JP5195352B2 - Deposit remover - Google Patents

Description

  The present invention relates to a deposit removing device that removes deposits adhering to a combustion chamber of an internal combustion engine with fuel.

  2. Description of the Related Art A deposit removing device that removes deposits adhering to a combustion chamber of an in-cylinder direct injection spark ignition internal combustion engine with fuel is known (see, for example, Patent Document 1).

JP 2006-329166 A

  In the above-described conventional deposit removing apparatus, when the removing injection is continued for a predetermined time, it is switched to the normal injection uniformly. For this reason, depending on the state of vaporization of the fuel injected for removal, there has been a problem that the deposit cannot be removed sufficiently or the fuel is excessively used for removal.

  The problem to be solved by the present invention is to provide a deposit removing apparatus that can efficiently and sufficiently remove deposits.

The present invention detects the ambient temperature of an internal combustion engine, and the lower the detected ambient temperature , the lower the number of fuel injections for removing deposits (removal injection) , and further based on the rotational speed of the internal combustion engine. The said subject is solved by changing the frequency | count of removal injection .
The present invention also detects the atmospheric temperature of the internal combustion engine, reduces the number of removal injections as the detected atmospheric temperature is lower, and further reduces the rotational speed of the internal combustion engine when starting the removal injection. Thus, the above problem is solved.
Further, the present invention detects the atmospheric temperature of the internal combustion engine, reduces the number of removal injections as the detected atmospheric temperature is lower, and further removes the lower the ambient temperature when performing the removal injection in the intake stroke. The above problem is solved by retarding the timing of injection.

  According to the present invention, the atmospheric temperature of the internal combustion engine is detected to indirectly grasp the vaporization state of the fuel injected for removal, and the number of removal injections is changed accordingly. It can be removed sufficiently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system configuration diagram around an engine in an embodiment of the present invention.

  The engine 10 in the present embodiment is a so-called direct injection gasoline engine, and includes a fuel injection valve 21 and a spark plug 22 provided so as to face the combustion chamber 11 as shown in FIG. The fuel injection valve 21 directly injects fuel into the combustion chamber 11 based on a command signal from the control unit 50. The spark plug 22 ignites the air-fuel mixture filled in the combustion chamber 11 based on the ignition signal from the control unit 50. Note that a spark plug 22 having a function of detecting an ionic current in the combustion chamber 11 may be used. In this embodiment, in addition to fuel injection for normal combustion (for example, homogeneous combustion or stratified combustion), fuel injection for removing deposits adhering to the combustion chamber 11 (hereinafter referred to as removal injection) is also performed. This is performed by the fuel injection valve 21.

  Further, as shown in FIG. 1, the engine 1 includes a water temperature sensor 23, an oil temperature sensor 24, and a crank angle sensor 25. The water temperature sensor 23 (temperature detection means) detects the temperature of the cooling water in the water jacket 13 provided around the cylinder 12. The oil temperature sensor 24 detects the temperature of engine oil in the engine 10. Further, the crank angle sensor 25 detects the rotation angle of the crank. The water temperature sensor 23, the oil temperature sensor 24, and the crank angle sensor 25 are all connected to the control unit 50. The control unit 50 detects the rotational speed of the engine 10 based on the crank rotational angle provided from the crank angle sensor 25 (rotational speed detection means). In the present embodiment, detection results by the water temperature sensor 23 and the crank angle sensor 25 are used for changing the number and timing of removal injections in addition to normal applications.

  An intake air temperature sensor 31 and an air flow meter 32 are provided in the intake passage 30 communicating with the intake port 13 of the engine 10. The intake air temperature sensor 31 detects the temperature of the air taken into the intake passage 30. The air flow meter 32 detects the flow rate of the air sucked into the intake passage 30. Both the intake air temperature sensor 31 and the air flow meter 32 are connected to the control unit 50.

  The intake passage 30 is provided with a throttle valve 33 for controlling the flow rate of intake air. The opening degree of the throttle valve 33 can be adjusted by a throttle valve control device 34 having an actuator such as a DC motor. The throttle valve control device 34 is connected to the control unit 50. The control unit 50 is also connected with an accelerator operation amount sensor 51 that detects an operation amount of the accelerator pedal by the driver. When the driver operates the accelerator pedal, the control unit 50 transmits an opening signal corresponding to the operation amount to the throttle valve control device 34, and the throttle valve control device 34 opens the throttle valve 33 based on the opening signal. Adjust the degree.

  An exhaust passage 40 that communicates with the exhaust port 14 of the engine 10 is provided with an exhaust temperature sensor 41 that detects the temperature of the exhaust, and an exhaust purification catalyst 42 that purifies the exhaust. The exhaust temperature sensor 42 is connected to the control unit 50.

  The control unit 50 is composed of a microcomputer including a CPU, ROM, RAM, A / D converter, interface, and the like, to which the various sensors described above are connected. The control unit 50 controls the opening degree of the throttle valve 33 via the throttle valve control device 34 based on signals from these sensors, drives the fuel injection valve 21 to control the fuel injection amount, and performs ignition. Control is performed to set the timing and ignite the spark plug 22 at the ignition timing.

  In the present embodiment, the control unit 50 (number change means, timing change means) has a function of changing the number and timing of removal injections based on the water temperature and the engine speed, as will be described below. Control is possible.

  2 is a flowchart showing control for deposit removal in the embodiment of the present invention, FIG. 3 is a map in which water temperature is associated with the number of injections for removal, and FIG. 4 is a map in which water temperature is associated with removal injection timing. FIG. 5 is a diagram showing a map in which the engine speed and the number of removal injections are associated with each other.

  As shown in FIG. 2, in this embodiment, first, it is determined whether or not the deposit in the combustion chamber 11 needs to be removed based on the actual operation history (step S10 in FIG. 2). In general, an operation with a short travel distance, an operation with a low water temperature during operation, an operation with many low revolutions, or the like is an operation in which deposits easily adhere to the combustion chamber 11. In the present embodiment, the travel distance, the water temperature transition during operation, the rotational speed transition during operation, and the like are stored in the control unit 50 as an operation history. For example, when the above-described operation in which deposits are likely to adhere is performed a predetermined number of times, it is determined that the deposits need to be removed.

  If it is determined in step S10 that deposit removal is necessary (YES in step S10), the fuel injection mode is switched from the normal combustion (for example, homogeneous combustion or stratified combustion) mode to the deposit removal mode. On the other hand, if it is determined in step S10 that deposit removal is unnecessary (NO in step S10), the flowchart of FIG. 2 is terminated and the normal combustion mode is continued. In the deposit removal mode according to the present embodiment, the fuel is injected at a timing delayed so that the fuel adheres to the deposit in the droplet state in the intake stroke. However, the present invention is not limited to this. For example, the fuel may be attached to the deposit in a droplet state by adjusting the fuel injection pressure.

If it is determined in step S10 that deposit removal is necessary (YES in step S10), it is determined whether engine 10 is in a fully warmed state based on the coolant temperature detected by water temperature sensor 23. (Step S20 in FIG. 2). For example, in step S20, when the coolant temperature is 80 ° C. to 90 ° C., it is determined that the engine 10 is in a fully warmed state. If it is determined that engine 10 is in a fully warmed state (YES in step S20), the number of removal injections is set to M ₀ [times], and the process proceeds to step S50.

On the other hand, when it is determined in step S20 that engine 10 is not in a fully warmed state (NO in step S20), the coolant temperature is determined with reference to a water temperature-removal injection frequency map as shown in FIG. 2 is obtained (step S30 in FIG. 2). For example, in the example shown in FIG. 3, when the engine 10 is in a fully warmed state, the number of injections for removal is M ₀ [times], whereas the coolant temperature is Tw [° C.] (<80 ° C.). In this case, the number of ejections for removal is set to M ₀ −ΔM ₁ [times]. The maps shown in FIGS. 3 to 5 are stored in the control unit 50 in advance.

  Thus, in this embodiment, the number of removal injections is reduced as the coolant temperature (engine ambient temperature) is lower. When the temperature of the cooling water is low, the temperature in the combustion chamber 11 is also low, and the injected fuel is difficult to vaporize (it is easy to maintain the droplet state), so the deposit can be sufficiently removed with a small amount of fuel, Deposits can be removed efficiently.

  Note that it may be determined whether or not the engine 10 is in a cold state in step S20, and the number of removal injections may be increased when the coolant temperature is high in step S30. When the temperature of the cooling water is high, the temperature in the combustion chamber 11 is also high, and the injected fuel is easily vaporized (it is difficult to maintain the droplet state), so the deposit removing ability is reduced. On the other hand, sufficient deposit removal capability can be ensured by increasing the number of ejections for removal as the coolant temperature increases.

  Further, since the oil temperature, the intake air temperature, or the exhaust gas temperature is also correlated with the temperature in the combustion chamber 11, the oil temperature, the intake air temperature, or the exhaust gas temperature (engine ambient temperature) is used for removal instead of the water temperature. The number of injections may be increased or decreased. As described above, the oil temperature, the intake air temperature, and the exhaust gas temperature can be detected by the oil temperature sensor 24, the intake air temperature sensor 31, and the exhaust gas temperature sensor 41 (temperature detection means), respectively. Instead of this, the control unit 50 grasps the combustion state based on the ion current detected by the spark plug 22, estimates the in-cylinder temperature from this combustion state, and calculates the number of injections for removal based on this in-cylinder temperature. It may be increased or decreased. Alternatively, the in-cylinder pressure detected by the in-cylinder pressure sensor 26 may be used instead of the ionic current, or the in-cylinder temperature may be directly measured by a temperature sensor such as a thermocouple provided so as to face the combustion chamber 11. Good. Furthermore, these may be combined to increase or decrease the number of ejections for removal.

  Next, in step S40 of FIG. 2, the timing of removal injection corresponding to the coolant temperature is obtained with reference to a water temperature-removal injection timing map as shown in FIG. For example, in the example shown in FIG. 4, when the coolant temperature is Tw [° C.], the injection timing is retarded by θ [deg] in the intake stroke.

  Thus, in the present embodiment, the timing of the removal injection is retarded in the intake stroke as the coolant temperature is lower. Since the removal injection is performed at a position where the piston 15 is away from the fuel injection valve 21, the generation of smoke can be suppressed. When the coolant temperature is low, the fuel is in a droplet state even at the tip of the spray cone, so that the deposit can be sufficiently washed even if the piston 15 is separated from the fuel injection valve 21.

  Next, in step S50 of FIG. 2, it is determined whether or not the engine speed detected using the crank angle sensor 25 is higher than a target value (for example, the engine speed in the idling state). If it is determined that the actually detected engine speed is equal to or less than the target value (NO in step S50), the process proceeds to step S70 and the deposit removal mode is executed without particularly changing the number of injections for removal. .

On the other hand, when it is determined in step 50 that the engine speed is higher than the target value (YES in step S50), the engine speed is referred to by referring to the engine speed-removal injection number map as shown in FIG. The number of removal injections corresponding to the number is obtained (step S60 in FIG. 2). For example, in the example shown in FIG. 5, when the engine speed is equal to or less than the target value, the number of injections for removal is M ₀ [times], whereas the engine speed detected using the crank angle sensor 25. Is Ne [rpm] (> target value), the number of ejections for removal is set to M ₀ + ΔM ₂ [times]. If the removal injection number has already been changed to M ₀ −ΔM ₁ [times] in step S30, the removal injection number is changed from M ₀ −ΔM ₁ [times] to M _{0 in} step S60. -ΔM ₁ + ΔM ₂ [times]

  Generally, when the engine speed is high, the time during which the injected fuel is in contact with the deposit is short, so that there may be a case where a sufficient deposit removing capability cannot be ensured. On the other hand, in this embodiment, sufficient deposit removal capability can be ensured by increasing the number of removal injections as the engine speed increases.

  In step S60, the target value may be set on the high rotation side, and the number of removal injections may be decreased when the engine speed is lower than the target value. When the engine speed is low, the contact time of the injected fuel with the deposit is long. Therefore, the deposit can be sufficiently removed even with a small amount of fuel, and the deposit can be efficiently removed.

Next, in step S70 of FIG. 2, the deposit removal mode is executed. For example, if the number of injections for removal is decreased by ΔM ₁ [times] in step 30 and further increased by ΔM ₂ [times] in step S 60, the total number of intake strokes M ₀ −ΔM ₁ + ΔM ₂ [times] is taken. The removal injection is executed at. When the removal injection of M ₀ −ΔM ₁ + ΔM ₂ [times] is completed, the fuel injection mode is returned to the normal combustion (for example, homogeneous combustion or stratified combustion) mode.

  It should be noted that when the deposit removal mode is executed in step S70, the control unit 60 (rotational speed control means) controls the opening degree of the throttle valve 33 and the fuel injection amount by the fuel injection valve 21 so that the rotational speed of the engine 10 decreases. Etc. may be controlled. Thereby, the frequency | count of removal injection can be reduced actively and a deposit can be removed efficiently.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

FIG. 1 is a system configuration diagram around an engine according to an embodiment of the present invention. FIG. 2 is a flowchart showing control for deposit removal in the embodiment of the present invention. FIG. 3 is a diagram showing a map in which the water temperature is associated with the number of ejections for removal. FIG. 4 is a diagram showing a map in which the water temperature is associated with the removal injection timing. FIG. 5 is a diagram showing a map in which the engine speed and the number of injections for removal are associated with each other.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Engine 11 ... Combustion chamber 21 ... Fuel injection valve 22 ... Spark plug 23 ... Water temperature sensor 24 ... Oil temperature sensor 25 ... Crank angle sensor 30 ... Intake passage 31 ... Intake temperature sensor 40 ... Exhaust passage 41 ... Exhaust temperature sensor 50 ... control unit

Claims (5)

A deposit removing device for removing deposits adhering to a combustion chamber of a direct injection type internal combustion engine with a fuel,
Temperature detecting means for detecting the atmospheric temperature of the internal combustion engine;
Based on the detection result of the temperature detection means, the number of times changing means for changing the number of removal injections for injecting the fuel for deposit removal,
Equipped with a rotational speed detecting means for detecting a rotational speed of the internal combustion engine,
The number of times changing means decreases the number of times of the ejection for removal as the ambient temperature is lower,
The deposit removing device, wherein the number changing means changes the number of times of the ejection for removal based on a detection result by the rotation number detecting means. The number changing means, the deposit removing device according to claim 1, wherein increasing the number of the removal injection higher rotational speed detected by the rotational speed detecting means. A deposit removing device for removing deposits adhering to a combustion chamber of a direct injection type internal combustion engine with a fuel,
Temperature detecting means for detecting the atmospheric temperature of the internal combustion engine;
Based on the detection result of the temperature detection means, the number of times changing means for changing the number of removal injections for injecting the fuel for deposit removal,
Equipped with a rotational speed control means for controlling the rotational speed of the internal combustion engine,
The number of times changing means decreases the number of times of the ejection for removal as the ambient temperature is lower,
The deposit removal apparatus according to claim 1, wherein the rotation speed control means reduces the rotation speed of the internal combustion engine when starting the removal injection. A deposit removing device for removing deposits adhering to a combustion chamber of a direct injection type internal combustion engine with a fuel,
Temperature detecting means for detecting the atmospheric temperature of the internal combustion engine;
Based on the detection result of the temperature detection means, the number of times changing means for changing the number of removal injections for injecting the fuel for deposit removal,
When performing the removal injected in the intake stroke, as the ambient temperature is low, and a timing changing means for retarding the timing of the removal injection,
The deposit removing device , wherein the number changing means decreases the number of times of the ejection for removal as the ambient temperature is lower . The ambient temperature is a temperature of cooling water in the internal combustion engine, a temperature of lubricating oil in the internal combustion engine, a temperature of air sucked into the internal combustion engine, a temperature of exhaust gas exhausted from the internal combustion engine, or the internal combustion engine deposit removal device according to any one of claims 1 to 4, characterized in that it comprises at least one of the temperature in the combustion chamber.

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