JP7169113B2 - air supply system - Google Patents

Description

The present invention relates to air supply systems.

Conventionally, for example, as described in Patent Document 1, compressed air is supplied upstream of the catalyst in the exhaust passage of the engine, and the catalyst is warmed up by burning unburned fuel in the exhaust gas. ing. In US Pat. No. 5,400,004, a motor-assisted turbocharger is used to supply compressed air.

Japanese Patent Application Laid-Open No. 2005-016351

When a turbocharger or the like is used to supply air to the exhaust passage, the energy of the exhaust gas is consumed, which may reduce the efficiency of catalyst warm-up.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an air supply system capable of more efficiently warming up a catalyst.

In order to solve the above problems, the air supply system of the present invention provides a supercharger connected to the output shaft of the engine via a first clutch and connected to the output shaft of the motor via a second clutch. a first passage connected to the supercharger and communicating upstream of a catalyst that purifies the exhaust gas in the exhaust passage of the engine; a second passage connected to the supercharger and communicating with the intake passage of the engine; a switching mechanism for switching the discharge destination of the air compressed by the supercharger between the first passage and the second passage ; a switching control unit for controlling the switching mechanism so that the discharge destination is set to the first passage when the temperature of the catalyst is lower than the second temperature lower than the first temperature; and a clutch control unit that disconnects the first clutch and the second clutch to stop driving the supercharger when the temperature is two or more .
When the temperature of the catalyst is less than the first temperature and equal to or higher than the second temperature, the fuel control unit increases the amount of fuel injected in the engine compared to when the temperature of the catalyst is equal to or higher than the first temperature. At least one of an ignition control section may further be provided for retarding the ignition timing of the engine when the temperature is less than the first temperature and equal to or higher than the second temperature compared to when the temperature of the catalyst is equal to or higher than the first temperature.

The clutch control unit may control the first clutch and the second clutch based on at least one of the remaining capacity of a battery that supplies electric power to the motor and the thermal efficiency of the engine.

The clutch control unit engages the first clutch and disengages the second clutch when the remaining battery capacity is less than or equal to a predetermined threshold value, and when the remaining battery capacity is greater than the predetermined threshold value, the clutch control unit performs a clutch control based on the thermal efficiency of the engine. may be used to connect or disconnect the first clutch and the second clutch.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to perform a catalyst warm-up more efficiently.

It is a figure for demonstrating the schematic structure of an air supply system. It is a figure for demonstrating the control system of an air supply system. FIG. 4 is a diagram for explaining a normal mode; FIG. FIG. 4 is a diagram for explaining mode 0; FIG. 4 is a diagram for explaining mode 1; FIG. 10 is a diagram for explaining mode 2; 4 is a flowchart showing the flow of air supply processing;

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in these embodiments are merely examples for facilitating understanding of the invention, and do not limit the invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present invention are omitted from the drawings. do.

FIG. 1 is a diagram for explaining a schematic configuration of an air supply system 1. FIG. The air supply system 1 is mounted on a vehicle, for example. As shown in FIG. 1, the air supply system 1 has an engine 2 . An intake passage 4 including an intake manifold 3 (intake manifold) is connected to the engine 2 . Intake air flows into the engine 2 through an intake passage 4 .

An exhaust passage 5 including an exhaust manifold is connected to the engine 2 . Exhaust gas discharged from the engine 2 is discharged to an exhaust passage 5 . One end of an EGR passage 6 is connected to the exhaust passage 5 . The other end of the EGR passage 6 is connected to the intake manifold 3 . A part of the exhaust gas discharged to the exhaust passage 5 is recirculated to the intake manifold 3 through the EGR passage 6 .

A catalyst 7 is provided in the exhaust passage 5 downstream of a connection portion with the EGR passage 6 . The catalyst 7 is composed of, for example, a three-way catalyst or the like, and purifies exhaust gas when warmed up to an activation temperature.

The air supply system 1 is also provided with a supercharger 8 , a motor 9 and a battery 10 . A shaft 8 a of the supercharger 8 is connected to an output shaft 2 a of the engine 2 via a first clutch 11 . A shaft 8 b of the supercharger 8 is connected to an output shaft 9 a of the motor 9 via a second clutch 12 .

The first clutch 11 connects or disconnects the shaft 8 a of the supercharger 8 and the output shaft 2 a of the engine 2 . The second clutch 12 connects or disconnects the shaft 8 b of the supercharger 8 and the output shaft 9 a of the motor 9 .

When the first clutch 11 connects the shaft 8a of the supercharger 8 and the output shaft 2a of the engine 2, and the second clutch 12 disconnects the shaft 8b of the supercharger 8 and the output shaft 9a of the motor 9, , the supercharger 8 is driven by the power of the engine 2 (hereinafter referred to as the engine driving state).

When the second clutch 12 connects the shaft 8b of the supercharger 8 and the output shaft 9a of the motor 9, and the first clutch 11 disconnects the shaft 8a of the supercharger 8 and the output shaft 2a of the engine 2, , the supercharger 8 is driven by the power of the motor 9 driven by the electric power from the battery 10 (hereinafter referred to as the motor drive state).

The auxiliary intake passage 13 is connected to an intake port of the supercharger 8 . The auxiliary intake passage 13 may communicate with the intake passage 4 upstream, or may be provided independently of the intake passage 4 . When the supercharger 8 is driven, intake air is drawn into the supercharger 8 from the auxiliary intake passage 13 .

A discharge port of the supercharger 8 is provided with a valve 14 (switching mechanism). One end of the first passage 15 and one end of the second passage 16 are connected to the valve 14 . That is, the first passage 15 and the second passage 16 are connected to the supercharger 8 via the valve 14 . The other end of the first passage 15 is connected to the exhaust passage 5 upstream of the catalyst 7 and downstream of one end of the EGR passage 6 . The other end of the second passage 16 is connected to the intake manifold 3 .

The valve 14 is, for example, a three-way valve that opens and closes by electromagnetic control. The valve 14 can be switched between a first communication state, a second communication state, and a disconnection state. The first communication state is a state in which the discharge port of the supercharger 8 and the first passage 15 are communicated, and the discharge port of the supercharger 8 and the second passage 16 are disconnected. The second communication state is a state in which the discharge port of the supercharger 8 and the first passage 15 are disconnected and the discharge port of the supercharger 8 and the second passage 16 are communicated. That is, the valve 14 switches the discharge destination of the air compressed by the supercharger 8 between the first passage 15 and the second passage 16 . The disconnected state is a state in which the discharge port of the supercharger 8 and the first passage 15 are disconnected, and the discharge port of the supercharger 8 and the second passage 16 are disconnected.

FIG. 2 is a diagram for explaining the control system of the air supply system 1. As shown in FIG. As shown in FIG. 2, the air supply system 1 includes a temperature sensor Sa, a battery sensor Sb, a rotation speed sensor Sc, a torque sensor Sd, an ECU 20, an injector 17, a spark plug 18, a valve 14, a first clutch 11, a second clutch. 12, has a motor 9;

The temperature sensor Sa detects, for example, the temperature of the catalyst 7 or the vicinity of the catalyst 7 and outputs a signal indicating the detected temperature to the ECU 20 . The battery sensor Sb detects the remaining capacity (SOC: State Of Charge) of the battery 10 and outputs a signal indicating the detected remaining capacity to the ECU 20 . The rotation speed sensor Sc detects, for example, the rotation speed of the output shaft 2a as the engine rotation speed, and outputs a signal indicating the rotation speed to the ECU 20 . The torque sensor Sd detects, for example, the axial torque acting on the output shaft 2a and outputs a signal indicating the detected axial torque to the ECU 20 .

The ECU 20 is composed of a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing programs and the like, a RAM as a work area, and the like, and controls the engine 2 in an integrated manner. The ECU 20 also functions as a fuel control unit 21, an ignition control unit 22, a switching control unit 23, a clutch control unit 24, and a motor control unit 25 by executing programs.

The fuel control unit 21 controls the injector 17 of the engine 2 to inject fuel into the combustion chamber of the engine 2 . The fuel control unit 21 controls the fuel injection timing and injection amount of the injector 17 . The ignition control unit 22 controls the spark plug 18 of the engine 2 and causes the spark plug 18 to generate sparks within the combustion chamber. The ignition control unit 22 controls ignition timing of the spark plug 18 .

The switching control unit 23 controls the valve 14 based on the temperature of the catalyst 7 to bring the valve 14 into the first communication state or the second communication state. The clutch control unit 24 controls the first clutch 11 and the second clutch 12, and controls the supercharger 8 in the engine driving state, the motor driving state, and the state in which both the first clutch 11 and the second clutch 12 are disconnected. and The motor control unit 25 supplies electric power from the battery 10 to the motor 9 to drive the motor 9 in the motor driving state.

In the air supply system 1 , it is possible to transition to four modes of normal mode, mode 0 , mode 1 and mode 2 under the control of the switching control section 23 and the clutch control section 24 . Each mode will be described below.

FIG. 3 is a diagram for explaining the normal mode. As shown in FIG. 3 , in the normal mode, intake air taken into the supercharger 8 from the auxiliary intake passage 13 is compressed and discharged to the second passage 16 to flow into the intake manifold 3 .

When the temperature of the catalyst 7 is equal to or higher than the first temperature, the switching control unit 23 determines that warm-up of the catalyst 7 is unnecessary, and selects the normal mode. The switching control unit 23 controls the valve 14 to put it in the second communication state. As a result, intake air is supercharged into the cylinders of the engine 2, and output is increased and lean combustion is performed. The switching control unit 23 determines whether or not the temperature of the catalyst 7 is equal to or higher than the first temperature based on the signal from the temperature sensor Sa. The first temperature is, for example, a temperature that serves as a reference for determining whether the catalyst 7 needs to be warmed up.

Further, the clutch control unit 24 determines whether or not the remaining capacity of the battery 10 is equal to or less than the battery threshold value (predetermined threshold value) based on the signal from the battery sensor Sb. The battery threshold is a threshold that serves as a criterion for determining whether the battery 10 can be used. If the remaining capacity of the battery 10 is equal to or less than the battery threshold, the clutch control unit 24 selects the engine drive state, connects the first clutch 11 and disconnects the second clutch 12 . This avoids a situation in which the battery 10 is exhausted when the remaining capacity of the battery 10 is low.

When the remaining capacity of the battery 10 is greater than the battery threshold value, the clutch control unit 24 selects one of the engine driving state and the motor driving state based on the thermal efficiency of the engine 2 . The thermal efficiency of the engine 2 is preset as an efficiency map of engine speed and shaft torque. The clutch control unit 24 derives the thermal efficiency of the engine 2 by referring to the efficiency map based on the signal from the rotation speed sensor Sc and the signal from the torque sensor Sd. Then, the clutch control unit 24 determines whether or not the derived thermal efficiency is equal to or less than the efficiency threshold.

If the thermal efficiency of the engine 2 is equal to or less than the efficiency threshold, the clutch control unit 24 selects the motor drive state, disconnects the first clutch 11 and connects the second clutch 12 . If the thermal efficiency of the engine 2 is greater than the efficiency threshold, the clutch control unit 24 selects the engine drive state, connects the first clutch 11 and disconnects the second clutch 12 . As a result, the motor 9 can be used under operating conditions in which the thermal efficiency of the engine 2 is low, and the engine 2 can be used when the thermal efficiency of the engine 2 is high.

FIG. 4 is a diagram for explaining mode 0. FIG. As shown in FIG. 4, in mode 0, both the first clutch 11 and the second clutch 12 are disconnected. Therefore, supercharger 8 is not driven. Also, the switching control unit 23 turns off the valve 14 . For example, the fuel control unit 21 increases the amount of fuel injected by the injector 17 compared to when the catalyst 7 is not warmed up. The ignition control unit 22 retards the ignition timing of the spark plug 18 from when the catalyst 7 is not warmed up (retard control). In the retard control, for example, the maximum retardation occurs during idling, and the retardation amount decreases according to the required torque of the engine 2 .

In mode 0, when the energy required for driving the supercharger 8 is greater than the energy required for warming up the catalyst 7, the catalyst 7 can be efficiently warmed up by stopping the driving of the supercharger 8. can.

When the temperature of the catalyst 7 is less than the first temperature and equal to or higher than the second temperature, the clutch control unit 24 disengages the first clutch 11 and the second clutch 12 to set mode 0. The second temperature is a value lower than the first temperature.

Mode 0 is selected when the supercharger 8 cannot operate even if the temperature of the catalyst 7 is lower than the second temperature. Examples of the case where the supercharger 8 cannot operate include a failure of the supercharger 8, a case where the outside air temperature is too low (adhesion of lubricating oil), and the like.

FIG. 5 is a diagram for explaining mode 1. FIG. As shown in FIG. 5 , in mode 1 , the intake air taken into the supercharger 8 from the auxiliary intake passage 13 is compressed, discharged to the first passage 15 , and flows into the exhaust passage 5 . The fuel control unit 21 increases the amount of fuel injected by the injector 17 compared to when the catalyst 7 is not warmed up. The ignition control unit 22 retards the ignition timing of the spark plug 18 from when the catalyst 7 is not warmed up.

When the temperature of the catalyst 7 is lower than the second temperature and the supercharger 8 can operate, the switching control unit 23 controls the valve 14 to bring it into the first communication state. When the temperature of the catalyst 7 is lower than the second temperature and the supercharger 8 can operate, the clutch control unit 24 determines whether the remaining capacity of the battery 10 is sufficient based on the signal from the battery sensor Sb. do. That the remaining capacity of the battery 10 is sufficient means that the remaining capacity of the battery 10 is greater than the battery threshold (threshold).

If the remaining capacity of the battery 10 is not sufficient, the clutch control unit 24 connects the first clutch 11 and disconnects the second clutch 12 to bring the engine into the driving state. Thus, the air supply system 1 is in mode 1.

FIG. 6 is a diagram for explaining mode 2. FIG. In mode 1, the engine is driven, while in mode 2, the motor is driven, as shown in FIG. When the temperature of the catalyst 7 is lower than the second temperature and the supercharger 8 can operate, the clutch control unit 24 determines whether the remaining capacity of the battery 10 is sufficient based on the signal from the battery sensor Sb. do. If the remaining capacity of the battery 10 is sufficient, the clutch control unit 24 disconnects the first clutch 11 and connects the second clutch 12 to set the motor driving state. Thus, the air supply system 1 is in mode 2.

Since compressed air is supplied to the catalyst 7 in modes 1 and 2, more fuel can be burned in the vicinity of the catalyst 7 . Therefore, the warm-up of the catalyst 7 is quickly completed, and retard control is prevented from prolonging, thereby suppressing deterioration of fuel consumption. Furthermore, in mode 2, the drive load of the engine 2 is reduced by disengaging the first clutch 11, so the combustion energy of the engine 2 can be efficiently used to warm up the catalyst 7.

FIG. 7 is a flow chart showing the flow of air supply processing. The processing shown in FIG. 7 is repeatedly executed at a predetermined cycle. As shown in FIG. 7, the clutch control unit 24 determines whether the temperature of the catalyst 7 is equal to or higher than the first temperature (S100). When the temperature of the catalyst 7 is equal to or higher than the first temperature (YES in S100), the clutch control section 24 brings the valve 14 into the second communication state. The normal mode in which the discharge destination of the supercharger 8 is the second passage 16 is entered (S102), and the air supply process ends. Note that the clutch control unit 24 selects the engine driving state or the motor driving state based on the remaining capacity of the battery 10 and the thermal efficiency of the engine 2 .

When the temperature of the catalyst 7 is less than the first temperature (NO in S100), the clutch control unit 24 determines whether the temperature of the catalyst 7 is equal to or higher than the second temperature (S104). When the temperature of the catalyst 7 is equal to or higher than the second temperature (YES in S104), the clutch control unit 24 sets mode 0 in which both the first clutch 11 and the second clutch 12 are disconnected (S108), and performs the air supply process. ends. Also, the switching control unit 23 turns off the valve 14 .

Instead of disengaging the second clutch 12, the motor control unit 25 may cut off the power supply from the battery 10 to the motor 9 to stop driving the motor 9, thereby stopping the operation of the supercharger 8. .

If the temperature of catalyst 7 is lower than the second temperature (NO in S104), clutch control unit 24 determines whether supercharger 8 is operable (S106). If the supercharger 8 is not operable (NO in S106), the process proceeds to S108, mode 0 is selected, and the air supply process ends.

If supercharger 8 is operable (YES in S106), clutch control unit 24 determines whether the remaining capacity of battery 10 is sufficient (S110). When the remaining capacity of the battery 10 is not sufficient (NO in S110), the clutch control unit 24 connects the first clutch 11 and disconnects the second clutch 12 to set the engine in the driving state (S112). After that, the process moves to S116, and mode 1 is entered.

When the remaining capacity of the battery 10 is sufficient (YES in S110), the clutch control unit 24 disconnects the first clutch 11 and connects the second clutch 12 to set the battery drive state (S114). After that, the process moves to S116, and mode 2 is entered.

The switching control unit 23 puts the valve 14 in the first communication state (S116). The intake air taken into the supercharger 8 from the auxiliary intake passage 13 is compressed. The compressed air is discharged into the first passage 15 and flows into the exhaust passage 5 . Thus, the air supply process ends.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope of the claims, and it should be understood that these also belong to the technical scope of the present invention. be done.

For example, in the embodiment described above, the case where the temperature sensor Sa is provided has been described. However, the temperature sensor Sa is not an essential component. The temperature of the catalyst 7 may be estimated from the outside air temperature and the operating conditions of the engine 2 without providing the temperature sensor Sa. Further, in the exhaust passage 5, air-fuel ratio (A/F) sensors provided upstream and downstream of the catalyst 7 warm up the catalyst 7 by calculating backward from the purification action of the catalyst 7. You can decide whether

Further, in the above-described embodiment, the valve 14 has been described as being switchable between the first communication state and the second communication state. However, valve 14 may, for example, distribute compressed air discharged from supercharger 8 to both first passage 15 and second passage 16 . Valve 14 may be adjustable in its distribution ratio.

Further, in the embodiment described above, the case where the first clutch 11 and the second clutch 12 are controlled based on both the remaining capacity of the battery 10 and the thermal efficiency of the engine 2 has been described. However, the first clutch 11 and the second clutch 12 may be controlled based on at least one of the remaining capacity of the battery 10 and the thermal efficiency of the engine 2 .

Also, in the above-described embodiment, the case where mode 0 is provided has been described. However, mode 0 is not essential control. However, when mode 0 is provided, even though a large amount of heat is not required for warm-up, compressed air is supplied to the catalyst 7 to avoid a situation in which a large amount of fuel is increased and fuel is wasted. It becomes possible to

Also, the amount of compressed air discharged by the supercharger 8 may be variably controlled. For example, the supercharger 8 may have its rotation speed controlled by the first clutch 11, the second clutch 12, the motor 9, etc., or the supercharger 8 itself may be provided with a mechanism for varying the discharge amount. . As a result, the amount of compressed air supplied to the catalyst 7 is optimized, and the warm-up of the catalyst 7 is accelerated. Specifically, a warm-up map is provided in which the amount of air is set with respect to the outside temperature. The amount of air to be supplied is specified from the outside air temperature and warm-up map, and the fuel injection amount is increased corresponding to the amount of air.

INDUSTRIAL APPLICABILITY The present invention can be used in air supply systems.

1 air supply system 2 engine 2a output shaft 4 intake passage 5 exhaust passage 7 catalyst 8 supercharger 9 motor 9a output shaft 10 battery 11 first clutch 12 second clutch 14 valve (switching mechanism)
15 First passage 16 Second passage 23 Switch control unit 24 Clutch control unit

Claims (4)

a supercharger connected to the output shaft of the engine via a first clutch and connected to the output shaft of the motor via a second clutch;
a first passage that is connected to the supercharger and communicates upstream of a catalyst that purifies exhaust gas in the exhaust passage of the engine;
a second passage connected to the supercharger and communicating with an intake passage of the engine;
a switching mechanism for switching a discharge destination of the air compressed by the supercharger between the first passage and the second passage;
When the temperature of the catalyst is equal to or higher than the first temperature, the switching mechanism is controlled so that the discharge destination is the second passage, and when the temperature of the catalyst is lower than the second temperature lower than the first temperature, a switching control unit that controls the switching mechanism so that the discharge destination is the first passage;
a clutch control unit that disconnects the first clutch and the second clutch to stop driving the supercharger when the temperature of the catalyst is lower than the first temperature but higher than or equal to the second temperature;
air supply system with a fuel control unit that increases the amount of fuel injected in the engine when the temperature of the catalyst is less than the first temperature and is equal to or higher than the second temperature, compared to when the temperature of the catalyst is equal to or higher than the first temperature; and at least an ignition control section for retarding the ignition timing of the engine when the temperature of the catalyst is less than the first temperature and equal to or higher than the second temperature compared to when the temperature of the catalyst is equal to or higher than the first temperature 2. The air supply system of claim 1, further comprising one. 3. The clutch control unit according to claim 1 , wherein the clutch control unit controls the first clutch and the second clutch based on at least one of remaining capacity of a battery that supplies electric power to the motor and thermal efficiency of the engine. air supply system. The clutch control unit engages the first clutch and disconnects the second clutch when the remaining capacity of the battery is equal to or less than a predetermined threshold, and disconnects the second clutch when the remaining capacity of the battery is greater than the predetermined threshold. 4. The air supply system according to claim 3 , wherein said first clutch and said second clutch are engaged or disengaged based on thermal efficiency of said engine.

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