WO2018194160A1

WO2018194160A1 - Filter regeneration control device and filter regeneration control method

Info

Publication number: WO2018194160A1
Application number: PCT/JP2018/016319
Authority: WO
Inventors: 遊大景山; 和貴大石
Original assignee: いすゞ自動車株式会社
Priority date: 2017-04-21
Filing date: 2018-04-20
Publication date: 2018-10-25
Also published as: JP2018178979A; CN110546353B; CN110546353A; JP6729473B2

Abstract

A filter regeneration control device and a filter regeneration control method for preventing sulfur poisoning of a filter. An ECU (7) comprises: a concentration determination unit (110) which, when a filter regeneration implementation condition is satisfied, determines whether a sulfur concentration in fuel supplied to a diesel engine (1) or in exhaust gas is greater than or equal to a threshold value; and a regeneration control unit (120) which, if the sulfur concentration is not greater than or equal to the threshold value, controls a fuel injection device (6) to implement conventional filter regeneration. If the sulfur concentration is greater than or equal to the threshold value, the regeneration control unit (120) controls the fuel injection device (6) to implement special filter regeneration in which the value of at least one of fuel injection time and fuel injection amount is increased compared with the conventional filter regeneration.

Description

Filter regeneration control device and filter regeneration control method

The present disclosure relates to a filter regeneration control device and a filter regeneration control method for controlling regeneration of a filter that collects particulate matter in exhaust gas.

Conventionally, a DPF (Diesel Particulate Filter) that collects particulate matter (Particulate Matter: hereinafter referred to as PM) contained in exhaust gas of a diesel engine is known.

Part of the PM collected by the DPF is burned by high-temperature exhaust gas discharged from the diesel engine (referred to as passive regeneration or continuous regeneration), and the rest is deposited on the DPF. When the amount of accumulated PM exceeds a certain amount, for example, a decrease in output of the diesel engine, a decrease in fuel consumption, and damage to the DPF due to abnormal PM combustion occur.

Therefore, it is known to perform filter regeneration (also referred to as forced regeneration) to regenerate the filter by forcibly burning the PM accumulated in the DPF by fuel injection (for example, post injection or exhaust pipe injection). (For example, refer to Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-54631

However, when a fuel having a high sulfur concentration is used, there is a problem that the DPF is poisoned with sulfur and the performance of the DPF is remarkably lowered.

An object of the present disclosure is to provide a filter regeneration control device and a filter regeneration control method that can prevent sulfur poisoning of a filter.

A filter regeneration control device according to an aspect of the present disclosure is provided on a downstream side of a catalyst in a flow path of an exhaust gas of an internal combustion engine of a vehicle, and a filter that collects PM contained in the exhaust gas is forced by fuel injection. A filter regeneration control device that controls the execution of filter regeneration to be regenerated, and determines whether the sulfur concentration of the fuel or the exhaust gas is equal to or greater than a threshold when the filter regeneration execution condition is satisfied When the sulfur concentration is not equal to or higher than the threshold, the fuel injection device is controlled to execute normal filter regeneration when the sulfur concentration is not equal to or higher than the threshold, and when the sulfur concentration is equal to or higher than the threshold, A regeneration control unit for controlling the fuel injection device, wherein the normal filter regeneration is an operation of injecting a first amount of the fuel during a first time period. The filter regeneration is the operation of injecting the first amount of the fuel for a second time longer than the first time, the second being greater than the first amount during the first time. Or the operation of injecting the second amount of the fuel during the second time period.

A filter regeneration control method according to an aspect of the present disclosure includes a filter that is provided on a downstream side of a catalyst in an exhaust gas flow path of an internal combustion engine of a vehicle, and that forcibly collects PM contained in the exhaust gas by fuel injection. A filter regeneration control method for controlling execution of filter regeneration to be reproduced by
Determining whether the sulfur concentration of the fuel or the exhaust gas is equal to or higher than a threshold when the filter regeneration execution condition is satisfied, and executing normal filter regeneration when the sulfur concentration is not higher than the threshold Controlling the fuel injection device to control the fuel injection device to perform special filter regeneration when the sulfur concentration is equal to or greater than a threshold value. An operation of injecting a first amount of the fuel for a period of one time, and the special filter regeneration is to inject the first amount of the fuel for a second time longer than the first time. An operation of injecting, an operation of injecting a second amount of the fuel that is greater than the first amount during the first time, or a second amount of the fuel during the second time Injecting action, either A.

According to the present disclosure, sulfur poisoning of the filter can be prevented.

FIG. 1 is a conceptual diagram illustrating an example of a post-processing device and its peripheral configuration according to an embodiment of the present disclosure. FIG. 2 is a block diagram illustrating a configuration example of the ECU according to the embodiment of the present disclosure. FIG. 3 is a flowchart illustrating an operation example of the ECU according to the embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

First, a post-processing apparatus and its peripheral configuration according to an embodiment of the present disclosure will be described with reference to FIG.

FIG. 1 is a conceptual diagram showing an example of a post-processing apparatus and its peripheral configuration according to the present embodiment. In FIG. 1, a solid arrow indicates a gas flow, and a broken arrow indicates a signal flow.

1 is mounted on a vehicle, for example.

An intake passage (intake passage) 2 is connected to the upstream side of a diesel engine (an example of an internal combustion engine, hereinafter referred to as an engine) 1, and an exhaust passage 3 is connected to the downstream side of the engine 1.

A turbocharger (supercharger) 4 is provided between the air supply passage 2 and the exhaust passage 3. The turbocharger 4 has a compressor 4 a disposed in the air supply passage 2 and an exhaust turbine 4 b disposed in the exhaust passage 3. The compressor 4a is coaxially driven by the exhaust turbine 4b.

An intercooler 5 is provided in the air supply passage 2. The air discharged from the compressor 4 a is cooled by the intercooler 5 and flows into the combustion chambers (not shown) in the cylinders (not shown) of the engine 1.

The engine 1 is provided with a common rail fuel injection device (hereinafter referred to as a fuel injection device) 6 that injects fuel into a combustion chamber in each cylinder. The fuel injection device 6 includes a pump 6a, a common rail 6b, and a fuel injection valve (injector) 6c.

For example, in the fuel injection device 6, the pump 6a pumps a predetermined amount of fuel from the fuel tank 8 at a predetermined timing based on a control signal from the ECU 7 (details will be described later with reference to FIG. 2). To the fuel injection valve 6c. The fuel injection valve 6c injects the supplied fuel into the combustion chamber.

Fuel is stored in the fuel tank 8. The fuel tank 8 is provided with a concentration sensor that detects the concentration of sulfur contained in the stored fuel (hereinafter referred to as sulfur concentration). The concentration sensor 9 appropriately outputs a signal indicating the detected sulfur concentration to the ECU 7.

In the example of FIG. 1, the concentration sensor 9 is provided in the fuel tank 8, but the installation position of the concentration sensor 9 is not limited to the position of FIG. 1 as long as the sulfur concentration of the fuel can be detected.

The exhaust passage 3 is provided with an oxidation catalyst (Diesel Oxidation Catalyst: hereinafter referred to as DOC) 10 and a DPF 11 as post-treatment devices. The DOC 10 is provided on the upstream side of the DPF 11.

The DOC 10 oxidizes and removes hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas and oxidizes nitrogen monoxide (NO) in the exhaust gas to generate nitrogen dioxide (NO ₂ ).

As described above, the DPF 11 collects PM such as soot contained in the exhaust gas and removes it from the exhaust gas.

The exhaust gas discharged from the engine 1 passes through the exhaust passage 3 and drives the exhaust turbine 4b to drive the compressor 4a coaxially. Thereafter, the exhaust gas flows in the order of DOC10 and DPF11.

Heretofore, the post-processing apparatus according to the present embodiment and its peripheral configuration have been described.

Next, the configuration of the ECU 7 (an example of a filter regeneration control device) according to the present embodiment will be described with reference to FIG.

The ECU 7 includes, for example, a CPU (Central Processing Unit), a storage medium such as a ROM (Read Only Memory) storing a control program, a working memory such as a RAM (Random Access Memory), and a communication circuit. The functions of the units shown in FIG. 2 described below are realized by the CPU executing the control program.

ECU7 controls execution of filter regeneration for forcibly regenerating DPF11. Specifically, the ECU 7 controls execution of fuel injection (for example, post injection) of the fuel injection device 6.

As shown in FIG. 2, the ECU 7 includes a concentration determination unit 110 and a regeneration control unit 120.

The concentration determination unit 110 determines whether or not a sulfur concentration detected by the concentration sensor 9 (hereinafter referred to as a detected sulfur concentration) exceeds a predetermined threshold when a predetermined execution condition is satisfied.

The predetermined execution condition is a condition necessary for execution of filter regeneration. For example, the traveling distance of the vehicle exceeds a predetermined distance, or an estimated amount of PM accumulated in the DPF 11 is predetermined. Exceeding the amount.

The threshold value is, for example, a value smaller than a sulfur concentration at which sulfur poisoning can occur (for example, a value obtained through experiments or simulations). However, if the threshold is too small, the frequency of special filter regeneration, which will be described later, increases, resulting in deterioration of fuel consumption. Therefore, it is desirable that the threshold value be set to a value close to the sulfur concentration at which sulfur poisoning occurs.

When the concentration determination unit 110 determines that the detected sulfur concentration is less than the threshold value, the regeneration control unit 120 outputs a normal control signal that instructs the fuel injection device 6 to perform normal filter regeneration.

Normal filter regeneration is an operation of injecting a predetermined amount (hereinafter referred to as a first amount) of fuel for a predetermined time (hereinafter referred to as a first time).

The fuel injection device 6 performs normal filter regeneration when receiving a normal control signal.

On the other hand, when the concentration determination unit 110 determines that the detected sulfur concentration is equal to or greater than the threshold value, the regeneration control unit 120 outputs a special control signal that instructs the fuel injection device 6 to execute the special filter regeneration.

The special filter regeneration is an operation of injecting a first amount of fuel for a time longer than the first time (hereinafter referred to as a second time), and during the first time, than the first amount. An operation for injecting a large amount of fuel (hereinafter referred to as a second amount) (operation for raising the temperature of the exhaust gas higher than that during normal filter regeneration), or a second amount of fuel for the second time period. One of the actions to be performed. Which of these operations is the special filter regeneration may be set, for example, when the ECU 7 is manufactured, or may be set by a vehicle user or the like. Further, the setting may be changed as appropriate.

When the fuel injection device 6 receives the special control signal, it performs special filter regeneration.

The configuration of the ECU 7 according to the present embodiment has been described above.

Next, the operation of the ECU 7 according to the present embodiment (an example of a filter regeneration control method) will be described with reference to FIG. The flow of FIG. 3 is repeatedly performed while the vehicle is traveling.

First, the concentration determination unit 110 determines whether or not the detected sulfur concentration is equal to or higher than a threshold when the predetermined execution condition is satisfied (step S101).

If the detected sulfur concentration is not greater than or equal to the threshold value (step S101: NO), the regeneration control unit 120 controls the fuel injection device 6 to perform normal filter regeneration (step S102).

Specifically, as described above, the regeneration control unit 120 outputs a normal control signal instructing execution of normal filter regeneration to the fuel injection device 6. Then, the fuel injection device 6 performs normal filter regeneration based on the normal control signal received from the regeneration control unit 120.

On the other hand, when the detected sulfur concentration is equal to or higher than the threshold (step S101: YES), the regeneration control unit 120 controls the fuel injection device 6 so as to execute the special filter regeneration (step S103).

Specifically, as described above, the regeneration control unit 120 outputs a special control signal instructing execution of the special filter regeneration to the fuel injection device 6. Then, the fuel injection device 6 performs special filter regeneration based on the special control signal received from the regeneration control unit 120.

The operation of the ECU 7 according to the present embodiment has been described above.

As described in detail, according to the present embodiment, when the sulfur concentration of the fuel is equal to or higher than the threshold value, at least one of the fuel injection time and the fuel injection amount is larger than the normal filter regeneration. Filter regeneration is executed. Thereby, sulfur poisoning of DPF11 can be prevented. Moreover, sulfur poisoning of DOC10 can also be prevented.

Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above-described embodiments, and may be appropriately modified and implemented without departing from the spirit of the present disclosure. Is possible. Hereinafter, each modification will be described.

[Modification 1]
In the above embodiment, the case where the fuel injection during filter regeneration is post injection has been described as an example. However, fuel injection (so-called exhaust pipe injection) is performed by a fuel injection valve (not shown) provided in the exhaust passage 3. May be performed.

[Modification 2]
In the above-described embodiment, the case where the concentration sensor 9 detects the sulfur concentration of the fuel has been described as an example. For example, the ECU 7 may calculate (measure or estimate) the concentration of sulfur contained in the exhaust gas.

[Modification 3]
In the above embodiment, the case where the DOC 10 is provided on the upstream side of the DPF 11 has been described as an example, but the present invention is not limited to this. For example, in FIG. 1, an occlusion type nitrogen oxide reduction catalyst (LNT) may be provided instead of the DOC 10. In that case, sulfur poisoning of LNT can be prevented.

[Modification 4]
Although the case where the internal combustion engine is a diesel engine has been described as an example in the above embodiment, the internal combustion engine may be a gasoline engine. In that case, in FIG. 1, instead of the DPF 11, a GPF (Gasoline Particulate Filter) for collecting particulate matter contained in the exhaust gas of the gasoline engine is provided. Therefore, the sulfur poisoning of GPF can be prevented.

[Modification 5]
In the above-described embodiment, the second time or the second amount may be a fixed value, or may be a variable value that varies according to a detected sulfur concentration that is equal to or greater than a threshold value.

<Summary of this disclosure>
A filter regeneration control device according to the present disclosure is a filter that is provided downstream of a catalyst in an exhaust gas flow path of an internal combustion engine of a vehicle, and forcibly regenerates a filter that collects PM contained in the exhaust gas by fuel injection. A filter regeneration control device that controls execution of regeneration, wherein a concentration determination unit that determines whether a sulfur concentration of the fuel or the exhaust gas is equal to or greater than a threshold when the filter regeneration execution condition is satisfied; If the sulfur concentration is not greater than or equal to the threshold value, the fuel injection device is controlled to perform normal filter regeneration, whereas if the sulfur concentration is greater than or equal to the threshold value, the fuel injector is configured to perform special filter regeneration. And the normal filter regeneration is an operation of injecting a first amount of the fuel during a first time, and the special filter regeneration. An operation of injecting the first amount of the fuel for a second time longer than the first time; a second amount greater than the first amount during the first time; Either the operation of injecting the fuel or the operation of injecting the second amount of the fuel during the second time period.

In the filter regeneration control device, the second time or the second amount may be a value that varies according to the sulfur concentration equal to or greater than the threshold value.

In the filter regeneration control device, the sulfur concentration of the fuel may be a value detected by a concentration sensor that detects the sulfur concentration of the fuel stored in a fuel tank.

In the filter regeneration control device, the catalyst may be an oxidation catalyst or an occlusion type nitrogen oxide reduction catalyst.

Further, in the filter regeneration control device, the internal combustion engine may be a diesel engine, and the filter may be a DPF.

Further, in the filter regeneration control device, the internal combustion engine may be a gasoline engine, and the filter may be a GPF.

A filter regeneration control method according to the present disclosure is a filter that is provided downstream of a catalyst in an exhaust gas flow path of an internal combustion engine of a vehicle, and forcibly regenerates a filter that collects PM contained in the exhaust gas by fuel injection. A filter regeneration control method for controlling execution of regeneration, wherein when the filter regeneration execution condition is satisfied, determining whether a sulfur concentration of the fuel or the exhaust gas is equal to or higher than a threshold value; and When the sulfur concentration is not equal to or higher than the threshold value, the fuel injection device is controlled to perform normal filter regeneration. On the other hand, when the sulfur concentration is equal to or higher than the threshold value, the fuel injection device is controlled to perform special filter regeneration. The normal filter regeneration is an operation of injecting a first amount of the fuel during a first time, and the special filter regeneration is An operation of injecting the first amount of the fuel for a second time longer than the first time, a second amount of the second amount being greater than the first amount during the first time. Either an operation of injecting fuel or an operation of injecting the second amount of the fuel during the second time period.

This application is based on a Japanese patent application (Japanese Patent Application No. 2017-084767) filed on April 21, 2017, the contents of which are incorporated herein by reference.

The filter regeneration control device and the filter regeneration control method of the present disclosure are useful for a filter regeneration control device and a filter regeneration control method that control forced regeneration of a filter that collects PM contained in exhaust gas.

1 Diesel engine (an example of an internal combustion engine)
DESCRIPTION OF SYMBOLS 2 Supply passage 3 Exhaust passage 4 Turbocharger 4a Compressor 4b Exhaust turbine 5 Intercooler 6 Fuel injection device 6a Pump 6b Common rail 6c Fuel injection valve 7 ECU (an example of filter regeneration control device)
8 Fuel tank 9 Concentration sensor 10 DOC (Example of catalyst)
11 DPF (example of filter)
110 Concentration determination unit 120 Reproduction control unit

Claims

Filter regeneration control for controlling the execution of filter regeneration that is provided downstream of the catalyst in the exhaust gas flow path of the internal combustion engine of the vehicle and forcibly regenerates the filter that collects PM contained in the exhaust gas by fuel injection A device,
A concentration determination unit that determines whether a sulfur concentration of the fuel or the exhaust gas is equal to or higher than a threshold when the filter regeneration execution condition is satisfied;
When the sulfur concentration is not equal to or higher than the threshold value, the fuel injection device is controlled to perform normal filter regeneration. On the other hand, when the sulfur concentration is equal to or higher than the threshold value, the fuel injection device is controlled to perform special filter regeneration. A playback control unit that
The normal filter regeneration is
Injecting a first amount of the fuel during a first time;
The special filter regeneration is
An operation of injecting the first amount of the fuel for a second time longer than the first time, a second amount of the second amount being greater than the first amount during the first time. Either an operation of injecting fuel, or an operation of injecting the second amount of the fuel during the second time period.
Filter regeneration control device.
The second time or the second amount is a value that varies according to the sulfur concentration equal to or higher than the threshold value.
The filter regeneration control device according to claim 1.
The sulfur concentration of the fuel is a value detected by a concentration sensor that detects the sulfur concentration of the fuel stored in a fuel tank.
The filter regeneration control device according to claim 1.
The catalyst is an oxidation catalyst or an occlusion type nitrogen oxide reduction catalyst.
The filter regeneration control device according to claim 1.
The internal combustion engine is a diesel engine;
The filter is a DPF;
The filter regeneration control device according to claim 1.
The internal combustion engine is a gasoline engine;
The filter is a GPF;
The filter regeneration control device according to claim 1.
Filter regeneration control for controlling the execution of filter regeneration that is provided downstream of the catalyst in the exhaust gas flow path of the internal combustion engine of the vehicle and forcibly regenerates the filter that collects PM contained in the exhaust gas by fuel injection A method,
Determining whether the sulfur concentration of the fuel or the exhaust gas is equal to or higher than a threshold when the filter regeneration execution condition is satisfied;
When the sulfur concentration is not equal to or higher than the threshold value, the fuel injection device is controlled to perform normal filter regeneration. On the other hand, when the sulfur concentration is equal to or higher than the threshold value, the fuel injection device is controlled to perform special filter regeneration. And a step of
The normal filter regeneration is
Injecting a first amount of the fuel during a first time;
The special filter regeneration is
An operation of injecting the first amount of the fuel for a second time longer than the first time, a second amount of the second amount being greater than the first amount during the first time. Either an operation of injecting fuel, or an operation of injecting the second amount of the fuel during the second time period.
Filter regeneration control method.