JP2021113541A - Control device, and control method - Google Patents

Abstract

To make a smoke discharge amount appropriate by acquiring a smoke amount discharged from an engine, and controlling after-injection on the basis of the smoke amount.SOLUTION: A control device of an engine having a fuel injection device is provided which can perform multistage injection including at least main injection and after-injection during one combustion stroke, the control device comprises; a fuel injection control unit controlling fuel injection including at least the after-injection on the basis of an operation state of the engine; a smoke discharge amount acquisition unit acquiring a smoke discharge amount of the engine on the basis of a state amount of an exhaust gas of the engine; and an after-injection correction unit setting an injection amount of the after-injection, or a correction amount of injection timing on the basis of difference between the smoke discharge amount and a reference value when the acquired smoke discharge amount exceeds the prescribed reference value, and correcting the after-injection performed by the fuel injection control unit on the basis of the set correction amount.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a control device and a control method, and more particularly to control of an engine having a fuel injection device capable of multi-stage injection including at least main injection and after injection in one combustion cycle.

Conventionally, as a fuel injection device for an engine, a multi-stage injection type fuel injection device is known. In a multi-stage fuel injection system, the main injection is performed to generate engine torque. Further, the after injection is performed after the main injection in order to burn the smoke generated by the main injection.

For example, Patent Document 1 discloses a technique for reducing the amount of smoke emission by appropriately adjusting the amount of after-injection based on the amount of oxygen in the cylinder.

Japanese Unexamined Patent Publication No. 2012-144022

By the way, when the engine is in a transient operation state or when the intake / exhaust system parts of the engine (for example, the exhaust gas recirculation valve) are deteriorated, the smoke emission amount is targeted in advance even if the after injection is performed after the main injection. It may exceed the standard amount set as the value.

In the technique described in Document 1 above, since the in-cylinder oxygen amount is estimated using the detection signals of the in-cylinder pressure sensor and the rotation speed sensor and the calculation formula including these detection signals, the response delay and calculation of these sensors Due to the increase in load, it may not be possible to guarantee the estimation accuracy of the amount of oxygen in the cylinder. Also, since the after injection amount is corrected based on the amount of oxygen in the cylinder, not the amount of smoke emitted directly from the engine, it may not be possible to suppress the amount of smoke released to the atmosphere below the standard amount. ..

This disclosure has been made in view of the above circumstances, and it is intended to optimize the smoke emission amount by acquiring the smoke amount emitted from the engine and controlling the after injection based on the smoke amount. The purpose.

The apparatus of the present disclosure is an engine control device having a fuel injection device capable of multi-stage injection including at least main injection and after injection in one combustion stroke, and at least the after injection is based on the operating state of the engine. A fuel injection control unit that controls fuel injection including the above, a smoke emission amount acquisition unit that acquires the smoke emission amount of the engine based on the state amount of the exhaust gas of the engine, and the smoke emission amount to be acquired are predetermined. When the value exceeds the reference value of, the correction amount is set based on the difference between the smoke emission amount and the reference value, and the after injection by the fuel injection control unit is corrected based on the set correction amount. It is characterized by including an after-injection correction unit.

Further, when the difference between the smoke emission amount and the reference value is equal to or greater than a predetermined upper limit value, the after injection correction unit corrects the after injection by advancing the injection timing of the after injection by a predetermined amount. It is preferable to do so.

Further, when the engine is in a transient operation state, the after injection correction unit preferably corrects the after injection by retarding the injection timing of the after injection by a predetermined amount.

Further, when the rotation speed of the engine is in a predetermined low rotation speed region, the after injection correction unit may correct the after injection by dividing the after injection in one combustion stroke into at least two or more. preferable.

Further, when the correction amount increases the injection amount of the after injection, the torque calculation unit estimates and calculates the output torque of the engine, which decreases by reducing the injection amount of the main injection by the increase of the injection amount. When the estimated output torque is lower than the required torque for the engine, the main injection amount increase correction unit that corrects the injection amount of the main injection to be larger than the value set by the torque calculation unit. It is preferable to further provide.

The method of the present disclosure is a control method of an engine having a fuel injection device capable of multi-stage injection including at least main injection and after injection in one combustion stroke, and at least the after injection based on the operating state of the engine. The fuel injection including the above is controlled, the smoke emission amount of the engine is acquired based on the state amount of the exhaust gas of the engine, and when the acquired smoke emission amount exceeds a predetermined reference value, the said It is characterized in that the correction amount is set based on the difference between the smoke emission amount and the reference value, and the after injection is corrected based on the set correction amount.

According to the technique of the present disclosure, it is possible to optimize the smoke emission amount by acquiring the smoke amount emitted from the engine and controlling the after injection based on the smoke amount.

It is a schematic overall block diagram which shows the fuel injection device of the engine which concerns on this Embodiment, and the exhaust system. It is a schematic functional block diagram which shows the control device which concerns on this embodiment, and the related peripheral configuration. It is a chart diagram explaining the flow of the process of the fuel injection correction control which concerns on this embodiment.

Hereinafter, the control device according to the present embodiment will be described with reference to the accompanying drawings. The same parts have the same reference numerals, and their names and functions are also the same. Therefore, detailed explanations about them will not be repeated.

[overall structure]
FIG. 1 is a schematic overall configuration diagram showing a fuel injection device and an exhaust system of the engine 10 according to the present embodiment.

As shown in FIG. 1, the fuel injection device of the engine 10 includes a fuel tank 11, a suction pipe 12, a fuel filter 13, a feed pump 14, a supply pump 15, a first supply pipe 16, and a common rail 17. A pressure control valve 18, a second supply pipe 19, an in-cylinder injector 20, and a return pipe 21 are provided.

The fuel tank 11 stores fuel (for example, light oil). One end of the suction pipe 12 is immersed in the fuel in the fuel tank 11, and the other end is connected to the suction port of the feed pump 14. The fuel filter 13 is interposed in the fuel suction pipe 12 and removes foreign substances in the fuel pumped by the feed pump 14.

Both the feed pump 14 and the supply pump 15 are connected to the crankshaft of the engine 10 via a power transmission mechanism (for example, a gear or a belt pulley) (not shown), and are driven by the power of the engine 10. The feed pump 14 supplies the fuel pumped from the fuel tank 11 through the suction pipe 12 to the supply pump 15.

The supply pump 15 includes a plunger that is reciprocated by the rotation of a shaft (not shown), and pressurizes and discharges fuel by the reciprocating motion of the plunger. The high-pressure fuel pressurized by the supply pump 15 is supplied to the common rail 17 from the first supply pipe 16. The drive and discharge amount of the supply pump 15 are feedback-controlled by the control device 100 so that the sensor value of the common rail pressure sensor 90, which will be described later, becomes a predetermined target pressure.

The common rail 17 accumulates the high-pressure fuel supplied from the supply pump 15 and distributes the high-pressure fuel to each in-cylinder injector 20 via the second supply pipe 19. Further, the common rail 17 is provided with a common rail pressure sensor 90 capable of acquiring a common rail pressure corresponding to a fuel injection pressure. The sensor value of the common rail pressure sensor 90 is transmitted to the electrically connected control device 100.

The pressure control valve 18 reduces the pressure of the common rail, and is interposed between the common rail 17 and the return pipe 21. That is, when the pressure control valve 18 is opened, the high-pressure fuel accumulated in the common rail 17 is returned to the fuel tank 11 via the return pipe 21.

The in-cylinder injector 20 is provided in a cylinder head (not shown) above the cylinder block CB, and injects high-pressure fuel supplied from the common rail 17 directly into the cylinder C. A piston (not shown) is housed in the cylinder C so as to be reciprocating. A cavity (not shown) is recessed in the top surface of the piston, and a combustion chamber is partitioned by the top surface of the piston, the inner wall of the cylinder C, and the lower surface of the cylinder head.

The in-cylinder injector 20 is, for example, an injector capable of multi-stage injection such as pilot injection, pre-injection, main injection, after-injection, and post-injection during one combustion cycle of the engine 10. It is installed along the axis of the cylinder C while facing the inside of the combustion chamber). As for the fuel injection amount and injection timing of the in-cylinder injector 20, a predetermined instruction signal (pulse current) according to the operating state of the engine 10 is applied from the control device 100 to the electromagnetic solenoid, and the injection hole at the tip of the nozzle is lifted by the core valve. Is controlled by opening and closing.

The cylinder head of the engine 10 is provided with an exhaust manifold 30 that collects the exhaust gas discharged from each cylinder C. Further, an exhaust pipe 31 for guiding the exhaust gas to the atmosphere is connected to the exhaust manifold 30. The exhaust pipe 31 is provided with a turbine 33 of the supercharger 32, an exhaust aftertreatment device 40, and the like in this order from the exhaust upstream side. Reference numeral 35 indicates an intake pipe, and reference numeral 34 indicates a compressor of the supercharger 32.

The exhaust gas aftertreatment device 40 includes an oxidation catalyst 42 and a filter 43 in this order from the exhaust upstream side.

The oxidation catalyst 42 is formed by supporting a catalyst component or the like on the surface of a ceramic carrier such as a cordierite honeycomb structure, and oxidizes HC and CO contained in the exhaust gas. When unburned fuel (HC) is supplied by the post-injection by the in-cylinder injector 20 or the exhaust pipe injection of the exhaust pipe injector (not shown), the oxidation catalyst 42 oxidizes the unburned fuel (HC) to raise the exhaust temperature.

The filter 43 is formed, for example, by arranging a large number of cells partitioned by a porous partition wall along the flow direction of exhaust gas, and alternately sealing the upstream side and the downstream side of these cells. .. The filter 43 collects particulate matter (PM) in the exhaust gas in the pores and surface of the partition wall, and when the amount of PM deposited reaches a predetermined amount, the filter regeneration is carried out to burn and remove the particulate matter (PM). Will be done. Note that the filter regeneration may be performed at predetermined intervals, such as when the cumulative mileage from the previous filter regeneration execution reaches a predetermined threshold distance.

The engine speed sensor 91 acquires the engine speed Ne from the crankshaft of the engine 10. The accelerator opening sensor 92 acquires the accelerator opening Ac (injection instruction value / required torque to the in-cylinder injector 20) according to the amount of depression of the accelerator pedal (not shown). The PM sensor 93 is provided on the upstream side of the filter 43 of the exhaust pipe 31 and acquires the PM value of the exhaust gas. The differential pressure sensor 94 acquires the front-rear differential pressure ΔP of the filter 43. The sensor values of each of these sensors 91 to 94 are transmitted to the electrically connected control device 100.

FIG. 2 is a schematic functional block diagram showing the control device 100 according to the present embodiment and related peripheral configurations.

The control device 100 is, for example, a device that performs calculations such as a computer, and is a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input port, and an output port connected to each other by a bus or the like. And so on, and execute the program.

Further, the control device 100 executes a program to execute the fuel injection control unit 110, the smoke emission amount estimation unit 120, the after injection correction unit 130, the torque reduction estimation calculation unit 140, the torque determination unit 150, and the main injection amount increase / decrease correction. It functions as a device including the unit 160. Each of these functional elements will be described as being included in the control device 100, which is integrated hardware in the present embodiment, but any part of these may be provided in separate hardware.

The fuel injection control unit 110 controls fuel injection by the in-cylinder injector 20 so as to perform multi-stage injection including main injection and after injection during one combustion cycle based on the operating state of the engine 10. Specifically, in the memory of the control device 100, an instruction injection amount map M1 showing the relationship between the operation state of the engine 10 and the instruction injection amount created in advance by experiments or the like, and the operation state of the engine 10 and the smoke emission amount A smoke emission standard value map M2 showing the relationship with the reference value of is stored. The operating state of the engine 10 includes, for example, an engine speed Ne and an accelerator opening degree Ac.

The fuel injection control unit 110 refers to the indicated injection amount map M1 and the smoke emission standard value map M2 based on the operating state of the engine 10, and refers to the number of times of each multi-stage injection (for example, one pre-injection, one main injection, After injection once, etc.), the injection amount of each multi-stage injection, and the injection timing of each multi-stage injection are set. At this time, regarding the after injection, the injection amount and the injection timing are set so that the smoke emission amount is less than the reference value. In the following description, the injection amount and injection timing of the after-injection set by the fuel injection control unit 110 are referred to as a reference after-injection amount and a reference after-injection timing, respectively. The fuel injection control unit 110 outputs the set energization pulse of each multi-stage injection to the electromagnetic solenoid of the in-cylinder injector 20. When an energization pulse is output to the electromagnetic solenoid of the in-cylinder injector 20, the core valve of the in-cylinder injector 20 is lifted by the time width of the energization pulse, and fuel is injected.

The smoke emission amount estimation unit 120 (an example of the smoke emission amount acquisition unit of the present disclosure) estimates the smoke emission amount in the exhaust gas based on the PM value transmitted from the PM sensor 93. The smoke emission amount may be estimated from the front-rear differential pressure ΔP of the filter 43 transmitted from the differential pressure sensor 94, the model formula referred to based on the operating state of the engine 10, and the like. The smoke emission amount estimated by the smoke emission amount estimation unit 120 is transmitted to the after injection correction unit 130.

The after injection correction unit 130 compares the smoke emission amount set by the fuel injection control unit 110 with the smoke emission amount transmitted from the smoke emission amount estimation unit 120, and the smoke emission amount exceeds the reference value. If so, the after-injection correction for correcting the reference after-injection amount and the reference after-injection timing is performed. Hereinafter, the details of the after injection correction performed by the after injection correction unit 130 will be described.

First, the after injection correction unit 130 calculates the injection amount correction value Q of the after injection so that the smoke emission amount is equal to or less than the emission reference value. Specifically, in the memory of the control device 100, the operating state of the engine 10, the difference ΔS between the smoke emission amount and the reference value, and the injection amount correction for setting the smoke emission amount to the reference value or less, which are obtained in advance by experiments or the like. An injection amount correction map M3 showing the relationship with the value Q is stored. The after injection correction unit 130 calculates the injection amount correction value Q of the after injection by referring to the injection amount correction map M3 based on the operating state of the engine 10 and the difference ΔS between the smoke emission amount and the reference value. .. The injection amount correction value Q is not limited to the map, and may be obtained from a model formula or the like.

Next, the after injection correction unit 130 corrects the timing correction value (advance angle A / retard angle) of the reference after injection timing that gives the best fuel efficiency of the engine 10 when the after injection is corrected by the set injection amount correction value Q. The amount R) and the number of divisions D of the after injection in one combustion cycle are obtained.

More specifically, in the after injection correction unit 130, the engine 10 is not in the transient operation state, the rotation speed of the engine 10 is not in the predetermined low rotation speed region, and the difference between the smoke emission amount and the smoke emission reference value ΔS When is equal to or greater than a predetermined upper limit value, correction (advance correction) is performed to advance the timing of the after injection by a predetermined advance amount A from the reference after injection timing. As a result, it is possible to disturb the combustion gas before smoke is generated due to the combustion of the main injection, reduce the smoke, shorten the combustion time, and improve the fuel efficiency. The specific advance amount A may be set from a map or the like referenced based on the difference ΔS.

Further, when the increase rate of the accelerator opening degree Ac (required torque) acquired by the accelerator opening degree sensor 92 exceeds a predetermined threshold value, the after-injection correction unit 130 uses the after-injection timing as a reference after-injection timing. A correction (retardation correction) is performed to delay the angle by a predetermined amount of retardation R. As a result, it becomes possible to effectively suppress the generation of smoke due to deterioration of the combustion state due to turbo lag or the like during transient operation of the engine. The specific retard angle amount R may be set from a map or the like referred to based on the rate of increase in the accelerator opening degree Ac.

Further, the after-injection correction unit 130 divides the after-injection in one combustion cycle into a plurality of parts in a low rotation speed region where the engine speed Ne acquired by the engine speed sensor 91 is less than a predetermined threshold value, for example. Perform split correction. As a result, in a state where the combustion time is prolonged in the low engine speed region, oxygen in the combustion chamber can be effectively utilized to burn the fuel for after-injection, and the amount of smoke emitted can be effectively reduced. The number of divisions N of the after injection can be any number of divisions such as two or three times, and the number of divisions may be increased as the engine speed Ne becomes lower.

The torque reduction estimation calculation unit 140 (an example of the torque calculation unit of the present disclosure) is used when the injection amount correction value Q set by the after injection correction unit 130 is a positive value (increase correction for increasing the reference after injection amount). When the main injection amount is reduced by an amount corresponding to the injection amount correction value Q in accordance with the increase correction, the estimated output torque value of the engine 10 that decreases is calculated. The output torque estimated value may be calculated from a map (not shown) referred to based on the operating state of the engine 10, or may be obtained from a model formula.

The torque determination unit 150 determines whether or not the output torque estimated value calculated by the torque reduction estimation calculation unit 140 has reached the required torque (target torque) of the engine 10 set based on the accelerator opening degree Ac. .. The determination result of the torque determination unit 150 is transmitted to the main injection amount increase / decrease correction unit 160.

The main injection amount increase / decrease correction unit 160 (an example of the main injection amount increase / decrease correction unit of the present disclosure) receives a determination result that the output torque estimated value does not reach the required torque from the torque determination unit 150. The correction is performed to increase the main injection amount from the value set by the torque reduction estimation calculation unit 140 so that the actual output torque of the engine 10 reaches the required torque. The amount of increase in the main injection may be set from a map (not shown) or the like referred to based on the deviation between the estimated output torque value and the required torque. Further, the main injection amount increase / decrease correction unit 160 sets the main injection amount to the injection amount correction value Q when the torque determination unit 150 transmits a determination result that the output torque estimated value has reached the required torque. Make a correction to reduce the amount by a corresponding amount. By these corrections performed by the main injection amount increase / decrease correction unit 160, deterioration of fuel efficiency can be minimized while maintaining the required torque. The main injection amount corrected by the main injection amount increase / decrease correction unit 160 is transmitted to the fuel injection control unit 110.

Next, the flow of the fuel injection correction control process according to the present embodiment will be described with reference to the flow chart of FIG. This control is started, for example, when the fuel injection control unit 110 determines that the after injection is to be executed.

In step S110, the amount of smoke emitted from the exhaust gas is estimated based on the PM value transmitted from the PM sensor 93.

Next, in step S120, it is determined whether or not the smoke emission amount transmitted from the smoke emission amount estimation unit 120 exceeds the smoke emission standard value transmitted from the fuel injection control unit 110. If yes, the control proceeds to step S130, and if no, the control proceeds to step S300.

In step S130, the injection amount correction value Q of the after injection is calculated so that the smoke emission amount is less than the smoke emission reference value.

In step S300, multi-stage injection including main injection and after injection is performed by normal control without correction.

In step S150, it is determined whether or not the injection amount correction value Q is an increase correction that increases the injection amount of the after injection. If yes, the control proceeds to step S170, and if no, the control proceeds to step S160.

In step S160, the main injection is performed with the reference amount set by the fuel injection control unit 110. After that, this control proceeds to step S210.

In step S170, the estimated output torque when the injection amount of the main injection is reduced by an amount corresponding to the injection amount correction value Q is calculated.

In step S180, it is determined whether or not the estimated output torque has reached the required torque of the engine 10. If yes, the control proceeds to step S200. If negative (No), this control proceeds to step S190.

In step S190, the injection amount of the main injection is increased from the value set by the torque reduction estimation calculation unit 140 so that the output torque reaches the required torque, and the main injection is performed. After that, this control proceeds to step S210.

In step S200, the main injection amount is reduced by the amount corresponding to the injection amount correction value Q, and the main injection is performed. After that, this control proceeds to step S210.

In step S210, it is determined whether the engine 10 is in the transient operation state or the rotation speed of the engine 10 is in the low rotation speed region. If yes, the control proceeds to step S250, and if no, the control proceeds to S220.

In step S220, it is determined whether or not the difference ΔS between the smoke emission amount and the smoke emission standard value is equal to or greater than a predetermined upper limit value. If yes, the control proceeds to step S240, and if no, the control proceeds to S230.

In step S230, the after injection is performed at the injection amount corrected by the injection amount correction value Q and the reference after injection timing. After that, this control is returned.

In step S240, the after injection is performed at the injection amount in which the reference after injection amount is corrected by the injection amount correction value Q and the injection timing in which the reference after injection timing is advanced. After that, this control is returned.

As described above, if the result is affirmative (Yes) in step S210, this control proceeds to S250.

In step S250, it is determined whether or not the engine 10 is in the transient operation state. If yes, the control proceeds to step S260, and if no, the control proceeds to S270 when the engine speed is in the low speed region. When the engine 10 is in the transient operation state, the rotation speed of the engine 10 also increases as the accelerator opening degree Ac increases, so that the rotation speed of the engine 10 is not in the low rotation region.

In step S260, the after injection is performed at the injection amount in which the reference after injection amount is corrected by the injection amount correction value Q and the injection timing in which the reference after injection timing is retard-corrected. After that, this control is returned.

In step S270, the after injection is performed with the injection amount obtained by correcting the reference after injection amount with the injection amount correction value Q and the number of injections corrected by division. After that, this control is returned.

According to the present embodiment described in detail above, the after injection is corrected based on the amount of smoke emitted in the exhaust gas estimated based on the PM value transmitted from the PM sensor 93. As a result, the after injection can be appropriately controlled based on the amount of smoke directly discharged from the engine 10, and the amount of smoke discharged can be effectively suppressed to the reference value or less. Further, by appropriately adjusting the injection timing and the number of divisions of the after injection according to various conditions such as the difference between the smoke emission amount and the reference value, the transient operation state of the engine 10, the low rotation region of the engine 10, and the like. It is also possible to effectively maintain the fuel efficiency of the engine 10 while keeping the smoke emission below the reference value.

The present disclosure is not limited to the above-described embodiment, and can be appropriately modified and implemented without departing from the spirit of the present disclosure.

For example, in the above-described embodiment, the PM sensor 93 has been described as being provided on the upstream side of the filter 43 of the exhaust pipe 31, but the PM sensor 93 is provided on the downstream side of the filter 43 of the exhaust pipe 31 and the filter 43 is provided. The PM value that passes through and flows out to the downstream side may be acquired. In this case, the after injection can be adjusted based on the PM value finally released into the atmosphere.

Further, the conditions for performing the advance angle injection, the retard angle injection, and the split injection in the above-described embodiment are examples, and may be performed based on conditions other than these.

Further, in the above-described embodiment, the correction of the after injection is performed when the smoke emission amount exceeds the smoke emission standard value, but it is performed when the smoke emission amount is less than the predetermined smoke emission amount. You may be disappointed. In this case, under a predetermined condition, the after injection amount can be reduced and the fuel efficiency can be improved in a state where the smoke emission amount is low.

10 Engine 15 Supply pump 17 Common rail 20 In-cylinder injector 43 Filter 100 Control device 110 Fuel injection control unit 120 Smoke emission estimation unit (smoke emission acquisition unit)
130 After injection correction unit 140 Torque reduction estimation calculation unit (torque calculation unit)
150 Torque judgment unit 160 Main injection amount increase / decrease correction unit (main injection amount increase / decrease correction unit)

Claims (6)

An engine control device having a fuel injection device capable of multi-stage injection including at least main injection and after injection during one combustion stroke.
A fuel injection control unit that controls fuel injection including at least the after injection based on the operating state of the engine.
A smoke emission amount acquisition unit that acquires the smoke emission amount of the engine based on the state amount of the exhaust gas of the engine, and
When the acquired smoke emission amount exceeds a predetermined reference value, the correction amount is set based on the difference between the smoke emission amount and the reference value, and the fuel is set based on the set correction amount. A control device including an after-injection correction unit that corrects the after-injection by the injection control unit. When the difference between the smoke emission amount and the reference value is equal to or greater than a predetermined upper limit value, the after injection correction unit corrects the after injection by advancing the injection timing of the after injection by a predetermined amount. Item 1. The control device according to item 1. The control according to claim 1 or 2, wherein the after injection correction unit corrects the after injection by retarding the injection timing of the after injection by a predetermined amount when the engine is in a transient operation state. Device. From claim 1, the after-injection correction unit corrects the after-injection by dividing the after-injection in one combustion stroke into at least two or more when the engine speed is in a predetermined low rotation speed region. The control device according to any one of claims 3. When the correction amount increases the injection amount of the after injection, a torque calculation unit that estimates and calculates the output torque of the engine that decreases by reducing the injection amount of the main injection by the increase of the injection amount.
When the estimated output torque is lower than the required torque for the engine, the main injection amount increase correction unit that corrects the injection amount of the main injection to be larger than the value set by the torque calculation unit is further added. The control device according to any one of claims 1 to 4. It is a control method of an engine having a fuel injection device capable of multi-stage injection including at least main injection and after injection during one combustion stroke.
Controlling fuel injection, including at least the after injection, based on the operating condition of the engine,
Based on the state amount of the exhaust gas of the engine, the smoke emission amount of the engine is acquired.
When the acquired smoke emission amount exceeds a predetermined reference value, the correction amount is set based on the difference between the smoke emission amount and the reference value, and the after A control method characterized by correcting the injection.

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