JP6657744B2 - Engine control device - Google Patents

Description

  The present invention relates to an engine control device including a filter and a trap catalyst (hereinafter, these are also collectively referred to as a “processor”) that collect, occlude, and treat substances contained in exhaust gas.

  2. Description of the Related Art Conventionally, a filter for collecting particulate matter (PM) contained in exhaust gas of an engine and a trap catalyst for storing nitrogen oxides (NOx) and sulfur components (S) in exhaust gas. An engine provided with such a processor is known. In these processors, a control (hereinafter, referred to as “regeneration control”) for removing, by burning, desorbing, and reducing substances such as PM and NOx temporarily taken in, is performed. In this regeneration control, the temperature of the processor is raised to a temperature at which the substance taken into the processor can be burned, desorbed, and reduced.

  By the way, some vehicles equipped with an engine have an idling stop function. That is, the engine is automatically temporarily stopped and restarted in accordance with the stop and start of the vehicle. Such a vehicle has the merit that the fuel consumption can be reduced by idling stop, but also has the disadvantage that if idling is stopped during the execution of regeneration control, the regeneration control is interrupted and the temperature of the processor decreases. is there. On the other hand, if the idling stop condition is satisfied during the regeneration control, the processor temperature at that time is checked, and if the temperature is high, the engine is automatically stopped to save fuel consumption, and the temperature is reduced. If the temperature is low, a technique has been proposed in which automatic stop is prohibited and the temperature of the processor is maintained at a high state (for example, Patent Document 1).

International Publication No. 2011/070664 pamphlet

  When the engine is automatically stopped during the regeneration control, additional fuel for compensating for a decrease in the temperature of the processor during the stop of the engine is added to the fuel injection amount after the restart. This additional fuel may cause excessive combustion of the substance taken into the processor, resulting in an excessive temperature rise of the processor. In particular, when the amount of the substance taken into the processor is large, the calorific value is increased, so that the risk of excessive temperature rise is increased, and the processor is likely to be melted or deteriorated. Such an increase in the calorific value can be further promoted by a sharp increase in the oxygen concentration near the processing unit after the restart after the idling stop.

  The present invention has been devised in view of such a problem, and an object of the present invention is to provide an engine control device capable of suppressing an excessive rise in temperature of a processor while improving fuel efficiency by idling stop. It is to be noted that the present invention is not limited to this object, and it is another effect of the present invention that the present invention is an operation effect derived from each configuration shown in the embodiment for carrying out the invention described later, and that it has an operation effect that cannot be obtained by the conventional technology. Can be positioned.

(1) The engine control device disclosed herein is an engine control device that is mounted on a vehicle that performs an idling stop and includes a processor that captures a predetermined substance contained in exhaust gas and processes the substance. . The control device performs an estimating unit that estimates an amount of the substance trapped in the processor and a regeneration control that removes the substance from the processor when a predetermined regeneration condition is satisfied. A regeneration control unit, and when a predetermined idling stop condition is satisfied during the execution of the regeneration control, the engine of the engine is controlled based on the trapping amount at the time when the idling stop condition is satisfied during the execution of the regeneration control . A setting unit that sets a stop time, and when the stop time is set, an idling stop control unit that stops the engine for the stop time from the time when the idling stop condition is satisfied, and the setting unit includes: the collection amount is said to set a longer stop time as small as possible.

(2) The engine control device disclosed herein is mounted on a vehicle that performs an idling stop, and includes a processor that captures a predetermined substance contained in exhaust gas and processes the substance. It is. The control device may further include a trapping amount of the substance trapped in the processor and a removal amount of the substance removed from the processor since the regeneration control for removing the substance from the processor is started. An estimating unit for estimating and a regeneration control unit that performs the regeneration control when a predetermined regeneration condition is satisfied; and a regeneration control unit that performs the regeneration control when a predetermined idling stop condition is satisfied during the execution of the regeneration control. A setting unit for setting a stop time of the engine based on each of the trapping amount and the removal amount at the time when the idling stop condition is satisfied during the execution of the idling stop condition; and An idling stop control unit that stops the engine for the stop time from the time when the idling stop condition is satisfied. Serial with setting a longer stop time, and set longer as the stop time the removal amount is large, sets one short ones of the two said stop time as the stopping time.
The idling stop control unit may restart the engine when the engine is stopped (ie, during idling stop) and a predetermined restart condition is satisfied before the stop time elapses. Preferred .

(3) It is preferable that the idling stop control unit prohibits the idling stop when the trapped amount exceeds a first predetermined value that is a measure of an excessive temperature rise risk . That is, it is preferable that the idling stop control unit keeps the idling state without stopping the engine when the stop time is set to 0. In addition , it is preferable that the first predetermined value is a value set in advance in consideration of a relationship between the trapped amount and an overheating risk of the processor.

( 4 ) Preferably, the control device includes an exhaust gas temperature sensor for detecting at least one of the exhaust gas temperature on the upstream side and the downstream side of the processor. Further, when the exhaust gas temperature is equal to or lower than a first temperature set to a temperature at which the substance trapped in the processing device starts to be removed, the settling time decreases as the exhaust gas temperature decreases. It is preferable to perform the decrease correction .

( 5 ) Preferably, the control device includes an intake air temperature sensor that detects an intake air temperature. Further, it is preferable that, when the exhaust gas temperature is equal to or lower than the first temperature, the setting unit corrects the stop time so as to decrease as the intake air temperature is lower.
( 7 ) Preferably, the treatment device includes a trap catalyst capable of storing a sulfur component in exhaust gas. In this case, the regeneration control unit performs the S purge control for removing the sulfur component from the trap catalyst as the regeneration control, and the idling stop control unit sets the idling stop condition during the execution of the S purge control. When the condition is satisfied, it is preferable to prohibit the idling stop .

  The risk of excessive temperature rise of the processor can be determined from the amount of the substance trapped in the processor. For this reason, by setting the stop time based on the trapping amount, it is possible to suppress excessive temperature rise of the processor while improving fuel efficiency by idling stop.

FIG. 1 is a block diagram of a control device according to an embodiment and a schematic diagram of an engine to which the control device is applied. It is a map example which acquires a stop time, (a) is a map based on PM accumulation amount, (b) is a map based on PM combustion amount. It is an example of a map which acquires a coefficient for amending stop time, (a) is a map based on exhaust temperature of a filter upstream, and (b) is a map based on exhaust temperature of a filter downstream. It is an example of a map which acquires a coefficient for amending stop time based on intake air temperature. 9 is a flowchart illustrating a procedure of filter regeneration control. It is a flowchart which illustrates the procedure of idling stop control. It is a time chart for explaining the control contents, (a) shows a vehicle speed, (b) shows an engine speed, (c) shows a PM amount, and (d) shows a filter temperature. 5 is a time chart for explaining control contents, in which (a) shows a vehicle speed, (b) shows an engine speed, (c) shows a PM amount, (d) shows an upstream temperature, and (e) shows a downstream temperature.

  An engine control device as an embodiment will be described with reference to the drawings. Each embodiment described below is merely an example, and there is no intention to exclude various modifications and application of technology not explicitly described in the following embodiments. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. Further, they can be selected as needed, or can be appropriately combined.

[1. Device configuration]
FIG. 1 is a schematic diagram showing an engine 10 and a control device 1 for controlling the engine. The engine 10 of the present embodiment is a diesel engine serving as a drive source of a vehicle, and is mounted on, for example, an engine vehicle or a hybrid vehicle. The engine 10 has an idling stop function that automatically stops and restarts when the vehicle stops and starts. The cylinder head of the engine 10 is provided with an injector 11 for injecting fuel into the cylinder. An exhaust gas purification device 14 is provided in the exhaust passage 13 of the engine 10.

The exhaust gas purification device 14 is a system for purifying exhaust gas by removing harmful substances contained in exhaust gas, and includes an oxidation catalyst 14A, a filter 14B, and a trap catalyst 14C.
The oxidation catalyst 14A is a processor having an oxidizing ability for components in exhaust gas, and has a honeycomb-shaped carrier carrying a catalytic substance. The oxidation catalyst 14A has a function of purifying exhaust gas by taking in components such as nitrogen monoxide (NO), hydrocarbons (HC), and carbon monoxide (CO) and oxidizing the same, and raises the exhaust temperature by oxidizing heat at this time. With the function to make.

The filter 14B is a porous filter (processor) that traps PM contained in the exhaust gas, and purifies the exhaust gas by filtering and trapping the PM from the exhaust gas that passes through the inside. The PM trapped and accumulated in the filter 14B is burned and removed during normal running of the vehicle, and is also burned and removed by forcibly increasing the temperature of the filter 14B. The former is a system (continuous regeneration system) in which PM is burned on the filter 14B by mainly using nitrogen dioxide (NO ₂ ) in exhaust gas as an oxidizing agent. On the other hand, the latter is a method (forced regeneration method) in which PM is burned on the filter 14B by mainly using oxygen (O ₂ ) as an oxidizing agent. Hereinafter, the control for burning PM by the latter method is referred to as “filter regeneration control”, and the amount of PM (collection amount) deposited on the filter 14B is referred to as “PM accumulation amount A”. Further, the PM combustion amount (removal amount) based on the start time of the filter regeneration control is referred to as “PM combustion amount B”, and the PM accumulation amount A at the start time of the filter regeneration control is referred to as an initial accumulation amount A _START .

When the filter regeneration control is not being performed while the engine 10 is operating, the PM accumulation amount A gradually increases. On the other hand, the PM accumulation amount A during the filter regeneration control gradually decreases from the initial accumulation amount _ASTART . Correspondingly, the PM combustion amount B during the filter regeneration control gradually increases from zero. That is, the value of the PM accumulation amount A during the filter regeneration control corresponds to a value obtained by subtracting the PM combustion amount B from the initial accumulation amount A _START . Note that, since the conditions for starting the filter regeneration control include conditions other than the PM accumulation amount A, the initial accumulation amount A _START does not always have a constant value. In other words, the initial accumulation amount A _START is a variable value that can change according to the operating state of the engine 10.

The trap catalyst 14C (processor) is a processor for purifying NOx contained in the exhaust gas, and has a storage material supported on the surface of the reduction catalyst. The storage material has a function of storing NOx in exhaust gas in the form of nitrate under an oxidizing atmosphere and releasing NOx (nitrate) stored under a reducing atmosphere. The NOx released here is reduced to nitrogen (N ₂ ) or ammonia (NH ₃ ) by a reduction catalyst. Hereinafter, a control for reducing the _{N 2} by releasing NOx from the trap catalyst 14C is referred to as "NOx purge control".

  Further, not only NOx but also S contained in exhaust gas may accumulate in the storage material of the trap catalyst 14C. Since only a small amount of the accumulated S is released in the NOx purge control, the amount gradually increases, and the original function (NOx purification function) of the trap catalyst 14C decreases. Therefore, when the amount of accumulation increases, control is performed to release the accumulated S from the trap catalyst 14C. Hereinafter, this control is referred to as “S purge control”, and the amount of S (collected amount) accumulated in the trap catalyst 14C is referred to as “S accumulated amount E”. Further, the expression “regeneration control” is used as a general term for the above-described filter regeneration control and S purge control.

The intake passage 12 of the engine 10 is provided with an intake air temperature sensor 20 for detecting the temperature of intake air flowing through the intake passage 12 (intake air temperature T _IN ). The exhaust passage 13 has three exhaust gas temperature sensors 21, 22, 23 for detecting the temperature of the exhaust gas, an air-fuel ratio sensor 24 for detecting the air-fuel ratio of the exhaust gas, and a differential pressure between the upstream and downstream of the filter 14 </ b> B (front-back And a differential pressure sensor 25 for detecting the pressure P). The exhaust gas temperature sensor 21 is disposed between the oxidation catalyst 14A and the filter 14B, and detects the temperature on the upstream side of the filter 14B (hereinafter, referred to as “upstream temperature T _F ”). The exhaust gas temperature sensor 22 is disposed immediately downstream of the filter 14B, and detects a temperature on the downstream side of the filter 14B (hereinafter, referred to as “downstream temperature T _R ”). The exhaust gas temperature sensor 23 is disposed immediately upstream of the NOx trap catalyst 14C, and detects a temperature on the upstream side of the NOx trap catalyst (hereinafter, referred to as a “downstream temperature T _C ”). Information detected by these sensors 20 to 25 is transmitted to control device 1.

  The control device 1 is a computer that comprehensively controls the engine 10, and is connected to a communication line of a vehicle-mounted network. The control device 1 is an electronic device (ECU, ECU, etc.) in which a microprocessor such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a nonvolatile memory, and the like are integrated. Electronic control unit). The processor referred to here is, for example, a processing device (processor) including a control unit (control circuit), an operation unit (operation circuit), a cache memory (register), and the like. The ROM, the RAM, and the nonvolatile memory are memory devices that store programs and working data. The contents of the control performed by the control device 1 are recorded as firmware and application programs in ROM, RAM, nonvolatile memory, and removable media. When the program is executed, the contents of the program are expanded in a memory space in the RAM and executed by the processor.

[2. Control configuration]
The control device 1 has a function of controlling automatic stop and restart of the engine 10 (idling stop control function). That is, the control device 1 stops the fuel injection from the injector 11 to automatically stop the engine 10 when a predetermined idling stop condition is satisfied, and when the predetermined restart condition is satisfied during the stop. The engine 10 is restarted.

  Further, the control device 1 has a function of performing the above-described filter regeneration control and S purge control. All of these controls are controls (regeneration control) for restoring the purification performance of the exhaust gas purification device 14. The NOx purge control is also a control for restoring the purification performance of the exhaust gas purification device 14, but is excluded from the "regeneration control" referred to in the present embodiment. In the filter regeneration control, a predetermined amount of fuel is post-injected from the injector 11, and the temperature of the filter 14B is raised to the PM combustion temperature or higher. In the S purge control, a predetermined amount of fuel is post-injected from the injector 11, the surrounding atmosphere of the trap catalyst 14C is reduced to a reducing atmosphere, and the temperature of the trap catalyst 14C is raised to a temperature at which S can be released.

  As elements for performing such control, the control device 1 is provided with an estimation unit 2, a reproduction control unit 3, an idling stop control unit 4, and a setting unit 5. These show some functions of a program executed by the control device 1, and are realized by software. However, some or all of the functions may be realized by hardware (electronic control circuit), or may be realized by using software and hardware together.

[2-1. Estimation unit]
The estimating unit 2 estimates the PM accumulation amount A, the PM combustion amount B, and the S accumulation amount E. Various known techniques can be applied to these estimation methods. For example, as a method of estimating the PM accumulation amount A, the amount of PM discharged from the engine 10 is estimated based on the rotation speed, the engine load, and the like of the engine 10, and this is integrated after the end of the previous filter regeneration control. And an estimation method based on the differential pressure between the upstream and downstream of the filter 14B. Further, as a method of estimating the PM combustion amount B, a method of estimating based on the execution time of the filter regeneration control, the temperature of the exhaust gas (upstream temperature T _F , the downstream temperature T _R ), the exhaust gas flow rate, etc. Method based on the change in the differential pressure of

The estimating unit 2 estimates the PM combustion amount B using a parameter different from the parameter used for estimating the PM accumulation amount A. The estimating unit 2 of the present embodiment estimates the PM accumulation amount A based on the differential pressure P detected by the differential pressure sensor 25 while the engine 10 is operating. Further, during the operation of the engine 10 and during the execution of the filter regeneration control, the PM combustion amount B is also estimated based on a parameter other than the front-rear differential pressure P. That is, instead of estimating (calculating) the PM combustion amount B using the PM accumulation amount A, these two PM amounts are estimated separately (independently). Therefore, a value (A _START −B) obtained by subtracting the PM combustion amount B estimated at a predetermined time from the PM accumulation amount A estimated at the start of the filter regeneration control (that is, the initial accumulation amount A _START ) is obtained at that time. Does not always coincide with the value of the PM accumulation amount A estimated in step (1).

  As a method of estimating the S accumulation amount E, there is a method of integrating the amount of fuel used since the end of the previous S purge control and multiplying the integrated amount of used fuel by a coefficient corresponding to the type of fuel. The estimation unit 2 estimates the S accumulation amount E based on these parameters while the engine 10 is operating. When the S purge control is not performed, the S accumulation amount E increases according to the used fuel amount. On the other hand, during the execution of the S purge control, S accumulated in the trap catalyst 14C is desorbed and reduced, so that the S accumulation amount E gradually decreases. The amount of S released during the S purge control is estimated based on, for example, the S accumulation amount E, the air-fuel ratio, the temperature, the flow rate, and the like of the exhaust gas. The estimation unit 2 transmits the estimation result to the reproduction control unit 3.

[2-2. Playback control section]
The regeneration control unit 3 performs regeneration control (filter regeneration control, S purge control) of the exhaust gas purification device 14 when a predetermined regeneration condition is satisfied. Here, start conditions and end conditions for each of the two reproduction controls are individually determined and implemented. The start condition and the end condition are appropriately set. For example, the PM accumulation amount A and the S accumulation amount E estimated by the estimation unit 2 may be included in the start condition, or the PM accumulation amount A, the PM combustion amount B, and the S accumulation amount E may be included in the end condition. Is also good. These two reproduction controls can be performed simultaneously (at the same time).

[2-3. Idling stop control section]
The idling stop control unit 4 controls the idling stop of the engine 10. Here, when the idling stop condition is satisfied during operation of the engine 10, control for automatically stopping the engine 10 (idling stop) is performed. When the restart condition is satisfied during the automatic stop, control for restarting the engine 10 is performed. However, if any of the regeneration controls is performed at the time when the idling stop condition is satisfied, control for restarting the engine 10 is performed at the time when the stop time ts has elapsed from the time when the idling stop condition is satisfied. You. This restart is performed even if the restart condition is not satisfied. The stop time ts is set in a range of 0 second or more.

As described above, the execution time of the idling stop during the reproduction control is shorter than when the reproduction control is not performed. That is, when the reproduction control is being performed at the start of the idling stop, at least the execution time of the idling stop is reduced, and in some cases, the idling stop itself is prohibited. As a result, a decrease in the temperature of the filter 14B and the trap catalyst 14C is suppressed, and an excessive rise in the temperature of the filter 14B and the trap catalyst 14C due to post-injection after restart is suppressed.
When it is determined that the idling stop condition is satisfied, the idling stop control unit 4 transmits the result to the setting unit 5. When the idling stop control unit 4 determines that the “restart condition is satisfied”, it transmits the result to the setting unit 5. These conditions are set as appropriate.

[2-4. Setting section]
When the idling stop condition is satisfied during the execution of the regeneration control, the setting unit 5 sets the engine 10 on the basis of the trapping amount (PM accumulation amount A, S accumulation amount E) estimated by the estimation unit 2 at that time. The stop time ts is set. The stop time ts set here corresponds to the maximum time during which the idling stop state can be maintained (idling stop time). In other words, if the engine 10 is automatically stopped when the stop time ts elapses from the time when the idling stop condition is satisfied, the engine 10 is restarted even if the restart condition has not been satisfied. During the automatic stop of the engine 10, all the regeneration controls are interrupted.

The setting unit 5 sets the stop time ts using a parameter corresponding to the type of the reproduction control that was performed when the idling stop condition was satisfied, and transmits the set stop time ts to the idling stop control unit 4. . For example, in the case of the filter regeneration control, the stop time ts is set based on the PM accumulation amount A and the PM combustion amount B, and in the case of the S purge control, the stop time ts is set based on the S accumulation amount E. .
In the following description, three types of setting methods regarding the stop time ts will be described by taking the case of filter regeneration control as an example.

  The first setting method is to set the stop time ts based on only the PM accumulation amount A. The second setting method is to set the stop time ts using both the PM accumulation amount A and the PM combustion amount B. The third setting method is to set the stop time ts using one of the first and second setting methods, and then correct the stop time ts according to the exhaust gas temperature around the filter 14B. The stop time ts can be set using any of the three setting methods. In the present embodiment, the filter regeneration control is started due to the PM accumulation amount A (for example, because the PM accumulation amount A is large). When the filter regeneration control is started regardless of the PM accumulation amount A (in a state where the PM accumulation amount A is small), the third setting method is adopted.

  In the first setting method, the smaller the PM accumulation amount A when the idling stop condition is satisfied, the longer the stop time ts is set. This is because the smaller the PM accumulation amount A, the lower the risk of excessive temperature rise of the filter 14B after the restart after the automatic stop, and therefore, the longer the stop time ts, the better the fuel efficiency. The setting unit 5 sets the stop time ts using a map, an arithmetic expression, or the like that defines the relationship between the PM accumulation amount A and the stop time ts. The map, the arithmetic expression, and the like are stored in the control device 1 in advance.

The setting unit 5 sets the stop time ts to 0 when the PM accumulation amount A exceeds the first predetermined value A1, and sets the stop time ts within a range of the minimum time ts ₀ or more when the PM accumulation amount A is equal to or less than the first predetermined value A1. . The first predetermined value A1 is a value that is set in advance in consideration of the relationship between the amount of PM deposited on the filter 14B and the risk of excessive temperature rise of the filter 14B. When the PM accumulation amount A is larger than the first predetermined value A1, priority is given to avoiding the risk of excessive temperature rise over improvement in fuel economy, and the stop time ts is set to 0. In this case, even if the idling stop condition is satisfied, the engine 10 is not automatically stopped (the operating state is maintained).

Minimum time ts ₀ is preset to such time as the passenger does not have a sense of discomfort by idling stop (for example, about 10 seconds). If the engine 10 is not restarted after the automatic stop until the stop time ts elapses, the engine 10 restarts without any operation by the occupant. Therefore, if the time from the automatic stop of the engine 10 to the restart (stop time ts) is too short, the occupant may feel uncomfortable. In contrast, setting unit 5 of the present embodiment, since the PM accumulation amount A if: first predetermined value A1 is set to at least the minimum time ts ₀ or more values downtime ts, discomfort the occupant Is difficult to give.

FIG. 2A is an example of a map used in the setting unit 5. This map defines the relationship between the PM accumulation amount A and the stop time ts, and here, a solid line graph and a dashed line graph are exemplified. These two graphs differ in how the stop time ts changes when the PM accumulation amount A is less than the first predetermined value A1. Specifically, the solid line graph is set so that the stop time ts increases stepwise as the PM deposition amount A decreases, and the dashed line graph indicates that the stop time ts gradually decreases as the PM deposition amount A decreases. It is set to be longer (with a constant slope). In any graph, when the PM accumulation amount A is larger than the first predetermined value A1, the stop time ts is set to 0, and when the PM accumulation amount A is the first predetermined value A1, the stop time is set. ts is set to the minimum time ts _0.

  In the second setting method, as the PM accumulation amount A when the idling stop condition is satisfied and the PM combustion amount B increase, the stop time ts is set longer. Since the PM accumulation amount A and the PM combustion amount B are estimated based on mutually different parameters, setting the stop time ts using these two PM amounts A and B further suppresses the excessive temperature rise of the filter 14B. Is done. Thereby, even if each of the two PM amounts A and B has an error with respect to the actual value, for example, the two PM amounts A and B are weighted to reduce the risk of overheating, By preferentially using one of the PM amounts that reduces the risk of excessive heating, excessive heating after restart can be suppressed.

As a specific method of setting the stop time ts in consideration of not only the PM accumulation amount A but also the PM combustion amount B, a three-dimensional method in which the relationship between the PM accumulation amount A and the PM combustion amount B and the stop time ts is defined. There is a method of storing a map, an arithmetic expression, and the like in advance. Alternatively, there is a method in which a map defining the relationship between the PM combustion amount B and the stop time (second stop time ts _B ) is stored in advance separately from the map of FIG. This map is illustrated in FIG.

The map in FIG. 2B is a map that defines the relationship between the PM combustion amount B and the stop time (second stop time ts _B ). Here, a solid line graph and a dash-dot line graph are illustrated. These two graphs, the manner of change of the second stop time ts _B in range PM combustion amount B of the second predetermined value or more B1 is different. Specifically, the solid line in the graph, the greater the number PM combustion amount B is second stop time ts _B is set to be longer stepwise graph of one-dot chain line, the second stop The more PM combustion quantity B time ts _B is set so as to gradually become longer (with a constant gradient). In any graphs, the PM combustion amount B when less than the second predetermined value B1 is set to the second stop time ts _B is 0, if the PM combustion amount B is a second predetermined value B1 It is ts _B second stop time set in the minimum time ts ₀ is.

In this case, setting unit 5, the value obtained from the map shown in FIG. 2 (a) based on the PM accumulation amount A as the first stop time ts _A, from the map shown in FIG. 2 (b) based on the PM combustion amount B the obtained value second stop time and ts _B. Then, by setting a shorter one of the first stop time ts _A and the second stop time ts _B as the stop time ts, a value on the safer side (lower risk of excessive temperature rise) is adopted, and the filter 14B Increase the protection of

In the third setting method, a correction is made such that the lower the exhaust gas temperature around the filter 14B is, the shorter the stop time ts is based on the above stop time ts. That is, when setting unit 5, upstream and downstream of at least one of the exhaust temperature of the filter 14B (upstream temperature T _F at the time of establishment of the idle stop condition, at least one of the downstream temperature T _R) is relatively low The set stop time ts is corrected based on the exhaust gas temperature. In this case, the setting unit 5 sets the corrected value (correction stop time ts') as a new stop time ts and transmits the new stop time ts to the idling stop control unit 4.

In the correction of the stop time ts, both the upstream temperature T _F and the downstream temperature T _R may be used. Specifically, the setting unit 5 obtains two coefficients K1 and K2 from the maps shown in FIGS. 3A and 3B and corrects the stop time ts according to the following equation 1. Each of the coefficients K1 and K2 is a coefficient for correcting the stop time ts, and is a value of 0 or more and 1 or less (0 ≦ K1 ≦ 1, 0 ≦ K2 ≦ 1).
Correction stop time ts' = ts × K1 × K2 Equation 1

3 (a) is an example map defining the relationship between the upstream temperature T _F and the first coefficient K1, FIG. 3 (b), the map to define the relationship between the downstream temperature T _R and the second coefficient K2 It is an example. These maps are stored in the control device 1 in advance. The first coefficient K1 is set to 1 when the upstream temperature _TF is equal to or higher than the first upstream temperature _TF1 (first temperature), and is set to 0 when the upstream temperature _TF is equal to or lower than the second upstream temperature _TF2 (second temperature). Is set. Also, higher upstream temperature T _F than the second upstream temperature T _F2, and, when it is less than the first upstream temperature T _F1, the first coefficient K1 is set to be larger with a constant gradient.

The second coefficient K2 is set to 1 if the downstream temperature T _R is first downstream temperature T _R1 (first temperature) or higher, to zero if second downstream temperature T _R2 is (second temperature) or less Is set. Also, higher downstream temperature T _R than second downstream temperature T _R2, and, if it is less than the first downstream temperature T _R1, the second coefficient K2 is set to be larger with a constant gradient. Each of the first upstream temperature T _F1 and the first downstream temperature T _R1 is set to, for example, a temperature at which PM starts burning on the filter 14B. Further, each of the second upstream temperature _TF2 and the second downstream temperature _TR2 is a temperature lower than the first upstream temperature _TF1 and the first downstream temperature _TR1 , for example, a temperature sufficiently lower than the combustion start temperature of PM. Is set to Each of the two first temperatures T _F1 and T _R1 and the two second temperatures T _F2 and T _R2 may be set to the same temperature or may be set to different temperatures. For example, since the temperature of the exhaust gas on the upstream side of the filter 14B tends to increase more than that of the exhaust gas on the downstream side, T _F1 > T _R1 may be set so that the stop time ts is easily corrected.

Therefore, if the setting unit 5, when the exhaust temperature T _F, the T _R is below the first temperature T _F1, T _R1, i.e. upstream temperature T _F is below the first upstream temperature T _F1, or downstream temperature T _{When R} is equal to or lower than the first downstream temperature T _R1 , the stop time ts is reduced and corrected as the exhaust temperatures T _F and T _R are lower. Also, if the setting unit 5, when the exhaust temperature T _F, T _R is below the second temperature T _F2, T _R2, or upstream temperature T _F is below the second upstream temperature T _F2, or downstream temperature T If _R is less than second downstream temperature T _R2 corrects the stop time ts to 0. As a result, the idling stop is prohibited, and the temperatures of the filter 14B and the trap catalyst 14C are quickly raised.

When the exhaust temperatures T _F and T _R are higher than the first temperatures T _F1 and T _R1 , the set stop time ts is not changed because both the coefficients K1 and K2 are 1. Specifically, when PM is burning on the filter 14B, since the exhaust temperatures T _F and T _R are naturally higher than the first temperatures T _F1 and T _R1 , both of the coefficients K1 and K2 are different. It becomes 1 and the correction based on the exhaust temperatures T _F and T _R is not substantially performed. Also, when the filter regeneration control is started in the high PM accumulation amount A than the first predetermined value A1, since it is set to the stop time ts is 0, the exhaust gas temperature T _F, even if T _R is lower Also, the stop time ts becomes 0. That is, when the filter regeneration control is started with the PM accumulation amount A larger than the first predetermined value A1 and when PM is already burning, the stop time ts is corrected by the exhaust gas temperatures T _F and T _R. And the value set based on the PM accumulation amount A and the like is maintained. In other words, the setting unit 5 corrects the stop time ts according to the exhaust gas temperatures T _F and T _R at least when the filter regeneration control is started with the PM accumulation amount A less than the first predetermined value A1. .

[3. flowchart]
[3-1. Filter regeneration control]
FIG. 5 is a flowchart illustrating a control procedure of the filter regeneration control. This flow is repeatedly performed at a predetermined cycle while, for example, an ignition key switch (main switch) of the vehicle is on. The flag F used in this flow indicates the execution state of the filter regeneration control, and is set to F = 1 during the execution of the filter regeneration control. It is assumed that the estimation unit 2 always estimates the PM accumulation amount A and the like separately from this flow.

  First, various information used for the determination of the filter regeneration control is obtained (step Y1). The information acquired here includes the PM accumulation amount A estimated by the estimation unit 2. If the flag F is F = 0 (step Y2), it is determined whether a condition for starting the filter regeneration control is satisfied (step Y3). When the start condition is satisfied, the flag F is set to F = 1 (step Y4), the filter regeneration control is started (step Y7), and the control in this calculation cycle ends. If the start condition is not satisfied, the control in this calculation cycle ends as it is (with F = 0).

  During execution of the filter regeneration control in which the flag F becomes F = 1, it is determined whether or not a condition for terminating the filter regeneration control is satisfied (step Y8). If the end condition is not satisfied, the control in this calculation cycle ends, and the filter regeneration control is continued. On the other hand, when the end condition is satisfied, the filter regeneration control ends (step Y9), the flag F is set to F = 0 (step Y10), and the control in this calculation cycle ends.

[3-2. Idling stop control]
FIG. 6 is a flowchart illustrating a procedure of control for automatically stopping and restarting the engine 10 (idling stop control). This flow is repeatedly performed at a predetermined cycle while, for example, an ignition key switch (main switch) of the vehicle is on. This flow is performed in parallel with the flow shown in FIG. 5, and uses the information of the flag F set in the flow of FIG. The flag G used in this flow indicates the automatic stop state of the engine 10, and is set to G = 1 during the automatic stop. It is assumed that the estimation unit 2 always estimates the PM accumulation amount A and the like separately from this flow.

  First, various information used for the determination of the idling stop control is obtained (step Z1). The information acquired here includes the PM accumulation amount A and the PM combustion amount B estimated by the estimation unit 2. If the flag G is G = 0 (step Z2), it is determined whether or not the idling stop condition is satisfied (step Z3). If the idling stop condition is satisfied, the process proceeds to step Z4. If the idling stop condition is not satisfied, the control in this calculation cycle ends, and the operating state of the engine 10 is maintained.

In step Z4, it is determined whether or not the flag F is F = 0. That is, it is determined whether or not the filter regeneration control is being performed. If the filter regeneration control is not performed (if F = 0), the engine 10 is automatically stopped (step Z5), and the flag G is set to G = 1 (step Z6). Is terminated. On the other hand, if F = 0, the first stop time ts _A is obtained based on the PM accumulation amount A, and the second stop time ts _B is obtained based on the PM combustion amount B, and the shorter value is obtained. Is set to the stop time ts (step Z8, second setting method). Although the above-described second setting method is exemplified here, the first method may be adopted.

Then, the upstream temperature T _F, the first coefficient based on the downstream temperature T _R K1, the second coefficient K2 is obtained (Step Z10), is corrected set stop time ts at step Z8, a new stop time ts Are set (steps Z11, Z12, third setting method). Then, in step Z13, the engine 10 is automatically stopped, the flag G is set to G = 1 (step Z14), a timer is started (step Z15), and the control in this calculation cycle ends. This timer measures the automatic stop time.

  Since the flag G is set to G = 1 during the automatic stop of the engine 10, the process proceeds from step Z2 to step Z16. In step Z16, it is determined whether or not the restart condition is satisfied. If so, the engine 10 is restarted (step Z19). On the other hand, if the restart condition is not satisfied, it is determined whether the value counted by the timer is equal to or longer than the stop time ts set in step Z12 (step Z17). That is, it is determined whether or not the elapsed time after the automatic stop of the engine 10 is equal to or longer than the stop time ts. If the stop time is equal to or longer than the stop time ts, the engine 10 is restarted (step Z19).

  If the timer value is not equal to or longer than the stop time ts, the control in this calculation cycle ends with the engine 10 automatically stopped. On the other hand, when the engine 10 is restarted in step Z19, the flag G is set to G = 0 (step Z20). When the timer is counting, the count is stopped and reset (step Z21). The control in this calculation cycle ends.

[4. Action]
The filter regeneration control will be described with reference to FIGS. FIGS. 7A to 7D are time charts when the filter regeneration control is started with the PM accumulation amount larger than the first predetermined value A1 at which the risk of excessive temperature rise of the filter 14B is high, and FIG. FIGS. 9A to 9E are time charts when the filter regeneration control is started with a PM accumulation amount smaller than the first predetermined value A1 in which the risk of excessive temperature rise of the filter 14B is low.

As shown in FIG. 7 (a), the filter regeneration control is started at time t _0, when the idling stop condition is satisfied at time t _1, PM accumulation amount A at the time t _1, based on the PM combustion amount B The first stop time ts _A and the second stop time ts _B are obtained. As shown in FIG. 7 (c), the time t ₁ the PM deposition amount A more than the first predetermined value A1, since the PM combustion amount B is less than the second predetermined value B1, the first stop time ts _A , the second stop time ts _B is next to 0 none, "stop time ts = 0" is set. Therefore, as shown in FIG. 7 (b), at time t ₁ the idling stop is prohibited, the predetermined idle speed Ne ₀ is maintained.

As shown in FIGS. 7C and 7D, when the filter temperature becomes high, PM starts burning on the filter 14B, and the PM accumulation amount A decreases and the PM combustion amount B increases. Again the idling stop condition is satisfied at time t _3, the PM accumulation amount A at the time t ₃ is less than the first predetermined value A1, since the PM combustion amount B is greater than the second predetermined value B1, the first For both the stop time ts _A and the second stop time ts _B , values equal to or longer than the minimum time ts ₀ are obtained. Then, a shorter one of the two stop times ts _A and ts _B is set as the stop time ts.

Therefore, the engine 10 at time t _3, together with the automatically stopped, while the elapse of the stop time ts from the time t ₃ is maintained idling stop state. This reduces fuel consumption. Also, during which restart condition is the case where not satisfied, the engine 10 is restarted at time t ₄ when the stop time ts has elapsed. Therefore, the amount of decrease in the filter temperature during the automatic stop is suppressed, the post injection amount required after the restart is reduced, and the excessive temperature rise of the filter 14B after the restart is suppressed.

When the filter regeneration control again idling stop condition at the time t ₆ was approaching late is satisfied, the stop time ts is set at the time t ₆ is relatively long. Therefore, the engine 10 at time t _6, along with the automatic stop, for example, if satisfied restart condition is at time t ₇ before the stop time ts elapses, the engine 10 is restarted at the time t _7. As a result, it is possible to obtain a fuel efficiency effect by idling stop.

On the other hand, as shown in FIG. 8 (c), illustrating a case where the time t ₁₀ to the PM accumulation amount A initiates the filter regeneration control is less than a first predetermined value A1. As shown in FIG. 8 (a), when the idling stop condition at time t ₁₁ is established, with the stop time ts is set based on the PM accumulation amount A at the time t _11, the upstream temperature T _F, the downstream temperature coefficient K1 based on the T _R, K2 is obtained. As shown in FIGS. 8D and 8E, the exhaust gas temperatures T _F and T _R increase from the upstream side. At time t _10, the downstream temperature T _R is second downstream temperature T second coefficient K2 from lower than _R2 is zero, the set stop time ts is corrected to 0. Therefore, as shown in FIG. 8 (b), at time t ₁₁ the idling stop is prohibited, the predetermined idle speed Ne ₀ is maintained.

Again the idling stop condition at time t ₁₃ is satisfied, the stop time ts is set based on the PM accumulation amount A at the time t _13. Since this in the time t ₁₃ PM is not beginning to be burned, the same value as the stop time ts which is set to the time t ₁₁ is set. On the other hand, the upstream temperature T _F at this point t ₁₃ the first for the first coefficient K1 because it exceeds the first upstream temperature T _F1 1, and the the downstream temperature T _R is over the second downstream temperature T _R2 The two coefficient K2 is a value larger than 0. That is, the corrected stop time ts' does not become 0, but becomes a value smaller by the second coefficient K2, and is set as a new stop time ts.

Therefore, the engine 10 at time t _13, along with the automatically stopped, while the elapse of the stop time ts from the time t ₁₃ is maintained idling stop state. This reduces fuel consumption. Also, during which restart condition is the case where not satisfied, the engine 10 is restarted at time t ₁₄ the stop time ts has elapsed. Therefore, the amount of decrease in the filter temperature during the automatic stop is suppressed, and the temperature rise of the filter 14B is promoted.

Downstream temperature T _R also again the idling stop condition at time t ₁₆ which exceeds the first downstream temperature T _R1 is satisfied, since the the time t ₁₆ coefficients K1, K2 is 1 both, based on the PM accumulation amount A The set stop time ts is maintained as it is. Therefore, the engine 10 at time t _16, along with the automatic stop, for example, if satisfied restart condition is at time t ₁₇ before the stop time ts elapses, the engine 10 is restarted at the time t _17. As a result, it is possible to obtain a fuel efficiency effect by idling stop.

[5. effect]
(1) In the control device 1, when the idling stop condition is satisfied during the execution of the regeneration control, the stop time ts is set based on the trapping amount (PM accumulation amount A), and the idling stop condition is set. During the stop time ts from the time of establishment, the engine 10 is automatically stopped. Since the risk of excessive temperature rise of the processor such as the filter 14B and the trap catalyst 14C after the restart after the idling stop increases as the trapping amount increases, the stop time ts is set based on the trapping amount. The risk of temperature rise can be avoided. Therefore, it is possible to suppress an excessive rise in the temperature of the processor after restarting while improving fuel efficiency by idling stop.

  (2) In the above-described control device 1, for example, as shown in FIG. 2A, the smaller the trapping amount, the longer the stop time ts is set. This setting is derived from the fact that the smaller the trapping amount, the smaller the calorific value of the substance after the restart, and hence the lower the risk of excessive temperature rise of the processor after the restart after the idling stop. That is, by setting the stop time ts to be longer as the trapping amount is smaller, it is possible to improve fuel economy by idling stop while suppressing excessive temperature rise.

  (3) In the above controller 1, when the trapping amount (PM deposition amount A) exceeds the first predetermined value A1, the stop time ts is set to zero. That is, when the amount of the substance trapped in the processor is large, the idling stop is prohibited and the engine 10 remains operating even when the idling stop condition is satisfied. Thus, it is possible to prevent the temperature of the processor from being excessively increased after the restart.

(4) In the above-described control device 1, when the amount of collection (PM deposition amount A) is less than the first predetermined value A1, is set to the stop time ts is the minimum time ts ₀ or more. That is, when the idling stop is carried out is at least the minimum time ts ₀ is reserved until restarted regardless of the occupant's operation. Therefore, it is possible to avoid a situation in which the engine 10 is restarted immediately after the idling stop, and it is possible to prevent the occupant from feeling uncomfortable.

(5) In the above-described control device 1, of the first stop time ts _A obtained on the basis of the PM deposition amount A, a second stop time ts _B obtained based on the PM combustion amount B, a short while Is set as the stop time ts. In this way, by estimating not only the PM accumulation amount A but also the PM combustion amount B and setting the final stop time ts based on the respective PM amounts A and B, the estimation error is taken into account, A value on the safe side (the side with a lower risk of overheating) can be set. Thereby, the protection of the filter 14B can be further improved.

(6) In the above-described control device 1, the exhaust temperature T _F, T _R is the first temperature T _F1, when it is T _R1 less, the exhaust gas temperature T _F, T as _R is lower stop time ts is reduced corrected . That is, when the exhaust gas has not risen to the first temperatures T _F1 and T _R1 , the stop time ts set based on the trapping amount is corrected to be short. This correction is derived from the fact that there is no risk of excessive temperature rise of the processor, but rather it is preferable to raise the temperature of the processor early to advance the regeneration control. That is, when the exhaust temperatures T _F and T _R are equal to or lower than the first temperatures T _F1 and T _R1 , the stop time ts of the engine 10 is shortened, so that the temperature rise of the processor can be promoted and the regeneration time can be reduced can do. Thereby, the amount of fuel consumed in the regeneration control can be reduced.

(7) In the control device 1, when the exhaust temperatures T _F and T _R are equal to or lower than the second temperatures T _F2 and T _R2 , the stop time ts is corrected to 0. More promoted. As a result, the regeneration time can be reduced, and the amount of fuel consumed in the regeneration control can be reduced.
In the above-described embodiment, the temperature T _F on the upstream side and the temperature T _R on the downstream side of the filter 14B are used as the exhaust temperature, and the coefficients K1 and K2 corresponding to the respective temperatures T _F and T _R are obtained. Thus, the stop time ts is corrected. Filter 14B from being large components of relatively heat capacity, the downstream temperature T _R is compared to the upstream temperature T _F is the rate of temperature change is reduced. In other words, there is a characteristic that the upstream temperature T _F easily changes according to the operating state of the engine 10 (the change responsiveness is high), while the downstream temperature T _R is hard to change. Thus characteristics of two different exhaust temperature T _F, by using the T _R to correct the stop time ts, it is possible to set a more appropriate stopping time ts.

[6. Others]
In the above-described embodiment, the filter regeneration control has been described as an example of the regeneration control. However, during the execution of the S purge control by the regeneration control unit 3, the setting unit 5 sets the idling stop condition by the idling stop control unit 4. When it is determined that “established”, the stop time ts may be set based on the S accumulation amount E estimated by the estimation unit 2.

  When the idling stop condition is satisfied during the execution of the S purge control, the setting unit 5 preferably sets the stop time ts to 0. This is because the S purge control requires a higher temperature than the filter regeneration control and the NOx purge control. That is, it is preferable to maintain the high temperature state without stopping the engine 10 even when the idling stop condition is satisfied until the S purge control ends. As a result, it is possible to prevent the S purge control from being prolonged, and to reduce the amount of fuel consumed in the S purge control.

  As described above, if the regeneration control unit 3 continuously performs the S purge control immediately after the end of the filter regeneration control, the high temperature state in the filter regeneration control can be taken over to the S purge control. Therefore, the amount of temperature rise can be reduced. However, in this case, as shown in FIG. 7B, the stop time ts set to 0 in the initial stage of the filter regeneration control is set to a longer time as the control proceeds, and the filter regeneration control is started. When the process ends and the S purge control is started, it is set to 0 again. For this reason, although the idling was stopped before the start of the S purge control (at the end of the filter regeneration control), the idling was not stopped after the shift to the S purge control, which might give a passenger an uncomfortable feeling.

On the other hand, the setting unit 5 sets the stop time ts to the minimum time ts ₀ only when the S purge control is performed continuously from the filter regeneration control and the idling stop condition is first satisfied. It is possible to do. That is, even when the S purge control is being performed, if the S purge control is continuously performed from the filter regeneration control, the stop time ts is not immediately set to 0, but is set to the minimum time ts ₀ only once. Set to. As a result, the uncomfortable feeling given to the occupant can be reduced, and the amount of temperature decrease of the trap catalyst 14C during the automatic stop of the engine 10 can be minimized.

In the above embodiment, the upstream temperature T _F, a case has been exemplified for correcting the downstream temperature T _R downtime ts using both, in addition to this, the setting unit 5, either one of the exhaust temperature T _F , T _R are equal to or lower than the first temperatures T _F1 , T _R1 , the stop time ts may be reduced and corrected as the intake air temperature T _IN is lower. For example, the setting unit 5 applies the intake air temperature T _IN to the map shown in FIG. 4 to obtain a coefficient (third coefficient) K3 for correcting the stop time ts, and obtains the coefficient K3 on the right side of the above equation (1). It is conceivable to add a multiplication term. By correcting the stop time ts in consideration of the intake air temperature T _IN as described above, the temperature rise of the processor can be promoted, so that the regeneration time can be further reduced, and the combustion consumed in the regeneration control can be reduced. The amount can be reduced. Incidentally, omitted setting unit 5, the upstream temperature T _F, may be corrected stopping time ts based on the one of the temperature of the downstream temperature T _R, a correction based on the exhaust temperature T _F, T _R May be.

REFERENCE SIGNS LIST 1 control device 2 estimation unit 3 regeneration control unit 4 idling stop control unit 5 setting unit 10 engine 14 exhaust purification device 14B filter (processor)
14C trap catalyst (processor)
20 Intake temperature sensor 21, 22, 23 Exhaust temperature sensor
A PM accumulation amount (collected amount)
A1 First predetermined value
B PM combustion amount (removal amount)
B1 Second predetermined value
ES storage amount (collected amount)
ts downtime
ts ₀ minimum time
T _F upstream temperature (upstream exhaust temperature)
T _F1 first upstream temperature (first temperature)
T _F2 Second upstream temperature (second temperature)
T _R downstream temperature (downstream exhaust temperature)
T _R1 First downstream temperature (first temperature)
T _R2 Second downstream temperature (second temperature)

Claims (6)

An engine control device mounted on a vehicle that performs idling stop and having a processor that captures a predetermined substance contained in exhaust gas and processes the substance.
An estimator for estimating the amount of the substance trapped in the processor,
When a predetermined regeneration condition is satisfied, a regeneration control unit that performs regeneration control for removing the substance from the processor,
When a predetermined idling stop condition is satisfied during the execution of the regeneration control, a stop time of the engine is set based on the trapping amount at the time when the idling stop condition is satisfied during the execution of the regeneration control. A setting section,
An idling stop control unit that stops the engine for the stop time from the time when the idling stop condition is satisfied, when the stop time is set ,
The control device for an engine, wherein the setting unit sets the stop time longer as the trapping amount decreases. An engine control device mounted on a vehicle that performs idling stop and having a processor that captures a predetermined substance contained in exhaust gas and processes the substance.
Estimation for estimating the trapped amount of the substance trapped in the processor and the removal amount of the substance removed from the processor after the regeneration control for removing the substance from the processor is started Department and
A reproduction control unit for a predetermined reproduction condition is when a condition is satisfied, carrying out the pre-Symbol playback control,
When a predetermined idling stop condition is satisfied during the execution of the regeneration control, the engine is executed based on each of the trapping amount and the removal amount at the time when the idling stop condition is satisfied during the execution of the regeneration control. A setting section for setting the stop time of the
An idling stop control unit that stops the engine for the stop time from the time when the idling stop condition is satisfied, when the stop time is set ,
The setting unit sets the stop time longer as the trapping amount is smaller, and sets the stop time longer as the removal amount is larger, and sets the shorter one of the two stop times to the stop time. A control device for an engine, wherein the control device is set as: The engine according to claim 1, wherein the idling stop control unit prohibits the idling stop when the trapping amount exceeds a first predetermined value that is a measure of an excessive temperature rise risk. 4. Control device . An exhaust gas temperature sensor for detecting at least one exhaust gas temperature on the upstream side and the downstream side of the processor,
When the exhaust gas temperature is equal to or lower than a first temperature set to a temperature at which the substance trapped in the processing device is started to be removed, the stop time is reduced and corrected as the exhaust gas temperature is lower. characterized by, an engine control apparatus according to any one of claims 1-3. Equipped with an intake air temperature sensor that detects intake air temperature,
The engine control device according to claim 4 , wherein, when the exhaust gas temperature is equal to or lower than the first temperature, the setting unit reduces and corrects the stop time as the intake air temperature is lower. The processor includes a trap catalyst capable of storing a sulfur component in exhaust gas,
The regeneration control unit performs S purge control for removing the sulfur component from the trap catalyst as the regeneration control,
The said idling stop control part prohibits the said idling stop , when the said idling stop conditions are fulfilled during the execution of the S purge control, The idling stop control is given in any 1 paragraph of Claims 1-5 characterized by the above-mentioned. Engine control device.

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