JP2008175174A - Internal-combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal-combustion engine which smoothly starts as a whole by suppressing inconvenience generated when each cylinder group makes cylinder determination individually. <P>SOLUTION: The internal-combustion engine 1 has a plurality of cylinder groups RB and LB, in which a cam angle sensor 25 to sense the rotating position of a cam shaft 8 is installed on each cylinder 2R, 2L, and the cylinder groups RB and LB are furnished with crank angle sensors 15R and 15L to sense the rotating position of a crank shaft 6 and control devices 30L and 30R, respectively, and at starting, these control devices perform cylinder determination, wherein the control devices 30L and 30R are set communicable with each other and exchange the information concerning the cylinder judgement. As each of the control devices executing cylinder judgement individually make sure of the determining situation of the other control device(s), the starting characteristic of the internal-combustion engine is enhanced by executing the cylinder determination quickly and certainly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine having a plurality of cylinder groups. More specifically, the present invention relates to an internal combustion engine configured to provide a control device for each cylinder group and perform cylinder discrimination for each cylinder group.

  Generally, an internal combustion engine (engine) mounted on a vehicle has a plurality of cylinders. In order to drive the internal combustion engine smoothly, it is important to perform fuel injection and ignition with good timing according to the stroke of each cylinder. Therefore, it is required to quickly and accurately determine the cylinder when starting the engine. When cylinder discrimination is delayed or inaccurate, a situation occurs such as injecting fuel in vain. As a result, startability, exhaust emission, etc. deteriorate and start-up failure becomes a problem.

  Therefore, for example, Patent Document 1 discloses a cylinder discrimination device for an engine in which cylinder discrimination is performed based on the number of crank angle signals and a cylinder discrimination signal after the start of cranking. In this device, every time a cylinder discrimination signal is output after cranking starts, the output number count value of the crank angle signal so far is held. Among these held count values, those whose difference from the count value at the cylinder discrimination timing is within a certain value can be discriminated because the cylinder discrimination signal is output during the predetermined crank angle period. As a result, the cylinder can be discriminated by detecting the number of cylinder discrimination signals output during a predetermined crank angle period. In this way, cylinder discrimination can be performed after cranking is started, and quick cylinder discrimination can be performed to improve startability and exhaust emission.

JP 2001-342887 A

  Some internal combustion engines, such as a V-type engine, have a plurality of cylinders (cylinder groups) arranged in left and right banks. In such a V-type engine, it is conceivable that a control device (ECU: Electronic Control Unit) is arranged for each bank and cylinder discrimination is performed independently. Since the cylinder groups in the left and right banks are symmetrical, it is possible to perform cylinder discrimination by arranging an ECU for each bank. However, even if the cylinder discrimination is executed for each bank, there is one crankshaft (output shaft). For example, in the case of a 12-cylinder V-type engine, the right bank belongs to the first, third,..., 11 odd-numbered cylinders, and the left bank belongs to the second, fourth,. It is supposed to be the number cylinder.

  Therefore, if the cylinder discrimination is performed for each bank and fuel injection or ignition is performed independently, the drive timing may differ (shift) between the banks. As a result, an output difference occurs between the left and right banks, and the above-mentioned starting failure becomes a problem.

  Therefore, an object of the present invention is to provide an internal combustion engine that can suppress a disadvantage that occurs when each cylinder group individually performs cylinder discrimination and can perform a smooth start as a whole.

  The object is to provide a cam angle sensor that has a plurality of cylinder groups, detects the rotational position of the camshaft in each cylinder, and detects the rotational position of the crankshaft for each cylinder group, and a control device. And the control device performs cylinder discrimination at the time of starting, and the control devices are set to be communicable with each other and communicate information regarding cylinder discrimination with each other. .

  According to the present invention, since each control device that performs cylinder discrimination individually can check the judgment status of other control devices, fuel is not injected into the cylinder by adjusting the discrepancy of the cylinder discrimination timing or contradictory results. It is possible to prevent the occurrence of a situation (so-called injection omission). Therefore, it is possible to provide an internal combustion engine in which cylinder discrimination is performed quickly and reliably and startability is improved.

  Then, one control device that has completed cylinder discrimination may transmit the information to the other control device before cylinder discrimination, and the other control device may perform cylinder discrimination by using the received information. . In this case, since the control device with a delay uses the cylinder discrimination result of the other control device, the entire internal combustion engine can be discriminated quickly and without missing.

  In addition, the order of cylinder discrimination between the cylinder groups may be set. In this case, even if it takes a little time to start the first cylinder discrimination, smooth cylinder discrimination can be realized thereafter.

  Further, the crank angle sensor detects rotation by detecting a missing tooth portion formed on an outer peripheral portion of a crank position rotor fixed to a crankshaft, and a cylinder group whose cylinder discrimination is slower than other cylinder groups In addition, when there is a cylinder that is difficult to discriminate due to a change in the output of the cam angle sensor, the crank angle sensor is removed after the change in the output of the cam angle sensor and before the cylinder discrimination of the cylinder. An internal combustion engine in which the position of the crank angle sensor is set so as to detect the tooth portion may be used.

  ADVANTAGE OF THE INVENTION According to this invention, the internal combustion engine which can suppress the problem which generate | occur | produces when each cylinder group performs cylinder discrimination | determination separately, and can perform a smooth start as a whole can be provided.

  Hereinafter, an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an internal combustion engine 1 according to a first embodiment. The internal combustion engine 1 is a so-called V-type engine, and a left bank LB and a right bank RB are formed. A plurality of cylinders 2 (three in this example) are arranged in each of the left bank LB and the right bank RB to form a cylinder group. The members belonging to the right bank RB are the first cylinder 2R-1, the third cylinder 2R-3, and the fifth cylinder 2R-5. Also belonging to the left bank LB are the second cylinder 2L-2, the fourth cylinder 2L-4, and the sixth cylinder 2L-6. Each bank is individually provided with intake passages 3R, 3L. The parts common to the left and right banks are distinguished by attaching the symbol L to the configuration belonging to the left bank and the component R belonging to the right bank.

  As shown in FIG. 1, the left and right banks are symmetrical with each other, and the cylinder structure in each bank is the same. Therefore, the first cylinder 2R-1 of the right bank RB will be described as a representative structure. The first cylinder 2R-1 is disposed in the cylinder 4 so that the piston 5 can move up and down. A connecting rod (not shown) is connected to the lower side of the piston 5. The reciprocating motion of the piston 5 is converted into the rotational motion of the crankshaft 6 shown in the lower part of FIG. 1 via the connecting rod. The same applies to the pistons of the other cylinders, and all the pistons are connected to one crankshaft 6 serving as an output shaft.

  A crank position rotor 10 for detecting the rotational position is fixed to the end of the crankshaft 6. A tooth portion 11 having a plurality of teeth arranged at predetermined intervals is formed on the outer peripheral portion of the crank position rotor 10, and a missing tooth portion 12 having no teeth is formed in a part thereof. The crank position rotor 10 is made of, for example, a ferromagnetic member, and is provided with a crank angle sensor 15 having a built-in electromagnetic pickup coil. The voltage generated by the crank angle sensor 15 by the electromagnetic induction action changes when the missing tooth portion 12 passes. Therefore, the rotation angle (crank angle) of the crankshaft 6 can be detected based on the output of the crank angle sensor 15.

  As shown in FIG. 1, the crank angle sensor 15 is provided as a left crank angle sensor 15L and a right crank angle sensor 15R for each of the left and right banks. The left crank angle sensor 15L and the right crank angle sensor 15R are arranged so as to be shifted from the crankshaft center by a predetermined angle α (for example, 120 degrees in the case of 6 cylinders).

  Further, a cam position rotor 20 is fixed to the end of the camshaft 8 that defines the opening / closing operation of the intake valve 7 in the first cylinder 2R-1. The cam position rotor 20 is also provided with a configuration for detecting the rotational position. Teeth are also formed at predetermined intervals on the outer periphery of the cam position rotor 20. A cam angle sensor 25 is disposed opposite to the cam position rotor 20. Therefore, the rotation angle (cam angle) of the camshaft 8 can be detected based on the output of the cam angle sensor 25. As shown in FIG. 1, the cam angle sensor 25 is provided in each cylinder, and a total of six cam angle sensors 25 are provided in the internal combustion engine. Note that the structure of the intake valve 7, the camshaft 8, the cam position rotor 20, and the cam angle sensor 25 described here is common to each cylinder, but for simplification of description, the distinction between the cylinder and the left and right (R, L) is made. Omitted.

  Furthermore, the internal combustion engine 1 is provided with an electronic control unit (hereinafter referred to as ECU) that controls the driving of each bank. This ECU also has an ECU 30R and an ECU 30L for each of the left and right banks.

  The ECU 30R of the right bank includes the output of the cam angle sensor 25 of the cylinders (first cylinder 2R-1, third cylinder 2R-3 and fifth cylinder 2R-5) belonging to the right bank RB and the right crank angle sensor 15R. Output is supplied. Further, the ECU 30R is supplied with outputs of various sensors (not shown) (accelerator opening sensor, engine temperature sensor, etc.) provided in the internal combustion engine 1 and based on these outputs. Control the drive. In addition, the ECU 30R includes a storage device such as a ROM (not shown) that stores a series of programs (such as a program related to cylinder discrimination) relating to the start control of the internal combustion engine 1 and a RAM that provides a processing area.

  The same applies to the left bank ECU 30L. The output of the cam angle sensor 25 and the left crank angle sensor of the cylinders (second cylinder 2L-2, fourth cylinder 2L-4, and sixth cylinder 2L-6) belonging to the left bank LB. A 15 L output is supplied. The ECU 30L controls the driving of the left bank LB based on these outputs.

  As described above, the internal combustion engine 1 includes the ECU 30L and the ECU 30R in the left and right banks, so that a quick cylinder discrimination can be performed for the cylinder group in each bank. If the control is performed so that the left and right banks LB and RB are controlled independently, the control logic of the internal combustion engine 1 can be simplified. Thereby, it is expected that the internal combustion engine 1 as a whole performs early cylinder discrimination and enhances startability.

  By the way, it is one output shaft (namely, crankshaft 6) that is driven by the left and right banks. It is the second cylinder 2L-2 in the left bank LB, not the same right bank (third cylinder 2R-3), that is desired to be driven smoothly and continuously to the first cylinder 2R-1 in the right bank RB. Here, if each of the ECU 30L and the ECU 30R executes the cylinder discrimination completely independently, the following problem may occur.

  That is, the internal combustion engine 1 has mechanical and electrical component errors and assembly errors, and is also affected by disturbances. Therefore, it is assumed that the timing of cylinder discrimination executed by the ECU 30L and the ECU 30R is different (shifted). And when the cylinder discrimination timing between banks exceeds the allowable range, the original left and right alternate ignition is realized as in the first cylinder 2R-1, the second cylinder 2L-2,. I can't. For example, the second cylinder 2L-2 may misfire. In such a situation, the driving force cannot be smoothly transmitted to the crankshaft and vibrations are generated, causing a start failure.

  In view of this, the internal combustion engine 1 of the present embodiment incorporates a configuration in which the ECU 30L and the ECU 30R in the left and right banks can perform cylinder discrimination without timing deviation in response to the above problem. Hereinafter, this point will be described.

  The left and right ECUs 30L and 30R are connected to each other via a communication bus 32. The ECUs 30L and 30R are set to perform inter-bank communication using a CAN (Controller Area Network) that is proposed as a communication system for in-vehicle LAN (Local Area Network), for example, and is standardized as an international standard protocol.

  FIG. 2 is a diagram schematically showing the relationship between the left ECU 30L and the right ECU 30R of the internal combustion engine 1. As shown in FIG. The left and right ECUs 30L and 30R are originally set to individually perform cylinder discrimination and control fuel injection and ignition. However, as described above, it is assumed that a situation occurs in which the cylinder discrimination timing is different. Therefore, the left ECU 30L and the right ECU 30R communicate information related to cylinder discrimination with the above-described CAN to achieve cooperation in cylinder discrimination. The cylinder discrimination information can include information based on the crank angle sensor 15 and the cam angle sensor 25 in each bank. For example, information on the crank counter is provided from one ECU that has completed cylinder discrimination to the other ECU before or during cylinder discrimination. Thereby, the ECU on the bank side with the discrimination delay can accelerate the cylinder discrimination. In addition, the ECU that has received the information at this time can achieve smooth cylinder discrimination as a whole by avoiding a decision that contradicts the information received during the cylinder discrimination. As a result, the cylinder discrimination can be executed quickly and reliably as the internal combustion engine 1 as a whole, so that the startability can be improved.

  With reference to the figure, a specific description will be given of how to deal with a case where the timing of cylinder discrimination differs greatly between the left and right banks. FIG. 3 is a schematic diagram for explaining an example of control executed when the cylinder discrimination timings of the left and right banks are different (shifted) and the cylinder discrimination of the right bank RB is completed first. As shown in FIG. 3, when the cylinder discrimination by the ECU 30R in the right bank RB is completed, the cylinder discrimination (original cylinder discrimination) by the ECU 30L in the left bank LB is delayed. In this case, the right ECU 30R transmits to the ECU 30L on the left side of its own cylinder discrimination information via the communication system CAN. Receiving this, the left ECU 30L executes cylinder discrimination of the left bank LB based on this information.

  At this time, the cylinder discrimination information of the right bank RB cannot be used as it is on the left bank LB side. However, for example, the first cylinder 2R-1 in the right bank RB and the second cylinder 2L-2 in the left bank LB are set with a difference of 60 degrees around the crankshaft. Therefore, by using the cylinder discrimination information of the right bank RB, the delay of the cylinder discrimination of the left bank LB can be eliminated and the discrimination can be accelerated. Thus, by obtaining information on the crank counter from the right bank RB, the left bank LB can perform cylinder discrimination earlier than the original cylinder discrimination.

  In the internal combustion engine 1 described above, information is transmitted from one ECU that has completed cylinder discrimination at an early stage to the other ECU that has a delay. Based on this, since the other ECU executes cylinder discrimination, the time required for cylinder discrimination can be shortened for the entire internal combustion engine. Further, since the cylinder discrimination delay uses the cylinder discrimination information of the ECU on the opposite side, the cylinder discrimination can be executed in an accurate order. Therefore, it is possible to prevent the occurrence of cylinders that do not perform fuel injection (injection omission) or the like and execute fuel injection and ignition alternately in order. Therefore, the internal combustion engine 1 of the present embodiment can improve the startability.

  Next, an internal combustion engine to which the control device according to the second embodiment is applied will be described. The hardware configuration of the apparatus according to the second embodiment is the same as that of the first embodiment, and only the control content executed by the left and right ECUs when performing cylinder discrimination is different. Therefore, description will be made by using the reference numerals of the internal combustion engine 1 of the first embodiment shown in FIG.

  In the second embodiment, the bank order for cylinder discrimination is set in advance. For example, the program is set so that priority is given to cylinder discrimination of the right bank RB to which the first cylinder 2R-1 belongs. Therefore, when the cylinder discrimination of the left bank LB on the opposite side is completed first, the left ECU 30L waits until the cylinder discrimination of the right bank RB becomes possible. FIG. 4 is a diagram illustrating the second embodiment, and is a schematic diagram illustrating a control example that is executed when the cylinder discrimination timings of the left and right banks are different as in FIG. 3 in the first embodiment.

  Left and right ECU 30L. When the preparation for cylinder discrimination is completed, 30R communicates with CAN to check the cylinder discrimination state on the opposite side with reference to a crank counter or the like. Here, when the preparation of the right ECU 30R is early, or when the preparation is completed simultaneously on the left and right, the right ECU 30R is prioritized and the cylinder discrimination is performed.

  On the other hand, when the left ECU 30L is ready for cylinder discrimination and the right ECU 30R is not ready for cylinder discrimination, the left ECU 30L waits for 360 CA (360 ° around the crankshaft), for example, and always waits. Priority is given to cylinder discrimination by the right ECU 30R.

  In the second embodiment, the starting time may be a little longer, but cylinder discrimination is always performed in order with priority given to the cylinder discrimination of the right ECU 30R. It can be started smoothly. Therefore, also in the case of the second embodiment, the startability of the internal combustion engine can be improved as a result.

  Furthermore, an internal combustion engine to which the control device according to the third embodiment is applied will be described. In the case of the third embodiment as well, the basic hardware configuration is the same as that of the first embodiment, and the control executed by the left and right ECUs when performing cylinder discrimination differs. Therefore, the same reference numerals as those shown in FIG. However, in the case of the internal combustion engine of the first embodiment, the left and right banks have 3 cylinders and a total of 6 cylinders, but the internal combustion engine of the present embodiment 3 is assumed to have 5 banks in each bank and 10 cylinders in total.

  This will be described with reference to FIG. FIG. 5 is a timing chart collectively showing the outputs of the left crank angle sensor 15L, the right crank angle sensor 15R, and the cam angle sensor 25 provided in the internal combustion engine (see FIG. 1). In FIG. 5, the upper side shows the right bank RB and the lower side shows the left bank LB.

  The internal combustion engine of the first embodiment described above has 6 cylinders, and the left crank angle sensor 15L and the right crank angle sensor 15R are arranged with a predetermined angle α of 120 degrees with respect to the center of the crankshaft (see FIG. 1). ). Two revolutions (720 degrees) of the crankshaft is one cycle, and 120 degrees is calculated by dividing (dividing) by 6 of the total number of cylinders. Normally, the predetermined angle α formed by the left crank angle sensor 15L and the right crank angle sensor 15R is set by dividing 720 degrees by the total number of cylinders. The internal combustion engine of the third embodiment has 10 cylinders. Therefore, in principle, the left crank angle sensor 15L and the right crank angle sensor 15R have a predetermined angle α of 72 degrees. Therefore, as shown in the uppermost part of FIG. 5, for example, a position of 108 degrees shifted by 72 degrees from 36 degrees of the right crank angle sensor 15R corresponds to a position of 36 degrees of the right crank angle sensor 15R. (See 36 at the bottom of FIG. 5).

  Normally, cylinder discrimination is performed with reference to the outputs from the left crank angle sensor 15L and right crank angle sensor 15R arranged as described above and the signal of the cam angle sensor 25 arranged in each cylinder. The

  However, as indicated by an arrow AR in FIG. 5, the signal falls from the cam angle sensor 25 from the right bank RB, which should originally match, and the signal from the cam angle sensor 25 from the left bank LB. May occur. More specifically, an output signal is issued from the cam angle sensor 25 earlier than the uneven structure (hard) of the right cam position rotor, and further, the cam angle sensor is issued later than the uneven structure (hard) of the left cam position rotor. 25 may output an output signal. When such a situation occurs, an unconfirmed area with hatching indicated by an arrow AR occurs. As a result, fuel injection may be lost. FIG. 5 illustrates a case where a missing fuel injection occurs in No. 9 (# 9) fuel injection. As shown in FIG. 5, the unconfirmed area occurs as described above when the signals of the cam angle sensors in the right and left banks are switched at the same time. Often occurs when the peak is from the valley on the slow signal side.

  When it is confirmed that injection failure occurs under the above conditions, it can be dealt with by changing the set position of the crank angle sensor 15. Specifically, when it is assumed that there is a possibility that the ninth cylinder cannot be discriminated as described above, this can be dealt with by shifting the timing of detecting the missing tooth portion 12 of the crank position rotor 10 from the principle position FP. Specifically, the right crank angle sensor is to detect the missing tooth portion 12 after the timing at which cylinder discrimination becomes difficult due to the output change of the signal of the cam angle sensor and before cylinder discrimination of the ninth cylinder. Change the position of 15R. In this way, even when the edges of the cam angle sensor signals in the right bank are switched almost simultaneously, cylinder discrimination can be made reliably and injection failure can be prevented. Therefore, also in the case of the present embodiment, it is possible to more reliably prevent the occurrence of injection omission and to start the internal combustion engine smoothly.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

1 is a view showing an internal combustion engine according to Embodiment 1. FIG. It is the figure which showed typically the relationship between left ECU and right ECU of the internal combustion engine of an Example. It is a schematic diagram for demonstrating the example of control performed when the cylinder discrimination | determination time of a right-and-left bank differs and the cylinder discrimination | determination of the right bank RB is completed previously. FIG. 10 is a diagram illustrating the second embodiment, and is a schematic diagram illustrating a control example that is executed when cylinder discrimination timings of the left and right banks are different. 6 is a timing chart collectively showing sensor outputs of an internal combustion engine according to a third embodiment.

Explanation of symbols

1 Internal combustion engine 2R-1, 2R-3, 2R-5 Right cylinder 2L-2, 2L-4, 2L-6 Left cylinder 3R, 3L Intake passage 4 Cylinder 5 Piston 6 Crankshaft 8 Camshaft 15 (15R, 15L) Crank angle sensor 25 Cam angle sensor 30R ECU (control device for right cylinder group)
30L ECU (control device for left cylinder group)
32 Bus for communication system LB Left bank RB Right bank

Claims (4)

Each cylinder group is provided with a cam angle sensor that detects the rotational position of the camshaft, and includes a crank angle sensor that detects the rotational position of the crankshaft and a control device for each cylinder group. Sometimes the control device is an internal combustion engine for each cylinder discrimination,
An internal combustion engine characterized in that the control devices are set to communicate with each other and communicate information relating to cylinder discrimination. The one control device that has completed cylinder discrimination transmits the information to the other control device before cylinder discrimination, and the other control device performs cylinder discrimination by using the received information. Item 6. The internal combustion engine according to Item 1. The internal combustion engine according to claim 1, wherein the order of cylinder discrimination between the cylinder groups is preset. The crank angle sensor detects rotation by detecting a missing tooth portion formed on an outer peripheral portion of a crank position rotor fixed to a crankshaft,
When there is a cylinder in which cylinder discrimination is slower than other cylinder groups and cylinder discrimination becomes difficult due to a change in the output of the cam angle sensor,
The position of the crank angle sensor is set so that the crank angle sensor detects the missing tooth portion after the output change of the cam angle sensor and before cylinder discrimination of the cylinder. Item 6. The internal combustion engine according to Item 1.

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