JP2018048588A - Electronic control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a turbo lag without differently installing an auxiliary device or the like to a system of an internal combustion engine having a general supercharger.SOLUTION: An ECU 4 controls an engine 2 with a turbocharger 3, and comprises a supercharge state determination part 14 for determining whether or not the engine is in a supercharged state, an accelerator-off determination part 15 for determining whether or not an accelerator is in an accelerator-off state, and an alleviation processing part 16. When a first condition that the supercharged state is determined by the supercharge state determination part 14, and a second condition that the accelerator-off state is determined by the accelerator-off determination part 15 are satisfied, the alleviation processing part 16 performs stop processing for stopping the generation of a drive force by the engine 2, throttle valve opening processing for controlling a throttle valve 9 to an opening direction, and gate valve closing processing for controlling a waste gate valve 13 to a closing direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic control device for controlling an internal combustion engine with a supercharger.

  Conventionally, a technique for reducing turbo lag in an internal combustion engine with a supercharger has been considered. For example, Patent Document 1 discloses a configuration in which compressed air stored in an air reservoir tank is blown to an exhaust-side rotor blade of a turbocharger and compressed air is blown into an intake pipe. According to such a configuration, the rotational speed of the turbocharger that has decreased due to the accelerator off or the like increases instantaneously, and as a result, the turbo lag is eliminated.

JP 2006-258082 A

  However, in the above prior art, auxiliary devices such as a compressor, an air reservoir tank, and an open / close valve need to be provided separately, which causes problems such as an increase in cost and an increase in weight. Further, depending on the size of the engine room, there may be a case where a space for providing the auxiliary device cannot be secured. In such a case, the above-described conventional technique cannot be employed.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic device capable of reducing turbo lag without separately providing an auxiliary device or the like for a general supercharger-equipped internal combustion engine system. It is to provide a control device.

  The electronic control device according to claim 1 controls an internal combustion engine (2) with a supercharger (3), and determines whether or not it is in a supercharged state. And an accelerator-off determining unit (15) that determines whether or not the accelerator is off, and a reduction processing unit (16, 24). When the first condition that the supercharging state determination unit determines that the engine is in the supercharging state and the second condition that the accelerator off determination unit determines that the accelerator is off are satisfied, the reduction processing unit A stop process for stopping the generation of the driving force, a throttle valve opening process for controlling the throttle valve (9) to open, and a gate valve closing process for controlling the waste gate valve (13) are performed.

  According to such a configuration, when the accelerator is turned off from the supercharged state, generation of driving force by the internal combustion engine is stopped and the throttle valve is opened. Thus, since the throttle valve is not closed, the air pumped by the supercharger does not flow backward. In the above configuration, the waste gate valve is closed when the accelerator is turned off from the supercharged state. Therefore, even after the accelerator is turned off, air flows into the supercharger, and the decrease in the rotational speed of the supercharger becomes gentler than in the conventional control in which the throttle valve is closed.

  Therefore, according to the above configuration, it is possible to reduce the turbo lag without separately providing an auxiliary device or the like for a general supercharged internal combustion engine system. For this reason, problems such as an increase in cost and weight do not occur, and it can be applied to a vehicle in an engine room in which only a space sufficient to provide an auxiliary device or the like can be secured. Become.

The figure which shows typically the structure of the engine system which concerns on 1st Embodiment. The figure which shows the flow of engine control by ECU typically Timing chart schematically showing the operating state of each part when the accelerator is off from the supercharged state The figure which shows typically the operation state of each part at the time of accelerator off from the supercharging state which concerns on conventional control, and the flow of air The figure which shows typically the operation state of each part at the time of the accelerator off from the supercharging state which concerns on this embodiment, and the flow of air Diagram showing the relationship between intake air volume and throttle opening The figure which shows the structure of the engine system which concerns on 2nd Embodiment typically. The figure which shows the flow of engine control by ECU typically

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In each embodiment, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  An engine system 1 shown in FIG. 1 is mounted on a vehicle such as an automobile. The engine system 1 includes an engine 2 that is an internal combustion engine such as a gasoline engine or a diesel engine, a turbocharger 3 that is a supercharger, an ECU (Electronic Control Unit) 4 that is an electronic control device that controls the engine 2, and the like. Is done. In FIG. 2, the air flow is indicated by a dashed arrow, and the data flow, that is, the input / output direction of an electric signal is indicated by a solid arrow.

  The engine 2 is connected to an intake passage 5 that sucks air from the outside of the vehicle and an exhaust passage 6 that exhausts air to the outside of the vehicle. The intake passage 5 is provided with an air flow meter 7 corresponding to an intake air amount detection unit that detects an intake air amount. A signal of the intake air amount detected by the air flow meter 7 is input to the ECU 4.

  The compressor side of the turbocharger 3 is connected to the downstream side of the air flow meter 7 in the intake passage 5. Although not shown in detail, the turbocharger 3 is configured by installing a turbine on one end side of a rotating shaft and a compressor on the other end side as is well known. Thus, the turbine is rotated using the exhaust gas from the engine 2, and the compressor is driven by the turbine to compress the air taken into the intake passage 5.

  The intake passage 5 is provided with an intercooler 8 that is located downstream of the turbocharger 3 and cools the compressed air. Further, a throttle valve 9 and a surge tank 10 are provided in this order on the downstream side of the intercooler 8. The surge tank 10 is provided with a tank internal pressure sensor 11 for detecting the internal pressure of the surge tank 10. The surge tank internal pressure signal detected by the tank internal pressure sensor 11 is input to the ECU 4. The opening / closing of the throttle valve 9 is controlled by the ECU 4.

  On the other hand, the turbine side of the turbocharger 3 is connected to the exhaust passage 6. The exhaust passage 6 is provided with a bypass passage 12 that bypasses the turbocharger 3, and a waste gate valve 13 (hereinafter abbreviated as WGV 13) for opening and closing the bypass passage 12. . When the WGV 13 is opened, the exhaust from the engine 2 is performed through the bypass 12 without passing through the turbocharger 3. On the other hand, the turbocharger 3 is driven in a state where the WGV 13 is closed. The opening / closing of the WGV 13 is controlled by the ECU 4.

  The ECU 4 is mainly composed of a microcomputer having a CPU, a ROM, a RAM, and the like. The ECU 4 executes various controls for controlling the engine system 1 by executing a computer program stored in a ROM or the like by the CPU.

  The ECU 4 receives an accelerator opening signal and an engine speed signal. The ECU 4 controls an igniter (not shown), an opening control of the throttle valve 9 and an opening / closing of the WGV 13 based on these signals. Control, and further, control of an automatic transmission (not shown) are executed.

  The ECU 4 also includes a supercharge state determination unit 14, an accelerator off determination unit 15, and a reduction processing unit 16. The supercharging state determination unit 14, the accelerator-off determination unit 15, and the mitigation processing unit 16 are realized in software by a computer program executed by the CPU.

  The supercharging state determination part 14 determines whether it is a supercharging state. Specifically, when the supercharging state determination unit 14 detects that the internal pressure of the surge tank detected by the tank internal pressure sensor 11 is equal to or higher than the atmospheric pressure regardless of the open / closed state of the WGV 13, the supercharging state, That is, it determines with supercharging.

  The accelerator off determination unit 15 determines whether or not the accelerator is off. Specifically, based on the accelerator opening signal given from the accelerator pedal, when the accelerator opening is zero, that is, when “accelerator opening = 0%”, it is determined that the accelerator is off. When the opening is larger than zero, that is, when “accelerator opening> 0%”, it is determined that the accelerator is not off, that is, the accelerator is on.

  The reduction processing unit 16 executes various processes for reducing turbo lag. Specifically, when the first condition and the second condition are satisfied, the reduction processing unit 16 performs a stop process for stopping the generation of driving force by the engine 2 and a throttle valve opening process for controlling the throttle valve 9 to open. And a gate valve closing process for controlling the WGV 13 in the closing direction.

  Here, the first condition is a condition that the supercharging state determination unit 14 determines that the state is the supercharging state, and the second condition is a condition that the accelerator off determination unit 15 determines that the accelerator is off. It is. Further, in the stop process, the generation of driving force by the engine 2 is stopped by cutting fuel injection and ignition to the engine 2.

Next, the flow of control of the engine 2 by the ECU 4 will be described with reference to FIG.
As shown in FIG. 2, in step S101, the supercharging state determination unit 14 determines whether or not supercharging is being performed. If supercharging is being performed, that is, if “YES” in the step S101, the process proceeds to a step S102. In step S102, the accelerator-off determining unit 15 determines whether or not the accelerator is off.

  Here, when the accelerator is off, it can be determined that the driver does not intend to accelerate. Therefore, if “YES” in the step S102, the process proceeds to a step S103, and a stop process for eliminating the driving force of the engine 2 is executed by the reduction processing unit 16. After execution of step S103, the process proceeds to step S104, and a throttle valve opening process is executed by the reduction processing unit 16 to control the throttle valve 9 to open. In the throttle valve opening process of the present embodiment, the opening of the throttle valve 9 is controlled to be “fully open”.

  After execution of step S104, the process proceeds to step S105, and a gate valve closing process for controlling the WGV 13 in the closing direction is executed by the reduction processing unit 16. In the gate valve closing process of the present embodiment, the opening degree of the WGV 13 is controlled to be “fully closed”. On the other hand, if “NO” in step S101 or S102, the process proceeds to step S106 without performing the processes S103 to S105 by the reduction processing unit 16 described above, and normal control (normal control) is performed.

Next, the operation of the above configuration will be described.
FIG. 3 is a timing chart showing the operation state of each part. For comparison with the present embodiment, the operation state of each part in conventional control (hereinafter referred to as conventional control) in which turbo lag reduction processing is not performed is indicated by a broken line. ing. As shown in FIG. 3, in the supercharging state before time t1, the accelerator is “ON” (accelerator on), the supercharging pressure is “maximum supercharging pressure”, and the throttle is opened in both the present embodiment and the conventional control. The degree is a value corresponding to the intake air amount, the injection ignition permission is “ON”, and the WGV is “fully closed”.

  When the accelerator is turned off from the supercharged state at time t1, the injection ignition permission is first changed to “OFF” and the injection and ignition are cut. Thereby, the driving force by the engine 2 is not generated. Subsequently, the throttle valve 9 is controlled to be “fully open”. At this time, in the conventional control, the throttle valve 9 is controlled to be closed, specifically, to be “fully closed”. Due to these differences, “backflow” occurs in the conventional control, whereas “backflow” does not occur in the present embodiment. Hereinafter, the reason will be described with reference to FIG. 4 and FIG.

  As described above, in the case of the conventional control, when the accelerator is turned off from the supercharging state, the throttle valve 9 is closed. Therefore, as shown in FIG. 4, the air that has been pumped by the turbocharger 3 is squeezed by the throttle valve 9, and the air flows backward. On the other hand, in the case of the present embodiment, when the accelerator is turned off from the supercharged state, the throttle valve 9 is opened without being closed. Therefore, as shown in FIG. 5, the air pumped from the turbocharger 3 does not flow backward.

  Further, at the time t1, in the present embodiment, the WGV 13 is controlled to be “fully closed”. Note that the WGV is “fully closed” even before the time t1, and in this case, the WGV 13 is controlled to maintain the “fully closed” state. As a result, as shown in FIG. 5, the exhaust gas that has passed through the engine 2 whose injection and ignition have been cut flows into the turbocharger 3. For this reason, in this embodiment, the decrease in the supercharging pressure after the accelerator is turned off becomes gradual as compared with the conventional control.

  Thereafter, when the accelerator is turned on again at time t2 (accelerator: ON), the injection ignition permission is changed to “ON” and the supercharging pressure is controlled to increase toward the maximum supercharging pressure. At this time, in this embodiment, the backflow of the pressure-fed air is not generated because the throttle valve 9 is opened when the accelerator is off, and the supercharging pressure is reduced due to the WGV 13 being closed. Since it is gentler than the control, the supercharging pressure quickly increases and reaches the maximum supercharging pressure compared to the conventional control.

According to this embodiment described above, the following effects can be obtained.
In the conventional control, the throttle valve 9 is closed when the accelerator is off from the supercharging state. For this reason, when the accelerator is suddenly turned off during supercharging, the backflow of the air fed from the turbocharger 3 occurs. Further, since the exhaust gas does not flow into the turbocharger 3, the rotational speed of the turbocharger 3 decreases. For this reason, when the accelerator is turned on again, the inflow of air into the engine 2 is hindered by the backflowed air, which may cause a deterioration in response.

  On the other hand, in this embodiment, generation | occurrence | production of the said problem is prevented by adding a device to the control content of ECU4. That is, according to the present embodiment, when the accelerator is turned off from the supercharged state, generation of driving force by the engine 2 is stopped and the throttle valve 9 is opened. Therefore, in this embodiment, the backflow of the air pumped by the turbocharger 3 can be prevented.

  In the present embodiment, the WGV 13 is closed when the accelerator is turned off from the supercharged state. Therefore, air flows into the turbocharger 3 even after the accelerator is turned off, and the decrease in the rotational speed of the turbocharger 3 is moderate as compared with the conventional control. Therefore, when the accelerator is turned on again, the supercharging pressure rises more quickly than in the conventional control, and the turbo lag is reduced.

  Therefore, according to this embodiment, it is possible to reduce the turbo lag without separately providing an auxiliary device or the like for a general supercharger-equipped internal combustion engine system. Therefore, there is no problem of an increase in cost and an increase in weight, and the present invention can also be applied to a vehicle in an engine room in which only a space that cannot provide an auxiliary device or the like can be secured.

  In the throttle valve opening process, the reduction processing unit 16 controls the opening degree of the throttle valve 9 to “fully open”. In this way, when the accelerator is off from the supercharged state, it is possible to reliably prevent the flow of air pumped from the turbocharger 3 from being obstructed by the throttle valve 9, and as a result, the occurrence of backflow can be further reduced. It can be surely prevented.

  Note that the reduction processing unit 16 may change the opening degree of the throttle valve 9 so as to control the opening degree according to the amount of intake air from the outside in the throttle valve opening process. That is, as shown in FIG. 6, the throttle opening is generally determined by the intake air amount. Basically, by setting the throttle opening to increase as the intake air amount increases, the flow of the intake air is not hindered.

  Therefore, in the throttle valve opening process, the opening degree of the throttle valve 9 may be controlled so as to obtain an optimum throttle opening degree with respect to the intake air amount detected by the air flow meter 7. The “optimum throttle opening” here is the minimum opening that does not hinder the flow of the intake air.

  In this way, when the rotational speed of the turbocharger 3 decreases for a while after the accelerator is turned off and the intake air amount decreases, the throttle opening also decreases accordingly. From this state, when the accelerator is depressed again and the accelerator is turned on, re-acceleration is performed from the state where the throttle opening is the optimum throttle opening with respect to the intake air amount at that time. Become. Therefore, acceleration as intended by the driver is performed, and the vehicle behavior at the time of reacceleration is good without any sense of incongruity.

  The reduction processing unit 16 controls the opening of the WGV 13 to “fully closed” in the gate valve closing processing. In this way, when the accelerator is off from the supercharged state, the exhaust gas that has passed through the engine 2 can surely flow into the turbocharger 3. As a result, the decrease in the supercharging pressure after the accelerator is off is moderated. An effect can be obtained with certainty.

  In general, the WGV 13 is controlled so as to be closed during a period in which it is in a supercharged state and to be opened in a period in which it is not in a supercharged state. May be performed. However, the control of the present embodiment assumes a situation where air can flow backward when the accelerator is off. Therefore, when the above determination is made based on the open / closed state of the WGV 13, it is possible to determine that the supercharged state is present even in a situation where the air does not flow backward, such as when the WGV 13 is closed but the turbocharger 3 is not sufficiently rotated. There is sex. For this reason, the above determination based on the open / closed state of the WGV 13 is not suitable for the control of the present embodiment.

  Therefore, the supercharging state determination unit 14 determines that the supercharging state is detected when it is detected that the internal pressure of the surge tank 10 is equal to or higher than the atmospheric pressure regardless of the open / closed state of the WGV 13. In this way, it is possible to reliably determine whether or not the engine is in the supercharging state even when performing the control of the present embodiment.

  The accelerator-off determining unit 15 determines that the accelerator is off when the accelerator opening is zero, and determines that the accelerator is not off when the accelerator opening is greater than zero. Thus, the reason for adopting zero (0%) as the accelerator-off determination threshold is as follows.

  That is, for example, when the vehicle is traveling at high speed, there is a case where the driver tries to maintain the current traveling speed by stepping on the accelerator pedal slightly. In such a case, if a small value other than 0%, for example, several percent, is used as the accelerator-off determination threshold, the following problem occurs.

  That is, in this case, there is a possibility that the driver erroneously determines that the accelerator is off, although the driver intentionally steps on the accelerator (accelerator is on). If it does so, the process after step S103 will be implemented contrary to a driver | operator's intention, the driving force of the engine 2 will not generate | occur | produce, and the driving speed of a vehicle will fall (decelerate).

  As a result, the behavior of the vehicle is not as intended by the driver, and the driver feels uncomfortable. On the other hand, if zero is adopted as the accelerator-off determination threshold as in this embodiment, there is no possibility of erroneous determination that the accelerator is off even in the above-described case, and there is a possibility of giving the driver a sense of discomfort. It can be kept low.

  In this embodiment, unlike the conventional control, since the throttle valve 9 is controlled to open when the accelerator is off from the supercharged state, the engine brake does not work, but this is a problem. There is nothing. This is because, in this embodiment, especially when the vehicle is traveling at high speed, it is assumed that the driver lifts his / her foot from the accelerator pedal for a short time and then steps on the accelerator pedal again. It is intended to.

  In such a situation, the driver does not expect deceleration by the engine brake in the first place, and the driver is not greatly decelerated originally by the engine brake. Therefore, as in this embodiment, even if the engine brake does not work by controlling the throttle valve 9 to open when the accelerator is off from the supercharged state, no problem occurs. It can be said that the one that does not work is the vehicle behavior as intended by the driver.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to FIGS. 7 and 8.
As shown in FIG. 7, the ECU 22 of the engine system 21 of the present embodiment is further provided with a brake-off determination unit 23 with respect to the ECU 4 of the first embodiment, and a reduction processing unit instead of the reduction processing unit 16. 24 is different. The brake-off determination unit 23 and the reduction processing unit 24 are realized by software, similar to the supercharging state determination unit 14 and the like.

  The brake off determination unit 23 determines whether or not the brake is off based on an electrical signal given from the brake pedal. When the third condition is satisfied in addition to the first condition and the second condition, the reduction processing unit 24 performs a stop process, a throttle valve opening process, and a gate valve closing process. Here, the third condition is a condition that the brake-off determination unit 23 determines that the brake is off.

Next, the flow of control of the engine 2 by the ECU 22 will be described with reference to FIG.
As shown in FIG. 8, step S201 is added to the control of this embodiment with respect to the control of 1st Embodiment. In this case, if it is determined in step S102 that the accelerator is off, that is, if “YES” in step S102, the process proceeds to step S201.

  In step S201, the brake-off determination unit 23 determines whether the brake is off. Here, if the brake is off, that is, if “YES” in the step S201, the processes after the step S103 (stop process, throttle valve opening process, and gate valve closing process) are performed. On the other hand, if the brake is not off, that is, if “NO” in the step S201, the process proceeds to the step S106 without performing the processes after the step S103, and the normal control is performed.

  Also by this embodiment described above, the same operations and effects as those of the first embodiment can be obtained. Further, in the present embodiment, as a condition for executing the processing of steps S103 to S105 for reducing turbo lag (hereinafter referred to as turbo lag reduction processing), the third condition that the brake is off is added. doing. Thereby, according to this embodiment, the following effects are also acquired.

  That is, in the control of the first embodiment, the turbo lag mitigation process is performed even when the brake is stepped on by the driver when the accelerator is off from the supercharged state. At this time, since the throttle valve 9 is opened, there is a possibility that the negative pressure is not generated, and that the degree of braking, that is, the braking force is reduced.

  On the other hand, if the brake-off determination is added as in the present embodiment, the turbo lag reduction process is executed only when the driver is not stepping on the brake when the accelerator is off from the supercharged state. In other words, even when the accelerator is off from the supercharged state, when the brake is not off, that is, when the brake is stepped on, priority is given to braking by the brake, and normal control is performed without performing turbo lag mitigation processing. Is implemented.

  In this way, when the driver is stepping on the brake, that is, when an operation intended for deceleration is performed, braking is prioritized reflecting the intention. Therefore, according to the present embodiment, it is possible to eliminate as much as possible that the vehicle behavior shows a behavior different from the behavior intended by the driver, thereby giving the driver an uncomfortable feeling.

(Other embodiments)
In addition, this invention is not limited to each embodiment described above and described in drawing, In the range which does not deviate from the summary, it can change, combine or expand arbitrarily.
In the control flow shown in FIG. 2 and FIG. 7, step S105 (gate valve closing process) is executed after step S104 (throttle valve opening process), but step S105 is changed to step S103 (stop). You may change so that it may perform before a process.

  Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

  2 ... Engine, 3 ... Turbocharger, 4, 22 ... ECU, 9 ... Throttle valve, 10 ... Surge tank, 13 ... Wastegate valve, 14 ... Supercharge state determination unit, 15 ... Acceleration off determination unit, 16, 24 ... Reduction processing unit, 23... Brake off determination unit.

Claims (7)

An electronic control device (4, 22) for controlling an internal combustion engine (2) with a supercharger (3),
A supercharging state determination unit (14) for determining whether or not a supercharging state;
An accelerator-off determining unit (15) for determining whether or not the accelerator is off;
When the first condition that the supercharging state determining unit determines that the engine is in the supercharging state and the second condition that the accelerator off determining unit determines that the accelerator is off are satisfied, the driving force by the internal combustion engine Reduction processing unit for executing stop processing for stopping the generation of throttle valve, throttle valve opening processing for controlling the throttle valve (9) to open, and gate valve closing processing for controlling the waste gate valve (13) to close (16, 24),
An electronic control device comprising: Furthermore, a brake-off determination unit (23) for determining whether or not the brake is off is provided,
When the third condition that the brake-off determination unit determines that the brake is off is satisfied in addition to the first condition and the second condition, the reduction processing unit performs the stop process and the throttle valve opening process. The electronic control device according to claim 1, wherein the gate valve closing process is executed.   The electronic control device according to claim 1, wherein the reduction processing unit controls the opening degree of the throttle valve to be fully opened in the throttle valve opening process.   The electronic control device according to claim 1, wherein the reduction processing unit controls the opening degree of the throttle valve to an opening degree corresponding to an intake air amount from outside in the throttle valve opening process.   5. The electronic control device according to claim 1, wherein, in the gate valve closing process, the reduction processing unit controls the opening degree of the waste gate valve to be fully closed. 6.   The said supercharging state determination part determines that it is the said supercharging state, if it detects that the internal pressure of a surge tank (10) is more than atmospheric pressure irrespective of the opening / closing state of the said wastegate valve. The electronic control device according to any one of 1 to 5.   The accelerator off determination unit determines that the accelerator is off when the accelerator opening is zero, and determines that the accelerator is not off when the accelerator opening is greater than zero. The electronic control device according to claim 6.

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