JP4983747B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine, and more particularly to an in-cylinder direct injection internal combustion engine that directly injects fuel into a combustion chamber.

  2. Description of the Related Art Conventionally, an in-cylinder injection internal combustion engine in which fuel spray is directly injected into a combustion chamber in an intake stroke or a compression stroke, and a mixture of fuel spray and air is spark-ignited by an ignition plug is known (for example, Patent Documents). 1). Such an in-cylinder injection internal combustion engine is characterized in that the injected fuel spray is more likely to adhere to the cylinder inner wall than an internal combustion engine that injects fuel spray into the intake passage. For this reason, in a cold state where the engine temperature is low, vaporization of fuel spray adhering to the inner wall of the cylinder (hereinafter referred to as “adhered fuel”) is not promoted, and the adhering fuel may remain even at the ignition timing. In this case, the attached fuel may be discharged into the atmosphere without being burned, or the attached fuel may be mixed into the oil and cause oil dilution. Although it is possible to suppress oil dilution by suppressing the fuel injection timing, when the fuel injection timing is set to the initial stage of the intake stroke, fuel adheres to the piston top surface, which may cause PM generation. is there.

  By suppressing the advance amount of the fuel injection timing based on the engine water temperature, the number of PM particles mainly due to interference between the piston top surface and the spray is reduced. However, from the viewpoint of suppressing oil dilution, the injection timing is as much as possible. Want to advance. However, since it is known that the number of PM particles is generated due to interference with the intake valve when it is cold, it is also necessary to suppress interference with the intake valve.

JP 2003-20975 A

  The present invention has been made in view of the above, and an object of the present invention is to provide an internal combustion engine capable of effectively reducing the number of PM particles and oil dilution when cold.

  In order to solve the above-described problems and achieve the object, the present invention provides an internal combustion engine that directly injects fuel into a cylinder by a fuel injection device, a water temperature detecting means that detects an engine water temperature, and an oil temperature of engine oil. When the detected oil temperature detecting means and the detected engine water temperature are below a threshold, the fuel injection timing of the fuel injection device is limited, the detected engine water temperature, and the detected engine water temperature and the detected Control means for determining the advance angle limit injection timing of the fuel injection device based on the difference between the oil temperature and the oil temperature.

  According to the internal combustion engine according to the present invention, in the internal combustion engine in which fuel is directly injected into the cylinder by the fuel injection device, the water temperature detecting means for detecting the engine water temperature, the oil temperature detecting means for detecting the oil temperature of the engine oil, When the detected engine water temperature is less than or equal to a threshold value, the fuel injection timing of the fuel injection device is limited, and the detected engine water temperature and the difference between the detected engine water temperature and the detected oil temperature And an internal combustion engine capable of effectively reducing the number of PM particles and oil dilution when cold, since the control means for determining the advance limit injection timing of the fuel injection device is provided. There is an effect that it becomes possible.

  Embodiments of an internal combustion engine according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic configuration diagram showing an engine according to an embodiment of the present invention. An engine 10 as an internal combustion engine according to this embodiment is mounted on a vehicle such as a passenger car or a truck as shown in FIG. 1, and a multi-cylinder in-cylinder injection in which fuel spray is directly injected into a combustion chamber 18 by an injector 41 described later. This is a so-called four-cycle engine that performs a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while a piston 14 that is reciprocally movable in the cylinder bore 13 is reciprocated twice. is there.

  The engine 10 is a multi-cylinder in-cylinder injection type, and a cylinder head 12 is fastened on a cylinder block 11. A plurality of cylinder bores 13 formed in the cylinder block 11 can move pistons 14 up and down. It is mated. 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. An oil pan 62 for storing engine oil supplied to each part of the engine 10 is provided at the bottom of the crankcase 15. The oil pan 62 is provided with an oil temperature sensor 63 that detects the oil temperature of the engine oil, and outputs the detected oil temperature to the ECU 51. Although the oil temperature is detected by the oil temperature sensor 63 here, it may be estimated based on the engine coolant temperature, the operating state, or the like.

  The combustion chamber 18 is constituted by a wall surface of the cylinder bore 13 in the cylinder block 11, an in-cylinder ceiling as a lower surface of the cylinder head 12, and a top surface of the piston 14, and the combustion chamber 18 is an upper portion, that is, the cylinder head 12. The pent roof shape which inclines so that the center part of the in-cylinder ceiling part as a lower surface of this may become high is comprised. In the combustion chamber 18, a mixture of fuel and air can be combusted, and an intake port 19 and an exhaust port 20 are formed to face each other on an in-cylinder ceiling that is an upper portion of the combustion chamber 18. 19 and the exhaust port 20, the lower end portions of the intake valve 21 and the exhaust valve 22 are located, respectively. 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 camshaft 23 and an exhaust camshaft 24 are rotatably supported on the cylinder head 12, and the intake cam 25 and the exhaust cam 26 are in contact with the 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.

  Therefore, when the intake camshaft 23 and the exhaust camshaft 24 rotate in synchronization with the crankshaft 16, the intake cam 25 and the exhaust cam 26 move up and down the intake valve 21 and the exhaust valve 22 at a predetermined timing. 19 and the exhaust port 20 can be opened and closed so that the intake port 19 and the combustion chamber 18 can communicate with the combustion chamber 18 and the exhaust port 20, respectively. 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 10 executes the 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 are set to one. It will rotate.

  In addition, the valve mechanism of the engine 10 is a variable valve timing mechanism (VVT) 27, 28 that controls the intake valve 21 and the exhaust valve 22 at an optimal opening / closing timing according to the operating state. It has become. The intake / exhaust variable valve mechanisms 27, 28 as variable valve means are configured by providing VVT controllers 29, 30 at the shaft ends of the intake camshaft 23 and the exhaust camshaft 24. 32, the phase of the camshafts 23 and 24 with respect to the cam sprocket is changed by applying the hydraulic pressure from the VVT controllers 29 and 30 to an advance angle chamber and a retard angle chamber (not shown), so that the intake valve 21 and the exhaust valve 22 are opened and closed. Can be advanced or retarded. In this case, the intake / exhaust variable valve mechanisms 27, 28 advance or retard the opening / closing timing with the operating angles (opening periods) of the intake valve 21 and the exhaust valve 22 being constant. In addition, the intake camshaft 23 and the exhaust camshaft 24 are provided with cam position sensors 33 and 34 for detecting the rotational phase thereof.

  A surge tank 36 is connected to the intake port 19 via an intake manifold 35, and an intake pipe 37 is connected to the surge tank 36. An air cleaner 38 is attached to an air intake port of the intake pipe 37. . An electronic throttle device 40 as a load adjusting means having a throttle valve 39 is provided downstream of the air cleaner 38 in the air flow direction. Further, the cylinder head 12 is provided with an injector (fuel injection valve) 41 as fuel injection means for directly injecting fuel into the combustion chamber 18. The injector 41 is located on the intake port 19 side and is inclined at a predetermined angle in the vertical direction. The injector 41 is capable of injecting fuel toward the top surface of the piston 14 so that the fuel gets on the intake air flow generated in the combustion chamber 18. An injector 41 attached to each cylinder is connected to a delivery pipe 42, and a high pressure fuel pump (fuel pump) 44 is connected to the delivery pipe 42 via a high pressure fuel supply pipe 43. Further, the cylinder head 12 is provided with a spark plug 45 that is located above the combustion chamber 18 and ignites the air-fuel mixture.

  On the other hand, an exhaust pipe 47 is connected to the exhaust port 20 via an exhaust manifold 46. The exhaust pipe 47 is a three-way element that purifies harmful substances such as HC, CO, and NOx contained in the exhaust gas. Catalysts 48 and 49 are mounted. Further, the engine 10 is provided with a starter motor 50 that performs cranking. When an unillustrated pinion gear meshes with the ring gear when the engine is started, the rotational force is transmitted from the pinion gear to the ring gear to rotate the crankshaft 16. Can do.

  By the way, the vehicle is equipped with an electronic control unit (ECU) 51 that is configured around a microcomputer and can control each part of the engine 10, and the ECU 51 can control the injector 41, the spark plug 45, and the like. Yes. That is, an air flow sensor 52 and an intake air temperature sensor 53 are mounted on the upstream side of the air flow direction of the intake pipe 37, and an intake pressure sensor 54 is provided in the surge tank 36, and the measured intake air amount and intake air temperature are measured. The intake pressure (intake pipe negative pressure) is output to the ECU 51. In addition, a throttle position sensor 55 is attached to the electronic throttle device 40, and the current throttle opening is output to the ECU 51. Here, the ECU 51 can calculate the engine load (load factor) as the internal combustion engine load based on the detected throttle opening and intake air amount. The accelerator position sensor 56 outputs the current accelerator opening to the ECU 51. Further, a crank angle sensor 57 serving as a crank angle detecting means for detecting the crank angle of the engine 10 outputs the detected crank angle of each cylinder to the ECU 51, and the ECU 51 performs an intake stroke in each cylinder based on the detected crank angle. In addition to determining the compression stroke, the expansion stroke, and the exhaust stroke, the engine speed is calculated. Here, the engine speed corresponds to the rotational speed of the crankshaft 16 in other words. If the rotational speed of the crankshaft 16 increases, the rotational speed of the crankshaft 16, that is, the engine rotational speed of the engine 10 also increases. Get higher.

  The cylinder block 11 is provided with a water temperature sensor 58 for detecting the engine cooling water temperature, and outputs the detected engine cooling water temperature (hereinafter referred to as “engine water temperature” or “water temperature”) to the ECU 51. The delivery pipe 42 communicating with each injector 41 is provided with a fuel pressure sensor 59 that detects the fuel pressure, and outputs the detected fuel pressure to the ECU 51. On the other hand, the exhaust pipe 47 is provided with an A / F sensor 60 that detects the air-fuel ratio of the engine 10 upstream of the three-way catalyst 48 in the exhaust gas flow direction, and an oxygen sensor 61 downstream of the exhaust gas flow direction. The A / F sensor 60 detects the exhaust gas air-fuel ratio of the exhaust gas before being introduced into the three-way catalyst 48, outputs the detected air-fuel ratio to the ECU 51, and the oxygen sensor 61 is discharged from the three-way catalyst 48. Thereafter, the oxygen concentration of the exhaust gas is detected, and the detected oxygen concentration is output to the ECU 51. The air-fuel ratio (estimated air-fuel ratio) detected by the A / F sensor 60 is used for feedback control of the air-fuel ratio (theoretical air-fuel ratio) of the mixed gas composed of intake air and fuel. That is, the A / F sensor 60 detects the exhaust air-fuel ratio from the rich range to the lean range from the oxygen concentration in the exhaust gas and the unburned gas concentration, and feeds this back to the ECU 51 to correct the fuel injection amount. Thus, the combustion can be controlled to an optimum combustion state that matches the operating state.

  Therefore, the ECU 51 drives the high-pressure fuel pump 44 based on the detected fuel pressure so that the fuel pressure becomes a predetermined pressure, and also detects the detected intake air amount, intake air temperature, intake pressure, throttle opening, accelerator opening. The fuel injection amount (fuel injection period), the injection timing, the ignition timing, and the like are determined based on the engine operating state such as the engine speed and the water temperature, and the fuel injection and ignition are executed by driving the injector 41 and the spark plug 45. . Further, the ECU 51 feeds back the detected oxygen concentration of the exhaust gas to correct the fuel injection amount so that the air-fuel ratio becomes stoichiometric (theoretical air-fuel ratio).

  The ECU 51 can control the intake / exhaust variable valve mechanisms 27 and 28 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 to 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 rotational speed, so that the timing is adjusted to the inertial force of the intake air and the volume efficiency is improved.

  Furthermore, in the present embodiment, the ECU 51 executes cold PM particle number suppression control when the water temperature is equal to or lower than a threshold value in order to effectively reduce the number of PM particles and oil dilution during cold. In such cold PM particle number suppression control, the fuel injection timing of the injector 41 is limited, and the advance limit injection timing T3 is determined based on the water temperature and the difference between the water temperature and the oil temperature. Further, the retard limit injection timing T1 (first retard limit injection timing) is calculated based on the water temperature when the engine is started, and the retard limit injection timing T2 (second delay limit injection timing) is calculated based on the oil temperature. The angle limit injection timing) is calculated, and the later one is determined as the retard limit injection timing.

  In the engine 10 configured as described above, when the piston 14 descends in the cylinder bore 13, air is sucked into the combustion chamber 18 through the intake port 19 (intake stroke), and the piston 14 falls under the intake stroke. The air is compressed by moving up in the cylinder bore 13 through the dead center (compression stroke). At this time, fuel is injected into the combustion chamber 18 from the injector 41 in the intake stroke or compression stroke, and this fuel and air mix to form an air-fuel mixture. When the piston 14 approaches the top dead center of the compression stroke, the air-fuel mixture is ignited by the spark plug 45, the air-fuel mixture burns, and the piston 14 is lowered by the combustion pressure (expansion stroke). The air-fuel mixture after combustion is discharged as exhaust gas through the exhaust port 20 when the piston 14 rises again toward the top dead center of the intake stroke via the expansion stroke bottom dead center (exhaust stroke). The reciprocating motion of the piston 14 in the cylinder bore 13 is transmitted to the crankshaft 16 through the connecting rod 17, where it is converted into a rotational motion and taken out as an output. When 16 further rotates due to inertial force, the cylinder bore 13 reciprocates as the crankshaft 16 rotates. By rotating the crankshaft 16 twice, the piston 14 reciprocates the cylinder bore 13 twice, during which a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke is performed, and once in the combustion chamber 18. Explosion takes place.

  Next, with reference to FIGS. 2 to 15, the PM particle number suppression control during the cold start of the engine 10 by the ECU 51 will be described in detail. FIG. 2 is a diagram showing a behavior A (when the difference between the water temperature and the oil temperature is large) of each part temperature (intake valve temperature, oil temperature, water temperature) after the engine is started. In the figure, the horizontal axis indicates the time (minutes) after engine start, and the vertical axis indicates the temperature (° C.). Conventionally, it is known that the number of PM particles increases due to interference with the intake valve 21 during cold, but in an actual vehicle, the number of PM particles due to interference with the intake valve 21 during cold is a problem. The region I in which the intake valve temperature rapidly increases as shown in FIG.

  FIG. 3 is a diagram showing the PM particle number injection timing sensitivity in region I of FIG. FIG. 4 is a diagram showing the PM particle number injection timing sensitivity in region II of FIG. 3 and 4, the horizontal axis indicates the injection timing, and the vertical axis indicates the number of PM particles. In FIG. 3, in region I, the influence of the number of PM particles from the intake valve 21 can be reduced by calculating the retard limit of the injection timing from the interference ratio with the intake valve 21. The retard limit can be determined by the integrated injection amount (integrated injection regulation amount Qm) calculated from the water temperature at the start.

  FIG. 5 is a diagram showing a behavior B (when the difference between the water temperature and the oil temperature is small) of each part temperature (intake valve temperature, oil temperature, water temperature) after the engine is started. In the figure, the horizontal axis indicates the time (minutes) after engine start, and the vertical axis indicates the temperature (° C.).

  FIG. 6 is a diagram showing the PM particle number injection timing sensitivity at the same water temperature in region II. In the figure, the horizontal axis indicates the injection timing, and the vertical axis indicates the number of PM particles. As shown in FIG. 6, the number of PM particles due to interference with the piston 14 increases more rapidly as the water temperature is lower and the difference between the water temperature and the oil temperature is larger. For this reason, in an actual vehicle, when the fuel injection amount is greater than or equal to, the number of PM particles is predominantly discharged from the piston 14. As the water temperature is lower and the difference from the oil temperature is larger, it is possible to set the injection timing for suppressing the number of PM particles by retarding the advance limit injection timing.

  In this embodiment, as will be described later, without directly measuring each part temperature (for example, intake valve temperature or piston temperature), only by the oil temperature and the water temperature, and the integrated fuel injection amount from the engine start, The number of PM particles and oil dilution can be reduced, and smoke can also be reduced.

  FIG. 7 is a flowchart for explaining the cold control of the engine 10 by the ECU 51, and FIG. 8 is a flowchart for explaining the cold PM particle number suppression control of FIG.

  In FIG. 7, first, the ECU 51 determines whether or not the water temperature Tw ≦ the threshold value Tth (step S1). If the water temperature Tw ≦ the threshold value Tth (“Yes” in step S1), the cold PM particles are determined. While the number suppression control is executed (step S2), when the water temperature Tw ≦ the threshold value Tth is not satisfied (“No” in step S1), the normal injection timing control is executed (step S3).

  Next, the cold PM particle number suppression control in step S2 will be described with reference to FIG. In the figure, first, the ECU 51 refers to a starting water temperature / integrated injection amount prescribed value Qm map and calculates an integrated injection amount prescribed value Qm based on the engine starting water temperature (step S10).

  FIG. 9 is a diagram showing an example of the starting water temperature / integrated injection amount prescribed value Qm map. As shown in the figure, in the starting water temperature / accumulated injection amount prescribed value Qm map, the accumulated injection amount defining value Qm calculated by experiment or simulation with the engine starting water temperature as a variable is registered. The lower the water temperature at engine start, the higher the integrated injection amount is required for the intake valve temperature to rise, so the integrated injection amount prescribed value Qm is increased. The starting water temperature / integrated injection amount prescribed value Qm map is stored in the memory of the ECU 51. The ECU 51 calculates an integrated injection amount prescribed value Qm of a starting water temperature / integrated injection amount prescribed value Qm map corresponding to the detected engine starting water temperature.

  Next, the ECU 51 determines whether or not the integrated injection amount Q ≦ the calculated integrated injection amount prescribed value Qm from the engine start (step S11). If the integrated injection amount Q from the engine start is not equal to or less than the calculated integrated injection amount prescribed value Qm (step S11 “No”), the process proceeds to step S13. On the other hand, when the integrated injection amount Q from the engine start is equal to or less than the calculated integrated injection amount prescribed value Qm (“Yes” in step S11), the ECU 51 refers to the advance amount map and refers to the intake valve maximum valve lift. After calculating the advance amount from the amount (step S12), the process proceeds to step S13.

  FIG. 10 is a diagram illustrating an example of the advance amount map. As shown in the figure, the advance amount map is calculated by experiment or simulation using the integrated injection amount Q / the integrated injection amount specified value Qm (the value obtained by dividing the integrated injection amount Q by the integrated injection amount specified value Qm) as a variable. The amount of advancement from the time of the preferred maximum valve lift is registered. The smaller the integrated injection amount Q / integrated injection amount prescribed value Qm, the lower the temperature of the intake valve 21, so the advance amount from the intake valve maximum lift timing is increased. This advance amount map is stored in the memory of the ECU 51. The ECU 51 calculates the advance amount from the intake valve maximum valve lift of the advance amount map corresponding to the calculated integrated injection amount Q / integrated injection amount specified value Qm.

  In step S13, the ECU 51 calculates the retard limit injection timing T1. If the integrated injection amount Q from engine startup is equal to the calculated integrated injection amount prescribed value Qm, the retard limit injection timing T1 = the advance amount from the intake valve maximum valve lift timing calculated in step S12. When the integrated injection amount Q from engine start is not equal to the calculated integrated injection amount prescribed value Qm, the retard limit injection timing T1 is set to the initial value. In this case, the initial value of the retard limit injection timing T1 <the retard limit injection timing T2.

  Next, the ECU 51 calculates the retard limit injection timing T2 with reference to the retard limit injection timing T2 map (step S14). FIG. 11 is a diagram showing an example of the retard limit injection timing T2 map. As shown in FIG. 11, the retard limit injection timing T2 is registered in the retard limit injection timing T2 map with the oil temperature as a variable. The ECU 51 calculates the retard limit injection timing T2 of the retard limit injection timing T2 map corresponding to the current oil temperature.

  The ECU 51 calculates the advance angle limit injection time T3 with reference to the advance angle limit injection time T3 map (step S15). FIG. 12 is a diagram showing an example of the advance limit injection timing T3 map. As shown in FIG. 12, the advance angle limit injection timing T3 map shows a suitable advance angle limit injection timing T3 calculated by experiment or simulation using the water temperature and water temperature-oil temperature (difference between water temperature and oil temperature) as variables. It is registered in stages. The lower the water temperature and the higher the water temperature-oil temperature, the more retarded. The advance limit injection timing T3 map is stored in the memory of the ECU 51. The ECU 51 calculates the advance angle limit injection timing T3 of the advance angle limit injection timing T3 map corresponding to the current water temperature and water temperature-oil temperature.

  Next, the ECU 51 determines whether or not the retard limit injection timing T1 <the retard limit injection timing T2 (step S16). When the retard angle limit injection timing T1 <the retard angle limit injection timing T2 is satisfied (“Yes” in step S16), the ECU 51 sets the fuel within the range of the advance angle limit injection timing T3 <the injection timing <the retard angle limit injection timing T2. Injection is performed (step S17). On the other hand, if the retard limit injection timing T1 <the retard limit injection timing T2 is not satisfied (“No” in step S16), the ECU 51 is in the range of the advance limit injection timing T3 <injection timing <the retard limit injection timing T1. Fuel injection is performed (step S18).

  13 to 15 are diagrams for explaining the fuel injection timing according to the present embodiment. FIG. 13 is a diagram showing the PM particle number injection timing sensitivity in the region I of FIG. 2, and FIG. FIG. 15 is a diagram showing the PM particle number injection timing sensitivity at the same water temperature in region II of FIG. 2, and the arrow indicates the fuel injection timing according to the present embodiment. Is shown. As shown in FIG. 13 to FIG. 15, fuel can be injected in the region where the number of PM particles is the smallest, and PM particles caused by deterioration of oil dilution due to unnecessarily retarding the injection timing and interference with the intake valve 21. The increase in the number can be suppressed.

  As described above, according to this embodiment, when the water temperature is equal to or lower than the threshold value, the ECU 51 executes the cold PM particle number suppression control to limit the fuel injection timing, and the cold PM particle number suppression control. Then, the advance limit injection timing T1 is determined based on the water temperature and the difference between the water temperature and the oil temperature, and the retard limit injection timing T1 (first delay limit injection) is determined based on the water temperature at the start. (Time)) and the retard limit injection timing T2 (second retard limit injection timing) is calculated based on the oil temperature, and the later one is determined as the retard limit injection timing. It is possible to effectively reduce the number of PM particles and oil dilution when cold.

  As described above, the internal combustion engine according to the present invention is suitable for use in various in-cylinder direct injection internal combustion engines that inject fuel directly into a combustion chamber.

It is a schematic block diagram showing the engine which concerns on the Example of this invention. It is a figure which shows the behavior A (when the difference of water temperature and oil temperature is large) of each part temperature (intake valve temperature, oil temperature, water temperature) after engine starting. It is a figure which shows the PM particle number injection timing sensitivity in the area | region I of FIG. It is a figure which shows the PM particle number injection timing sensitivity in the area | region II of FIG. It is a figure which shows the behavior B (when the difference of water temperature and oil temperature is small) of each part temperature (intake valve temperature, oil temperature, water temperature) after engine starting. It is a figure which shows the PM particle number injection timing sensitivity in the same water temperature in the area | region II. 4 is a flowchart for illustrating control by ECU 51 when the engine 10 is cold. It is a flowchart for demonstrating cold PM particle number suppression control of FIG. It is a figure which shows an example of the water temperature at the time of starting, and integrated injection amount regulation value Qm map. It is a figure which shows an example of an advance amount map. It is a figure which shows an example of the retard limit injection timing T2 map. It is a figure which shows an example of an advance angle limit injection time T3 map. It is a figure for demonstrating the fuel-injection time by a present Example. It is a figure for demonstrating the fuel-injection time by a present Example. It is a figure for demonstrating the fuel-injection time by a present Example.

Explanation of symbols

10 Engine (Internal combustion engine)
13 Cylinder bore 14 Piston 18 Combustion chamber 21 Intake valve 22 Exhaust valve 41 Injector 51 ECU (control means)
58 Water temperature sensor (Water temperature detection means)
62 Oil temperature sensor (oil temperature detection means)

Claims (3)

In an internal combustion engine in which fuel is directly injected into a cylinder by a fuel injection device,
Water temperature detecting means for detecting engine water temperature;
Oil temperature detection means for detecting the oil temperature of the engine oil;
When the detected engine water temperature is less than or equal to a threshold value, the fuel injection timing of the fuel injection device is limited, and the detected engine water temperature and the difference between the detected engine water temperature and the detected oil temperature Based on the control means for determining the advance limit injection timing of the fuel injection device,
An internal combustion engine comprising:   The control means delays the advance limit injection timing as the detected engine water temperature is low and the difference between the detected engine water temperature and the detected oil temperature is large. The internal combustion engine according to claim 1.   The control means calculates a first retard limit injection timing of the fuel injection device based on an engine water temperature when the internal combustion engine is started, and a second delay time of the fuel injection device based on the detected oil temperature. 3. The internal combustion engine according to claim 1, wherein the retard limit injection timing is calculated, and the later one is determined as the retard limit injection timing of the fuel injection device. 4.

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