JP2015175265A - Urea scr system for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a urea SCR system for an engine capable of temporarily releasing a limitation of operation of the engine when it is required to operate the engine urgently at the time of disaster or the like even if an operation limitation for the engine is set while a residual level of urea water in a urea water tank is less than a prescribed value.SOLUTION: There is provided an operation limitation releasing device 8. The operation limitation of an engine 1 is released by a control device 5 when an operation limitation releasing operation of an operation limitation releasing device 8 is performed after the operation limitation of the engine 1 is set by the control device 5, and then, upon elapsing of a prescribed time, the operation limitation for the engine 1 is started again by the control device 5 and subsequently the operation limitation of the engine 1 is continued by the control device 5 irrespective of a presence or non-presence of supplementing of urea water 4a to a urea water tank 4.

Description

The present invention relates to a urea SCR system for an engine, and more specifically, even when the remaining amount level of urea water in a urea water tank is less than a predetermined value and the operation of the engine is restricted, the engine is operated urgently in the event of a disaster. The present invention relates to an urea SCR system for an engine that can temporarily release the engine operation restriction.

  Conventionally, as an engine urea SCR system, an engine, an exhaust purification device, and a control device are provided. The exhaust purification device includes a urea SCR catalyst, a urea water tank, a urine hydrophobic level sensor, a urea water injector, and a control device. The urea water in the water tank is mixed with the exhaust gas by the urea water injector, the nitrogen oxide in the exhaust gas is reduced by the urea SCR catalyst, and the remaining amount level of the urea water in the urea water tank is less than a predetermined value. There is a configuration in which the operation of the engine is limited by the control device based on the detection by the urea water level sensor (see, for example, Patent Document 1).

  According to this type of urea SCR system, nitrogen oxides in exhaust gas can be efficiently purified with urea water and a urea SCR catalyst, and if the urea water is not replenished, engine operation is restricted. There is an advantage that unauthorized use of an engine that operates the engine without replenishing urea water can be prevented.

  However, this Patent Document 1 has a problem because it does not have means for releasing the engine operation restriction.

JP 2012-2061 A (see FIG. 4)

<< Problem >> Even if it is necessary to urgently operate the engine at the time of a disaster, there is a problem that the engine operation restriction cannot be released.
In the case of the patent document 1, since it is impossible to procure urea water such as a road breakage due to a disaster or the like, even if the engine operation is restricted, there is no means for canceling the operation restriction. For example, even if it is necessary to operate the engine urgently, there is a problem that the engine operation restriction cannot be released. In this case, it is not possible to carry out necessary activities at the time of disaster such as rescue activities and transportation of goods using the engine-equipped machine.

  The problem of the present invention is that even when the remaining amount level of urea water in the urea water tank is less than a predetermined value and the operation of the engine is restricted, the engine must be operated urgently in the event of a disaster. It is an object of the present invention to provide an engine urea SCR system capable of temporarily releasing the operation restriction.

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 1, an engine (1), an exhaust purification device (2), and a control means (5) are provided.
The exhaust purification device (2) includes a urea SCR catalyst (3), a urea water tank (4), a urea water level sensor (6), and a urea water injector (9), and urea water in the urea water tank (4). (4a) is mixed with the exhaust water (10) by the urea water injector (9), and nitrogen oxides in the exhaust (10) are reduced by the urea SCR catalyst (3).
Based on the fact that the remaining amount level of the urea water (4a) in the urea water tank (4) is less than a predetermined value, the control means (5) detects the engine ( In the urea SCR system of the engine, which is configured so that the operation restriction of 1) is performed,
As shown in FIG. 1 and FIG. 2, an operation restriction release device (8) is provided, and after the operation restriction (S2) of the engine (1) is made by the control device (5), the operation restriction release device (6) When the operation restriction release operation is performed, the operation restriction of the engine (1) is released by the control device (5) (S4), and after a predetermined time has elapsed, the control device (5) causes the engine (1) to be turned off. The operation restriction (S6) is resumed, and thereafter the operation restriction (S6) of the engine (1) is continued regardless of whether or not the urea water tank (4) is replenished with the urea water (4a). An urea SCR system for an engine, characterized in that

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> When it is necessary to urgently operate the engine at the time of a disaster, the engine operation restriction can be temporarily released.
As shown in FIG. 1 and FIG. 2, an operation restriction release device (8) is provided, and after the operation restriction (S2) of the engine (1) is made by the control device (5), the operation restriction release device (6) When the operation restriction release operation is performed, the operation restriction of the engine (1) is canceled (S4) by the control device (5). Therefore, when it is necessary to operate the engine urgently at the time of a disaster, The engine operation restriction can be temporarily released. For this reason, it is possible to perform necessary activities in the event of a disaster, such as rescue activities and transportation of goods, using the engine-equipped machine.

<Effect> Unauthorized use of an engine that is not deliberately replenished with urea solution without intention is prevented.
As illustrated in FIG. 1 and FIG. 2, the operation restriction of the engine (1) is canceled (S4) by the control device (5), and after a predetermined time has elapsed, the control device (5) The operation restriction (S6) is resumed, and thereafter the operation restriction (S6) of the engine (1) is controlled by the control device (5) regardless of whether the urea water tank (4) is replenished with the urea water (4a). Since it is configured to be continued, if it is not during a disaster and it is operated without intentionally replenishing the urea water (4a), the operation restriction (S6) of the engine (1) cannot be released, and urea water ( Since a large loss that cannot be compared with the cost required for the replenishment of 4a) is incurred, unauthorized use of an engine that is operated without intentionally replenishing the urea water is suppressed even during a disaster.

The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1.
<Effect> The effect of suppressing unauthorized use of the engine is increased.
Since the engine (1) operation restriction by the control device (5) prohibits restart of the engine (1), unauthorized use of the engine (1) that operates without replenishing the urea water (4a) is extremely large loss The effect of suppressing unauthorized use of the engine (1) is enhanced.

(Invention of Claim 3)
The invention according to claim 3 has the following effect in addition to the effect of the invention according to claim 1 or claim 2.
<Effect> It is difficult for the operation to cancel the restriction to occur.
As illustrated in FIG. 1, the operation restriction canceling operation is performed by restricting the input terminal (7a) of the remaining amount level signal input wire (7) from the remaining amount level signal output terminal (6a) of the urea water level sensor (6). Since it is an operation to reconnect to the release signal output terminal (5a), it is unlikely to cause an erroneous operation of canceling the luck restriction due to engine vibration or contact of the operator during maintenance.

It is a mimetic diagram of a urea SCR system of a diesel engine concerning an embodiment of the present invention. It is a flowchart of the process regarding the engine driving | operation restriction | limiting by the control apparatus used with the system of FIG.

  FIGS. 1 and 2 are diagrams for explaining a urea SCR system for an engine according to an embodiment of the present invention. In this embodiment, a urea SCR system for a diesel engine will be described. SCR is an abbreviation for Selective Catalytic Reduction.

The outline of the urea SCR system is as follows.
As shown in FIG. 1, an engine (1), an exhaust purification device (2), and a control means (5) are provided.
The exhaust purification device (2) includes a urea SCR catalyst (3), a urea water tank (4), a urea water level sensor (6), and a urea water injector (9), and urea water in the urea water tank (4). (4a) is mixed with the exhaust gas (10) by the urea water injector (9), and nitrogen oxides in the exhaust gas (10) are reduced by the urea SCR catalyst (3).
Based on the fact that the remaining amount level of the urea water (4a) in the urea water tank (4) is less than a predetermined value, the control means (5) detects the engine ( It is configured so that the operation restriction of 1) is made.

The configuration of the engine (1) is as follows.
As shown in FIG. 1, in the engine (1), a cylinder head (12) is assembled to an upper part of a cylinder block (11), a cylinder head cover (13) is assembled to an upper part of the cylinder head (12), and a cylinder block ( 11) is assembled with a transmission gear case (14), an engine cooling fan (15) is disposed at the front, a flywheel (16) is disposed at the rear of the cylinder block (11), and a cylinder block ( An oil pan (17) is assembled to the lower part of 11).
An exhaust manifold (18) is assembled on one side of the cylinder head (12), and an intake manifold (not shown) is assembled on the other side of the cylinder head (12). A starting motor (19) is assembled on one side of the cylinder block (11).

The configuration of the exhaust emission control device (2) is as follows.
As shown in FIG. 1, the exhaust purification device (2) includes a DPF case (20), an SCR case (21), and a urea water tank (4).
The DPF case (20) and the SCR case (21) are connected in series downstream of the exhaust manifold (18). The upstream side is the DPF case (20) and the downstream side is the SCR case (21). A DOC (22) and a DPF (23) are accommodated in the DPF case (20). The upstream side is the DOC (22), and the downstream side is the DPF (23). The SCR case (21) contains a urea SCR catalyst (3) and an ammonia purifying oxidation catalyst (24). The upstream side is the urea SCR catalyst (3), and the downstream side is the ammonia purification oxidation catalyst (24). DOC is an abbreviation for diesel oxidation catalyst, and DPF is an abbreviation for diesel particulate filter.
The DPF case (20) and the SCR case (21) are connected by a urea water mixing passage (25), and a urea water injector (9) is disposed in the urea water mixing passage (25).

The supply structure of urea water is as follows.
As shown in FIG. 1, the urea water (4a) in the urea water tank (4) is supplied to the urea water injector (9) through the urine hydrophobic supply line (26). The urine hydrophobic supply line (26) is provided with a urea water supply pump (27). A urea water return line (28) is provided between the urea water injector (9) and the urea water tank (4), and part of the urea water (4a) supplied to the urea water injector (9) is urea. Without being injected by the water injector (9), the urea water injector (9) is cooled and returned to the urea water tank (4) from the urea water return line (28).
The urea water tank (4) includes a urea water level sensor (6), and the urea water level sensor (6) controls the remaining amount level signal of the urea water (4a) in the urea water tank (4) by the control device (5). ) Is output.

The control device (5) is an engine ECU. ECU is an abbreviation for electronic control unit and is a microcomputer.
As shown in FIG. 1, a urea water level sensor (6) and a starting motor (19) are electrically connected to the control device (5).

  As shown in FIGS. 1 and 2, the urea SCR system includes an operation restriction release device (8), and after the operation restriction (S2) of the engine (1) is performed by the control device (5), the operation restriction release device. When the operation restriction release operation of (6) is performed, the operation restriction of the engine (1) is released (S4) by the control device (5), and after a predetermined time has passed, the engine (5) The operation restriction (S6) of (1) is resumed, and thereafter the operation restriction of the engine (1) is performed by the control device (5) regardless of whether the urea water (4a) is replenished to the urea water tank (4). (S6) is configured to be continued.

The details of the operation restriction are as follows.
The operation restriction of the engine (1) by the control device (5) is prohibition of restart of the engine (1). When the urea water (4a) in the urea water tank (4) becomes less than a predetermined amount, the function of the starting motor (19) is stopped by the control device (5) and the restart of the engine is prohibited. .
The operation limitation of the engine (1) may be output limitation of the engine (1) instead of prohibiting restart of the engine (1).

The operation restriction release operation is performed as follows.
As shown in FIG. 1, the urea water tank (4) includes a urea water level sensor (6) and its remaining amount level signal output terminal (6a), and the control device (5) has a remaining amount level signal input wire (7). And its input terminal (7a) and an operation restriction release signal output terminal (5a).
The operation restriction release device (8) is composed of an input terminal (7a) of the remaining amount level signal input electric wire (7) and an operation restriction release signal output terminal (5a).
In the operation restriction release operation, the input terminal (7a) of the remaining amount level signal input wire (7) is changed from the remaining amount level signal output terminal (6a) of the urea water level sensor (6) to the operation restriction release signal output terminal (5a). When the operation restriction is released, an operation restriction release signal is output from the operation restriction release signal output terminal (5a) to the input terminal (7a) of the remaining amount level signal input wire (7). The engine (1) is restricted from being operated by (5).

The flow of processing for restricting the operation of the engine (1) and releasing the restriction of operation by the control means (5) is as follows.
As shown in FIG. 2, in step (S1), it is determined whether the remaining amount level of the urea water (4a) in the urea tank (4) is less than a predetermined value. If the determination is negative, the determination in step (S1) is repeated, and if the determination is affirmative, the process proceeds to step (S2).
In step (S2), engine operation is restricted. Specifically, restart of the engine is prohibited. That is, when the engine is stopped, it cannot be restarted.
When engine operation is restricted in step (S2), the process proceeds to step (S3).
In step (S3), it is determined whether or not a driving restriction release operation has been performed. If the determination is negative, the determination in step (S3) is repeated, and if the determination is affirmative, the process proceeds to step (S4).

In step (S4), the engine operation restriction is released. Specifically, engine restart is permitted.
When the engine operation restriction is removed in step (S4), the process proceeds to step (S5).
In step (S5), it is determined whether or not a predetermined time has elapsed since the engine start restriction was removed. Specifically, it is determined whether or not 24 hours have elapsed.
If the determination is negative, the determination in step (S5) is repeated, and if the determination is affirmative, the process proceeds to step (S6).
In step (S6), the engine operation restriction is resumed, and thereafter, the operation restriction in step (S6) continues regardless of whether or not the urea water tank (4) is replenished with urea water (4a).
The engine operation limitation in step (S2) and step (S6) may be output limitation of engine (1) instead of prohibiting restart of engine (1).

(1) Engine
(2) Exhaust purification device
(3) Urea SCR catalyst
(4) Urea water tank
(4a) Urea solution
(5) Control device
(5a) Operation restriction release signal output terminal
(6) Urea water level sensor
(6a) Remaining level signal output terminal
(7) Remaining level signal input wire
(7a) Input terminal
(8) Restriction release device
(9) Urea water injector
(10) Exhaust
(S2) Engine operation restrictions
(S4) Engine operation restrictions are removed
(S6) Engine operation restrictions

Claims (3)

An engine (1), an exhaust purification device (2), and a control means (5);
The exhaust purification device (2) includes a urea SCR catalyst (3), a urea water tank (4), a urea water level sensor (6), and a urea water injector (9), and urea water in the urea water tank (4). (4a) is mixed with the exhaust water (10) by the urea water injector (9), and nitrogen oxides in the exhaust (10) are reduced by the urea SCR catalyst (3).
Based on the fact that the remaining amount level of the urea water (4a) in the urea water tank (4) is less than a predetermined value, the control means (5) detects the engine ( In the urea SCR system of the engine, which is configured so that the operation restriction of 1) is performed,
When the operation restriction release device (8) is provided and the operation restriction release operation of the operation restriction release device (6) is performed after the operation restriction (S2) of the engine (1) is performed by the control device (5), The control restriction of the engine (1) is canceled by the control device (5) (S4), and after a predetermined time has elapsed, the control restriction of the engine (1) (S6) is resumed by the control device (5). The operation restriction (S6) of the engine (1) is continued by the control device (5) regardless of whether the urea water (4a) is replenished to the urea water tank (4). The urea SCR system for engines. The engine urea SCR system of claim 1,
An urea SCR system for an engine, characterized in that the operation restriction of the engine (1) by the control device (5) is prohibition of restart of the engine (1). In the urea SCR system for an engine according to claim 1 or 2,
The urea water tank (4) includes a urea water level sensor (6) and its remaining amount level signal output terminal (6a), and the control device (5) includes a remaining amount level signal input wire (7) and its input terminal (7a). And an operation restriction release signal output terminal (5a),
The operation restriction release device (8) is composed of an input terminal (7a) of the remaining amount level signal input wire (7) and an operation restriction release signal output terminal (5a).
In the operation restriction release operation, the input terminal (7a) of the remaining amount level signal input wire (7) is changed from the remaining amount level signal output terminal (6a) of the urea water level sensor (6) to the operation restriction release signal output terminal (5a). When the operation restriction is released, an operation restriction release signal is output from the operation restriction release signal output terminal (5a) to the input terminal (7a) of the remaining amount level signal input wire (7). An urea SCR system for an engine, characterized in that the operation restriction of the engine (1) according to (5) is released.

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