JP2017106360A - Control device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control a combustion state in a cylinder to a satisfactory combustion state by properly recognizing the combustion state.SOLUTION: A control device of an engine includes: a crank shaft C rotating accompanied with output of an engine E; angular velocity detection means 21 calculating an angular velocity of the rotation of the crank shaft C on the basis of a sectioning angle set to a crank angle of the crank shaft C; angular acceleration calculation means 22 for calculating angular acceleration from the angular velocity corresponding to two sectioning angles obtained along time series by the angular velocity detection means 21; and combustion control means 24 for controlling combustion in a cylinder on the basis of the change of the angular acceleration calculated by the angular acceleration calculation means 22. The angular velocity detection means 21 calculates the angular velocity on the basis of each of a plurality of sectioning angle patterns different in boundary positions of the adjacent sectioning angles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an engine control device having a function of estimating a combustion state in a cylinder and controlling the combustion state.

  In general, it is said that misfire in a diesel engine is likely to occur when the exhaust gas recirculation gas is excessive, the oxygen amount is insufficient due to insufficient supercharging pressure, or the intake air temperature or water temperature is decreased.

  The fuel injection timing in a diesel engine is usually determined from a required torque that is determined by two factors, the engine speed and the accelerator opening. For this reason, in order to prevent misfire, in addition to the above control, it is necessary to correct the fuel injection timing in accordance with the in-cylinder state such as an insufficient oxygen amount or a temperature drop.

  However, from the viewpoint of environmental protection such as exhaust gas regulations, the filling ratio of the exhaust recirculation gas tends to increase year by year. For this reason, the setting range of the fuel injection timing capable of proper operation is limited to a narrow crank angle range, and the degree of freedom of control is becoming narrower. In addition, a slight change in the driving situation is likely to lead to misfire. It is desirable to avoid combustion fluctuations due to misfire as much as possible, because it leads to deterioration of drivability accompanying a decrease in torque and increased emission of unburned hydrocarbons. The combustion fluctuation means a change or fluctuation in the combustion state for each combustion cycle of each cylinder.

  In Patent Literature 1, a plurality of division angles (regions) are set for the crank angle of the crankshaft, and the plurality of division angles are divided into a high rotation region division angle and a low rotation region division angle according to the engine speed. There is described a technique for switching and detecting combustion fluctuations such as misfire in each of a high rotation range and a low rotation range based on the angular acceleration of the crankshaft at a corresponding division angle.

Japanese Patent Laid-Open No. 9-166041

  In the engine control method described in Patent Document 1, misfire determination is performed when the angular acceleration of the crankshaft falls below a predetermined misfire determination threshold. Here, the angular acceleration of the crankshaft can be calculated from the change in the angular velocity of the crankshaft. For example, the angular velocity is calculated based on the time required to rotate one section of the crankshaft and the crank angle that has progressed during the required time, and the angular acceleration is calculated from the two angular velocities obtained along the time series. can do.

  However, with this method, there is a problem that the change in the angular velocity that occurs near the boundary between the crank angle division angles is difficult to be reflected in the calculated angular acceleration. That is, when the angular velocity of the crankshaft changes near the boundary between the crank angle divisions, the change may be distributed to both divisions across the boundary. Therefore, the engine control method disclosed in Patent Document 1 has a problem that it is desired to more accurately grasp the variation in combustion fluctuation for each cylinder.

  Therefore, an object of the present invention is to more accurately grasp the combustion state in the cylinder and control it to a good combustion state.

  In order to solve the above problems, the present invention calculates a crankshaft that rotates in accordance with the output of an engine and an angular velocity of rotation of the crankshaft based on a division angle set to the crank angle of the crankshaft. Angular velocity detection means, angular acceleration calculation means for calculating angular acceleration from angular velocities corresponding to two division angles obtained along the time series by the angular velocity detection means, and changes in angular acceleration calculated by the angular acceleration calculation means A combustion control means for controlling combustion in the cylinder based on the angular velocity detection means, wherein the angular velocity detection means has a plurality of types of partition angle patterns having different boundary positions between adjacent partition angles, and the plurality of types of partition angle patterns. The engine control device that calculates the angular velocity based on each of the above was adopted.

  Here, the angular acceleration calculating means calculates angular acceleration based on a plurality of angular velocities obtained based on a plurality of types of partition angle patterns, and the combustion control means is a fuel injection employed for controlling combustion. A correction amount for the set value of the timing or fuel injection amount is calculated based on the angular acceleration due to the angular velocity based on different division angle patterns, and the correction amount having the largest absolute value is compared by comparing the calculated correction amounts. The structure which applies can be employ | adopted.

  At this time, the angular velocity detecting means sequentially calculates a plurality of angular velocities obtained based on a plurality of types of dividing angle patterns for each cycle of the crankshaft, and the angular acceleration calculating means calculates different dividing angle patterns calculated in order. It is possible to employ a configuration in which the angular acceleration is calculated based on the angular velocity based on each.

  Further, the angular velocity detecting means calculates a plurality of angular velocities obtained based on a plurality of types of dividing angle patterns simultaneously during one crankshaft cycle, and the angular acceleration calculating means calculates different dividing angle patterns calculated simultaneously. A configuration in which the angular acceleration is calculated based on the angular velocity based on each can be employed.

  Here, when the engine is a compression self-ignition engine, when the combustion control unit can switch between premixed combustion and diffusion combustion, a plurality of division angle patterns obtained based on a plurality of division angle patterns are obtained. It is possible to adopt a configuration in which the correction amount based on the angular velocity and the angular acceleration is applied only during diffusion combustion.

  The combustion control means calculates a predetermined time when the heat generation amount in the cylinder is a predetermined ratio with respect to the total heat generation amount of one cycle based on the change in angular acceleration calculated by the angular acceleration calculation means, A configuration in which the correction amount is calculated by comparing the predetermined time with a predetermined heat generation time reference value can be employed.

  Here, it is possible to adopt a configuration in which the predetermined time is a heat generation center of gravity, and the heat generation time reference value is a heat generation center of gravity reference value.

  Alternatively, the combustion control unit calculates an ignition timing based on a change in angular acceleration calculated by the angular acceleration calculation unit, and compares the ignition timing with a predetermined ignition timing reference value to calculate the correction amount. The structure which calculates can be employ | adopted.

  Further, the angular acceleration calculating means selects one angular velocity from a plurality of angular velocities obtained based on a plurality of types of division angle patterns, calculates the angular acceleration, and the combustion control means is employed for controlling combustion. It is possible to employ a configuration in which a correction amount for the set value of the fuel injection timing or the fuel injection amount that has been calculated is applied based on the angular acceleration based on the selected angular velocity.

  According to the present invention, the angular velocity of rotation of the crankshaft is calculated based on a plurality of types of division angle patterns set to the crank angle, and based on the angular acceleration calculated by each angular velocity calculated by different division angle patterns. Thus, the combustion state is controlled, so that the combustion state in the cylinder can be grasped more accurately and controlled to a good combustion state.

It is a schematic diagram which shows the structure of the control apparatus of the engine of this invention. It is a schematic diagram which shows the structure of the rotation sensor which detects rotation of the crankshaft of an engine. It is a schematic diagram which shows the example of the pulse for detecting rotation of a crankshaft. It is a schematic diagram which shows the example of a setting of the crank angle for calculating the rotation angular velocity and rotation angle acceleration of a crankshaft. It is a schematic diagram which shows another example of the setting of the crank angle for calculating the rotational angular velocity and rotational angular acceleration of a crankshaft. It is a graph which shows the relationship between the variation | change_quantity of the rotational angular acceleration of a crankshaft, and a heat generation gravity center. It is a flowchart of control by the engine control apparatus of one Embodiment of this invention. It is a graph which shows the relationship between a cylinder pressure and a crank angle, and the relationship between a heat release rate and a crank angle. It is a graph which shows the relationship between the time which a crankshaft rotates 30 degree | times, and a crank angle, and the relationship between the rotation angle acceleration of a crankshaft, and a crank angle. It is a graph which shows the relationship between the change of the rotational angular acceleration of a crankshaft, and a heat generation gravity center. (A) to (c) are graphs showing the relationship between generated torque and heat generating center of gravity, noise and heat generating center of gravity, crankshaft rotation angular acceleration change and heat generating center of gravity, respectively (c) to (f) FIG. 5 is a graph showing the relationship between generated torque and heat generation center of gravity, noise and heat generation center of gravity, crankshaft rotation angular acceleration change, and heat generation center of gravity.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram conceptually showing the control device for the engine of this embodiment.

  The engine E of this embodiment is an automobile diesel engine. As shown in FIG. 1, the configuration of the engine E includes a piston P connected to the crankshaft C via a connecting rod, an intake port for sending intake air into a cylinder containing the piston P, and an intake passage 1 leading to the intake port. The exhaust passage 2 drawn out from the exhaust port, the fuel injection device D and the like are provided. The intake port and the exhaust port are opened and closed by valves 1a and 2a, respectively.

  In this embodiment, a multi-cylinder engine having a plurality of cylinders is assumed, and FIG. 1 shows one of them, but the present invention can be applied regardless of the number of cylinders.

  The intake passage 1 has a high-pressure throttle valve 5 that adjusts the flow area of the intake port upstream from the intake port, an intake air cooling device (intercooler) 6 that cools the intake air flowing through the intake passage 1, and a turbocharger. In the intake passage 11 further upstream of the compressor 17, a low-pressure throttle valve 15, an air cleaner 16, and the like for adjusting the flow passage area are provided.

  In the exhaust passage 2, a turbocharger turbine 7, an exhaust purification unit 8 including a catalyst for removing unburned hydrocarbon (HC) and the like in the exhaust, and the like, a muffler (muffler) from the exhaust port toward the downstream side 12 is provided.

  A midway portion between the turbine 7 and the exhaust port in the exhaust passage 2 and a midway portion between the intake port and the high pressure throttle valve 5 in the intake passage 1 are communicated with each other by a high pressure exhaust gas recirculation passage 3 constituting a high pressure exhaust gas recirculation device. Yes. A part of the exhaust gas discharged from the engine E returns to the intake passage 1 as a recirculation gas via the high-pressure exhaust recirculation passage 3. A high-pressure exhaust gas recirculation valve 4 is provided in the high-pressure exhaust gas recirculation passage 3. The recirculated gas merges with the intake air in the intake passage 1 in accordance with the pressure state in the intake passage 1 that accompanies the opening and closing of the high pressure exhaust recirculation valve 4 and the opening and closing of the high pressure throttle valve 5.

  Further, midway portions of the exhaust purification unit 8 and the silencer 12 in the exhaust passage 2 and midway portions of the compressor 17 and the low pressure throttle valve 15 in the intake passage 11 are low pressure exhaust gas recirculation passages constituting a low pressure exhaust gas recirculation device. 13 communicates. A part of the exhaust gas discharged from the engine E returns to the upstream side of the compressor 17 of the turbocharger in the intake passage 11 as the reflux gas via the low-pressure exhaust recirculation passage 13. The low pressure exhaust gas recirculation passage 13 is provided with a low pressure exhaust gas recirculation valve 14. The recirculated gas merges with the intake air in the intake passage 11 according to the pressure state in the intake passage 11 that is associated with the opening and closing of the low pressure exhaust recirculation valve 14 and the opening and closing of the low pressure throttle valve 15. Reference numeral 10 in the figure is a recirculation gas cooler that cools the recirculation gas in the low-pressure exhaust recirculation passage 13.

  A vehicle equipped with the engine E includes an electronic control unit 20 for controlling the engine.

  The electronic control unit 20 includes fuel injection execution means 25 that executes fuel injection by the fuel injection device D. The fuel injection execution means 25 controls the fuel injection timing and the fuel injection amount in accordance with the operating conditions. Further, the electronic control unit 20 includes control means 26 for controlling the supercharging pressure, controlling the opening degree of the high-pressure throttle valve 5 and the low-pressure throttle valve 15, and other commands necessary for controlling the engine.

  Further, the electronic control unit 20 detects an angular velocity of the crankshaft C driven in accordance with the output of the engine E, and calculates an angular acceleration based on the angular velocity detected by the angular velocity detector 21. Acceleration calculation means 22.

  The angular velocity detection means 21 calculates the angular velocity of rotation of the crankshaft C based on the division angle set to the crank angle of the crankshaft C. Specifically, the angular velocity detection means 21 can calculate the angular velocity based on the time required for the rotation of the set dividing angle and the crank angle that has progressed during the required time. The angular speed is calculated by dividing the advanced crank angle by the time required for the advance.

  Further, the angular acceleration calculation means 22 calculates angular acceleration from the angular velocities corresponding to the two division angles obtained along the time series by the angular velocity detection means 21. Specifically, the angular acceleration calculation means 22 calculates the angular acceleration based on the difference between the angular velocities corresponding to two adjacent division angles along the time series and the time required to change by the difference. be able to. The angular acceleration is calculated by dividing the change amount of the angular velocity by the time required for the change.

  In this embodiment, the angular velocity detection means 21 calculates the angular velocity of rotation of the crankshaft C for every 30 degrees division angle (region) set to the crank angle of the crankshaft C, as shown in FIG. It has become. As shown in the drawing, a total of twelve regions 1, 2, 3,... Are provided along the direction of 360 degrees around the crankshaft C as shown in the drawing.

  The angle of one division angle is not limited to 30 degrees, and may be, for example, 20 degrees, 15 degrees, or the like. It is desirable that adjacent partition angles are not overlapped with each other and are continuous without being separated from each other.

  Further, the angular velocity detecting means 21 has a plurality of types of partition angle patterns in which the boundary positions between adjacent partition angles are different.

  In this embodiment, the angular velocity detection means 21 includes a dividing angle pattern shown in FIG. 5 in addition to FIG. Hereinafter, the partition angle pattern illustrated in FIG. 4 is referred to as a first partition angle pattern, and the partition angle pattern illustrated in FIG. 5 is referred to as a second partition angle pattern.

  The second division angle pattern shown in FIG. 5 is different from the first division angle pattern in the boundary position between adjacent division angles.

  The second division angle pattern has a division angle of every 30 degrees as in the first division angle pattern. A total of 12 regions 1 ', 2', 3 ',... Are provided in the direction of 360 degrees around the axis of the crankshaft C.

  Also in the second division angle pattern, the angle of one division angle is not limited to 30 degrees, and may be, for example, 20 degrees, 15 degrees, etc., but the angle of one division angle of the first division angle pattern And the angle of one division angle of the second division angle pattern is desirably the same angle. Also in the second partition angle pattern, it is desirable that adjacent partition angles do not overlap with each other and are continuous without being separated from each other.

  The angular velocity detection means 21 calculates the angular velocity of rotation of the crankshaft C for each 30-degree division angle using each of the first division angle pattern and the second division angle pattern.

  Here, for example, when comparing the areas including the compression top dead center, the area 4 ′ that is one division angle of the second division angle pattern is the area 4 that is one division angle of the first division angle pattern. The position is advanced by 15 degrees. The advance amount is not limited to 15 degrees, and may be, for example, 5 degrees, 10 degrees, 20 degrees, or the like.

  The combustion control means 24 controls the combustion in the cylinder based on the change in angular acceleration calculated by the angular acceleration calculation means 22.

  This combustion control is calculated by calculating the correction amount for the set value of the fuel injection timing or fuel injection amount used to control the combustion based on the angular acceleration based on the angular velocity based on different partition angle patterns. The plurality of correction amounts are compared with each other, and the correction amount having the largest absolute value is applied to the current set value.

  In this embodiment, the combustion state calculation means 23 provided in the electronic control unit 20 changes the heat generation amount in the cylinder to the total heat generation amount in one cycle based on the change in angular acceleration calculated by the angular acceleration calculation means 22. On the other hand, a predetermined time having a predetermined ratio is calculated, and a correction amount is calculated by comparing the predetermined time with a predetermined heat generation time reference value.

Here, the predetermined timing is a heat generating centroid, heat generated timing reference value employs the heat generation centroid reference value G _0. That is, in this embodiment, as the predetermined time calculated by the combustion state calculation means 23, a heat generation center of gravity G that is a time when the heat generation amount becomes 50% of the total heat generation amount of one cycle is adopted. Yes. Hereinafter, in this embodiment, the predetermined time is set as the heat generation gravity center G.

Combustion control means 24, by comparing the heat generation center of gravity G calculated by the combustion state calculation unit 23, the heat generated centroid reference value G _0, which is predetermined as a heat generating timing reference value, to control the combustion in the cylinder . The combustion control means 24 instructs the fuel injection execution means 25 to correct the necessary fuel injection timing. Further, the combustion control means 24 can also instruct the fuel injection execution means 25 to correct the fuel injection amount in the state where the fuel injection timing correction is instructed.

  The angular velocity detection means 21 acquires information from the crank angle sensor 30 and the cylinder discrimination sensor 33 provided in the engine E as shown in FIGS.

  The crank angle sensor 30 includes a rotating member 31 that rotates integrally with the crankshaft C of the engine, and a plurality of vanes 31 a that are formed on the periphery of the rotating member 31 and project outward in the radial direction. The vanes 31a are provided at regular intervals along the circumferential direction of the rotating member 31, and the adjacent vanes 31a all have circumferential lengths corresponding to the constant rotation angle of the crankshaft C. A detection unit 32 provided to face the vane 31a optically or electromagnetically detects the passage of the vane 31a accompanying the rotation of the rotating member 31, and outputs a pulse based on the detection. (See (b), (d) and (e) in FIG. 3).

  The cylinder discrimination sensor 33 is provided on the camshaft in the cylinder head. While the crankshaft C rotates twice around the axis and the camshaft rotates once around the axis, a predetermined pulse is output every time the camshaft takes a specific rotational position corresponding to one cylinder. (See (c), (d), and (e) in FIG. 3).

  The detection of the angular acceleration will be described. During the operation of the engine E, the electronic control unit 20 acquires the pulse output from the crank angle sensor 30 and the detection signal of the cylinder discrimination sensor 33, and repeats the calculation continuously. To do.

  The electronic control unit 20 determines what number the pulse output from the crank angle sensor 30 is after the specific pulse output from the cylinder determination sensor 33. Thus, the pulse from the input crank angle sensor 30 can be used to calculate the stroke of intake, compression, expansion, and exhaust of each cylinder, that is, the heat generation gravity center G of the numbered cylinder. Identify whether it is information. Specifically, the number of the cylinder that is executing the expansion stroke (for example, around the top dead center of the expansion stroke) at the time of the pulse acquisition is identified.

  The electronic control unit 20 responds to a pulse from the crank angle sensor 30 with a timer for the identified cylinder (or a group of cylinders including the identified cylinder and proceeding in the same process as the cylinder). Start.

  When a predetermined number of pulses are acquired from the crank angle sensor 30 after the timer is started, the electronic control unit 20 stops the timer and acquires the elapsed time after the timer is started. This time measurement result is a time required for the crankshaft C to rotate by a predetermined rotation angle in a predetermined region around the compression top dead center of the piston P of the identified cylinder. Hereinafter, it is referred to as “predetermined angle elapsed time”.

  In this embodiment, as shown in FIG. 3 (b), the vane 31a is set to 60 teeth every 6 degrees (however, since the identification missing tooth 4 is included, 56 pulses), this predetermined angle elapsed time is The angle corresponding to the passage of the five vanes 31a, that is, the time required for the rotation angle of the crankshaft C to be 30 degrees as shown in FIG. This angle may be other than 30 degrees, for example, 20 degrees, 15 degrees, or the like.

  The angular velocity detection means 21 calculates an average angular velocity during the passage through the predetermined rotation angle (30 degrees) based on the predetermined angle elapsed time.

The calculation formula is, for example,
(Expression 1) Angular velocity ω _n = (π / 6) ÷ (T _{ca (n)} )
It becomes.
Here, T _{ca (n)} is the nth time from the start of the timer among the predetermined angle elapsed time for each predetermined rotation angle (30 degrees = π / 6 rad) acquired corresponding to the identified cylinder. Indicates that

  The angular acceleration calculation means 22 calculates the angular acceleration based on these angular velocity information. The angular acceleration is calculated based on two angular velocities obtained along the time series. In this embodiment, two angular velocities adjacent to each other along the time series are used.

The calculation formula is, for example,
(Expression 2) Angular acceleration α _{n−1 to n}
= D ² θ / dt ²
= 10 ¹² ×
[{(Π / 6) ÷ (T _{ca (n)} )} − {(π / 6) ÷ (T _{ca (n−1)} )}]
/ {( _{Tca (n-1)} ) + ( _{Tca (n)} )} / 2
It becomes.
This is the angular acceleration α _n calculated based on the n−1th predetermined angle elapsed time T _{ca (n−1)} acquired from the timer start and the nth acquired predetermined angle elapsed time T _{ca (n). -1} to _n are shown. That is, α _{n−1 to n} are average angular accelerations from the measurement start end to the measurement end in a range of an angle (60 degrees) twice a predetermined rotation angle (30 degrees = π / 6 rad).

  For example, in the first dividing angle pattern of FIG. 4, the predetermined angle elapsed time, angular velocity, and angular acceleration every 30 degrees are calculated in a period in which the piston P of the identified cylinder is in the region of 180 degrees before and after the compression top dead center. Calculate.

Here, the region of the crank angle of 180 degrees from the timer start to the timer stop is divided into six regions every 30 degrees. The angular velocity ω ₄ based on the time T ₄ (T _{ca (4)} ) passing through the region 4 (18 degrees before the top dead center and 12 degrees after the top dead center) that is the fourth region from the timer start, and the region 5 (the top The angular acceleration calculated by the angular velocity ω ₅ based on the time T ₅ (T _{ca (5)} ) passing through 12 degrees after dead center to 42 degrees after top dead center is α ₄₅ (α _4-5 ), and region 5 and the angular velocity omega _5, the angular acceleration is calculated by the angular velocity omega ₆ based on the time _T 6 passing through (72 degrees after top dead center to 42 ° after top dead _{center) (T ca (6))} region 6 alpha ₅₆ (Α _5-6 ). α ₄₅ is an average angular acceleration from the measurement start end s to the measurement end u in the corresponding 60-degree range. α ₅₆ is an average angular acceleration from the measurement start end t to the measurement end v in the corresponding range of 60 degrees.

  Based on the angular acceleration information calculated by the angular acceleration calculating means 22, the combustion state calculating means 23 calculates the heat generation gravity center G of the corresponding cylinder based on the change in the angular acceleration.

  The heat generation center of gravity G means that when the generated energy (heat) from the start of combustion to the end of combustion in one cycle of one cylinder is 100, the integrated value of the combustion energy (heat) generated from the start of combustion is half. It is the time when it reached 50. That is, the position of the crank angle θ at which the heat generation amount reaches 50% of the total heat generation amount in one cycle of one cylinder is set as the heat generation gravity center G.

The heat generation amount can also be obtained by integrating the heat generation rate (heat generation amount per unit crank angle), but in the present invention, instead of directly calculating the heat generation amount, the heat generation gravity center G, Paying attention to the fact that there is a linear correlation between the difference Δα between the two angular accelerations α _{n− 1 to n} and α _{n to n + 1} obtained along the time series of rotation of the crankshaft C, The heat generation center of gravity G is obtained based on the change in acceleration and the torque value of the engine E. In the present embodiment, this is calculated by paying attention to the heat generation center of gravity G. However, for example, a correlation between Δα and the time when it reaches a range of 30 to 80% of the total heat generation amount is acquired in advance. The present invention can also be implemented by calculating the time to reach the range based on the change in angular acceleration and the torque value of the engine E.

For example, FIG. 6 is a chart showing the correlation for calculating the heat generation gravity center G. Here, the horizontal axis represents the crank angle θ (deg. CA) of the heat generation center of gravity G, and the vertical axis represents the angular acceleration change, that is, the difference Δα between the values of the two angular accelerations α _{n− 1 to n} and α _{n to n + 1.} Yes. Here, n = 5, and Δα = α _5-6 -α _4-5 is expressed as Δα = α ₅₆ -α ₄₅ .

For example, in the case where the generated torque of the engine is 120 Nm, in FIG. 6, the relationship between the crank angle θ of the heat generation center of gravity G and the angular acceleration change Δα = α ₅₆ −α ₄₅ is represented by Δ mark: a located at the uppermost position. The distribution is as shown. Such information can be acquired in advance by an experiment using the same type of master engine or the like. Based on the distribution of these pieces of information, an approximate expression H ₁₂₀ by the least square method or the like is obtained. The crank angle θ of the heat generation gravity center G can be obtained if the change in angular acceleration Δα = α ₅₆ −α ₄₅ is found from the approximate expression H ₁₂₀ under the condition that the generated torque is ₁₂₀ Nm.

For example, when the generated torque of the engine is 80 Nm, in FIG. 6, the relationship between the crank angle θ of the heat generation center of gravity G and the change in angular acceleration Δα = α ₅₆ −α ₄₅ is indicated in the center by □: b It becomes distribution shown by. When the generated torque of the engine is 20 Nm, the relationship between the crank angle θ of the heat generation center of gravity G and the angular acceleration change Δα = α ₅₆ −α ₄₅ has a distribution indicated by a circle mark “c” positioned at the lowermost position.
If a similar approximate expression is obtained even under other torque conditions, for example, 100 Nm, 60 Nm, 40 Nm, etc., if the angular acceleration change Δα = α ₅₆ −α ₄₅ is found under the torque conditions, The crank angle θ of the generated center of gravity G can be obtained. The pitch of the torque for acquiring data can be freely set every 10 Nm, every 20 Nm, or the like.

However, FIG. 6 shows the _relationship between the crank angle θ of the heat generation center of gravity G under the condition of the engine speed of 1500 revolutions / minute (min ⁻¹ ) and the angular acceleration change Δα = α _{n to n + 1} −α _{n− 1 to n} . It shows the relationship. At other engine speeds, for example, 2000 rpm / min, 2500 rpm / min, 3500 rpm / min, and the like, if a similar map diagram is obtained, the torque condition and angular acceleration change Δα = α ₅₆ -α ₄₅ If it becomes clear, the crank angle θ of the heat generation center of gravity G can be obtained. The pitch of the engine speed at which data is acquired can be freely set at every 500 revolutions / minute, every 100 revolutions / minute, or the like.

Here, the time series of the values of the two angular accelerations α _{n− 1 to n} and α _{n to n + 1} (in the embodiment, α ₄₅ and α ₅₆ ) serving as a reference for calculating the heat generation center of gravity G is the previous one. It is desirable that a certain angular acceleration value (α _{45 in the} embodiment) is detected in a range of a crank angle straddling the top dead center in the early stage of the expansion stroke.

That is, the change in angular acceleration Δα = α _{n to n + 1} −α _{n− 1 to n serving as} a reference for calculating the heat generation gravity center G is within a certain time before and after the passage of the top dead center in the initial stage of the expansion stroke. This is because the numerical value at is considered to have the strongest correlation with the position of the heat generation center of gravity G.

This, for example, the angular velocity omega _n initiated acquisition after completely through the top dead center in the expansion stroke initial, subsequent angular velocity omega _{n + 1,} the angular acceleration based on only the information of ω _{n + 2} ··· α n~ _{This is because if n + 1} ... is calculated, the heat generation center of gravity G is already calculated based only on the information after the combustion is partially started. Further, for example, the angular acceleration α _n− is based on only the information of the angular velocity ω _n that has been acquired before completely passing through the top dead center and the angular velocities ω _n−1 , ω _{n−2. This} is because calculating 1 to _n ... Includes a lot of information on a region where combustion is not started.

Also, when calculating the reference become angular acceleration change _{Δα = α n~n + 1 -α n} -1~n for calculating a heat generation center of gravity G, time series of the angular acceleration alpha _{n-1 to n} in front The values are the angular velocity ω _n−1 detected in the crank angle range over the top dead center in the initial stage of the expansion stroke, and the angular velocity ω detected in the crank angle range following the crank angle range over the top dead center. More preferably, it is calculated based on _n .

In this way, information on the heat generation center of gravity G1 is obtained as the value of the heat generation center of gravity G based on the angular velocity and angular acceleration obtained based on the first division angle pattern. Based on the information of the heat generating centroid G1, combustion control means 24 of the electronic control unit 20 is calculated by comparison with heat generation centroid reference value G ₀ which is determined in advance, fuel injection timing, the correction amount of the fuel injection amount To do.

Next, information on the heat generation center of gravity G2 is obtained as a value of the heat generation center of gravity G based on the angular velocity and angular acceleration obtained based on the second division angle pattern by the same process. Based on the information of the heat generating centroid G2, combustion control means 24 of the electronic control unit 20 is calculated by comparison with heat generation centroid reference value G ₀ which is determined in advance, fuel injection timing, the correction amount of the fuel injection amount To do.

  In this embodiment, the angular velocity detection means 21 alternately calculates a plurality of angular velocities obtained based on different division angle patterns by changing the division angle pattern for each cycle of the crankshaft. The angular acceleration calculation means 22 calculates the angular acceleration based on the angular velocities based on different division angle patterns calculated alternately.

The combustion control means 24 converts the correction amount for the set value of the fuel injection timing or the fuel injection amount employed for controlling the combustion into a correction amount based on the first partition angle pattern and a second partition angle pattern. The correction amount based on the comparison is compared, and the correction amount having the largest absolute value is applied to the set value. The correction amount corresponds to the fuel injection timing and fuel injection amount set values already set for the engine E in operation, and the heat generation center of gravity G (G1 or G2) is used as the heat generation center of gravity reference value G _0. It is applied to correct the fuel injection timing and the fuel injection amount for

  At this time, the combustion control means 24 instructs the fuel injection execution means 25 to correct the necessary fuel injection timing. Further, the combustion control means 24 compares the generated torque with the target torque in a state where the correction of the fuel injection timing is commanded. If the generated torque is different from the target torque, the fuel injection is performed so that the generated torque matches the target torque. It is also possible to instruct the execution means 25 to correct the required fuel injection amount.

Here, the heat generation center-of-gravity reference value G ₀ is the heat generation determined to be appropriate without causing misfire or the like under various operating conditions in addition to the torque condition, the value of change in angular acceleration, and the value of engine speed. This is the position of the center of gravity G. Information of these heat-release center of gravity reference value G ₀ is the experiment using the master engine or the like of the same type, can be obtained in advance (for example, see FIG. 10 described later). The same applies to the target torque information.

Combustion control means 24, the heat generation centroid G calculated by the combustion state calculation unit 23 is controlled to approach the heat generating centroid reference value G _0. In this embodiment, the control of the combustion in the cylinder by the combustion control means 24 is performed by adjusting the fuel injection timing or the fuel injection amount.

Specifically, when the heat generating center of gravity G is in the late than the heat generating centroid reference value G ₀ is the heat generation center of gravity G as close to the heat generating centroid reference value G _0, current fuel injection timing More advanced. Conversely, if the heat generated center of gravity G is in the early than the heat generating centroid reference value G ₀ is the heat generation center of gravity G as close to the heat generating centroid reference value G _0, than the current fuel injection timing Retard. Normally, the fuel injection amount is proportional to the fuel injection duration.

  The control of the combustion state in the cylinder by the combustion control means 24 can be performed separately for each identified cylinder, or a group of cylinders including the identified cylinder and proceeding in the same process as the cylinder. It is possible to perform the same control on the group all at once.

The correction of the fuel injection by this method, carried out respectively for all of the cylinders of the engine, close to the heat generation center of gravity G of the combustion of all the cylinders to heat generation centroid reference value G _0. Preferably, to match the heat generation center of gravity G of the combustion of all the cylinders to heat generation centroid reference value G _0. Thereby, the dispersion | variation in the combustion fluctuation between the cylinders of an engine can be reduced effectively.

  Further, using the information on the angular velocity and angular acceleration of the crankshaft C based on the division angle patterns having different boundary positions between the division angles, the fuel injection timing and the correction amount of the fuel injection amount are calculated by each division angle pattern. Since it did in this way, the problem that the change of the angular velocity produced in the vicinity of the boundary between the division angles of a crank angle is hard to be reflected in angular acceleration can be solved. Thereby, the dispersion | variation in the combustion fluctuation | variation for every cylinder can be grasped | ascertained more correctly.

  The engine E of this embodiment is a diesel engine, that is, a compression self-ignition engine, and the combustion control means 24 can switch the operation mode between the premixed combustion mode and the diffusion combustion mode.

  In general, the fuel injection timing is set to the advance side as the engine speed increases, and is set to the advance side as the engine load increases. In the same operation state, the fuel injection timing set in the premixed combustion mode is usually set to an advance side with respect to the fuel injection timing set in the diffusion combustion mode. In the premixed combustion mode, the mixing period (premixing period) before the ignition of the intake air and the fuel in the combustion chamber is ensured by the advance of the fuel injection timing.

  Here, the premixed combustion refers to a form in which the injected fuel burns in a state where it is diffused and vaporized by the compression top dead center and mixed with air in advance. In premixed combustion, the fuel distribution in the mixture can be made more uniform by utilizing a relatively long ignition delay period from fuel injection, so that smoke is difficult to be generated, and most of the fuel in the mixture is once It is easy to obtain strong heat generation because it can reach a state where self-ignition is possible. Utilizing these characteristics, more reflux gas can be introduced and the combustion temperature can be lowered, so that nitrogen oxides (NOx) can be maintained while maintaining high combustion with high isovolume near compression top dead center. ) And combustion noise can be suppressed. However, since the combustion temperature is low, there is a characteristic that a misfire is easily caused in response to a transient intake amount, a response delay of the recirculated gas, and a change in environmental conditions such as temperature.

  Diffusion combustion is a form in which combustion occurs in the combustible air-fuel mixture layer at the boundary between the injected fuel and the surrounding compressed air. Many diesel engines are operated on the lean side significantly more than 1.0 corresponding to the theoretical air-fuel ratio, and this operating state is a diffusion combustion mode. Since the premixing period (ignition delay period) is not long, the fuel injection timing is retarded compared to premixed combustion. In the diffusion combustion mode, the rich mixture region exists in the immediate vicinity of the ignition region in the combustion chamber.If a large amount of recirculated gas is introduced, the rich mixture in the vicinity of the ignition region falls into an oxygen deficient state. Will cause an increase in smoke. Therefore, a large amount of reflux gas cannot be introduced as much as premixed combustion in order to generate nitrogen oxides (NOx) and suppress combustion noise. Therefore, in order to suppress combustion noise, it is necessary to set the injection timing further to the retard side. Since the combustion temperature is high because the recirculated gas cannot be introduced in large quantities, it is the diffusion combustion mode that is unlikely to cause misfire due to transient response, environmental conditions, and the like.

  For this reason, the application of correction amounts based on a plurality of angular velocities and angular accelerations obtained based on the plurality of types of partition angle patterns is set to be performed in the diffusion combustion mode. When the control state of the engine E is the premixed combustion mode, the fuel burns in the vicinity of the compression top dead center of the piston P. Therefore, even if the control by the second partition angle pattern is not used, the control by the first partition angle pattern is performed. Only with this, sufficiently stable combustion is possible. In the case of diffusion combustion, the possibility of misfire is relatively high depending on the operating state, and therefore, correction amounts based on a plurality of types of partition angle patterns are applied.

  The operation of the engine control device and its control method will be described based on the flowchart of FIG.

Step S1 shown in FIG. 7 is based on a predetermined angle elapsed time T ₄ , T ₅ , T ₆ that is a time for passing a predetermined rotation angle (30 degrees) based on the first division angle pattern. The angular velocities ω ₄ , ω ₅ , ω ₆ while passing through the rotation angle (30 degrees) are calculated, and the angular accelerations α ₄₅ , α ₅₆ calculated based on the angular velocities ω ₄ , ω ₅ , ω ₆ are calculated. It is a journey.

In step S2, based on the angular accelerations α ₄₅ and α ₅₆ calculated in step S1, a change in angular acceleration, that is, a process of calculating a difference Δα = α ₅₆ −α ₄₅ between the two angular accelerations α ₅₆ and α ₄₅ is performed. It is.

In step S3, the heat generation gravity center G1 based on the first division angle pattern is estimated based on the angular acceleration change Δα = α ₅₆ -α ₄₅ calculated in step S2 and the torque condition and the engine speed condition. It is a journey.

Step S1 ′ is based on a predetermined angle elapse time T ₄ ′, T ₅ ′, T ₆ ′, which is a time for passing a predetermined rotation angle (30 degrees), based on the second division angle pattern. The angular velocities ω ₄ ′, ω ₅ ′, ω ₆ ′ while passing through the rotation angle (30 degrees) are calculated, and the angular acceleration α ₄₅ calculated based on the angular velocities ω ₄ ′, ω ₅ ′, ω ₆ ′. This is the process of calculating ', α ₅₆ '.

In step S2 ′, based on the angular accelerations α ₄₅ ′ and α ₅₆ ′ calculated in step S1 ′, the angular acceleration changes, that is, the difference Δα ′ = α ₅₆ between the two angular accelerations α ₅₆ ′ and α ₄₅ ′. This is the process of calculating “−α ₄₅ ”.

Step S3 ', the steps S2' and calculated by the angular acceleration change in _{Δα '= α 56' -α 45} ', torque conditions, based on the condition of the engine speed, the heat generation based on the second sectioning angle pattern This is a process of estimating the center of gravity G2.

Step S4 is likewise torque conditions, based on the condition of the engine speed, a step for estimating the heat generation centroid reference value G _0.

Step S5, the step S3, the heat generation centroid G1 which is calculated in S4, the step S3 ', S4' thermogenesis centroid G2 are calculated by, on the basis of the heat generation centroid reference value G _0, the fuel injection timing correction This is the process of calculating the quantity. Correction amount is compared with the heat generation centroid G1 and heat generation centroid reference value G _0, in comparison with the heat generating centroid G2 and heat generation centroid reference value G _0, it is adopted larger absolute value is.

Step S6 is a process of commanding the correction. Note that, in step S6, the heat generation center of gravity G, when close from G1 or G2 to the heat generating centroid reference value G _0, or in a state of being matched to the generated torque and the target torque of each cylinder are different, need Accordingly, it is possible to perform control to increase or decrease the fuel injection amount for the specific cylinder. That is, the employed correction amount is applied to the current fuel injection timing and the set value of the fuel injection amount in the engine E in operation.

  FIG. 8 is a graph showing the relationship between the in-cylinder pressure of the cylinder and the crank angle in the upper stage, and the relationship between the heat generation rate and the crank angle in the lower stage.

  In the upper diagram, the amount of exhaust recirculation gas contained in the air-fuel mixture introduced into the cylinder increases in the order of a chain line, a broken line, and a solid line. The fuel injection timing is constant. As the amount of exhaust gas in the exhaust gas increases, the peak height of the in-cylinder pressure after top dead center tends to gradually decrease. Further, the peak position tends to be gradually delayed. Further, it is considered that when the amount of the exhaust recirculation gas is increased, it eventually leads to misfire.

  In the middle diagram, the amount of exhaust recirculation gas contained in the air-fuel mixture introduced into the cylinder similarly increases in the order of a chain line, a broken line, and a solid line. As the exhaust gas flow increases, the peak of the heat generation rate (instantaneous value) per unit angle after top dead center tends to gradually decrease. Further, the peak position tends to be gradually delayed. Further, as the exhaust gas flow increases, the heat generation rate (instantaneous value) tends to move to the retarded side as a whole, and it can be understood that the position of the heat generation center of gravity G is delayed.

  FIG. 9 is a graph showing the relationship between the time required for the crankshaft to rotate 30 degrees and the crank angle in the upper stage, and the relationship between the rotational angular acceleration of the crankshaft and the crank angle in the lower stage. Here, the numerical values in the graph are based on the first division angle pattern, but the same applies to the case of being based on the second division angle pattern.

In the upper diagram, the amount of exhaust recirculation gas contained in the air-fuel mixture introduced into the cylinder similarly increases in the order of a chain line, a broken line, and a solid line. Along with the increase in the amount of exhaust recirculation gas, the decrease in the predetermined angle elapsed times T ₃ and T ₄ immediately before the top dead center (region 3) and in the vicinity of the top dead center (region 4) is remarkable. Conversely, the predetermined angle elapsed times T ₅ and T ₆ slightly increase after the top dead center (regions 5 and 6).

In the lower diagram, the change in the amount of exhaust recirculation gas for each chain line, broken line, and solid line is the same as described in the above example. As the exhaust gas flow increases, the angular acceleration α ₃₄ between the region 3 immediately before the top dead center and the region 4 near the top dead center slightly increases, and conversely, between the region 4 and the region 5 after the top dead center. The angular acceleration α ₄₅ in FIG. 6 decreases, and similarly, the angular acceleration α ₅₆ between the region 5 and the region 6 decreases.

Therefore, the difference Δα = α ₅₆ −α ₄₅ between the angular accelerations α ₅₆ and α ₄₅ tends to become smaller before and after the top dead center as the exhaust gas flow increases. Further, the decrease in angular velocity and the decrease in angular acceleration after the top dead center causes the combustion progress rate to be slow, and it is considered that the heat generation center of gravity G has moved to the retard side.

  FIG. 10 is a graph showing the relationship between the change in the rotational angular acceleration α of the crankshaft C and the heat generation gravity center G. Similarly, the numerical values in the graph are based on the first division angle pattern, but the same applies to the case of the second division angle pattern.

Based on the difference Δα = α ₅₆ −α ₄₅ between the angular accelerations α ₅₆ and α _{45 on} the vertical axis, the heat generation gravity center G of that cycle in the cylinder is estimated, and the heat generation gravity center G is the heat generation gravity center reference value. When the timing is later than G ₀ , as shown by the arrow on the right side of the figure, the fuel injection timing is advanced from the current time so that the heat generation gravity center G approaches the heat generation gravity center reference value G _0. I do.

Conversely, if the heat generated center of gravity G is in the early than the heat generating centroid reference value G _0, as indicated by the arrow on the left side of the figure, so as to bring the heat generation center of gravity G to the heat generating centroid reference value G ₀ In addition, control is performed to retard the fuel injection timing from the current state.

  At that time, the required retard amount and advance amount of the fuel injection timing can be calculated by the combustion control means 24 based on a map diagram and the like held by the electronic control unit 20.

  FIGS. 11A to 11C are graphs showing the relationship between the torque generated by the engine E and the heat generation center of gravity, the noise and the heat generation center of gravity G, and the rotational angular acceleration change of the crankshaft C and the heat generation center of gravity G, respectively. is there. 11D to 11F are graphs showing the relationship between the torque generated by the engine E and the heat generating gravity center G, the noise and the heat generating gravity center G, and the rotational angular acceleration change of the crankshaft C and the heat generating gravity center G, respectively. It is.

  As indicated by the arrow in FIG. 11A, when the exhaust gas flow rate is increased and the excess air ratio is gradually decreased from 1.37 to 1.31, 1.29, the heat generation center of gravity G is delayed. Move to the corner side. At this time, torque also decreases.

  However, if the fuel injection timing is gradually advanced from the crank angle after top dead center of 6.5 deg to 7.5 deg, 8.5 deg, 9.5 deg, 11.5 deg while the excess air ratio is 1.29. It can be seen that the heat generation center of gravity G is also moved to the advance side. At this time, the torque also increases and recovers to the level before increasing the amount of exhaust reflux gas.

At this time, as shown in FIG. 11B, the noise level from the engine decreases with the movement of the heat generation gravity center G toward the retard side, and increases with the movement of the heat generation gravity center G toward the advance side. Yes.
Further, as shown in FIG. 11 (c), the change in the angular acceleration of the crankshaft C increases as the heat generation center of gravity G moves toward the retard side, and decreases as the heat generation center of gravity G moves toward the advance side. ing.

  Further, as indicated by an arrow in FIG. 11 (d), when the supercharging pressure is gradually decreased from 108 kPa to 103 kPa and 101 kPa, the heat generation gravity center G decreases toward the retarded side as the air amount (oxygen amount) decreases. Move. At this time, torque also decreases.

  However, if the fuel injection timing is gradually advanced from the crank angle after top dead center of 6.5 deg to 7.5 deg, 8.5 deg, 9.5 deg, 11.5 deg with the supercharging pressure of 101 kPa, It can be seen that the generated center of gravity G has also moved to the advance side. At this time, the torque also increases and recovers to the level before reducing the supercharging pressure.

At this time, as shown in FIG. 11 (e), the noise level from the engine decreases with the movement of the heat generation gravity center G toward the retard side, and increases with the movement of the heat generation gravity center G toward the advance side. Yes.
Further, as shown in FIG. 11 (f), the change in the angular acceleration of the crankshaft C increases as the heat generation center of gravity G moves toward the retard side, and decreases as the heat generation center of gravity G moves toward the advance side. ing.

  In the above embodiment, the combustion state calculation means 23 calculates the heat generation gravity center G in the cylinder based on the change in angular acceleration calculated by the angular acceleration calculation means 22, and performs control based on the heat generation gravity center G. Although performed, other than the heat generation center of gravity G may be adopted as an index serving as a source of control calculated by the combustion state calculation means 23.

  For example, based on the change in angular acceleration calculated by the angular acceleration calculating means 22, the heat generation amount in the cylinder is a predetermined range ratio of 30% or 40% with respect to the total heat generation amount of one cycle. The predetermined time may be calculated by the combustion state calculation means 23.

At this time, the combustion control means 24 controls the combustion in the cylinder by comparing the predetermined time calculated by the combustion state calculating means 23 with a predetermined heat generation time reference value.
If the integrated value of the heat generation amount in the cylinder of the cycle is 30% with respect to the total heat generation amount of one cycle, the heat generation time reference value also corresponds to the predetermined time of 30%. If the integrated value of the heat generation amount in the cylinder of the cycle is 40% of the total heat generation amount of one cycle, the heat generation time reference value also corresponds to the predetermined time of 40%. The reference value to be used.

  In each of the above embodiments, a diesel engine that is a compression self-ignition engine has been described as an example. it can. The present invention can also be applied to reciprocating engines used in various transportation equipment other than automobiles and industrial machines.

  In the case of a gasoline engine, the configuration of the engine is provided with a spark plug for igniting the fuel in the combustion chamber at the upper part of the cylinder shown in FIG. The ignition timing of the spark plug is controlled by the control means 26 of the electronic control unit 20.

In the case of a gasoline engine as well, for example, based on the difference Δα = α ₅₆ −α ₄₅ between the angular accelerations α ₅₆ and α ₄₅ of the crankshaft C, based on the first division angle pattern, as in the above-described embodiment. Then, the heat generation center of gravity G1 of the one cycle in the cylinder is estimated. Further, based on the difference Δα ′ = α ₅₆ ′ −α ₄₅ ′ between the angular accelerations α ₅₆ ′ and α ₄₅ ′ of the crankshaft C based on the second division angle pattern, the one cycle of the cylinder is determined. The heat generation center of gravity G2 is estimated.

When the heat generating centroid G1 and G2 is in the late than the heat generating centroid reference value G ₀ is the heat generation centroid G1 and G2 as close to the heat generating centroid reference value G _0, the fuel injection timing and the ignition timing A correction value for advancing the angle etc. from the current state is calculated. The comparison of the correction amount is the same as that of the diesel engine.

Conversely, if the heat generated centroid G1 and G2 has become earlier than the heat generating centroid reference value G ₀ is the heat generation centroid G1 and G2 as close to the heat generating centroid reference value G _0, the fuel injection timing And a correction value for retarding the ignition timing and the like from the current state. The comparison of the correction amount is the same as that of the diesel engine.

Necessary fuel injection timing and retard amount and advance amount of the ignition timing can be calculated by the combustion control means 24 based on a map diagram held by the electronic control unit 20. Electronic control unit 20, the heat generated centroid reference value G ₀ and heat generated timing reference value, even that owns calculated data related to the target torque is the same as in the case of diesel engines.

  In the above embodiment, the angular velocity detection means 21 calculates the angular velocity of rotation of the crankshaft C for each division angle using each of the first division angle pattern and the second division angle pattern. The division angle pattern is not limited to two, and three, four, or more different division angle patterns may be used.

  As another example of calculating the correction amount, the angular acceleration calculation means 22 calculates an angular acceleration by selecting one angular speed from a plurality of angular speeds obtained based on a plurality of types of dividing angular patterns, and the combustion control means 24 The correction amount for the set value of the fuel injection timing or the fuel injection amount adopted for controlling the combustion may be calculated and applied based on the angular acceleration based on the selected angular velocity. As to which division angle pattern information is adopted when selecting one angular velocity, for example, the one having a larger absolute value of angular acceleration can be adopted.

  Further, the angular velocity employed by the angular acceleration calculating means 22 to calculate the angular acceleration may be an angular velocity based on a division angle pattern that is different for each cycle of the engine E, as in the above embodiment. An angular velocity based on both division angle patterns may be acquired for each cycle of the engine E.

  In the above embodiment, the combustion control means 24 controls the engine E based on the index of the heat generation center of gravity G. Instead of the index of the heat generation center of gravity G, the combustion control means 24 calculates the angular acceleration. The ignition timing in the combustion chamber may be calculated based on the change in the angular acceleration calculated by the means 22, and the correction amount may be calculated by comparing the ignition timing with a predetermined ignition timing reference value.

1, 11 Intake passage 2 Exhaust passage 3 High-pressure exhaust recirculation passage 4 High-pressure exhaust recirculation valve 5 High-pressure throttle valve 6 Intake cooling device (intercooler)
7 Turbine 8 Exhaust gas purification unit 12 Silencer 13 Low pressure exhaust gas recirculation passage 14 Low pressure exhaust gas recirculation valve 15 Low pressure throttle valve 20 Electronic control unit 21 Angular velocity detection means 22 Angular acceleration calculation means 23 Combustion state calculation means 24 Combustion control means 25 Fuel injection execution means 26 Control means 30 Crank angle sensor 33 Cylinder discrimination sensor

Claims (9)

A crankshaft that rotates with the output of the engine,
Angular velocity detection means for calculating an angular velocity of rotation of the crankshaft based on a division angle set to a crank angle of the crankshaft;
Angular acceleration calculation means for calculating angular acceleration from angular velocities corresponding to two division angles obtained along the time series by the angular velocity detection means;
Combustion control means for controlling combustion in a cylinder based on a change in angular acceleration calculated by the angular acceleration calculation means;
With
The angular velocity detection means has a plurality of types of division angle patterns having different boundary positions between adjacent division angles, and calculates an angular velocity based on each of the plurality of types of division angle patterns. The angular acceleration calculating means calculates angular acceleration by each of a plurality of angular velocities obtained based on a plurality of types of division angle patterns,
The combustion control means calculates a correction amount for the set value of the fuel injection timing or fuel injection amount employed for controlling the combustion based on the angular acceleration based on the angular velocity based on different partition angle patterns, and is calculated. The engine control device according to claim 1, wherein a plurality of correction amounts are compared and the correction amount having the largest absolute value is applied. The angular velocity detection means sequentially calculates a plurality of angular velocities obtained based on a plurality of types of dividing angle patterns for each cycle of the crankshaft,
The engine control device according to claim 2, wherein the angular acceleration calculation means calculates angular acceleration based on angular velocities based on different division angle patterns calculated in order. The angular velocity detection means simultaneously calculates a plurality of angular velocities obtained based on a plurality of types of division angle patterns during one cycle of the crankshaft,
The engine control device according to claim 2, wherein the angular acceleration calculation means calculates angular acceleration based on angular velocities based on different division angle patterns calculated simultaneously. The engine is a compression self-ignition engine;
The combustion control means can switch between premixed combustion and diffusion combustion,
The engine control device according to any one of claims 1 to 4, wherein the application of correction amounts based on a plurality of angular velocities and angular accelerations obtained based on a plurality of types of partition angle patterns is performed only during diffusion combustion. The combustion control means calculates a predetermined time when the heat generation amount in the cylinder is a predetermined ratio with respect to the total heat generation amount of one cycle based on the change in angular acceleration calculated by the angular acceleration calculation means, The engine control apparatus according to any one of claims 1 to 5, wherein the correction amount is calculated by comparing the predetermined time with a predetermined heat generation time reference value. The engine control device according to claim 6, wherein the predetermined time is a heat generation center of gravity, and the heat generation time reference value is a heat generation center of gravity reference value. The combustion control means calculates an ignition timing based on a change in angular acceleration calculated by the angular acceleration calculation means, and calculates the correction amount by comparing the ignition timing with a predetermined ignition timing reference value. The engine control device according to any one of claims 1 to 7. The angular acceleration calculating means calculates an angular acceleration by selecting one angular velocity from a plurality of angular velocities obtained based on a plurality of types of division angular patterns,
2. The combustion control means calculates and applies a correction amount for a set value of a fuel injection timing or a fuel injection amount employed for controlling combustion based on an angular acceleration based on the selected angular velocity. The control apparatus of the engine of any one of -8.

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