JP2010223187A - Engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine control device for reducing a combustion sound when increasing request torque, and protecting a filter for collecting particulate matter. <P>SOLUTION: This engine control device 100 controls an engine 10 for injecting pressurized fuel in a pressure accumulating chamber 54 into a combustion chamber 15 by an injector 56, and includes a request torque detecting means 101 for detecting driver request torque, a particulate matter deposit quantity estimating means for arithmetically operating an estimated deposit quantity of the particulate matter to the filter 80 for capturing the particulate matter in exhaust gas, and a fuel pressure control means for executing pressure reduction control for reducing fuel pressure in the pressure accumulating chamber over a predetermined period in response to an increase in the request torque and prohibiting the pressure reduction control when the estimated deposit quantity of the particulate matter becomes a predetermined value or more. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine control device that controls fuel supply of an engine provided with a filter that captures particulate matter (PM) contained in exhaust gas.

In an engine with a turbocharger, when the accelerator is turned on from off, a response delay (turbo lag) occurs until the boost pressure is improved.
For this reason, in the case of a diesel engine or the like that adjusts the engine output mainly by the fuel injection amount, the fuel injection amount is increased before the boost pressure rises and the intake air amount increases. Emissions will increase, and noise will be generated due to changes in combustion conditions.

  In order to solve such a problem, for example, Patent Document 1 has a pressure accumulator that stores low-pressure and high-pressure fuel, and when there is an acceleration request from the driver, the high-pressure side in the fuel flow path An accumulator fuel injection device that delays the closing timing of a control valve provided downstream of the accumulator and upstream of the low pressure accumulator is described. According to this, by delaying the closing timing of the control valve, the fuel pressure in the low-pressure side accumulator is positively increased, and low-pressure injection suitable for the engine operating state is realized at an early stage.

JP 2000-154765 A

In the technique described in Patent Document 1, since two accumulators are required, the structure of the apparatus becomes complicated, the number of parts increases, and the assembly process becomes complicated.
Moreover, when the fuel pressure (fuel pressure) is lowered and injected when the driver requests acceleration as in this technology, combustion noise can be suppressed, but the emission of particulate matter in the exhaust gas increases, In order to prevent clogging of the diesel particulate filter (DPF) that collects the fuel, it is necessary to frequently perform the regeneration process. DPF regeneration is performed, for example, by raising the exhaust gas temperature using post-injection or the like and oxidizing particulate matter deposited on the filter. If this is done frequently, drivability and fuel efficiency will be impaired. There is a concern that the filter may be damaged by burning or the like. Further, if the control for reducing the fuel pressure is frequently performed, there is a concern that the amount of particulate matter deposited increases and the filter regeneration process cannot catch up.
In view of the above-described problems, an object of the present invention is to provide an engine control device that reduces combustion noise when a required torque is increased and protects a filter that collects particulate matter.

The present invention solves the above-described problems by the following means.
According to a first aspect of the present invention, there is provided an engine control device for controlling an engine for injecting pressurized fuel in a pressure accumulating chamber into a combustion chamber by an injector, the required torque detecting means for detecting a driver required torque, and particles in the exhaust gas. Particulate matter accumulation amount estimation means for calculating an estimated accumulation amount of the particulate matter on the filter that captures the particulate matter, and pressure reduction that lowers the fuel pressure in the pressure accumulating chamber over a predetermined period according to an increase in the required torque An engine control device comprising: a fuel pressure control unit that executes control and prohibits the pressure reduction control when the estimated accumulation amount of the particulate matter exceeds a predetermined value.

The invention according to claim 2 is characterized in that the fuel pressure control means sets an upper limit of the amount of decrease in the fuel pressure during the pressure reduction control based on the estimated deposition amount of the particulate matter. This is an engine control device.
According to a third aspect of the present invention, there is provided filter regeneration means for improving the exhaust gas temperature to perform regeneration of the filter, and the fuel pressure control means has completed the number of executions of the decompression control within a predetermined period or the latest regeneration process. 3. The engine control device according to claim 1, wherein the decompression control is executed only when the subsequent number of executions of the decompression control is less than a predetermined value. 4.
The invention according to claim 4 is characterized in that the particulate matter accumulation amount estimation means calculates the estimated accumulation amount using an integrated value of the accumulation amount increase amount accompanying execution of the decompression control. It is an engine control device given in any 1 paragraph to Claim 3.
The invention according to claim 5 is characterized in that the accumulation amount increase amount is calculated by correcting the particulate matter discharge basic amount during normal operation by an increase coefficient corresponding to the fuel pressure decrease amount in the decompression control. The engine control device according to claim 4.

According to the present invention, the following effects can be obtained.
(1) The pressure reduction control is performed to reduce the fuel pressure in the pressure accumulating chamber over a predetermined period in response to the increase in the required torque, and the pressure reduction control is prohibited when the estimated amount of particulate matter accumulated exceeds a predetermined value. Thus, it is possible to suppress the combustion noise by the pressure reduction control in the normal state, and to protect the filter by prioritizing the regeneration of the filter over the reduction of the combustion noise when the amount of accumulated particulate matter increases.
(2) By setting the upper limit of the amount of decrease in fuel pressure during pressure reduction control based on the amount of particulate matter deposited, appropriate pressure reduction control reflecting the state of the filter is performed, and filter protection and combustion noise reduction are achieved. Both can be achieved.
(3) The decompression control is frequently performed by executing the decompression control only when the number of executions of the decompression control within the predetermined period or the number of executions of the decompression control after completing the most recent regeneration process is less than the predetermined value. Therefore, it is possible to prevent the amount of accumulated particulate matter from increasing rapidly and impairing the function of the filter.
(4) By calculating the estimated accumulation amount by adding the accumulated value of the accumulation amount increase associated with the execution of the decompression control, it is possible to estimate an appropriate accumulation amount that reflects the execution of the decompression control. Good control can be done.
(5) The above-described increase in the amount of accumulation is calculated by correcting the basic discharge amount of particulate matter during normal operation with an increase coefficient corresponding to the amount of decrease in fuel pressure in the pressure reduction control, thereby allowing a relatively light calculation load. Accumulated deposition amount can be calculated with high accuracy.

It is a figure which shows the system configuration | structure of the diesel engine for vehicles containing the Example of the engine control apparatus to which this invention is applied. It is a flowchart which shows execution condition establishment judgment of the pressure reduction control at the time of transient in the engine control apparatus of FIG. It is a block diagram which shows the calculation method of the PM emission increase integrated amount in the engine control apparatus of FIG. It is a flowchart which shows the pressure reduction control at the time of a transition in the engine control apparatus of FIG. It is a block diagram which shows the calculation method of the fuel pressure fall amount of transient pressure reduction control in the engine control apparatus of FIG.

  It is an object of the present invention to provide an engine control device that reduces a combustion noise when a required torque is increased and protects a filter that collects particulate matter. The fuel pressure in transient pressure reduction control according to the amount of PM deposited on the DPF The problem was solved by setting an upper limit value for the amount of decrease and prohibiting pressure reduction control when the PM accumulation amount is greater than or equal to a predetermined value.

Embodiments of an engine control apparatus to which the present invention is applied will be described below.
FIG. 1 is a diagram illustrating a system configuration of a vehicular diesel engine including an engine control apparatus according to an embodiment.
The engine 10 includes a turbocharger 20, an intake system 30, an exhaust system 40, a fuel supply device 50, an EGR device 60, an oxidation catalyst (DOC) 70, a diesel particulate filter (DPF) 80, an engine control unit (ECU 100), and the like. Configured.

The engine 10 is, for example, a four-stroke diesel engine used as a driving power source for automobiles such as passenger cars.
The engine 10 includes a crankshaft 11, a piston 12, a cylinder block 13, a head 14, a combustion chamber 15, a glow plug 16, a glow controller 17, and the like.
The crankshaft 11 is an output shaft of the engine 10.
The piston 12 is a member that reciprocates in the cylinder and transmits the combustion pressure to the crankshaft 11 via the connecting rod.
The cylinder block 13 is formed integrally with a cylinder portion in which the piston 12 is accommodated and a crankcase portion in which the crankshaft 11 is rotatably supported.
The head 14 is provided at the crown-side end of the piston 12 of the cylinder block 13 and includes an intake port, an exhaust port, a valve drive mechanism that opens and closes the intake valve and the exhaust valve, and the like.
The combustion chamber 15 is formed between the crown surface of the piston 12 and the portion of the head 14 facing this.
The glow plug 16 is a preheating device provided in the head 14 with the tip portion exposed in the combustion chamber 15.
The glow controller 17 controls the energization amount to the glow plug 16 according to the control of the ECU 100.

The turbocharger 20 compresses combustion air (fresh air) taken in by the engine 10 using energy of exhaust gas (burned gas) of the engine 10.
The turbocharger 20 includes a compressor 21, a turbine 22, an actuator 23, a negative pressure control valve 24, and the like.
The compressor 21 is a centrifugal compressor that compresses combustion air.
The turbine 22 is provided coaxially with the compressor 21 and is driven by the exhaust gas of the engine 10 and drives the compressor 21. The turbine 22 is of a variable geometry type in which the geometry can be continuously changed by a movable vane provided in nozzles around the turbine wheel.
The actuator 23 is a negative pressure type actuator that drives a movable vane of the turbine 22.
The negative pressure control valve 24 is an electromagnetic valve that introduces a negative pressure from a negative pressure source (not shown) into the actuator 23 according to the control of the ECU 100.

The intake system 30 introduces combustion air into the engine 10.
The intake system 30 includes an intake duct 31, an air cleaner 32, an air flow meter 33, an intercooler 34, a throttle valve 35, an actuator 36, an intake chamber 37, an intake pressure sensor 38, an intake manifold 39, and the like.

The intake duct 31 is an air flow path that introduces combustion air from the atmosphere and supplies it to the engine 10 via the compressor 21 of the turbocharger 20.
The air cleaner 32 includes a filter element that filters air to remove dust and the like. The air that has passed through the air cleaner 32 is introduced into the compressor 21 of the turbocharger 20 and compressed.
The air flow meter 33 is provided at the outlet of the air cleaner 32 and includes a sensor that detects the air flow rate. The air flow meter 33 includes an intake air temperature sensor for detecting the intake air temperature.

The intercooler 34 is a heat exchanger that cools the air that has exited the compressor 21 of the turbocharger 20 by heat exchange with the traveling wind.
The throttle valve 35 is provided on the downstream side of the intercooler 34 and adjusts the intake air amount of the engine 10.
The actuator 36 opens and closes the throttle valve 35 in response to a control signal from the ECU 100.
The intake chamber 37 is an air chamber into which air that has passed through the throttle valve 35 is introduced, and is connected to an intake port of the engine 10 via an intake manifold 39.
The intake pressure sensor 38 is provided in the intake chamber 37 and detects a pressure in the intake chamber 37 substantially equal to the intake pressure of the engine 10.
The intake manifold 39 is a branch pipe that introduces air from the intake chamber 37 to the intake port of each cylinder of the engine 10.

The exhaust system 40 includes an exhaust manifold 41, an exhaust pipe 42, and the like.
The exhaust manifold 41 is a pipe line that collects exhaust gas discharged from the exhaust port of each cylinder of the engine 10 and introduces the exhaust gas into the turbine 22 of the turbocharger 20.
The exhaust pipe 42 is a pipe line that discharges the exhaust discharged from the turbine 22 to the outside of the vehicle. The exhaust pipe 42 is provided with an exhaust gas aftertreatment device such as a DOC 70 and a DPF 80.

  The fuel supply device 50 supplies fuel into the combustion chamber 15 of the engine 10. The fuel supply device 50 is a common rail type high pressure fuel injection device including a supply pump 51, a suction metering solenoid valve 52, a fuel temperature sensor 53, a common rail 54, a fuel pressure sensor 55, an injector 56, and the like.

The supply pump 51 includes, for example, an inner cam type pressure feeding system, and pressurizes light oil as fuel and supplies it to the common rail 54.
The intake metering solenoid valve 52 adjusts the fuel intake amount of the supply pump 51 and is driven according to a control signal from the ECU 100.
The fuel temperature sensor 53 detects the temperature of the fuel in the supply pump 51.

The common rail 54 is a pressure accumulator that stores high-pressure fuel discharged from the supply pump 51.
The fuel pressure sensor 55 detects the fuel pressure (fuel pressure) in the common rail 54. The above-mentioned intake metering solenoid valve 52 is adjusted in its opening degree by feedback control using the output of the fuel pressure sensor 55 so that the fuel pressure becomes a predetermined target value set according to, for example, the engine speed and load. The
The injector 56 injects fuel supplied from the common rail 54 into the combustion chamber 15 of each cylinder. The injector 56 has a valve body that is opened and closed by an actuator such as a piezo element or a solenoid, and is opened in response to an injection pulse signal from the ECU 100. The injection timing and injection amount of the injector 56 are controlled by the ECU 100.

The EGR device 60 is intended to recirculate a part of the exhaust gas of the engine 10 extracted from the exhaust manifold 41 into the intake duct 31 for the purpose of reducing the NOx emission amount by suppressing the combustion temperature.
The EGR device 60 includes an EGR passage 61, an EGR control valve 62, an EGR cooler 63, and the like.
The EGR passage 61 is a conduit for introducing exhaust gas from the exhaust manifold 41 to the intake duct 31.
The EGR control valve 62 adjusts the exhaust gas flow rate (EGR amount) of the EGR passage 61 according to the control of the ECU 100.
The EGR cooler 63 cools the exhaust gas flowing through the EGR passage 61 by heat exchange with the traveling wind.

The DOC 70 is provided in the exhaust pipe 42 and mainly oxidizes hydrocarbons (HC) in the exhaust gas. The DOC 70 is formed by supporting a noble metal such as platinum or palladium or a metal oxide such as alumina on the surface of a ceramic carrier such as a cordierite honeycomb structure.
The DOC 70 is provided with a temperature sensor 71 for detecting the exhaust gas temperature at the inlet portion.

The DPF 80 is provided on the downstream side of the DOC 70 of the exhaust pipe 42 and includes a filter that collects particulate matter (PM) by filtering the exhaust gas. Here, PM includes soot (soot), organic solvent soluble components (SOF), sulfate (SO ₄ ), and the like.
For example, the filter is formed by forming heat resistant ceramics such as cordierite in a honeycomb structure, and sealing a large number of cells serving as gas flow paths at the end face so that the inlet side and the outlet side are staggered. Wall flow type.
The DPF 80 includes a differential pressure sensor 81 that detects a differential pressure between the inlet pressure and the outlet pressure, and a temperature sensor 82 that detects the exhaust gas temperature at the outlet.

The ECU 100 controls the above-described engine 10 and its auxiliary devices in an integrated manner, and includes an information processing device such as a CPU, a storage device such as a ROM and a RAM, an input / output interface, an A / D converter, Peripheral circuits such as timers, counters and various logic circuits are provided.
In addition to the various sensors described above, the outputs of the accelerator pedal sensor 101 and the atmospheric pressure sensor 102 are input to the ECU 100.
The accelerator pedal sensor 101 is request torque detection means for detecting driver request torque by detecting the position of the accelerator pedal operated by the driver.
The atmospheric pressure sensor 102 detects atmospheric pressure in the ambient atmosphere of the vehicle.

The ECU 100 controls the opening degree of the throttle valve 35, the fuel injection amount and timing of the fuel supply device 50, the fuel pressure, and the like according to the required torque set according to the output of the accelerator pedal sensor 101.
The ECU 100 also has a function of performing DPF regeneration control and transient pressure reduction control described below.

In the DPF regeneration control, when the amount of PM deposited on the DPF 80 increases, the exhaust gas temperature is improved, the PM deposited on the filter is oxidized at a high temperature, and the filter is regenerated. The exhaust gas temperature is improved by performing post injection in the latter stage of the expansion stroke in the engine 10 to introduce a part of the fuel into the exhaust pipe 42 without being burned, and to oxidize (combust) it with the DOC 70 or the like. The DPF regeneration control is executed when a predetermined time has elapsed from the previous DPF regeneration control and the estimated accumulation amount of PM is greater than or equal to a predetermined value. At this time, the ECU 100 functions as a filter regeneration means according to the present invention.
For example, a map of PM emissions based on the engine speed and fuel injection amount is prepared in advance by experiment or simulation, and the PM accumulation amount sequentially obtained based on this map is integrated to obtain the estimated PM accumulation amount. Can be sought.

The transient decompression control is performed when the driver requested torque is larger than the actual torque generated by the engine 10 and a predetermined transient decompression control execution condition is satisfied, for example, immediately after the driver depresses the accelerator pedal. The internal combustion pressure is lowered to lower the injection pressure from the injector 56, and the combustion noise of the engine 10 is reduced. At this time, the ECU 100 functions as fuel pressure control means in the present invention.
In the present embodiment, the PM emission increase integrated amount (estimated accumulation amount referred to in the present invention) by the transient pressure reduction control is calculated, and the transient pressure reduction control is executed only when this is equal to or less than a predetermined value. This will be described in detail below.

FIG. 2 is a flowchart showing determination of execution conditions for transient pressure reduction control. Hereinafter, the steps will be described step by step.
<Step S01: Judgment of upper limit number of executions in driving cycle>
The ECU 100 determines whether or not the number of executions of the transient pressure reduction control within one driving cycle (from the start to the stop of the engine 10) is within a preset upper limit number of times, and if it is within the upper limit number of times, step S02. If the upper limit number of executions has been exceeded, the process proceeds to step S06.

<Step S02: Determination of Upper Limit Execution Count from Completion of DPF Regeneration>
The ECU 100 determines whether the number of executions of the transient pressure reduction control after completion of the DPF regeneration control performed last time is within a preset upper limit number of times, and if it is within the upper limit number of times, the process proceeds to step S03. If the upper limit number of executions has been exceeded, the process proceeds to step S06.

<Step S03: PM emission increase integrated amount calculation>
The ECU 100 calculates a PM emission increase integrated amount that is an estimated integrated value of the PM accumulation amount increased with respect to the normal operation state by executing the transient pressure reduction control. At this time, the ECU 100 functions as the particulate matter accumulation amount estimation means referred to in the present invention.
FIG. 3 is a block diagram showing a method for calculating the PM emission increase integrated amount.
The PM emission increase amount is obtained by multiplying the PM emission increase basic amount read from the two-dimensional map based on the engine speed and the fuel injection amount by the PM increase coefficient set based on the common rail pressure subtraction amount. Calculated. The PM increase coefficient is set to a larger value as the common rail pressure subtraction amount is larger. The PM emission increase basic amount and the PM increase coefficient are stored in advance as a database such as a map. The PM emission increase integrated amount is calculated by integrating the sequentially calculated PM emission increase amount.
Thereafter, the process proceeds to step S04.

<Step S04: PM emission increase integrated amount judgment>
The ECU 100 determines whether the PM emission increase integrated amount calculated in step S03 is less than a predetermined value set in advance, and if it is less than the predetermined value, the process proceeds to step S05. On the other hand, when the PM emission increase integrated amount is not less than the predetermined value, the process proceeds to step S06.

<Step S05: Satisfaction Conditions for Transition Pressure Reduction>
The ECU 100 turns on the transient pressure reduction control execution condition flag, assuming that the transient pressure reduction control execution condition is satisfied, and ends (returns) a series of processes.

<Step S06: Conditions for executing pressure reduction control during transient are not satisfied>
ECU 100 assumes that the transient pressure reduction control execution condition is not satisfied, turns off the transient pressure reduction control execution condition flag, and ends (returns) a series of processes. At this time, the transient pressure reduction control is prohibited regardless of whether other conditions are satisfied.

FIG. 4 is a flowchart showing the transient pressure reduction control in this embodiment. Hereinafter, the steps will be described step by step.
<Step S11: Transient condition determination>
The ECU 100 compares the driver request torque set according to the output of the accelerator pedal sensor 101 with the value obtained by adding the predetermined value α to the estimated actual torque of the engine 10, and if the former is larger than the latter, Since the response delay of the supply pressure has occurred and the engine 10 is in a transient state (transitional state determination is established), the process proceeds to step S12. On the other hand, if the former is equal to or less than the latter, it is determined that the engine 10 is in a steady state (transient state determination is not established) and the process proceeds to step S16.

<Step S12: Transient pressure reduction control execution condition determination>
The ECU 100 checks the state of the transient pressure reduction control execution condition flag described above, and proceeds to step S13 if the flag is on, and proceeds to step S16 if the flag is off.

<Step S13: Execution of transient pressure reduction control>
The ECU 100 executes transient pressure reduction control for reducing the fuel pressure in the common rail 54 by a common rail pressure subtraction amount described below.
FIG. 5 is a block diagram illustrating a method for calculating the common rail pressure subtraction amount.
The common rail pressure subtraction amount is a value obtained by correcting the common rail pressure subtraction basic amount read from the two-dimensional map based on the engine speed and the fuel injection amount based on the differential pressure between the target intake pressure and the actual intake pressure, The larger one of the common rail pressure subtraction maximum values set based on the PM accumulation amount of the DPF 80 is used. The maximum value of the common rail pressure subtraction amount is set so as to decrease as the PM accumulation amount increases. Here, the target intake pressure is calculated according to the driver request torque, and the actual intake pressure is detected based on the output of the intake pressure sensor 38. Further, the PM accumulation amount is detected based on the output of the differential pressure sensor 81 of the DPF 80.
Thereafter, the process proceeds to step S14.

<Step S14: Judgment of execution time>
The ECU 100 compares the elapsed time (execution time) from the start of the current transient pressure reduction control with a preset upper limit time. If the elapsed time is less than or equal to the upper limit time, the ECU 100 proceeds to step S15. If the upper limit time is exceeded, the process proceeds to step S16.

<Step S15: Determination of execution condition / transient condition determination>
The ECU 100 determines whether the above-described transient pressure reduction control execution condition and transient state determination are satisfied, and if both are satisfied, the process returns to step S13 and the subsequent processing is repeated. On the other hand, if either one or both are not established, the process proceeds to step S16.

<Step S16: Stop pressure reduction during transition>
The ECU 100 stops transient pressure reduction control, counts up the number of times of transient pressure reduction control execution, and ends (returns) a series of processes.

According to the present embodiment described above, the following effects can be obtained.
(1) It is necessary to execute the pressure reduction control during transient to reduce the fuel pressure in the common rail 54 in accordance with the increase in the driver request torque, and to regenerate the DPF 80 when the PM emission increase integrated amount exceeds a predetermined value. By determining that the pressure is reduced and prohibiting transient pressure reduction control, the regeneration of the DPF 80 is prioritized over the reduction of combustion noise, and the filter can be protected.
(2) By setting the upper limit of the common rail pressure subtraction amount at the time of transient pressure reduction control based on the accumulation amount of PM, appropriate transient pressure reduction control reflecting the state of the DPF 80 is performed, filter protection and combustion noise reduction, Can be made compatible.
(3) Transient pressure reduction control is executed only when the number of times of transient pressure reduction control within one driving cycle or the number of times of transient pressure reduction control after the most recent DPF regeneration control is less than a predetermined value. It can be prevented that the time pressure reduction control is frequently performed and the PM emission amount increases rapidly and the function of the DPF 80 is impaired.
(4) Estimating an appropriate accumulation amount that reflects the execution of the pressure reduction control by determining the execution condition of the pressure reduction control during the transition using the integrated value of the PM emission increase amount accompanying the execution of the pressure reduction control during the transient. Therefore, accurate control can be performed.
(5) The PM emission increase amount is calculated by correcting the PM emission basic amount during normal operation with an increase coefficient corresponding to the common rail pressure subtraction amount, thereby accurately accumulating the PM emission increase amount with a relatively light calculation load. Can be calculated.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
For example, the configuration and arrangement of the engine and auxiliary equipment can be changed as appropriate.
Further, the transient decompression control execution condition, the transient state determination condition, the PM deposition amount estimation method, and the like are not limited to those in the embodiment, and can be changed as appropriate.
For example, in the embodiment, the PM accumulation amount is estimated by calculation based on the operation state of the engine. However, the present invention is not limited to this, and the PM accumulation amount may be estimated based on the differential pressure between the DPF inlet pressure and the outlet pressure. Good. Further, the degree of increase in the exhaust gas temperature may be detected using the change in the heat capacity of the DPF in accordance with the PM accumulation amount, and the PM accumulation amount may be estimated based on this. Furthermore, a combination of these methods can also be used.
Further, in the embodiment, the upper limit number of times of transient pressure reduction control per driving cycle is set, but instead of this, or in addition to this, the upper limit number of times per predetermined travel distance may be set. Good.
Furthermore, the engine to which the present invention is applied is not limited to the diesel engine as in the embodiment, but can be applied to other types of engines.

DESCRIPTION OF SYMBOLS 10 Engine 11 Crankshaft 12 Piston 13 Cylinder block 14 Head 15 Combustion chamber 16 Glow plug 17 Glow controller 20 Turbocharger 21 Compressor 22 Turbine 23 Actuator 24 Negative pressure control valve 30 Intake system 31 Intake duct 32 Air cleaner 33 Air flow meter 34 Intercooler 35 Throttle valve 36 Actuator 37 Intake chamber 38 Intake pressure sensor 39 Intake manifold 40 Exhaust system 41 Exhaust manifold 42 Exhaust pipe 50 Fuel supply device 51 Supply pump 52 Suction metering solenoid valve 53 Fuel temperature sensor 54 Common rail 55 Fuel pressure sensor 56 Injector 60 EGR device 61 EGR passage 6 2 EGR control valve 63 EGR cooler 70 Oxidation catalyst (DOC) 71 Temperature sensor 80 Diesel particulate filter (DPF)
81 Differential pressure sensor 82 Temperature sensor 100 Engine control unit (ECU)
101 accelerator pedal sensor 102 atmospheric pressure sensor

Claims (5)

An engine control device for controlling an engine that injects pressurized fuel in a pressure accumulating chamber into a combustion chamber by an injector,
Requested torque detecting means for detecting driver requested torque;
Particulate matter deposition amount estimation means for calculating an estimated deposition amount of the particulate matter on a filter that captures particulate matter in the exhaust gas;
A pressure reduction control is performed to reduce the fuel pressure in the pressure accumulating chamber over a predetermined period in response to an increase in the required torque, and the pressure reduction control is prohibited when the estimated accumulation amount of the particulate matter exceeds a predetermined value. An engine control device comprising: a fuel pressure control means. 2. The engine control device according to claim 1, wherein the fuel pressure control unit sets an upper limit of a decrease amount of the fuel pressure during the pressure reduction control based on the estimated accumulation amount of the particulate matter. Provided with a filter regeneration means for improving the exhaust gas temperature to regenerate the filter,
The fuel pressure control means executes the pressure reduction control only when the number of executions of the pressure reduction control within a predetermined period or the number of times of execution of the pressure reduction control after completing the most recent regeneration process is less than a predetermined value. The engine control device according to claim 1 or 2. The particulate matter accumulation amount estimation means calculates the estimated accumulation amount using an integrated value of an accumulation amount increase amount associated with execution of the decompression control. The engine control apparatus according to item 1. 5. The accumulation amount increase amount is calculated by correcting the basic discharge amount of the particulate matter during normal operation with an increase coefficient corresponding to the decrease amount of the fuel pressure in the decompression control. Engine control device.

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