JP6901324B2 - Ignition timing adjustment method and ignition timing adjustment device - Google Patents

Description

The present invention relates to an ignition timing matching method for an internal combustion engine and an ignition timing matching device.

The ignition timing control of the internal combustion engine is, for example, the ignition timing in each operating state (for example, the ignition timing at which the torque of the internal combustion engine is maximized) determined by the rotation speed and the load (for example, the intake air amount) of the internal combustion engine. An ignition timing map showing a certain MBT (Internal Combance for Best Torque) is stored in ROM in advance, and the ignition timing map is searched to extract the ignition timing according to the operating state, and the ignition plug is used at this ignition timing. Ignite.

As an ignition timing adaptation method used in this ignition timing map, for example, an output shaft (crankshaft) of an internal combustion engine is connected to a dynamometer, and the ignition timing is advanced by a predetermined angle for each of a plurality of operating states. , There is a method of detecting the shaft torque of an internal combustion engine with a dynamometer and searching for an MBT having the maximum shaft torque as shown in FIG. 7 (see, for example, Patent Document 1).

Further, as another applicable method, for example, the output shaft of the internal combustion engine is connected to the dynamometer, the ignition timing is advanced by a predetermined angle for each of a plurality of operating states, and the in-cylinder pressure sensor is used at each crank angle. There is a method of detecting the in-cylinder pressure (combustion pressure) of the cylinder of an internal combustion engine, extracting the maximum in-cylinder pressure point or 50% combustion point from the combustion pressure waveform, and setting the MBT from this maximum in-cylinder pressure point or 50% combustion point. (See, for example, Patent Document 2).

JP-A-2007-177825 Japanese Unexamined Patent Publication No. 59-39974

However, when the MBT is set using the shaft torque, the peak value is searched from the data of the shaft torque at each ignition timing advanced within a predetermined angle range, so this search takes time. In particular, as shown in FIG. 8, if there is an ignition timing region A in which the value of the shaft torque hardly changes, this region A is repeatedly searched to set the MBT, so that the search time becomes long.

When the MBT is set using the combustion pressure, the combustion pressure waveform (for example, peak value, rising edge, falling edge) is generated when a parameter that affects the combustion state of the internal combustion engine such as EGR (Exhaust Gas Recirculation) is added. As it changes, the maximum in-cylinder pressure point and the 50% combustion point change, making it more difficult to set an appropriate MBT.

The present invention has been made to solve the above problems, and provides an ignition timing matching method and an ignition timing matching device capable of setting an appropriate ignition timing while shortening the ignition timing search time. The purpose is to provide.

The ignition timing adaptation method according to the present invention includes an ignition timing changing step for changing the ignition timing of the internal combustion engine, and a crankshaft crank for each ignition timing changed in the ignition timing changing step, and for each crankshaft angle of the internal combustion engine. The maximum rotational force is obtained from the rotational force acquisition process for acquiring the rotational force acting in the tangential direction of the virtual circle formed by the rotation of the arm and the rotational force data for each crankshaft angle acquired in the rotational force acquisition process. When the maximum rotational force timing is determined in the rotational force maximum timing determination step and the rotational force maximum timing determination step, which determines whether or not the extracted angle is the preset maximum rotational force timing. It is characterized by including an ignition timing setting step of setting an ignition timing at which the torque of the internal combustion engine is maximized according to the ignition timing.

In the ignition timing adaptation method according to the present invention, the rotational force acting in the tangential direction of the virtual circle formed by the rotation of the crank arm is acquired for each angle of the crankshaft for each changed ignition timing. The torque acting on the crankshaft (shaft torque of the internal combustion engine) is generated by the rotational force acting in the tangential direction. Therefore, at the timing when this rotational force becomes maximum, the shaft torque of the internal combustion engine also becomes maximum. Therefore, in the ignition timing adaptation method according to the present invention, the angle at which the rotational force is maximized is extracted from the rotational force data for each angle of the crankshaft, and the angle is the maximum rotational force timing (predetermined determination angle). It is determined whether or not, and the ignition timing (MBT) at which the torque of the internal combustion engine is maximized is set according to the ignition timing when it is determined to be the maximum rotational force timing. In this way, by determining whether or not the angle of the peak value of the rotational force data (rotational force waveform) for each crankshaft angle for each ignition timing under search is the maximum rotational force timing, the internal combustion engine Since the ignition timing at which the torque is maximized can be searched, the search time can be shortened. Further, the rotational force acting in the tangential direction is a coefficient in which the force acting on the piston according to the in-cylinder pressure (combustion pressure) of the cylinder of the internal combustion engine changes according to the angle of the crankshaft obtained from the specifications of the internal combustion engine. Is the force transformed by. Due to the coefficient that changes according to the angle of the crankshaft, the angle of the crankshaft that maximizes the rotational force (maximum rotational force timing) even if parameters such as EGR that affect the combustion state in the cylinder of the internal combustion engine are added. Does not change. Therefore, an appropriate ignition timing can be set even if the parameters that affect the combustion state are changed. As described above, according to the ignition timing adaptation method according to the present invention, it is possible to set an appropriate ignition timing while shortening the search time for the ignition timing.

In the ignition timing adaptation method according to the present invention, the rotational force acquisition step detects the in-cylinder pressure of the cylinder of the internal combustion engine for each angle of the crankshaft and acts in the axial direction of the piston of the cylinder obtained from the detected in-cylinder pressure. It is preferable to obtain the rotational force for each angle of the crankshaft by the force and the mechanical transmission efficiency of transmitting the axial force of the piston obtained from the specifications of the internal combustion engine in the tangential direction of the virtual circle. With this configuration, by using the mechanical transmission efficiency geometrically obtained from the specifications of the internal combustion engine according to the angle of the crankshaft, a virtual circle of the crankshaft is generated from the force acting in the axial direction of the piston. It can be converted into a rotational force acting in the tangential direction of, and the rotational force can be obtained with high accuracy.

In the ignition timing adaptation method according to the present invention, in the rotational force acquisition step, the rotational force is set to Fi (θ) [N], the crankshaft angle is set to θ [deg], and the in-cylinder pressure is set to P (θ) [kPa]. When the cross-sectional area of the piston is A [mm ² ], the length of the connecting rod is l [mm], and the crank radius of the crankshaft is r [mm], the rotational force Fi (θ) is obtained by (Equation 1). ) Is preferably calculated. With this configuration, according to (Equation 1), the rotational force can be accurately obtained by using the in-cylinder pressure, the angle of the crankshaft, and the specifications of the internal combustion engine.

In the ignition timing adaptation method according to the present invention, the in-cylinder pressure of the cylinder of the internal combustion engine is detected for each angle of the crank shaft, and the combustion energy in the cylinder is acquired using the data of the in-cylinder pressure for each angle of the detected crank shaft. Combustion energy acquisition process, storage process to store the combustion energy acquired in the combustion energy acquisition process, combustion energy acquired in the combustion energy acquisition process, and combustion energy stored in the storage process at the previous ignition timing. The ignition timing setting step includes the combustion energy determination step of determining the magnitude relationship of the above, and the ignition timing setting step is determined to be the maximum rotational force timing preset in the rotational force maximum timing determination step based on the determination result in the combustion energy determination step. In this case, it is preferable to set the ignition timing with the highest combustion energy as the ignition timing with the maximum torque of the internal combustion engine. With this configuration, the ignition timing with the highest combustion energy is set as the ignition timing with the maximum torque of the internal combustion engine. Therefore, even if there are a plurality of ignition timings when the rotational force becomes the maximum timing, the plurality of ignition timings are set. It is possible to set an appropriate ignition timing at which the torque of the internal combustion engine is maximized from the ignition timing of.

In the ignition timing adaptation method according to the present invention, in the combustion energy acquisition step, the in-cylinder pressure is integrated in a predetermined angle range using the data of the in-cylinder pressure for each angle of the crankshaft, and the integrated value is used as the combustion energy. Is preferable. By integrating the in-cylinder pressure within a predetermined angle range in this way, the combustion energy can be obtained with high accuracy.

The ignition timing adjusting device according to the present invention includes a crank angle detection means for detecting the angle of the crankshaft of the internal combustion engine, an ignition timing changing means for changing the ignition timing of the internal combustion engine, and an ignition changed by the ignition timing changing means. Obtained by the rotational force acquisition means and the rotational force acquisition means that acquire the rotational force acting in the tangential direction of the virtual circle formed by the rotation of the crankarm of the crankshaft for each period and the angle of the crankshaft of the internal combustion engine. An angle that maximizes the rotational force is extracted from the data of the rotational force for each angle of the crankshaft, and a means for determining the maximum rotational force timing that determines whether or not the extracted angle is the preset maximum rotational force timing. It is characterized by including an ignition timing setting means for setting an ignition timing at which the torque of the internal combustion engine is maximized according to the ignition timing when the maximum rotational force timing is determined by the maximum rotational force timing means. According to the ignition timing matching device according to the present invention, the ignition timing matching device operates in the same manner as the ignition timing matching method according to the present invention described above, so that it is possible to set an appropriate ignition timing while shortening the ignition timing search time. ..

The ignition timing matching device according to the present invention includes an in-cylinder pressure detecting means for detecting the in-cylinder pressure of the cylinder of an internal combustion engine, and the rotational force acquiring means is based on the in-cylinder pressure detected by the in-cylinder pressure detecting means for each angle of the crankshaft. Rotation of the crankshaft for each angle by the force acting in the axial direction of the piston of the obtained cylinder and the mechanical transmission efficiency of transmitting the axial force of the piston obtained from the specifications of the internal combustion engine in the tangential direction of the virtual circle. It is preferable to obtain force. With this configuration, it operates in the same manner as the ignition timing adaptation method according to the present invention described above, and the rotational force can be obtained with high accuracy.

In the ignition timing matching device according to the present invention, the combustion energy acquisition means for acquiring the combustion energy in the cylinder using the data of the in-cylinder pressure detected by the in-cylinder pressure detecting means for each angle of the crank shaft, and the combustion energy acquisition means. A storage means for storing the acquired combustion energy, a combustion energy determination means for determining the magnitude relationship between the combustion energy acquired by the combustion energy acquisition means and the combustion energy stored in the storage means at the previous ignition timing, and The ignition timing setting means has the largest combustion energy among the ignition timings when the maximum rotational force timing is determined in advance by the maximum rotational force timing determination means based on the determination result in the combustion energy determination means. It is preferable to set the ignition timing as the ignition timing at which the torque of the internal combustion engine is maximized. With this configuration, it operates in the same manner as the ignition timing adaptation method according to the present invention described above, and an appropriate ignition timing that maximizes the torque of the internal combustion engine can be set from a plurality of ignition timings.

According to the present invention, it is possible to set an appropriate ignition timing while shortening the search time for the ignition timing.

It is a block diagram which shows the structure of the ignition timing adaptation system which concerns on embodiment. It is a figure which shows typically the structure of the engine shown in FIG. It is a figure which shows an example of in-cylinder pressure, machine transmission efficiency, and rotational force according to a crank angle. It is a flowchart which shows the flow of the process in the ignition timing adaptation apparatus of the ignition timing adaptation system which concerns on embodiment. It is a figure which shows an example of the relationship between the maximum rotational force timing and shaft torque when exhaust gas is not recirculated by EGR. It is a figure which shows an example of the relationship between the maximum rotational force timing, and the shaft torque when the exhaust gas is recirculated by EGR. It is a figure which shows an example of the relationship between the ignition timing and the shaft torque of an engine. It is a figure which shows another example of the relationship between the ignition timing and the shaft torque of an engine.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the figure, the same reference numerals are used for the same or corresponding parts. Further, in each figure, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

The configuration of the ignition timing adaptation system 1 according to the embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of an ignition timing adaptation system 1 according to an embodiment.

The ignition timing adaptation system 1 is a system that searches for an MBT of the ignition timing of the engine 2 and creates an ignition timing map. The ignition timing adaptation system 1 includes an engine 2 (corresponding to the internal combustion engine described in the claims), a dynamometer 3, a control device 4, and an ignition timing adaptation device 5.

The ignition timing map is, for example, a map in which MBT (adapted value) is associated with a large number of operating states including each value of the engine speed and each value of the load (for example, intake air amount). Alternatively, it is a multidimensional map in which MBT (adapted value) is associated with each device value combination of a plurality of devices provided in the engine 2 in addition to each value of the engine 2 rotation speed and the load. In the case of the ignition timing map in which the MBT is associated with each operating state consisting of the above-mentioned rotation speed and load, for example, any ignition timing searched from this ignition timing map is the device value of each device. It is corrected using each coefficient set according to, and this corrected ignition timing is used in the ignition control of the engine.

The ignition timing adaptation system 1 sequentially sets an arbitrary operating state (arbitrary rotation speed, arbitrary load) and a target value of each device of the engine 2 by automatic operation, and searches for an MBT while advancing the ignition timing. .. When the MBT is searched for one operating state, the MBT is searched for the next operating state. Further, in a certain operating state, MBTs are searched for by changing the combination of target device values of a plurality of devices provided in the engine 2.

The engine 2 is an engine to be tested, for example, a horizontally opposed 4-cylinder gasoline engine. The engine 2 includes a plurality of cylinders, and a spark plug is provided for each cylinder. Further, the engine 2 is provided with various devices, for example, a throttle valve, an injector, a VVT (Variable Valve Timing), an EGR valve, and a TGV (Tumble Generation Valve). With these various devices, it is possible to change parameters that affect the combustion state of the engine 2, such as intake air amount, fuel injection amount, intake / exhaust valve opening / closing timing, EGR rate, and presence / absence of tumble vortex. The crankshaft 2a (output shaft) of the engine 2 is connected to the dynamometer 3.

The crankshaft 2a of the engine 2 is provided with a crank angle sensor 10 (corresponding to the crank angle detecting means described in the claims) for detecting the crank angle (rotation angle of the crankshaft 2a). Each cylinder of the engine 2 is provided with an in-cylinder pressure sensor 11 (corresponding to the in-cylinder pressure detecting means described in the claims) for detecting the in-cylinder pressure. The engine 2 is connected to the control device 4 and is controlled by the control device 4.

The dynamometer 3 is a test device for measuring the performance of a single engine. The dynamometer 3 absorbs the torque generated by the engine 2 and detects the torque of the engine 2. The dynamometer 3 is connected to the control device 4.

The control device 4 controls the operating state of the engine 2. The control device 4 is connected to the ignition timing matching device 5. The control device 3 controls the ignition of the spark plug of the engine 2 based on the ignition timing set by the ignition timing matching device 5. Further, the control device 3 controls each device based on the target device value for each device of the engine 2 set by the ignition timing matching device 5.

A crank angle sensor 10 is connected to the control device 4, and the crank angle detected by the crank angle sensor 10 is input. The in-cylinder pressure sensor 11 of each cylinder is connected to the control device 4, and the in-cylinder pressure detected by the in-cylinder pressure sensor 11 is input.

The ignition timing matching device 5 searches for an MBT (fitting value) for each operating state of the engine 2. In particular, the ignition timing matching device 5 searches for the MBT using the maximum rotational force timing, which is the crank angle at which the rotational force is maximum. The ignition timing matching device 5 is configured on, for example, a personal computer. The detection values of the sensors 10 and 11 are input to the ignition timing matching device 5 via the control device 4.

Before the ignition timing matching device 5 is specifically described, the rotational force and the maximum rotational force timing will be described with reference to FIG. FIG. 2 is a diagram schematically showing the configuration of the engine 2. FIG. 2 schematically shows the cylinder 2b and the piston 2c of the cylinder of the engine 2, the connecting rod 2d, and the crank arm 2e of the crankshaft 2a.

The piston 2c reciprocates (linearly) in the cylinder 2b. The reciprocating motion of the piston 2c is changed to a rotary motion by the connecting rod 2d and the crankshaft 2a, and the crank arm 2e rotates. FIG. 2 shows a virtual circle C (a virtual circle consisting of a locus of rotational movement of the connection point between the connecting rod 2d and the crank arm 2e) formed by the rotational movement of the crank arm 2e. The radius of the circle C is the crank radius r. Further, FIG. 2 shows a crank angle θ, a connecting rod angle (inclination angle of the connecting rod 2d) Ψ, and a connecting rod length (length of the connecting rod 2d) l. The crank angle θ is 0 [deg] when the piston 2c is at top dead center (TDC (Top Dead Center)). The connecting rod angle Ψ is 0 [deg] when the piston 2c is at top dead center or bottom dead center (BDC (Bottom Dead Center)).

The in-cylinder pressure P (θ) acts on the piston 2c. The in-cylinder pressure P (θ) changes according to the crank angle θ. The in-cylinder pressure P (θ) corresponds to the combustion pressure generated by combustion in the cylinder 2b. The value obtained by multiplying the in-cylinder pressure P (θ) by the cross-sectional area A of the piston 2c is the force F (θ) acting in the axial direction of the piston 2c. This force F (θ) (force in the linear direction) is transmitted by the connecting rod 2d and the crankshaft 2a, and is changed to a force Fi (θ) acting in the tangential direction of the virtual circle C of the crankshaft 2a. The force Fi (θ) acting in this tangential direction (direction orthogonal to the crank arm 2e) is called "rotational force". The rotational force Fi (θ) changes according to the crank angle θ. Due to this rotational force Fi (θ), the crankshaft 2a rotates, and torque (= Fi (θ) × r) is generated on the crankshaft 2a. Therefore, the torque of the crankshaft 2a (shaft torque of the engine 2) changes according to the rotational force Fi (θ), and the shaft torque of the engine 2 also becomes maximum at the timing when the rotational force Fi (θ) becomes maximum. The crank angle θ when the rotational force Fi (θ) becomes the largest (at the peak value of the rotational force) after the cylinder is ignited is called the “maximum rotational force period”.

The rotational force Fi (θ) is obtained by multiplying the force F (θ) acting in the axial direction of the piston 2c by a coefficient for transmitting the force F (θ) acting in the axial direction in the tangential direction of the virtual circle C. can get. This coefficient changes according to the crank angle θ. This coefficient is called "machine transmission efficiency". The mechanical transmission efficiency is geometrically obtained from the crank angle θ and the specifications of the engine 2 (connecting rod length l and crank radius r).

The ignition timing conforming device 5 includes an operation preparation unit 5a, an ignition timing advance angle unit 5b (corresponding to the ignition timing changing means described in the claims), and a rotational force calculation unit 5c (rotation described in the claims). Maximum rotational force timing determination unit 5d (corresponding to the maximum rotational force timing determination means described in the claims), combustion energy calculation unit 5e (corresponding to the maximum rotational force timing determination means described in the claims), and combustion energy calculation unit 5e (corresponding to the claims). The combustion energy determination unit 5f (corresponding to the combustion energy determination means described in the claims) and the MBT setting unit 5g (corresponding to the ignition timing setting means described in the claims). Have. Each of the processing units 5a to 5g is realized, for example, by executing an ignition timing matching application program in a personal computer.

The ignition timing matching device 5 is provided with a storage unit 5h (corresponding to the storage means described in the claims). The storage unit 5h is configured in, for example, a predetermined area of the RAM of a personal computer.

The operation preparation unit 5a sets the rotation speed and load of the engine 2 in the next operating state every time the search for the MBT (adapted value) in an arbitrary operating state is completed, and sends the rotation speed and load to the control device 4. Output. Further, the operation preparation unit 5a sets a target device value for each device of the engine 2 described above for each operation state, and outputs the target device value of each device to the control device 4.

The ignition timing advance unit 5b sets the ignition timing of the engine 2 at a predetermined angle (for example, 1 from top dead center) in each state of the engine 2 including the operating state set by the operation preparation unit 5a and the target device value of each device. [Deg]) is advanced in increments, and the advanced ignition timing [deg BTDC] is output to the control device 4.

The rotational force calculation unit 5c has an in-cylinder pressure P detected by the in-cylinder pressure sensor 11 for each crank angle θ [deg] each time the engine 2 is ignited at the ignition timing advanced by the ignition timing advance unit 5b. Using (θ) [kPa] and the specifications of the engine 2 (cross-sectional area A [mm ² ] of the piston 2c, connecting rod length l [mm], crank radius r [mm]), the rotational force Fi according to (Equation 1) (Θ) Calculate [N]. For example, the rotational force Fi (θ) [N] is calculated for each 1 [deg] in the range of −60 [deg] to 180 [deg] of the crank angle θ.

The calculation formula (Equation 1) of the rotational force Fi (θ) is the mechanical transmission efficiency E (θ) represented by (Equation 3) in addition to the force F (θ) acting in the axial direction of the piston 2c represented by (Equation 2). Is an expression multiplied by. The force F (θ) acting on the piston 2c in the axial direction changes according to the in-cylinder pressure P (θ) (and thus the crank angle θ). The machine transmission efficiency E (θ) changes according to the crank angle (θ).

FIG. 3 shows an example of the in-cylinder pressure P (θ), the mechanical transmission efficiency E (θ), and the rotational force Fi (θ) according to the crank angle θ. In FIG. 3, the horizontal axis is the crank angle [deg], and the change curve of the in-cylinder pressure P (θ) in the range of -60 to 180 [deg] is shown by a alternate long and short dash line, and the change curve of the machine transmission efficiency E (θ) is shown. Is shown by a broken line, and the change curve of the rotational force Fi (θ) is shown by a solid line. In this example, the in-cylinder pressure P (θ) and the rotational force Fi (θ) are those when ignited by MBT.

The in-cylinder pressure P (θ) rises after ignition and increases, and peaks at a crank angle θ1 [deg ATDC] (maximum in-cylinder pressure point) on the retard side of the crank angle θ = 0 [deg] (top dead center). After that, it becomes smaller. The change curve of the in-cylinder pressure P (θ) that changes according to the crank angle θ corresponds to the combustion pressure waveform.

The machine transmission efficiency E (θ) becomes a negative value on the advance angle side (BTDC) from the crank angle θ = 0 [deg] (top dead center), and the negative value gradually increases as the angle advances. Further, the machine transmission efficiency E (θ) becomes a positive value on the retard side (ATDC) of the crank angle θ = 0 [deg] (top dead center), and the positive value gradually increases as the angle is retarded. The machine transmission efficiency E (θ) becomes the maximum efficiency at the crank angle θ3 [deg ATDC] on the retard side, and the positive value gradually decreases from θ3 to 180 [deg ATDC]. In this way, the machine transmission efficiency E (θ) changes from a negative value to a positive value at θ = 0 [deg] (top dead center). Therefore, from the top dead center to the crank angle θ3, which is the maximum efficiency point, the rate at which the force F (θ) acting in the axial direction of the piston 2c is gradually converted into the tangential force of the virtual circle C gradually increases toward the retard angle side. Becomes larger.

The rotational force Fi (θ) is a force F (θ) acting in the axial direction of the piston 2c, which is a value obtained by multiplying the in-cylinder pressure P (θ) described above by the cross-sectional area A (constant value) of the piston 2c for each crank angle θ. It is a value obtained by multiplying θ) by the above-mentioned machine transmission rate E (θ). Therefore, the rotational force Fi (θ) becomes a negative value on the advance angle side (BTDC) from the crank angle θ = 0 [deg] (top dead center), and from the crank angle θ = 0 [deg] (top dead center). Is also a positive value on the retard side (ATDC). In particular, since the mechanical transmission efficiency E (θ) gradually increases up to the crank angle θ3 (> θ1), the in-cylinder pressure P (θ) (force F (θ) acting in the axial direction of the piston 2c) is larger than the crank angle θ1. Even if it becomes smaller on the retard side, the rotational force Fi (θ) becomes larger even after the crank angle θ1, and the crank angle θ2 [deg ATDC] on the retard side of the crank angle θ1 (maximum in-cylinder pressure point). Is the peak value. This crank angle θ2 is the maximum rotational force period.

In this way, the maximum rotational force period (the period when the shaft torque becomes maximum) is determined by the influence of the mechanical transmission efficiency E (θ), which is a positive value on the retard side of the top dead center. In particular, in the vicinity of the top dead center, the mechanical transmission coefficient E (θ) is small, so that the rotational force Fi (θ) is small. Further, since the machine transmission coefficient E (θ) increases from the top dead center to the retard side up to the maximum efficiency point (= θ3), the maximum in-cylinder pressure point of the in-cylinder pressure P (θ) due to this machine transmission efficiency (θ). Even after (= θ1), the rotational force Fi (θ) becomes large.

The rotational force maximum timing determination unit 5d extracts the crank angle at which the rotational force Fi (θ) is maximum from the data of the rotational force Fi (θ) for each crank angle θ calculated by the rotational force calculation unit 5c. Then, the rotational force maximum timing determination unit 5d determines whether or not the extracted crank angle is the rotational force maximum timing determination angle (hereinafter, referred to as “determination angle”). This determination angle is the maximum rotational force timing when the engine is ignited by the MBT. The determination angle is preset by an experiment or the like. In the example shown in FIG. 3, θ2 is preset as the determination angle.

When the crank angle at which the rotational force Fi (θ) is maximized is determined by the rotational force maximum timing determination unit 5d to be the determination angle, the ignition timing at that time is stored in the storage unit 5h as an MBT candidate. On the other hand, when the crank angle at which the rotational force Fi (θ) is maximized is determined by the rotational force maximum timing determination unit 5d to be not the determination angle, the next ignition timing is set by the ignition timing advance angle unit 5b.

The combustion energy calculation unit 5e detects with the in-cylinder pressure sensor 11 when it is determined that the crank angle at which the rotational force Fi (θ) at the ignition timing, which is the maximum rotational force timing determination unit 5d, is the maximum is the determination angle. Using the data of the in-cylinder pressure P (θ) for each crank angle θ, the in-cylinder pressure is integrated in a predetermined angle range to obtain the combustion energy (integrated value). Here, for example, the in-cylinder pressure P (θ) in the range of −60 [deg] to 180 [deg] of the crank angle θ is integrated. In the example shown in FIG. 3, the combustion energy corresponds to the area in the change curve of the in-cylinder pressure P (θ). The combustion energy calculation unit 5e stores the obtained combustion energy in the storage unit 5h.

When the combustion energy at the ignition timing, which is the combustion energy calculation unit 5e, is calculated, the combustion energy determination unit 5f determines the combustion energy at the current ignition timing and the previous ignition timing stored in the storage unit 5h. Determine the magnitude relationship with combustion energy. When the combustion energy determination unit 5f determines that the combustion energy at the current ignition timing is equal to or higher than the combustion energy at the previous ignition timing, the next ignition timing is set by the ignition timing advance angle unit 5b. On the other hand, when the combustion energy determination unit 5f determines that the combustion energy at the current ignition timing is smaller than the combustion energy at the previous ignition timing, the process shifts to the processing by the MBT setting unit 5g.

The MBT setting unit 5g extracts an MBT candidate having a large combustion energy from the MBT candidates stored in the storage unit 5h, and sets the MBT using the extracted MBT candidate. As a method of setting the MBT, for example, when the combustion energy becomes the largest at the ignition timing of the extracted MBT candidate, the MBT candidate (ignition timing) is set as the MBT as it is. When the combustion energy becomes the largest at the ignition timing between the two extracted MBT candidates, the ignition timing at which the combustion energy becomes the largest is obtained using the two MBT candidates, and the ignition timing is set as the MBT. You may.

When the MBT is set by the MBT setting unit 5g, the operation preparation unit 5a sets the next combination of the target device values for each device, or the MBT search for all the combinations of the target device values for each device is completed. In this case, the operation preparation unit 5a sets the rotation speed and the load in the next operation state.

The flow of the MBT search operation in the automatic operation in the ignition timing adaptation system 1 will be described with reference to FIGS. 1 and 2. The operation of the ignition timing adjusting device 5 will be described with reference to the flowchart of FIG. FIG. 4 is a flowchart showing a processing flow in the ignition timing adaptation device 5 of the ignition timing adaptation system 1 according to the embodiment. Here, the flow of operation when the MBT is searched for each combination of the target device values of each device for an arbitrary operating state will be described. In the engine 2, a load is applied by the dynamometer 3 in an arbitrary operating state, and the crankshaft 2a rotates at a rotation speed in the arbitrary operating state.

The ignition timing matching device 5 sets a target device value for each device of the engine 2 (S10). The control device 4 controls each device of the engine 2 so as to have each set target device value.

The ignition timing matching device 5 sets the ignition timing advanced by a predetermined angle (S12). The control device 4 controls the ignition of the engine 2 so as to ignite at the set ignition timing.

During the operation of the engine 2, the crank angle sensor 10 detects the crank angle θ, and the in-cylinder pressure sensor 11 detects the in-cylinder pressure. The ignition timing matching device 5 uses the cross-sectional area A of the piston 2c, the connecting rod length l, the crank radius r, and the in-cylinder pressure P (θ) for each predetermined crank angle θ, and uses the above calculation formula (formula). The rotational force Fi (θ) is calculated according to 1) (S14).

The ignition timing matching device 5 has a crank angle (at the ignition timing set in S12) at which the rotational force Fi (θ) is maximized from the data of the rotational force Fi (θ) for each crank angle θ calculated in the process of S14. The maximum rotational force timing) is extracted, and it is determined whether or not this crank angle is a determination angle (for example, θ2 shown in FIG. 3) (S16). If it is determined in the determination of S16 that the angle is not the determination angle, the ignition timing matching device 5 returns to the process of S12, advances the ignition timing, and sets the next ignition timing.

When it is determined in the determination of S16 that the angle is for determination, the ignition timing matching device 5 stores the current ignition timing as an MBT candidate in the storage unit 5h (S18). The ignition timing matching device 5 integrates the in-cylinder pressure (combustion pressure) in a predetermined angle range using the data (combustion pressure waveform) of the in-cylinder pressure P (θ) for each crank angle θ, and integrates the integrated value (combustion energy). (S20). The ignition timing adjusting device 5 stores the integrated value (combustion energy) at the current ignition timing acquired in the process of S20 in the storage unit 5h (S22).

Is the ignition timing adjusting device 5 smaller than the integrated value (combustion energy) at the current ignition timing acquired in the process of S20 smaller than the integrated value (combustion energy) at the previous ignition timing stored in the storage unit 5h? It is determined whether or not (S24). If the determination in S24 determines that the integrated value at the current ignition timing is equal to or greater than the integrated value at the previous ignition timing, the ignition timing matching device 5 returns to the process of S12 and advances the ignition timing. Set the next ignition timing.

When it is determined in the determination of S24 that the integrated value at the current ignition timing is smaller than the integrated value at the previous ignition timing, the ignition timing matching device 5 uses the MBT candidate stored in the storage unit 5h. The ignition timing with the highest combustion energy is set as the MBT (S26). As a result, in an arbitrary operating state, an MBT (adapted value) of a combination of target device values of each device set in the process of S10 can be obtained. The processes of S10 to S26 are repeatedly executed until all combinations of target device values of each device are completed. Then, the ignition timing map is created by the MBTs set for each.

In this way, in the ignition timing adjusting device 5, whether the crank angle (maximum rotational force timing at each ignition timing), which is the peak value of the rotational force Fi (θ), is the determination angle for each advanced ignition timing. By determining whether or not, the ignition timing when the angle is for determination can be determined as MBT, so that the search time for MBT can be shortened. Further, in the ignition timing matching device 5, in addition to the determination of the maximum rotational force timing, the ignition timing at which the combustion energy is the largest can be determined as the MBT by determining the magnitude relationship of the combustion energy. As a result, even when there are a plurality of ignition timings in which the maximum rotational force timing is the determination angle (for example, when there is an ignition timing region A in which the shaft torque value hardly changes as shown in FIG. 8) MBT (ignition timing on the most delayed side) can be determined from the ignition timing of.

With reference to FIGS. 5 and 6, the relationship between the maximum rotational force timing and the shaft torque of the engine 2 when the device values of EGR and TGV are changed as parameters affecting the combustion state of the engine 2 will be described. FIG. 5 is a diagram showing an example of the relationship between the maximum rotational force timing and the shaft torque when the exhaust gas is not recirculated by EGR. FIG. 6 is a diagram showing an example of the relationship between the maximum rotational force timing and the shaft torque when the exhaust gas is recirculated by EGR. In each of these examples, the engine 2 is connected to the dynamometer 3, and the engine 2 and the dynamometer 3 are controlled by the control device 4, so that the engine speeds are 2000 [rpm], 2800 [rpm], and 4000 [rpm]. The maximum rotational force timing and shaft torque were obtained for the case where the TGV was fully opened (the tumble vortex was not generated) and the case where the TGV was fully closed (the tumble vortex was generated).

The example shown in FIG. 5 is a case where the exhaust gas is not recirculated by EGR. The solid line graph indicated by the reference numeral G1 is a case where the engine speed is 2000 [rpm] and the TGV is fully open. The solid line graph indicated by the reference numeral G2 is a case where the engine speed is 2800 [rpm] and the TGV is fully open. The solid line graph indicated by the reference numeral G3 is a case where the engine speed is 4000 [rpm] and the TGV is fully open. The graph of the broken line indicated by the reference numeral G1'is a case where the engine speed is 2000 [rpm] and the TGV is fully closed. The graph of the broken line indicated by the reference numeral G2'is a case where the engine speed is 2800 [rpm] and the TGV is fully closed. The graph of the broken line indicated by the reference numeral G3'is a case where the engine speed is 4000 [rpm] and the TGV is fully closed.

According to these six graphs G1, G2, G3, G1'and G2'G3', the shaft torque is increased at the maximum rotational force time = θ2 [deg ATDC] in all the states of these six engines 2 when the exhaust gas is not recirculated. It becomes the maximum. Therefore, the maximum rotational force timing at which the shaft torque is maximum is not affected by changing the engine speed. Further, the maximum rotational force timing at which the shaft torque is maximized is not affected by the presence / absence of the tumble vortex due to the TGV.

The example shown in FIG. 6 is a case where the exhaust gas is recirculated by a predetermined amount by EGR. The solid line graph indicated by the reference numeral G4 is a case where the engine speed is 2000 [rpm] and the TGV is fully open. The solid line graph indicated by the reference numeral G5 is a case where the engine speed is 2800 [rpm] and the TGV is fully open. The solid line graph indicated by the reference numeral G6 is a case where the engine speed is 4000 [rpm] and the TGV is fully open. The graph of the broken line indicated by the reference numeral G4'is a case where the engine speed is 2000 [rpm] and the TGV is fully closed. The broken line graph indicated by the reference numeral G5'is a case where the engine speed is 2800 [rpm] and the TGV is fully closed. The graph of the broken line indicated by the reference numeral G6'is a case where the engine speed is 4000 [rpm] and the TGV is fully closed.

According to these 6 graphs G4, G5, G6, G4', G5'G6', even when the exhaust gas is recirculated, the shaft torque at the maximum rotational force time = θ2 [deg ATDC] in all the states of these 6 engines 2. Is the maximum. Therefore, even when the exhaust gas is recirculated, the maximum rotational force timing at which the shaft torque is maximized is not affected by changing the engine speed. Further, the maximum rotational force period at which the shaft torque is maximum is not affected by the presence or absence of the tumble vortex.

Further, from the examples of FIGS. 5 and 6, the maximum rotational force timing at which the shaft torque is maximized is not affected by the presence / absence of the exhaust gas recirculation due to the EGR. The shaft torque is larger when there is exhaust gas recirculation due to EGR than when there is no exhaust gas recirculation.

As described above, the maximum rotational force timing at which the shaft torque becomes maximum is not affected even if the parameters affecting the combustion state of the engine 2 (for example, the values of each device of EGR and TGV) are changed. Even if the waveform (combustion pressure waveform) of the in-cylinder pressure P (θ) shown in FIG. 3 changes due to a change in the parameter that affects the combustion state of the engine 2, the value changes according to the crank angle ( In particular, the positive value increases as the angle is retarded from the top dead center.) This is because the maximum rotational force timing at which the rotational force Fi (θ) is maximized does not change due to the action of the mechanical transmission efficiency E (θ). Therefore, by using the maximum rotational force timing, it is possible to search for an appropriate MBT (ignition timing at which the shaft torque is maximized) even if the parameters that affect the combustion state of the engine 2 change.

For example, FIG. 3 shows a change curve of the in-cylinder pressure P'(θ) when the exhaust gas is recirculated by a predetermined amount by EGR as a two-dot chain line, and the rotation calculated using this in-cylinder pressure P'(θ). The change curve of the force Fi'(θ) is shown by the alternate long and short dash line. The change curve (combustion pressure waveform) of the in-cylinder pressure P'(θ) has a slightly gentler fall than the change curve of the in-cylinder pressure P (θ) when the exhaust gas is not recirculated by EGR. It spreads a little to the retard side (combustion energy becomes a little larger). The increasing in-cylinder pressure (combustion pressure) on the retard side is appropriately reflected in the rotational force Fi'(θ) by the mechanical transmission efficiency E (θ) in which the positive value increases as the angle is retarded from top dead center. .. Therefore, the change curve of the rotational force Fi'(θ) has a slightly gentler falling edge than the change curve of the rotational force Fi (θ) when the exhaust gas is not recirculated by EGR, and is on the retard side. It's spreading a little. The maximum rotational force timing when the rotational force Fi'(θ) is maximized is the same as the maximum rotational force timing when the exhaust gas is not recirculated by EGR θ2 [deg ATDC]. Is.

According to the ignition timing matching device 5 according to the embodiment, by searching for the MBT using the maximum rotational force timing, the parameters affecting the combustion state (of each device of the engine 2) while shortening the search time of the MBT. Even if the device value) is changed, an appropriate MBT can be set. Since the MBT search time is shortened in this way, the ignition timing adaptation system 1 can reduce the man-hours for performing the MBT search by automatic operation. Further, since an appropriate MBT can be searched even when the device value of each device of the engine 2 is changed, deterioration of fuel efficiency due to the change of the MBT can be suppressed in the vehicle equipped with the engine 2.

According to the ignition timing matching device 5 according to the embodiment, the rotational force can be accurately obtained by using the in-cylinder pressure, the crank angle, and the specifications of the engine 2 according to the above (Equation 1). In particular, since this (Equation 1) includes the mechanical transmission efficiency geometrically obtained from the specifications of the engine 2 according to the crank angle, the force acting in the axial direction of the piston 2c is applied to the crankshaft 2a. It can be appropriately converted into the rotational force acting in the tangential direction of the virtual circle, and the rotational force can be obtained with high accuracy. Further, since this mechanical transmission efficiency is a coefficient that changes according to the crank angle, even if the device value of each device such as EGR changes and the combustion state changes, the change in the combustion state is appropriately applied to the rotational force. Can be reflected.

According to the ignition timing matching device 5 according to the embodiment, the combustion energy is obtained and the ignition timing at which the combustion energy is the largest is set as the MBT. Therefore, when there are a plurality of ignition timings in which the maximum rotational force timing is the determination angle. However, the MBT at which the shaft torque of the engine 2 is maximized can be determined from the plurality of ignition timings. According to the ignition timing matching device 5 according to the embodiment, the combustion energy is accurately acquired by integrating the in-cylinder pressure in a predetermined angle range using the in-cylinder pressure data (combustion pressure waveform) for each crank angle. be able to.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. For example, in the above embodiment, the control device 4 and the ignition timing matching device 5 are configured separately, but the control device 4 and the ignition timing matching device 5 may be configured as an integrated device, or the control device. 4 may be provided with a part of the processing unit (for example, the operation preparation unit 5a and the ignition timing advance angle unit 5b) of the ignition timing adjusting device 5.

In the above embodiment, the MBT is searched by not only determining the maximum rotational force timing but also determining the combustion energy and comparing the combustion energy at the ignition timings before and after, but the combustion energy is determined. Instead, the MBT may be searched only by determining the maximum rotational force timing. When there are a plurality of ignition timings at which the maximum rotational force timing is the determination angle, for example, the ignition timing on the most retarded angle side is selected and used as the MBT.

In the above embodiment, examples of parameters that affect the combustion state of the engine 2 (intake air amount, fuel injection amount, intake / exhaust valve opening / closing timing, EGR rate, presence / absence of tumble vortex) are shown, but the combustion state is shown. Other parameters that affect it include air-fuel ratio, fuel properties (octane value), amount of residual gas in the cylinder, amount of inflow from the intake valve, and shape of the intake port.

1 Ignition timing matching system 2 Engine 2a Crankshaft 2b Cylinder 2c Piston 2d Connecting rod 2e Crank arm 3 Dynamometer 4 Control device 5 Ignition timing matching device 5a Operation preparation part 5b Ignition timing advance part 5c Rotation force calculation part 5d Maximum rotational force Timing determination unit 5e Combustion energy calculation unit 5f Combustion energy determination unit 5g MBT setting unit 5h Storage unit 10 Crank angle sensor 11 Cylinder pressure sensor

Claims (7)

Ignition timing change process to change the ignition timing of the internal combustion engine,
For each ignition timing changed in the ignition timing changing step, the rotational force acting in the tangential direction of the virtual circle formed by the rotation of the crank arm of the crankshaft is acquired for each angle of the crankshaft of the internal combustion engine. Rotational force acquisition process and
The angle at which the rotational force is maximized is extracted from the rotational force data for each angle of the crankshaft acquired in the rotational force acquisition step, and it is determined whether or not the extracted angle is the preset maximum rotational force timing. The process of determining the maximum rotational force to be performed and
An ignition timing setting step for setting the ignition timing at which the torque of the internal combustion engine is maximized according to the ignition timing when the maximum rotational force timing is determined in the rotational force maximum timing determination step.
Only including,
In the rotational force acquisition step, the in-cylinder pressure of the cylinder of the internal combustion engine is detected for each angle of the crankshaft, and the force acting in the axial direction of the piston of the cylinder obtained from the detected in-cylinder pressure and the internal combustion engine. An ignition timing matching method, characterized in that the rotational force for each angle of the crankshaft is obtained by the mechanical transmission efficiency of transmitting the axial force of the piston in the tangential direction of the virtual circle obtained from the specifications of the above. .. In the rotational force acquisition step, the rotational force is set to Fi (θ) [N], the angle of the crankshaft is set to θ [deg], the in-cylinder pressure is set to P (θ) [kPa], and the cross-sectional area of the piston is set. Is A [mm ² ], the length of the connecting rod is l [mm], and the crank radius of the crankshaft is r [mm], the rotational force Fi (θ) is calculated by (Equation 1). The ignition timing adaptation method according to claim 1 , wherein the ignition timing is adapted.

A combustion energy acquisition step of detecting the in-cylinder pressure of the cylinder of the internal combustion engine for each angle of the crankshaft and acquiring the combustion energy in the cylinder using the data of the in-cylinder pressure for each angle of the detected crankshaft.
A storage step for storing the combustion energy acquired in the combustion energy acquisition step, and a storage step for storing the combustion energy acquired in the combustion energy acquisition step.
A combustion energy determination step for determining the magnitude relationship between the combustion energy acquired in the combustion energy acquisition step and the combustion energy stored in the storage process at the previous ignition timing, and
Including
In the ignition timing setting step, the combustion energy is the largest among the ignition timings when the ignition timing is determined to be the preset maximum rotational force timing in the rotational force maximum timing determination step based on the determination result in the combustion energy determination step. The ignition timing adaptation method according to claim 1 or 2 , wherein the ignition timing is set as the ignition timing at which the torque of the internal combustion engine is maximized. Ignition timing change process to change the ignition timing of the internal combustion engine,
For each ignition timing changed in the ignition timing changing step, the rotational force acting in the tangential direction of the virtual circle formed by the rotation of the crank arm of the crankshaft is acquired for each angle of the crankshaft of the internal combustion engine. Rotational force acquisition process and
The angle at which the rotational force is maximized is extracted from the rotational force data for each angle of the crankshaft acquired in the rotational force acquisition step, and it is determined whether or not the extracted angle is the preset maximum rotational force timing. The process of determining the maximum rotational force to be performed and
An ignition timing setting step for setting the ignition timing at which the torque of the internal combustion engine is maximized according to the ignition timing when the maximum rotational force timing is determined in the rotational force maximum timing determination step.
A combustion energy acquisition step of detecting the in-cylinder pressure of the cylinder of the internal combustion engine for each angle of the crankshaft and acquiring the combustion energy in the cylinder using the data of the in-cylinder pressure for each angle of the detected crankshaft.
A storage step for storing the combustion energy acquired in the combustion energy acquisition step, and a storage step for storing the combustion energy acquired in the combustion energy acquisition step.
A combustion energy determination step for determining the magnitude relationship between the combustion energy acquired in the combustion energy acquisition step and the combustion energy stored in the storage process at the previous ignition timing, and
Including
In the ignition timing setting step, the combustion energy is the largest among the ignition timings when the ignition timing is determined to be the preset maximum rotational force timing in the rotational force maximum timing determination step based on the determination result in the combustion energy determination step. setting fire timing adaptation method points you characterized in that the ignition timing as the ignition timing which the torque becomes the maximum of the internal combustion engine. The combustion energy acquisition step, using the data of the in-cylinder pressure for each angle of the crankshaft, the cylinder pressure is integrated by a predetermined angular range, according to claim 3, the integral value, characterized in that said combustion energy Or the ignition timing adaptation method according to 4. Crank angle detection means for detecting the angle of the crankshaft of an internal combustion engine,
An ignition timing changing means for changing the ignition timing of the internal combustion engine, and
For each ignition timing changed by the ignition timing changing means, the rotational force acting in the tangential direction of the virtual circle formed by the rotation of the crank arm of the crankshaft is acquired for each angle of the crankshaft of the internal combustion engine. Rotational force acquisition means and
The angle at which the rotational force is maximized is extracted from the rotational force data for each angle of the crankshaft acquired by the rotational force acquisition means, and it is determined whether or not the extracted angle is the preset maximum rotational force timing. Means for determining the maximum timing of rotational force and
Ignition timing setting means for setting the ignition timing at which the torque of the internal combustion engine is maximized according to the ignition timing when the rotational force maximum timing is determined by the rotational force maximum timing determination means.
A cylinder pressure detecting means for detecting the cylinder pressure of the cylinder of the internal combustion engine is provided.
The rotational force acquisition means is obtained from the force acting in the axial direction of the piston of the cylinder obtained from the in-cylinder pressure detected by the in-cylinder pressure detecting means for each angle of the crankshaft and the specifications of the internal combustion engine. An ignition timing matching device, characterized in that the rotational force for each angle of the crankshaft is acquired by the mechanical transmission efficiency of transmitting the axial force of the piston in the tangential direction of the virtual circle. Combustion energy acquisition means for acquiring combustion energy in the cylinder using data of the in-cylinder pressure detected by the in-cylinder pressure detecting means for each angle of the crankshaft.
A storage means for storing the combustion energy acquired by the combustion energy acquisition means, and a storage means for storing the combustion energy.
Combustion energy determination means for determining the magnitude relationship between the combustion energy acquired by the combustion energy acquisition means and the combustion energy stored in the storage means at the previous ignition timing, and
With
The ignition timing setting means has the largest combustion energy among the ignition timings when the ignition timing is determined to be the maximum rotational force timing preset by the rotational force maximum timing determination means based on the determination result in the combustion energy determination means. The ignition timing conforming device according to claim 6 , wherein the ignition timing is set as the ignition timing at which the torque of the internal combustion engine is maximized.

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