JP2010112189A - Pm regeneration processing system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the occurrence of oil dilution caused by performing PM regeneration processing by post-injection. <P>SOLUTION: This PM regeneration processing system has a means for acquiring the cylinder temperature and cylinder pressure of an internal combustion engine, a means for acquiring a PM collection quantity in a PM filter, a fuel injection means capable of performing after-injection and the post-injection as the other sub-injection of main injection, and a means for performing the PM regeneration processing for removing PM from the PM filter by performing the post-injection. When the cylinder temperature is higher than the reference temperature and when the cylinder pressure is higher than reference pressure, the PM regeneration processing is performed when the PM collection quantity becomes more than a first reference quantity, but when the cylinder temperature is lower than the reference temperature and when the cylinder pressure is lower than the reference pressure, the PM regeneration processing is not performed when the PM collection quantity is a second reference quantity or less even if its quantity is more than the first reference quantity, and processing is performed for raising the cylinder temperature and the cylinder pressure by increasingly correcting a main injection quantity or an after-injection quantity. When the PM collection quantity exceeds the second reference quantity, the PM regeneration processing is forcibly performed regardless of the cylinder temperature and the cylinder pressure. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a PM regeneration processing system for controlling execution of a PM regeneration process for removing particulate matter deposited on a PM filter provided in an exhaust system of an internal combustion engine from the PM filter.

  A technique is known in which a PM regeneration process is performed in which the particulate matter collected by the PM filter is removed from the PM filter by performing post injection, which is sub-injection performed after the main injection.

Patent Document 1 describes a technique for executing a PM regeneration process by post injection when the in-cylinder temperature of an internal combustion engine is equal to or higher than a predetermined temperature and the amount of collected PM is equal to or higher than a first predetermined amount.

In Patent Document 2, when the oil dilution rate detected during the PM regeneration process is equal to or higher than the limit oil dilution rate, NO ₂ is supplied to the PM filter, so that the particulate matter collected in the PM filter is reduced. A technique for suppressing dilution of engine oil with oxidized and post-injected fuel is described.

According to Patent Document 3, when the amount of particulate matter accumulated in the PM filter exceeds a predetermined value, fuel is supplied to the oxidation catalyst by sub-injection after the main injection, the PM filter inflow exhaust gas temperature is increased, and particulate matter is removed by combustion. The technology to do is described.

In Patent Document 4, when the particulate matter of the PM filter is burned and removed by a temperature raising operation such as post-injection, the time ratio of performing / stopping the temperature raising operation is changed according to the temperature of the PM filter. A technique for controlling the temperature of the filter near the target temperature is described.
JP 2008-38659 A JP 2006-183563 A Japanese Patent Laid-Open No. 2005-48663 JP 2004-301013 A

  When post-injection is performed when the in-cylinder temperature of the internal combustion engine is low, the post-injected fuel is difficult to evaporate in the cylinder, so that the penetration force of the fuel droplets is not weakened and easily collides with the cylinder wall. Therefore, there is a possibility that oil dilution occurs. Even when the in-cylinder pressure of the internal combustion engine is low, oil dilution may occur when post injection is performed.

  The present invention has been made in view of such problems. In a PM regeneration processing system of an internal combustion engine that includes a PM filter and performs PM regeneration processing by post-injection, the post-injection for PM regeneration processing is performed. It is an object to provide a technique capable of suppressing the occurrence of oil dilution due to this.

In order to achieve the above object, a PM regeneration processing system for an internal combustion engine of the present invention includes:
A PM filter provided in the exhaust passage of the internal combustion engine for collecting particulate matter in the exhaust;
In-cylinder temperature acquisition means for acquiring the in-cylinder temperature of the internal combustion engine by measurement or estimation;
PM collection amount acquisition means for acquiring the collection amount of particulate matter in the PM filter;
Fuel injection means capable of performing after injection, which is sub-injection performed immediately after main injection, and post-injection, which is sub-injection performed after after injection;
PM regeneration means for performing PM regeneration processing for removing the particulate matter collected by the PM filter from the PM filter by performing post injection by the fuel injection means;
When the amount of collected PM acquired by the PM collection amount acquisition unit is greater than a predetermined first reference amount, the PM is obtained if the in-cylinder temperature acquired by the in-cylinder temperature acquisition unit is equal to or higher than a predetermined reference temperature. The in-cylinder temperature when the PM regeneration processing by the regeneration means is executed and the PM collection amount acquired by the PM collection amount acquisition means is larger than a predetermined second reference amount that is larger than the first reference amount. PM regeneration control means for forcibly executing PM regeneration processing by the PM regeneration means regardless of the in-cylinder temperature obtained by the obtaining means;
In the internal combustion engine PM regeneration processing system equipped with
The PM regeneration control means is acquired by the in-cylinder temperature acquisition means when the PM collection amount acquired by the PM collection amount acquisition means is larger than the first reference amount and not more than the second reference amount. When the in-cylinder temperature is lower than the reference temperature, the PM regeneration process by the PM regeneration means is not executed, and the in-cylinder temperature is set to be equal to or higher than the reference temperature by correcting the injection amount by main injection or after injection. An in-cylinder temperature rise control is executed to calculate an increase correction amount for the injection amount necessary for raising the temperature to the temperature, and to increase the injection amount by main injection or after injection by the calculated increase correction amount. And

Here, the first reference amount is a reference value of the collection amount for determining whether it is necessary to remove the particulate matter collected by the PM filter by performing the PM regeneration process, and is determined in advance. .

In addition, if the particulate matter is collected in the PM filter beyond the second reference amount, the fuel efficiency deteriorates due to an increase in the back pressure in the exhaust passage, and the PM filter deteriorates due to excessive temperature rise during PM regeneration processing. The collected amount that can be determined to be a concern, and is a value that is larger than the first reference amount.

  When compared with the second reference amount, the first reference amount is preferably removed by the PM regeneration process to remove the collected particulate matter, but even if the particulate matter is collected by the PM filter beyond this, This is a collection amount with a collection margin that does not reach a situation such as an increase in back pressure or an excessive temperature rise of the PM filter during PM regeneration processing.

  The reference temperature, which is the reference value for the in-cylinder temperature, is the in-cylinder temperature at which it can be determined that there is no risk of post-injection fuel evaporating and diffusing properly in the cylinder and oil dilution. It is determined based on the lower limit value.

  In the present invention, the in-cylinder temperature acquisition means may acquire the in-cylinder temperature by direct measurement using a sensor, an intake pressure, an intake air temperature, an injection amount command value, a nozzle of a variable nozzle type turbocharger. The in-cylinder temperature may be acquired by estimation calculation based on various operating parameters such as the opening degree.

  When the in-cylinder temperature is lower than the reference temperature, the fuel injected into the cylinder by post injection is difficult to evaporate and diffuse, and oil dilution is likely to occur due to the execution of post injection. According to the PM regeneration processing system of the present invention, the trapped amount is the first reference amount under the low temperature in-cylinder condition where oil dilution may occur due to the execution of post injection for such PM regeneration processing. However, if the second reference amount is not exceeded, PM regeneration processing by post injection is not performed. Then, on the condition that the in-cylinder temperature is equal to or higher than the reference temperature or the in-cylinder temperature has risen to a temperature equal to or higher than the reference temperature, the PM regeneration process by post injection is started. Accordingly, it is possible to suppress the occurrence of oil dilution due to post injection in a low temperature cylinder.

In the PM regeneration processing system of the present invention, when the in-cylinder temperature is lower than the reference temperature, in-cylinder temperature increase control is performed to increase the in-cylinder temperature by correcting the amount of main injection or after injection to be increased. . This amount of increase correction is based on the difference between the current in-cylinder temperature acquired by the in-cylinder temperature acquisition means and the reference temperature, and the in-cylinder temperature is adjusted to the reference temperature by increasing the injection amount of the main injection or after injection. It is calculated as an increase correction amount for the injection amount necessary for raising the temperature to the above temperature.

  The relationship between the temperature difference between the in-cylinder temperature and the reference temperature and the increase correction amount for the injection amount may be mapped in advance by experiments or calculations. If the minimum required injection amount increase correction is performed for the temperature difference, an increase in fuel consumption accompanying the execution of the in-cylinder temperature increase control can be suppressed.

  According to the PM regeneration processing system of the present invention, when the in-cylinder temperature is lower than the reference temperature, control for increasing the in-cylinder temperature is executed, so that the cylinder that can perform post injection at an early stage without the risk of oil dilution. An internal temperature environment can be realized. This makes it possible to execute PM regeneration processing by post injection at an early stage. When the main injection amount is increased in executing the in-cylinder temperature rise control, it is preferable to simultaneously perform torque reduction processing such as throttle of the intake throttle valve in order to correct the deviation from the target torque.

According to the PM regeneration processing system of the present invention, when the in-cylinder temperature is lower than the reference temperature, the PM regeneration is performed until the in-cylinder temperature becomes equal to or higher than the reference temperature even if the collected amount exceeds the first reference amount. Execution of the process will be delayed, but if the collected amount exceeds the second reference amount, the PM regeneration process delay will be canceled and the PM regeneration process will be forced regardless of the in-cylinder temperature. Executed. This prevents the back pressure from excessively rising due to excessive collection of particulate matter in the PM filter, and prevents the PM filter from deteriorating due to excessive temperature rise of the PM filter during subsequent PM regeneration processing. it can.

  In the PM regeneration processing system of the present invention described above, the possibility of oil dilution due to post injection is determined based on a comparison between the in-cylinder temperature and a reference temperature, and post injection is performed based on the determination result and the collected amount. Although the technical idea for determining whether or not to execute the PM regeneration process by the above has been described, this technical idea can also be applied to the in-cylinder pressure. That is, the possibility of oil dilution by post injection is determined based on the comparison between the in-cylinder pressure and the reference pressure, and whether or not PM regeneration processing by post injection is to be executed is determined based on the determination result and the collected amount. You may do it.

In that case, the PM regeneration processing system of the present invention is
A PM filter provided in the exhaust passage of the internal combustion engine for collecting particulate matter in the exhaust;
In-cylinder pressure acquisition means for acquiring in-cylinder pressure of the internal combustion engine by measurement or estimation;
PM collection amount acquisition means for acquiring the collection amount of particulate matter in the PM filter;
Fuel injection means capable of performing after injection, which is sub-injection performed immediately after main injection, and post-injection, which is sub-injection performed after after injection;
PM regeneration means for performing PM regeneration processing for removing the particulate matter collected by the PM filter from the PM filter by performing post injection by the fuel injection means;
When the amount of collected PM acquired by the PM collection amount acquisition unit is greater than a predetermined first reference amount, the PM is obtained if the in-cylinder pressure acquired by the in-cylinder pressure acquisition unit is equal to or greater than a predetermined reference pressure. If the PM collection amount acquired by the PM collection amount acquisition unit is greater than a predetermined second reference amount that is greater than the first reference amount, the in-cylinder pressure is executed. PM regeneration control means for forcibly executing PM regeneration processing by the PM regeneration means regardless of the in-cylinder pressure obtained by the obtaining means;
An internal combustion engine PM regeneration processing system comprising:
The PM regeneration control means is acquired by the in-cylinder pressure acquisition means when the PM collection amount acquired by the PM collection amount acquisition means is larger than the first reference amount and not more than the second reference amount. When the in-cylinder pressure is lower than the reference pressure, the PM regeneration process by the PM regeneration means is not executed, and the in-cylinder pressure is set to be equal to or higher than the reference pressure by correcting the injection amount by main injection or after injection. An in-cylinder pressure increase control is executed to calculate an increase correction amount of the injection amount necessary for increasing the pressure, and to increase the injection amount by main injection or after injection by the calculated increase correction amount. And

  In this configuration, the reference pressure, which is the reference value of the in-cylinder pressure, is a cylinder that can be determined that post-injection fuel is suitably evaporated and diffused in the cylinder and there is no risk of oil dilution when post-injection is performed. It is determined based on the lower limit value of the internal pressure.

  In the present invention, the in-cylinder pressure acquisition means may acquire the in-cylinder pressure by direct measurement using a sensor, or the intake pressure, intake air temperature, injection amount command value, variable nozzle type turbocharger nozzle The in-cylinder pressure may be acquired by estimation calculation based on various operation parameters such as an opening degree.

  When the in-cylinder pressure is lower than the reference pressure, the fuel injected into the cylinder by post injection is difficult to evaporate and diffuse, and oil dilution is likely to occur due to execution of post injection. According to the PM regeneration processing system of the present invention, the trapped amount is the first reference amount under in-cylinder low pressure conditions where oil dilution may occur due to execution of post injection for such PM regeneration processing. However, if the second reference amount is not exceeded, PM regeneration processing by post injection is not performed. Then, on the condition that the in-cylinder pressure is equal to or higher than the reference pressure or the in-cylinder pressure is increased to a pressure equal to or higher than the reference pressure, the PM regeneration process by the post injection is executed. Therefore, it is possible to suppress the occurrence of oil dilution due to post injection in the low pressure cylinder.

  In the PM regeneration processing system of the present invention, when the in-cylinder pressure is lower than the reference pressure, in-cylinder pressure increase control for increasing the in-cylinder pressure is performed by increasing the amount of injection of main injection or after injection. . This increase correction amount is obtained by correcting the in-cylinder pressure to the reference pressure by correcting the main injection or after injection injection amount based on the difference between the current in-cylinder pressure acquired by the in-cylinder pressure acquisition means and the reference pressure. It is calculated as an increase correction amount for the injection amount required to increase the pressure to the above pressure.

  The relationship between the pressure difference between the in-cylinder pressure and the reference pressure and the increase correction amount for the injection amount may be mapped in advance by experiments or calculations. If the minimum required injection amount increase correction is performed for the pressure difference, an increase in fuel consumption accompanying the execution of the in-cylinder pressure increase control can be suppressed.

  According to the PM regeneration processing system of the present invention, when the in-cylinder pressure is lower than the reference pressure, the control for increasing the in-cylinder pressure is executed. Therefore, the cylinder that can perform post injection without risk of oil dilution at an early stage. An internal pressure environment can be realized. This makes it possible to execute PM regeneration processing by post injection at an early stage. When the main injection amount is increased in executing the in-cylinder pressure increase control, it is preferable to simultaneously perform torque reduction processing such as throttle of the intake throttle valve in order to correct the deviation from the target torque.

According to the PM regeneration processing system of the present invention, when the in-cylinder pressure is lower than the reference pressure, the PM regeneration is performed until the in-cylinder pressure becomes equal to or higher than the reference pressure even if the collected amount exceeds the first reference amount. Execution of the processing will be delayed, but if the collected amount exceeds the second reference amount, the PM regeneration processing execution delay is canceled and the PM regeneration processing is forcibly performed regardless of the in-cylinder pressure. Executed. This prevents the back pressure from excessively rising due to excessive collection of particulate matter in the PM filter, and prevents the PM filter from deteriorating due to excessive temperature rise of the PM filter during subsequent PM regeneration processing. it can.

  In addition, both the in-cylinder temperature and the in-cylinder pressure are acquired, the possibility of oil dilution by post injection is determined based on both the in-cylinder temperature and the in-cylinder pressure, and based on the determination result and the collected amount Thus, it may be determined whether or not to execute the PM regeneration process by post injection.

  According to the present invention, in a PM regeneration processing system of an internal combustion engine that includes a PM filter and performs PM regeneration processing by post-injection, suppressing occurrence of oil dilution due to execution of post-injection for PM regeneration processing Is possible.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the present embodiment are not intended to limit the technical scope of the invention only to those unless otherwise specified.

  FIG. 1 is a conceptual diagram schematically showing a schematic configuration of a diesel engine to which the PM regeneration processing system for an internal combustion engine according to this embodiment is applied, and an intake system and an exhaust system thereof.

The engine 1 is a diesel engine having four cylinders 4. Each cylinder 4 is provided with a fuel injection valve 10 for directly injecting fuel into the cylinder. The fuel injection valve 10 performs a plurality of fuel injections of a main injection that is a main fuel injection, an after injection that is a sub-injection performed immediately after the main injection, and a post-injection that is a sub-injection performed after the after injection. It can be executed in one cycle. The fuel injection valve 10 is connected to an engine control computer ECU 16 described later, and the fuel injection valve 10
The fuel injection by is controlled by the ECU 16.

Each cylinder 4 of the engine 1 communicates with an intake manifold 17 via an intake port that is opened and closed by an intake valve (not shown). The intake manifold 17 is connected to the intake passage 2. A throttle valve 9 is provided in the intake passage 2. A compressor 11 of a variable displacement turbocharger 13 is provided upstream of the throttle valve 9. The intake manifold 17 is provided with an intake pressure sensor 31 for measuring the intake pressure. Measurement data from the intake pressure sensor 31 is input to the ECU 16.

Each cylinder 4 of the engine 1 communicates with an exhaust manifold 18 via an exhaust port that is opened and closed by an exhaust valve (not shown). The exhaust manifold 18 is connected to the exhaust passage 3. The exhaust passage 3 is provided with a turbine 12 of a turbocharger 13. The turbocharger 13 is a variable displacement type, and is provided with a variable nozzle vane 30 that makes the exhaust flow rate characteristics of the turbine 12 variable. The variable nozzle vane 30 is connected to the ECU 16 and its opening degree is controlled by the ECU 16. A PM filter 8 is provided downstream of the turbine 12. The PM filter 8 is a filter that collects particulate matter in the inflowing exhaust gas.

The engine 1 is provided with an ECU 16 that is a computer for controlling the operating state of the engine 1. In addition to the intake pressure sensor 31 described above, the ECU 16 is connected to various sensors such as an in-cylinder pressure sensor 32 that measures the in-cylinder pressure of the cylinder 4 and an in-cylinder temperature sensor 33 that measures the in-cylinder temperature of the cylinder 4. Measurement data from various sensors is input to the ECU 16. In addition to measuring the in-cylinder temperature and the in-cylinder pressure with the in-cylinder temperature sensor 33 and the in-cylinder pressure sensor 32, the intake pressure measured by the intake pressure sensor 31, the injection amount command value to the fuel injection valve 10, the variable nozzle vane 30 The ECU 16 may calculate and obtain it based on various operation control information such as the opening degree of the engine and the intake air temperature measured by an intake air temperature sensor (not shown). The ECU 16 is connected to various devices such as the throttle valve 9, the variable nozzle vane 30, and the fuel injection valve 10 described above, and signals that control the operation of these various devices are output from the ECU 16.

In the PM regeneration processing system of the present embodiment, as the PM regeneration processing for removing the particulate matter collected by the PM filter 8 from the PM filter 8, the fuel injection valve 10 performs post injection and is collected by the PM filter 8. The temperature of the PM filter 8 is increased to a temperature range where the particulate matter can be oxidized. Other methods for removing the particulate matter collected by the PM filter 8 from the PM filter 8 may be used in combination, but in this embodiment, the PM regeneration process by the post injection will be particularly described.

FIG. 2 shows a flow of PM regeneration processing in the PM regeneration processing system of the present embodiment. The control routine represented by this flow is repeatedly executed by the ECU 16 with a predetermined feeling.

In step S11, the ECU 16 determines whether or not the amount of particulate matter collected in the PM filter 8 exceeds a predetermined first reference amount. The amount of particulate matter collected in the PM filter 8 can be obtained by various known methods. For example, the method of converting the elapsed time from the previous PM regeneration process to the collected amount, the method of converting the vehicle travel distance from the previous PM regeneration process to the collected amount, This is a method of integrating the amount of particulate matter discharged from the previous execution of the PM regeneration process to the present time. The first reference amount is a reference value of the collection amount for determining whether it is necessary to remove the particulate matter collected by the PM filter 8 by performing the PM regeneration process. Is stored in the ROM.

If it is determined in step S11 that the collected amount exceeds the first reference amount (Yes), the ECU 16 proceeds to step S12. On the other hand, when it is determined in step S11 that the collected amount is equal to or less than the first reference amount (No), the ECU 16 exits this routine.

In step S12, the ECU 16 provisionally determines execution of the PM regeneration process, and acquires the in-cylinder temperature T and the in-cylinder pressure P at the post-injection injection timing executed in the PM regeneration process. In this embodiment, the in-cylinder temperature T and the in-cylinder pressure P are acquired based on the measurement data from the in-cylinder temperature sensor 33 and the in-cylinder pressure sensor 32. As described above, these values may be obtained by an estimation calculation based on operation parameters.

In step S13, the ECU 16 determines whether or not the in-cylinder temperature T acquired in step S12 is equal to or higher than the reference temperature Tc, and whether or not the in-cylinder pressure P acquired in step S12 is equal to or higher than the reference pressure Pc. To do. The reference temperature Tc is determined based on the lower limit value of the in-cylinder temperature at which oil dilution is unlikely to occur even when post injection is performed. That is, if post injection is performed when the in-cylinder temperature T is lower than the reference temperature Tc, it can be determined that the post-injected fuel is less likely to evaporate and diffuse and oil dilution may occur. The reference pressure Pc is determined based on the lower limit value of the in-cylinder pressure that hardly causes oil dilution even when post injection is performed. That is, if post injection is performed when the in-cylinder pressure P is lower than the reference pressure Pc, it can be determined that the post-injected fuel is less likely to evaporate and diffuse and oil dilution may occur.

In step S13, the in-cylinder temperature T is equal to or higher than the reference temperature Tc, and the in-cylinder pressure P is the reference pressure Pc.
If it is determined that the above is true (Yes), the ECU 16 proceeds to step S14. If it is determined in step S13 that the in-cylinder temperature T is lower than the reference temperature Tc or the in-cylinder pressure P is lower than the reference pressure Pc (No), the ECU 16 proceeds to step S15.

In step S14, the ECU 16 shifts to execution of PM regeneration processing. That is, the fuel injection valve 10 is controlled to perform post injection. In this case, since the cylinder is in a high-temperature and high-pressure environment in which the post-injected fuel can be suitably evaporated and diffused, the PM filter 8 can be suitably heated and the collected particulate matter can be removed without causing oil dilution. Done.

  In step S15, the ECU 16 calculates a temperature difference ΔT between the in-cylinder temperature T acquired in step S12 and the reference temperature Tc.

In step S16, the ECU 16 increases the in-cylinder temperature by the temperature difference ΔT calculated in step S15 by correcting the main injection amount or the after injection amount by increasing the main injection amount or after injection. An amount increase correction amount is calculated, and the main injection amount or the after injection amount is increased and corrected by the calculated increase correction amount. The relationship between this temperature difference ΔT and the amount of increase correction required to raise the in-cylinder temperature by ΔT is previously investigated and mapped by experiments and stored in the ROM of the ECU 16. The in-cylinder temperature rises by increasing the main injection amount or the after injection amount.

  In step S17, the ECU 16 acquires the in-cylinder temperature T and the in-cylinder pressure P again, the newly acquired in-cylinder temperature T is equal to or higher than the reference temperature Tc, and the newly acquired in-cylinder pressure P is the reference pressure. It is determined whether or not it is greater than or equal to Pc. If it is determined in step S17 that the in-cylinder temperature T is equal to or higher than the reference temperature Tc and the in-cylinder pressure P is equal to or higher than the reference pressure Pc (Yes), the ECU 16 proceeds to step S18. On the other hand, if it is determined in step S17 that the in-cylinder temperature T is lower than the reference temperature Tc or the in-cylinder pressure P is lower than the reference pressure Pc (No), the ECU 16 proceeds to step S19.

In step S18, as in step S14, the ECU 16 causes the fuel injection valve 10 to perform post injection and shifts to the PM regeneration process. At this time, since the inside of the cylinder is in a high temperature and high pressure environment in which the post-injected fuel can be suitably evaporated and diffused, the PM filter 8 can be suitably heated and the collected particulate matter can be removed without causing oil dilution. Done.

In step S19, the ECU 16 acquires the collected amount of the particulate matter in the PM filter 8 again, and determines whether or not the newly acquired collected amount exceeds a predetermined second reference amount. The method for acquiring the amount of collected particulate matter in the PM filter 8 is as described in step S11. If the particulate matter is collected in the PM filter 8 beyond the second reference amount, the exhaust passage 2
The collected amount is such that there is a possibility that the fuel efficiency deteriorates due to an increase in the back pressure and the PM filter 8 deteriorates due to excessive temperature rise during PM regeneration processing, and is larger than the first reference amount. That is, the first reference amount preferably removes the collected particulate matter by PM regeneration treatment, but even if the particulate matter is collected in the PM filter 8 beyond this, the back pressure rise or PM The collection amount has a collection margin that does not reach a situation such as excessive temperature rise of the PM filter 8 during the regeneration process. If it is determined in step S19 that the collected amount exceeds the second reference amount (Yes), the ECU 16 proceeds to step S20. If it is determined in step S19 that the collected amount is equal to or smaller than the second reference amount (No), the ECU 16 returns to step S15.

In step S20, the ECU 16 causes the fuel injection valve 10 to perform post injection, and starts the PM regeneration process. In this case, as determined negative in step S17, the in-cylinder temperature T is lower than the reference temperature Tc, and the in-cylinder pressure P is lower than the reference pressure Pc, so that oil dilution may occur when post injection is performed. However, it is more certain that the PM filter 8 will deteriorate due to excessive temperature rise during the next PM regeneration process when the collected amount of particulate matter in the PM filter 8 exceeds the second reference amount. The PM regeneration process is forcibly executed regardless of the values of the in-cylinder temperature and the in-cylinder pressure.

On the other hand, if the amount of particulate matter collected by the PM filter 8 still does not exceed the second reference amount (step S19: No), the particulate matter further increases without the risk of increased back pressure and excessive temperature rise during PM regeneration processing. Since the in-cylinder environment becomes high temperature and high pressure to the extent that it is possible to more reliably suppress the occurrence of oil dilution due to the execution of post injection, repeat step S15 and subsequent steps. The cylinder temperature and the cylinder pressure are increased by increasing the main injection amount or the after injection amount.

  By executing the above routine, it is possible to suppress the occurrence of oil dilution due to the execution of post injection for PM regeneration processing.

In this embodiment, the in-cylinder temperature sensor 33 and the ECU 16 that acquires the in-cylinder temperature T in step S12 correspond to the in-cylinder temperature acquisition means in the present invention. The in-cylinder pressure sensor 32 and the ECU 16 that acquires the in-cylinder pressure P in step S12 correspond to the in-cylinder pressure acquisition means in the present invention. The ECU 16 that acquires the collection amount of the particulate matter in the PM filter 8 in step S11 and step S19 corresponds to the PM collection amount acquisition means in the present invention. The fuel injection valve 10 corresponds to the fuel injection means in the present invention. The ECU 16 that executes the processes of step S14, step S18, and step S20 corresponds to the PM reproducing means in the present invention. Step S11, Step S13, Step S17,
The ECU 16 that performs the determination process of step S19 and executes step S14 and other processes described above based on the determination result corresponds to the PM regeneration control means in the present invention.

When the pressure difference ΔP between the in-cylinder pressure P and the reference pressure Pc is calculated in step S15, and in the subsequent step S16, the in-cylinder pressure is increased by the pressure difference ΔP by increasing the main injection amount or the after injection amount. It is also possible to calculate the increase correction amount of the injection amount necessary for the correction, and to perform correction for increasing the main injection amount or the after injection amount by the calculated increase correction amount. Further, only one of the in-cylinder temperature or the in-cylinder pressure is acquired in Step S12, the acquired parameter is compared with the reference value in Step S13 and Step S17, and the acquired value and the reference are compared in Step S15 and Step S16. Calculate the injection amount increase correction amount corresponding to the difference from the value,
You may make it perform injection quantity increase correction.

It is a figure which shows schematic structure of the diesel engine which applies PM regeneration processing system of Example 1, and its intake system, exhaust system, and control system. 3 is a flowchart illustrating a control routine of the PM regeneration processing system according to the first embodiment.

Explanation of symbols

1 Engine 2 Intake Passage 3 Exhaust Passage 4 Cylinder 8 PM Filter 9 Throttle Valve 10 Fuel Injection Valve 11 Compressor 12 Turbine 13 Turbocharger 16 ECU
17 Intake cylinder 18 Exhaust manifold 30 Variable nozzle vane 31 Intake pressure sensor 32 In-cylinder pressure sensor 33 In-cylinder temperature sensor

Claims (2)

A PM filter provided in the exhaust passage of the internal combustion engine for collecting particulate matter in the exhaust;
In-cylinder temperature acquisition means for acquiring the in-cylinder temperature of the internal combustion engine by measurement or estimation;
PM collection amount acquisition means for acquiring the collection amount of particulate matter in the PM filter;
Fuel injection means capable of performing after injection, which is sub-injection performed immediately after main injection, and post-injection, which is sub-injection performed after after injection;
PM regeneration means for performing PM regeneration processing for removing the particulate matter collected by the PM filter from the PM filter by performing post injection by the fuel injection means;
When the amount of collected PM acquired by the PM collection amount acquisition unit is greater than a predetermined first reference amount, the PM is obtained if the in-cylinder temperature acquired by the in-cylinder temperature acquisition unit is equal to or higher than a predetermined reference temperature. The in-cylinder temperature when the PM regeneration processing by the regeneration means is executed and the PM collection amount acquired by the PM collection amount acquisition means is larger than a predetermined second reference amount that is larger than the first reference amount. PM regeneration control means for forcibly executing PM regeneration processing by the PM regeneration means regardless of the in-cylinder temperature obtained by the obtaining means;
An internal combustion engine PM regeneration processing system comprising:
The PM regeneration control means is acquired by the in-cylinder temperature acquisition means when the PM collection amount acquired by the PM collection amount acquisition means is larger than the first reference amount and not more than the second reference amount. When the in-cylinder temperature is lower than the reference temperature, the PM regeneration process by the PM regeneration means is not executed, and the in-cylinder temperature is set to be equal to or higher than the reference temperature by correcting the injection amount by main injection or after injection. An in-cylinder temperature rise control is executed to calculate an increase correction amount for the injection amount necessary for raising the temperature to the temperature, and to increase the injection amount by main injection or after injection by the calculated increase correction amount. PM regeneration processing system for internal combustion engines. A PM filter provided in the exhaust passage of the internal combustion engine for collecting particulate matter in the exhaust;
In-cylinder pressure acquisition means for acquiring in-cylinder pressure of the internal combustion engine by measurement or estimation;
PM collection amount acquisition means for acquiring the collection amount of particulate matter in the PM filter;
Fuel injection means capable of performing after injection, which is sub-injection performed immediately after main injection, and post-injection, which is sub-injection performed after after injection;
PM regeneration means for performing PM regeneration processing for removing the particulate matter collected by the PM filter from the PM filter by performing post injection by the fuel injection means;
When the amount of collected PM acquired by the PM collection amount acquisition unit is greater than a predetermined first reference amount, the PM is obtained if the in-cylinder pressure acquired by the in-cylinder pressure acquisition unit is equal to or greater than a predetermined reference pressure. If the PM collection amount acquired by the PM collection amount acquisition unit is greater than a predetermined second reference amount that is greater than the first reference amount, the in-cylinder pressure is executed. PM regeneration control means for forcibly executing PM regeneration processing by the PM regeneration means regardless of the in-cylinder pressure obtained by the obtaining means;
An internal combustion engine PM regeneration processing system comprising:
The PM regeneration control means is acquired by the in-cylinder pressure acquisition means when the PM collection amount acquired by the PM collection amount acquisition means is larger than the first reference amount and not more than the second reference amount. When the in-cylinder pressure is lower than the reference pressure, the PM regeneration process by the PM regeneration means is not executed, and the in-cylinder pressure is set to be equal to or higher than the reference pressure by correcting the injection amount by main injection or after injection. An in-cylinder pressure increase control is executed to calculate an increase correction amount of the injection amount necessary for increasing the pressure, and to increase the injection amount by main injection or after injection by the calculated increase correction amount. PM regeneration processing system for internal combustion engines.

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