JP2007255392A - Engine control device and engine control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain high exhaust emission purification performance for a long period of time by a catalyst device according to the traveling state of a vehicle when the traveling state of the vehicle in the future can be predicted beforehand. <P>SOLUTION: In this engine control device 11, a start catalyst (SC) state estimating part 41 estimates the changed amount of vehicle speed based on the information on the prediction of a vehicle state acquired by an information acquiring part 40. Based on the changed amount of the vehicle speed, a catalyst oxygen storage amount OSA control part 42 so controls the OSA of the SC that the changed amount of OSA can be changed beforehand by anticipating the amount of the OSA to be changed. Therefore, the OSA can be accurately controlled according to the state of the vehicle in the future. Since the SC can store an optimum amount of oxygen, the emission purification performance of the catalyst can be effectively utilized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine control apparatus and an engine control method, and more particularly to an engine control apparatus and an engine for controlling an engine in a vehicle including an engine that sucks an air-fuel mixture and a catalytic converter that purifies exhaust gas discharged from the engine with a catalyst. It relates to a control method.

  One measure for preventing global warming due to air pollution in recent years is to reduce harmful components in exhaust gas discharged from vehicle engines. The exhaust gas burned by the engine contains various harmful components, the main ones being CO (carbon monoxide) generated during incomplete combustion of gasoline and during deceleration. HC (hydrocarbon) discharged without burning due to misfire or incomplete combustion due to an over-rich mixture such as NOx (nitrogen oxide) generated when nitrogen in the air combines with oxygen when the combustion temperature is high It is.

  In order to reduce such harmful components, the air-fuel ratio, which is the ratio of air to fuel supplied to the engine, is calculated from the stoichiometric air-fuel ratio, that is, the theoretically required air amount and fuel amount for the fuel to burn completely. For example, air-fuel ratio control for controlling the intake air amount or the fuel amount based on the amount of oxygen contained in the exhaust gas is performed. However, the fuel of the air-fuel mixture is controlled so that the air-fuel ratio becomes the stoichiometric air-fuel ratio in the case of a normal load. In order to increase the engine output at a high load, it is preferable to set the engine to a rich state in which the amount of fuel in the air-fuel mixture is increased. For this reason, harmful exhaust gas is discharged depending on the running state of the vehicle, and it is the catalyst device that purifies such exhaust gas.

  Even in the catalyst device, in order to maximize the purification capability, the chemical reaction cannot be performed normally unless the air-fuel ratio of the air-fuel mixture is the stoichiometric air-fuel ratio. Therefore, for example, when the air-fuel ratio continues from the stoichiometric air-fuel ratio to the rich side or the lean side for a predetermined time, the purification capacity of the catalyst device is maintained to the maximum by changing the air-fuel ratio to the lean side or the rich side. (For example, refer to Patent Document 1).

By the way, in the catalyst device, in order to absorb such fluctuation of the air-fuel ratio, a catalyst having excellent oxygen storage / release capability is used. Such a catalyst absorbs excess oxygen by an oxidation reaction in a combustion state in an oxygen-excess atmosphere, and releases oxygen by a reduction reaction in a reduction atmosphere. The amount of oxygen adsorbed by the catalyst is called the catalyst oxygen storage amount (OSA). In order to maintain the purification capacity of the catalytic device, it is necessary to balance the oxidation reaction with respect to CO and HC in the exhaust gas and the reduction reaction with respect to NOx. For this purpose, OSA must be kept at an appropriate value. Don't be. That is, when the vehicle is in a certain running state and the OSA is in the vicinity of the maximum catalyst oxygen storage amount or the minimum catalyst oxygen storage amount, the oxidation-reduction reaction performed when the air-fuel ratio shifts to the rich state or the lean state. However, in order to cope with fluctuations in the air-fuel ratio, it is preferable that the OSA be kept at a value that is half the maximum oxygen storage amount of the catalyst.
JP 2005-344621 A

  However, for example, when the lean or rich state of the air-fuel mixture is continued for a long period of time, such as when the vehicle travels on a long slope, the OSA continuously increases or decreases during that period. If the catalyst is controlled to be half of the maximum oxygen storage amount, the allowable range in which oxygen can be stored or released from the point of transition to the lean or rich state is limited to half of the maximum catalyst oxygen storage amount. Thereafter, the catalyst device has a problem that the exhaust gas purification ability cannot be sufficiently exhibited.

  The present invention has been made in view of such points, and when the traveling state of a vehicle in the future can be estimated in advance, the high purification ability of exhaust gas by the catalyst device is maintained for a long time according to the traveling state. An object of the present invention is to provide an engine control device and an engine control method.

  In the present invention, in order to solve the above problems, in an engine control apparatus that controls an engine in a vehicle including an engine that sucks an air-fuel mixture and a catalytic converter that purifies exhaust gas exhausted from the engine with a catalyst. Information acquisition means for acquiring vehicle state prediction information for predicting the state of the vehicle on a route that the vehicle will pass in the future, and based on the vehicle state prediction information, the vehicle speed change amount in the route is estimated, and the vehicle speed change amount Based on the estimated catalytic oxygen storage amount, the catalytic converter state estimating means for estimating the state of the catalytic converter by calculating the estimated catalytic oxygen storage amount of the catalytic converter at the predetermined point based on the estimated catalytic oxygen storage amount. The target catalytic oxygen storage amount of the catalytic converter targeted at the point of The engine control apparatus characterized by medium oxygen storage amount is and a catalytic oxygen storage amount control means for controlling so that the target catalyst oxygen storage amount is provided.

  Further, according to the present invention, in an engine control method for controlling the engine in a vehicle equipped with an engine that sucks an air-fuel mixture and a catalytic converter that purifies exhaust gas exhausted from the engine with a catalyst, information is acquired by a computer. Means for obtaining vehicle state prediction information for predicting the state of the vehicle on a route through which the vehicle will pass in the future, and catalytic converter state estimating means for calculating the vehicle speed change amount on the route based on the vehicle state prediction information; Estimating the state of the catalytic converter by calculating the estimated catalytic oxygen storage amount of the catalytic converter at a predetermined point based on the vehicle speed change amount, and the catalytic oxygen storage amount control means includes the estimation Based on the amount of oxygen stored in the catalyst, the target catalytic converter is targeted at a point before the predetermined point. An engine control method is provided in which a process of setting a catalyst oxygen storage amount and controlling the current catalyst oxygen storage amount of the catalytic converter to be the target catalyst oxygen storage amount is performed. The

  According to such an engine control device and an engine control method, the catalytic converter state estimating means estimates the vehicle speed change amount based on the vehicle state prediction information acquired by the information acquisition means, and based on the vehicle speed change amount, the catalyst oxygen storage is performed. The amount control means controls the catalyst oxygen storage amount of the catalytic converter to change in advance in anticipation of the change amount of the catalyst oxygen storage amount that will change. Will be able to control.

  In the engine control device and the engine control method of the present invention, the catalytic converter state estimation unit estimates the vehicle speed change amount based on the vehicle state prediction information acquired by the information acquisition unit, and the catalyst oxygen storage amount control is performed based on the vehicle speed change amount. Since the means controls the catalyst oxygen storage amount of the catalytic converter to change in advance in anticipation of the change amount of the catalyst oxygen storage amount that will change, the catalyst oxygen storage amount is accurately controlled according to the future vehicle conditions. become able to. As a result, the catalytic converter can store an optimal amount of oxygen, and the exhaust gas purification ability of the catalyst can be effectively utilized.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the system configuration of an engine control system that controls the engine will be described.
FIG. 1 is a block diagram showing the system configuration of the engine control system.

  The engine control system includes an engine 10 and an engine control device 11 that controls the engine 10. The engine 10 is provided with an intake passage 12 for sucking a mixture of air and fuel and an exhaust passage 13 for discharging exhaust gas combusting the mixture. A start catalyst is placed in the middle of the exhaust passage 13. (SC) 14 and underfloor type catalyst (UF) 15 are installed.

  These SC14 and UF15 are catalytic converters that purify the exhaust gas with a catalyst. The SC14 having a large capacity mainly purifies the exhaust gas, and the UF15 having a small capacity purifies the exhaust gas that could not be completely purified there. It is configured to do.

  A first air-fuel ratio sensor 16 that detects the air-fuel ratio of the exhaust gas discharged from the engine 10 is provided in the exhaust passage 13 upstream of the SC 14, and the purified exhaust gas is provided in the downstream exhaust passage 13. A second air-fuel ratio sensor 17 for detecting the air-fuel ratio of the engine is provided, and a temperature sensor 18 for detecting the catalyst bed temperature is provided for the SC 14. Each output is connected to the engine control device 11. Yes. Thereby, the engine control device 11 can know the oxygen concentration of the exhaust gas entering the SC 14 by the first air-fuel ratio sensor 16, and know the oxygen concentration of the exhaust gas leaving the SC 14 by the second air-fuel ratio sensor 17. The temperature sensor 18 can know the coefficient at which the catalyst can store oxygen to the maximum according to the catalyst bed temperature of the SC 14.

  An air flow sensor 19 and an injector 20 are provided in the intake passage 12 on the intake side of the engine 10, and are connected to the engine control device 11. The air flow sensor 19 detects the amount of air taken into the engine 10. Based on this air amount, the engine control device 11 controls the amount of fuel injected into the intake passage 12 by the injector 20 to control the air-fuel ratio of the air-fuel mixture. An air injector 21 controlled by the engine control device 11 is provided in the exhaust passage 13 between the engine 10 and the SC 14. The air injector 21 feeds air whose injection amount is controlled into the exhaust gas discharged from the engine 10. Furthermore, the engine control device 11 inputs vehicle state prediction information for predicting the future state of the vehicle. The vehicle state prediction information includes information on curves obtained from the navigation system, map information such as downhill or uphill slope angle information, traffic congestion obtained from road traffic information communication systems, traffic regulations, traffic lights, etc. It includes the speed information of the preceding vehicle obtained from the communication system.

  According to such an engine control system, the engine control device 11 can detect the air-fuel ratio of the exhaust gas entering the SC 14 detected by the first air-fuel ratio sensor 16 and the SC 14 detected by the second air-fuel ratio sensor 17. The OSA adsorbed by the SC 14 is grasped by comparing the air-fuel ratio of the exhaust gas that has come out. The engine control device 11 estimates how the air-fuel ratio changes due to changes in the vehicle speed and torque from the vehicle state prediction information, and how the OSA of the SC 14 also changes. By controlling the air-fuel ratio of the air-fuel mixture in advance by controlling 20, the OSA of the SC 14 after the vehicle speed and torque have changed can be controlled. For example, the engine control device 11 can control the maximum oxygen storage amount of the catalyst in the OS 14 of the SC 14 after the vehicle speed and torque are changed. For example, the control may be performed so as to be approximately half of the maximum oxygen storage amount of the catalyst.

Next, the hardware configuration of the engine control device 11 will be described.
FIG. 2 is a block diagram showing a hardware configuration of the engine control apparatus.
The engine control device 11 includes a microcomputer 30, which is connected to a bus 31 in the engine control device 11 and is connected to an external network such as an in-vehicle network via an I / F (Interface) 32. The signal line 33 is connected.

  The microcomputer 30 has a CPU (Central Processing Unit) 34, and a ROM (Read Only Memory) 35 and a RAM 36 are connected to the CPU 34 via a bus 37 in the microcomputer 30. The CPU 34 is connected to the bus 31 of the engine control device 11 via the bus 37.

  The CPU 34 controls the entire engine control device 11. The RAM 36 temporarily stores at least part of an OS (Operating System) program and application programs executed by the CPU 34. The RAM 36 stores various data necessary for the processing of the CPU 34. The ROM 35 stores OS programs, application programs, and the like.

  The application program includes a program for a start catalyst state estimation process (SC state estimation process) and a catalyst oxygen storage amount control process (OSA control process) executed by the engine control device 11.

Next, a functional configuration of the engine control device 11 realized by the hardware configuration of FIG. 2 will be described.
FIG. 3 is a block diagram showing a functional configuration of the engine control apparatus.

The engine control device 11 includes an information acquisition unit 40, a start catalyst state estimation unit (SC state estimation unit) 41, and a catalyst oxygen storage amount control unit (OSA control unit).
The information acquisition unit 40 acquires vehicle state prediction information such as vehicle position and route information using a navigation system or the like.

  The SC state estimation unit 41 predicts a vehicle speed change amount indicating how the vehicle speed changes based on the vehicle state prediction information, and determines which OSA is used when the vehicle travels with the vehicle speed and torque changed as predicted. How it changes. Further, the SC state estimation unit 41 estimates the future OSA of the SC 14 from the air-fuel ratio of the exhaust gas detected by the first air-fuel ratio sensor 16 and the second air-fuel ratio sensor 17, and the SC 14 detected by the temperature sensor 18. The maximum OSA that can be occluded by the SC 14 is estimated from the catalyst bed temperature.

  The OSA control unit 42 controls the vehicle speed and torque by controlling the fuel amount in advance by the injector 20 or by controlling the oxygen amount of the exhaust gas in advance by the air injector 21 based on the estimation result of the SC state estimation unit 41. Controls the OSA of the SC 14 after the change. For example, the OSA control unit 42 performs control so that the OSA of the SC 14 after the vehicle speed and torque are changed is approximately half of the maximum oxygen storage amount of the catalyst.

  Specifically, the SC state estimation unit 41 and the OSA control unit 42 calculate an estimated OSA representing how the OSA will change as a result of changes in vehicle speed and torque in the future, as shown below. Then, a target OSA indicating a target value when the current OSA is changed in advance according to the estimated OSA is set, and the OSA of the SC 14 is controlled so that the current OSA becomes the target OSA.

Next, an outline of OSA control by the engine control device 11 will be described.
4A and 4B are diagrams showing a change in torque and a change in OSA, where FIG. 4A shows a change in torque when the predicted vehicle speed changes, FIG. 4B shows a change in estimated OSA at a planned travel point, and FIG. Indicates a change in the target OSA of the planned travel point.

  First, in FIG. 4A, it is assumed that the vehicle is currently traveling on a flat ground and travels on an uphill road from a planned traveling point A to point B. In this case, as shown in FIG. 4A, there is no change in vehicle speed and no change in torque from the local point to the point A. Since the vehicle speed decreases from A point to B point at the start of climbing, the torque is increased.

  In such a situation, as shown in FIG. 4B, the OSA of the SC 14 maintains a predetermined value from the local point to the A point, and increases the torque on the uphill road from the A point to the B point. In this case, the exhaust gas exhausted from the engine 10 also becomes rich and becomes in an oxygen-deficient state, so that the OSA in SC14 decreases and the vehicle When reaching point B, OSA will drop by ΔOSA. For this reason, at the point B, due to the decrease in OSA, the air-fuel ratio of the air-fuel mixture in SC 14 becomes richer than the stoichiometric air-fuel ratio, the oxidation reaction of harmful components hardly occurs, and the purification ability by the catalyst is reduced. .

  On the other hand, in the present invention, if it is known in advance that the OSA of the SC 14 decreases at the point B, as shown in FIG. 4C, the OSA control unit 42 precedes at the local point stage. Then, the target OSA is set so as to increase the OSA at the point A, which is the elapsed point before the point B, and the air-fuel mixture is controlled to be in a rich state so as to become the target OSA. The purification capacity of the SC 14 is not reduced so as not to drop significantly. The point A may be a point where the torque is switched to a high load, for example, a starting point of an uphill slope, or a point separated from the point B by a predetermined distance. Further, the point B may be an end point of an uphill slope or a point where the estimated OSA is minimized.

Next, processing for estimating the state of the SC 14 by the SC state estimating unit 41 will be described.
FIG. 5 is a flowchart showing SC state estimation processing, FIG. 6 is a diagram showing changes in vehicle speed corresponding to the curve radius of the vehicle, FIG. 7 is a diagram showing changes in air-fuel ratio corresponding to changes in vehicle speed, and FIG. FIG. 9 is a diagram showing a change in the corresponding air-fuel ratio, and FIG. 9 is a diagram showing a change in the catalyst bed temperature corresponding to a change in torque.

The SC state estimation unit 41 repeatedly executes processing according to the following steps by the SC state estimation processing program.
[Step S11] The CPU 34 acquires vehicle state prediction information for estimating a change in vehicle speed and a change in torque. The vehicle state prediction information is vehicle position and route information acquired using car navigation or the like. For example, the CPU 34 acquires a curve radius, a slope angle, and the like in a route of a certain section where the vehicle will pass in the future.

[Step S12] The CPU 34 estimates the amount of change in vehicle speed according to the curve radius, slope angle, etc. acquired in the process of step S11.
Here, as shown in FIG. 6, the vehicle has to be decelerated when the curve radius decreases, so the CPU 34 refers to the ROM 35 storing the data of the characteristic, and determines the vehicle speed corresponding to the curve radius. The vehicle speed change amount is calculated from the difference between the acquired future vehicle speed and the current vehicle speed. The current vehicle speed is obtained from an electronic control unit that controls the engine.

  Although not shown in the figure, since the vehicle decelerates when the upward slope angle increases, the torque is increased to compensate for the change in the vehicle speed, and the acceleration increases when the downward slope angle increases, so the torque is increased to compensate for the change in the vehicle speed. Therefore, the CPU 34 refers to the ROM 35 storing the characteristic data, and acquires the future vehicle speed change amount corresponding to the slope angle.

[Step S13] The CPU 34 calculates the future change amount of the air-fuel ratio of the air-fuel mixture in accordance with the future change amount of the vehicle speed calculated in the process of step S12.
Here, as shown in FIG. 7, when accelerating, the air-fuel ratio of the air-fuel mixture decreases to become a rich state, and when decelerating, the air-fuel ratio of the air-fuel mixture increases to become a lean state. Refers to the ROM 35 storing the characteristic data, obtains the air-fuel ratio of the air-fuel mixture corresponding to the amount of change in the vehicle speed due to future acceleration / deceleration, The amount of change in the air / fuel ratio of the air / fuel mixture in the future is calculated from the difference from the air / fuel ratio of the current air / fuel mixture detected by the air / fuel ratio sensor 16.

  In the above description, the change amount of the vehicle speed is estimated from the curve radius or the slope angle, and the change amount of the air-fuel ratio of the air-fuel mixture in the future is acquired from the change amount of the vehicle speed, as shown in FIG. Since there is a correlation between the slope angle and the air-fuel ratio so that the air-fuel mixture becomes rich in the uphill direction, the air-fuel mixture is in the rich state, and conversely in the downhill direction, the lean state is established. The air-fuel ratio of the future air-fuel mixture may be acquired directly from the slope angle.

[Step S14] The CPU 34 calculates a future change amount of OSA (ΔOSA) according to the future change amount of the air-fuel ratio of the air-fuel mixture calculated in the process of step S13. That is, assuming that the amount of change in the air-fuel ratio of the air-fuel mixture in the future is ΔA / F and the catalyst adsorption oxygen coefficient is K, ΔOSA is
ΔOSA = ■ ΔA / F × K
Is calculated by For example, as shown in FIG. 4B, ΔOSA of OSA that will change between point A and point B is calculated.

  [Step S15] The CPU 34 calculates an estimated OSA indicating a future OSA. That is, from the air-fuel ratio of the exhaust gas entering the SC 14 detected by the first air-fuel ratio sensor 16 and the air-fuel ratio of the exhaust gas exiting from the SC 14 detected by the second air-fuel ratio sensor 17, the current OSA is The estimated OSA is calculated by adding / subtracting ΔOSA calculated in step S14 to the current OSA.

[Step S16] The CPU 34 estimates the torque required to realize the future vehicle speed according to the future vehicle speed change amount calculated in the process of Step S12.
[Step S17] The CPU 34 acquires a change amount of the catalyst bed temperature indicating how far the catalyst bed temperature of the SC 14 will change in the future in response to the increase or decrease of the torque estimated in the process of Step S16.

  Here, as shown in FIG. 9, when the torque increases, the air-fuel ratio state of the air-fuel mixture becomes rich, and the air-fuel mixture in the rich state is combusted and the catalyst bed temperature also rises. The amount of change in the catalyst bed temperature corresponding to the future torque is acquired by referring to the ROM 35 storing the data.

  [Step S18] The CPU 34 calculates the future catalyst bed temperature. That is, the future catalyst bed temperature is calculated by adding or subtracting the amount of change in the future catalyst bed temperature acquired in step S17 to the current catalyst bed temperature detected by the temperature sensor 18.

  [Step S19] The CPU 34 calculates a catalyst maximum oxygen storage amount (Cmax), which is the maximum OSA in the future, according to the future catalyst bed temperature calculated in the process of step S18. That is, based on the current catalyst bed temperature detected by the temperature sensor 18, Cmax that can be stored by the SC 14 at that temperature is calculated, and a coefficient that changes corresponding to the future catalyst bed temperature is calculated as the Cmax. Multiply and calculate future Cmax. Since the Cmax that can be stored in the SC 14 increases as the catalyst bed temperature increases, the SC 14 is more likely to store oxygen as the temperature increases.

  By the above processing, it is estimated how the vehicle speed and torque change from the vehicle state prediction information using car navigation etc., and the estimated OSA that the SC 14 should have occluded at the end of the vehicle speed change according to this estimation result. Is calculated. Further, a torque corresponding to the vehicle speed change amount is estimated, and how the catalyst bed temperature will change in the future is calculated according to this torque, and Cmax corresponding to the catalyst bed temperature at the time of change is calculated. .

Finally, processing for controlling OSA by the OSA control unit 42 will be described.
FIG. 10 is a flowchart showing the OSA control process, and FIG. 11 is a diagram showing the relationship between ΔOSA and the target OSA.

The OSA control unit 42 executes processing according to the following steps by the OSA control processing program after the SC state estimation processing.
[Step S21] The CPU 34 determines whether or not the estimated OSA is smaller than a predetermined value A1 that is a lower limit value of the OSA fluctuation allowable range. If the estimated OSA is smaller than the predetermined value A1, the process proceeds to step S22, and if larger, the process proceeds to step S23.

  [Step S22] When the estimated OSA is smaller than the predetermined value A1, the CPU 34 estimates that the OSA is below the allowable fluctuation range, and therefore sets the target OSA at the start of the speed change to be larger than Cmax / 2. For example, since it is estimated that the OSA decreases at the point B in FIG. 4B, the CPU 34 sets the target OSA at the point A in FIG. 4C larger than Cmax / 2.

  Here, as shown in FIG. 11, when the estimated OSA decreases by ΔOSA, the OSA control unit 42 controls to increase the target OSA at the start of speed change, but the target OSA corresponding to ΔOSA at that time is controlled. The CPU 34 obtains data from the ROM 35 that stores data representing the relationship between ΔOSA and the target OSA. For example, when the CPU 34 estimates that the OSA decreases by ΔOSA at the point B in FIG. 4B, the CPU 34 sets the target OSA for increasing the OSA until reaching the point A at the start of the speed change by ΔOSA. And the target OSA.

  [Step S23] The CPU 34 determines whether or not the estimated OSA is larger than a predetermined value A2 that is an upper limit value of the OSA fluctuation allowable range. If the estimated OSA is larger than the predetermined value A2, the process proceeds to step S24, and if smaller, the process proceeds to step S25.

[Step S24] Since the increase in OSA is estimated when the estimated OSA is larger than the predetermined value A2, the CPU 34 sets the target OSA smaller than Cmax / 2.
[Step S25] When the estimated OSA is within the OSA fluctuation allowable range, the CPU 34 sets the target OSA to Cmax / 2 because it is not necessary to change the OSA in advance.

  [Step S26] The CPU 34 controls the air-fuel ratio of the air-fuel mixture sucked into the engine 10 to control the air-fuel ratio of the exhaust gas by controlling the injector 20 so that the current OSA becomes the target OSA. To do. Alternatively, the air fuel ratio of the exhaust gas in the exhaust passage 13 is controlled by controlling the air injector 21. In this way, the OSA of the SC 14 is controlled by controlling the air-fuel ratio of the exhaust gas.

  For example, when it is known in advance that the stratified operation that can improve fuel efficiency with less fuel in the air-fuel mixture can be performed for a long time or fuel cut is frequently performed by the above processing, the current OSA The air-fuel ratio of the air-fuel mixture is controlled so as to reduce the amount in advance. Also, for example, when it is known in advance that the torque needs to be increased due to road topographical factors, the air-fuel ratio of the air-fuel mixture is increased so as to increase the OSA in advance in order to cope with the shortage of OSA caused by it. Be controlled. As a result, the OSA is optimally controlled to a value that is half of the maximum catalyst oxygen storage amount that the SC 14 always wants to keep, so that the purification capacity of the SC 14 can be increased.

  Further, the engine control device 11 performs control according to the OSA control, and controls the air-fuel ratio of the air-fuel mixture in advance so that the OSA becomes a predetermined target OSA even if the rich state or the lean state is performed for a long time. As a result, the actual air-fuel ratio is less likely to deviate from the stoichiometric air-fuel ratio, so that the SC 14 can be maintained in a state with a large purification capacity, and the capacity of the SC 14 can be reduced by the increase in the purification capacity. It becomes possible.

  In the above embodiment, the vehicle state prediction information is acquired using the navigation system. However, a certain section in which the vehicle will pass through the vehicle-to-vehicle communication system that can communicate with each other between the vehicles. You may make it acquire the average vehicle speed of the other vehicle in the past predetermined period in this route. At this time, it is estimated that the vehicle speed of the own vehicle will approach the vehicle speed of the other vehicle in the future, and the future vehicle speed change amount can be calculated from the difference between the current vehicle speed of the own vehicle and the vehicle speed of the other vehicle. For example, if it is predicted that the route that will travel from the speed of another vehicle will be congested in the future, or if the host vehicle is predicted to stop in the future due to traffic lights etc., the vehicle may shift from the current state to the deceleration state. A future vehicle speed change amount can be calculated from the difference between the predicted and the vehicle speed before and after the transition. In addition, when it is predicted that the vehicle will depart from the stop state by the traffic light, the vehicle is predicted to shift from the stop state to the acceleration state, and the future vehicle speed change amount is calculated from the difference between the vehicle speed before and after the transition. be able to. A future change amount of the air-fuel ratio of the air-fuel mixture may be calculated according to these vehicle speed change amounts, and a future ΔOSA may be calculated according to the change amount of the air-fuel ratio of the air-fuel mixture. Here, when ΔOSA actually calculated in a predetermined situation is accumulated a predetermined number of times, the difference between the average value of those ΔOSA and ΔOSA calculated this time is a fixed ratio with respect to ΔOSA calculated this time You may make it reflect.

It is a block diagram showing a system configuration of an engine control system. It is a block diagram which shows the hardware constitutions of an engine control apparatus. It is a block diagram which shows the function structure of an engine control apparatus. It is a figure which shows the change of a torque, and a change of OSA, Comprising: (A) shows the torque change at the time of the estimated vehicle speed change, (B) shows the change of estimated OSA of a driving plan point, (C) is a driving plan. The change of the target OSA of the point is shown. It is a flowchart which shows SC state estimation processing. It is a figure which shows the change of the vehicle speed corresponding to the curve radius of a vehicle. It is a figure which shows the change of the air fuel ratio corresponding to a vehicle speed change. It is a figure which shows the change of the air fuel ratio corresponding to a slope angle. It is a figure which shows the change of the catalyst bed temperature corresponding to the change of a torque. It is a flowchart which shows OSA control processing. It is a figure which shows the relationship between (DELTA) OSA and target OSA.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Engine control apparatus 40 Information acquisition part 41 SC state estimation part 42 OSA control part

Claims (5)

In an engine control device that controls an engine in a vehicle including an engine that sucks an air-fuel mixture and a catalytic converter that purifies exhaust gas exhausted from the engine with a catalyst.
Information acquisition means for acquiring vehicle state prediction information for predicting the state of the vehicle in a route through which the vehicle will pass in the future;
Based on the vehicle state prediction information, the vehicle speed change amount in the route is estimated, and based on the vehicle speed change amount, the estimated catalytic oxygen storage amount of the catalytic converter at a predetermined point is calculated, thereby determining the state of the catalytic converter. Catalytic converter state estimating means for estimating;
Based on the estimated catalyst oxygen storage amount, a target catalyst oxygen storage amount of the catalytic converter targeted at a point before the predetermined point is set, and the current catalyst oxygen storage amount of the catalytic converter is the target catalyst oxygen storage amount. Catalyst oxygen storage amount control means for controlling to become,
An engine control device comprising:   The catalytic converter state estimating means estimates a torque required in the future to realize the vehicle speed change amount, calculates a catalyst bed temperature of the catalytic converter at the predetermined point based on the torque, and the catalyst bed 2. The engine control apparatus according to claim 1, wherein a maximum value of the estimated catalyst oxygen storage amount is calculated based on a temperature.   The catalyst oxygen storage amount control means controls to reduce the current catalyst oxygen storage amount of the catalytic converter when the estimated catalyst oxygen storage amount is larger than a predetermined value, and the estimated catalyst oxygen storage amount is less than the predetermined value. 2. The engine control device according to claim 1, wherein when the value is smaller, control is performed to increase the current catalytic oxygen storage amount of the catalytic converter.   When the estimated catalyst oxygen storage amount is greater than a predetermined value, the catalyst oxygen storage amount control means is configured to make the current catalyst oxygen storage amount of the catalytic converter smaller than half of the maximum value of the estimated catalyst oxygen storage amount. And when the estimated catalyst oxygen storage amount is smaller than the predetermined value, the current catalyst oxygen storage amount of the catalytic converter is controlled to be larger than half of the maximum value of the estimated catalyst oxygen storage amount. The engine control device according to claim 3. In an engine control method for controlling an engine in a vehicle equipped with an engine that sucks an air-fuel mixture and a catalytic converter that purifies exhaust gas exhausted from the engine with a catalyst,
By computer
An information acquisition means for acquiring vehicle state prediction information for predicting a state of the vehicle in a route through which the vehicle passes in the future;
The catalytic converter state estimating means estimates a vehicle speed change amount in the route based on the vehicle state prediction information, and calculates an estimated catalyst oxygen storage amount of the catalytic converter at a predetermined point based on the vehicle speed change amount. Estimating the state of the catalytic converter;
Based on the estimated catalyst oxygen storage amount, the catalyst oxygen storage amount control means sets a target catalyst oxygen storage amount of the catalytic converter that is a target before the predetermined point, and the current catalyst oxygen storage amount of the catalytic converter Controlling the amount to be the target catalyst oxygen storage amount;
An engine control method characterized in that the following process is executed.

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