JP7156051B2 - Control device - Google Patents

Description

The present invention relates to a control device for controlling the combustion state of an internal combustion engine in a machine fitted with an exhaust pipe fuel injector.

With the tightening of exhaust gas regulations in recent years, in order to purify the exhaust gas of internal combustion engines more than ever, filters are attached to exhaust pipes to collect particulate matter contained in the exhaust gas of internal combustion engines. ing.

When the amount of particulate matter collected by the filter reaches a specified amount, it is necessary to remove the particulate matter collected by the filter by burning the particulate matter collected by the filter. There is

In order to efficiently burn the particulate matter collected by the filter, it is necessary to increase the exhaust temperature efficiently. is injected to efficiently raise the exhaust temperature.

JP 2018-96314 A JP 2012-127301 A JP 2010-24981 A

However, after assembly of an internal combustion engine (after installing a new exhaust pipe fuel injector) or after replacement of an exhaust pipe fuel injector, soot, which inhibits heat transfer from the exhaust to the exhaust pipe fuel injector, is generated in the exhaust pipe fuel. Since there is no deposit on the surface of the injector, the exhaust pipe fuel injector is susceptible to heat damage and damage.

In view of the above circumstances, there is provided a control device capable of suppressing heat damage and damage to an exhaust pipe fuel injector after assembly of an internal combustion engine or replacement of the exhaust pipe fuel injector.

A control device for controlling the combustion state of an internal combustion engine in a machine to which an exhaust pipe fuel injector is attached, wherein the state in which the exhaust pipe fuel injector is removed is changed to the state in which the exhaust pipe fuel injector is attached. Provided is a control device for changing the combustion state of the internal combustion engine from a normal combustion state to a combustion state in which soot is intentionally generated when a soot is generated.

When the driving time of the internal combustion engine after the combustion state of the internal combustion engine is changed from the normal combustion state to the combustion state that intentionally generates soot reaches a predetermined cumulative time, It is desirable to return the combustion state from the combustion state that intentionally generates the soot to the normal combustion state.

It is desirable to detect the change from the state in which the exhaust pipe fuel injector is removed to the state in which the exhaust pipe fuel injector is attached based on an input signal from an external device.

It is possible to provide a control device that can prevent the exhaust pipe fuel injector from being damaged by heat damage after the internal combustion engine is assembled or after the exhaust pipe fuel injector is replaced.

It is a figure explaining the structure of the control apparatus which concerns on embodiment. It is a figure explaining operation|movement of the control apparatus which concerns on embodiment.

Hereinafter, embodiments will be described in order of the accompanying drawings.

As shown in FIG. 1, a control device 100 controls the combustion state of an internal combustion engine 103 in a machine (hereinafter referred to as vehicle) 102 to which an exhaust pipe fuel injector 101 is attached. ( Electronic Control Unit ) and electrical or electronic circuits.

The exhaust pipe fuel injector 101 is attached to the exhaust upstream side of the filter 105 attached to the exhaust pipe 104 . The exhaust pipe fuel injector 101 injects fuel through the exhaust pipe 104 to efficiently raise the temperature of the exhaust gas, thereby promoting the combustion of particulate matter ( PM ) captured by the filter 105. . The internal combustion engine 103 is composed of a diesel engine or a gasoline engine.

When the state in which the exhaust pipe fuel injector 101 is removed is changed to the state in which the exhaust pipe fuel injector 101 is attached, the control device 100 changes the combustion state of the internal combustion engine 103 from the normal combustion state to the soot state. change to a combustion state that generates

If the internal combustion engine 103 is a gasoline engine, the normal combustion state means an ideal combustion state in which the actual air-fuel ratio is controlled to approach the stoichiometric air-fuel ratio in order to maximize the combustion efficiency of the internal combustion engine 103. . If the internal combustion engine 103 is a diesel engine, it means the combustion state when fuel is injected according to the original fuel injection amount map. That is, in principle, the combustion state of the internal combustion engine 103 is controlled so as to be in a normal combustion state.

Combustion conditions that intentionally generate soot refer to non-ideal combustion conditions that are controlled to generate more soot than normal combustion conditions. A combustion state that intentionally generates soot can generally be said to be a combustion state that should be avoided. Originally, the combustion state of the internal combustion engine 103 is controlled to be a combustion state that intentionally generates soot. No problem.

A combustion state that intentionally generates soot is realized by lowering the actual air-fuel ratio below the stoichiometric air-fuel ratio or by retarding the ignition point from the normal ignition point. The actual air-fuel ratio can be adjusted by controlling the opening of the intake throttle valve 106 (intake air amount) and the energization time of the in-cylinder fuel injector 107 (fuel injection amount). The ignition point can be changed by adjusting the energization timing of the in-cylinder fuel injector 107 .

If the vehicle 102 is equipped with an exhaust gas recirculation ( EGR ) device, the combustion state is changed to intentionally generate soot in order to prevent soot from flowing into the exhaust gas recirculation flow path. It is desirable to close the exhaust gas recirculation valve before.

Furthermore, as long as there is no problem with the operation of the internal combustion engine 103, other routes are selected so that the soot does not flow into any other route except the route through which the soot reaches the exhaust pipe fuel injector 101. It is preferable to keep it closed.

The control device 100 controls the internal combustion engine 103 when the drive time of the internal combustion engine 103 after the combustion state of the internal combustion engine 103 is changed from the normal combustion state to the combustion state that intentionally generates soot reaches a predetermined accumulated time. The combustion state of the engine 103 is returned from the combustion state that intentionally generates soot to the normal combustion state.

The predetermined cumulative time is determined based on the time required for a sufficient amount of soot to accumulate on the surface of the exhaust pipe fuel injector 101 to inhibit heat damage. Therefore, when a combustion condition that intentionally generates soot is maintained intermittently or continuously for a predetermined cumulative time, the surface of the exhaust pipe fuel injector 101 is exposed to an amount sufficient to inhibit heat damage. of soot is deposited.

For example, immediately after the combustion state of the internal combustion engine 103 is changed from the normal combustion state to the combustion state that intentionally generates soot, the internal combustion engine 103 is stopped, and the deposition of soot on the surface of the exhaust pipe fuel injector 101 is prevented. Even if it is insufficient, the combustion state of the internal combustion engine 103 is maintained in a combustion state that intentionally generates soot when the internal combustion engine 103 is started next time. is reliably deposited.

A change from a state in which the exhaust pipe fuel injector 101 is removed to a state in which the exhaust pipe fuel injector 101 is attached can be detected based on an input signal from the external device 108 .

For example, after replacement of the exhaust pipe fuel injector 101, the mechanic can manually send a signal to the controller 100 using the external device 108. FIG. Furthermore, the control device 100 may have a function of automatically detecting attachment or detachment of the exhaust pipe fuel injector 101 by itself.

Next, the operation of the control device 100 will be specifically described.

As shown in FIG. 2, in step S101, based on an input signal from the external device 108, it is determined whether the state in which the exhaust pipe fuel injector 101 has been removed has changed to the state in which the exhaust pipe fuel injector 101 has been attached. to detect Specifically, in the presence of an input signal from the external device 108, the controller 100 changes from having the tailpipe fuel injector 101 removed to having the tailpipe fuel injector 101 installed. and transmits a response signal indicating that the input signal from the external device 108 has been received to the external device 108. Upon receiving the response signal from the control device 100, the external device 108 sends the control device 100 stop (reset) the transmission of the input signal of

If a change from the state in which the exhaust pipe fuel injector 101 is removed to the state in which the exhaust pipe fuel injector 101 is attached is detected, the process proceeds to step S102, and if the change is not detected, the process returns.

In step S102, if the flag is off, the flag is turned on, and the combustion state of the internal combustion engine 103 is changed from the normal combustion state to the combustion state in which soot is intentionally generated.

In the next step S103, it is determined whether the driving time of the internal combustion engine 103 after the combustion state of the internal combustion engine 103 is changed from the normal combustion state to the combustion state that intentionally generates soot has reached a predetermined accumulated time. judge.

If it is determined that the driving time of the internal combustion engine 103 after the combustion state of the internal combustion engine 103 is changed from the normal combustion state to the combustion state that intentionally generates soot has reached the predetermined cumulative time, step S104. , and if it is not determined that the driving time of the internal combustion engine 103 has reached the predetermined accumulated time, step S103 is repeated.

In step S104, the flag is turned off, and the combustion state of the internal combustion engine 103 is returned from the combustion state in which soot is intentionally generated to the normal combustion state.

In the first step S105, it is determined whether or not the flag is ON. If the flag is ON, the process proceeds to step S102, and if the flag is OFF, the process proceeds to step S101. Even if the internal combustion engine 103 is stopped before the driving time of the internal combustion engine 103 reaches the predetermined cumulative time, the combustion state that intentionally generates soot is maintained until the driving time of the internal combustion engine 103 reaches the predetermined cumulative time. It can be continued.

As described above, in the control device 100, after the internal combustion engine 103 is assembled or after the exhaust pipe fuel injector 101 is replaced, the combustion state of the internal combustion engine 103 is controlled to be different from the original combustion state, and the exhaust gas is discharged from the exhaust pipe. Since soot, which hinders heat transfer to the fuel injector 101, is deposited on the surface of the exhaust pipe fuel injector 101, damage to the exhaust pipe fuel injector 101 due to heat damage can be suppressed.

Note that the control device 100 can be applied not only to the internal combustion engine 103 of the vehicle 102 but also to an industrial engine of an industrial machine.

100 Control device 101 Exhaust pipe fuel injector 102 Vehicle 103 Internal combustion engine 104 Exhaust pipe 105 Filter 106 Intake throttle valve 107 In-cylinder fuel injector 108 External device

Claims (3)

A control device for controlling the combustion state of an internal combustion engine in a machine equipped with an exhaust pipe fuel injector,
Combustion that intentionally generates soot from a normal combustion state of the internal combustion engine when the state in which the exhaust pipe fuel injector is removed is changed to the state in which the exhaust pipe fuel injector is attached. A control device characterized by changing state. When the driving time of the internal combustion engine after the combustion state of the internal combustion engine is changed from the normal combustion state to the combustion state that intentionally generates soot reaches a predetermined cumulative time, 2. The control device according to claim 1, wherein the combustion condition is returned from the intentionally soot-generating combustion condition to the normal combustion condition. The control device according to claim 1 or 2, wherein a change from a state in which the exhaust pipe fuel injector is removed to a state in which the exhaust pipe fuel injector is attached is detected based on an input signal from an external device.

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