JP2010077830A - Fuel system cleaning device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clean deposits adhered to a fuel system component without effecting the combustion and exhaust performance of an internal combustion in a fuel system cleaning device for an internal combustion engine that introduces a cleaning solvent into a fuel system of the internal combustion engine and performs cleaning. <P>SOLUTION: This fuel system cleaning device is equipped with a fuel tank 16 for storing biofuel, a fuel pipe for supplying the biofuel in the fuel tank 16 to a diesel engine 10, a cleaning solvent tank 32 for storing a cleaning solvent, an introduction pipe 34 for making one end of a section to be cleaned of the fuel pipe selectively communicate with the cleaning solvent tank 32, and a return pipe 36 for making the other end of the section to be cleaned of the fuel pipe selectively communicate with the cleaning solvent tank 32. When cleaning the fuel system of the diesel engine 10, communicating destinations of both ends of the section to be cleaned are switched to the introduction pipe 34 and the return pipe 36 and a circulating path is formed, and the cleaning solvent introduced to the section to be cleaned is recirculated to the cleaning solvent tank 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel system cleaning apparatus for an internal combustion engine, and more particularly to a fuel system cleaning apparatus for an internal combustion engine that performs cleaning by introducing a cleaning solvent into the fuel system of the internal combustion engine.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-16662, there is known a cleaning agent addition apparatus that adds a cleaning agent for purifying deposits attached to an injection hole portion of a fuel injection valve to fuel. . In this apparatus, a reservoir for the detergent is provided separately from the fuel tank. The detergent supply passage extending from the reservoir is connected to the fuel supply passage from the fuel tank to the fuel injection valve. And according to the estimated amount of deposit adhering to a nozzle hole part, it has a structure which supplies a cleaning agent to a fuel supply flow path. Thereby, while suppressing the deterioration of the fuel-injection performance by deposit adhesion, the bad influence by excessive administration of a detergent can be suppressed.

JP 2007-16664 A JP 2001-317435 A JP 2000-199464 A

  By the way, there is a demand to use biofuels generated from various vegetable oils, plant materials, and the like as fuels for internal combustion engines. However, since biofuel has a large characteristic change (increased viscosity) due to oxidative degradation, there is a problem that deposits are easily deposited on fuel system parts such as an injection valve, a fuel pump, and a fuel filter. For this reason, it is also assumed that deposits adhering to the fuel system parts cannot be sufficiently cleaned with a conventional apparatus that cleans the fuel system parts by adding a cleaning solvent to the fuel. Therefore, in order to enhance the cleaning effect of these deposits, it is conceivable to add a high concentration cleaning solvent or increase the amount of cleaning solvent added. However, in the conventional cleaning apparatus in which the added cleaning solvent is burned in the engine together with the fuel, there is a possibility that the combustion state and the exhaust performance may be adversely affected.

  The present invention has been made to solve the above-described problems, and is a fuel for an internal combustion engine that can clean deposits adhering to fuel system parts without affecting the combustion and exhaust performance of the internal combustion engine. An object of the present invention is to provide a system cleaning apparatus.

In order to achieve the above object, a first invention is a fuel system cleaning device for an internal combustion engine,
A fuel tank for storing fuel used for combustion of the internal combustion engine;
A fuel pipe for supplying fuel in the fuel tank to the internal combustion engine;
A cleaning solvent tank for storing the cleaning solvent;
An introduction pipe for selectively communicating one end of a section to be cleaned of the fuel pipe and the cleaning solvent tank;
A return pipe for selectively communicating the other end of the cleaning target section and the cleaning solvent tank;
Circulation that forms a circulation path for circulating the cleaning solvent in the cleaning solvent tank by switching the communication destination of the section to be cleaned to the introduction pipe and the return pipe when cleaning the fuel system of the internal combustion engine A route forming means;
A fuel system cleaning means for cleaning the fuel system by circulating a cleaning solvent in the circulation path;
It is characterized by providing.

According to a second invention, in the first invention,
The circulation path forming means includes
First switching means for switching a communication destination at one end of the cleaning target section between the introduction pipe side and the fuel pipe side;
Second switching means for switching the communication destination at the other end of the section to be cleaned between the return pipe side and the fuel pipe side;
When cleaning the fuel system, the first switching means switches the communication destination at one end of the cleaning target section to the introduction pipe side, and the second switching means sets the communication destination at the other end of the cleaning target section. Control means for switching to the return pipe side;
It is characterized by including.

According to a third invention, in the first or second invention,
Fuel system parts are arranged in the section to be cleaned.

According to a fourth invention, in the third invention,
The fuel system component includes a fuel pump for pumping the fuel in the fuel tank to the fuel injection valve,
The fuel system cleaning means circulates a cleaning solvent in the circulation path using a driving force of the fuel pump.

According to a fifth invention, in any one of the first to fourth inventions,
The fuel pipe includes a fuel return pipe for returning the fuel not injected by the fuel injection valve to the fuel tank,
The other end of the cleaning target section is provided in the middle of the fuel return pipe.

A sixth invention is any one of the first to fifth inventions,
The cleaning solvent tank is arranged at a position where the liquid level of the cleaning solvent tank is always lower than the liquid level of the fuel tank.

A seventh invention is the invention according to any one of the first to sixth inventions,
The fuel system cleaning means is characterized in that after introducing the cleaning solvent into the circulation path, the circulation of the cleaning solvent is temporarily stopped and left for a predetermined period.

According to an eighth invention, in any one of the first to seventh inventions,
The fuel system cleaning means further includes prohibiting means for prohibiting starting of the internal combustion engine during execution of the fuel system cleaning means.

According to a ninth invention, in any one of the first to seventh inventions,
A second fuel pipe for supplying fuel in the fuel tank to the internal combustion engine;
Second fuel supply means for supplying the fuel in the fuel tank to the internal combustion engine via the second fuel pipe during execution of the fuel system cleaning means;
Is further provided.

In a tenth aspect of the present invention based on any one of the first to ninth aspects,
The fuel system cleaning device further includes a replacement unit that replaces the cleaning solvent flowing in the cleaning target section with the fuel in the fuel tank when a stop request for the fuel system cleaning unit is issued.

In an eleventh aspect based on the tenth aspect,
The replacement means switches the communication destination at the other end of the cleaning target section from the return pipe side after a predetermined time has elapsed after switching the communication destination at one end of the cleaning target section from the introduction pipe side to the fuel pipe side. It switches to the said fuel piping side, It is characterized by the above-mentioned.

A twelfth aspect of the invention is any one of the first to eleventh aspects of the invention,
The fuel supplied to the internal combustion engine is biofuel,
Means for estimating the amount of deposits attached to the fuel system based on the concentration of biofuel and the operating state of the internal combustion engine;
Determination means for determining whether or not the fuel system needs to be cleaned based on the amount of deposit;
Is further provided.

In a thirteenth aspect of the present invention based on any one of the first to twelfth aspects of the invention,
The fuel cell system further comprises second determination means for determining that the fuel system needs to be cleaned when a start failure of the internal combustion engine occurs.

In a fourteenth aspect of the present invention based on any one of the first to thirteenth aspects,
The apparatus further comprises second prohibiting means for prohibiting execution of the fuel system cleaning means when the amount of the cleaning solvent in the cleaning solvent tank is smaller than a predetermined reference value.

In a fifteenth aspect of the invention, any one of the first to fourteenth aspects of the invention,
It further comprises a third prohibiting means for prohibiting execution of the fuel system cleaning means when the cleaning solvent temperature exceeds a predetermined reference range.

In a sixteenth aspect of the present invention based on any one of the first to fifteenth aspects,
The fuel cell cleaning apparatus further includes fourth prohibiting means for prohibiting execution of the fuel system cleaning means when the amount of time change of the cleaning solvent amount in the cleaning solvent tank exceeds a predetermined reference range.

A seventeenth aspect of the invention is any one of the first to sixteenth aspects of the invention,
The fuel system cleaning means further comprises third determination means for determining that the cleaning solvent needs to be replaced when the integrated value of execution times of the fuel system cleaning means is larger than a predetermined reference value.

According to an eighteenth aspect of the invention, in any one of the first to seventeenth aspects of the invention,
When the amount of the cleaning solvent in the cleaning solvent tank exceeds a predetermined reference amount, a cleaning solvent supply means is further provided for supplying the cleaning solvent to the internal combustion engine within a range that does not affect the combustion state of the internal combustion engine. It is characterized by that.

In a nineteenth aspect of the present invention based on any one of the first to eighteenth aspects of the invention,
In a hybrid vehicle comprising the internal combustion engine and another output device,
In the case where an output request to the hybrid vehicle is issued during the execution of the fuel system cleaning means, an alternative means for driving the other output device in place of the internal combustion engine is further provided.

  According to the first invention, when the fuel system of the internal combustion engine is cleaned, the communication destinations at both ends of the section to be cleaned in the fuel pipe are switched to the introduction pipe and the return pipe. As a result, a cleaning solvent circulation path including a cleaning solvent tank, an introduction pipe, a cleaning target section, a return pipe, and a cleaning solvent tank is formed. Therefore, according to the present invention, the cleaning solvent flowing through the circulation path can be refluxed to the cleaning solvent tank, so that the cleaning of the fuel pipe is avoided while avoiding the situation where the cleaning solvent burns and the exhaust performance deteriorates. Deposits adhering to the target section can be cleaned.

  According to the second aspect of the invention, the circulation path forming means includes the first switching means for switching the communication destination at one end of the cleaning target section between the fuel pipe side and the introduction piping side, and the other end of the cleaning target section. Second switching means for switching the communication destination between the fuel pipe side and the return pipe side. For this reason, according to the present invention, when the fuel system is cleaned, the switching path is controlled to form a circulation path constituted by the introduction pipe, the return pipe, and the section to be cleaned.

  According to the third invention, the fuel system parts are arranged in the section to be cleaned. Therefore, according to the present invention, these fuel system parts can be effectively cleaned by the fuel system cleaning means.

  According to the fourth aspect, the cleaning solvent is circulated using the driving force of the fuel pump. For this reason, according to the present invention, it is possible to circulate the cleaning solvent without providing a separate drive source for circulating the cleaning solvent.

  According to the fifth invention, the other end of the section to be cleaned is provided in the middle of the fuel return pipe. That is, the return pipe is connected in the middle of the fuel return pipe as the other end of the cleaning target section, and selectively connects the cleaning target section side of the fuel return pipe and the cleaning solvent tank. For this reason, according to the present invention, since the fuel pipe path to the fuel injection valve, the fuel injection valve, and the fuel return pipe can be included as objects to be cleaned, the fuel system can be cleaned widely.

  According to the sixth aspect of the invention, the cleaning solvent tank is arranged at a position where the liquid level of the cleaning solvent tank is always lower than the liquid level of the fuel tank. Therefore, according to the present invention, even if an abnormality occurs in the communication state between the cleaning target section and the introduction pipe or the return pipe, the cleaning solvent in the cleaning solvent tank flows into the fuel tank due to the negative pressure in the pipe. It is possible to effectively suppress such a situation.

  According to the seventh invention, when cleaning the fuel system, after introducing the cleaning solvent into the circulation path, the circulation of the cleaning solvent is stopped once and left for a predetermined period. If the inside of the circulation path is filled with the cleaning solvent, a certain degree of cleaning effect can be exhibited even if the cleaning solvent is not circulated. For this reason, according to this invention, the power consumption of the drive source for circulating a washing | cleaning solvent can be suppressed effectively.

  According to the eighth invention, the start of the internal combustion engine is prohibited during the cleaning of the fuel system. Therefore, according to the present invention, it is possible to effectively avoid the situation where the cleaning solvent circulating in the fuel pipe is supplied to the internal combustion engine.

  According to the ninth aspect, during the cleaning of the fuel system, the fuel is supplied to the internal combustion engine via the second fuel pipe. Therefore, according to the present invention, the fuel system can be cleaned even during operation of the internal combustion engine.

  When cleaning is stopped with the cleaning solvent remaining in the cleaning target section, when the fuel supply to the internal combustion engine is resumed, the cleaning solvent remaining in the cleaning target section is supplied to the internal combustion engine. End up. According to the tenth invention, when a stop request for cleaning of the fuel system is issued, the section to be cleaned is replaced with the fuel in the fuel tank. For this reason, according to this invention, when the fuel supply to an internal combustion engine is restarted, the situation where a washing | cleaning solvent is supplied to an internal combustion engine can be avoided effectively. Thereby, the deposit adhering to the cleaning target section of the fuel pipe can be cleaned while avoiding the situation where the cleaning solvent burns and the exhaust performance deteriorates.

  According to the eleventh aspect, after a predetermined time has elapsed since the communication destination at one end of the cleaning target section is switched from the introduction pipe side to the fuel pipe side, the communication destination at the other end of the cleaning target section is changed from the return pipe side. Switch to the fuel piping side. When the communication destination on the introduction pipe side is switched to the fuel pipe side, the fuel in the fuel tank is replaced by the section to be cleaned. For this reason, according to the present invention, the inside of the section to be cleaned can be efficiently replaced with the fuel in the fuel tank.

  According to the twelfth aspect, in the internal combustion engine to which the biofuel is supplied, it is determined whether or not the fuel system needs to be cleaned based on the estimated deposit amount on the fuel system. The amount of deposit attached to the fuel system can be estimated based on the concentration of the biofuel and the operating state of the internal combustion engine. For this reason, according to the present invention, it is possible to determine whether or not the fuel system needs to be cleaned based on the estimated deposit amount.

  When the start failure of the internal combustion engine has occurred, there is a high possibility that the fuel system is clogged. For this reason, according to the thirteenth aspect, it is possible to determine that the fuel system needs to be cleaned when a start failure of the internal combustion engine occurs.

  When the amount of the cleaning solvent in the cleaning solvent tank is smaller than a predetermined reference value, the cleaning solvent for circulating in the circulation path becomes insufficient. According to the fourteenth aspect, when the amount of the cleaning solvent in the cleaning solvent tank is smaller than the predetermined reference value, cleaning of the fuel system is prohibited. For this reason, according to the present invention, it is possible to effectively avoid the situation where air is sucked into the circulation path.

  The cleaning effect of the cleaning solvent is significantly reduced at extremely low temperatures. On the other hand, when the temperature is extremely high, the reflux performance decreases due to the generation of vapor. According to the fifteenth aspect, when the temperature of the cleaning solvent exceeds a predetermined reference range, cleaning of the fuel system is prohibited. For this reason, the situation where the washing | cleaning which does not have a desired washing | cleaning effect is performed can be avoided effectively.

  When the amount of the cleaning solvent in the cleaning solvent tank suddenly increases, the fuel in the fuel tank may flow into the cleaning solvent tank. In addition, when the amount of the cleaning solvent rapidly decreases, there is a possibility that the cleaning solvent in the cleaning solvent tank flows into the fuel tank. According to the sixteenth aspect, when the amount of change in the amount of the cleaning solvent in the cleaning solvent tank with time exceeds a predetermined reference range, cleaning of the fuel system is prohibited. For this reason, according to this invention, the situation where the cleaning which does not have a desired cleaning effect is performed can be avoided effectively.

  According to the seventeenth aspect, when the integrated value of the execution time of the fuel system cleaning means is greater than the predetermined reference value, it is determined that the cleaning solvent needs to be replaced. As the washing solvent circulates in the circulation path, the concentration of the polymer in the washing solvent increases. Therefore, according to the present invention, it is possible to appropriately determine the replacement time of the cleaning solvent based on the integrated value of the execution time of the fuel system cleaning means.

  According to the eighteenth aspect, when the amount of cleaning solvent in the cleaning solvent tank exceeds a predetermined reference amount, the cleaning solvent is supplied to the internal combustion engine within a range that does not affect the combustion state of the internal combustion engine. For this reason, according to the present invention, it is possible to keep the amount of the cleaning solvent optimal while maintaining a good combustion state of the internal combustion engine.

  According to the nineteenth aspect of the invention, in a hybrid vehicle including an internal combustion engine and another output device, when an output request is issued to the hybrid vehicle during cleaning of the fuel system, another output is used instead of the internal combustion engine. The device is driven. For this reason, according to the present invention, the fuel system can be cleaned while satisfying the output requirement for the vehicle.

  Several embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted. The present invention is not limited to the following embodiments.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
FIG. 1 is a diagram for explaining the configuration of a system according to an embodiment of the present invention. As shown in this figure, the system of the present embodiment includes a multi-cylinder type diesel engine 10 mounted on an automobile. Each cylinder 12 of the diesel engine 10 is provided with a direct injection type fuel injection valve 14 for injecting fuel into the cylinder. The diesel engine 10 burns the fuel injected from the fuel injection valve 14 in the cylinder 12 together with the intake air, and rotates the crankshaft by the torque generated during the combustion.

  The diesel engine 10 of the present embodiment includes a fuel tank 16, a fuel pump 18, and a common rail 20 for storing fuel. In the fuel tank 16, for example, 100% biofuel such as rapeseed methyl ester (RME), or a mixed fuel in which such biofuel and light oil are mixed in a predetermined ratio (hereinafter referred to as these) Are collectively referred to as “biofuel”).

The fuel pump 18 is constituted by an electric pump or the like, and its suction port is connected to the fuel tank 16 by a suction pipe 22. In the middle of the suction pipe 22, a filter 30 is provided for collecting a product (polymerized product) and the like generated by oxidative degradation of the biofuel.
Furthermore, a bio-concentration sensor 42 for detecting a biofuel concentration (RME concentration) in the fuel flowing through the inside is incorporated on the upstream side of the suction pipe 22. The discharge port of the fuel pump 18 is connected to the common rail 20 by a discharge pipe 24. The fuel pump 18 sucks the fuel in the fuel tank 16 and discharges it toward the common rail 20.

  The common rail 20 is a fuel supply pipe called a delivery pipe, and supplies the fuel discharged from the fuel pump 18 to the fuel injection valve 14 of each cylinder 12. For this reason, each fuel injection valve 14 is connected to the common rail 20 via a connection pipe 26. Further, a fuel return pipe 28 is provided between the common rail 20 and the fuel tank 16 for returning the surplus fuel in the common rail 20 to the fuel tank 16.

  The fuel return pipe 28 is partially branched and connected to the outflow side of the fuel injection valve 14. Excess fuel that has not been injected from the fuel injection valve 14 is returned into the fuel tank 16 via the fuel return pipe 28.

  Next, the characteristic configuration of the present embodiment will be described in detail. As shown in FIG. 1, the system according to the present embodiment includes a cleaning solvent tank 32 for storing a cleaning solvent. In the washing solvent, an organic solvent such as ethanol is stored as a solvent for dissolving the polymer. One end of an introduction pipe 34 is connected to the cleaning solvent tank 32. Further, the other end of the introduction pipe 34 is connected to the upstream side of the filter 30 in the suction pipe 22 described above. A switching valve 44 is disposed at a connection portion between the introduction pipe 34 and the suction pipe 22. The switching valve 44 is connected to the suction pipe 22 side (hereinafter referred to as “A side”) communicating with the fuel tank 16 and the introduction pipe 34 side (hereinafter referred to as “B” hereinafter) communicating with the cleaning solvent tank 32. A valve for switching between the two sides.

  One end of a return pipe 36 is connected to the discharge pipe 24. The other end of the return pipe 36 is connected to the cleaning solvent tank 32 described above. A switching valve 46 is disposed at a connection portion between the discharge pipe 24 and the return pipe 36. The switching valve 46 is connected to the suction pipe 22 side (hereinafter referred to as “A side”) communicating with the common rail 20 and the return pipe 36 side (hereinafter referred to as “B side”) communicating with the cleaning solvent tank 32. ”).

  As shown in FIG. 1, the control device of the present embodiment includes an ECU (Electronic Control Unit) 40. As an input to the ECU 40, in addition to the bio-concentration sensor 42 described above, a level sensor 48 for detecting the liquid level of the cleaning solvent tank 32 and various sensors (not shown) for detecting the operating state of the diesel engine 10. Is connected. Further, the above-described fuel pump 18 and various actuators such as the switching valves 44 and 46 are connected to the output of the ECU 40.

[Operation of Embodiment 1]
Next, characteristic operations in the system of the present embodiment will be described. As described above, the diesel engine 10 of the present embodiment uses biofuel as its fuel. Biofuels have many components having unsaturated bonds, and tend to undergo oxidative degradation with time. For example, RME, which is a biofuel, has oleic acid methyl ester as a main component, but the main component has an unsaturated bond. For this reason, it undergoes oxidation to cause polymerization and the like, and a gum-like substance (polymer) having a large molecular weight and a high viscosity is produced. As a result, the gum-like polymer is deposited on the fuel system parts such as the fuel pump 18 and the filter 30, and the fuel flow path is clogged.

  In addition, the oxidative degradation of biofuel is more likely to proceed as the fuel temperature increases. In particular, the fuel in the fuel tank 16 is heated to a high temperature in the course of being supplied to the fuel injection valve 14. Excess fuel out of the fuel supplied to the fuel injection valve 14 is returned to the fuel tank 16 again through the fuel return pipe 28. For this reason, when this reflux operation is repeatedly executed, a polymer is easily generated.

  As a system for cleaning a fuel system, a system for cleaning a polymer deposited in a fuel system by adding a cleaning solvent to the fuel is conventionally known. However, in the above conventional system, the cleaning solvent added to the fuel is combusted together with the fuel in the internal combustion engine. For this reason, when the concentration of the cleaning solvent is increased in order to enhance the cleaning effect, there is a possibility that the combustion state and the exhaust performance are adversely affected.

  Therefore, the system of the present embodiment is configured to recirculate the cleaning solvent to the cleaning solvent tank 32 without burning it in the diesel engine 10. More specifically, in the system of the present embodiment, when the fuel system is washed, the switching valves 44 and 46 are switched to the B side, and the washing solvent tank 32 → the introduction pipe 34 → the suction pipe 22 → A cleaning solvent circulation path communicating with the filter 30 → the fuel pump 18 → the discharge pipe 24 → the return pipe 36 → the cleaning solvent tank 32 is formed. For this reason, by driving the fuel pump 18, the cleaning solvent in the cleaning solvent tank 32 can be circulated to efficiently clean the fuel system.

  When the fuel system is sufficiently cleaned, the cleaning operation is then stopped. More specifically, first, the switching valve 44 is switched to the A side. As a result, a path communicating with the fuel tank 16 → the suction pipe 22 → the filter 30 → the fuel pump 18 → the discharge pipe 24 → the return pipe 36 → the cleaning solvent tank 32 is formed. Then, by driving the fuel pump 18, the solvent in the path is gradually replaced from the cleaning solvent to the biofuel. When a time (for example, 1 minute) for replacing the inside of the path with biofuel elapses, the switching valve 46 is then switched to the A side. Thus, a fuel supply path communicating with the fuel tank 16 → the suction pipe 22 → the filter 30 → the fuel pump 18 → the discharge pipe 24 → the common rail 20 → the connection pipe 26 → the fuel injection valve 14 is formed, and the fuel supply path The whole can be replaced with biofuel. Therefore, when the engine is started, it is possible to avoid a situation in which the cleaning solvent flows to the fuel injection valve 14. Therefore, it is possible to effectively suppress the deterioration of the combustion state and the exhaust emission.

[Specific Processing in Embodiment 1]
Next, with reference to FIG. 2, the specific content of the process performed in this Embodiment is demonstrated. FIG. 2 is a flowchart of a routine executed by the ECU 40 for cleaning the fuel system. Note that the routine shown in FIG. 2 is executed when the diesel engine 10 is stopped.

  In the routine shown in FIG. 2, first, the bioconcentration X of the biofuel is detected (step 100). Here, specifically, it is detected based on the bio-concentration sensor 42. Next, a threshold value TLX is set (step 102). FIG. 3 shows a map defining the relationship between the bioconcentration X and the threshold value TLX. Specifically, the threshold value TLX corresponding to the bioconcentration X detected in step 100 is specified according to the map shown in FIG.

  Next, it is determined whether or not the operating time T1AX of the fuel pump 18 is greater than the threshold value TLX (step 104). The operating time T1AX indicates an integrated value of the operating time of the fuel pump 18 under the situation where the switching valve 44 is set to the A side. Specifically, the magnitude of the operating time T1AX stored in the ECU 40 and the threshold value TLX set in step 102 are compared. As a result, if the establishment of T1AX> TLX is not recognized, it is determined that the oxidation deterioration of the biofuel has not progressed, that is, the clogging of the polymer has not occurred in the fuel system parts, and this routine is promptly performed. Is finished.

  On the other hand, if the establishment of T1AX> TLX is confirmed in step 104 above, it is determined that the biofuel has undergone oxidative degradation and clogging of the polymer has occurred in the fuel path. Then, the cleaning solvent is circulated (step 106). Specifically, the fuel pump 18 is driven after the switching valves 44 and 46 are switched to the B side. As a result, the cleaning solvent in the cleaning solvent tank 32 is circulated through the filter 30 and the fuel pump 18.

  Next, it is determined whether or not a predetermined time has elapsed since the execution of the process of step 106 (step 110). Here, specifically, it is determined whether or not a time (for example, 1 minute) for sufficiently cleaning the fuel path has elapsed. As a result, if it is determined that the predetermined time has elapsed, it is determined that the fuel path has been sufficiently washed, and the process proceeds to the next step. First, the switching valve 44 is switched to the A side (step 112). .

  Next, it is determined whether or not a predetermined time has elapsed since the execution of the process of step 112 (step 114). Here, specifically, it is determined whether or not a time (for example, 1 minute) necessary for replacing the fuel path from the fuel tank 16 to the switching valve 46 with the biofuel has elapsed. As a result, when it is determined that the predetermined time has elapsed, the process proceeds to the next step, and the switching valve 46 is switched to the A side (step 116). Next, the fuel pump 18 is stopped (step 118).

  As described above, according to the system of the first embodiment, since the cleaning solvent can be circulated to the fuel system at a predetermined timing, the clogging of the polymer generated in the fuel path is effectively removed. Can do.

  Further, according to the system of the first embodiment, since the cleaning solvent is circulated into the cleaning solvent tank 32 through the return pipe 36, the cleaning solvent is not burned in the engine. For this reason, since the washing | cleaning solvent with a high density | concentration can be used, a cleaning effect can be heightened effectively.

  Further, according to the system of the first embodiment, after the cleaning solvent circulation path is replaced with biofuel, the system is switched to the normal fuel supply path. For this reason, since the situation where the cleaning solvent flows to the fuel injection valve 14 can be avoided, the deterioration of the combustion state of the engine and the deterioration of the exhaust emission can be effectively suppressed.

  Further, according to the system of the first embodiment, the cleaning solvent is circulated through the cleaning solvent circulation path by driving the fuel pump 18. For this reason, since the number of parts can be reduced compared with the structure which receives the pump for circulating a washing | cleaning solvent separately, manufacturing cost can be held down effectively.

  By the way, according to the first embodiment described above, the cleaning solvent is introduced into the filter 30 and the fuel pump 18 by refluxing the cleaning solvent from the return pipe 36 connected in the middle of the discharge pipe 24. The connection place of the return pipe 36 is not limited to the discharge pipe 24. FIG. 4 is a diagram for explaining a modification of the system according to the first embodiment. As shown in this figure, the return pipe 36 is connected to the downstream side of the fuel return pipe 28. A switching valve 46 is connected to a connection portion between the return pipe 36 and the fuel return pipe 28. According to such a configuration, by switching the switching valves 44 and 46 to the B side, the cleaning solvent tank 32 → the introduction pipe 34 → the suction pipe 22 → the filter 30 → the fuel pump 18 → the discharge pipe 24 → the common rail 20 → the connection pipe. A cleaning solvent circulation path is formed which communicates with 26 → fuel injection valve 14 → return pipe 36 → cleaning solvent tank 32. Therefore, the cleaning solvent can be circulated and cleaned not only in the filter 30 and the fuel pump 18 but also in fuel system parts such as the connection pipe 26 and the fuel injection valve 14. This also applies to other embodiments described below.

  Further, according to the first embodiment described above, the cleaning solvent is circulated through the cleaning solvent circulation path by driving the fuel pump 18, but the pump for circulating the cleaning solvent is not limited to this. . That is, a separate pump may be provided in the return pipe 36 and the cleaning solvent may be circulated by the pump. This also applies to other embodiments described below.

  Further, according to the first embodiment described above, the return pipe 36 is connected to the discharge pipe 24 on the downstream side of the fuel pump 18, and the switching valve 46 is arranged at these connecting portions. The structure for forming is not limited to this. FIG. 5 is a diagram for explaining a modification of the first embodiment. As shown in this figure, the return pipe 36 is connected to the fuel pump 181. The fuel pump 181 is a pump having a function similar to that of the switching valve 46 inside, and freely switches the discharge destination of the solvent introduced from the suction pipe 22 between the discharge pipe 24 and the return pipe 36. Can do. According to such a configuration, by switching the discharge destination of the fuel pump 181 to the return pipe 36, a cleaning solvent circulation path similar to the system in the first embodiment described above can be formed. This also applies to other embodiments described below.

  Further, according to the above-described first embodiment, the timing of executing the cleaning operation of the fuel system parts is determined based on the biofuel concentration X and the accumulated operation time of the fuel pump 18. The determination method is not limited to this. That is, if it can be determined that the polymer has accumulated in the fuel supply path, for example, it is determined whether or not the polymer has accumulated on the filter 30 based on the pressure difference before and after passing through the filter 30. Alternatively, it may be determined that a clogging or the like has occurred in the fuel supply path when an engine start failure occurs. Further, the deposit amount was estimated based on the biofuel concentration X and the operation state (fuel supply amount, integrated amount, engine temperature, etc.) of the diesel engine 10, and the deposit amount became larger than a predetermined amount. In such a case, it may be determined that cleaning is performed. This also applies to other embodiments described below.

  Further, according to the first embodiment described above, when cleaning the fuel system parts, the fuel pump 18 is driven to circulate the cleaning solvent for a predetermined time. However, the cleaning method is limited to this. Absent. In other words, in a state where the cleaning solvent circulation path is filled with the cleaning solvent, the driving of the fuel pump 18 may be stopped once and left for a while. Thereby, consumption of the electric power for driving the fuel pump 18 can be suppressed efficiently. This also applies to other embodiments described below.

  Moreover, in Embodiment 1 mentioned above, it is supposed that the washing operation of fuel system parts is performed while the diesel engine 10 is stopped. For this reason, it is assumed that there is a request for starting the engine during the cleaning of the fuel system parts. Therefore, when there is a request for starting the engine during the cleaning of the fuel system parts, the engine start may be prohibited and a warning or the like may be issued. Thereby, it is possible to effectively avoid a situation where the cleaning solvent is mixed in a large amount in the biofuel. Further, when the vehicle on which the diesel engine 10 is mounted is a hybrid vehicle further provided with another output device such as a motor, the cleaning is performed when there is a request for starting the engine during the cleaning of the fuel system parts. Until the process ends, the output may be substituted by another output device. As a result, the output request can be satisfied even while the fuel system parts are being cleaned. This also applies to other embodiments described below.

  In the first embodiment described above, the positional relationship between the fuel tank 16 and the cleaning solvent tank 32 is not particularly limited. However, the positional relationship in which the cleaning solvent liquid level is always lower than the biofuel liquid level. It is desirable to make it. This effectively prevents the cleaning solvent in the cleaning solvent tank 32 from flowing into the fuel tank 16 through the inlet pipe 34 and the suction pipe 22 due to the negative pressure in the pipe when the switching valve 44 fails. Can be suppressed. This also applies to other embodiments described below.

  Moreover, in Embodiment 1 mentioned above, although it is supposed that the fuel system component is wash | cleaned about the diesel engine 10 which uses biofuel, the internal combustion engine to which this invention is applied is not restricted to this. That is, even if the internal combustion engine uses other fuels, at least the effects of the present invention can be achieved as long as the internal combustion engine is capable of clogging the fuel supply path and cannot burn a large amount of the cleaning solvent. be able to. This also applies to other embodiments described below.

  In the first embodiment described above, the diesel engine 10 is the “internal combustion engine” in the first invention, the biofuel is the “fuel” in the first invention, the suction pipe 22, the discharge pipe 26, and The connecting pipe 26 corresponds to the “fuel pipe” in the first invention, and the cleaning solvent circulation path corresponds to the “circulation path” in the first invention. Further, the ECU 40 executes the processing of step 106, whereby the “circulation path forming means” and the “fuel system cleaning means” in the first invention are realized.

  In the first embodiment described above, the switching valve 44 is the “first switching means” in the second invention, and the switching valve 46 is the “second switching means” in the second invention. It corresponds. Further, the “control means” according to the second aspect of the present invention is implemented when the ECU 40 executes the process of step 106.

  In the first embodiment described above, the “replacement means” according to the tenth aspect of the present invention is implemented when the ECU 40 executes the processing of steps 110 to 114.

  In the first embodiment described above, the “determination means” according to the twelfth aspect of the present invention is implemented by the ECU 40 executing the process of step 104 described above.

Embodiment 2. FIG.
[Configuration of Embodiment 2]
Next, a second embodiment of the present invention will be described with reference to FIG. 6 and FIG. FIG. 6 is a diagram for explaining the configuration of the system according to the embodiment of the present invention. 6 that are the same as those in FIG. 1 are assigned the same reference numerals, and redundant descriptions are omitted or simplified.

  As shown in FIG. 6, in addition to the configuration shown in FIG. 1, the system of the present embodiment has a fuel pump 18, a suction pipe 22, a discharge pipe 24, a filter 30, an introduction pipe 34, a return pipe 36, and a switching valve 44. , 46 (hereinafter collectively referred to as “first fuel system”), the second fuel pump 50, the second suction pipe 52, the second discharge pipe 54, and the second filter, which are configured in the same manner as the first fuel system. 56, a second cleaning solvent pipe 58, a second return pipe 60, and second switching valves 62 and 64 (hereinafter collectively referred to as “second fuel system”).

[Operation of Embodiment 2]
Next, characteristic operations in the system of the present embodiment will be described. In the system of the first embodiment described above, biofuel cannot be injected from the fuel injection valve 14 during the cleaning of the fuel system parts. For this reason, in the system of the first embodiment, when the diesel engine 10 is stopped, the fuel system parts are cleaned.

  On the other hand, the system of the second embodiment is characterized in that the fuel system parts can be cleaned even when the diesel engine 10 is in operation. More specifically, when the fuel system parts are cleaned in the first fuel system, the switching valves 44 and 46 are switched to the B side, and the cleaning solvent tank 32 → the introduction pipe 34 → the suction pipe 22 → the filter 30. A cleaning solvent circulation path communicating with the fuel pump 18 → the discharge pipe 24 → the return pipe 36 → the cleaning solvent tank 32 is formed. At this time, in the second fuel system, the second switching valves 62 and 64 are switched to the A side so that the fuel tank 16 → the second suction pipe 52 → the second filter 56 → the second fuel pump. A second fuel supply path communicating with 50 → second discharge pipe 54 → common rail 20 → connection pipe 26 → fuel injection valve 14 is formed. Therefore, biofuel can be supplied from the second fuel supply path to the fuel injection valve 14 while the fuel system parts are being cleaned in the cleaning solvent circulation path.

  On the other hand, when the cleaning of the fuel system parts in the first fuel system is completed, the cleaning of the fuel system parts in the second fuel system is then executed. More specifically, first, in the second fuel system, the second switching valves 62 and 64 are switched to the B side, and the cleaning solvent tank 32 → the second cleaning solvent pipe 58 → the second suction pipe. 52 → second filter 56 → second fuel pump 50 → second discharge pipe 54 → second return pipe 60 → second cleaning solvent circulation path communicating with the cleaning solvent tank 32 is formed. At this time, in the first fuel system, the switching valves 44 and 46 are switched to the A side, and the fuel tank 16 → the suction pipe 22 → the filter 30 → the fuel pump 18 → the discharge pipe 24 → the common rail 20 → the connection pipe 26. → A fuel supply path communicating with the fuel injection valve 14 is formed. For this reason, the biofuel can be supplied from the fuel supply path to the fuel injection valve 14 while the fuel system parts are being cleaned in the second cleaning solvent circulation path.

  As described above, when one of the first fuel system and the second fuel system is being cleaned, fuel can be supplied using the other fuel system. The fuel system can be efficiently cleaned without stopping.

[Specific Processing in Second Embodiment]
Next, with reference to FIG. 7, the specific content of the process performed in this Embodiment is demonstrated. FIG. 7 is a flowchart of a routine executed by the ECU 40 for cleaning the fuel system. Note that the routine shown in FIG. 7 is executed during the operation of the engine.

  In the routine shown in FIG. 7, first, the bioconcentration X of the biofuel is detected (step 200). Next, a threshold value TLX is set (step 202). Next, it is determined whether or not the operating time T1AX of the fuel pump 18 is greater than the threshold value TLX (step 204). Here, specifically, the same processing as in steps 100 to 104 is executed. As a result, when the establishment of T1AX> TLX is not recognized, it is determined that the oxidative degradation of the biofuel has not progressed, and this routine is immediately terminated.

  On the other hand, when the establishment of T1AX> TLX is recognized in the above step 204, it is determined that the oxidative degradation of the biofuel has progressed and the clogging of the polymer has occurred in the fuel supply path, and the next step Then, the cleaning of the first fuel system and the fuel supply by the second fuel system are started (step 206). Here, specifically, first, the second fuel pump 50 is driven in a state where the second switching valves 62 and 64 are respectively switched to the A side. As a result, the biofuel in the fuel tank 16 passes through the second fuel system and is supplied to the fuel injection valve 14. Next, the switching valves 44 and 46 are respectively switched to the B side. Thereby, the cleaning solvent is circulated in the first fuel system.

  Next, it is determined whether or not a predetermined time has elapsed since the process of step 206 was executed (step 208). Here, specifically, it is determined whether or not a time (for example, 1 minute) for sufficiently cleaning the fuel system parts has elapsed. Then, this step is repeatedly executed until a predetermined time elapses. As a result, if it is determined that the predetermined time has elapsed, it is determined that the first fuel system has been sufficiently cleaned, and the process proceeds to the next step to clean the second fuel system and the first fuel. The fuel supply by the system is started (step 210). Specifically, first, processing similar to the processing in steps 110 to 114 is executed, and the switching valve 46 is switched to the A side after the first fuel system is replaced with biofuel. Thereby, the biofuel in which the cleaning solvent is not mixed is supplied to the fuel injection valve 14. Next, the second switching valves 62 and 64 are respectively switched to the B side. Thereby, the cleaning solvent is circulated in the second fuel system.

  Next, it is determined whether or not a predetermined time has elapsed since the process of step 210 was executed (step 212). Here, specifically, it is determined whether or not a time (for example, 1 minute) for sufficiently cleaning the fuel system parts has elapsed. Then, this step is repeatedly executed until a predetermined time elapses. As a result, when it is determined that the predetermined time has elapsed, it is determined that the first fuel system has been sufficiently cleaned, the process proceeds to the next step, and the cleaning of the second fuel system is completed ( Step 214). Here, specifically, the same processing as the processing of steps 110 to 116 is executed for the second fuel system. Thereby, the second fuel pump 50 is stopped after the second fuel system is replaced with the biofuel.

  As described above, according to the system of the second embodiment, it is possible to supply fuel using the second fuel system while the first fuel system is being cleaned. For this reason, even when the diesel engine 10 is in operation, the fuel system parts can be cleaned.

  By the way, according to the second embodiment described above, the cleaning of the second fuel system is performed after the cleaning of the first fuel system is completed. However, the cleaning timing of the second fuel system is limited to this. I can't. That is, the cleaning timing may be determined by separately determining whether or not the second fuel system needs to be cleaned.

  In the second embodiment described above, the diesel engine 10 is the “internal combustion engine” in the first invention, the biofuel is the “fuel” in the first invention, the suction pipe 22, the discharge pipe 26, and The connecting pipe 26 corresponds to the “fuel pipe” in the first invention, and the cleaning solvent circulation path corresponds to the “circulation path” in the first invention. Further, the ECU 40 executes the process of step 206, whereby the “circulation path forming means” and the “fuel system cleaning means” in the first invention are realized.

  In the second embodiment, the switching valve 44 is the “first switching means” in the second invention, and the switching valve 46 is the “second switching means” in the second invention. It corresponds. Further, the “control means” according to the second aspect of the present invention is implemented when the ECU 40 executes the process of step 206.

  In the above-described second embodiment, the second suction pipe 52, the second discharge pipe 52, and the second connection pipe 54 are the second fuel pipes in the ninth invention. It corresponds to “Piping”. Further, the ECU 40 executes the process of step 206 to realize the “second fuel supply means” in the ninth aspect of the invention.

  In the second embodiment described above, the “determination means” according to the twelfth aspect of the present invention is implemented when the ECU 40 executes the process of step 204.

Embodiment 3 FIG.
[Features of Embodiment 3]
Next, a third embodiment of the present invention will be described with reference to FIG. The system of the present embodiment can be realized by causing the ECU 40 to execute a routine shown in FIG. 8 to be described later using the hardware configuration shown in FIG.

  In the second embodiment described above, the fuel system cleaning timing is determined based on the bioconcentration of the biofuel and the accumulated operation time T1AX of the fuel pump 18. Here, if the vehicle is left without starting the engine for a long period of time, a polymer may accumulate in the fuel pipe and cause a start failure. Therefore, in the third embodiment, when a start failure occurs, fuel is supplied using the second fuel system and the engine is started. As a result, the diesel engine 10 can be started even when the first fuel system is clogged or the like.

[Specific Processing in Embodiment 3]
Next, with reference to FIG. 8, the specific content of the process performed in this Embodiment is demonstrated. FIG. 8 is a flowchart of a routine executed when the ECU 40 turns on the ignition (IG).

  In the routine shown in FIG. 8, it is first determined whether or not an engine start failure has occurred (step 300). Here, it is determined whether or not the engine is started when fuel is supplied in the first fuel system. As a result, when the engine starts without any problem, this routine is immediately terminated. On the other hand, if the engine does not start, it is determined that the first fuel system is clogged with polymer, etc., and then the process proceeds to step to supply fuel in the second fuel system. Is performed (step 302). Here, specifically, the second fuel pump 50 is driven after the second switching valves 62 and 64 are respectively switched to the A side.

  Next, the engine is started (step 304). Next, cleaning of the first fuel system is started (step 306). Specifically, first, the fuel pump 18 is driven in a state where the switching valves 44 and 46 are respectively switched to the A side. Thereby, the cleaning solvent is circulated in the first fuel system.

  Next, it is determined whether or not a predetermined time has elapsed since the process of step 306 was executed (step 308). Next, cleaning of the second fuel system and fuel supply by the first fuel system are started (step 310). Next, it is determined whether or not a predetermined time has elapsed since the process of step 310 was executed (step 312). As a result, when it is determined that the predetermined time has elapsed, the cleaning of the second fuel system is ended (step 314). Here, specifically, the same processing as the processing in steps 208 to 214 is executed.

  As described above, according to the system of the third embodiment, the engine can be started using the second fuel system even when a start failure of the engine occurs. In addition, the first fuel system can be efficiently cleaned while the engine is operated using the second fuel system.

  By the way, according to the third embodiment described above, the second fuel system is cleaned after the cleaning of the first fuel system is finished, but the cleaning timing of the second fuel system is limited to this. I can't. That is, the cleaning timing may be determined by separately determining whether or not the second fuel system needs to be cleaned.

  In the third embodiment described above, the diesel engine 10 is the “internal combustion engine” in the first invention, the biofuel is the “fuel” in the first invention, the suction pipe 22, the discharge pipe 26, and The connecting pipe 26 corresponds to the “fuel pipe” in the first invention, and the cleaning solvent circulation path corresponds to the “circulation path” in the first invention. Further, when the ECU 40 executes the process of step 306, the “circulation path forming means” and the “fuel system cleaning means” in the first aspect of the present invention are realized.

  In the third embodiment described above, the switching valve 44 is the “first switching means” in the second invention, and the switching valve 46 is the “second switching means” in the second invention. It corresponds. Further, the “control means” in the second aspect of the present invention is realized by the ECU 40 executing the processing of step 306.

  In the third embodiment described above, the second suction pipe 52, the second discharge pipe 52, and the second connection pipe 54 are the second fuel pipes in the ninth invention. It corresponds to “Piping”. Further, the ECU 40 executes the processing of step 302 described above, thereby realizing the “second fuel supply unit” in the ninth aspect of the invention.

  In the third embodiment described above, the “second determination means” according to the thirteenth aspect of the present invention is implemented when the ECU 40 executes the process of step 300.

Embodiment 4 FIG.
[Features of Embodiment 4]
Next, a third embodiment of the present invention will be described with reference to FIG. The system of the present embodiment can be realized by causing the ECU 40 to execute a routine shown in FIG. 9 to be described later using the hardware configuration shown in FIG.

  When the fuel system parts are repeatedly cleaned, the concentration of the dissolved polymer in the cleaning solvent tank 32 increases. Therefore, in the fourth embodiment, whether or not the cleaning solvent needs to be replaced is determined based on the accumulated time during which the cleaning solvent is circulated.

[Specific Processing in Embodiment 4]
Next, with reference to FIG. 9, the specific content of the process performed in this Embodiment is demonstrated. FIG. 9 is a flowchart of a routine executed by the ECU 40 to determine whether or not the cleaning solvent needs to be replaced.

  In the routine shown in FIG. 9, first, an accumulated time ΣT1B in which the fuel system parts are cleaned is acquired (step 400). Here, specifically, the integrated value of the operating time of the fuel pump 18 under the condition that the switching valve 44 is set to the B side is acquired.

  Next, it is determined whether or not the integration time ΣT1B is longer than the threshold value TCL (step 402). As the threshold value TCL, a value defined in advance through experiments or the like is used as the time required for replacing the cleaning solvent in the cleaning solvent tank 32. As a result, if it is not recognized that the cumulative time ΣT1B> threshold value TCL is established, it is determined that the cleaning solvent in the cleaning solvent tank 32 can be used, and this routine is immediately terminated.

  On the other hand, if it is determined in step 402 that the cumulative time ΣT1B> threshold value TCL is established, it is determined that the cleaning solvent in the cleaning solvent tank 32 is unusable, and the process proceeds to the next step. It is determined that the solvent needs to be replaced (step 404). Here, specifically, a warning or the like is issued to notify the driver that the cleaning solvent needs to be replaced.

  Next, it is determined whether or not the cleaning solvent has been replaced (step 406). As a result, if the cleaning solvent has not been exchanged yet, the routine proceeds to step 404 again, and a warning or the like is issued.

  On the other hand, if it is determined in step 406 that the cleaning solvent has been replaced, the process proceeds to the next step, where the integrated time ΣT1B is reset and the warning is stopped (step 408).

  As described above, according to the system of the fourth embodiment, since it is possible to determine whether or not the cleaning solvent needs to be replaced, it is possible to effectively suppress a situation in which a cleaning solvent having a high weight concentration is used. it can.

  By the way, according to the above-described fourth embodiment, whether or not the cleaning solvent needs to be replaced is determined based on the accumulated time ΣT1B. However, the determination of whether or not replacement is necessary is not limited to this. That is, the deterioration state may be detected from the viscosity or color of the cleaning solvent to determine whether the cleaning solvent needs to be replaced.

  Further, according to the fourth embodiment described above, the present invention is implemented in the system shown in FIG. 1, but includes the system shown in FIG. 6, that is, the first fuel system and the second fuel system. The present invention may be implemented in the system.

  In the fourth embodiment described above, the “third determination means” according to the seventeenth aspect of the present invention is realized by the ECU 40 executing the process of step 402.

Embodiment 5 FIG.
[Features of Embodiment 5]
Next, Embodiment 3 of the present invention will be described with reference to FIG. The system of the present embodiment can be realized by causing the ECU 40 to execute a routine shown in FIG. 10 to be described later using the hardware configuration shown in FIG.

  In the first embodiment described above, when the cleaning of the fuel system parts is finished, the fuel supply path is switched to the fuel supply path after being replaced with biofuel. For this reason, not a little biofuel flows into the cleaning solvent tank 32. For this reason, when the cleaning of the fuel system parts is repeatedly executed, the amount of the cleaning solvent gradually increases. Therefore, in the fourth embodiment, when the amount of the washing solvent becomes larger than a predetermined reference value, the biofuel is used in a range (for example, 1%) that does not affect the combustion of the engine during operation of the diesel engine 10. A washing solvent will be added. Thereby, the liquid level of the cleaning solvent tank 32 can be maintained appropriately, and the situation where the cleaning solvent overflows and the situation where an abnormality occurs in the tank internal pressure can be effectively suppressed.

[Specific Processing in Embodiment 5]
Next, with reference to FIG. 10, the specific content of the process performed in this Embodiment is demonstrated. FIG. 10 is a flowchart of a routine that the ECU 40 executes while the diesel engine 10 is in operation.

  In the routine shown in FIG. 10, first, the cleaning solvent amount V1 in the cleaning solvent tank 32 is acquired (step 500). Here, specifically, it is acquired based on the output signal of the level sensor 48 provided in the cleaning solvent tank 32.

  Next, it is determined whether or not the cleaning solvent amount V1 is larger than a predetermined reference value Vmax (step 502). As the reference value Vmax, a preset value is used as the maximum allowable amount of the cleaning solvent. As a result, if the establishment of the cleaning solvent amount V1> the reference value Vmax is not recognized, it is determined that there is no problem due to the increase in the cleaning solvent amount, and this routine is immediately terminated.

  On the other hand, if it is determined in step 502 that the cleaning solvent amount V1> the reference value Vmax is established, it is determined that a problem due to the increase in the cleaning solvent occurs, the process proceeds to the next step, and the fuel injection valve A cleaning solvent is added to the biofuel supplied to 14 (step 504). Here, specifically, the switching solvent 44 is intermittently switched to the B side, so that the cleaning solvent is added to the biofuel in the suction pipe 22. The addition amount is set to an amount that does not affect the combustion state of the diesel engine 10 (for example, about 1%).

  As described above, according to the system of the fifth embodiment, since the increased amount of the cleaning solvent can be burned by the diesel engine 10, the liquid level of the cleaning solvent tank 32 is maintained appropriately, and the cleaning solvent overflows. It is possible to effectively suppress the situation and the situation where an abnormality occurs in the tank internal pressure.

  By the way, according to the fifth embodiment described above, the cleaning solvent amount V1 is acquired based on the output signal of the level sensor provided in the cleaning solvent tank 32. However, the method of acquiring the cleaning solvent amount V1 is as follows. It is not limited to this. That is, it is good also as estimating based on the washing | cleaning log | history of fuel system components, and good also as acquiring the washing | cleaning solvent amount V1 using another well-known method.

  Further, according to the fifth embodiment described above, the cleaning solvent is added to the biofuel in the suction pipe 22 by switching the switching valve 44 to the B side intermittently. It is not limited to this. That is, a metering valve may be provided at the connection portion between the battlefield culture pipe 34 and the suction pipe 22 to control the opening of the metering valve.

  Further, according to the fifth embodiment described above, the present invention is executed in the system shown in FIG. 1, but includes the system shown in FIG. 6, that is, the first fuel system and the second fuel system. The present invention may be implemented in the system.

  In the fifth embodiment described above, the “cleaning solvent supply means” according to the eighteenth aspect of the present invention is realized by the ECU 40 executing the process of step 504.

Embodiment 6 FIG.
[Features of Embodiment 6]
Next, a sixth embodiment of the present invention will be described with reference to FIG. The system of the present embodiment can be realized by causing the ECU 40 to execute a routine shown in FIG. 11, which will be described later, using the hardware configuration shown in FIG.

  In the first embodiment described above, the fuel system parts are cleaned when a clogged polymer or the like occurs in the fuel supply path. However, when the remaining amount of the cleaning solvent is insufficient, it may be assumed that a desired cleaning effect cannot be obtained. Therefore, in the sixth embodiment, the cleaning operation is prohibited in a condition where a desired cleaning effect cannot be obtained. More specifically, first, when the liquid level L of the cleaning solvent suddenly increases, biofuel in the fuel tank 16 may flow into the cleaning solvent tank 32. In addition, when the liquid level L of the cleaning solvent rapidly decreases, there is a possibility that the cleaning solvent in the cleaning solvent tank 32 flows into the fuel tank 16. Therefore, when the amount of time change dL / dt of the liquid level exceeds a predetermined reference value range, the cleaning operation is prohibited and attention is urged by a warning lamp.

  Furthermore, the cleaning effect of the cleaning solvent is significantly reduced at extremely low temperatures. On the other hand, when the temperature is extremely high, the reflux performance decreases due to the generation of vapor. Therefore, when the temperature T of the cleaning solvent is out of the predetermined reference temperature range, the cleaning operation is prohibited and attention is urged by a warning lamp. Thereby, it is possible to effectively avoid a situation where a cleaning operation without a cleaning effect is executed.

[Specific Processing in Embodiment 6]
Next, with reference to FIG. 11, the specific content of the process performed in this Embodiment is demonstrated. FIG. 11 is a flowchart of a routine that the ECU 40 executes.

  In the routine shown in FIG. 11, first, the liquid level L of the cleaning solvent in the cleaning solvent tank 32 is acquired (step 600). Here, specifically, the liquid level L is acquired based on the output signal of the level sensor 48. Next, a time change amount dL / dt of the liquid level L is calculated (step 602). Next, it is determined whether or not the temporal change amount dL / dt of the liquid level L is larger than a predetermined reference value Cmax (step 604). The reference value Cmax is a maximum allowable value for determining that the time change amount dL / dt is normal, and a value set in advance through experiments or the like is used. As a result, when it is recognized that the time variation dL / dt> the reference value Cmax is established, it is determined that the biofuel in the fuel tank 16 flows into the cleaning solvent tank 32, and the next step is performed. Then, the cleaning operation of the fuel system parts is prohibited (step 606). Here, specifically, switching of the switching valves 44 and 46 is prohibited and a warning is issued to the driver.

  On the other hand, if the time variation dL / dt> the reference value Cmax is not established in step 604, it is determined that there is no possibility that the biofuel in the fuel tank 16 is flowing into the cleaning solvent tank 32. Then, the process proceeds to the next step, and it is determined whether or not the temporal change amount dL / dt of the liquid level L is smaller than a predetermined reference value Cmin (step 608). The reference value Cmin is a minimum allowable value for determining that the time change amount dL / dt is normal, and a value set in advance through an experiment or the like is used. As a result, when it is recognized that the time variation dL / dt <the reference value Cmin is established, it is determined that the cleaning solvent in the cleaning solvent tank 32 flows into the fuel tank 16, and the process proceeds to step 606. The cleaning operation of the fuel system parts is prohibited.

  On the other hand, if it is not determined in step 608 that the time variation dL / dt <the reference value Cmin is established, it is determined that there is no possibility that the cleaning solvent in the cleaning solvent tank 32 flows into the fuel tank 16. Then, the process proceeds to the next step, and the temperature T of the cleaning solvent is acquired (step 610).

  Next, it is determined whether or not the temperature T of the cleaning solvent is within a predetermined reference range (step 612). Here, specifically, it is determined that Tmin <T <Tmax is satisfied. Tmin and Tmax are the minimum and maximum temperatures at which a desired cleaning effect can be exhibited, and values set in advance through experiments or the like are used. As a result, if the establishment of Tmin <T <Tmax is not recognized, it is determined that the desired cleaning effect cannot be exhibited, and the routine proceeds to step 606, where the cleaning operation of the fuel system parts is prohibited. .

  As described above, according to the system of the sixth embodiment, it is determined whether or not a desired cleaning effect can be exhibited. When the cleaning effect cannot be exhibited, the cleaning operation can be prohibited. For this reason, the situation where the washing operation without a washing effect is performed can be avoided effectively.

  By the way, according to the above-described sixth embodiment, the present invention is executed in the system shown in FIG. 1, but includes the system shown in FIG. 6, that is, the first fuel system and the second fuel system. The present invention may be implemented in the system.

  In the fifth embodiment described above, the ECU 40 executes the processing of steps 612 and 606, whereby the “third prohibiting means” in the fifteenth aspect of the invention is the steps 604, 608, and 606. By executing the process, the “fourth prohibition means” in the sixteenth aspect of the present invention is realized.

It is a figure for demonstrating the structure of the system which concerns on Embodiment 1 of this invention. It is a flowchart of the routine performed in Embodiment 1 of the present invention. The map which prescribed | regulated the relationship between the bioconcentration X and threshold value TLX is shown. It is a figure for demonstrating the modification of the system which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the modification of the system which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the structure of the system which concerns on Embodiment 2 of this invention. It is a flowchart of the routine performed in Embodiment 2 of this invention. It is a flowchart of the routine performed in Embodiment 3 of the present invention. It is a flowchart of the routine performed in Embodiment 4 of this invention. It is a flowchart of the routine performed in Embodiment 5 of this invention. It is a flowchart of the routine performed in Embodiment 6 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Diesel engine 12 Cylinder 14 Fuel injection valve 16 Fuel tank 18,181 Fuel pump 20 Common rail 22 Suction piping 24 Discharge piping 26 Connection piping 28 Fuel return piping 30 Filter 32 Cleaning solvent tank 34 Introducing piping 36 Return piping 40 ECU (Electronic Control Unit) )
42 Bio-concentration sensors 44, 46 Switching valve 48 Level sensor 50 Second fuel pump 52 Second suction pipe 54 Second discharge pipe 56 Second filter 58 Second cleaning solvent pipe 60 Second return pipe 62 , 64 Second switching valve

Claims (19)

A fuel tank for storing fuel used for combustion of the internal combustion engine;
A fuel pipe for supplying fuel in the fuel tank to the internal combustion engine;
A cleaning solvent tank for storing the cleaning solvent;
An introduction pipe for selectively communicating one end of a section to be cleaned of the fuel pipe and the cleaning solvent tank;
A return pipe for selectively communicating the other end of the cleaning target section and the cleaning solvent tank;
Circulation that forms a circulation path for circulating the cleaning solvent in the cleaning solvent tank by switching the communication destination of the section to be cleaned to the introduction pipe and the return pipe when cleaning the fuel system of the internal combustion engine A route forming means;
A fuel system cleaning means for cleaning the fuel system by circulating a cleaning solvent in the circulation path;
A fuel system cleaning device for an internal combustion engine. The circulation path forming means includes
First switching means for switching a communication destination at one end of the cleaning target section between the introduction pipe side and the fuel pipe side;
Second switching means for switching the communication destination at the other end of the section to be cleaned between the return pipe side and the fuel pipe side;
When cleaning the fuel system, the first switching means switches the communication destination at one end of the cleaning target section to the introduction pipe side, and the second switching means sets the communication destination at the other end of the cleaning target section. Control means for switching to the return pipe side;
The fuel system cleaning apparatus for an internal combustion engine according to claim 1, comprising:   3. The fuel system cleaning apparatus for an internal combustion engine according to claim 1, wherein fuel system parts are arranged in the section to be cleaned. The fuel system component includes a fuel pump for pumping the fuel in the fuel tank to the fuel injection valve,
4. The fuel system cleaning apparatus for an internal combustion engine according to claim 3, wherein the fuel system cleaning means circulates a cleaning solvent in the circulation path using a driving force of the fuel pump. The fuel pipe includes a fuel return pipe for returning the fuel not injected by the fuel injection valve to the fuel tank,
The fuel system cleaning apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein the other end of the section to be cleaned is provided in the middle of the fuel return pipe.   The internal combustion engine according to any one of claims 1 to 5, wherein the cleaning solvent tank is disposed at a position where the liquid level of the cleaning solvent tank is always lower than the liquid level of the fuel tank. Fuel system cleaning device.   The internal combustion engine according to any one of claims 1 to 6, wherein the fuel system cleaning means stops the circulation of the cleaning solvent and then leaves the cleaning solvent for a predetermined period after introducing the cleaning solvent into the circulation path. Engine fuel system cleaning device.   8. The fuel system cleaning apparatus for an internal combustion engine according to claim 1, further comprising prohibiting means for prohibiting starting of the internal combustion engine during execution of the fuel system cleaning means. A second fuel pipe for supplying fuel in the fuel tank to the internal combustion engine;
Second fuel supply means for supplying the fuel in the fuel tank to the internal combustion engine via the second fuel pipe during execution of the fuel system cleaning means;
The fuel system cleaning apparatus for an internal combustion engine according to claim 1, further comprising:   2. The apparatus according to claim 1, further comprising a replacement unit that replaces the cleaning solvent flowing in the cleaning target section with the fuel in the fuel tank when a request to stop the fuel system cleaning unit is issued. The fuel system cleaning apparatus for an internal combustion engine according to any one of claims 1 to 9.   The replacement means switches the communication destination at the other end of the cleaning target section from the return pipe side after a predetermined time has elapsed after switching the communication destination at one end of the cleaning target section from the introduction pipe side to the fuel pipe side. 11. The fuel system cleaning apparatus for an internal combustion engine according to claim 10, wherein the fuel system is switched to the fuel pipe side. The fuel supplied to the internal combustion engine is biofuel,
Means for estimating the amount of deposits attached to the fuel system based on the concentration of biofuel and the operating state of the internal combustion engine;
Determination means for determining whether or not the fuel system needs to be cleaned based on the amount of deposit;
The fuel system cleaning device for an internal combustion engine according to any one of claims 1 to 11, further comprising:   The internal combustion engine according to any one of claims 1 to 12, further comprising a second determination unit that determines that the fuel system needs to be cleaned when a start failure of the internal combustion engine occurs. Fuel system cleaning device.   14. The apparatus according to claim 1, further comprising second prohibiting means for prohibiting execution of the fuel system cleaning means when the amount of the cleaning solvent in the cleaning solvent tank is smaller than a predetermined reference value. A fuel system cleaning device for an internal combustion engine according to any one of the preceding claims.   15. The apparatus according to claim 1, further comprising a third prohibiting unit that prohibits execution of the fuel system cleaning unit when a cleaning solvent temperature exceeds a predetermined reference range. A fuel system cleaning device for an internal combustion engine.   4. The apparatus according to claim 1, further comprising: a fourth prohibiting unit that prohibits execution of the fuel system cleaning unit when the amount of time change of the cleaning solvent amount in the cleaning solvent tank exceeds a predetermined reference range. 16. A fuel system cleaning device for an internal combustion engine according to any one of 1 to 15.   17. The third determination unit according to claim 1, further comprising a third determination unit that determines that the cleaning solvent needs to be replaced when an integrated value of execution times of the fuel system cleaning unit is larger than a predetermined reference value. A fuel system cleaning apparatus for an internal combustion engine according to any one of the preceding claims.   When the amount of the cleaning solvent in the cleaning solvent tank exceeds a predetermined reference amount, a cleaning solvent supply means is further provided for supplying the cleaning solvent to the internal combustion engine within a range that does not affect the combustion state of the internal combustion engine. The fuel system cleaning device for an internal combustion engine according to any one of claims 1 to 17, wherein the fuel system cleaning device is an internal combustion engine. In a hybrid vehicle comprising the internal combustion engine and another output device,
An alternative means for driving the other output device in place of the internal combustion engine when an output request to the hybrid vehicle is issued during execution of the fuel system cleaning means. 19. A fuel system cleaning apparatus for an internal combustion engine according to any one of 1 to 18.

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