branch passage 65. Therefore, the purge gas does not flow through the second branch passage 65. Note that since the check valve 65 a is provided in the second branch passage 65, the intake air in the intake passage 10 does not flow back through the second branch passage 65.

  On the other hand, due to the supercharging by the compressor 41, the pressure on the downstream side of the compressor 41 in the intake passage 10 is higher than the pressure on the upstream side of the compressor 41, so that the intake air recirculates via the ejector 67. As a result, the purge gas is sucked from the first branch passage 64, and the sucked purge gas is introduced to the upstream side of the compressor 41 in the intake passage 10. Thus, the purge gas flowing through the purge passage 62 is introduced into the intake passage 10 via the first branch passage 64.

  In addition, during a transition such as immediately after the start of supercharging or immediately after stopping supercharging, the purge gas is sucked from the first branch passage 64 by the ejector 67, and the surge tank from the second branch passage 65 is caused by the negative pressure of the surge tank 14a. A purge gas may be introduced into 14a. That is, the purge gas can be supplied to the intake passage 10 through both the first branch passage 64 and the second branch passage 65.

  The purge flow rate, which is the flow rate of the purge gas flowing through the purge passage 62, is adjusted by the purge valve 66 regardless of whether it is supercharged, non-supercharged, or transient.

  Further, the engine 100 shown in FIG. 1 is provided with various sensors. Specifically, an airflow sensor 81 for detecting the intake air flow rate and a temperature sensor 85 for detecting the intake air temperature are provided in a portion of the intake passage 10 between the air cleaner 11 and the compressor 41. A first pressure sensor 82 that detects the supercharging pressure is provided in a portion of the intake passage 10 between the compressor 41 and the throttle valve 13. Further, a second pressure sensor 83 for detecting the intake manifold pressure is provided in a portion of the intake passage 10 on the downstream side of the throttle valve 13 (specifically, in the surge tank 14a). The engine body 20 is provided with a crank angle sensor 86 that detects the crank angle of the crankshaft 28. In the exhaust passage 30, a WG opening degree sensor 87 that detects the WG opening degree that is the opening degree of the WG valve 33 is provided, and an oxygen concentration in the exhaust gas is detected in a portion between the turbine 42 and the exhaust purification catalyst 31. An O2 sensor 84 is provided.

  The airflow sensor 81 outputs the detected intake air flow rate to the ECU 70. The temperature sensor 85 outputs the detected intake air temperature to the ECU 70. The first pressure sensor 82 outputs a detection signal corresponding to the detected supercharging pressure to the ECU 70. The second pressure sensor 83 outputs a detection signal corresponding to the detected intake manifold pressure to the ECU 70. The crank angle sensor 86 outputs a detection signal corresponding to the detected crank angle to the ECU 70. The WG opening sensor 87 supplies a detection signal corresponding to the detected WG opening to the ECU 70, and the O2 sensor 84 outputs a detection signal corresponding to the detected oxygen concentration to the ECU 70. Further, the engine 100 is provided with an atmospheric pressure sensor 80 for detecting atmospheric pressure, and the atmospheric pressure sensor 80 outputs a detection signal corresponding to the detected atmospheric pressure to the ECU 70.

  The ECU 70 includes a CPU, a ROM for storing various programs (including a basic control program such as an OS and an application program that is activated on the OS to realize a specific function), and various data. It is comprised by the computer provided with internal memory like RAM. The ECU 70 performs various controls and processes based on the detection signals supplied from the various sensors described above. The ECU 70 is an example of an “engine control device”.

  FIG. 2 shows a functional configuration diagram of the ECU 70.

  The ECU 70 executes a purge increase control for increasing the purge flow rate passing through the purge passage 62 by increasing the supercharging pressure of the turbocharger 40. In this purge increase control, the output accompanying the increase of the supercharging pressure is executed. Output adjustment control that suppresses the increase in torque is executed.

  Specifically, ECU 70 sets a control value (hereinafter referred to as “basic value”) that is a basis for various actuators in order to control output torque of engine 100, and an operating condition of engine 100. Purging for executing the purge increase control and the output adjustment control based on the operating condition acquisition unit 72 to be acquired, the basic value set by the base setting unit 71, and the operating condition acquired by the operating condition acquisition unit 72 And a control unit 73.

<Base setting section>
The base setting unit 71 uses the target values of the output torque of the engine 100 (hereinafter referred to as “target torque”) acquired based on the operating state of the engine 100 as a reference, A so-called torque base control is executed to control the ignition timing by the spark plug 24, the opening / closing timing of the intake valve 22, the fuel injection amount from the fuel injection valve 23, and the like. In the torque-based control, a target torque (target output torque) is acquired based on the operating state of the engine 100, and the control value of each actuator is set to a basic value that allows the target torque to be obtained. The base setting unit 71 is an example of a “target boost pressure setting unit” and an example of a “waste gate valve control unit”. Instead of this example, the base setting unit 71 may be composed of a plurality of blocks.

  In the torque base control by the base setting unit 71, the control of the throttle valve 13 and the WG valve 33 will be mainly described with reference to FIG. FIG. 3 is a flowchart of processing relating to torque-based control.

  In the torque base control, first, in step S1, the base setting unit 71 detects the operating state of the engine 100. Specifically, the engine speed of the engine 100 calculated based on the crank angle sensor 86 (hereinafter referred to as “engine speed”), vehicle speed, accelerator opening, gear ratio, and the like are determined. Read as.

  In step S2, the base setting unit 71 acquires a target acceleration corresponding to the detected driving state.

  In step S3, the base setting unit 71 acquires a target torque necessary to realize the acquired target acceleration.

  In step S <b> 4, the base setting unit 71 sets a target value (hereinafter referred to as “target charging efficiency”) of the charging efficiency necessary for realizing the acquired target torque. Specifically, the target charging efficiency is obtained based on the target torque, the engine speed, and the target value of the indicated mean effective pressure (hereinafter referred to as “target indicated mean effective pressure”). The target indicated mean effective pressure is obtained based on the target torque, the mechanical resistance that becomes torque loss, and the pump loss (pumping loss).

  In step S5, a target value of the amount of intake air in the intake manifold 14 necessary for realizing the set target charging efficiency (hereinafter referred to as “target intake manifold air amount”) is acquired. The target intake manifold air amount is obtained based on the intake manifold temperature detected by the second pressure sensor 83, a target value of the intake manifold pressure (hereinafter referred to as “target intake manifold pressure”), and the opening / closing timing of the intake valve 22. The target intake manifold pressure is obtained based on an intake characteristic map that is preliminarily stored in the internal memory of the ECU 70 and is defined in association with the target intake manifold air amount and intake manifold temperature and the corresponding target intake manifold pressure.

  After step S5, steps S6 to S8 and steps S9 to S11 are performed in parallel.

  In step S <b> 6, the base setting unit 71 obtains a target value of the flow rate of the intake air that passes through the throttle valve 13 (hereinafter referred to as “target throttle passage flow rate”) that is necessary to realize the target intake manifold air amount. . The target throttle passage flow rate is the target charging efficiency acquired in step S4, the target intake air amount acquired in step S5, and the estimated value of the current intake manifold air amount (hereinafter referred to as “actual intake manifold air amount”). Based on and. The actual intake manifold air amount is estimated based on the intake manifold pressure and the intake manifold temperature detected by the second pressure sensor 83. The actual intake manifold air amount may be estimated by calculating a balance between the amount of air flowing into the intake manifold 14 and the amount of air flowing out of the intake manifold 14 into the cylinder 21.

  In step S <b> 7, the base setting unit 71 sets a target value of the valve opening of the throttle valve 13 (hereinafter referred to as “target throttle opening”) that is necessary to realize the acquired target throttle passage flow rate. To do. The target throttle opening includes the target throttle passage flow rate, the intake pressure (supercharging pressure) upstream of the throttle valve 13 detected by the first pressure sensor 82, and the throttle valve detected by the second pressure sensor 83. 13 is set based on the intake pressure on the downstream side.

  In step S8, the base setting unit 71 outputs a control signal for driving the throttle valve 13 so that the valve opening of the throttle valve 13 becomes the target throttle opening, and realizes the target torque. Control signals corresponding to the respective control values (basic values) are output to the spark plug 24, the intake valve 22 and the fuel injection valve 23.

  On the other hand, in step S <b> 9, the base setting unit 71 sets a target supercharging pressure that is a target value of the supercharging pressure that is necessary to realize the target intake manifold air amount. The target boost pressure is obtained based on a boost pressure map that is stored in advance in the internal memory of the ECU 70 and that is defined in association with the engine speed and the target charging efficiency and the opening / closing timing of the intake valve 22 corresponding thereto. .

  In step S10, the base setting unit 71 acquires a target turbine flow rate that is a target value of the flow rate that passes through the turbine 4b, based on the set target supercharging pressure. Specifically, the target turbine flow rate is obtained based on the target compressor driving force that is the target value of the compressor driving force, the engine speed, and the like. The target compressor driving force is obtained based on the target supercharging pressure.

  In step S <b> 11, the base setting unit 71 sets a target value of the valve opening of the WG valve 33 (hereinafter referred to as “target WG opening”) necessary for realizing the calculated target turbine flow rate. The target WG opening (target waste gate valve opening) is obtained based on the target turbine flow rate and the total exhaust flow rate.

  In step S12, the base setting unit 51 outputs a control signal for adjusting the valve opening of the WG valve 33 so as to realize the target WG opening.

  Note that the order of these steps is an example, and the order of the steps may be appropriately changed within a possible range, or a plurality of steps may be processed in parallel. For example, the steps that follow from step S6 to step S8 and the steps that follow from step S9 to step S12 may be processed one by one without being processed in parallel.

<Operating condition acquisition unit>
The operating condition acquisition unit 72 acquires the operating conditions of the engine 100. Here, the “operating condition” is a condition that can affect the evaporation of fuel in the fuel tank 50, such as atmospheric pressure or temperature in the fuel tank 50. Specifically, the operating condition acquisition unit 72 acquires the current atmospheric pressure detected by the atmospheric pressure sensor 80 and the current intake air temperature detected by the temperature sensor 85 as the operating conditions of the engine 100, and acquires them. A signal corresponding to the result is output to the purge control unit 73. The current intake air temperature is an example of “a temperature related to the temperature in the fuel tank”.

<Purge control unit>
The purge control unit 73 needs to increase the purge flow rate during supercharging (when the engine 100 is in the supercharging region) and the supercharging region determining unit 77 that determines whether or not the engine 100 is in the supercharging region. An increase request unit 74 that determines whether or not the purge flow rate needs to be increased by the increase request unit 74, and an increase execution unit 75 that executes purge increase control when the increase request unit 74 determines that the purge flow rate needs to be increased. And an output adjustment unit 76 that adjusts the output torque of the engine 100. In the purge increase control, the increase execution unit 75 increases the purge flow rate by increasing the supercharging pressure of the turbocharger 40 before the purge increase control is executed. Here, the increase of the supercharging pressure is executed through the control of the WG valve 33. In the purge increase control, the output adjustment unit 76 executes output adjustment control that suppresses the output torque of the engine 100 that accompanies the increase in supercharging pressure by the increase execution unit 75. Here, the output adjustment control is executed through the control of the throttle valve 13.

-Supercharging area judgment part-
First, the supercharging region determination unit 77 determines whether or not the engine 100 is in the supercharging region based on the target supercharging pressure set by the base setting unit 71.

  Specifically, the supercharging region determination unit 77 outputs a supercharging signal indicating that the engine 100 is in the supercharging region to the increase request unit 74 when the target supercharging pressure is larger than the atmospheric pressure. On the other hand, when the target supercharging pressure is smaller than the atmospheric pressure, such a control signal is not output assuming that the engine 100 is not in the supercharging region. During such non-supercharging (when the engine 100 is not in the supercharging region), the purge gas is introduced into the intake passage 10 via the second branch passage 65 as described above.

-Increase request section-
When the increase request unit 74 receives the supercharging signal from the supercharging region determination unit 77, the increase request unit 74 determines whether or not the purge flow rate needs to be increased based on the operation condition acquired by the operation condition acquisition unit 72.

  Specifically, the increase request unit 74 determines whether or not the engine 100 is in a state where the fuel is liable to volatilize, for example, when the vehicle is traveling on high ground or when the fuel tank 50 is hot. If it is determined that it is in a state where it is likely to volatilize, an increase in the purge gas is requested. Specifically, the increase request unit 74 determines whether the current atmospheric pressure detected by the atmospheric pressure sensor 80 is lower than a predetermined reference pressure, or the current intake air temperature detected by the temperature sensor 85 is a predetermined reference. When the temperature is higher than the temperature, it is determined that the fuel is likely to volatilize and it is determined that the purge flow rate needs to be increased. Then, the increase request unit 74 outputs an increase signal to the increase execution unit 75 and the output adjustment unit 76 in order to increase the purge flow rate. Here, when the current atmospheric pressure is higher than the reference pressure and the current intake air temperature is lower than the reference temperature, it is determined that an increase in the purge flow rate is unnecessary. In this case, supercharging is performed to achieve the target supercharging pressure set by the base setting unit 71, and the purge flow rate is introduced into the intake passage 10 via the first branch passage 64 without being increased. The

-Increase execution unit-
When the increase execution unit 75 receives the increase signal from the increase request unit 74, the increase execution unit 75 executes purge increase control for increasing the purge flow rate.

  Specifically, in the purge increase control, the increase execution unit 75 changes (increases) the target boost pressure by setting a boost pressure equal to or higher than the basic value set by the base setting unit 71 as the target boost pressure. ).

  The increase execution unit 75 changes the target turbine flow rate and thus the target WG opening based on the changed target boost pressure. In this case, the target turbine flow rate increases from the flow rate corresponding to the basic value according to the increase in the target supercharging pressure. On the other hand, the target WG opening decreases from the basic value according to the increase in the target turbine flow rate. The increase execution unit 75 outputs a control signal corresponding to the changed target WG opening to the WG valve 33. Thereby, the valve opening degree of the WG valve 33 is changed to the valve closing side, and the supercharging pressure of the turbocharger 40 is increased as compared with before the purge increase control is executed.

  When the supercharging pressure rises, the differential pressure between the downstream side and the upstream side of the compressor 41 in the intake passage 10 increases, and the recirculation of the intake air via the ejector 67 is promoted. When the recirculation of the intake air is promoted, the introduction of the purge gas via the first branch passage 64 is promoted accordingly, and the purge flow rate is increased compared to before the purge increase control is executed. Subsequently, the increase execution unit 75 outputs a control signal to the output adjustment unit 76 in order to execute the output adjustment control.

-Output adjustment section-
In the purge increase control, upon receiving the increase signal from the increase request unit 74, the output adjustment unit 76 executes the output adjustment control that suppresses the increase in output torque.

  In the output adjustment control, the output adjustment unit 76 sets the target throttle opening based on the target charging efficiency set to the basic value by the base setting unit 71 and the target WG opening changed by the increase execution unit 75. change. Specifically, the output adjusting unit 76 decreases the target throttle opening in accordance with the increase in the target supercharging pressure in order to suppress the filling amount accompanying the increase in the supercharging pressure, and consequently the increase in the output torque. The output adjustment unit 76 outputs a control signal corresponding to the changed target throttle opening to the throttle valve 13. Thereby, the valve opening degree of the throttle valve 13 is changed to the valve closing side, and the flow rate of the intake air passing through the throttle valve 13 is reduced. By reducing the flow rate of the intake air, an increase in output torque accompanying an increase in supercharging pressure is suppressed.

  The processing related to the purge increase control described above is shown in a flowchart in FIG. This process is repeatedly executed by the ECU 70 at a predetermined cycle.

  First, in step S21, the base setting unit 71 reads the operating state of the engine 100. This step corresponds to step S1 in FIG.

  In step S22, the base setting unit 71 sets the control value of each actuator to a basic value by executing torque base control. Specifically, the base setting unit 71 acquires a target torque corresponding to the detected operating state, and sets the target charging efficiency, the target boost pressure, the target throttle opening, and the target WG opening of the throttle valve 13 as basic values. Set to. This step corresponds to step S2 to step S12 in FIG.

  In step S23, the supercharging region determination unit 77 determines whether or not the engine 100 is in the supercharging region. If it is determined that the engine 100 is in the supercharging region, the process proceeds to step S24, whereas if it is determined that the engine 100 is not in the supercharging region, the process proceeds to step S28. In step S28, the purge gas is introduced into the intake passage 10 through the second branch passage 65 as described above.

  In step S24, the increase request unit 74 determines whether or not the purge flow rate needs to be increased. Specifically, when it is determined that the purge flow rate needs to be increased, the process proceeds to step S25, and purge increase control is executed. On the other hand, if it is not determined that the purge flow rate needs to be increased, the process proceeds to step S27 without executing the purge increase control. When the process proceeds to step S27 without executing the purge increase control, the purge flow rate is introduced into the intake passage 10 via the first branch passage 64 without being increased.

  In step S5, the increase execution unit 75 changes the valve opening of the WG valve 33 to the valve closing side so that the supercharging pressure of the turbocharger 40 increases. Specifically, the increase execution unit 75 increases the target supercharging pressure from the basic value set by the base setting unit 71, and decreases the target WG opening according to the increase.

  In step S26, the output adjustment unit 76 changes the valve opening degree of the throttle valve 13 to the valve closing side so that the flow rate of the intake air passing through the throttle valve 13 decreases. Specifically, the output adjustment unit 76 decreases the target throttle opening based on the target charging efficiency set to the basic value by the base setting unit 71 and the target boost pressure changed by the increase execution unit 75. Let

  In step S27, purge gas is introduced through the first branch passage 64. When the purge increase control is being executed, increasing the supercharging pressure via the WG valve 33 facilitates the recirculation of the intake air via the ejector 67 and increases the purge flow rate via the first branch passage 64. To do. On the other hand, by decreasing the flow rate of the intake air passing through the throttle valve 13, an increase in output torque accompanying an increase in supercharging pressure is suppressed.

  Note that the order of these steps is an example, and the order of the steps may be appropriately changed within a possible range, or a plurality of steps may be processed in parallel. For example, the order of step S23 and step S24 may be switched, or step S23 and step S24 may be processed in parallel.

  As described above, the purge control unit 73 increases the purge flow rate by increasing the supercharging pressure via the WG valve 33 in the purge increase control, and increases the output torque as the supercharging pressure increases. In order to suppress it, output adjustment control is executed via the throttle valve 13. By configuring in this way, the ECU 70 can increase the purge flow rate while reducing the influence on the operating state of the engine 100.

  Specifically, for example, when the vehicle is traveling on a high altitude, or when the inside of the fuel tank 50 is at a high temperature, the fuel is likely to volatilize, so it is required to increase the purge flow rate. However, at the time of supercharging, purge gas is supplied by the ejector effect, so the purge flow rate depends on the supercharging pressure. Therefore, changing the supercharging pressure in an attempt to adjust the purge flow rate can affect the operating state of the engine 100.

  According to the above-described configuration, the ECU 70 can increase the purge flow rate by increasing the supercharging pressure while suppressing an excessive increase in output torque. Therefore, the influence of the increase in supercharging pressure on the operating state of engine 100 can be reduced by the amount that suppresses the increase in output torque. As a result, the ECU 70 can increase the purge flow rate while reducing the influence on the operating state of the engine 100.

  Further, in the output adjustment control, the purge control unit 73 can reduce the flow rate of intake air passing through the throttle valve 13 and thus the filling amount by reducing the valve opening of the throttle valve 13. As a result, in the purge increase control, the filling amount can be decreased while increasing the supercharging pressure. That is, an increase in output torque accompanying an increase in supercharging pressure can be suppressed by adjusting the filling amount.

  In addition, the charging amount is not adjusted by adjusting the opening / closing timing of the intake valve 22 or the output torque is adjusted by ignition retard, but by adjusting the filling amount via the throttle valve 13, The control of the opening / closing timing and the ignition timing can be used for another control related to the operation of the engine 100. This is advantageous in improving the controllability of the engine 100. In addition, closing the throttle valve 13 makes it possible to increase the purge flow rate more quickly because the boost pressure is more likely to rise than when the output torque is suppressed by adjusting the opening / closing timing of the intake valve 22. It becomes. In addition, fuel efficiency is improved as compared with the case where the output torque is adjusted by ignition retard.

  Further, the purge control unit 73 can accurately determine when the purge flow rate should be increased by determining whether the purge flow rate needs to be increased based on the atmospheric pressure or the intake air temperature. As a result, the purge increase control can be performed at a more appropriate timing, which is advantageous in reducing the chance that the output torque can increase as the supercharging pressure increases.

<Other embodiments>
In the above-described embodiment, the configuration including the turbocharger 40 that drives the turbine 42 by exhaust gas is illustrated. However, instead of this configuration, a turbocharger having an electric assist mechanism may be provided.

  In the above embodiment, the supercharging pressure of the turbocharger 40 is adjusted through the control of the WG valve 33 provided in the exhaust passage 30, but instead, a variable nozzle turbocharger is configured. You may adjust a supercharging pressure through control of the nozzle vane of the turbocharger 40 comprised as follows.

  In the above-described embodiment, in the output adjustment control, the purge control unit 73 is configured to suppress the increase in output torque by adjusting the filling amount through the control of the throttle valve 13. Thus, the increase in output torque may be suppressed by ignition retard. Further, the filling amount may be adjusted via a so-called intake VVT (Variable Valve Timing) that changes the opening / closing timing of the intake valve 22.

  In the above embodiment, the purge control unit 73 is configured to execute the purge increase control based on the intake air temperature detected by the temperature sensor 85, assuming that the intake air temperature and the temperature in the fuel tank 50 are related. However, instead of this configuration, a temperature sensor may be newly provided in the fuel tank 50, and the purge increase control may be executed based on the tank temperature detected by the temperature sensor. Further, an outside air temperature sensor may be newly installed at a place other than the intake passage 10, and the purge increase control may be executed based on the outside air temperature detected by the outside air temperature sensor.

  In the above-described embodiment, the purge increase control is performed based on the atmospheric pressure or the temperature related to the temperature in the fuel tank 50. However, instead of this configuration or in addition to this configuration, the engine 100 is configured. However, at the time of restart after warm-up, in other words, at the time of restart after warm-up, it may be determined that the amount of evaporated fuel generated in the fuel tank 50 has increased, and purge increase control may be executed. In this way, the overflow of the canister 61 can be suppressed more reliably.

DESCRIPTION OF SYMBOLS 100 Engine 10 Intake passage 13 Throttle valve 20 Engine main body 21 Cylinder 32 Bypass passage 33 Waste gate valve 40 Turbo supercharger 41 Compressor 42 Turbine 50 Fuel tank 61 Canister 62 Purge passage 67 Ejector 70 ECU (control device)
71 Base setting unit (target boost pressure setting unit, waste gate valve control unit)
73 Purge control unit 74 Increase request unit 75 Increase execution unit 76 Output adjustment unit

Claims (4)

A turbocharger having a compressor provided in an intake passage of the engine, a canister for recovering evaporated fuel in a fuel tank, an intake passage on the downstream side of the compressor, and an intake passage on the upstream side of the compressor are connected provided, an ejector for generating a negative pressure by the intake refluxing into the compressor upstream of the intake passage from the intake passage of the compressor downstream, evaporated fuel that has been collected by the canister of the compressor upstream by said ejector A control system for an engine comprising a purge system for introducing into the intake passage,
An increase request unit that determines that the flow rate of the purge gas needs to be increased when the external air pressure is lower than a predetermined reference pressure or when the intake air temperature is higher than a predetermined reference temperature ;
Wherein at the time of determination by the increase requesting unit, and a bulking execution unit for executing the purge increase control for increasing the flow rate of the purge gas as compared to during non-determination,
An output adjustment unit for adjusting the output torque of the engine,
The increase execution unit increases the flow rate of the purge gas by the ejector by increasing the boost pressure of the turbocharger in the purge increase control from before the purge increase control is executed,
In the purge increase control, the output adjustment unit changes a valve opening degree of a throttle valve provided in the intake passage to a valve closing side according to an increase in supercharging pressure by the increase execution unit. Engine control device. The engine control device according to claim 1 ,
The increase request unit determines that the flow rate of the purge gas needs to be increased when a temperature in the fuel tank or a temperature related to the temperature in the fuel tank is higher than a predetermined reference temperature. An engine control device. The engine control device according to claim 1 or 2 ,
A bypass passage for bypassing the turbine of the turbocharger;
A waste gate valve for controlling the flow rate of the exhaust gas flowing through the bypass passage;
A target supercharging pressure setting unit that sets a target supercharging pressure of the turbocharger, which is required to realize the target output torque of the engine acquired based on the operating state of the engine;
A waste gate that sets the target waste gate valve opening required to realize the target boost pressure and controls the valve opening of the waste gate valve so as to realize the target waste gate valve opening. A valve control unit,
In the purge increase control, the increase execution unit increases the boost pressure by setting a boost pressure equal to or higher than the target boost pressure set by the target boost pressure setting unit as a target value. An engine control device. The engine control device according to any one of claims 1 to 3 ,
An engine control device, wherein an air release pipe for opening the canister to the atmosphere is connected to the canister.

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