JP2009162188A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of effectively and compatibly materializing acceleration of warming up of a catalyst and elimination of shortage of braking force of a vehicle. <P>SOLUTION: When catalyst warming-up demand exists in this device, ignition timing θ is set at a greatly retarded side θ0+θA from normal timing θ0 at first, and throttle valve opening TA is set at greater opening TA0+TAA than normal opening TA0 (first catalyst warming up control setting a main purpose on catalyst warming up). When a vehicle is started under this condition, θ is set at timing θ0+θA-θB between θ0+θA and θ0 and TA is set to opening TA0+TAB between TA0+TAA and TA0 (second catalyst warming up control) after θ is set at same timing as θ0 and TA is set at same opening as TA0 (negative pressure increase control setting main purpose on negative pressure increase) for time T1 (very short time). In addition to that, operation of an air-conditioner is prohibited during negative pressure increase control, and is allowed during the second warming up control. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine that performs control for retarding an ignition timing in order to promote warm-up of a catalyst disposed in an exhaust passage of the internal combustion engine.

  Conventionally, when the internal combustion engine is started (particularly during cold start), the exhaust gas purifying catalyst disposed in the exhaust passage is promoted to be warmed up so that the state of the catalyst can be quickly activated (early). In order to sufficiently purify the exhaust gas), the timing to generate sparks in the combustion chamber (ignition timing) is retarded from the normal ignition timing (normal ignition timing) (ignition timing delay control) ) To increase the temperature of the exhaust gas is known.

  When this ignition timing retardation control is performed, the torque (output torque) output from the internal combustion engine is reduced. In the above control device, in general, the throttle valve opening (throttle valve opening) is controlled to be larger than the normal throttle valve opening (normal throttle valve opening) in conjunction with the ignition timing retardation control (throttle valve opening). Degree increase control) is performed. When the throttle valve opening increase control is performed, the amount of air taken into the combustion chamber (cylinder air amount) and the amount of fuel supplied into the combustion chamber increase in proportion to the amount of air. As a result, the combustion energy in the combustion chamber increases, so that the above-described decrease in output torque due to ignition timing retardation control can be compensated. Hereinafter, the ignition timing retardation control and the throttle valve opening increase control are collectively referred to as “catalyst warm-up control”.

  When this throttle valve opening increase control is performed, the air pressure (throttle valve downstream pressure) lower than the atmospheric pressure downstream of the throttle valve in the intake passage rises and approaches the atmospheric pressure. Therefore, a braking booster (brake) that increases the braking force of the vehicle by increasing the brake operating force by utilizing the pressure difference between the downstream pressure of the throttle valve (actually, the negative pressure chamber pressure described later) and the atmospheric pressure. In a vehicle equipped with a booster), during the catalyst warm-up control, the brake pressure of the vehicle may be insufficient because the differential pressure decreases and the brake booster cannot sufficiently increase the brake operation force. In the present specification, a pressure lower than the atmospheric pressure may be referred to as “negative pressure”. In this case, “increasing (decreasing) negative pressure” means “decreasing (increasing) pressure”.

Therefore, one of the other control devices has a relatively sufficient braking force after the start of the vehicle even when the catalyst warm-up control is to be performed, such as during cold start. When required (when there is a request to increase negative pressure), the catalyst warm-up control is stopped, the throttle valve opening is returned to the normal throttle valve opening, and the ignition timing is returned to the normal ignition timing (negative Pressure increase control) (see, for example, Patent Document 1). As a result, the downstream pressure of the throttle valve decreases again (that is, the differential pressure increases), and the above shortage of braking force can be resolved.
JP 2002-327639 A

  As described above, a case is considered in which the catalyst warm-up control is stopped and the negative pressure increase control is performed due to the start of the vehicle (therefore, a negative pressure increase request). Normally, from the start of the negative pressure increase control until the pressure inside the negative pressure chamber (negative pressure chamber pressure) that stores the negative pressure disposed in the brake booster decreases to such a degree that the braking force can be increased sufficiently. The time required is relatively short (for example, about 1 to 2 seconds). In other words, the intended purpose of the negative pressure increase control for eliminating the shortage of braking force can be achieved by executing this negative pressure increase control for a relatively short time.

  Furthermore, if the negative pressure increase control execution period is long, the catalyst warm-up control stop period becomes long. In this case, since the warm-up of the catalyst cannot be promoted, the period during which the exhaust gas cannot be sufficiently purified by the catalyst becomes longer. From the above, it is considered that the negative pressure increase control is preferably stopped after being executed for a relatively short time.

  In this case, in order to promote warming up of the catalyst, it is conceivable that the same control as the catalyst warming up control described above is executed again after the negative pressure increase control is stopped. This means that the throttle valve downstream pressure rises again to the same extent. Here, in the brake booster, the negative pressure chamber pressure can be increased every time the braking force increasing action is exerted (because negative pressure can be consumed). Therefore, the throttle valve downstream pressure is increased every time the braking force increasing action is exerted. It is necessary to repeatedly reduce the negative pressure chamber pressure (supplement negative pressure) by using.

  However, if the throttle valve downstream pressure is sufficiently increased to the same extent by re-execution of the same control as the catalyst warm-up control described above, the negative pressure cannot be sufficiently supplemented. Therefore, in the case where the brake operation is performed relatively frequently during traveling of the vehicle after the negative pressure increase control is stopped, the braking force shortage may occur again due to the above-described decrease in the differential pressure. There is.

  The present invention has been made to address the above-described problems, and an object of the present invention is an internal combustion engine capable of effectively achieving both promotion of warm-up of the catalyst and elimination of deficiency of the braking force of the vehicle. It is to provide an engine control device.

  In order to achieve the above object, an internal combustion engine control apparatus according to the present invention comprises a throttle valve driving means for driving a throttle valve disposed in an intake passage of an internal combustion engine mounted on a vehicle in response to a predetermined drive instruction signal. A braking boost that increases the braking force of the vehicle by increasing the brake operating force by utilizing the throttle valve downstream pressure that is lower than the atmospheric pressure generated downstream of the throttle valve in the intake passage. Means, ignition means for igniting the air-fuel mixture supplied to the combustion chamber of the internal combustion engine in response to a predetermined ignition instruction signal, and an exhaust gas purifying catalyst disposed in the exhaust passage of the internal combustion engine.

  Further, the control device includes a warm-up request determination unit that determines whether or not there is a catalyst warm-up request for promoting warm-up of the catalyst, and the throttle valve downstream pressure when it is determined that the catalyst warm-up request exists. Increase request determination means for determining whether or not there is a negative pressure increase request for decreasing the pressure. Here, the catalyst warm-up request is determined as “present” when, for example, the temperature of the catalyst is lower than a predetermined value. The negative pressure increase request is determined to be “present” when it is determined that the vehicle has started, for example.

  The control device further includes normal control means, first catalyst warm-up control means, and negative pressure increase control means. When it is determined that there is no catalyst warm-up request (for example, after the catalyst warm-up is completed, etc.), the normal control means transmits the ignition instruction signal to the ignition means, thereby The ignition timing is controlled to a normal ignition timing that is determined based on the operating state of the internal combustion engine, and the opening degree of the throttle valve is controlled by transmitting the drive instruction signal to the throttle valve driving means. Control is made to a normal throttle valve opening which is an opening determined based on the operating state of the internal combustion engine.

  The first catalyst warm-up control means determines that there is a request for warming up the catalyst and that there is no request for increasing the negative pressure (for example, when the vehicle is stopped after a cold start), By transmitting the ignition instruction signal to the ignition means, the ignition timing is controlled to a first ignition timing that is retarded from the normal ignition timing, and the drive to the throttle valve driving means is performed. By transmitting the instruction signal, the opening degree of the throttle valve is controlled to the first throttle valve opening degree that is larger than the normal throttle valve opening degree. By the first catalyst warm-up control, as described above, the temperature of the catalyst can be quickly brought close to the activation temperature while compensating for the decrease in the output torque of the internal combustion engine.

  The negative pressure increase control means determines that there is a negative pressure increase request during the execution of control by the first catalyst warm-up control means (that is, there is a catalyst warm-up request) (for example, cold start) (For example, when the vehicle starts later) (the control by the first catalyst warm-up control unit is stopped), and the ignition instruction signal is transmitted to the ignition unit to thereby set the ignition timing to the first ignition The throttle valve opening is controlled to the second ignition timing, which is a timing advanced from the timing, and the drive instruction signal is transmitted to the throttle valve driving means, thereby adjusting the throttle valve opening to the first throttle valve opening. The second throttle valve opening is controlled to a smaller opening.

  Here, the second ignition timing is a timing equal to the normal ignition timing or a timing retarded from the normal ignition timing. The second throttle valve opening is an opening equal to the normal throttle valve opening or an opening larger than the normal throttle valve opening. Due to the start of the negative pressure increase control, as described above, after a relatively short time (for example, about 1 to 2 seconds), the braking force is insufficient due to the decrease in the differential pressure in the braking booster. Can be resolved. That is, it is possible to exert a sufficient braking force immediately after the vehicle starts.

  This control device is characterized in that it includes second catalyst warm-up control means. When the second catalyst warm-up control means determines that a predetermined condition is satisfied during the execution of the control by the negative pressure increase control means (for example, when there is a catalyst warm-up request) (for example, start of negative pressure increase control) 1 to 2 seconds have elapsed), the control by the negative pressure increase control means is stopped (and the negative pressure increase request is set to “None”), and the throttle valve downstream pressure is set to open the throttle valve. Within a range that is higher than the pressure corresponding to when the second throttle valve opening is maintained and lower than the corresponding pressure when the throttle valve opening is maintained at the first throttle valve opening. The ignition timing is transmitted between the first ignition timing and the second ignition timing by transmitting the ignition instruction signal to the ignition means so that the pressure is maintained below a predetermined pressure. Control to the third ignition timing At the same time, by transmitting the drive instruction signal to the throttle valve driving means, the opening of the throttle valve is an opening between the first throttle valve opening and the second throttle valve opening. Control to 3 throttle valve opening.

  Here, as the predetermined condition, for example, the pressure inside the negative pressure chamber (negative pressure chamber pressure) that stores air having a pressure lower than the atmospheric pressure of the braking boost means from the start of the negative pressure increase control. It may be adopted that the time required until the braking force is reduced to such an extent that the braking force can be appropriately increased has elapsed.

  When the negative pressure increase control is stopped and the second catalyst warm-up control is started / executed in this way, the ignition timing is set to the retard side compared to during the negative pressure increase control. Therefore, compared with the case where the negative pressure increase control is continued, the catalyst warm-up can be promoted and the catalyst temperature can be brought close to the activation temperature quickly. In addition, the throttle valve opening is set to a smaller opening than during the first catalyst warm-up control. Therefore, the throttle valve downstream pressure can be maintained at a lower pressure (the predetermined pressure or less) compared to the case where the first catalyst warm-up control is started and executed after the negative pressure increase control is stopped. In other words, even if the brake operation is performed relatively frequently while the vehicle is running after the negative pressure increase control is stopped, the above-described “replenishment of negative pressure” can be sufficiently performed, and the above-described insufficient braking force can be generated. Can be suppressed.

  As described above, the negative pressure increase control is stopped as described above, and the second catalyst warm-up control is started and executed, thereby effectively achieving both promotion of catalyst warm-up and elimination of insufficient braking force of the vehicle. It becomes possible.

  In the control device according to the present invention, in the case where the load device is mounted on the vehicle and driven by the power of the internal combustion engine, the load device is driven by the internal combustion engine during the execution of the control by the negative pressure increase control means. It is preferable that the driving is prohibited and the driving by the internal combustion engine is permitted during the execution of the control by the second catalyst warm-up control means. Here, the load device is, for example, a vehicle air conditioner (air conditioner).

  While the air conditioner (more specifically, its compressor) is being driven, a part of the power of the internal combustion engine is consumed for driving the air conditioner, so the power of the internal combustion engine that can be used for driving the vehicle is reduced. Decrease. Therefore, normally, while the air conditioner is being driven, the throttle valve opening is increased (that is, the combustion energy is increased) as compared with the case where the air conditioner is not being driven, so that the reduction in power is compensated. In other words, when the air conditioner is not driven, the throttle valve downstream pressure becomes lower than when the air conditioner is driven, and the above-described “replenishment of negative pressure” can be performed more quickly. In addition, even if the driving of the air conditioner is interrupted for a relatively short time (for example, about 1 to 2 seconds), the air conditioning control in the passenger compartment is hardly adversely affected.

  The above configuration is based on such knowledge. Thereby, during the negative pressure increase control, the throttle valve downstream pressure is reduced as much as possible by prohibiting the driving of the air conditioner, and the above-described “replenishment of negative pressure” can be achieved more reliably. In addition, since the drive prohibition period of the air conditioner is limited to a relatively short time during which the negative pressure increase control is executed, the air conditioning control can be favorably maintained without adversely affecting the air conditioning control.

  In the control device according to the present invention, the second catalyst comprises operating speed acquisition means for acquiring an operating speed of the internal combustion engine, and cooling water temperature acquisition means for acquiring a temperature of cooling water for cooling the internal combustion engine. Preferably, the warm-up control means is configured to determine the third ignition timing (and the third throttle valve opening) based on one or both of the operation speed and the coolant temperature. It is. Here, for example, the higher the operating speed or the higher the coolant temperature, the more the third ignition timing is set to the retard side, and the third throttle valve opening is set to a larger opening. .

  Generally, as the operating speed of the internal combustion engine increases (under a constant throttle valve opening), the throttle valve downstream pressure becomes lower. This means that even if the ignition timing is set to be retarded as the operating speed increases (thus, even if the throttle valve opening is set to a larger value), the downstream pressure of the throttle valve is “replenished with negative pressure”. "Can be maintained at a sufficiently low pressure (= the predetermined pressure or less) necessary to be able to be reliably achieved.

  Further, when the cooling water temperature is low, the frictional resistance against the movement of each movable member in the internal combustion engine is increased. Accordingly, the amount consumed by the frictional resistance in the power of the internal combustion engine increases, and the power of the internal combustion engine that can be used for driving the vehicle decreases. Therefore, normally, when the coolant temperature is low, the throttle valve opening is increased (that is, the combustion energy is increased) to compensate for the reduction in power. In other words, as the coolant temperature becomes higher, the throttle valve opening is made smaller and the throttle valve downstream pressure becomes lower. This means that even if the ignition timing is set to a more retarded side as the coolant temperature increases (thus, even if the throttle valve opening is set to a larger value), the throttle valve downstream pressure is set to “replenish negative pressure”. "Can be maintained at a sufficiently low pressure (= the predetermined pressure or less) necessary to be able to be reliably achieved.

  The above configuration is based on such knowledge. According to this, for example, during the second catalyst warm-up control, the ignition timing is set to a more retarded side and the throttle valve opening is set to a larger opening as the operating speed is higher or the coolant temperature is higher. Is set. As a result, while maintaining the throttle valve downstream pressure at a sufficiently low pressure (= the predetermined pressure or less), the ignition timing can be set to the retard side as much as possible to bring the temperature of the catalyst closer to the activation temperature as soon as possible.

  The control device according to the present invention further includes pressure acquisition means for acquiring the throttle valve downstream pressure, and the second catalyst warm-up control means is configured such that the acquired throttle valve downstream pressure is within the range. The third ignition timing (and the third throttle valve opening) is feedback-controlled based on the acquired throttle valve downstream pressure so as to match the reference pressure equal to or lower than the predetermined pressure. Good.

  More specifically, when the acquired throttle valve downstream pressure is higher than the reference pressure, the third ignition timing is adjusted to an advance side from the current ignition timing, and the third throttle valve opening degree Is adjusted to an opening smaller than the current opening. On the other hand, when the acquired throttle valve downstream pressure is lower than the reference pressure, the third ignition timing is adjusted to be retarded from the current ignition timing, and the third throttle valve opening is the current opening. The degree of opening is adjusted to a degree greater than

  According to this, the throttle valve downstream pressure can be directly and reliably adjusted to a sufficiently low pressure (= the predetermined pressure or less) during the second catalyst warm-up control. Therefore, even if the brake operation is performed relatively frequently during the traveling of the vehicle under the second catalyst warm-up control, the above-described “replenishment of negative pressure” can be reliably performed, and the occurrence of the above-described insufficient braking force can be ensured. Can be suppressed.

  In the control device according to the present invention, the second catalyst warm-up control means determines the third ignition timing so that the third ignition timing is not advanced from the normal ignition timing. It is preferable that the third throttle valve opening is determined so that the third throttle valve opening does not become smaller than the normal throttle valve opening. According to this, during the second catalyst warm-up control, it is possible to avoid a situation in which the ignition timing is more advanced than the normal ignition timing and the catalyst warm-up cannot be promoted.

  The control apparatus according to the present invention further includes an idling determination unit that determines whether or not the internal combustion engine is idling. The second catalyst warm-up control unit includes the second catalyst warm-up control unit. When the internal combustion engine is not in an idling state during the execution of the control by the control, the third ignition timing is a timing equal to the first ignition timing or a timing advanced from the first ignition timing, and the internal combustion engine Is set to a timing retarded from the third ignition timing when the engine is in an idling state (and the third throttle valve opening is equal to the first throttle valve opening, or So that the opening is smaller than the first throttle valve opening and larger than the third throttle valve opening when the internal combustion engine is idling) It is preferable to be made. Here, the idling state corresponds to a state where the operation amount of the acceleration operation member (accelerator pedal or the like) operated by the driver is “0” or a state close to “0”.

  While the driver is operating the acceleration operating member (that is, when not in an idling state), the possibility that the brake operation is performed is very low. Therefore, when the idling state is not established during the second catalyst warm-up control, it can be considered that priority is given to promoting the warm-up of the catalyst over the elimination of the lack of the braking force of the vehicle. The above configuration is based on such knowledge. According to this, when the idling state is not established during the second catalyst warm-up control, the ignition timing is set to the retard side as much as possible, so that the temperature of the catalyst can be brought close to the activation temperature as early as possible.

  Further, when it is determined that the negative pressure increase request is made when it is determined that the vehicle has started as described above, the control device according to the present invention stops the vehicle. Stop determination means for determining whether or not the vehicle is stopped when the first catalyst warm-up control means is performing control by the second catalyst warm-up control means. It is preferable that the warm-up control is stopped, the ignition timing is controlled to the first ignition timing, and the throttle valve opening is controlled to the first throttle valve opening.

  When the vehicle stops during the second catalyst warm-up control, it is less necessary to adjust the throttle valve downstream pressure to a sufficiently low pressure (= the predetermined pressure or less) after that. Therefore, it is preferable to prioritize the promotion of warm-up of the catalyst over the elimination of the lack of braking force of the vehicle. The above configuration is based on such knowledge. According to this, when the vehicle stops during the second catalyst warm-up control, the first catalyst warm-up control is executed again and the ignition timing is set to the retard side as much as possible. As a result, the temperature of the catalyst can be brought close to the activation temperature as early as possible.

<Configuration>
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a system in which an internal combustion engine control apparatus according to an embodiment of the present invention is applied to a multi-cylinder (four-cylinder) internal combustion engine 10 operated by a four-cycle spark ignition system. FIG. 1 shows only a cross section of a specific cylinder, but the other cylinders have the same configuration.

  The internal combustion engine 10 is mounted on a vehicle. The internal combustion engine 10 is mixed with a cylinder block 20 including a cylinder block, a cylinder block lower case (not shown) and an oil pan (not shown), a cylinder head 30 fixed on the cylinder block 20, and the cylinder block 20. An intake system 40 for supplying air (gasoline mixture in this example) and an exhaust system 50 for discharging exhaust gas from the cylinder block unit 20 to the outside are included.

  The cylinder block unit 20 includes a cylinder 21, a piston 22, a connecting rod 23, and a crankshaft 24. The piston 22 reciprocates in the cylinder 21, and the reciprocating motion of the piston 22 is transmitted to the crankshaft 24 via the connecting rod 23, whereby the crankshaft 24 rotates. The cylinder 21, the head of the piston 22, and the cylinder head portion 30 form a combustion chamber (cylinder) 25.

  The cylinder head portion 30 includes an intake port 31 that communicates with the combustion chamber 25, an intake valve 32 that opens and closes the intake port 31, an intake cam shaft that drives the intake valve 32, and continuously changes the phase angle of the intake cam shaft. A variable intake timing device 33, an actuator 33a of the variable intake timing device 33, an exhaust port 34 communicating with the combustion chamber 25, an exhaust valve 35 that opens and closes the exhaust port 34, an exhaust cam shaft that drives the exhaust valve 35, and an exhaust cam shaft The variable exhaust timing device 36 that continuously changes the phase angle of the engine, the actuator 36a of the variable exhaust timing device 36, the ignition plug 37, an igniter 38 that includes an ignition coil that generates a high voltage to be applied to the ignition plug 37, and fuel to the intake port 31. Inject And a injector (fuel injection means) 39 for supplying the fuel into the combustion chamber 25 by the.

  The spark plug 37 is disposed so as to ignite the air-fuel mixture supplied to the combustion chamber 25 by generating a spark. The igniter 38 generates a spark by the spark plug 37 in response to an ignition instruction signal transmitted from an electric control device 80 described later. The spark plug 37 and the igniter 38 constitute an ignition means.

  The intake system 40 includes an intake manifold 41 including a plurality of independent passages that communicate with the intake ports 31 of the cylinders, a surge tank 42 that communicates with all the passages of the intake manifold 41, and an intake air that has one end connected to the surge tank 42. A duct 43, an air filter 44, a throttle valve 45, and a throttle valve actuator 45a as a throttle valve driving means are provided in the intake duct 43 in order from the other end of the intake duct 43 to the downstream (surge tank 42). Yes. The intake port 31, the intake manifold 41, the surge tank 42, and the intake duct 43 form an intake passage through which air taken from the outside of the internal combustion engine 10 is introduced into the cylinder.

  The throttle valve actuator 45a is a DC motor. The throttle valve actuator 45a drives the throttle valve 45 in response to a drive instruction signal transmitted from an electric control device 80 described later. The throttle valve 45 and the throttle valve actuator 45a constitute throttle valve driving means.

  The exhaust system 50 includes an exhaust manifold 51 composed of a plurality of independent passages communicating with the exhaust ports 34 of the respective cylinders, and a collecting portion for collecting these passages downstream, and an exhaust pipe connected to the collecting portion of the exhaust manifold 51. (Exhaust pipe) 52, three-way catalyst 53 disposed (intervened) in the exhaust pipe 52 (also referred to as "upstream side catalytic converter or start catalytic converter", hereinafter referred to as "first catalyst 53") And the downstream three-way catalyst 54 (disposed below the vehicle floor, which is disposed (intervened) in the exhaust pipe 52 downstream of the first catalyst 53, which is also called an under-floor catalytic converter. Hereinafter referred to as “second catalyst 54”). The exhaust port 34, the exhaust manifold 51, and the exhaust pipe 52 form an exhaust passage through which exhaust gas, which is a combustion gas generated by combustion of an air-fuel mixture containing fuel and air, in the combustion chamber 25 passes. Yes.

  Each of the first catalyst 53 and the second catalyst 54 occludes oxygen in the exhaust gas. Further, each of the first catalyst 53 and the second catalyst 54 promotes the reaction between the unburned components of the fuel in the exhaust gas and the oxygen in the exhaust gas or the stored oxygen to remove harmful substances in the exhaust gas. It purifies (purifies exhaust gas). The first catalyst 53 and the second catalyst 54 constitute an exhaust purification catalyst.

  Further, the internal combustion engine 10 includes a negative pressure accumulator 60. The negative pressure accumulating unit 60 includes a bypass passage 61, a bypass flow rate control valve 62, a negative pressure introduction main passage 63, a negative pressure introduction sub passage 64, and a brake booster 65 as a brake booster. ing.

  One end of the bypass passage 61 is connected to the intake duct 43 upstream of the throttle valve 45, and the other end is connected to the surge tank 42. The bypass passage 61 has a constant passage cross-sectional area and an upstream portion 61a including the upstream end portion of the bypass passage 61, the same passage cross-sectional area as the upstream portion 61a, and a constant passage cross-sectional area; A downstream portion 61b including a downstream end portion of the bypass passage 61, and a central portion located between the upstream portion 61a and the downstream portion 61b and having a passage sectional area smaller than the passage sectional areas of the upstream portion 61a and the downstream portion 61b 61c.

The central portion 61c is formed with a throttle portion 61c1 that is a portion of the bypass passage 61 having a minimum passage cross-sectional area. A portion of the central portion 61c adjacent to the throttle portion 61c1 has a gradually increasing cross-sectional area as the distance from the throttle portion 61c1 increases in the length direction of the central portion 61c.
With such a configuration, the pressure of the air in the bypass passage 61 when the air passes through the bypass passage 61 is lowest in the throttle portion 61c1.

  The bypass flow control valve 62 is disposed in the upstream portion 61 a of the bypass passage 61. The bypass flow rate control valve 62 is configured to switch the bypass passage 61 between a communication state and a cutoff state by driving a valve body (not shown) in response to the opening / closing instruction signal.

  One end of the negative pressure introducing main passage 63 is connected to the downstream portion 61 b of the bypass passage 61, and the other end is connected to the brake booster 65. At both ends of the main passage 63 for introducing negative pressure, check valves are provided that allow air to flow from the brake booster 65 toward the bypass passage 61 and prevent air from flowing in the opposite direction. Has been.

  One end of the negative pressure introducing sub-passage 64 is connected to the throttle portion 61 c 1, and the other end is connected to the central portion of the negative pressure introducing main passage 63. A check valve that allows air to flow from the negative pressure introducing main passage 63 toward the throttle portion 61c1 in the central portion of the negative pressure introducing sub passage 64 and prevents air from flowing in the opposite direction. Is arranged.

  The brake booster 65 is an integrated vacuum type brake booster. The brake booster 65 has two negative pressure chambers (not shown) formed therein. The brake booster 65 discharges air in the negative pressure chamber to the bypass passage 61 through the negative pressure introduction main passage 63 and the negative pressure introduction sub passage 64, thereby having a pressure (negative pressure) lower than the atmospheric pressure. Is stored in the negative pressure chamber.

  With such a configuration, when the pressure of air in the surge tank 42 (throttle valve downstream pressure) decreases, the pressure in the negative pressure chamber (negative pressure chamber pressure) of the brake booster 65 becomes almost the same as the throttle valve downstream pressure without delay. Match. Furthermore, the negative pressure chamber pressure of the brake booster 65 approaches the air pressure of the throttle portion 61c1 that is lower than the throttle valve downstream pressure relatively slowly. That is, the negative pressure chamber pressure of the brake booster 65 is always maintained at a pressure equal to or lower than the pressure of the air in the surge tank 42 (that is, the throttle valve downstream pressure).

  Furthermore, the brake booster 65 introduces air into one negative pressure chamber when the brake pedal BP is depressed. The brake booster 65 uses a differential pressure between the atmospheric pressure in one negative pressure chamber and the pressure of the air in the other negative pressure chamber (negative pressure), so that the brake pedal BP is depressed (brake operating force). ) To increase the braking force of the vehicle. In other words, the brake booster 65 cannot increase the brake operation force sufficiently when the pressure in the other negative pressure chamber is not sufficiently low (that is, when the pressure downstream of the throttle valve is not sufficiently low), and therefore Insufficient braking force may occur.

  On the other hand, in this system, the throttle position sensor 71, the crank position sensor 72, the cooling water temperature sensor 73, and the exhaust passage upstream of the first catalyst 53 (in this example, the exhaust manifold 51) is arranged in an empty space. An air-fuel ratio sensor 74 (hereinafter referred to as “upstream air-fuel ratio sensor 74”), an air-fuel ratio sensor 75 (hereinafter referred to as “upstream air-fuel ratio sensor 74”) disposed in an exhaust passage downstream of the first catalyst 53 and upstream of the second catalyst 54. It is referred to as a “downstream air-fuel ratio sensor 75”), an accelerator opening sensor 76, a vehicle speed sensor 77 as vehicle speed detection means, and an electric control device 80.

  The throttle position sensor 71 detects the opening (throttle valve opening) of the throttle valve 45 and outputs a signal representing the throttle valve opening TA. The crank position sensor 72 outputs a signal having a narrow pulse generated every time the crankshaft 24 rotates 10 ° and a wide pulse generated every time the crankshaft 24 rotates 360 °. This signal represents the engine speed NE. The cooling water temperature sensor 73 detects the temperature of the cooling water circulating in the side wall of the cylinder 21 (cooling water temperature), and outputs a signal representing the cooling water temperature Tw.

  The upstream air-fuel ratio sensor 74 is a limit current type air-fuel ratio sensor. The upstream air-fuel ratio sensor 74 determines the upstream air-fuel ratio based on the oxygen concentration in the detection target gas (in this example, the exhaust gas upstream of the first catalyst 53) and the unburned component (for example, hydrocarbon) concentration of the fuel. A signal indicating the upstream air-fuel ratio A / F is output.

  The downstream air-fuel ratio sensor 75 is an electromotive force type (concentration cell type) air-fuel ratio sensor. The downstream air-fuel ratio sensor 75 detects the downstream air-fuel ratio based on the oxygen concentration in the detection target gas (in this example, the exhaust gas downstream of the first catalyst 53), and indicates a downstream air-fuel ratio A / F. Is output.

  The accelerator opening sensor 76 detects the amount of operation of the accelerator pedal AP operated by the driver, and outputs a signal representing the amount of operation of the accelerator pedal AP (accelerator pedal operation amount) Accp. Note that the accelerator pedal operation amount Accp and the engine speed NE represent the operating state of the engine 10.

  The vehicle speed sensor 77 outputs a predetermined signal generated along with the rotation of the wheel WH. The electric control device 80, which will be described later, calculates the vehicle speed V, which is the speed at which the vehicle moves based on this signal, and determines the start and stop of the vehicle. For example, the stop of the vehicle can be determined when the rotation of the wheel WH is not detected over a predetermined time. The start of the vehicle can be determined when the rotation of the wheel WH is detected in a state where the stop of the vehicle is determined.

  The electric control device 80 includes a CPU 81 connected to each other by a bus, a routine (program) executed by the CPU 81, a ROM 82 that stores tables (lookup tables, maps), constants, and the like in advance, and the CPU 81 temporarily stores data as necessary. The microcomputer 83 includes a RAM 83 that stores data, a backup RAM 84 that stores data while the power is turned on, and retains the stored data while the power is shut off, and an interface 85 including an AD converter. The interface 85 is connected to the sensors 71 to 77, supplies signals from the sensors 71 to 77 to the CPU 81, and in response to an instruction from the CPU 81, the actuator 33a of the variable intake timing device 33 and the actuator 36a of the variable exhaust timing device 36. An instruction signal is transmitted to the igniter 38, the injector 39, the throttle valve actuator 45a, and the bypass flow rate control valve 62.

  Further, the interface 85 of the electric control device 80 is also connected to an air conditioner AC that performs air conditioning of the vehicle interior. The electric machine control device 80 operates in a state where the air conditioner AC is driven by the internal combustion engine 10 in a state in which an air conditioner switch (not shown) operated by a vehicle occupant is ON (driving permission state) and in a state in which the air conditioner switch is ON. It is possible to selectively switch between a state where AC driving is prohibited (driving prohibited state). Note that the air conditioner AC is not driven by the internal combustion engine 10 when the air conditioner switch is OFF.

  The amount of fuel injected from the injector 39 is sucked into the combustion chamber 25 estimated from, for example, the pressure of the air in the intake passage downstream of the throttle valve 45 (the throttle valve downstream pressure Pm) and the engine speed NE. It is calculated from the amount of air (cylinder air amount Mc) and the target air-fuel ratio.

  Here, the throttle valve downstream pressure Pm can be estimated based on, for example, an air model that describes the behavior of air in the intake passage according to a physical law. Since this estimation method is disclosed in detail in Japanese Patent Application Laid-Open No. 2003-184613, Japanese Patent Application Laid-Open No. 2001-41095, and the like, detailed description thereof is omitted in this specification. Further, the throttle valve downstream pressure Pm may be acquired by a pressure sensor provided in the intake passage downstream of the throttle valve 45. The means for obtaining the throttle valve downstream pressure Pm in this way corresponds to the “pressure obtaining means”.

<Overview of operation>
Next, an outline of the operation of the control apparatus for an internal combustion engine configured as described above will be described (see FIG. 9 described later). This control device determines whether or not there is a catalyst warm-up request for promoting warm-up of the first catalyst 53 and the second catalyst 54 (hereinafter sometimes simply referred to as “catalyst”). When it is determined that the spark plug 37 does not spark (specifically, when the coolant temperature Tw is equal to or higher than a predetermined threshold temperature α), the timing at which the spark plug 37 generates a spark in the combustion chamber 25 (ignition timing), and the throttle valve 45 The normal control of the opening degree (throttle valve opening degree) is performed. On the other hand, when it is determined that there is a catalyst warm-up request at the time of cold start or the like (specifically, when the cooling water temperature Tw is lower than the threshold temperature α), the control device first increases the temperature of the catalyst ( The first catalyst warm-up control is performed for the ignition timing and the throttle valve opening, with the main purpose of promoting warm-up).

  During the execution of the first catalyst warm-up control (and when there is a catalyst warm-up request), the control device determines whether or not there is a negative pressure increase request for decreasing the throttle valve downstream pressure, and there is a negative pressure increase request. (Specifically, when the vehicle starts), the ignition timing and throttle are mainly aimed at eliminating the braking force deficiency by reducing the downstream pressure of the throttle valve (increasing the negative pressure). Negative pressure increase control is performed for the valve opening.

  During this negative pressure increase control (and when there is a catalyst warm-up request), when a predetermined short time has elapsed, this control device takes into account both the warm-up promotion of the catalyst and the elimination of insufficient braking force. Second catalyst warm-up control is performed for the ignition timing and the throttle valve opening.

  When the vehicle is stopped during the execution of the second catalyst warm-up control (and when there is a catalyst warm-up request), the control device performs the first catalyst warm-up control on the ignition timing and the throttle valve opening. Do it again.

  When it is determined that there is no catalyst warm-up request during execution of any of the above controls other than the normal control (specifically, when the coolant temperature Tw is equal to or higher than the threshold temperature α), this control is performed. The apparatus performs the normal control for the ignition timing and the throttle valve opening. The above-described normal control, first catalyst warm-up control, negative pressure increase control, and second catalyst warm-up control regarding the ignition timing and throttle valve opening will be described in detail in the following <Details of operation> section. .

<Details of operation>
Next, the actual operation of the electric control device 80 will be described with reference to the routines shown in the flowcharts of FIGS. 2 to 8 and the time chart of FIG. FIG. 9 shows that after cold start (that is, when there is a catalyst warm-up request), the vehicle starts in the idling state (Accp = 0) at time t1 (creep traveling or downhill traveling), and from time t1 to time t1. The example shows a case where the vehicle continues to move in the idling state until t6, the vehicle stops at time t6, and the coolant temperature Tw reaches the threshold temperature α at time t7 and the catalyst warm-up request is no longer required. . First, setting and changing various flags will be described.

  The CPU 81 of the electric control device 80 executes the “catalyst warm-up determination” routine shown in FIG. 2 every elapse of a predetermined calculation cycle (8 ms in this example). The execution of the routine of FIG. 2 corresponds to the achievement of part of the function of the warm-up request determination unit.

  Therefore, when the predetermined timing comes, the CPU 81 starts the process from step 200 and proceeds to step 205 to determine whether or not the coolant temperature Tw detected by the coolant temperature sensor 73 is lower than the threshold temperature α. To do. If the CPU 81 determines “Yes” in step 205, it proceeds to step 210 and sets the warm-up flag Xd to “1”, whereas if it determines “No”, it proceeds to step 215 and proceeds to step 215. Xd is set to “0”, the negative pressure increase flag Xp and the negative pressure hold flag Xk are set to “0”, the air conditioner flag Xa is set to “1”, and the routine proceeds to step 295. Is temporarily terminated.

  Here, the warm-up flag Xd indicates that there is a catalyst warm-up request when the value is “1”, and indicates that there is no catalyst warm-up request when the value is “0”. Specifically, in FIG. 9, Xd = “1” is set since Tw <α before time t7, and Xd = “0” is set since Tw ≧ α after time t7.

  The negative pressure increase flag Xp indicates that the negative pressure increase control is being performed when the value is “1”, and that the negative pressure increase control is not being performed when the value is “0”. Specifically, in FIG. 9, Xp = “1” is set only at times t1 to t4 when the negative pressure increase control is executed, and Xp = “0” is set in other periods.

  The negative pressure holding flag Xk indicates that the second catalyst warm-up control is being performed when the value is “1”, and indicates that the second catalyst warm-up control is not being performed when the value is “0”. Specifically, in FIG. 9, Xk = “1” is set only at times t4 to t6 when the second catalyst warm-up control is executed, and Xk = “0” is set in other periods.

  When the value of the air conditioner flag Xa is “1”, it indicates that the air conditioner AC is in the “driving permitted state”, and when the value is “0”, the air conditioner AC is in the “driving prohibited state” described above. Indicates. Specifically, in FIG. 9, Xa = “0” is set only at times t1 to t4 when the negative pressure increase control is executed, and Xa = “1” is set in other periods.

  As can be understood from step 215, when the warm-up flag Xd = “0” (when there is no catalyst warm-up request), the negative pressure increase flag Xp and the negative pressure hold flag Xk are fixed to “0”, and the air conditioner flag Xa is fixed to “1”.

  Further, the CPU 81 of the electric control device 80 is configured to execute the “movement determination” routine shown in FIG. 3 following the routine of FIG. The execution of the routine of FIG. 3 corresponds to the achievement of part of the functions of the start determination means and the stop determination means.

  Therefore, when the execution of the routine of FIG. 2 is completed, the CPU 81 starts the process from step 300 and proceeds to step 305 to determine whether or not the movement flag Xm is “0”. Here, the movement flag Xm indicates that the vehicle is moving when the value is “1”, and indicates that the vehicle is stopped when the value is “0”.

  When determining “Yes” in step 305 (Xm = 0), the CPU 81 proceeds to step 310 to determine whether or not the vehicle has started based on the output signal of the vehicle speed sensor 77 and determines “Yes”. If so, the process proceeds to step 315, and the movement flag Xm is changed from “0” to “1”. On the other hand, when determining “No” in step 305 (Xm = 1), the CPU 81 proceeds to step 320 to determine whether or not the vehicle has stopped based on the output signal of the vehicle speed sensor 77, and “Yes”. If it is determined, the process proceeds to step 325 and the movement flag Xm is changed from “1” to “0”.

  Specifically, in FIG. 9, Xm is changed from “0” to “1” at time t1 when the vehicle starts, and Xm = “1” is maintained while the vehicle is moving (time t1 to t6). Xm is changed from “1” to “0” at time t6 when the vehicle stops, and Xm = “0” is set while the vehicle is stopped (before time t1 and after time t6).

  Further, the CPU 81 of the electric control device 80 executes the “idle determination” routine shown in FIG. 4 following the routine of FIG. The execution of the routine of FIG. 4 corresponds to the achievement of part of the function of the idling determination means.

  Therefore, when the execution of the routine of FIG. 3 is completed, the CPU 81 starts the process from step 400 and proceeds to step 405, and whether or not the accelerator pedal operation amount Accp detected by the accelerator opening sensor 76 is “0”. Determine whether. When determining “Yes” in step 405, the CPU 81 proceeds to step 410 to set the idle flag Xi to “1”, whereas when determining “No”, the CPU 81 proceeds to step 415 to set the idle flag Xi. Set to “0”.

  Here, when the value of the idle flag Xi is “1”, it indicates that it is in the idling state, and when the value is “0”, it indicates that it is not in the idling state. Specifically, in FIG. 9, since it is in an idling state from beginning to end, Xi = “1” is maintained.

  Further, the CPU 81 of the electric control device 80 executes the “negative pressure increase determination” routine shown in FIG. 5 following the routine of FIG. The execution of the routine of FIG. 5 corresponds to the achievement of part of the function of the increase request determination unit.

  Therefore, when the execution of the routine of FIG. 4 is completed, the CPU 81 starts the process from step 500 and proceeds to step 505 to determine whether or not the negative pressure increase flag Xp described above is “0”. When determining “Yes” in step 505, the CPU 81 proceeds to step 510 to determine whether or not a negative pressure increase control start condition is satisfied.

  The negative pressure increase control start condition is a catalyst warm-up request (Xd = “1”), an idling state (Xi = “1”), and the vehicle starts (Xm changes from “0” to “1”). ”). Here, “being in the idling state” is included because it is very unlikely that the brake operation is performed when the idling state is not established (that is, when the accelerator pedal AP is depressed). . Note that “the throttle valve downstream pressure Pm is higher than a predetermined pressure (for example, a reference pressure Pref described later)” may be added to the negative pressure increase control start condition.

  When the negative pressure increase control start condition is satisfied (time t1 in FIG. 9), the CPU 81 proceeds to step 515 to change the negative pressure increase flag Xp from “0” to “1” and set the air conditioner flag Xa to “0”. ”.

  On the other hand, when determining “No” in step 505 (Xp = 1), the CPU 81 proceeds to step 520 to determine whether or not the negative pressure increase control end condition is satisfied. The negative pressure increase control end condition is satisfied when the time T1 has elapsed from the start of the negative pressure increase control (time t4 in FIG. 9). Here, during the time T1, the negative pressure chamber pressure of the brake booster 65 appropriately sets the braking force from the time point when switching from the first catalyst warm-up control described later in detail to negative pressure increase control (time t1 in FIG. 9). It is a time (for example, about 1 to 2 seconds) required to decrease to such an extent that it can be increased, and can be obtained by experiment, simulation, or the like. The negative pressure increase control end condition may be replaced with “the negative pressure chamber pressure of the brake booster 65 is lower than a predetermined pressure”.

  When the negative pressure increase control end condition is satisfied (time t4 in FIG. 9), the CPU 81 proceeds to step 525 to change the negative pressure increase flag Xp from “1” to “0” and set the air conditioner flag Xa to “1”. ”. As described above, the air conditioner flag Xa is set to “0” only when the negative pressure increase control is being executed (Xp = “1”) (that is, “driving prohibited state”), and when the negative pressure increase control is not being executed (Xp = “ 0 ”) is set to“ 1 ”(that is,“ driving permitted state ”).

  Further, the CPU 81 of the electric control device 80 executes the “negative pressure holding determination” routine shown in FIG. 6 following the routine of FIG. The execution of the routine of FIG. 6 corresponds to the achievement of part of the function of the second catalyst warm-up control means.

  Therefore, when the execution of the routine of FIG. 5 ends, the CPU 81 starts the process from step 600 and proceeds to step 605 to determine whether or not the negative pressure holding flag Xk described above is “0”. When determining “Yes” in step 605, the CPU 81 proceeds to step 610 to determine whether or not the second catalyst warm-up control start condition (corresponding to the “predetermined condition”) is satisfied.

  The second catalyst warm-up control start condition is that there is a catalyst warm-up request (Xd = “1”) and the negative pressure increase control end condition in step 520 is satisfied (Xp is changed from “1” to “0”). Change). When the second catalyst warm-up control start condition is satisfied (time t4 in FIG. 9), the CPU 81 proceeds to step 615 and changes the negative pressure holding flag Xk from “0” to “1”.

  On the other hand, when it determines with "No" in step 605 (Xk = 1), CPU81 progresses to step 620 and determines the presence or absence of 2nd catalyst warm-up control completion conditions. The second catalyst warm-up control end condition is satisfied when the vehicle stops (Xm changes from “1” to “0”). When the second catalyst warm-up control end condition is satisfied (time t6 in FIG. 9), the CPU 81 proceeds to step 625 and changes the negative pressure holding flag Xk from “1” to “0”.

  The setting / changing of various flags has been described above. Next, ignition timing control and throttle valve opening control performed based on the state of the flag will be described. In the following description, a table represented as MapX (a, b,...) Means a table that defines the relationship between the variable a, the variable b, the variable. In addition, the value X is obtained based on the table MapX (a, b, ...). The value X is obtained by calculating the current variable a, the current variable b, the current variable ..., and the table MapX (a, b, ...) It means that it is determined (determined) based on.

  The CPU 81 of the electric control device 80 executes the “ignition timing control” routine shown in FIG. 7 following the routine of FIG. The execution of the routine of FIG. 7 corresponds to the achievement of some of the functions of the normal control means, the first and second catalyst warm-up control means, and the negative pressure increase control means. is doing.

  Therefore, when the execution of the routine of FIG. 6 is completed, the CPU 81 starts the process from step 700 and proceeds to step 702 to obtain the normal ignition timing θ0 based on the table Mapθ0 (Accp, NE). This normal ignition timing θ0 is set to an optimal ignition timing (for example, MBT) in the current operating state from the viewpoint of output torque and fuel consumption in the fully warmed-up state. The normal ignition timing θ0 may be set on the retard side from the MBT in the idling state.

  Subsequently, the CPU 81 proceeds to step 704 to determine whether or not there is a catalyst warm-up request (Xd = “1” or “0”). When it is determined that there is no catalyst warm-up request (in step 704). “No”), the routine proceeds to step 706, where the ignition timing θ is set to a timing equal to the normal ignition timing θ0 (refer to time t7 and thereafter in FIG. 9). Note that, as shown immediately after time t7 in FIG. 9, in a predetermined short period of time immediately after the catalyst warm-up request is changed (Xd = “1”) to not (Xd = “0”), The ignition timing θ may be gradually changed from the current value toward the normal ignition timing θ0. Control in which the ignition timing θ is thus set to the normal retardation amount θ0 (including control of the throttle valve opening described later) is referred to as “normal control”.

  Hereinafter, a case where it is determined that there is a catalyst warm-up request (“Yes” in step 704) will be described (see FIG. 9 before time t7). In this case, the CPU 81 proceeds to step 708 to obtain the provisional retardation amount θA based on the table MapθA (Tw). The provisional retardation amount θA is a retardation amount from the normal ignition timing θ0 with respect to the ignition timing θ, which is determined from the viewpoint of promoting warm-up of the catalyst. In FIG. 9, for the sake of convenience of explanation, the provisional retardation amount θA is shown to be constant even though the coolant temperature Tw increases with the passage of time (the advance amount θB described later is also described). The same).

  Next, the CPU 81 proceeds to step 710 to determine whether or not the negative pressure increase flag Xp = “0” and the negative pressure holding flag Xk = “0”. First, a case where Xp = Xk = “0” will be described (refer to FIG. 9 before time t1). In this case (“Yes” in step 710), the CPU 81 proceeds to step 712 and sets the retardation amount θdelay to a value equal to the provisional retardation amount θA. The retardation amount θdelay is a final retardation amount that is added to the normal retardation amount θ0.

  That is, the CPU 81 proceeds to step 714 to set the ignition timing θ from the normal retard amount θ0 to the retard side by the retard amount θdelay, and then in step 716, the spark plug 37 is set to the spark plug 37 at the ignition timing θ. The igniter 38 is instructed to generate a spark.

  As described above, the ignition timing θ is set to a timing (θ0 + θA, corresponding to the “first ignition timing”) that is retarded by the provisional retardation amount θA from the normal retardation amount θ0 (throttle valve opening described later). (Including control of the degree) is referred to as “first catalyst warm-up control”. As described above, as long as there is a catalyst warm-up request (Xd = “1”) and Xp = Xk = “0”, “first catalyst warm-up control” is repeatedly executed (in FIG. 9, at time t1). See previous).

  Next, during execution of the “first catalyst warm-up control”, if the negative pressure increase control start condition shown in step 510 of FIG. 5 is satisfied (Xp changes from “0” to “1”, Xk is Will be described (refer to time t1 in FIG. 9). In this case, when the CPU 81 proceeds to step 710, it determines “No”, proceeds to step 718, and determines whether Xp = “1”.

  In this case, since Xp = “1”, the CPU 81 makes a “Yes” determination at step 718 to proceed to step 720, where time T2 (<T1) (see FIG. 9) has elapsed from the start of the negative pressure increase control. It is determined whether or not it has elapsed.

  Until the time T2 elapses from the start of the negative pressure increase control (refer to times t1 to t2 in FIG. 9), the CPU 81 continues to determine “No” in step 720, proceeds to step 722, and delays. The angle return amount θadv is set to “0”. Here, the retard return amount θadv is an advance amount from (θ0 + θA) with respect to the ignition timing θ, which is determined from the viewpoint of increasing the negative pressure.

  On the other hand, after the time T2 has elapsed (see time t2 and thereafter in FIG. 9), the CPU 81 continues to determine “Yes” in step 720, and proceeds to step 724 to set the retard return amount θadv at the present time. The value gradually changes from the value to the provisional retardation amount θA. As a result, the retard return amount θadv is maintained at “0” until the time T2 elapses from the start of the negative pressure increase control (see time t1 to t2 in FIG. 9), and the time T2 elapses. In a later short period, gradually increases from “0” toward the provisional retardation amount θA (refer to time t2 and thereafter in FIG. 9), and after the retardation return amount θadv reaches the provisional retardation amount θA Is maintained at the provisional retardation amount θA (see times t3 to t4 in FIG. 9).

  In step 726, the CPU 81 sets the retardation amount θdelay to (θA−θadv). As a result, the retardation amount θdelay is maintained at θA from the start of the negative pressure increase control until the time T2 elapses (time t1 to t2), and from 0A to “0” in a short period after the time T2 elapses. "Is gradually decreased toward time (after time t2), and is maintained at" 0 "after time θadv reaches θA (time t3 to time t4). That is, the ignition timing θ (= θ0 + θdelay) set in step 714 and instructed to fire in step 716 is continuously continued until the time T2 elapses from the start of the negative pressure increase control. (Θ0 + θA) is maintained at the same time (time t1 to t2), and gradually moves from (θ0 + θA) toward the normal ignition timing θ0 in a short period after time T2 has elapsed (time t2). Thereafter, the normal ignition timing θ0 is maintained after θadv reaches θA (time t3 to t4).

  It should be noted that the ignition timing θ is continuously maintained from the start of the negative pressure increasing control until the time T2 elapses (time t1 to t2 in FIG. 9) and maintained at the same (θ0 + θA) as during the first catalyst warm-up control. This is based on the following reason. That is, as will be described later, when the throttle valve opening degree TA decreases stepwise from (TA0 + TAA) to TA0 at the start of negative pressure increase control (time t1 in FIG. 9), the throttle valve downstream pressure Pm increases. It decreases with a delay from the start of control (see FIG. 9). That is, the in-cylinder air amount (and the fuel amount) also decreases with a delay from the start of the negative pressure increase control. Therefore, if the ignition timing θ is advanced immediately at the start of the negative pressure increase control, the output torque becomes excessive and torque fluctuation occurs in a short period from the start of the negative pressure increase control. In order to suppress the occurrence of this torque fluctuation, the advance start timing of the ignition timing θ is delayed until the in-cylinder air amount approaches the air amount corresponding to the throttle valve opening TA = TA0 (ignition timing delay process).

  In this way, the control (including the throttle valve opening control described later) in which the ignition timing θ is set (advanced) to the normal ignition timing θ0 (corresponding to the “second ignition timing”) is set to “negative pressure increase”. This is referred to as “control”. As described above, as long as there is a catalyst warm-up request and Xp = “1” and Xk = “0”, the “negative pressure increase control” is repeatedly executed (see times t1 to t4 in FIG. 9). .

  Next, during the execution of the “negative pressure increase control”, when the negative pressure increase control end condition shown in step 520 of FIG. 5 is satisfied, that is, the second catalyst warm-up control shown in step 610 of FIG. A case where the start condition is satisfied (Xp changes from “1” to “0” and Xk changes from “0” to “1”) will be described (see time t4 in FIG. 9). In this case, when the CPU 81 proceeds to step 718, it determines “No”, proceeds to step 728, and determines whether or not it is in an idling state (Xi = “1” or “0”).

  First, as shown in FIG. 9, a case where the vehicle is idling from start to finish will be described. In this case, since Xi = “1”, the CPU 81 makes a “Yes” determination at step 728 to proceed to step 730 to obtain the advance amount θB based on the table MapθB (Tw, NE). As will be described later, the advance amount θB is a target amount that gradually changes and approaches the retard return amount θadv. Thus, the advance amount θB is set to a smaller value as the coolant temperature Tw is higher and the engine speed NE is higher. Further, the advance amount θB is normally set to a value smaller than the provisional retard amount θA.

  Subsequently, the CPU 81 proceeds to step 734 to gradually change the retard return amount θadv toward the advance amount θB. As a result, the retard return amount θadv gradually decreases from θA to θB in a short period from the start of the second catalyst warm-up control (time t4 in FIG. 9) (time t4 in FIG. 9). After that, after θadv reaches θB, it is maintained at θB (refer to times t5 to t6 in FIG. 9).

  When the CPU 81 proceeds to step 736, it determines whether or not the retard return amount θadv is larger than the provisional retard amount θA. If “Yes”, the CPU 81 proceeds to step 738 and sets θadv equal to θA. Restrict.

  Next, the CPU 81 proceeds to step 740 and sets the retardation amount θdelay to (θA−θadv) as in step 726. As a result, the retard amount θdelay gradually decreases from “0” toward (θA−θB) in a short period from the start of the second catalyst warm-up control (after time t4), and θadv becomes θB. After reaching, (θA−θB) is maintained (time t5 to t6). That is, the ignition timing θ (= θ0 + θdelay) set in step 714 and instructed to fire in step 716 is directed from the normal ignition timing θ0 to (θ0 + θA−θB) in a short period from the start of the second catalyst warm-up control. The angle gradually moves to the retard side (after time t4), and after θadv reaches θB, it is maintained at (θ0 + θA−θB) (time t5 to t6).

  As described above, the control (including the throttle valve opening control described later) in which the ignition timing θ is set (retarded) to (θ0 + θA−θB) (corresponding to the “third ignition timing”) is referred to as “second”. This is referred to as “catalyst warm-up control”. As described above, as long as there is a catalyst warm-up request, and Xp = “0” and Xk = “1”, “second catalyst warm-up control” is repeatedly executed (in FIG. 9, time t4 to t6). reference).

  Next, during execution of the “second catalyst warm-up control”, when the second catalyst warm-up control end condition shown in step 620 of FIG. 6 is satisfied (Xk changes from “1” to “0”, Xp is maintained at “0”) (see time t6 in FIG. 9). In this case, when the CPU 81 proceeds to step 710, it determines “Yes” and executes the first catalyst warm-up control described above again. That is, the ignition timing θ is changed (retarded) from (θ0 + θA−θB) to (θ0 + θA).

  In addition, as shown immediately after time t6 in FIG. 9, in a predetermined short period immediately after the second catalyst warm-up control is changed to the first catalyst warm-up control, the ignition timing θ is determined from the current value ( It may be gradually changed toward θ0 + θA). This first catalyst warm-up control is repeatedly executed as long as there is a catalyst warm-up request (and as long as Xp = Xk = “0”) (see times t6 to t7 in FIG. 9).

  Next, a description will be given of a case where the catalyst warm-up request is lost during the execution of the “first catalyst warm-up control” (Xd changes from “1” to “0”) (see time t7 in FIG. 9). ). In this case, when the CPU 81 proceeds to step 704, it determines “No” and executes the above-described normal control. That is, the ignition timing θ is changed (advanced) from (θ0 + θA) to the normal ignition timing θ0. This normal control is repeatedly executed unless there is a catalyst warm-up request (Xd = “0”) (refer to time t7 and thereafter in FIG. 9).

  Further, the CPU 81 of the electric control device 80 executes the “throttle valve opening degree control” routine shown in FIG. 8 following the routine of FIG. The execution of the routine of FIG. 8 corresponds to the achievement of some of the functions of the normal control means, the first and second catalyst warm-up control means, and the negative pressure increase control means. is doing.

  Therefore, when the execution of the routine of FIG. 7 is completed, the CPU 81 starts the process from step 800 and proceeds to step 805, and sets the normal throttle valve opening TA0 based on the table MapTA0 (Accp, NE, Tw, Xa). Ask. The normal throttle valve opening TA0 is obtained by controlling the throttle valve opening to TA0 so that the amount of air (air mixture) required to generate the torque required for the internal combustion engine 10 (torque corresponding to Accp) is obtained. It is set to be supplied to the combustion chamber 25. TA0 is set to a smaller opening as the coolant temperature Tw is higher. In addition, TA0 is set to a larger value than when the air conditioner flag Xa = 1 (driving permitted state) and when Xa = 0 (driving prohibited state).

  Here, the reason why TA0 is set to a larger value in the drive permission state than in the drive inhibition state is as follows. That is, while the air conditioner AC is being driven, a part of the power of the internal combustion engine 10 is consumed for driving the air conditioner AC, so that the power of the internal combustion engine 10 that can be used for driving the vehicle is reduced. Therefore, when the air conditioner AC is being driven (Xa = “1”), in order to compensate for the reduction in power, the normal throttle valve opening is smaller than when the air conditioner AC is not being driven (Xa = “0”). Set TA0 (thus, throttle valve opening TA) to a large value to increase the combustion energy.

  Further, the reason why TA0 is set to a smaller opening degree as the cooling water temperature Tw is higher is as follows. That is, when the coolant temperature Tw is low, the frictional resistance against the movement of each movable member in the internal combustion engine 10 increases. Accordingly, the amount consumed by the frictional resistance in the power of the internal combustion engine 10 increases, and the power of the internal combustion engine 10 that can be used for driving the vehicle decreases. Therefore, the lower the coolant temperature Tw, the larger the normal throttle valve opening TA0 (and hence the throttle valve opening TA), and the combustion energy is increased.

  Subsequently, the CPU 81 proceeds to step 810 to determine whether or not there is a catalyst warm-up request (Xd = “1” or “0”). When it is determined that there is no catalyst warm-up request (step 810). In step 815, the throttle valve opening TA is set to an opening equal to the normal throttle valve opening TA0 (refer to time t7 and thereafter in FIG. 9). Note that, as shown immediately after time t7 in FIG. 9, in a predetermined short period of time immediately after the catalyst warm-up request is changed (Xd = “1”) to not (Xd = “0”), The throttle valve opening TA may be gradually changed from the current value toward the normal throttle valve opening TA0.

  Hereinafter, a case where it is determined that there is a catalyst warm-up request (“Yes” in step 810) will be described (see FIG. 9 before time t7). In this case, the CPU 81 proceeds to step 820 to determine whether or not negative pressure increase control is being executed (Xp = “1” or “0”), and when negative pressure increase control is not being executed (in FIG. 9, at time t1). In step 820, the determination is “Yes” and the process proceeds to step 825, where the addition amount TAadd is obtained based on the table MapTAadd (θdelay). This added amount TAadd is an opening that is added to the normal throttle valve opening TA0 in order to compensate for the decrease in output torque caused by the ignition timing θ being retarded from the normal ignition timing θ0 from the viewpoint of promoting catalyst warm-up. Degree.

  Thereby, when the negative pressure increase control is not being executed, the addition amount TAadd is determined so as to be interlocked with the change in the retardation amount θdelay. Specifically, the addition amount TAadd is set to “0” when θdelay = “0”, and is set to a larger value (> 0) as θdelay (> 0) is larger. On the other hand, when the negative pressure increase control is being executed (see times t1 to t4 in FIG. 9), the CPU 81 makes a “No” determination at step 820 to proceed to step 830 to set the addition amount TAadd to “0”. To fix.

  Next, the CPU 81 proceeds to step 835 to set the throttle valve opening TA to the opening obtained by adding the additional amount TAadd to the normal throttle valve opening TA0, and in step 840, the throttle valve opening TA is controlled to TA. To instruct the throttle valve actuator 45a.

  As a result, when the increase control is not being executed (see the period excluding times t1 to t4 in FIG. 9), the larger the amount by which the ignition timing θ is retarded from the normal ignition timing θ0, the greater the throttle valve opening TA. The amount added from the normal throttle valve opening TA0 becomes larger. Hereinafter, such a relationship between the ignition timing and the throttle valve opening is also referred to as “linkage between the ignition timing and the throttle valve opening”. Specifically, during the first catalyst warm-up control (refer to t6 to t7 before time t1 in FIG. 9), TA = (TA + TAA) (corresponding to the “first throttle valve opening”) is controlled. During the second catalyst warm-up control (refer to times t4 to t6 in FIG. 9), TA = (TA + TAB) (corresponding to the “third throttle valve opening”) is controlled (TAA> TAB). By such “interlocking of ignition timing and throttle valve opening”, the above-described decrease in output torque can be reliably compensated.

  On the other hand, when the negative pressure increase control is being executed (see times t1 to t4 in FIG. 9), the throttle valve opening TA is equal to the normal throttle valve opening TA0 (the “second throttle valve opening”). Corresponding). As a result, at the start of the negative pressure increase control (see time t1 in FIG. 9), the throttle valve opening TA decreases stepwise from (TA0 + TAadd) to TA0. That is, due to the “ignition timing delay process” described above, “interlocking of the ignition timing and the throttle valve opening” is achieved only during the period related to the “ignition timing delay process” (time t1 to t3 in FIG. 9). However, in the remaining period during execution of the negative pressure increasing control (time t3 to t4 in FIG. 9), “interlocking of ignition timing and throttle valve opening” is achieved.

  As described above, as shown in FIG. 9, the case where there is a catalyst warm-up request and the idling state (Xi = 1) from start to finish has been described. Next, as shown in FIG. 10 corresponding to FIG. 9, when there is a catalyst warm-up request, a period (Xi = 0) that is not in an idling state occurs when the accelerator pedal AP is operated halfway. explain. FIG. 10 shows a case in which the period not in the idling state is from time tA during the negative pressure increase control to time tB during the second catalyst warm-up control.

  When Xi = “0” during the second catalyst warm-up control (Xd = “1”, Xp = “0”, Xk = “1”), the CPU 81 that repeatedly executes the routine of FIG. When the routine proceeds to step 728, it is determined as “No” and the routine proceeds to step 732, where the advance amount θB is set to “0”. As a result, the retard return amount θadv decreases toward “0”. In FIG. 10, after time t4, the retard return amount θadv decreases toward “0” and is maintained at “0” after θadv reaches “0”.

  On the other hand, if Xi is changed from “1” to “0” during the second catalyst warm-up control, the advance amount θB is set in step 730, and as a result, the retard return amount θadv is , ΘB> 0. In FIG. 10, after time tB, the retard return amount θadv increases toward θB> 0, and is maintained at θB after θadv reaches θB.

  That is, in FIG. 10, after time t4, the ignition timing θ moves from the normal ignition timing θ0 toward (θ0 + θA) toward the retard side, and is maintained at (θ0 + θA) after θadv reaches “0”. Is done. After time tB, the ignition timing θ moves from (θ0 + θA) toward (θ0 + θA−θB) toward the advance side, and is maintained at (θ0 + θA−θB) after θadv reaches θB.

  Since the ignition timing θ changes in this way, the throttle valve opening TA increases from the normal throttle valve opening TA0 toward (TA0 + TAA) after time t4 by “interlocking of ignition timing and throttle valve opening”. Then, after θadv reaches “0”, it is maintained at (TA0 + TAA). After time tB, the throttle valve opening TA decreases from (TA0 + TAA) toward (TA0 + TAB), and is maintained at (TA0 + TAB) after θadv reaches θB.

  Thus, when the second catalyst warm-up control is not in the idling state, the ignition timing θ is equal to the timing (θ0 + θA) during the first catalyst warm-up control (therefore, the second time in the idling state). It is set at a timing during catalyst warm-up control (timing on the retarded side relative to θ0 + θA−θB), and the throttle valve opening TA is equal to the opening (TA0 + TAA) during the first catalyst warm-up control (accordingly) The opening is larger than the opening (TA0 + TAB) during the second catalyst warm-up control in the idling state.

  As described above, during the first catalyst warm-up control (in FIG. 9, before time t1, t6 to t7), the ignition timing θ is substantially retarded from the normal ignition timing θ0 (θ0 + θA). The throttle valve opening TA is set to an opening (TA0 + TAA) larger than the normal throttle valve opening TA0. As a result, the throttle valve downstream pressure Pm is maintained at a relatively high value Pm1 (pressure corresponding to the first throttle valve opening) corresponding to TA = (TA0 + TAA).

  Thus, when the ignition timing θ is retarded, the combustion of the air-fuel mixture can continue even after the exhaust valve 35 is opened in the exhaust stroke (so-called “post-combustion”). In addition, when the throttle valve opening degree TA is increased, the in-cylinder air amount (and the fuel amount) is increased and the combustion energy is increased. As a result, the temperature of the exhaust gas can be increased as compared with the normal control, and as a result, the temperature of the catalyst can be brought close to the activation temperature quickly.

  During negative pressure increase control (time t1 to t4 in FIG. 9), the ignition timing θ is set to a timing equal to the normal ignition timing θ0, and the throttle valve opening TA is equal to the normal throttle valve opening TA0. Set to As a result, the throttle valve opening TA is decreased, and the throttle valve downstream pressure Pm is shifted from the value Pm1 to a relatively low value Pm2 (pressure corresponding to the second throttle valve opening) corresponding to TA = TA0. Decrease. As a result, Pm has already converged to the value Pm2 until the time T1 (about 1 to 2 seconds) elapses from the start of the negative pressure increase control. As a result, the negative pressure increase control end point (time t4 in FIG. 9). ), The negative pressure chamber pressure in the brake booster 65 is also a sufficiently low value not more than the value Pm2. Therefore, the shortage of braking force can be resolved at the end of the negative pressure increase control. In other words, a sufficient braking force can be exerted immediately after the vehicle starts.

  Further, during the second catalyst warm-up control (time t4 to t6 in FIG. 9), the ignition timing θ is between the timing during the first catalyst warm-up control (θ0 + θA) and the timing θ0 during the negative pressure increase control. (Θ0 + θA−θB), and the throttle valve opening TA is the opening between the opening during the first catalyst warm-up control (TA0 + TAA) and the opening TA0 during the negative pressure increase control (TA0 + TAB) Set to As a result, the throttle valve opening TA increases, and the throttle valve downstream pressure Pm is adjusted to a value Pref (corresponding to the “predetermined pressure”) that is higher than the value Pm2 and lower than the value Pm1.

  This value Pref can be sufficient for the above-described “replenishment of negative pressure” even when the brake operation is performed relatively frequently during the vehicle running in the second catalyst warm-up control, and the above-described braking force is insufficient. It is a value within a range of pressure sufficiently low that generation can be sufficiently suppressed (particularly, an upper limit value within the range).

  Thus, during the second catalyst warm-up control, the ignition timing θ is set to the retard side by (θA−θB) than during the negative pressure increase control. Therefore, compared with the case where the negative pressure increase control is continued, the temperature of the exhaust gas can be increased and the temperature of the catalyst can be brought close to the activation temperature quickly. In addition, the throttle valve opening TA is set to be smaller by (TAA−TAB) than during the first catalyst warm-up control. Therefore, the throttle valve downstream pressure Pm can be maintained at a lower pressure (= Pref) than when the first catalyst warm-up control is started and executed after the negative pressure increase control is stopped. Therefore, even if the brake operation is performed relatively frequently during the traveling of the vehicle under the second catalyst warm-up control, the occurrence of insufficient braking force can be suppressed.

  Further, during the negative pressure increase control (accordingly, about 1 to 2 seconds), the driving of the air conditioner AC by the internal combustion engine 10 is prohibited, and during the subsequent second catalyst warm-up control, the driving of the air conditioner AC by the internal combustion engine 10 is prohibited. Permitted (executed when the air conditioner switch is ON) (see steps 515 and 525 in FIG. 5). As described above, when the air conditioner AC is not driven, the throttle valve opening degree TA is made smaller than when the air conditioner AC is driven. Therefore, the throttle valve downstream pressure Pm becomes lower than that during driving of the air conditioner AC, and the above-described “replenishment of negative pressure” can be performed more quickly. Further, even if the driving of the air conditioner AC is interrupted for a relatively short time (for example, about 1 to 2 seconds), the air conditioning control in the passenger compartment is hardly adversely affected. Therefore, by prohibiting the driving of the air conditioner AC during the negative pressure increase control, the above-described “replenishment of negative pressure” can be more reliably achieved during the negative pressure increase control without adversely affecting the air conditioning control. .

  In addition, during the second catalyst warm-up control (and when Xa = “1”), the advance amount θB is set to a smaller value as the coolant temperature Tw is higher and the engine speed NE is larger. (See step 730 in FIG. 7). In other words, the ignition timing θ during the second catalyst warm-up control is set to be more retarded as the coolant temperature Tw is higher and the engine speed NE is higher. Accordingly, the “interlocking of the ignition timing and the throttle valve opening” indicates that the throttle valve opening TA during the second catalyst warm-up control is larger as the coolant temperature Tw is higher and the engine speed NE is higher. Set to This is based on the following reason.

  That is, under the condition that the throttle valve opening TA is constant, the throttle valve downstream pressure Pm becomes lower as the engine speed NE becomes larger. This means that even if the ignition timing θ is set to a more retarded side as the engine speed NE increases (thus, even if the throttle valve opening TA is set to a larger value), the throttle valve downstream pressure Pm This means that it can be maintained at the above value Pref (or below Pref).

  Further, as described above, as the coolant temperature Tw increases, the throttle valve opening degree TA is made smaller and the throttle valve downstream pressure Pm becomes lower. This means that even if the ignition timing θ is set to a more retarded side as the coolant temperature Tw becomes higher (thus setting the throttle valve opening TA to a larger value), the throttle valve downstream pressure Pm This means that it can be maintained at the above value Pref (or below Pref).

  From the above, during the second catalyst warm-up control, the ignition timing θ is set to the more retarded side and the throttle valve opening TA is more increased as the engine speed NE is higher or the coolant temperature Tw is higher. A large opening is set. Thus, while maintaining the throttle valve downstream pressure Pm at the above value Pref, the ignition timing θ can be set to the retard side as much as possible, and the temperature of the catalyst can be brought close to the activation temperature as early as possible.

  Further, during the second catalyst warm-up control, θadv is limited by θA so that the retard return amount θadv does not exceed the provisional retard amount θA (see steps 736 and 738 in FIG. 7). That is, the ignition timing θ during the second catalyst warm-up control is not advanced from the normal ignition timing θ0 (thus, the throttle valve opening TA during the second catalyst warm-up control is greater than the normal throttle valve TA0). It is set so that the opening is not small. As a result, during the second catalyst warm-up control, it is possible to avoid a situation in which the ignition timing θ is more advanced than the normal ignition timing θ0 and the catalyst warm-up cannot be promoted.

  In addition, when the second catalyst warm-up control is not in the idling state, the ignition timing θ is equal to the timing (θ0 + θA) during the first catalyst warm-up control (thus, the throttle valve opening TA is 1 Opening degree during catalyst warm-up control (opening equal to TA0 + TAA) is set. As a result, when the brake operation is very unlikely (when not in an idling state), the acceleration of catalyst warm-up is prioritized over the elimination of insufficient braking force of the vehicle, and the ignition timing θ is retarded as much as possible. Set to the side. As a result, the temperature of the catalyst can be brought close to the activation temperature as early as possible.

  As described above, according to the embodiment of the control device for an internal combustion engine according to the present invention, when there is a catalyst warm-up request, the first catalyst warm-up control that has been executed is stopped and the negative pressure increase control is performed. After the execution, the second catalyst warm-up control is executed. Thereby, during execution of the second catalyst warm-up control, it is possible to effectively achieve both the promotion of the catalyst warm-up and the elimination of the shortage of the braking force of the vehicle.

  In addition, this invention is not limited to the said embodiment, A various modification can be employ | adopted within the scope of the present invention. For example, in the above embodiment, during the negative pressure increase control, the second ignition timing is equal to the normal ignition timing θ0 (therefore, the second throttle valve opening is equal to the normal throttle valve opening TA0). Although the second ignition timing is set to a timing that is more advanced than the first ignition timing (θ0 + θA) and later than the normal ignition timing θ0 (thus, the second throttle valve opening is It may be set smaller than the first throttle valve opening (TA + TAA) and larger than the normal throttle valve opening TA0.

  In the above embodiment, the higher the coolant temperature Tw and the higher the engine speed NE, the more the ignition timing θ during the second catalyst warm-up control becomes more retarded (accordingly, the second catalyst warm-up). The throttle valve opening TA during the control is set to a larger value), but the ignition timing θ (accordingly, the throttle valve opening TA) during the second catalyst warm-up control is set based on the coolant temperature Tw and the engine speed NE. It may be constant regardless of one or both of the above.

  In addition, in the above embodiment, the retard amount θdelay added to the normal ignition timing θ0 is obtained from the temporary retard amount θA and the retard return amount θadv (θdelay = θA−θadv). The amount θdelay may be obtained directly.

  In the above embodiment, the ignition timing θ during the second catalyst warm-up control is obtained from the normal ignition timing θ0, the provisional retard amount θA, and the retard return amount θadv (feed forward control). The ignition timing θ during the second catalyst warm-up control is based on the throttle valve downstream pressure Pm estimated or detected so that the throttle valve downstream pressure Pm matches the value Pref (or a reference pressure equal to or lower than Pref). Thus, the ignition timing θ (accordingly, the throttle valve opening TA) may be feedback controlled.

  In this case, the routine shown by the flowchart in FIG. 11 is used instead of the routine shown in FIG. The routine in FIG. 11 is obtained by replacing steps 730, 732, and 734 with steps 1105 and 1110 in the routine shown in FIG. In this case, specifically, when the estimated or detected throttle valve downstream pressure Pm is higher than the value Pref, the ignition timing θ is adjusted to the advance side from the current ignition timing, and the throttle valve opening TA is The opening is adjusted to be smaller than the current opening. On the other hand, when the estimated or detected throttle valve downstream pressure Pm is lower than the value Pref, the ignition timing θ is adjusted to be retarded from the current ignition timing, and the throttle valve opening TA is larger than the current opening. It is adjusted to the opening.

  Thereby, the throttle valve downstream pressure Pm can be directly and reliably adjusted to the value Pref during the second catalyst warm-up control. Therefore, even if the brake operation is performed relatively frequently during the traveling of the vehicle under the second catalyst warm-up control, the above-described “replenishment of negative pressure” can be reliably performed, and the occurrence of the above-described insufficient braking force can be ensured. Can be suppressed.

1 is a schematic configuration diagram of a system in which a control device for an internal combustion engine according to an embodiment of the present invention is applied to a spark ignition type multi-cylinder internal combustion engine. 3 is a flowchart showing a program executed by a CPU shown in FIG. 1 for performing catalyst warm-up determination. 3 is a flowchart showing a program executed by the CPU shown in FIG. 1 for determining movement. It is the flowchart which showed the program for the idle execution determination which is a program which CPU shown in FIG. 1 performs. 3 is a flowchart showing a program executed by the CPU shown in FIG. 1 for performing a negative pressure increase determination. 3 is a flowchart showing a program executed by the CPU shown in FIG. 1 for performing negative pressure holding determination. It is the flowchart which showed the program for performing ignition timing control which is the program which CPU shown in FIG. 1 performs. 3 is a flowchart showing a program executed by the CPU shown in FIG. 1 for performing throttle valve opening control. 2 is a time chart showing an example when the ignition timing and the throttle valve opening are controlled by the control device shown in FIG. 1 when there is a catalyst warm-up request. 10 is a time chart corresponding to FIG. 9 when there is a period in which the accelerator pedal is operated in the middle. It is the flowchart which showed the program for CPU which the CPU of the control apparatus of the internal combustion engine which concerns on the modification of embodiment of this invention performs, and performs ignition timing control.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 21 ... Cylinder, 22 ... Piston, 24 ... Crankshaft, 25 ... Combustion chamber, 30 ... Cylinder head part, 37 ... Spark plug, 38 ... Igniter, 39 ... Injector, 41 ... Intake manifold, 42 ... Surge Tank, 43 ... Intake duct, 45 ... Throttle valve, 45a ... Throttle valve actuator, 52 ... Exhaust pipe, 53 ... First catalyst, 54 ... Second catalyst, 60 ... Negative pressure accumulator, 61 ... Bypass passage, 61a ... Upstream 61b ... downstream part, 61c ... central part, 61c1 ... throttling part, 62 ... bypass flow control valve, 63 ... main passage for negative pressure introduction, 64 ... sub passage for negative pressure introduction, 65 ... brake booster, 71 ... throttle Position sensor, 72 ... Crank position sensor, 73 ... Cooling water temperature sensor, 76 ... Accelerator opening sensor, 7 ... the vehicle speed sensor

Claims (9)

Throttle valve drive means for driving a throttle valve disposed in an intake passage of an internal combustion engine mounted on the vehicle in response to a predetermined drive instruction signal;
Brake boosting means for increasing the braking force of the vehicle by increasing the brake operating force by utilizing the throttle valve downstream pressure that is lower than the atmospheric pressure generated downstream of the throttle valve in the intake passage. When,
Ignition means for igniting an air-fuel mixture supplied to the combustion chamber of the internal combustion engine in response to a predetermined ignition instruction signal;
An exhaust gas purifying catalyst disposed in an exhaust passage of the internal combustion engine;
A warm-up request determining means for determining the presence or absence of a catalyst warm-up request for promoting the warm-up of the catalyst;
An increase request determination means for determining whether or not there is a negative pressure increase request for decreasing the throttle valve downstream pressure when it is determined that there is a catalyst warm-up request;
When it is determined that there is no catalyst warm-up request, the ignition instruction signal is transmitted to the ignition means, so that the ignition timing by the ignition means is determined based on the operating state of the internal combustion engine. The normal opening timing is controlled so that the opening degree of the throttle valve is determined based on the operating state of the internal combustion engine by transmitting the drive instruction signal to the throttle valve driving means. Normal control means for controlling the throttle valve opening;
When it is determined that there is a request for warming up the catalyst and there is no request for increasing the negative pressure, the ignition timing signal is transmitted to the ignition means so that the ignition timing is retarded from the normal ignition timing. Is controlled to the first ignition timing, and the throttle valve opening is larger than the normal throttle valve opening by transmitting the drive instruction signal to the throttle valve driving means. First catalyst warm-up control means for controlling the first throttle valve opening;
When it is determined that there is a request for increasing the negative pressure during the execution of the control by the first catalyst warm-up control unit, the ignition timing signal is transmitted to the ignition unit to thereby change the ignition timing to the first ignition timing. Is controlled to a second ignition timing that is a more advanced timing, and the drive instruction signal is transmitted to the throttle valve drive means, so that the opening of the throttle valve is made greater than the first throttle valve opening. Negative pressure increase control means for controlling the second throttle valve opening to be a small opening;
An internal combustion engine control device comprising:
When it is determined that the predetermined condition is satisfied during the execution of the control by the negative pressure increase control means, the control by the negative pressure increase control means is stopped, the downstream pressure of the throttle valve is determined by the opening degree of the throttle valve The pressure is higher than the pressure corresponding to the case where the second throttle valve opening is maintained and is lower than the pressure corresponding to the case where the opening of the throttle valve is maintained at the first throttle valve opening. A third ignition that is a timing between the first ignition timing and the second ignition timing by transmitting the ignition instruction signal to the ignition means so as to be maintained below a predetermined pressure. And controlling the timing to transmit the drive instruction signal to the throttle valve driving means, thereby controlling the opening of the throttle valve to the first throttle valve opening and the second throttle valve opening. Control apparatus for an internal combustion engine equipped with a second catalyst warm-up control means for controlling the third throttle valve opening which is the opening between. A control device for an internal combustion engine according to claim 1,
A load device mounted on the vehicle and driven by the power of the internal combustion engine;
The load device is prohibited from being driven by the internal combustion engine during control execution by the negative pressure increase control means, and is allowed to be driven by the internal combustion engine during control execution by the second catalyst warm-up control means. A control apparatus for an internal combustion engine configured as described above. A control device for an internal combustion engine according to claim 1 or 2,
Operating speed acquisition means for acquiring the operating speed of the internal combustion engine;
Cooling water temperature acquisition means for acquiring the temperature of cooling water for cooling the internal combustion engine;
With
The second catalyst warm-up control means includes:
A control device for an internal combustion engine configured to determine the third ignition timing based on one or both of the operation speed and the coolant temperature. A control device for an internal combustion engine according to claim 1 or 2,
Pressure acquisition means for acquiring the throttle valve downstream pressure;
The second catalyst warm-up control means includes:
The third ignition timing is feedback-controlled based on the acquired throttle valve downstream pressure so that the acquired throttle valve downstream pressure is within the range and matches a reference pressure equal to or lower than the predetermined pressure. Control device for an internal combustion engine. The control apparatus for an internal combustion engine according to claim 1 or 2,
The second catalyst warm-up control means includes:
A control device for an internal combustion engine configured to determine the third ignition timing so that the third ignition timing is not advanced from the normal ignition timing. A control device for an internal combustion engine according to claim 1 or 2,
Comprising idling determination means for determining whether or not the internal combustion engine is idling;
The second catalyst warm-up control means includes:
When the internal combustion engine is not in an idling state during the execution of the control by the second catalyst warm-up control means, the third ignition timing is set equal to the first ignition timing, or advanced from the first ignition timing. The control apparatus for an internal combustion engine configured to set a timing that is retarded from the third ignition timing when the internal combustion engine is in an idling state. The control apparatus for an internal combustion engine according to any one of claims 1 to 6,
The second catalyst warm-up control means includes:
As the predetermined condition, from the start of control execution by the negative pressure increase control means, the pressure inside the negative pressure chamber that stores air having a pressure lower than the atmospheric pressure of the brake boosting means appropriately increases the braking force. A control device for an internal combustion engine configured to use that the time required to decrease to a possible extent has elapsed. A control device for an internal combustion engine according to any one of claims 1 to 7,
Starting determination means for determining whether or not the vehicle has started,
The control apparatus for an internal combustion engine configured to determine that the negative pressure increase request is present when the increase request determination means determines that the vehicle has started. The control device for an internal combustion engine according to any one of claims 8 to 10,
Comprising stop determining means for determining whether or not the vehicle has stopped;
The first catalyst warm-up control means includes
When it is determined that the vehicle has stopped during the execution of the control by the second catalyst warm-up control means, the second catalyst warm-up control is stopped, the ignition timing is controlled to the first ignition timing, and the A control apparatus for an internal combustion engine configured to control an opening of a throttle valve to the first throttle valve opening.

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