JP2009133211A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable suppression of deposit-accumulation into a combustion chamber, in a control device of an internal combustion engine. <P>SOLUTION: By an ECU 53, timing and quantity of fuel injection by an injector 43 are set in accordance with operation conditions of the internal combustion engine, and the injector 43 is controlled according to the set timing and quantity of the fuel injection. In this case, a cumulative amount of operation of the internal combustion engine operated by alcohol-blended fuel is detected, and timing for fuel injection is set so that when the detected cumulative-amount of operation has exceeded a preset specified value, the spray of the alcohol-blended fuel injected by the injector 43 is directed to the top face of a piston 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine that can be operated with an alcohol-mixed fuel in which alcohol is mixed with fuel.

  2. Description of the Related Art In recent years, so-called multi-fuel internal combustion engines have been adopted in which a plurality of types of fuels having different fuel properties are used in an internal combustion engine and the respective advantages are complemented and the advantages are mutually complemented. A vehicle equipped with this multi-fuel internal combustion engine is generally called a flexible fuel vehicle (FFV). One example is the use of gasoline fuels and alcohol fuels such as ethanol alone or in combination to meet the required performance to improve the internal combustion engine emission performance and control consumption of fossil fuels such as gasoline fuel. Those that improve performance are known.

  However, in a cylinder injection internal combustion engine that directly injects fuel into a combustion chamber, an injector that injects fuel is disposed in the cylinder head, and the tip of the injector faces the combustion chamber. The tip of the injector tends to be relatively hot. When the tip temperature of the injector becomes high, high-boiling components (aromatic components) in gasoline tend to adhere or remain around the nozzle part at the tip of the injector, and aggregate and adhere as deposits (fuel carbide) in the nozzle part. . Then, the amount of fuel injected from the injector is reduced, leading to a reduction in engine output.

  Therefore, for example, in the engine control apparatus described in Patent Document 1 below, the switching control means sends a signal to the switching means in accordance with the tip temperature of the injector, and the operation using the main fuel and the alcohol fuel are performed. When the injector tip temperature is at a temperature where the possibility of deposit deposition is high, switching to operation using alcohol fuel with a lower high boiling point component than the main fuel, the deposit It avoids sticking to the tip of the injector.

JP 2006-242084 A

  However, since alcohol has better vaporization characteristics than gasoline, it is less likely to vaporize immediately after being injected from the injector and reach the wall of the combustion chamber as a non-volatile component. Therefore, deposits easily accumulate on the wall surface of the combustion chamber, and alcohol easily ignites. Therefore, deposits deposited on the wall surface of the combustion chamber are ignited by alcohol, and pregure easily occurs. In addition, since alcohol has a high latent heat of vaporization, the temperature of the combustion chamber tends to decrease even when the internal combustion engine is under high load, and deposits are likely to accumulate particularly on the top surface of the piston due to oil.

  An object of the present invention is to provide a control device for an internal combustion engine that can suppress the accumulation of deposits in a combustion chamber.

  In order to solve the above-described problems and achieve the object, a control device for an internal combustion engine according to the present invention includes a fuel injection unit capable of injecting alcohol fuel into a combustion chamber or an intake port of an internal combustion engine, and an operating state of the internal combustion engine. A fuel injection timing setting means for setting a fuel injection timing by the fuel injection means according to the fuel injection timing, a fuel injection control means for controlling the fuel injection means based on the fuel injection timing set by the fuel injection timing setting means, In the control apparatus for an internal combustion engine, provided is an alcohol fuel operation cumulative amount detection means for detecting an operation cumulative amount of the internal combustion engine using alcohol fuel, and the fuel injection timing setting means is detected by the alcohol fuel operation cumulative amount detection means. When the accumulated operation amount exceeds a predetermined value set in advance, the spray of alcohol fuel injected by the fuel injection means Set the time facing the top surface, it is characterized in.

  In the control apparatus for an internal combustion engine according to the present invention, the operation cumulative amount of the internal combustion engine by the alcohol fuel detected by the alcohol fuel operation cumulative amount detection means is an operation continuation time of the internal combustion engine by the alcohol fuel. .

  In the control apparatus for an internal combustion engine according to the present invention, the operation cumulative amount of the internal combustion engine by the alcohol fuel detected by the alcohol fuel operation cumulative amount detection unit is a cumulative injection amount of the alcohol fuel injected by the fuel injection unit. It is characterized by.

  In the control device for an internal combustion engine of the present invention, the alcohol fuel is a mixed fuel of alcohol and gasoline, and the operation cumulative amount of the internal combustion engine by the alcohol fuel detected by the alcohol fuel operation cumulative amount detection means is preset. It is characterized by the cumulative amount of operation with a fuel with an alcohol concentration or higher.

  In the control device for an internal combustion engine of the present invention, the alcohol fuel operation cumulative amount detection means detects the operation cumulative amount of the internal combustion engine by alcohol fuel when the internal combustion engine is at a predetermined temperature or higher. It is characterized by.

  In the control apparatus for an internal combustion engine according to the present invention, the fuel injection timing setting means takes in the fuel injection timing by the fuel injection means when the operation cumulative amount detected by the alcohol fuel operation cumulative amount detection means exceeds a predetermined value. It is set in the first half of the process.

  In the control device for an internal combustion engine of the present invention, a fuel injection amount setting means for setting a fuel injection amount by the fuel injection means in accordance with an operating state of the internal combustion engine is provided, and the fuel injection timing setting means is configured to perform the alcohol fuel operation. The fuel injection timing by the fuel injection unit when the cumulative operation amount detected by the cumulative amount detection unit exceeds a predetermined value, or when the fuel injection amount set by the fuel injection amount setting unit exceeds a predetermined value set in advance. Is set to the first half of the intake stroke and the second half of the compression stroke.

  According to the control apparatus for an internal combustion engine of the present invention, the alcohol fuel operation cumulative amount detection means for detecting the operation cumulative amount of the internal combustion engine by alcohol fuel is provided, and the fuel injection timing setting means is detected by the alcohol fuel operation cumulative amount detection means When the accumulated operation amount exceeds a predetermined value set in advance, the alcohol fuel spray injected by the fuel injection means is set at a timing when it is directed to the piston top surface, so that the alcohol fuel collides with the piston top surface. Thus, the deposit adhering to the top surface of the piston is washed away by alcohol, and deposit accumulation in the combustion chamber can be suppressed.

  Embodiments of an internal combustion engine control apparatus according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example.

  FIG. 1 is a schematic configuration diagram illustrating a control device for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a flowchart illustrating deposit flush control by the control device for the internal combustion engine according to the present embodiment, and FIG. FIG. 4 is a schematic diagram showing fuel injection by the injection timing in the deposit flush control.

  The control apparatus for an internal combustion engine according to the present embodiment uses a mixture of a plurality of types of fuels having different fuel properties, here, alcohol fuel and gasoline fuel. As shown in FIG. 1, a cylinder head 12 is fastened on a cylinder block 11, and pistons 14 are fitted to a plurality of cylinder bores 13 formed on the cylinder block 11 so as to be movable up and down. A crankcase 15 is fastened to the lower part of the cylinder block 11, and a crankshaft 16 is rotatably supported in the crankcase 15. Each piston 14 is connected to the crankshaft 16 via a connecting rod 17. Has been.

  The combustion chamber 18 is constituted by the wall surface of the cylinder bore 13 in the cylinder block 11, the lower surface of the cylinder head 12, and the top surface of the piston 14, and the combustion chamber 18 has a high central portion at the upper portion (lower surface of the cylinder head 12). It has a pent roof shape that is slanted. An intake port 19 and an exhaust port 20 are formed on the upper portion of the combustion chamber 18, that is, the lower surface of the cylinder head 12, and the intake valve 19 and the exhaust valve 20 are opposed to the intake port 19 and the exhaust port 20. The lower end portions of 22 are respectively positioned. The intake valve 21 and the exhaust valve 22 are supported by the cylinder head 12 so as to be movable in the axial direction, and are urged and supported in a direction (upward in FIG. 1) for closing the intake port 19 and the exhaust port 20. ing. An intake cam shaft 23 and an exhaust cam shaft 24 are rotatably supported on the cylinder head 12, and the intake cam and the exhaust cam are in contact with upper ends of the intake valve 21 and the exhaust valve 22.

  Although not shown, the crankshaft sprocket fixed to the crankshaft 16 and the camshaft sprockets respectively fixed to the intake camshaft 23 and the exhaust camshaft 24 are wound with endless timing chains. The crankshaft 16, the intake camshaft 23, and the exhaust camshaft 24 can be interlocked.

  Accordingly, when the intake camshaft 23 and the exhaust camshaft 24 rotate in synchronization with the crankshaft 16, the intake cam and the exhaust cam move up and down the intake valve 21 and the exhaust valve 22 at a predetermined timing. The exhaust port 20 can be opened and closed to allow the intake port 19 and the combustion chamber 18 to communicate with the combustion chamber 18 and the exhaust port 20. In this case, the intake camshaft 23 and the exhaust camshaft 24 are set to rotate once (360 degrees) while the crankshaft 16 rotates twice (720 degrees). Therefore, the engine performs four strokes of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke while the crankshaft 16 rotates twice. At this time, the intake camshaft 23 and the exhaust camshaft 24 rotate once. Will be.

  The valve mechanism of the engine is a variable intake valve timing mechanism (VVT: Variable Valve Timing-intelligent) 25 that controls the intake valve 21 and the exhaust valve 22 at an optimal opening / closing timing according to the operating state. The intake variable valve mechanism 25 is configured by providing a VVT controller 26 at the shaft end of the intake camshaft 23, and the hydraulic pressure from the oil control valve 27 is supplied to an advance chamber and a retard chamber (not shown) of the VVT controller 26. By acting on this, the phase of the intake camshaft 23 with respect to the cam sprocket can be changed, and the opening / closing timing of the intake valve 21 can be advanced or retarded. In this case, the intake variable valve mechanism 25 advances or retards the opening / closing timing while keeping the operating angle (opening period) of the intake valve 21 constant. The intake camshaft 23 is provided with a cam position sensor 28 for detecting the rotational phase.

  A surge tank 30 is connected to the intake port 19 via an intake manifold 29, and an intake pipe 31 is connected to the surge tank 30. An air cleaner 32 is attached to an air intake port of the intake pipe 31. . An electronic throttle device 34 having a throttle valve 33 is provided on the downstream side of the air cleaner 32.

  An exhaust pipe 36 is connected to the exhaust port 20 via an exhaust manifold 35, and the exhaust pipe 36 has a three-way catalyst 37 for purifying harmful substances contained in the exhaust gas and a NOx occlusion reduction type catalyst 38. Is installed. This three-way catalyst 37 simultaneously purifies HC, CO, and NOx contained in the exhaust gas by an oxidation-reduction reaction when the air-fuel ratio (exhaust air-fuel ratio) is stoichiometric. The NOx occlusion reduction type catalyst 38 is in a rich combustion region or stoichiometric combustion region where the NOx contained in the exhaust gas is temporarily stored when the air-fuel ratio (exhaust air-fuel ratio) is lean, and the oxygen concentration in the exhaust gas is reduced. Sometimes, the stored NOx is released and NOx is reduced by the added fuel as a reducing agent.

  An exhaust gas recirculation passage (EGR passage) 39 is provided between the downstream side of the surge tank 30 in the intake pipe 31 and the upstream side of the three-way catalyst 37 in the exhaust pipe 36. Are provided with an EGR valve 40 and an EGR cooler 41. Further, an EGR gas temperature sensor 42 for detecting the temperature of the EGR gas is provided on the EGR passage 39 closer to the intake pipe 31 than the EGR valve 40.

  The cylinder head 12 is provided with an injector (fuel injection means) 43 that directly injects fuel into the combustion chamber 18. The injector 43 is located on the intake port 19 side and is inclined downward by a predetermined angle from the horizontal upper end. Are arranged. The injector 43 attached to each cylinder is connected to a delivery pipe 44, and a high pressure fuel pump 46 is connected to the delivery pipe 44 via a high pressure fuel supply pipe 45. The high pressure fuel pump 46 is supplied with a low pressure fuel supply. A low pressure fuel pump (feed pump) 49 in the fuel tank 48 is connected via a pipe 47. Accordingly, the low-pressure fuel pump 49 pressurizes the fuel in the fuel tank 48 to a predetermined low pressure and supplies it to the low-pressure fuel supply pipe 47, and the high-pressure fuel pump 46 supplies the low-pressure fuel in the low-pressure fuel supply pipe 47 to a predetermined high pressure. The fuel can be pressurized and supplied to the delivery pipe 44 via the high-pressure fuel supply pipe 45, and the injector 43 can inject the high-pressure fuel in the delivery pipe 44 into the combustion chamber 18. The cylinder head 12 is provided with a spark plug 50 that is located above the combustion chamber 18 and ignites the air-fuel mixture.

  The vehicle is equipped with an electronic control unit (ECU) 53, which can control the fuel injection timing of the injector 43, the ignition timing of the spark plug 50, and the like. The fuel injection amount, injection timing, ignition timing, and the like are determined based on engine operating conditions such as temperature, throttle opening, accelerator opening, engine speed, and coolant temperature.

  That is, an airflow sensor 54 and an intake air temperature sensor 55 are mounted on the upstream side of the intake pipe 31, and the measured intake air amount and intake air temperature are output to the ECU 53. The electronic throttle device 34 is provided with a throttle position sensor 56, and the accelerator pedal is provided with an accelerator position sensor 57, which outputs the current throttle opening and accelerator opening to the ECU 53. The crankshaft 16 is provided with a crank angle sensor 58 and outputs the detected crank angle to the ECU 53. The ECU 53 discriminates an intake stroke, a compression stroke, an expansion stroke, an exhaust stroke in each cylinder based on the crank angle, and an engine. Calculate the number of revolutions. Further, the cylinder block 11 is provided with a water temperature sensor 59 and outputs the detected engine cooling water temperature to the ECU 53. The cylinder block 11 is provided with a knock sensor 60 and outputs a detected knocking signal to the ECU 53.

An air-fuel ratio (A / F) sensor 61 is provided upstream of the three-way catalyst 37 in the exhaust pipe 36, and an oxygen (O ₂ ) sensor 62 is provided downstream of the three-way catalyst 37. The A / F sensor 61 and the O ₂ sensor 62 detect the exhaust air / fuel ratio (oxygen amount) of the exhaust gas exhausted from the combustion chamber 18 through the exhaust port 20 and the exhaust manifold 35 to the exhaust pipe 36, and detect the detected exhaust air. The fuel ratio is output to the ECU 53. The ECU 53 corrects the fuel injection amount by feeding back the exhaust air-fuel ratio detected by the A / F sensor 61 and the O ₂ sensor 62 and comparing it with the target air-fuel ratio set according to the engine operating state.

  The fuel tank 48 stores a mixed fuel of alcohol and gasoline, and is provided with a remaining amount sensor 63 for detecting the remaining amount of the stored mixed fuel. Output. Further, the fuel tank 48 is provided with a concentration sensor 64 for detecting the alcohol concentration in the mixed fuel stored in the fuel tank 48, and outputs the detected alcohol concentration in the mixed fuel to the ECU 53.

  Further, the ECU 53 can control the intake variable valve mechanism 25 based on the engine operating state. That is, when the temperature is low, the engine is started, the engine is idle, or the load is light, the exhaust gas blows back into the intake port 19 or the combustion chamber 18 by eliminating the overlap between the exhaust valve 22 closing timing and the intake valve 21 opening timing. Reduce the amount to enable stable combustion and improved fuel efficiency. Further, at the time of medium load, by increasing the overlap, the internal EGR rate is increased to improve the exhaust gas purification efficiency, and the pumping loss is reduced to improve the fuel consumption. Further, at the time of high-load low-medium rotation, the closing timing of the intake valve 21 is advanced, thereby reducing the amount of intake air that blows back to the intake port 19 and improving the volume efficiency. At the time of high load and high rotation, the closing timing of the intake valve 21 is retarded in accordance with the rotation speed, so that the timing is adjusted to the inertial force of the intake air and the volume efficiency is improved.

  By the way, as described above, the internal combustion engine of the present embodiment can use an alcohol-mixed fuel obtained by mixing a gasoline fuel with an alcohol fuel such as ethanol at a predetermined ratio. It is intended to improve environmental performance such as fossil fuel consumption control. However, since alcohol has better vaporization characteristics than gasoline, it is unlikely to vaporize immediately after being injected into the combustion chamber 18 and reach the wall surface as a non-volatile component. Therefore, deposits easily accumulate on the wall surface of the combustion chamber 18 and alcohol is easily ignited. Therefore, deposits deposited on the wall surface of the combustion chamber are ignited by alcohol, and pregure is likely to occur.

  Therefore, in the control device for the internal combustion engine of the present embodiment, the ECU 53 as the fuel injection control means sets the fuel injection timing by the injector 43 according to the operating state of the internal combustion engine (fuel injection timing setting means) as described above. In addition, the fuel injection amount by the injector 43 can be set (fuel injection amount setting means), and the injector 43 can be controlled based on the set fuel injection timing and fuel injection amount. The ECU 53 detects the accumulated operation amount of the internal combustion engine using the alcohol-mixed fuel (alcohol fuel operation accumulated amount detecting means), and when the detected accumulated operation amount exceeds a predetermined value, the injector 43 injects the fuel. The fuel injection timing is set so that the spray of the alcohol mixed fuel to be directed faces the top surface of the piston 14.

  In this case, the cumulative operation amount of the internal combustion engine using the alcohol-mixed fuel is used as the operation duration time of the internal combustion engine using the alcohol-mixed fuel. The cumulative operation amount of the internal combustion engine using alcohol fuel may be the cumulative injection amount of the alcohol mixed fuel injected by the injector 43, or the cumulative operation amount of the mixed fuel having a predetermined alcohol concentration or higher.

  Then, the ECU 53 detects the accumulated operation amount of the internal combustion engine by the alcohol-mixed fuel when the internal combustion engine is equal to or higher than a predetermined temperature set in advance, that is, when the engine cooling water temperature detected by the water temperature sensor 59 is equal to or higher than the predetermined temperature. I have to.

  Further, the ECU 53 sets the fuel injection timing by the injector 43 in the first half of the intake stroke when the alcohol mixed fuel operation cumulative amount exceeds a predetermined value. In this case, the ECU 53 sets the fuel injection timing by the injector 43 to the first half of the intake stroke and the second half of the compression stroke when the alcohol fuel operation cumulative amount exceeds a predetermined value, and when the set fuel injection amount exceeds a predetermined value. Is set.

  Here, the deposit flush control by the control device for the internal combustion engine of the present embodiment will be described based on the flowchart of FIG.

  In the deposit flush control by the control device for the internal combustion engine of the present embodiment, as shown in FIG. 2, the concentration sensor 64 detects the alcohol concentration in the mixed fuel stored in the fuel tank 48, as shown in FIG. The detected alcohol concentration is output to the ECU 53, and in step S12, the ECU 53 determines whether or not the detected alcohol concentration is higher than a predetermined alcohol concentration A% (for example, 50%) set in advance. That is, the alcohol concentration of the mixed fuel supplied to the fuel tank 48 may vary, while the mixed fuel having a low alcohol concentration has a low deposit washing effect. Here, if it is determined that the alcohol concentration in the mixed fuel stored in the fuel tank 48 is higher than the predetermined alcohol concentration A%, in step S13, the ECU 53 presets the engine coolant temperature detected by the water temperature sensor 59. It is determined whether it is higher than a predetermined engine coolant temperature H ° C (for example, 70 ° C). That is, when the internal combustion engine is not completely warmed up, the deposit washing effect is low. Here, if it is determined that the engine coolant temperature is higher than the predetermined engine coolant temperature H ° C., the cumulative operation time (operation continuation time) T is started to be counted in step S14.

  In step S15, the ECU 53 determines whether or not the cumulative operation time T is longer than a predetermined cumulative operation time B set in advance. That is, if the cumulative operation time T is long, a large amount of deposit accumulates on the top surface of the piston 14, which may cause a problem in combustion or the like. If it is determined that the cumulative operation time T is longer than the predetermined cumulative operation time B, the fuel injection timing is reset to the first half of the intake stroke in step S16.

  On the other hand, in step S12, it is determined that the alcohol concentration in the mixed fuel stored in the fuel tank 48 is not higher than the predetermined alcohol concentration A%, or in step S13, the engine cooling water temperature is higher than the predetermined engine cooling water temperature H ° C. If it is determined that the accumulated operation time T is not longer than the predetermined accumulated operation time B in step S15, the accumulated operation time (operation duration) T is reset (T = 0) in step S25. ) In step S26, normal fuel injection timing control is executed. That is, as shown in FIG. 3, the ECU 53 injects fuel into the combustion chamber 18 by the injector 43 in the latter half of the intake stroke in which the piston 14 descends in the A direction. At this time, the fuel spray injected from the injector 43 does not collide with the top surface (cavity) 14 a of the piston 14.

  In step S17, the ECU 53 determines whether the total fuel injection amount set by the intake air amount or the like can be injected only in the first half of the intake stroke. That is, when the driver depresses the accelerator pedal and the vehicle is accelerating, the fuel injection amount is increased to a large amount, and the total fuel injection amount may not be injected only in the first half of the intake stroke. If it is determined that the total fuel injection amount cannot be injected only in the first half of the intake stroke, the fuel injection timing is reset to two-stage injection in the first half of the intake stroke and the second half of the compression stroke in step S18, and then step S19. Migrate to On the other hand, if it is determined that the total fuel injection amount can be injected only in the first half of the intake stroke, the fuel injection timing remains the first half of the intake stroke, and the process proceeds to step S19.

  In step S19, fuel injection timing control is executed at the reset injection timing. That is, as shown in FIG. 4, the ECU 53 injects fuel into the combustion chamber 18 in the first half of the intake stroke in which the piston 14 descends in the A direction by the injector 43 and in the latter half of the compression stroke in which the piston 14 rises in the B direction. Then, fuel is injected into the combustion chamber 18. At this time, the fuel spray injected from the injector 43 collides with the top surface (cavity) 14a of the piston 14, and the deposit attached to the top surface 14a of the piston 14 is washed away.

  In step S20, the cumulative operation time T is reset (T = 0), and in step S21, the cumulative fuel injection amount F in the reset execution period of the fuel injection timing control is started. In step S22, the ECU 53 determines whether or not the cumulative fuel injection amount F exceeds a predetermined cumulative fuel injection amount C set in advance, and the cumulative fuel injection amount F exceeds the predetermined cumulative fuel injection amount C. If it is determined that it is not, the process returns to step S16 and the process is repeated. On the other hand, when the ECU 53 determines that the cumulative fuel injection amount F has exceeded the predetermined cumulative fuel injection amount C, the ECU 53 resets the cumulative fuel injection amount F (F = 0) in step S23, and in step S24. Return to normal fuel injection timing control.

  Thus, in the control device for the internal combustion engine of the present embodiment, the ECU 53 sets the fuel injection timing and the fuel injection amount by the injector 43 according to the operating state of the internal combustion engine, and the set fuel injection timing and fuel are set. The injector 43 can be controlled based on the injection amount. At this time, when the cumulative operation amount of the internal combustion engine using the alcohol-mixed fuel is detected and the detected cumulative operation amount exceeds a predetermined value, the injector 43 is detected. The fuel injection timing is set so that the spray of the alcohol-mixed fuel injected by the nozzle is directed toward the top surface of the piston 14.

  Accordingly, when the cumulative operation amount of the internal combustion engine using the alcohol-mixed fuel (the operation duration time of the alcohol-mixed fuel, the cumulative injection amount of the alcohol-mixed fuel) exceeds a predetermined value, the ECU 53 sprays the alcohol-mixed fuel injected by the injector 43. Is set to the fuel injection timing toward the top surface 14a of the piston 14, that is, the first half of the intake stroke or the second half of the compression stroke, and the injector 43 is controlled. Then, the alcohol mixed fuel injected from the injector 43 collides with the top surface 14a of the piston 14, so that the deposit attached to the top surface 14a of the piston 14 is washed away by the high-concentration alcohol contained in the mixed fuel. Deposit accumulation in the combustion chamber 18 can be suppressed, and as a result, the occurrence of plague can be suppressed.

  Further, in the control apparatus for an internal combustion engine according to the present embodiment, the operation cumulative amount of the internal combustion engine using the alcohol mixed fuel is determined based on the operation duration time of the internal combustion engine using the alcohol mixed fuel or the cumulative injection amount of the alcohol mixed fuel injected by the injector 43. It is said. Therefore, the fuel injection timing of the mixed fuel to the top surface 14a of the piston 14 can be easily set by counting the operation continuation time and the cumulative injection amount.

  In this embodiment, the fuel mixture is stored in the fuel tank 48, and the above-described injection timing control is performed when the alcohol concentration in the mixed fuel detected by the concentration sensor is a preset alcohol concentration. In an internal combustion engine that has a fuel tank for alcohol fuel and a fuel tank for gasoline fuel separately, or has a device that can separate alcohol and gasoline from a mixed fuel of alcohol and gasoline. Even if it exists, the injection timing control mentioned above can be performed. In this case, the operation cumulative amount of the internal combustion engine with the alcohol mixed fuel may be set as the operation cumulative amount with the mixed fuel having a preset alcohol concentration or more.

  In the control apparatus for an internal combustion engine of the present embodiment, when the internal combustion engine is equal to or higher than a predetermined temperature set in advance, that is, when the engine cooling water temperature detected by the water temperature sensor 59 is equal to or higher than the predetermined temperature, the internal combustion engine using alcohol mixed fuel is used. The accumulated amount of operation is detected. Therefore, when the internal combustion engine is in a completely warmed-up state, that is, when the piston 14 is in a high temperature state, the deposit can be efficiently washed away with alcohol.

  Further, in the control device for the internal combustion engine of the present embodiment, when the cumulative operation amount of the internal combustion engine by the alcohol mixed fuel exceeds a predetermined value, the fuel injection timing by the injector 43 is set in the first half of the intake stroke. Therefore, by setting the fuel injection timing to the first half of the intake stroke, the fuel spray of the mixed fuel injected from the injector 43 can be made to collide with the top surface 14a of the piston 14 reliably, and the piston 14 The fuel adhering to the top surface 14a can be easily vaporized.

  In this case, when the total fuel injection amount exceeds a predetermined value set in advance, the fuel injection timing by the injector 43 is set to the first half of the intake stroke and the second half of the compression stroke. Therefore, when the fuel injection amount is large, the fuel spray of the mixed fuel injected from the injector 43 is surely applied to the top surface 14a of the piston 14 by injecting it in two parts, the first half of the intake stroke and the second half of the compression stroke. It can be made to collide.

  Further, in the control device for the internal combustion engine of the present embodiment, when the accumulated fuel injection amount in the execution period of the reset fuel injection timing control exceeds a predetermined value set in advance, the control is returned to the normal fuel injection timing control. Yes. Therefore, fuel injection to the top surface 14a of the piston 14 can be minimized, and oil dilution and deterioration of combustion can be suppressed.

  In the above-described embodiment, the internal combustion engine of the present invention has been described as a cylinder injection engine, but a port injection engine may be used. In this case, in accordance with the timing at which fuel is injected from the injector to the intake port, the intake valve is lifted and the intake synchronous injection that communicates with the intake port combustion chamber is executed, so that the fuel spray of the alcohol-mixed fuel injected by the injector is performed. What is necessary is just to comprise so that it may reach a combustion chamber through this communicating part from an intake port, and it may collide with the top surface of a piston.

  As described above, the control device for an internal combustion engine according to the present invention can suppress deposit accumulation in the combustion chamber, and is useful for any internal combustion engine.

1 is a schematic configuration diagram illustrating a control device for an internal combustion engine according to an embodiment of the present invention. It is a flowchart showing the deposit flush control by the control apparatus of the internal combustion engine of a present Example. It is the schematic showing the fuel injection by the injection timing in normal control. It is the schematic showing the fuel injection by the injection timing in deposit flush control.

Explanation of symbols

Reference Signs List 18 Combustion chamber 19 Intake port 20 Exhaust port 31 Intake pipe 34 Electronic throttle device 36 Exhaust pipe 43 Injector (fuel injection means)
48 fuel tank 50 spark plug 53 electronic control unit, ECU (fuel injection timing setting means, fuel injection amount setting means, fuel injection control means, alcohol fuel operation cumulative amount detection means)
59 Water temperature sensor 64 Concentration sensor

Claims (7)

Fuel injection means capable of injecting alcohol fuel into the combustion chamber or intake port of the internal combustion engine;
Fuel injection timing setting means for setting a fuel injection timing by the fuel injection means in accordance with an operating state of the internal combustion engine;
A control device for an internal combustion engine, comprising: a fuel injection control unit that controls the fuel injection unit based on a fuel injection timing set by the fuel injection timing setting unit;
An alcohol fuel operation cumulative amount detection means for detecting an operation cumulative amount of the internal combustion engine with alcohol fuel is provided;
The fuel injection timing setting means is configured to cause a spray of alcohol fuel injected by the fuel injection means to reach a piston top when the operation accumulated quantity detected by the alcohol fuel operation accumulated quantity detection means exceeds a predetermined value set in advance. Set the time to face the surface,
A control device for an internal combustion engine.   2. The control of the internal combustion engine according to claim 1, wherein the operation cumulative amount of the internal combustion engine by the alcohol fuel detected by the alcohol fuel operation cumulative amount detection means is an operation duration time of the internal combustion engine by the alcohol fuel. apparatus.   2. The cumulative operation amount of the internal combustion engine by the alcohol fuel detected by the alcohol fuel operation cumulative amount detection unit is a cumulative injection amount of the alcohol fuel injected by the fuel injection unit. Control device for internal combustion engine.   The alcohol fuel is a mixed fuel of alcohol and gasoline, and the operation cumulative amount of the internal combustion engine by the alcohol fuel detected by the alcohol fuel operation cumulative amount detection means is an operation cumulative amount by a fuel having a predetermined alcohol concentration or more. The control apparatus for an internal combustion engine according to claim 1, wherein   The alcohol fuel operation cumulative amount detection means detects the operation cumulative amount of the internal combustion engine by alcohol fuel when the internal combustion engine is at a predetermined temperature or higher. The control device for an internal combustion engine according to any one of the above.   The fuel injection timing setting means sets the fuel injection timing by the fuel injection means in the first half of the intake stroke when the operation cumulative amount detected by the alcohol fuel operation cumulative amount detection means exceeds a predetermined value. The control device for an internal combustion engine according to any one of claims 1 to 5.   Fuel injection amount setting means for setting a fuel injection amount by the fuel injection means in accordance with an operating state of the internal combustion engine is provided, and the fuel injection timing setting means is an operation cumulative amount detected by the alcohol fuel operation cumulative amount detection means. When the fuel injection amount set by the fuel injection amount setting means exceeds a predetermined value, the fuel injection timing by the fuel injection means is set to the first half of the intake stroke and the second half of the compression stroke The control apparatus for an internal combustion engine according to claim 6.

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