KR20200002605A - Engine working machine - Google Patents

Abstract

The present invention provides an engine working machine capable of suppressing dysfunction of an exhaust catalyst and degradation of engine performance. If a fuel supply amount of a fuel supply device (19a) reaches a prescribed dummy load cancellation determination value by an increase of a total load of an engine (E) including a dummy load and a work load while supplying the dummy load to the engine (E), the supplying of the dummy load is canceled by a switch of a load switch device (7) by an electronic control device (20). If the fuel supply amount of the fuel supply device (19a) reaches a prescribed dummy load resupplying determination value by a decrease of the work load while supplying the work load to the engine without including the dummy load, the dummy load is resupplied by a switch of the load switch device (7) by the electronic control device (20). An exhaust temperature of an inlet of an exhaust catalyst (34) is maintained at a value exceeding a prescribed setting value by maintaining the fuel supply amount at a value exceeding a prescribed setting value while operating the engine.

Description

Engine work machine {ENGINE WORKING MACHINE}

TECHNICAL FIELD This invention relates to an engine work machine. Specifically, It is related with what can suppress the malfunction of an exhaust catalyst and the fall of engine output.

Background Art Conventionally, an engine work machine includes an engine, an exhaust catalyst provided in an exhaust path of an engine, an HC adhesion amount estimating apparatus, and an intake throttle valve, and estimates HC attached to the exhaust catalyst with an HC adhesion amount estimating apparatus during engine operation When the estimated value of the adhesion of HC attached to the exhaust catalyst is larger than the predetermined value, the intake throttle valve may be adjusted to increase the exhaust temperature (see Patent Document 1, for example). HC is short for hydrocarbon.

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2015-31178 (see FIGS. 1 and 2)

In Patent Literature 1, since the exhaust temperature is raised after the estimated adhesion value of HC attached to the exhaust catalyst becomes larger than a predetermined value during engine operation, HC stuck to the inlet or surface of the catalyst remains without incineration and the exhaust catalyst May fall into malfunction.

In addition, if the intake throttle valve is narrowed during engine operation, the amount of intake air is insufficient, resulting in a decrease in output of the engine or incomplete combustion, which may result in a decrease in engine performance.

An object of the present invention is to provide an engine work machine capable of suppressing malfunction of an exhaust catalyst and deterioration of engine performance.

In the present invention, when the fuel supply amount of the fuel supply device reaches a predetermined dummy load release determination value due to the increase in the total load of the engine including the dummy load and the work load during the introduction of the dummy load to the engine, Due to the switching of the load switching device by the control device, the input of the dummy load is canceled, and the fuel supply amount of the fuel supply device is lowered by the lowering of the workload during the input of the workload to the engine not including the dummy load. When the dummy load reloading determination value is reached, the dummy load is reloaded by switching the load switching device by the electronic control device, and the fuel supply amount is maintained by exceeding the predetermined set value during engine operation. The exhaust temperature at the inlet of the exhaust catalyst is configured to maintain a value exceeding a predetermined set value.

This engine work machine is preferably applied to an engine generator.

According to the present invention, the following effects are obtained.

Even when the work load not including the dummy load is low during engine operation, the exhaust temperature at the inlet of the exhaust catalyst is maintained at a value exceeding a predetermined set value by the introduction of the dummy load, and HC is the inlet of the exhaust catalyst. B is lost by catalytic combustion or evaporation before sticking on the surface, and it is possible to suppress malfunction of the exhaust catalyst due to residual HC at the inlet of the exhaust catalyst.

In addition, in raising the exhaust temperature at the inlet of the exhaust catalyst, during the engine operation, adjustment of the intake throttle valve can be made unnecessary or the adjustment amount can be reduced, so that the reduction of the output of the engine and incomplete combustion due to insufficient intake amount are suppressed. In this way, a decrease in engine performance can be suppressed.

1 is a schematic diagram of an engine work machine according to an embodiment of the present invention.
FIG. 2 is a graph showing the relationship between the load of the engine work machine of FIG. 1 and the fuel supply amount. FIG.
3 is a time chart showing a change in fuel supply amount with respect to a change in a work load and a dummy load.
FIG. 4 is a flowchart of a process of inputting and releasing a dummy load by the electronic control apparatus of the engine work machine of FIG. 1.
FIG. 5 is a flowchart of a DPF regeneration process by the electronic control apparatus of the engine work machine of FIG. 1.

1 to 5 are diagrams illustrating an engine work machine according to an embodiment of the present invention. In this embodiment, an engine generator of a standing water-cooled series four-cylinder diesel engine provided with an exhaust treatment apparatus will be described. .

The outline of this engine work machine is as follows.

As shown in FIG. 1, the engine E includes a cylinder block 11, a cylinder head 12 assembled on an upper portion of the cylinder block 11, and a fly provided at a rear portion of the cylinder block 11. Wheel 13, engine cooling fan 14 provided in the front of cylinder block 11, intake manifold (not shown) arrange | positioned at the transverse one side of cylinder head 12, and a cylinder head An exhaust manifold 16 disposed on the other side of the lateral side 12, a supercharger 17 connected to the exhaust manifold 16, and an exhaust downstream of the supercharger 17. An exhaust treatment case 18, a fuel supply device 19a, and an electronic control device 20 are provided.

The workload device 6 is connected to the flywheel 13.

Although the generator 6a, a hydraulic apparatus, or a welding machine can be used for the workload device 6, the generator 6a is used in this embodiment.

The outline of the intake apparatus is as follows.

As shown in FIG. 1, the intake apparatus includes a compressor 17a of the supercharger 17, an air cleaner 21 disposed on the intake upstream side of the compressor 17a, an air cleaner 21, and a compressor 17a. An air flow sensor 22 disposed between the intercooler 23 disposed on the intake downstream side of the compressor 17a, an intake throttle valve 24 disposed on the intake downstream side of the intercooler 23, and an intake throttle An intake manifold (not shown) is provided on the intake downstream side of the valve 24.

The air flow sensor 22 and the electric actuator 24a of the intake throttle valve 24 are electrically connected to the electronic control apparatus 20.

The engine ECU is used for the electronic control apparatus 20. ECU is short for electronic control unit and is a microcomputer.

The outline of the fuel supply device 19a is as follows.

As shown in FIG. 1, the fuel supply apparatus 19a is a common rail type | formula and distributes the some fuel injector 25 and the accumulated fuel which were inserted into each cylinder to the some fuel injector 25. As shown in FIG. The common rail 26, the fuel supply pump 27 which conveys fuel to the common rail 26, and the fuel tank 28 are provided.

The fuel supply pump 27 and the solenoid valve 25a of the fuel injector 25 are electrically connected to the electronic control apparatus 20. The target rotational speed sensor 29, the crankshaft sensor 30, and the cylinder discrimination sensor 31 are electrically connected to the electronic control apparatus 20. The target rotational speed of the engine is detected by the target rotational speed sensor 29, and the actual rotational speed and the crank angle of the engine are detected by the crankshaft sensor 30. In the cylinder discrimination sensor 31, the combustion stroke of each cylinder is detected.

When an accelerator is used instead of the target rotation speed setting lever such as a tractor or combine, an Excel sensor is used instead of the target rotation speed sensor, and the target rotation speed is set based on the detection of the Excel position by the Excel sensor. do.

It goes without saying that the engine speed may be variably adjusted by signals such as an Excel sensor or CAN communication from the vehicle ECU.

In the fuel supply device 19a, the engine load is calculated by the electronic control apparatus 20 based on the deviation between the target rotational speed of the engine and the actual rotational speed, and the fuel injector ( The solenoid valve 25a of 25 is valve-opened for a predetermined time, and a predetermined amount of fuel 32 is injected from the fuel injector 25 into each cylinder at a predetermined timing. The fuel 32 is diesel.

As shown in FIG. 1, the target rotation speed sensor 29 detects the target rotation speed setting position of the target rotation speed setting lever 29a, and the potentiometer is used for the target rotation speed sensor 29. As shown in FIG. The target rotation speed is set to a predetermined rotation speed such as 1800 rpm or 3600 rpm by the target rotation speed setting lever 29a.

As shown in FIG. 1, the crankshaft sensor 30 detects the passage of the processus | protrusion of the crankshaft detection disk 30a provided in the flywheel 13. As shown in FIG. The crankshaft detection disk 30a has one starting point protrusion and a plurality of phase protrusions provided at equal pitches on the periphery of the crankshaft detection disk 30a. The actual engine speed is calculated, and the crank angle is calculated based on the phase difference from the starting projection of the passed phase projection.

The cylinder discrimination sensor 31 detects the passage of the projection of the cylinder discriminating disc 31a provided on the valve actuating camshaft (not shown). The cylinder discriminating disk 31a is provided with one projection at the periphery, and the combustion stroke of four cycles is discriminated by the electronic control apparatus 20 based on the passage of this projection.

An electronic pickup sensor is used for the crankshaft sensor 30 and the cylinder discrimination sensor 31.

The outline of the exhaust device is as follows.

As shown in FIG. 1, the exhaust apparatus exhausts the exhaust manifold 16, the exhaust turbine 17b of the supercharger 17 provided in the exhaust downstream of the exhaust manifold 16, and the exhaust turbine 17b. The exhaust gas processing apparatus 33 provided in the downstream side is provided. A series of paths from the exhaust manifold 16 to the exhaust treatment device 33 becomes the exhaust path 1.

The outline of the exhaust gas treatment device 33 is as follows.

The exhaust treatment apparatus 33 includes an exhaust treatment case 18 provided on the exhaust downstream side of the exhaust turbine 17b of the supercharger 17, and a DOC 35 disposed on the exhaust upstream side in the exhaust treatment case 18. And the DPF 2 disposed on the exhaust downstream side in the exhaust case 18.

DPF is an abbreviation of diesel particulate filter and captures PM in engine exhaust. PM is an abbreviation of particulate matter. As shown in FIG. 1, the DPF 2 includes a wall flow-type ceramic honeycomb in which a plurality of cells (not shown) along the axial length direction are arranged inside, and alternately sealed inlets and outlets of neighboring cells are alternately sealed. Is used.

DOC is short for diesel oxidation catalyst and oxidizes CO (carbon monoxide) and NO (nitrogen monoxide) in the engine exhaust. In the DOC 35, a flow-through ceramic honeycomb in which a plurality of cells (not shown) along the axial length direction are provided in a penetrating phase is used inside the DOC 35. In the cell, platinum, palladium, rhodium, or the like is used. The oxidation catalyst component is supported.

The exhaust gas treatment apparatus 33 includes a regeneration device R of the DPF 2.

The regeneration device R of the DPF 2 includes a PM deposition amount estimating device 4 for estimating the deposition amount of PM deposited on the DPF 2, an exhaust temperature raising device 19, and an electronic control device 20. And the electronic control apparatus 20 is configured to perform the regeneration process of the DPF 2 based on the PM accumulation amount of the DPF 2 reaching a predetermined regeneration start value, and the regeneration process of the DPF 2. In the exhaust heating apparatus 19, the exhaust 39 is heated up so that the PM accumulated in the DPF 2 is incinerated.

The PM accumulation amount estimating apparatus 4 is comprised by the electronic control apparatus 20, and based on the differential pressure detected by the differential pressure sensor 3 which detects the differential pressure on the exhaust inlet side and the exhaust outlet side of the DPF 2, The amount of PM deposited on the DPF 2 is estimated. Instead of the differential pressure of the DPF 2, the accumulated amount of PM accumulated in the DPF 2 may be estimated based on the integrated value of the engine operation time and the integrated value of the fuel supply amount.

The exhaust temperature raising device 19 has an exhaust temperature at the DOC inlet side which detects the exhaust temperature at the exhaust inlet side of the intake throttle valve 24, the fuel supply device 19a, the DOC 35, and the DOC 35. On the DPF inlet side for detecting the sensor 37, the exhaust temperature sensor 36 on the DPF outlet side for detecting the exhaust temperature on the exhaust outlet side of the DPF 2, and the exhaust temperature on the exhaust inlet side for the DPF 2 An exhaust temperature sensor 38 is provided.

Each of the sensors 36, 37, 38 is electrically connected to the electronic control device 20.

As shown in FIG. 1, the exhaust treatment apparatus 33 captures PM in the exhaust 39 of the engine in the DPF 2, and oxidizes NO (nitrogen monoxide) in the exhaust 39 in the DOC 35. Based on the NO ₂ (nitrogen dioxide) obtained, the PM deposited on the DPF 2 is continuously oxidized and burned at a relatively low temperature, and the differential pressure detected by the differential pressure sensor 3 reaches a predetermined regeneration required value. Under the control of the control device 20, unburned fuel supplied to the exhaust 39 is catalytically burnt in the DOC 35 by post injection of the common rail type fuel supply device 19a. 39) is heated up, and the PM deposited on the DPF 2 is burned at a relatively high temperature to regenerate the DPF 2.

When the exhaust temperature is low and the inlet exhaust temperature of the DOC 35 does not reach the activation temperature of the DOC 35, the intake throttle valve 24 is adjusted by the control of the electronic controller 20. This raises the exhaust temperature.

The start time of the regeneration process of the DPF is as follows.

When the differential pressure detected by the differential pressure sensor 3 reaches the regeneration required value, when the inlet exhaust temperature of the DOC 35 reaches the activation temperature of the DOC 35, and post injection is started at that point, The start time of the post injection is the start time of the regeneration process of the DPF.

When the differential pressure detected by the differential pressure sensor 3 reaches the regeneration required value, the inlet side exhaust temperature of the DOC 35 does not reach the activation temperature of the DOC 35 and the intake throttle valve 24 is adjusted. In this case, the throttle start time of the intake throttle valve 24 becomes the start time of the regeneration process of the DPF. In this case, the inlet exhaust temperature of the DOC 35 reaches the activation temperature of the DOC 35, and the time point at which post injection is started may be defined as the start time point of the regeneration process of the DPF.

In addition, instead of post injection of the common rail type fuel supply device 19a, the exhaust 39 is discharged from an exhaust pipe fuel injector (not shown) disposed between the exhaust turbine 17b of the supercharger 17 and the DOC 35. Exhaust pipe injection for injecting unburned fuel may be used. Instead of the post injection of the common rail type fuel supply device 19a, the exhaust temperature may be increased by the heat generation of the electric heater or the exhaust throttle of the exhaust throttle valve.

As shown in FIG. 1, the engine work machine includes an engine E, an exhaust catalyst 34 disposed in the exhaust path 1 of the engine E, and a fuel supply amount to the combustion chamber as the engine load increases or decreases. A fuel supply device 19a that is increased or decreased, a dummy load device 5, a workload device 6, a load switching device 7 for switching the input and release of the dummy load to the engine E, The electronic control apparatus 20 which controls switching of the load switching apparatus 7 is provided.

As shown in FIG. 2, this engine work machine is supplied with the fuel supply amount of the fuel supply apparatus 19a by the increase of the total load of the engine containing a dummy load and a work load during the injection of the dummy load into the engine E. As shown in FIG. When the predetermined dummy load release determination value is reached, the input of the dummy load is canceled by switching of the load switching device 7 by the electronic control apparatus 20, and the workload to the engine not containing the dummy load. Switching of the load switching device 7 by the electronic control device 20 when the fuel supply amount of the fuel supply device 19a reaches a predetermined dummy load re-insertion determination value due to the lowering of the work load during the injection of. Thus, the dummy load is reloaded and the fuel supply amount is maintained at a value exceeding a predetermined set value during engine operation, whereby the exhaust temperature at the inlet of the exhaust catalyst 34 reaches a value exceeding the predetermined set value. To keep It is.

For this reason, as shown in FIG. 2, even if the workload which does not contain a dummy load during engine operation becomes low, the exhaust temperature of the inlet of the exhaust catalyst 34 exceeds predetermined | prescribed set value by input of a dummy load. The HC is lost by catalytic combustion or evaporation before it is fixed at the inlet or surface of the exhaust catalyst 34, and the exhaust catalyst 34 due to residual HC at the inlet of the exhaust catalyst 34 is maintained. Can impair dysfunction.

In addition, in raising the exhaust temperature of the inlet of the exhaust catalyst 34, during the engine operation, adjustment of the intake throttle valve 24 can be made unnecessary, or the throttle amount can be reduced, resulting in insufficient engine capacity. The fall of output and incomplete combustion are suppressed, and the fall of engine performance can be suppressed.

HC is an abbreviation of hydrocarbon and means PM and SOF powder. PM is an abbreviation of particulate matter, and SOF component is an abbreviation of soluble organic component, and consists of unburned fuel and lubricating oil.

The exhaust catalyst 34 is a DOC 35, but other exhaust catalysts such as an SCR catalyst may be used. SCR catalyst is an abbreviation of Selective Catalytic Reduction type catalyst, and the flow-through honeycomb type in which many cells along the axial length direction are provided in the penetrating phase is used inside.

As shown in FIG. 1, in this engine generator, the workload device 6 is the generator 6a, and the output part 6b of the generator 6a includes an output circuit 6c to the electric device 8, and The dummy load device 5 provided with the dummy electric resistor 5a, and the load switching device 7 for switching the output to the output circuit 6c and the dummy electric resistor 5a. 7 denotes a total load input position 7a for outputting the output of the generator 6a to both the dummy electrical resistor 5a and the electric device 8, and the output of the generator 6a to the dummy electrical resistor 5a. It is provided with the workload input position 7b which outputs to the electric device 8, without outputting to the circuit.

The electric device 8 includes lighting equipment, air conditioning equipment, and the like.

For this reason, even in the case of an engine generator in which there is no output to the electric device 8 or many low driving states continue for a long time during engine operation, the exhaust catalyst 34 is output by the output to the dummy electric resistor 5a. The exhaust temperature at the inlet of the inlet is maintained at a value exceeding a predetermined set temperature, and HC is lost by catalytic combustion or evaporation before it is fixed at the inlet or surface of the exhaust catalyst 34, and the inlet of the exhaust catalyst 34 The malfunction of the exhaust catalyst 34 due to the residual HC in can be suppressed.

Control of the load input by the electronic control apparatus 20 is demonstrated with the graph of FIG. 2, and the time chart of FIG.

Immediately after the engine E is started, if the water temperature of the engine coolant (which may be the oil temperature of the engine oil) reaches a predetermined value, as shown in FIG. 2 or FIG. 3, by initial injection of the dummy load, The fuel supply amount of the fuel supply device 19a is set to an initial input value, and the fuel supply amount of the fuel supply device 19a is predetermined by an increase in the workload during the total load input of the engine including the dummy load and the workload. When the dummy load release determination value is reached, the input of the dummy load is canceled by switching the load switching device 7 by the electronic control apparatus 20, and the fuel supply amount is lowered to a predetermined lowered value.

Next, when the fuel supply amount of the fuel supply apparatus 19a reaches the predetermined | prescribed dummy load reinsertion determination value by the fall of the workload during input of the workload to the engine which does not contain a dummy load, the electronic control apparatus By switching the load switching device 7 by 20, the dummy load is reloaded, and the fuel supply amount rises to a predetermined rising value.

During engine operation, the fuel supply amount is maintained at a value exceeding a predetermined lower limit set value, whereby the exhaust temperature at the inlet of the exhaust catalyst 34 is maintained at a value exceeding the predetermined set value.

The dummy load release determination value is set higher than the rising value of the fuel supply amount at the time of reloading the dummy load, and the dummy load reloading determination value is set lower than the fall value of the fuel supply amount at the time of release of the dummy load, Hysteresis prevents the release of the dummy load and the hunting of the input.

The initial input value and the re-insertion determination value of the dummy load are set to values exceeding a lower limit set value, and the fuel supply amount is maintained at a value exceeding a predetermined lower limit set value during engine operation.

The lower limit set value of the fuel supply amount is a value at which the DOC inlet exhaust temperature exceeds the DOC activation temperature (for example, 200 to 250 ° C.) so that HC adhered to the DOC inlet or surface is lost by catalytic combustion or evaporation. Is set.

The flow chart of FIG. 4 demonstrates the process sequence of inputting and releasing a dummy load by the electronic control apparatus 20. FIG.

As shown in Fig. 4, when the engine is started in step S1, in step S2, when the water temperature of the engine cooling water (which may be the oil temperature of the engine oil) reaches a predetermined dummy load injection determination value, the step ( In step S3, the dummy load is input, and in step S4, it is determined whether or not the total load has reached the dummy load release determination value. The determination of step S4 is repeated until affirmation. If the determination is affirmation, the dummy load is released in step S5, and whether the workload has reached the dummy load reloading determination value in step S6. It is determined whether or not. The determination of step S6 is repeated until affirmation, and if the determination is affirmation, the dummy load is re-injected in step S3.

The procedure of the regeneration process of the DPF by the electronic control apparatus 20 is demonstrated by the flowchart of FIG.

As shown in FIG. 5, it is determined in step S11 whether or not the estimated value of accumulation of PM deposited on the DPF 2 has reached the required reproduction value. The determination at step S11 is repeated until affirmation, and if the determination is affirmation, at step S12 it is determined whether or not the DOC 35 has reached the activation temperature, and if the determination is affirmation, step S13 If the regeneration of the DPF 2 is started at step S, and it is determined at step S14 whether the regeneration termination condition of the DPF 2 is satisfied, and if the determination is affirmative, the process is terminated and the determination is negative. Is returned to step S12.

The regeneration termination condition is that the integration time at which the DPF inlet exhaust temperature maintains the predetermined regeneration request temperature (for example, around 500 ° C.) by post injection reaches a predetermined end setting time.

In addition, during the regeneration of the DPF 2, when the exhaust temperature at the DPF outlet side reaches an abnormal high temperature (for example, around 700 ° C.), the post injection is stopped to avoid thermal damage of the DPF 2. .

In step S12, when the inlet exhaust temperature of the DOC 35 does not reach the activation temperature of the DOC 35, in step S15, the intake adjustment by the intake throttle valve 24 is performed to exhaust the exhaust ( 39) is heated up and returns to step S12.

Due to the introduction of the dummy load, during the engine operation, the inlet exhaust temperature of the DOC 35 exceeds the activation temperature of the DOC 35, but the dummy load such as cold weather or start-up at which the outside temperature is extremely low In spite of the injection, when the inlet exhaust temperature of the DOC 35 does not reach the activation temperature of the DOC 35, the intake throttle by the intake throttle valve 24 is performed in step S15. However, since the inlet-side exhaust temperature of the DOC 35 is set higher than when there is no dummy load by the introduction of the dummy load, the throttle amount of the intake throttle valve 24 is reduced.

(E) ... engine (1) ... exhaust path
(5) ... dummy load device (5a) ... dummy load resistor
(6) ... work load unit (6a) ... generator
(6b) ... output section (6c) ... output circuit
(7) ... load switching device (7a) ... total load input position
(7b) ... working load position (8) ... electrical device
(19a) ... fuel supply (20) ... electronic control unit
(34) ... exhaust catalyst.

Claims (2)

The engine E, the exhaust catalyst 34 disposed in the exhaust path 1 of the engine E, the fuel supply device 19a in which the fuel supply amount to the combustion chamber is increased or decreased controlled in accordance with the increase or decrease of the engine load, and the dummy The electronic device controlling the switching of the load device 5, the workload device 6, the load switching device 7 for switching the input and release of the dummy load to the engine E, and the load switching device 7. With a control device 20,
If the fuel supply amount of the fuel supply device 19a reaches a predetermined dummy load release determination value due to the increase in the total load of the engine including the dummy load and the work load during the introduction of the dummy load into the engine E. When the load switching device 7 is switched by the electronic control device 20, the input of the dummy load is canceled, and the fuel is lowered during the operation of the workload to the engine not containing the dummy load. When the fuel supply amount of the supply device 19a reaches a predetermined dummy load reloading determination value, the dummy load is reloaded by switching the load switching device 7 by the electronic control device 20 and the engine is running. And the fuel supply amount is maintained at a value exceeding a predetermined set value, so that the exhaust temperature at the inlet of the exhaust catalyst (34) is maintained at a value exceeding the predetermined set value. The method according to claim 1,
The workload device 6 is the generator 6a, and the output part 6b of the generator 6a is the dummy load provided with the output circuit 6c to the electric device 8 and the dummy electric resistor 5a. Apparatus 5 and the said load switching device 7 which switch the output to the output circuit 6c and the dummy electric resistor 5a are provided, and this load switching device 7 supplies the output of the generator 6a. The electric device 8 without outputting the total load input position 7a output to both the dummy electric resistor 5a and the electric device 8, and the output of the generator 6a to the dummy electric resistor 5a. An engine work machine, characterized in that it is provided with a workload input position (7b) to output.

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