JP2007016662A - Device for adding cleaning agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for adding a cleaning agent inhibiting deterioration of fuel injection performance due to accumulation of deposits and inhibiting harmful effect of an excessive cleaning agent, in a device mixing a cleaning agent in fuel and supplying the same to a fuel injection valve. <P>SOLUTION: In the device for adding cleaning agent including a combustion chamber and a fuel injection valve 2 injecting and supplying fuel to the combustion chamber in a cylinder, used for an internal combustion engine igniting fuel or combustible mixture of fuel and air, mixing cleaning agent for cleaning deposit accumulated on a injection hole part 21 of the fuel injection valve 2 with fuel, and supplying fuel to which cleaning agent is added to the fuel injection valve 2, a reservoir 71 storing cleaning agent provided separately from a fuel tank 6 storing fuel, and a supply device 70 connecting a cleaning agent supply passage 79 from the reservoir 71 to a fuel supply flow passage 5 from the fuel tank 6 to the fuel injection valve and supplying cleaning agent according to estimated quantity Wd of deposit accumulating on the injection hole part 21. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cleaning agent addition apparatus, which is used in, for example, an internal combustion engine in which fuel is directly injected and supplied into a cylinder, and is preferably applied to a cleaning agent addition apparatus that mixes a cleaning agent with fuel and supplies the fuel to a fuel injection valve. It is a thing.

  Conventionally, as an internal combustion engine, for example, a fuel injection valve is arranged so as to face a combustion chamber in a cylinder, and fuel is directly injected and supplied from the fuel injection valve to the combustion chamber. As this type of fuel injection valve, one having an injection hole portion such as an injection hole for injecting fuel and a valve portion for stopping and supplying fuel injection is known (see Patent Document 1).

  The unburned fuel remaining in the nozzle hole or the like may cause a chemical reaction other than combustion, or may cause deposits (carbon-based compounds) due to precipitation of impurities in the fuel. If the deposit adheres to the inside of the nozzle hole part or its peripheral part, the fuel injection amount may decrease or fluctuate. As a result, it becomes difficult to maintain the initial injection characteristics, and the mixing ratio between the injected fuel and air that affects the performance of the internal combustion engine changes. Therefore, it is important to prevent deposit generation and adhesion. In particular, in a so-called direct injection fuel injection device that directly injects fuel into the combustion chamber, the inside or the periphery of the injection hole is exposed by the combustion gas containing flame and unburned fuel, so the influence is remarkable.

Patent Document 1 discloses a technique of forming a liquid repellent film including a fluoroalkyl group around the nozzle hole and suppressing deposit adhesion. As a method of forming the liquid repellent film on the surface of the nozzle hole, for example, the liquid repellent film is baked by a sol-gel method so that the surface has liquid repellency.
JP 10-159688 A

  However, in the conventional technology such as Patent Document 1, even if the nozzle hole is formed with a liquid repellent film, it is repeatedly exposed to a relatively high-temperature flame or the like, thereby suppressing deposit adhesion due to thermal deterioration. May fade.

  In contrast, a cleaning agent for purifying deposits such as polyisobuteneamine compounds (hereinafter referred to as PIBA) is added to the fuel in a mixed manner, and the deposits adhering to the nozzle holes are cleaned when the fuel injection valve is injected. A method of washing off with an additive-added fuel is conceivable. When such a device is applied to the conventional direct injection fuel injection device, the injected fuel may adhere to the piston head or the cylinder wall forming the combustion chamber, which easily causes the generation of the combustion chamber deposit. Therefore, it is necessary to limit the amount of detergent added.

  The present invention has been made in consideration of such circumstances, and its purpose is to suppress deterioration of fuel injection performance due to deposit adhesion in a case where a detergent is mixed in fuel and supplied to a fuel injection valve. In addition, an object of the present invention is to provide a detergent addition device that can suppress the adverse effects caused by excessive administration of the detergent.

  In order to achieve the above object, the present invention comprises the following technical means.

That is, according to the first to eighth aspects of the present invention, the combustion chamber in the cylinder and the fuel injection valve that injects and supplies fuel to the combustion chamber are ignited by ignition to a combustible mixture or fuel in which air and fuel are mixed. Used in internal combustion engines,
In a cleaning agent addition apparatus that mixes a fuel with a cleaning agent for purifying deposits adhering to the nozzle hole portion of the fuel injection valve, and supplies the fuel with the cleaning agent added thereto to the fuel injection valve.
A cleaning agent supply flow path from the reservoir is connected to a storage tank that is provided separately from the fuel tank that stores the fuel, and a fuel supply flow path that extends from the fuel tank to the fuel injection valve. And a supply device for supplying a cleaning agent in accordance with an estimated amount of deposit adhering to the substrate.

  According to this, a reservoir for storing the cleaning agent is provided separately from the fuel tank for storing the fuel, and the supply device supplies the cleaning agent from the reservoir to the fuel supply flow path from the fuel tank to the fuel injection valve. Since the flow path is connected and the cleaning agent is supplied according to the estimated amount of deposit adhering to the nozzle hole portion, the deterioration of the fuel injection performance due to deposit adhesion is suppressed, and the adverse effect due to excessive administration of the cleaning agent is suppressed. be able to.

In the invention according to claim 2, the fuel supplied to the fuel supply channel is a fuel that sucks up the fuel stored in the fuel tank between the fuel tank and the fuel injection valve and discharges the fuel toward the fuel injection valve. A pump is provided,
The supply device has a solenoid valve for connecting the detergent supply flow path from the reservoir to the fuel suction portion side of the fuel pump and blocking and circulating the flow of the detergent from the reservoir to the fuel pump. Features.

  As a result, the supply device connects the cleaning agent supply flow path from the reservoir to the fuel suction portion side of the fuel pump provided on the fuel supply flow path side, and allows the flow of the cleaning agent from the storage to the fuel pump. Since the electromagnetic valve that shuts off and flows is provided, the amount of the detergent added can be controlled by controlling the opening and closing of the electromagnetic valve.

In the invention according to claim 3, the fuel supplied to the fuel supply flow path is a fuel that sucks up the fuel stored in the fuel tank between the fuel tank and the fuel injection valve and discharges the fuel toward the fuel injection valve. A pump is provided,
The supply device has a pressure feed pump that connects the detergent supply flow path from the reservoir to the fuel discharge part side of the fuel pump and pumps the detergent guided from the reservoir toward the fuel discharge part side of the fuel pump. It is characterized by.

  As a result, the supply device connects the cleaning agent supply flow path from the reservoir to the fuel discharge section side of the fuel pump provided on the fuel supply flow path side, and supplies the cleaning agent guided from the storage to the fuel of the fuel pump. Since there is a pumping pump that pumps toward the discharge part side, the amount and timing of addition of the detergent can be controlled by driving and controlling the pumping pump.

  According to a fourth aspect of the present invention, the supply device includes a control unit that controls the detergent addition timing and the addition amount based on the estimated deposit amount, and the control unit determines the estimated deposit amount as an operating state of the internal combustion engine. It is characterized by determining based on.

  As a result, the detergent mixed and added to the fuel can be stored in a reservoir dedicated to the detergent separately from the fuel tank, and the amount of the detergent supplied to the fuel injection valve can be reduced by the internal combustion engine. It can be made variable according to the driving state.

  According to a fifth aspect of the present invention, the control means includes a dividing means for dividing the operation state of the internal combustion engine into an operation region according to a deposit generation amount index value, and a deposit generation amount index in the divided operation region. Weight coefficient setting means for setting a weight coefficient corresponding to the value and storage means for storing the history of the operation region detected in the operation state of the internal combustion engine are provided.

  Thus, the estimated deposit amount is obtained by accumulating the operation history by setting the weight coefficient of deposit adhesion for each operation region divided into a map of the deposit generation amount, for example, according to the operation state. Therefore, even if the amount of deposit is such that the deposit adhesion does not affect the fuel injection performance, it can be detected in advance.

  In the invention according to claim 6, the control means detects the actual internal combustion engine state index value detected in the operating state of the internal combustion engine affected by deposit adhesion, and the target internal combustion engine state in the operating state of the internal combustion engine. A deposit estimation amount is determined based on the index value.

  As a result, the internal combustion engine state index value is set to, for example, an air-fuel ratio that is a mixture ratio of injected fuel and air, and the target air-fuel ratio that is calculated from the actual air-fuel ratio that is affected by deposit adhesion and the operating state of the internal combustion engine. The estimated deposit amount can be determined by comparing with the estimated deposit amount based on the fuel ratio.

  Further, in the invention according to claim 7, the control means is based on the detected index value of the operating state of the internal combustion engine and the permission index value that is compared with this index value so that the detergent does not deposit in the combustion chamber. And a cleaning agent addition timing determining means for determining the cleaning agent addition timing.

  As a result, the index value of the operating state of the internal combustion engine is detected, for example, the inner wall temperature of the combustion chamber, and is cleaned based on the detected inner wall temperature of the combustion chamber and the permitted inner wall temperature at which the cleaning agent does not deposit in the combustion chamber. Since the agent addition timing is determined, the cleaner can be added when the cleaner is in an operating state of the internal combustion engine that is not deposited in the combustion chamber. Therefore, deterioration of fuel injection performance due to deposit adhesion can be suppressed, and adverse effects due to the administration of the detergent can be prevented.

  In the invention according to claim 8, the control means includes an operating condition changing means for changing the operating condition of the internal combustion engine so that the index value of the operating state of the internal combustion engine satisfies the permission index value. It is characterized by.

  Thereby, the addition amount of the detergent according to the detected deposit estimated amount can be promptly supplied to the fuel injection valve at an appropriate amount in a timely manner. Therefore, deterioration of the fuel injection performance due to deposit adhesion can be prevented.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments in which the detergent adding device of the present invention is applied to a detergent adding device for an internal combustion engine will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram showing the configuration of the detergent addition device of the present embodiment.

  As shown in FIG. 1, a cleaning agent addition device (hereinafter referred to as a cleaning agent addition device) for an internal combustion engine includes an internal combustion engine (not shown), a fuel injection device 1, a cleaning agent supply device 70, and control means. It includes a control device (hereinafter referred to as ECU).

  The fuel injection device 1 is used in an internal combustion engine, particularly a gasoline engine, and injects fuel into each cylinder of, for example, a multi-cylinder (for example, four cylinders) gasoline engine (hereinafter referred to as an engine). The engine is a well-known internal combustion engine provided with a combustion chamber (not shown) in each cylinder. The volume of the combustion chamber increases and decreases as the piston (not shown) reciprocates. The combustion chamber in the cylinder is connected to an intake pipe (not shown) via an intake valve (not shown), and intake air is guided. The combustion chamber is connected to an exhaust pipe (not shown) via an exhaust valve (not shown), and exhausts the exhaust. Further, an ignition device (not shown) is provided to ignite the fuel directly injected into the combustion chamber by the fuel injection valve 2 or a combustible mixture in which air and fuel are mixed. In FIG. 1, only the fuel injection valve 2 corresponding to one of the four cylinders is shown in the drawing, and the other fuel injection valves are not shown.

  The fuel injection device 1 includes a fuel injection valve 2 that injects fuel, a fuel distribution pipe 8 that distributes fuel to the fuel injection valve 2, a fuel pump 7 that pumps fuel toward the fuel distribution pipe 8, a fuel And a fuel tank 6 for storing the fuel sucked up by the pump 7.

  The fuel injection valve 2 is mounted on the engine 100 facing the combustion chamber in the cylinder. The mounting position of the fuel injection valve 2 in the cylinder may be obliquely mounted toward the combustion chamber, or may be centrally mounted substantially at the upper center facing the combustion chamber.

  The fuel injection valve 2 is supplied with fuel pressurized by the fuel pump 7 via a fuel distribution pipe 8. As shown in FIG. 1, the fuel supply pipe 5 constitutes a fuel supply flow path from the fuel tank 6 to the fuel injection valve 2, and the fuel tank 6, the fuel pump 7, and the fuel flow downstream of the fuel flow. The distribution pipe 8 and the fuel injection valve 2 are arranged in this order.

  The fuel injection valve 2 has a substantially cylindrical shape as shown in FIG. 1, receives fuel from one end, and injects fuel from the other end. As shown in FIG. 1, the fuel injection valve 2 includes a valve portion 2b for blocking and allowing fuel injection and an electromagnetic drive portion 2S for driving the valve portion 2b. It is.

  The valve portion 2b is a well-known valve portion having a nozzle needle (not shown) and a valve body (not shown) that accommodates the nozzle needle in an axially movable manner. The valve part 2b has the injection hole 21 which injects a fuel and atomizes. Specifically, a nozzle hole 21 penetrating inward and outward is provided in the valve body. The nozzle holes 21 are not limited to those formed in the valve body, but may be arranged on the tip side of the valve body and formed in a substantially thin plate-like nozzle hole plate. Here, the valve needle 2b opens and closes when the nozzle needle is separated and seated on the valve body. When the valve portion 2b is opened and closed, the valve portion 2b, that is, the fuel injection valve 2, blocks and allows the flow of fuel (fuel injection) supplied to the inside. Further, the valve portion 2b and the injection hole 21 constitute a tip portion for injecting fuel of the fuel injection valve 2. Here, the injection hole 21 constitutes the injection hole part described in the claims.

  The size of the nozzle hole 21, the direction of the nozzle hole axis, the nozzle hole arrangement, and the like are determined according to the required fuel spray shape, direction, number, and the like. The opening area of the nozzle hole defines the flow rate when the valve is opened. The fuel injection amount of the fuel injection valve 2 is measured by the opening area of the opened nozzle hole, the lift amount of the nozzle needle (hereinafter referred to as the needle lift amount), and the valve opening period. When the nozzle needle is seated on the valve body and the valve portion 2b is closed, fuel injection from the injection hole 21 is blocked. On the other hand, when the nozzle needle is separated from the valve body and the valve portion 2b is opened, fuel injection from the injection hole 21 is allowed and fuel is injected. The nozzle hole 21 constitutes a fuel spray forming means for atomizing the fuel and forming a spray.

  As shown in FIG. 1, the electromagnetic drive unit 2S includes a movable core (not shown) that cooperates with the nozzle needle, a fixed core (not shown) that movably accommodates the movable core, and a movable core and a fixed core. This is an electromagnetic drive unit having a well-known structure having a coil (not shown) that acts on the core to act on electromagnetic force. The electromagnetic drive unit 2S includes a lift adjustment mechanism for regulating the maximum movement amount of the needle lift, such as adjusting an axial gap (hereinafter referred to as an air gap) between the movable core and the fixed core. Yes. The nozzle needle is biased in the valve closing direction by a biasing member such as a spring that biases the movable core toward the nozzle hole 21, and the nozzle needle, that is, the fuel injection valve 2 is biased when the coil is not energized. The valve is closed by the biasing force of the member. The fuel injection valve 2 is provided with an urging force adjusting mechanism (not shown) that adjusts the urging force of the urging member. When the coil is energized, an electromagnetic force is generated in the coil, and the movable core and the fixed core are movable. Since an electromagnetic attractive force acts between the core and the core, the movable core is attracted to the side where the needle lift amount increases against the biasing force of the biasing member, and the nozzle needle, that is, the fuel injection valve 2 opens. .

  The cleaning agent supply device 70 includes a reservoir 71 that stores the cleaning agent and an electromagnetic valve 72. As shown in FIG. 1, the detergent supply pipe 79 constitutes a detergent supply flow path connected to the fuel supply pipe 5 side from the reservoir 71, and the reservoir 71, The solenoid valves 72 are arranged in this order. Specifically, in the cleaning agent supply pipe 79, the outlet portion on the downstream side of the cleaning agent flow is connected to the fuel suction portion side of the fuel pump 7. On the other hand, the upstream side of the flow of the detergent is connected to the outside of the fuel tank 6, and a cap 79a as a lid is attached. By opening and closing the cap 79a, the cleaning agent can be replenished.

  The reservoir 71 is a container capable of storing a predetermined amount (for example, 200 cc in this embodiment) of the cleaning agent.

  The electromagnetic valve 72 has a well-known structure that blocks and distributes the flow of the detergent from the reservoir 71 to the fuel pump 7.

  The cleaning agent is a deposit adhesion preventing material that purifies deposits adhering to the injection hole 21 of the fuel injection valve. In this embodiment, a polyisobuteneamine compound (hereinafter referred to as PIBA) is used as a cleaning agent, and is stored in the reservoir 71 in a liquid state. The cleaning agent to be used is not limited to PIBA, and any deposit adhesion prevention agent can be used as long as it can purify deposits adhering to the nozzle hole 21 such as a polyetheramine compound (hereinafter referred to as PEA) or a hydroxylamine compound. It may be a material.

  The ECU 90 is configured as a microcomputer having a known configuration in which a read only memory (ROM), a random access memory (RAM), a microprocessor (CPU), an input port, and an output port are connected to each other via a bidirectional bus. Yes. The ECU 90 controls the energization period of the fuel injection valve 2 by starting and stopping energization of the coil of the fuel injection valve 2 using a power source such as a battery. Various engine programs (not shown) are read by reading signals from various sensors 81, 82, 83, and 84 (not shown) that detect the engine operating state such as the engine speed, intake pipe pressure (or intake air amount), and cooling water temperature. The operation of the electromagnetic drive unit 2S of the fuel injection valve 2 is controlled according to The ECU 90 controls the drive of the fuel pump 7.

  Specifically, a reference position sensor (not shown) that outputs a pulse signal every 720 ° CA according to the rotational state of the crankshaft, and a pulse signal every finer crank angle (for example, every 30 ° CA). Is provided with a rotational speed detection means 81 comprising a rotational angle sensor (not shown) for outputting A cylinder (water jacket) or the like is provided with a water temperature sensor (not shown) for detecting the cooling water temperature.

  The piston is provided with a combustion chamber wall temperature sensor 84 for detecting the temperature of the inner wall of the combustion chamber. The combustion chamber wall temperature sensor 82 is not limited to the one provided on the piston as long as it detects the temperature of the inner wall of the combustion chamber, and may be provided on the cylinder inner wall. An air flow meter 83 for detecting the intake air flow rate is disposed in the intake pipe. The exhaust pipe is provided with an air-fuel ratio sensor 84 that outputs an air-fuel ratio signal in proportion to the oxygen concentration in the exhaust gas. Further, an accelerator pedal sensor (not shown) for detecting a driver's request and the like, a throttle opening sensor, and the like are provided.

  The operating state of the engine 100 is determined based on signals from various sensors 81, 82, 83, and 84 that detect the engine speed Ne, the combustion chamber wall temperature Tc, the intake air amount F, the air-fuel ratio A / F, and the like. Is determined.

  In the present embodiment, the ECU 90 changes the detergent addition timing and the addition amount of the detergent supply device 70 according to the operating state of the engine. Specifically, the cleaning agent for the fuel injection valve 2 of the cleaning agent supply device 70 is controlled by controlling the opening and closing of the electromagnetic valve 72 according to an index value of the operating state of the engine (for example, the combustion chamber wall temperature Tc in this embodiment). Start supplying. Thereby, the supply amount of the detergent can be made variable in accordance with the operating state of the engine. Therefore, adverse effects due to excessive administration of the detergent can be prevented.

  Further, as an appropriate amount calculation method for adding the detergent to the fuel, in this embodiment, the estimated deposit amount is determined by a method of detecting the deposit adhesion state in advance or after the detection based on the operating state of the engine. Then, an appropriate amount to be added is determined from the supply amount to the fuel injection valve necessary for purifying the estimated deposit amount.

  Here, the ECU 90 shows the function executed by the above program as main means, a fuel injection control means for controlling the injection operation of the fuel injection valve 2, and an ignition control means for controlling the ignition operation of the ignition device. The cleaning agent supply device 70 includes a cleaning agent supply control means for controlling a cleaning agent addition timing and an addition amount.

  Next, the function and effect of this embodiment will be described. In this embodiment, a reservoir 71 for storing a cleaning agent is provided separately from the fuel tank 6 for storing fuel, and the fuel tank is provided by the cleaning agent supply device 70. 7 is connected to the fuel supply flow path 5 extending from the fuel injector 7 to the fuel injection valve 2, and the cleaning agent is supplied according to the estimated amount of deposit adhering to the nozzle hole 21. In addition to suppressing deterioration of fuel injection performance due to deposit adhesion, it is possible to suppress adverse effects due to excessive administration of the detergent.

  Further, in the present embodiment, the detergent supply device 70 connects the detergent supply flow path 79 from the reservoir 71 to the fuel suction portion side of the fuel pump 7 provided on the fuel supply flow path 5 side, Since the electromagnetic valve 72 that blocks and distributes the flow of the cleaning agent from the reservoir 71 to the fuel pump 7 is provided, the supply pump is provided on the side of the cleaning agent supply flow path 79 by controlling the opening and closing of the electromagnetic valve. The amount of detergent added can be controlled without any problems.

(Second Embodiment)
Hereinafter, other embodiments to which the present invention is applied will be described. In the following embodiments, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and description thereof will not be repeated.

  In the second embodiment, the cleaning agent supply flow path described in the first embodiment is replaced with a cleaning agent supply flow path 79 connected to the fuel suction portion side of the fuel pump 7, as shown in FIG. The cleaning agent supply flow path 179 is connected to the fuel discharge part side of the fuel pump 7. FIG. 2 is a configuration diagram showing the configuration of the detergent addition device of the present embodiment.

  As shown in FIG. 2, the detergent supply device 170 includes a reservoir 171 and a pressure pump 73. The pumping pump 73 is a pump having a known structure that guides the detergent from the reservoir 171 and pumps it to the discharge part side of the fuel pump 7. The pressure feed pump 73 is driven and controlled by the ECU 90. In the cleaning agent supply pipe 79, the outlet portion on the downstream side of the cleaning agent flow is connected to the fuel suction portion side of the fuel pump 7. On the other hand, the inlet of the upstream side of the flow of the detergent is connected to the reservoir 171, and the reservoir 171 and the pressure pump 73 are disposed outside the fuel tank 106. The reservoir 171 is configured to be fitted with a cap 171a as a lid, and the cleaning agent can be replenished by opening and closing the cap 79a. It should be noted that the storage 171 is installed in the engine room.

  Even in such a configuration, the cleaning agent supply device 171 connects the cleaning agent supply channel 179 from the reservoir 171 to the fuel discharge unit side of the fuel pump 7 provided on the fuel supply channel 5 side. , Because it has a pressure feed pump 73 that pumps the detergent guided from the reservoir 171 toward the fuel discharge part side of the fuel pump 7, the amount of addition and addition of the detergent are controlled by controlling the drive of the pressure feed pump 73. Timing can be controlled.

(Third embodiment)
In the third embodiment, as shown in FIGS. 3 and 7, the deposit adhesion state is preliminarily determined based on the operating state of the engine as a method for calculating an appropriate amount for adding the detergent to the fuel described in the first embodiment. The deposit estimation amount is determined by the detection method. FIG. 3 is a flowchart showing the control processing according to the present embodiment, and is a flowchart showing the control processing for changing the supply amount of the detergent according to the operating state. FIG. 4 is a graph showing the relationship between the operating state represented by the load and the rotational speed of the internal combustion engine and the generation rate of deposits attached to the injection hole portion of the fuel injection valve. FIG. 5 is a graph showing the relationship between the operating state represented by the load factor and the rotational speed of the internal combustion engine and the inner wall temperature of the combustion chamber. FIG. 6 is a graph showing the relationship between the deviation rate between the target air-fuel ratio and the actual air-fuel ratio and the amount of deposit attached to the injection hole of the fuel injection valve. FIG. 7 is a flowchart for explaining the control process in FIG. 3, and is a flowchart showing the control process for obtaining the estimated amount of deposit.

  As shown in FIG. 3, in S310 (S is a step), various sensors 81, 82, 83, 84 for detecting the engine speed Ne, the combustion chamber wall temperature Tc, the intake air amount F, the air-fuel ratio A / F, etc. The engine operating state is read based on the signal.

  In S320, an estimated deposit amount (hereinafter referred to as deposit amount) Wd is calculated based on the read operating state of the engine. Specifically, the operating state of the engine is divided into operating regions A1, A2, and A33 in the deposit generation amount map shown in FIG. 4, and the operation history is accumulated by setting the weight coefficient for deposit adhesion in the operating region. Ask for it. A method for detecting the deposit amount Wd in advance will be described later.

  In S330, it is determined whether or not the determined deposit amount Wd exceeds a predetermined value Wdo (Wd> Wdo). If the deposit amount Wd exceeds the predetermined value Wdo, the process proceeds to S340. On the contrary, if the deposit amount Wd is equal to or less than the predetermined value Wdo, it is determined that the deposit attached to the injection hole 21 is not so large as to affect the injection performance of the fuel injection valve 2, and the process returns to S310, where the deposit amount Wd Is repeated until a predetermined value Wdo is exceeded.

  In S340, if it is determined in S330 that the deposit amount Wd exceeds the predetermined value Wdo, an index value of the engine operating state for determining the addition timing of the detergent is estimated. In this embodiment, the temperature Tc of the combustion chamber wall is employed as an index value for the operating state of the engine.

  In general, when the cleaning agent is supplied to the fuel injection valve 2 and directly supplied to the combustion chamber, if the cleaning agent adheres to the piston surface constituting the inner wall of the combustion chamber, the cleaning agent may cause a combustion chamber deposit. There is. Further, it has been found that the detergent disappears without depositing when the temperature reaches a predetermined temperature To (250 ° C.) or higher. For this reason, it is preferable to determine the addition timing of the cleaning agent by comparing the temperature Tc of the cleaning agent, particularly the temperature Tc of the combustion chamber wall that may cause a combustion chamber deposit, with the predetermined temperature To.

  Therefore, in S350, it is determined whether or not the combustion chamber wall temperature Tc exceeds a predetermined temperature To (Tc> To). If the combustion chamber wall temperature Tc exceeds the predetermined temperature To, the process proceeds to S360, and the addition of the detergent is started. Conversely, if the combustion chamber wall temperature Tc is the predetermined temperature To, the process returns to S310 and is repeated until the combustion chamber wall temperature Tc exceeds the predetermined temperature To until the engine is in an operating state. The combustion chamber wall temperature Tc is obtained by a method of estimation based on the operating state of the engine and a map as shown in FIG. Note that the method is not limited to the method of estimating the combustion chamber wall temperature Tc based on the map, but may be a method of detecting the combustion chamber wall temperature Tc by the combustion chamber wall temperature sensor 82.

  When the addition of the cleaning agent is started in S360, in S370, the deposit amount Wd adhered to the injection hole 21 purified by injecting the fuel with the addition of the cleaning agent from the injection hole 21 of the fuel injection valve 2 is a predetermined value. It is determined whether or not it is less than Wdo (Wd <Wdo). Specifically, a difference in state occurs between the actual air-fuel ratio A / Fob that is affected by deposit adhesion and the target air-fuel ratio A / Fa that is calculated from the operating state of the engine. The rate K {K = (A / Fa) / (A / Fob)} is calculated, and the deposit amount Wd is estimated based on the air-fuel ratio deviation rate K and the map shown in FIG. The details of the method for estimating the deposit amount Wd from the air-fuel ratio deviation rate K will be described later in the post-detection method in the fourth embodiment.

  If the deposit amount Wd purified and reduced by the addition of the detergent becomes less than the predetermined value Wdo, the process proceeds to S380, and the addition of the detergent is stopped. Conversely, if the deposit amount Wd is equal to or greater than the predetermined value Wdo, the addition of the detergent is continued.

  Here, a method for detecting in advance the deposit amount Wd related to the control processing in S320 will be described with reference to FIG. In S321, it is determined which operating region Ax the engine operating state that has been read is shown in the map of FIG. In FIG. 4, a plurality (four in this embodiment) of operation areas Ax are divided into operation areas A1, operation areas A2, operation areas A3, and areas that are not any of A1 to A3. Within each operation region, deposit generation speeds are different, and each operation region A1 to A3 has generation speeds W1, W2, and W3 (W1> W2> W3), respectively.

  If the operation area Ax is A1, the process proceeds to S322, and the generated speed W1 and the operation time of the history are integrated. If the operation area Ax is A2, the process proceeds to S323, where the generated speed W2 and the operation time of the history are integrated. If the operation area Ax is A3, the process proceeds to S324, and the generated speed W3 and the operation time of the history are integrated. If the operation area Ax is an area that is not any of A1 to A3, the process proceeds to S324 and is not integrated as, for example, zero.

  In S326, the deposit amount Wd is estimated by integrating all the deposit amounts Wd1 to Wd4 for each operation region accumulated in the control processing of S322 to S325.

  Here, if the function executed by the program is indicated by main means, the ECU 90 divides the engine operating state into operating regions A1, A2, and A3 according to the generation speed W as a deposit generation amount index value. Classification means for performing, weighting coefficient setting means for setting weighting coefficients W1, W2, and W3 corresponding to the generated speed W to the classified operation areas A1, A2, and A3, and an operation area A1 that is detected in the engine operating state, Storage means for storing the history of A2 and A3.

  By configuring in this way, the deposit amount Wd is a weight coefficient W1 of deposit adhesion for each of the operation areas A1, A2, and A3 divided into a map (see FIG. 4) of the deposit generation speed W according to the operation state. It is obtained by integrating operation histories based on the settings of W2 and W3. Therefore, even if the deposit amount Wd is such that the deposit adhesion does not affect the fuel injection performance, it can be detected in advance.

  In addition, when the ECU 90 indicates the function executed by the above-described program as a main means, the cleaning chamber inner wall temperature Tc as an index value of the detected operating state of the internal combustion engine is compared with the cleaning agent in the combustion chamber. And a cleaning agent addition timing determining means for determining a cleaning agent addition timing based on a predetermined temperature To which is not a deposit.

  With this configuration, the cleaning agent can be added when the cleaning agent is in an operating state of the engine that does not deposit in the combustion chamber. Therefore, deterioration of fuel injection performance due to deposit adhesion can be suppressed, and adverse effects due to the administration of the detergent can be prevented.

(Fourth embodiment)
In the fourth embodiment, instead of the control process S320 described in the third embodiment, a post-detection method for estimating the deposit amount Wd is used as shown in FIG. FIG. 8 is a flowchart showing a control process for obtaining an estimated amount of deposit according to the present embodiment.

  As shown in FIG. 8, in S402, the deposit amount Wd is calculated from the deviation rate K of the air-fuel ratio A / F by the following method.

In the relationship between the deviation ratio K of the air-fuel ratio A / F and the deposit amount Wd in FIG.
K = (A / Fa) / (A / Fob) is obtained from the actual measurement value A / Fob detected by the air-fuel ratio sensor 84 and the target air-fuel ratio A / Fa calculated from the operating state of the engine.

  Even with this configuration, the same effect as that of the third embodiment can be obtained.

(Fifth embodiment)
In the fourth embodiment, when the cleaning agent described in the third embodiment is in an operating state of the engine that does not become a deposit in the combustion chamber, the cleaning agent is not added, as shown in FIG. The operation state is changed to an operation condition in which the detergent does not deposit in the combustion chamber. FIG. 9 is a flowchart showing control processing according to the present embodiment.

  As shown in FIG. 9, when it is determined in the control process of S350 that the combustion chamber inner wall temperature Tc is equal to or lower than the predetermined temperature To, the process proceeds to S590.

  In S590, the ignition timing CAi is changed based on the map shown in FIG. 10, and the operation condition is changed to an operating condition in which the combustion chamber wall temperature Tc exceeds the predetermined temperature To.

  Here, the ECU 90 includes an operating condition changing means for changing the operating condition of the engine so that the combustion chamber wall temperature Tc satisfies a predetermined temperature To as the permission index value.

  By comprising in this way, the addition amount of the detergent according to the estimated deposit amount Wd can be promptly supplied to the fuel injection valve 2 at an appropriate amount in a timely manner. Therefore, deterioration of the fuel injection performance due to deposit adhesion can be prevented.

  The map is not limited to the map related to the engine speed Ne (see FIG. 10), but may be related to the engine load factor.

It is a block diagram which shows the structure of the detergent addition apparatus of the 1st Embodiment of this invention. It is a block diagram which shows the structure of the detergent addition apparatus of 2nd Embodiment. It is a figure which shows the control processing concerning 3rd Embodiment, Comprising: It is a flowchart which shows the control processing which makes the supply amount of a detergent variable according to an operating state. It is a graph which shows the relationship between the driving | running state represented by the load and rotation speed of an internal combustion engine, and the generation speed of the deposit adhering to the nozzle hole part of a fuel injection valve. It is a graph which shows the relationship between the driving | running state represented by the load factor and rotation speed of an internal combustion engine, and the inner wall temperature of a combustion chamber. It is a graph which shows the relationship between the deviation rate of a target air fuel ratio and an actual air fuel ratio, and the deposit amount adhering to the nozzle hole part of a fuel injection valve. FIG. 4 is a diagram illustrating a control process in FIG. 3, and is a flowchart showing a control process for obtaining an estimated amount of deposit. It is a flowchart which shows the control processing which calculates | requires the estimated amount of the deposit concerning 4th Embodiment. It is a flowchart which shows the control processing concerning 5th Embodiment. It is a graph which shows the relationship between the inner wall temperature of a combustion chamber, the rotation speed of an internal combustion engine, and ignition timing. It is a graph which shows the relationship between the inner wall temperature of a combustion chamber, the load factor of an internal combustion engine, and ignition timing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel injection apparatus 2 Fuel injection valve 2b Valve part 2S Electromagnetic drive part 21 Injection hole (injection part)
5 Fuel supply piping (fuel supply flow path)
6 Fuel tank 7 Fuel pump 8 Fuel distribution pipe 70 Cleaning agent supply device 71 Storage unit 72 Solenoid valve 79 Cleaning agent supply pipe (cleaning agent supply flow path)
79a Cap 81 Rotational speed sensor (Rotational speed detection means)
82 Combustion indoor wall temperature sensor (combustion indoor wall temperature detection means)
83 Air flow meter (intake air flow rate detection means)
84 Air-fuel ratio sensor (air-fuel ratio detection means)
90 ECU (control means)

Claims (8)

A combustion chamber in a cylinder, and a fuel injection valve that injects and supplies fuel to the combustion chamber, and is used for a combustible mixture in which air and fuel are mixed or an internal combustion engine that is ignited by ignition;
In the cleaning agent addition apparatus, the cleaning agent for purifying deposits adhering to the nozzle hole portion of the fuel injection valve is mixed with the fuel, and the fuel added with the cleaning agent is supplied to the fuel injection valve.
A reservoir that is provided separately from a fuel tank that stores fuel, and stores the cleaning agent;
A cleaning agent supply channel from the reservoir is connected to a fuel supply channel from the fuel tank to the fuel injection valve, and the cleaning agent is supplied in accordance with an estimated amount of deposit adhering to the nozzle hole. And a supply device for performing the cleaning agent addition device. The fuel supply passage is provided with a fuel pump that sucks up fuel stored in the fuel tank and discharges the fuel toward the fuel injection valve between the fuel tank and the fuel injection valve. ,
The supply device includes an electromagnetic valve that connects the cleaning agent supply flow path from the reservoir to a fuel suction portion side of the fuel pump, and shuts off and distributes the flow of the cleaning agent from the storage to the fuel pump. The cleaning agent addition apparatus according to claim 1, wherein the cleaning agent addition apparatus is provided. The fuel supply passage is provided with a fuel pump that sucks up fuel stored in the fuel tank and discharges the fuel toward the fuel injection valve between the fuel tank and the fuel injection valve. ,
The supply device connects the cleaning agent supply flow path from the reservoir to the fuel discharge portion side of the fuel pump, and pumps the cleaning agent guided from the reservoir toward the fuel discharge portion side of the fuel pump. The cleaning agent addition apparatus according to claim 1, further comprising: a pressure feed pump configured to perform the cleaning operation. The supply device includes a control means for controlling the addition timing and the addition amount of the detergent based on the estimated deposit amount,
The detergent addition apparatus according to any one of claims 1 to 3, wherein the control means determines the estimated deposit amount based on an operating state of the internal combustion engine. The control means includes
Classifying means for classifying the operating state of the internal combustion engine into operating regions according to a deposit generation amount index value;
Weighting factor setting means for setting a weighting factor corresponding to the deposit generation amount index value in the divided operation region;
The cleaning agent addition apparatus according to claim 4, further comprising storage means for storing a history of the operation region detected in an operation state of the internal combustion engine.   The control means estimates the deposit based on an actual internal combustion engine state index value detected in an operating state of the internal combustion engine affected by deposit adhesion and a target internal combustion engine state index value in the operating state of the internal combustion engine. The detergent addition device according to claim 4, wherein the amount is determined.   The control means determines the cleaning agent addition timing based on the detected index value of the operating state of the internal combustion engine and the permission index value which is compared with the index value and the cleaning agent does not deposit in the combustion chamber. The cleaning agent addition apparatus according to any one of claims 4 to 6, further comprising a cleaning agent addition timing determination unit. The control means, so that the index value of the operating state of the internal combustion engine satisfies the permission index value,
The cleaning agent addition apparatus according to claim 7, further comprising an operation condition changing unit that changes an operation condition of the internal combustion engine.

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