JP2008014157A - Control device for diesel engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means capable of preventing incomplete regeneration of a DPF due to unstable control of the exhaust gas temperature etc. during DPF regeneration, in a diesel engine making fuel injection irregular when fuel is reduced and performing DPF regeneration. <P>SOLUTION: In the diesel engine 1, normally, when the particulate collection amount of the filter 28 exceeds a first predetermined amount, the filter 28 is regenerated by performing postinjection of fuel from the fuel injection valve 9. Along with the operation of the engine 1, when fuel residual amount becomes below a first set value, a warning lamp 50 is lit. When the fuel residual amount becomes below a second set value, fuel injection is made irregular, and when it becomes below a third set value, fuel injection for producing power of the engine 1 is stopped. When the fuel residual amount becomes below the second set value and the fuel injection is irregularly performed, regeneration of the filter 28 is stopped or prohibited. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, the exhaust passage is provided with a filter for collecting particulates (particulates) in the exhaust gas. On the other hand, the fuel is appropriately supplied to the exhaust gas, and the temperature is increased by the oxidation reaction of the fuel promoted by the oxidation catalyst. The present invention relates to a control device for a diesel engine in which particulates collected by a filter are burned and removed by exhaust gas.

  Generally, an exhaust system of a diesel engine is provided with a filter (diesel particulate filter) that collects particulates (particulates) such as carbon, soot, and hydrocarbons contained in exhaust gas. When the amount of collected particulate matter in the filter reaches a predetermined level, the particulate matter is combusted, for example, by raising the temperature of the exhaust gas to regenerate the filter.

Specifically, for example, when the differential pressure before and after the filter becomes a set value or more, fuel is injected into the combustion chamber from the fuel injection valve at the later stage of the exhaust stroke, and an appropriate amount of fuel is supplied into the exhaust gas, The fuel is burned by an oxidation catalyst disposed upstream of the filter as viewed in the flow direction of the exhaust gas to raise the temperature of the exhaust gas, and the particulates collected by the filter are burned with the high-temperature exhaust gas to burn the filter. A diesel engine that has been regenerated has been proposed (see, for example, Patent Document 1).
JP-A-8-42326 (paragraph [0015], FIG. 1)

  By the way, in general, in a diesel engine, when the fuel runs out and air (air) enters the fuel supply path, the engine cannot be started even if fuel is supplied to the fuel tank unless the air is vented. . In addition, if the air supply mechanism such as a priming pump is provided in the fuel supply system, it is possible to automatically release the air. However, if this is done, the structure of the engine becomes complicated and the manufacturing cost increases. There arises a problem that the degree of freedom in layout of the fuel supply system and the like is reduced.

  For this reason, in a diesel engine (similar to a gasoline engine), a warning light is lit to urge the driver to refuel when the remaining amount of fuel in the fuel tank falls below a predetermined installation value. . However, in the diesel engine, since the air venting is complicated, the warning light is turned on early with a margin, so the driver does not refuel quickly even when the warning light is turned on. There are many cases.

  Therefore, when the remaining amount of fuel in the fuel tank is further reduced, the normal operation state of the engine (for example, the engine vibration state) is determined by irregularizing the fuel injection of the fuel injection valve. It can be considered that the driver can always feel that the remaining amount of fuel has decreased and prompt the driver to refuel. However, if this is done, the filter may be regenerated when the fuel injection is irregular. In this case, temperature control of the exhaust gas is disturbed, for example, the exhaust gas becomes abnormally hot and the filter is damaged, or conversely, the exhaust gas temperature does not rise sufficiently and the combustion of particulates is insufficient. Therefore, there is a problem that normal filter regeneration may not be performed.

  The present invention has been made in order to solve the above-described conventional problems. When the remaining amount of fuel in the fuel tank is reduced, the fuel injection of the fuel injection valve is made irregular, etc. Means that make it possible to prevent incomplete regeneration of the filter due to disturbance of exhaust gas temperature control, etc., for a diesel engine whose operating state differs from the normal state Providing is a problem to be solved.

  In order to solve the above problems, a diesel engine or a control device thereof according to the present invention includes (a) a filter that collects particulates (particulates) in exhaust gas discharged from the engine, and (b) exhaust gas. An oxidation catalyst for heating the filter by accelerating the oxidation reaction of the fuel therein to raise the temperature of the exhaust gas, and (c) a parameter detection means for detecting a parameter related to the amount of collected particulate matter of the filter, (d ) When it is determined based on the above parameters that the amount of collected particulates of the filter is greater than or equal to a predetermined amount, the filter is regenerated by injecting fuel for filter regeneration into the fuel injection means and supplying the fuel to the oxidation catalyst. And reproducing means for performing.

  The control device for the diesel engine further includes (e) a remaining amount detecting means for detecting the remaining amount of fuel in the fuel tank, and (f) when the detected remaining amount of fuel falls below a set value. Combustion control means for making the fuel injection amount of the fuel injection means irregular. Here, the regeneration control means interrupts or prohibits the regeneration of the filter when the fuel injection amount is irregularized by the combustion control means.

  When the control device for the diesel engine according to the present invention is provided with warning means for turning on a warning lamp when the remaining amount of fuel in the fuel tank has dropped below the first set value, the combustion control means, When the remaining amount of fuel falls below a second set value that is smaller than the first set value, the fuel injection amount of the fuel injection means is made irregular, and the regeneration means When lit, it is preferable to start the regeneration of the filter even if the amount of collected particulates of the filter is equal to or less than the predetermined amount (that is, regardless of the amount of collected particulates). In this case, the combustion control means is for generating engine power (by the fuel injection means or other fuel injection means) when the remaining amount of fuel becomes equal to or less than a third set value that is smaller than the second set value. More preferably, the fuel injection (all fuel injections) is stopped.

  According to the control device for a diesel engine according to the present invention, the fuel injection amount of the fuel injection means is made irregular when the remaining amount of fuel in the fuel tank falls below a set value. The filter regeneration is interrupted or prohibited when is irregular. For this reason, the exhaust gas temperature control is not disturbed, or the exhaust gas temperature is unstable, etc., resulting in incomplete or abnormal filter regeneration. For example, the exhaust gas becomes abnormally hot and the filter is damaged. It is possible to effectively prevent the occurrence of the exhaust gas temperature and the exhaust gas temperature from being sufficiently increased and insufficient combustion of the fine particles.

  In the control device for a diesel engine according to the present invention, when the remaining amount of fuel is equal to or lower than the first set value and the warning light is turned on, regeneration of the filter is started regardless of the amount of collected particulates, If the fuel injection amount is made irregular when the remaining amount falls below the second set value, the filter is regenerated before the fuel injection amount is made irregular. When the remaining amount of fuel is small, it is possible to prevent or suppress the particulate collection amount of the filter from exceeding the predetermined amount. That is, the regeneration of the filter during engine operation is possible as much as possible.

  Here, if the fuel injection of the fuel injection means is to be stopped (estimated) when the remaining amount of fuel becomes equal to or less than the third set value, before the fuel in the fuel tank runs out. Since the engine is stopped at this time, it is possible to reliably prevent the air from entering the fuel supply system and starting the engine (unless air is released). When the engine or the vehicle stops in this way, the vehicle can be easily continued by receiving, for example, the fuel required to travel to the nearest gas station from the vehicle that has passed.

  Hereinafter, embodiments of the present invention (best mode for carrying out the present invention) will be described in detail with reference to the accompanying drawings.

(Embodiment 1)
As shown in FIG. 1, an engine system E according to Embodiment 1 of the present invention includes a direct injection diesel engine 1 (hereinafter referred to as “engine 1” for short). The engine 1 includes a cylinder head 2 and a cylinder block 3 that form an outer shell thereof. Although FIG. 1 shows only one cylinder (cylinder), the engine 1 is a multi-cylinder engine (for example, an in-line four-cylinder engine) having a plurality of cylinders. In each cylinder of the engine 1, fuel combustion air (intake) is taken into the combustion chamber 6 from the intake port 5 in the intake stroke in which the intake valve 4 is opened.

  The air in the combustion chamber 6 is compressed by a piston 8 fitted in a cylinder 7 (cylinder) to be in a high temperature / high pressure state. Then, near the top dead center of the compression stroke, fuel (for example, light oil) is injected from the fuel injection valve 9 into the high-temperature and high-pressure air in the combustion chamber 6 (main injection), and this fuel self-ignites and burns. . The combustion gas, that is, the exhaust gas generated by the combustion of the fuel is discharged to the exhaust port 11 in the exhaust stroke in which the exhaust valve 10 is opened. These strokes are repeated and the piston 8 reciprocates in the cylinder 7. The reciprocating motion of the piston 8 is converted into the rotational motion of the crankshaft 13 by the connecting rod 12 and the like.

  In order to supply fuel combustion air (intake air) to the combustion chamber 6 of the engine 1, an intake passage 14 having an upstream end opened to the atmosphere as viewed in the air flow direction and a downstream end communicating with the intake port 5 is provided. It has been. The intake passage 14 has an air cleaner 15 that removes dust and the like in the air in order from the upstream side in the air flow direction, an air flow sensor 16 that detects an air flow rate (intake air amount), and an engine 1. A turbocharger 17 (exhaust turbocharger) that performs supercharging, an intercooler 18 that cools air whose temperature has increased due to supercharging, an intake throttle valve 19 that controls the flow rate of air, and the temperature of the air An intake air temperature sensor 20 that detects (intake air temperature), an intake pressure sensor 21 that detects air pressure (intake air pressure), and a surge tank 22 that stabilizes the air flow are provided. On the downstream side of the surge tank 22, the intake passage 14 is divided into independent intake passages 14 a for each cylinder that are independent from each other, and the downstream end of the independent intake passage 14 a is connected to the intake port 5. The turbocharger 17 is a variable turbo whose charging efficiency is variable.

  In order to discharge the combustion gas of the engine 1, that is, the exhaust gas, an exhaust passage 23 is provided whose upstream end communicates with the exhaust port 11 in the exhaust gas flow direction and whose downstream end is open to the atmosphere. In the exhaust passage 23, in order from the upstream side in the flow direction of the exhaust gas, the turbine 17b of the turbocharger 17, a first exhaust temperature sensor 24 for detecting the temperature of the exhaust gas, and a catalytic converter 25 for purifying the exhaust gas. A second exhaust temperature sensor 26 that detects the temperature of the exhaust gas, a first exhaust pressure sensor 27 that detects the pressure of the exhaust gas, and particulates such as carbon, soot, and hydrocarbons contained in the exhaust gas (hereinafter referred to as “patties”). A diesel particulate filter 28 (hereinafter referred to as “filter 28” for short), a second exhaust pressure sensor 29 for detecting the pressure of the exhaust gas, and a temperature of the exhaust gas. A third exhaust temperature sensor 30 is provided.

The catalytic converter 25 includes an oxidation catalyst 25a carrying platinum or platinum plus palladium. The oxidation catalyst 25a promotes an oxidation reaction that at least oxidizes CO and HC in the exhaust gas to generate CO ₂ and H ₂ O. In the first embodiment, the catalytic converter 25 and the filter 28 are provided separately. However, the catalytic converter 25 may be omitted by providing the filter 28 with an oxidation catalyst function instead of this. Further, a catalytic converter 25 and a filter 28 having an oxidation catalyst function may be provided.

  The first exhaust temperature sensor 24 is for detecting the temperature of the exhaust gas immediately before flowing into the catalytic converter 25, and the second exhaust temperature sensor 26 and the third exhaust temperature sensor 30 are immediately before flowing into the filter 28. And the temperature of the exhaust gas immediately after flowing out of the filter 28, respectively.

  The first exhaust pressure sensor 27 and the second exhaust pressure sensor 29 indicate the pressure of the exhaust gas immediately before flowing into the filter 28 and immediately after flowing out of the filter 28 (parameter value related to the amount of particulates collected in the filter 28). Each one is to be detected. The control unit C calculates a differential pressure ΔP before and after the filter 28 from the detection values of the exhaust pressure sensors 27 and 29 in the exhaust gas flow direction, and based on this differential pressure ΔP, the particulates in the filter 28 are calculated. The amount collected (hereinafter referred to as “particulate amount”) is calculated. Note that the larger the differential pressure ΔP, the larger the particulate amount.

  In addition, an EGR passage 31 is provided in which a part of the exhaust gas in the exhaust passage 23 on the upstream side of the turbine 17b is used as EGR gas and is returned to the intake passage 14 between the intake pressure sensor 21 and the surge tank 22. The EGR passage 31 is provided with a water-cooled EGR cooler 32 that cools the EGR gas and an EGR control valve 33 that controls the flow rate of the EGR gas in order from the upstream side in the flow direction of the EGR gas. Thereby, a part of the exhaust gas in the exhaust passage 23 can be recirculated to the intake passage 14 while the flow rate is controlled by the EGR control valve 33.

  Fuel is supplied to the fuel injection valve 9 from the fuel tank 36 through the fuel passage 37. The fuel passage 37 includes a fuel filter assembly 38 that removes foreign matters and dust in the fuel, a high-pressure fuel pump 39 (FIP) driven by the crankshaft 13, and a common rail 40 (fuel distributor) that stores high-pressure fuel. And are installed. The high pressure fuel pump 39 operates so that the fuel pressure in the common rail 40 detected by the common rail pressure sensor 41 is maintained at a predetermined value or more. The fuel tank 36 is provided with a fuel remaining amount sensor 42 for detecting the remaining amount of fuel in the fuel tank 36 (hereinafter referred to as “fuel remaining amount” for short). Note that a vehicle equipped with the engine 1 is provided with a warning lamp 50 that warns the user of fuel refueling when the remaining fuel amount is equal to or lower than a predetermined first set value.

  Although not shown in detail, the fuel filter assembly 38 is provided with a separator (fuel / water separator) for separating and storing water in the fuel by sedimentation, and for discharging water stored in the sedimentor. A drain plug and a fuel heater for heating the fuel to prevent the fuel from solidifying or increasing in viscosity at low temperatures (especially in the case of a cold district specification car) are provided. However, in order to avoid complication of the structure of the engine 1 and to improve the layout of the fuel system and the like, no priming pump that automatically discharges air and moisture is not provided.

  Further, the engine 1 includes a crank angle sensor 43 (engine speed sensor) that detects a crank angle (and thus an engine speed), a water temperature sensor 44 that detects a temperature of cooling water of the engine 1, and an accelerator opening degree. An accelerator opening sensor 45 (see FIG. 2) is provided.

  Further, the engine 1 is provided with a control unit C provided with a computer in order to perform various controls of the engine 1. The control unit C is a comprehensive control means for the engine 1 including a regeneration control means for regenerating the filter 28, a combustion control means for making the fuel injection amount irregular, and a warning means for controlling the warning light 50. It is. Although not shown in detail, the control unit C includes an input / output unit for inputting / outputting control signals, a storage unit (ROM, RAM, etc.) for storing data, a central processing unit (CPU), a timer counter, etc. It has.

  As shown in FIG. 2, the control unit C includes a fuel injection valve 9, a turbocharger based on various data detected by the sensors 16, 20, 21, 24, 26, 27, 29, 30, 42 to 45. By controlling the charger 17, the intake throttle valve 19, the EGR control valve 33, the warning lamp 50, etc., fuel injection control (including filter regeneration control), EGR control, supercharging control, fuel shortage avoidance control (engine stall control, Rule control). Note that the EGR control and the supercharging control are well known to those skilled in the art, and such control is not the gist of the present invention, and thus the description thereof is omitted.

  Hereinafter, an outline of the control method of the fuel injection control and the fuel shortage avoidance control by the control unit C will be described. First, an outline of a control method for fuel injection control (including filter regeneration control) will be described. The fuel injection control for controlling the fuel injection valve 9 includes main injection control for injecting fuel into the combustion chamber 6 near the top dead center of the compression stroke to generate power for the engine 1, and post-injection for regeneration of the filter 28. Control (sub-injection control), that is, filter regeneration control.

  In the main injection control, the fuel injection amount and the fuel injection timing are controlled. This main injection control is basically performed based on the engine speed and the engine load, and is further corrected based on the engine water temperature, the intake air temperature, and the like. The engine load is calculated based on the accelerator opening (depressed amount of the accelerator pedal) detected by the accelerator opening sensor 45. On the other hand, the post-injection control, that is, the filter regeneration control is detected by the first and second exhaust pressure sensors 27 and 29, the crank angle sensor 43, the first to third exhaust temperature sensors 24, 26, and 30, the accelerator opening sensor 45, and the like. This is performed based on various types of data.

  Specifically, in the filter regeneration control, a differential pressure ΔP before and after the filter 28 is calculated based on both exhaust pressures that are parameter values detected by the first and second exhaust pressure sensors 27 and 29. The particulate amount is calculated based on the differential pressure ΔP. When the particulate amount becomes a predetermined amount or more, the fuel injection valve 9 is operated in the expansion stroke or the exhaust stroke, the fuel is post-injected, and fuel (unburned fuel) is supplied to the catalytic converter 25. Filter regeneration control is executed. In this filter regeneration control, the fuel injection amount and the fuel injection timing are set according to the operating state of the engine 1.

  Specifically, the regeneration of the filter 28 is performed in the following procedure. That is, first, when the particulate amount is greater than or equal to the first predetermined amount, after the main injection of fuel into the combustion chamber 6 in the vicinity of the compression stroke top dead center, the fuel injection valve 9 in the subsequent expansion stroke or exhaust stroke. Thus, fuel is injected into the combustion chamber 6 (post injection). The fuel injected into the combustion chamber 6 by this post-injection flows into the catalytic converter 25 in an unburned state. In the catalytic converter 25, the catalytic action of the oxidation catalyst 25a oxidizes the fuel (HC) to generate reaction heat, and this reaction heat raises the exhaust gas temperature. This hot exhaust gas flows into the filter 28 and heats the filter 28. As a result, the particulates collected in the filter 28 are burned and the filter 28 is regenerated. The ignition temperature of the particulate is 600 ° C., for example. When the particulate amount of the filter 28 becomes equal to or less than the second predetermined amount, the post-injection of the fuel injection valve 9 is stopped and the regeneration of the filter 28 is finished.

  Next, the outline of the control method of the fuel shortage avoidance control will be described with reference to FIG. In this fuel shortage avoidance control, the warning light 50 is turned on when the remaining amount of fuel (the remaining amount of fuel in the fuel tank 36) detected by the remaining fuel sensor 42 falls below the first set value, and the driver Visible warning is issued. Thereafter, when the remaining amount of fuel falls below the second set value, which is smaller than the first set value, the fuel injection of the fuel injection valve 9 becomes irregular, and the driver feels such as a change in vibration. A stronger warning is issued that can be done.

  When the fuel remaining amount is equal to or smaller than the second set value, the regeneration of the filter 28 is not executed even if the particulate amount is equal to or greater than the first predetermined amount. Also, if the filter 28 is being regenerated at the time when the remaining fuel amount falls below the second set value, the regeneration of the filter 28 is interrupted or stopped. That is, when the fuel injection is irregular, the regeneration of the filter 28 is interrupted or prohibited. Further, when the remaining amount of fuel decreases below the third set value which is smaller than the second set value, the main injection of the fuel injection valve 9, that is, the fuel injection for generating the power of the engine 1 (all fuel injections) is performed. The engine 1 is stopped and the engine 1 is forcibly stopped.

  Hereinafter, a specific control method of fuel injection control or filter regeneration control and fuel shortage avoidance control according to the present invention will be described with reference to the flowcharts shown in FIGS. 4 and 5. When control is started (start), first, in step S1, various data (various signals) detected by the sensors 16, 20, 21, 24, 26, 27, 29, 30, 42 to 45 are read. Further, necessary control information such as the engine speed N, the differential pressure ΔP before and after the filter 28, and the like are calculated from these detection data. Subsequently, in step S2, based on the differential pressure ΔP before and after the filter 28, the particulate amount PM, that is, the amount of particulates collected in the filter 28 is calculated.

  Next, in step S3, it is determined whether or not the remaining amount of fuel, that is, the remaining amount of fuel in the fuel tank 36 is equal to or less than the first set value a. Here, if it is determined that the remaining amount of fuel exceeds the first set value a (NO), that is, if the fuel in the fuel tank 36 has not decreased so much, the filters in steps S12 to S18 are performed. A regeneration control routine is executed.

  In this filter regeneration control routine, first, in step S12, it is determined whether or not the particulate amount PM is greater than or equal to a preset first predetermined amount (upper limit value). The first predetermined amount is set to such a value that, for example, when the particulate amount PM becomes larger than this, the exhaust gas flow path is narrowed or clogged, and the exhaust gas flow is substantially hindered. Is set.

  If it is determined in step S12 that the particulate amount PM is greater than or equal to the first predetermined amount (YES), 1 is set in the regeneration flag in step S13. This regeneration flag is a flag that is set to 1 when the regeneration of the filter 28 is being performed, and is reset to 0 when the regeneration of the filter 28 is completed. In step S14, the filter 28 is regenerated (regeneration control). The regeneration method of the filter 28 is as described above. Thereafter, the control returns to step S1 (return).

  On the other hand, when it is determined in step S12 that the particulate amount PM is less than the first predetermined amount (NO), in step S15, the particulate amount PM is equal to or less than a preset second predetermined amount (lower limit value). It is determined whether or not. The second predetermined amount is, for example, a value that can be considered that particulates have been sufficiently removed, and that exhaust gas flow path narrowing or clogging has been almost completely eliminated, for example, near 0 or 0. Is set.

  If it is determined in step S15 that the particulate amount PM exceeds the second predetermined amount (NO), it is determined in step S16 whether or not the regeneration flag is 1. If the regeneration flag is 1 (YES), the regeneration of the filter 28 is started, but the particulates are not sufficiently removed. Therefore, the regeneration of the filter 28 is continued in step S14, and then the step Return to S1. On the other hand, if the regeneration flag is not 1 (NO), that is, if the regeneration flag is 0, the regeneration of the filter 28 has not started yet, so step S14 is skipped and the process returns to step S1.

  If it is determined in step S15 that the particulate amount PM is equal to or smaller than the second predetermined amount (YES), since the particulate has already been sufficiently removed, the regeneration flag is returned to 0 in step S17, In step S18, the regeneration of the filter 28 is stopped (end of regeneration control). Thereafter, the control returns to step S1.

  By the way, if it is determined in step S3 that the remaining fuel amount is equal to or less than the first set value a (YES), the warning lamp 50 is turned on in step S4. By turning on the warning lamp 50, the driver can know that the remaining amount of fuel has decreased. That is, the driver is urged to refuel at a fueling stand or the like.

  Subsequently, in step S5, it is determined whether or not the remaining amount of fuel is equal to or less than a second set value b that is smaller than the first set value a. Here, when it is determined that the remaining fuel amount exceeds the second set value b (NO), the fuel injection from the fuel injection valve 9 is not irregular for the time being, so that the regeneration of the filter 28 is particularly prohibited. There is no need. Therefore, the filter regeneration control routine of steps S12 to S18 is executed.

  On the other hand, if it is determined in step S5 that the remaining fuel amount is equal to or less than the second set value b (YES), it is determined in step S6 whether or not the regeneration flag is 1. If it is determined that the regeneration flag is 1 (YES), the regeneration flag is returned to 0 in step S7. Subsequently, in step S8, regeneration of the filter 28 being performed is interrupted or stopped. After step S9 is executed. That is, since the fuel remaining amount is equal to or less than the second set value b, fuel injection from the fuel injection valve 9 is made irregular in step S11 described later. Therefore, in order to avoid the regeneration of the filter 28 when the fuel injection is irregular, the regeneration of the filter 28 is interrupted or stopped in steps S7 and S8. If it is determined in step S6 that the regeneration flag is not 1 (0) (NO), steps S7 and S8 are skipped and step S9 is executed.

  In step S9, it is determined whether or not the remaining amount of fuel is equal to or smaller than a third set value c that is smaller than the second set value b. Here, when it is determined that the remaining fuel amount exceeds the third set value c (NO), that is, when the remaining fuel amount is equal to or less than the second set value and exceeds the third set value, The fuel injection from the fuel injection valve 9 is made irregular (irregular control).

  Specifically, in step S11, for example, the fuel injection of the fuel injection valve 9 of a part of the cylinders of the engine 1 (for example, one cylinder) is intermittently reduced or stopped, or is always reduced or stopped. . As a result, the operating state of the engine 1 is different from the normal state. For example, the vibration of the engine 1 becomes larger than in a normal operating state. Therefore, the driver is more strongly encouraged to refuel at a fueling station or the like than a warning by a simple warning lamp 50. As described above, when the fuel injection is irregular in this way, the regeneration of the filter 28 is not performed.

  On the other hand, when it is determined in step S9 that the remaining fuel amount is equal to or less than the third set value c (YES), the main injection of the fuel injection valve 9, that is, the fuel injection for generating the power of the engine 1 is stopped. The engine 1 is forcibly stopped (engine stop control). As a result, it is reliably prevented that the fuel runs out. In this case, for example, the driver can start the engine 1 by continuing to receive the fuel necessary for traveling to the nearest gas station from the passing vehicle, and can continue the traveling of the vehicle.

  As described above, according to the first embodiment of the present invention, when the remaining fuel amount falls below the second set value, the fuel injection of the fuel injection valve 9 is made irregular. In this way, the fuel injection is made irregular. When this is done, regeneration of the filter 28 is interrupted or prohibited. For this reason, the exhaust gas temperature control is not disturbed, or the exhaust gas temperature becomes unstable, and thus the incomplete regeneration of the filter 28 occurs. For example, the exhaust gas becomes abnormally hot and the filter 28 is damaged. On the contrary, it is possible to effectively prevent the temperature of the exhaust gas from rising sufficiently and the particulates from being burnt or removed insufficiently. Further, when the remaining amount of fuel becomes equal to or less than the third set value, fuel injection is stopped. Therefore, the engine 1 is forcibly stopped before there is no fuel in the fuel tank 36. It is possible to reliably prevent the engine 1 from starting and becoming impossible.

(Embodiment 2)
The second embodiment of the present invention will be described below. However, the mechanical or configuration of the diesel engine according to the second embodiment is the same as that of the first embodiment, and only the control methods of the filter regeneration control and the fuel shortage avoidance control are different. Therefore, hereinafter, only the control method of the filter regeneration control and the fuel shortage avoidance control in the second embodiment will be described with reference to FIGS. The basic parts of the control method for filter regeneration control and fuel shortage avoidance control according to Embodiment 2 are the same as the control method for filter regeneration control and fuel shortage avoidance control according to Embodiment 1. For this reason, below, a different part from the control method of filter regeneration control and fuel shortage avoidance control mainly concerning Embodiment 1 is explained.

  The differences between the filter regeneration control and the fuel exhaustion avoidance control according to the first embodiment in the filter regeneration control and the fuel exhaustion avoidance control according to the second embodiment are as follows. That is, as described above, in the first embodiment, when the remaining fuel amount is equal to or less than the first set value a and exceeds the second set value b, the particulate amount is equal to or greater than the first predetermined amount. Normal filter regeneration control similar to the case where the remaining amount of fuel is sufficient, such as regeneration of the filter 28, is performed. On the other hand, in the second embodiment, when the remaining amount of fuel drops below the first set value a and the warning lamp 50 is turned on, even if the particulate amount PM is less than the first predetermined amount, At that time, the regeneration of the filter 28 is forcibly started (forced regeneration). That is, the regeneration of the filter 28 is started regardless of the particulate amount PM. Other points are the same as those in the first embodiment.

  As shown in FIGS. 6 and 7, the control contents or process contents of steps S21 to S31 in the second embodiment are the same as (or the same as) the control contents or process contents of steps S1 to S11 in the first embodiment, respectively. It is. In the second embodiment, the control contents or process contents in steps S39 to S45 are the same as (or the same as) the control contents or process contents in steps S12 to S18 in the first embodiment, respectively.

  However, when it is determined in step S25 that the remaining amount of fuel exceeds the second set value b (NO), that is, when the remaining amount of fuel is equal to or less than the first set value a and the warning lamp 50 is turned on, Steps S32 to S38 are executed, and forced regeneration (forced regeneration) of the filter 28 is performed. Specifically, first, at step S32, it is determined whether or not the forced regeneration end flag is 1.

  This forced regeneration end flag is a flag that is set to 1 when the forced termination ends after the fuel remaining amount is equal to or less than the first set value a and the forced regeneration of the filter 28 is started. This forced regeneration end flag indicates that the filter 28 is in a state where fuel is supplied after the remaining amount of fuel becomes equal to or less than the first set value a (the amount of fuel that exceeds the first set value a). This is a flag for avoiding the forced regeneration being repeatedly performed (the forced regeneration is performed only once during this period). Note that the forced regeneration end flag is returned to 0 in step S46 when the amount of fuel remaining has exceeded the first set value a.

  If it is determined in step S32 that the forced regeneration flag is 1 (YES), the forced regeneration of the filter 28 has already been completed, so steps S33 to S38 are skipped and the process returns to step S21 (return). . On the other hand, if it is determined in step S32 that the forced regeneration flag is not 1 (that is, 0) (NO), it is determined in step S33 whether the particulate amount PM is equal to or smaller than the second predetermined amount. . If it is determined that the particulate amount PM exceeds the second predetermined amount (NO), 1 is set in the regeneration flag in step S34, and then the forced regeneration of the filter 28 is performed in step S35. (Forced regeneration control). The method of forced regeneration of the filter 28 is the same as that in the normal regeneration process in step S41 (ie, step S14). Thereafter, the control returns to step S21.

  If it is determined in step S33 that the particulate amount PM is equal to or smaller than the second predetermined amount (YES), since the particulate has already been sufficiently removed, the regeneration flag is returned to 0 in step S36, In step S37, the forced regeneration of the filter 28 is stopped (end of regeneration control). Next, in step S38, 1 is set to the forced regeneration end flag. Thereafter, the control returns to step S21.

  Thus, according to the second embodiment, basically, as in the case of the first embodiment, the exhaust gas temperature control is not disturbed, or the exhaust gas temperature is unstable, and thus an incomplete or abnormal filter. 28, for example, the exhaust gas becomes abnormally hot and the filter 28 is damaged. Conversely, the exhaust gas temperature does not rise sufficiently and the particulates are not sufficiently burned or removed. Can be effectively prevented. In addition, it is possible to reliably prevent the engine 1 from being forcibly stopped before the fuel in the fuel tank 36 runs out, and the engine 1 from being started due to air entering the fuel supply system.

  Further, when the remaining amount of fuel is equal to or less than the first set value a and the warning lamp 50 is turned on, the filter 28 is forcibly regenerated regardless of the particulate quantity PM. Before the regeneration of 28 is prohibited, the filter 28 can be regenerated in advance to prevent or suppress the particulate amount PM from exceeding the first predetermined amount when the remaining amount of fuel is low. it can. That is, the regeneration of the filter 28 during engine operation is possible as much as possible.

It is a mimetic diagram showing the system configuration of the engine system provided with the diesel engine concerning the present invention, and its control device. It is a block diagram which shows the structure of the control mechanism of the engine system shown in FIG. It is a schematic diagram which shows the outline | summary of fuel shortage avoidance control. It is a flowchart which shows a part of control method of filter regeneration control and fuel shortage avoidance control concerning Embodiment 1 of this invention. It is a flowchart which shows a part of control method of filter regeneration control and fuel shortage avoidance control concerning Embodiment 1 of this invention. It is a flowchart which shows a part of control method of filter regeneration control and fuel shortage avoidance control concerning Embodiment 2 of this invention. It is a flowchart which shows a part of control method of filter regeneration control and fuel shortage avoidance control concerning Embodiment 2 of this invention.

Explanation of symbols

E engine system, C control unit, 1 diesel engine (engine), 2 cylinder head, 3 cylinder block, 4 intake valve, 5 intake port, 6 combustion chamber, 7 cylinder (cylinder), 8 piston, 9 fuel injection valve, 10 Exhaust valve, 11 Exhaust port, 12 Connecting rod, 13 Crankshaft, 14 Intake passage, 14a Independent intake passage, 15 Air cleaner, 16 Air flow sensor, 17 Turbocharger, 17a Compressor, 17b Turbine, 18 Intercooler, 19 Intake throttle valve, 20 Intake temperature sensor, 21 Intake pressure sensor, 22 Surge tank, 23 Exhaust passage, 24 First exhaust temperature sensor, 25 Catalytic converter, 25a Oxidation catalyst, 26 Second exhaust temperature sensor, 27 First exhaust pressure sensor, 28 Diesel particulate Filter (Fi 29) second exhaust pressure sensor, 30 third exhaust temperature sensor, 31 EGR passage, 32 EGR cooler, 33 EGR control valve, 36 fuel tank, 37 fuel passage, 38 fuel filter assembly, 39 high pressure fuel pump (FIP) , 40 common rail, 41 common rail pressure sensor, 42 fuel remaining amount sensor, 43 crank angle sensor (engine speed sensor), 44 water temperature sensor, 45 accelerator opening sensor, 50 warning light.

Claims (3)

A filter that collects particulates in exhaust gas discharged from the engine;
An oxidation catalyst that heats the filter by accelerating the oxidation reaction of the fuel in the exhaust gas and raising the temperature of the exhaust gas;
Parameter detection means for detecting a parameter related to the amount of collected particulate matter of the filter;
When it is determined that the particulate collection amount of the filter is equal to or greater than a predetermined amount based on the above parameters, the filter is regenerated by injecting fuel for filter regeneration into the fuel injection means and supplying the fuel to the oxidation catalyst. A control device for a diesel engine comprising regeneration control means for performing,
A remaining amount detecting means for detecting the remaining amount of fuel in the fuel tank;
Combustion control means for making the fuel injection amount of the fuel injection means irregular when the remaining amount of fuel detected by the remaining amount detection means falls below a set value;
The control device for a diesel engine, wherein the regeneration control means is configured to interrupt or prohibit the regeneration of the filter when the fuel injection amount is irregularized by the combustion control means. Warning means for turning on a warning lamp when the remaining amount of fuel in the fuel tank falls below the first set value is provided,
The combustion control means makes the fuel injection amount of the fuel injection means irregular when the remaining amount of fuel falls below a second set value that is smaller than the first set value.
2. The regeneration means according to claim 1, wherein when the warning light is turned on, the regeneration of the filter is started even if the particulate collection amount of the filter is less than the predetermined amount. Diesel engine control device. The combustion control means is configured to stop injection of fuel for generating engine power when the remaining amount of fuel becomes equal to or smaller than a third set value that is smaller than the second set value. The diesel engine control device according to claim 2.

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