CN115698492A - Control devices for internal combustion engines - Google Patents

Abstract

The control device 100 includes: a supercharging control unit 124, which controls the opening of the intake throttle valve 28 and the turbocharger 40 arranged in the intake passage, and controls the supercharging pressure of the air flowing to the main body of the internal combustion engine; The unit 122 sets a part of the supercharger FF region where the turbocharger 40 performs feed-forward control of the supercharging pressure in the control region defined by the engine main body rotational speed and the fuel injection amount to make the intake throttle valve 28 A valve FB area for feedback control; and a mode determination unit 123 , which determines whether or not a temperature increase control mode for increasing the temperature of the post-processing device that purifies exhaust gas generated from the engine main body is being executed. When it is determined that the temperature rise control mode is being executed, the supercharging control unit 124 causes the intake throttle valve 28 to perform feedback control within the valve FB area set by the control area setting unit 122 .

Description

Control devices for internal combustion engines

technical field

The invention relates to a control device for an internal combustion engine.

Background technique

In an internal combustion engine, the supercharging pressure of intake air flowing into the main body of the internal combustion engine is adjusted by controlling the opening of a valve or a supercharger provided in an intake passage.

In addition, an internal combustion engine is provided with a post-processing device (for example, a catalyst) for purifying exhaust gas, and in order to activate the catalyst, a temperature rise control mode is executed to raise the temperature of the catalyst. In the warming control mode with little fresh air, since the control performance of the supercharging pressure by the valve is higher than the control performance of the supercharging pressure by the supercharger, the feedback control by the valve is performed.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2009-79557.

Contents of the invention

The problem to be solved by the invention

However, the control region where the valve performs feedback control is the same as the control region where the supercharger performs feedforward control. In this case, since there is a region that is not suitable as a control region for feedback control of the valve (the controllability of the valve is different from that of the supercharger), feedback control of the valve may not be performed with high accuracy.

Therefore, the present invention has been made in view of these problems, and an object of the present invention is to perform feedback control of the valve with high accuracy in the temperature rise control mode.

means of solving problems

One aspect of the present invention provides a control device for an internal combustion engine, comprising: a supercharging control unit for controlling the opening of a valve and a supercharger provided in an intake passage, and controlling the supercharging pressure of air flowing to the main body of the internal combustion engine; The region setting unit sets a part of the supercharger FF region in which the supercharger performs feed-forward control of the supercharging pressure in the control region defined by the rotation speed of the engine main body and the fuel injection amount so that a valve FB area where the valve is feedback-controlled; and a mode determination section that determines whether or not a temperature increase control mode for increasing the temperature of an after-treatment device that purifies exhaust gas generated from the engine main body is being executed, wherein, in passing When the mode determination unit determines that the temperature rise control mode is being executed, the pressure increase control unit performs feedback control of the valve within the valve FB region set by the control region setting unit.

In addition, the control region setting unit may set a region in which the fuel injection amount is equal to or greater than the first injection amount and equal to or less than the second injection amount in the supercharger FF region as the valve FB region.

In addition, the control region setting unit may set, in the supercharger FF region, a region in which the rotation speed is not less than a first rotation speed and not more than a second rotation speed, as the valve FB region.

In addition, when it is determined by the mode determination unit that the temperature increase control mode is being executed, the supercharging control unit may set the supercharger in the supercharger FF region except the Feedforward control is performed in areas other than the valve FB area.

In addition, the control region setting unit may set a region in which the rotational speed is equal to or less than a predetermined number in the control region as the valve FB region, and when it is determined by the mode determination unit that the temperature increase is being performed, control mode, and when the rotational speed is greater than the predetermined number, the supercharging control unit may cause the supercharger to perform feedback control.

In addition, the mode determination unit may determine whether it is the temperature increase control mode based on the temperature of cooling water for cooling the internal combustion engine and the temperature of the exhaust gas.

Invention effect

According to the present invention, there is an effect that feedback control of the valve can be performed with high accuracy in the temperature increase control mode.

Description of drawings

FIG. 1 is a schematic diagram for explaining the structure of an internal combustion engine 1 according to one embodiment.

FIG. 2 is a schematic diagram for explaining the valve FB region in the temperature increase control mode.

FIG. 3 is a schematic diagram illustrating a detailed configuration of the control device 100 .

FIG. 4 is a schematic diagram for explaining an example of setting of the valve FB area in the temperature increase control mode.

Detailed ways

<Structure of internal combustion engine>

The structure of an internal combustion engine according to one embodiment of the present invention will be described with reference to FIG. 1 .

FIG. 1 is a schematic diagram for explaining the structure of an internal combustion engine 1 according to one embodiment. The internal combustion engine 1 is, for example, a multi-cylinder engine mounted on a vehicle such as a truck. The internal combustion engine 1 is a diesel engine, but is not limited thereto, and may be a gasoline engine, for example. As shown in FIG. 1 , the internal combustion engine 1 has an engine body 10 , a fuel injection device 15 , an intake passage 20 , an exhaust passage 30 , a turbocharger 40 , an EGR device 50 , and a control device 100 .

Herein, the engine body 10 has four cylinders 12, but is not limited thereto. Movable members such as a piston and a crankshaft are provided in each cylinder 12 .

The fuel injection device 15 is an injection device that injects fuel into a combustion chamber inside the engine main body 10 . Herein, the fuel injection device 15 is a common rail type fuel injection device having an injector 16 and a common rail 17 . An injector 16 injects fuel into a combustion chamber within each cylinder 12 . The common rail 17 stores fuel injected from the injector 16 in a high-pressure state.

The intake passage 20 is a passage through which intake air sucked into the engine body 10 flows. The intake passage 20 has an intake manifold 22 connected to the engine body 10 and an intake pipe 23 connected to an upstream end of the intake manifold 22 . The intake manifold 22 distributes and supplies the intake air sent from the intake pipe 23 to the intake ports of the respective cylinders. An air cleaner 24 , an air flow meter 25 , a compressor 42C of the turbocharger 40 , an intercooler 27 , and an intake throttle valve 28 are provided in the intake pipe 23 . The air flow meter 25 detects the amount of intake air per unit time of the internal combustion engine 1 , that is, the intake air flow rate. The intake throttle valve 28 can be rotated to adjust the opening degree, for example.

The exhaust passage 30 is a passage through which exhaust gas generated from the engine body 10 flows. The exhaust passage 30 has an exhaust manifold 32 connected to the engine body 10 and an exhaust pipe 33 connected to the downstream end of the exhaust manifold 32 . The exhaust manifold 32 collects the exhaust gases sent from the exhaust ports of the respective cylinders. A turbine 42T of a turbocharger 40 and an aftertreatment device 35 are provided in the exhaust pipe 33 . The post-processing device 35 is a device for purifying exhaust gas, and includes, for example, an oxidation catalyst, DPF, SCR, and ammonia oxidation catalyst.

However, during the period from the cold start of the internal combustion engine 1 to the end of the warm-up, a control mode for early raising the temperature of the aftertreatment device 35 (specifically, the catalyst) (hereinafter referred to as a temperature raising control mode) can be executed. In the temperature rise control mode, the intake of fresh air is reduced, and the recirculation amount of exhaust gas by the EGR device 50 is increased. Therefore, the characteristics of the intake and exhaust in the temperature increase control mode are different from those in the normal control modes other than the temperature increase control mode.

The turbocharger 40 is a supercharger that compresses intake air flowing in the intake passage 20 using the flow of exhaust gas flowing in the exhaust passage 30 . The turbocharger 40 has a turbine 42T provided in the exhaust passage 30 and a compressor 42C provided in the intake passage 20 . The turbine 42T has a valve whose opening can be controlled. The compressor 42C rotates in conjunction with the rotation of the turbine 42T, and compresses intake air.

The EGR device 50 returns a part of the exhaust gas to the engine main body 10 . Specifically, the EGR device 50 returns a part of the exhaust gas (hereinafter referred to as EGR gas) in the exhaust passage 30 (herein, the exhaust manifold 32 ) into the intake passage 20 (herein, the intake manifold 32 ). 22). The EGR device 50 has an EGR passage 52 , an EGR cooler 53 , an EGR valve 54 , and a temperature sensor 55 .

The EGR passage 52 is a channel through which EGR gas flows. The EGR cooler 53 is provided in the EGR passage 52 and cools EGR gas. The EGR valve 54 is an openable and closable valve, and adjusts the flow rate of EGR gas. The temperature sensor 55 detects the temperature of the EGR gas flowing in the EGR passage 52 .

The control device 100 controls the operation of the internal combustion engine 1 as a whole. The control device 100 controls the opening degrees of the turbocharger 40 and the intake throttle valve 28 to perform supercharging control for controlling the supercharging pressure of the air flowing to the engine main body 10 . For example, as supercharging control, the control device 100 performs feedforward control or feedback control by the turbocharger 40 , or performs feedback control by the intake throttle valve 28 .

In addition, the control device 100 performs feedback control by the intake throttle valve 28 or feedback control by the turbocharger 40 in the above-mentioned temperature increase control mode. For example, the control device 100 performs feedback control of the intake throttle valve 28 when the rotational speed of the engine main body 10 is low, and performs feedback control of the turbocharger 40 when the rotational speed of the engine main body 10 is high.

In the present embodiment, the control device 100 sets a region in which the feedback control of the intake throttle valve 28 is performed (hereinafter referred to as a valve FB region) to be narrow, and the details will be described later. This prevents the air intake throttle valve 28 from being operated in a region with poor controllability, so that the feedback control of the air intake throttle valve 28 in the temperature rise control mode can be performed with high precision.

FIG. 2 is a schematic diagram for explaining the valve FB region in the temperature increase control mode. FIG. 2( a ) shows the valve FB region according to the comparative example, and FIG. 2( b ) shows the valve FB region according to the present embodiment. 2( a ) and FIG. 2( b ) show the region R1 in which the temperature increase control mode is executed, the turbocharger 40 in the temperature increase control mode, which is a region where the feedforward control of the turbocharger 40 is performed, that is, the turbine FF region R2 and the valve FB region. R3. In the comparative example shown in FIG. 2( a ), the turbine FF region R2 and the valve FB region R3 overlap. In this case, the valve FB region R3 includes a control region (a region with poor controllability) that is not suitable for feedback control of the intake throttle valve 28 . In contrast, in the present embodiment shown in FIG. 2( b ), the valve FB region R3 is a part of the turbine FF region R2 and includes only a control region suitable for feedback control of the intake throttle valve 28 (control good areas).

<Detailed structure of the control unit>

The detailed configuration of the control device 100 will be described with reference to FIG. 2 .

FIG. 3 is a schematic diagram illustrating a detailed configuration of the control device 100 . The control device 100 has a storage unit 110 and a control unit 120 .

The storage unit 110 includes, for example, ROM (Read Only Memory, Read Only Memory) and RAM (Random Access Memory, Random Access Memory). The storage unit 110 stores programs executed by the control unit 120 and various data.

The control unit 120 is, for example, a CPU (Central Processing Unit, central processing unit). The control section 120 controls the operation of the internal combustion engine 1 by executing programs stored in the storage section 110 . In the present embodiment, the control unit 120 functions as a control region setting unit 122 , a mode determination unit 123 , and a boost control unit 124 .

The control region setting unit 122 sets a region for controlling the intake throttle valve 28 . The control region setting unit 122 sets a control region based on the rotation speed of the engine main body 10 and the fuel injection amount detected by the detection sensor group 70 . For example, the control region setting unit 122 sets a valve FB region in which the air intake throttle valve 28 is feedback-controlled in the temperature rise control mode. The control region setting unit 122 sets a part of the turbo FF region (supercharger FF region) in which the turbocharger 40 is subjected to feedforward control in the control region as the valve FB in which the intake throttle valve 28 is subjected to feedback control. area.

FIG. 4 is a schematic diagram for explaining an example of setting of the valve FB area in the temperature increase control mode. In FIG. 4 , the horizontal axis represents the rotational speed of the engine main body 10 , and the vertical axis represents the fuel injection amount. A region enclosed by a dotted line is a turbine FF region R2, and a hatched region is a valve FB region R3. The valve FB region R3 set by the control region setting unit 122 is a region in which the fuel injection amount is not less than the first injection amount A1 and not more than the second injection amount A2 in the turbo FF region R2. In addition, the valve FB region R3 is a region in which the rotation speed is not less than the first rotation speed C1 and not more than the second rotation speed C2. Also, although not shown in FIG. 4 , the region on the side larger than the second rotation speed C2 (ie, the region where the controllability of the intake throttle valve 28 is poor) is a region where the turbocharger 40 performs feedback control. In addition, the first injection amount A1 corresponds to the first threshold value, and the second injection amount A2 corresponds to the second threshold value.

The mode determination unit 123 determines the control mode of the internal combustion engine 1 . For example, the mode determination unit 123 determines whether or not the control mode is executing the temperature increase control mode. The temperature rise control mode is a control mode for advancing the temperature rise of the aftertreatment device 35 (specifically, the catalyst) during the period from the cold start of the internal combustion engine 1 to the completion of the warm-up.

The mode determination unit 123 determines the control mode based on the state of the internal combustion engine 1 detected by the detection sensor group 70 . The mode determination unit 123 can determine the control mode based on the temperature of the cooling water cooling the internal combustion engine 1 and the temperature of the exhaust gas. For example, the mode determination unit 123 determines that it is the temperature increase control mode when the temperature of the cooling water and the temperature of the exhaust gas are respectively higher than predetermined values, and when the temperature of the cooling water and the temperature of the exhaust gas are respectively lower than the predetermined values , it is judged as normal control mode. In addition, the mode determination unit 123 may perform determination including other parameters (for example, atmospheric pressure) in addition to the temperature of the cooling water and the temperature of the exhaust gas.

The supercharging control unit 124 performs supercharging control of intake air. The boost control unit 124 controls the openings of the intake throttle valve 28 provided in the intake passage 20 and the turbocharger 40 (specifically, the valve of the turbine 42T), and controls the boost pressure of air flowing into the engine body 10 .

The pressure increase control unit 124 performs pressure increase control, for example, in the temperature increase control mode. Normally, the turbocharger 40 is excellent in the controllability of the intake air amount at a large flow rate, and the intake throttle valve 28 is excellent in the controllability of the intake air amount at a small flow rate. Therefore, in the temperature increase control mode, the supercharging control unit 124 performs feedback control of the intake throttle valve 28 when the rotational speed of the engine main body 10 is low (that is, when the amount of intake air is small). On the other hand, in the temperature increase control mode, the supercharging control unit 124 performs feedback control of the turbocharger 40 when the rotational speed of the engine main body 10 is high (that is, when the amount of intake air is large).

In the temperature rise control mode, the supercharging control unit 124 performs feedback control on the intake throttle valve 28 in the valve FB region which is a part of the turbo FF region. That is, when the mode determination unit 123 determines that the temperature rise control mode is being executed, the supercharging control unit 124 causes the intake throttle valve 28 to perform feedback control within the valve FB region set by the control region setting unit 122 . Accordingly, the intake throttle valve 28 can be feedback-controlled in a region with good controllability. In addition, the boost control unit 124 may perform the feedforward control by the turbocharger 40 in a region other than the valve FB region in the turbo FF region.

When it is determined by the mode determination unit 123 that the temperature increase control mode is being executed and the rotational speed is higher than a predetermined number (the second rotational speed C2 shown in FIG. 4 ), the boost control unit 124 causes the turbocharger 40 to perform feedback control. That is, the supercharging control unit 124 does not perform supercharging control by the intake throttle valve 28 , but performs supercharging control by the turbocharger 40 . As a result, the turbocharger 40 can appropriately perform supercharging control in a region where the controllability of the intake throttle valve 28 is poor.

<Effects of this embodiment>

The control device 100 of the internal combustion engine 1 in the above-described embodiment sets a part of the turbo FF region in which the turbocharger 40 is subjected to feedforward control as the valve FB region in which the intake throttle valve 28 is subjected to feedback control. Then, in the temperature rise control mode, the control device 100 performs feedback control of the air intake throttle valve 28 within the set valve FB region.

Thus, by limiting the region where the intake throttle valve 28 is feedback-controlled to, for example, a low-load, low-rotation region, control of the intake throttle valve 28 in a region with poor controllability can be suppressed. Therefore, the feedback control of the air intake throttle valve 28 can be performed with higher precision.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range described in said embodiment, Various deformation|transformation and changes are possible within the range of the summary. For example, all or a part of the devices may be functionally or physically dispersed and combined in arbitrary units. In addition, new embodiments obtained by arbitrary combinations of the plurality of embodiments are also included in the embodiments of the present invention. The effect of the new embodiment produced by combination also has the effect of the original embodiment.

reference sign

1 internal combustion engine

20 intake passage

28 intake throttle valve

35 post-processing device

40 Turbo

100 control device

122 Control area setting part

123 Mode Judgment Unit

124 Supercharging control department

Claims (6)

1. A control device for an internal combustion engine, comprising:

a supercharging control unit that controls the opening degree of a valve and a supercharger provided in an intake passage and controls the supercharging pressure of air flowing into an engine main body;

a control region setting unit that sets a partial region of a supercharger FF region in which the supercharger performs feed-forward control of the supercharging pressure in a control region defined by the rotation speed and the fuel injection amount of the engine main body as a valve FB region in which the valve performs feedback control; and

a mode determination unit that determines whether or not a temperature rise control mode for raising a temperature of an aftertreatment device that purifies exhaust gas generated from the engine body is being executed,

the pressure-increasing control portion causes the valve to perform feedback control in the valve FB region set by the control region setting portion, in a case where it is determined by the mode determination portion that the temperature raising control mode is being executed.

2. The control device of an internal combustion engine according to claim 1,

the control region setting unit sets a region in which the fuel injection amount is equal to or greater than a first injection amount and equal to or less than a second injection amount in the supercharger FF region as the valve FB region.

3. The control device of an internal combustion engine according to claim 1 or 2, wherein,

the control region setting unit sets a region in which the rotation speed is equal to or higher than a first rotation speed and equal to or lower than a second rotation speed in the supercharger FF region as the valve FB region.

4. The control device of an internal combustion engine according to any one of claims 1 to 3, wherein,

the boost control portion causes the supercharger to perform feed-forward control in a region other than the valve FB region among the supercharger FF region in a case where it is determined by the mode determination portion that the temperature-raising control mode is being executed.

5. The control device of an internal combustion engine according to any one of claims 1 to 4,

the control region setting unit sets a region in the control region where the number of rotations is equal to or less than a predetermined number as the valve FB region,

the supercharging control unit causes the supercharger to perform feedback control when the mode determination unit determines that the temperature increase control mode is being executed and the rotation speed is greater than the predetermined number.

6. The control device of an internal combustion engine according to any one of claims 1 to 5,

the mode determination portion determines whether the temperature-raising control mode is in accordance with a temperature of cooling water that cools the internal combustion engine and a temperature of the exhaust gas.

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