Fire detection system

Abstract

To provide a misfire determination system capable of improving accuracy of a misfire determination.SOLUTION: A misfire determination system 1 determines misfire of an engine 2 connected to a motor 3 via a damper 5. The misfire determination system includes: an engine control section 11 having an axial torque calculation section 111 that calculates axial torque applied to an output shaft of the engine 2, a misfire determination section 112 that determines whether misfire has occurred in the engine; a motor control section 12 having an output torque calculation section that calculates output torque of the damper 5; and a communication determination section 122 that determines whether a communication status between the engine control section 11 and the motor control section 12 is normal. When the communication determination section 122 determines that the communication status between the engine control section 11 and the motor control section 12 is normal, the misfire determination section 112 determines whether misfire has occurred in the engine 2 on the basis of a difference between the axial torque applied to the output shaft of the engine 2 and the output torque of the damper.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a fire detection system.

Background Art

[0002] Patent Document 1 describes a vehicle control device that performs misfire determination of an engine. The vehicle control device described in Patent Document 1 calculates the output torque of the engine based on the rotational speed of the output shafts of the engine and the motor generator and the output torque of the motor. Then, based on the calculated output torque of the engine, misfire determination of the engine is executed.

[0003] In the vehicle control device described in Patent Document 1, an ENG-ECU that controls the engine acquires the rotational speed of the output shaft of the engine, and an MG-ECU that controls the motor generator acquires the rotational speed of the output shaft of the motor generator and the output torque of the motor.

[0004] The ENG-ECU and the MG-ECU described in Patent Document 1 are synchronized by acquiring an NE (Number of Engine speed) signal output from a sensor attached to the output shaft of the engine. The NE signal is output from a sensor attached to the output shaft of the engine to the ENG-ECU and is output from the ENG-ECU to the MG-ECU.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the vehicle control device described in Patent Document 1, in order to execute misfire determination, it is necessary to synchronize the ENG-ECU and the MG-ECU with high precision. Therefore, when an abnormality occurs in the communication between the ENG-ECU and the MG-ECU and the ENG-ECU and the MG-ECU cannot be synchronized with sufficient accuracy, there has been a problem that misjudgment of engine misfire occurs.

[0007] The present disclosure has been made to solve such problems, and an object thereof is to provide a misfire determination system capable of improving the accuracy of misfire determination.

Means for Solving the Problems

[0008] The misfire determination system according to the present disclosure is a misfire determination system that determines misfire of an engine connected to a motor via a damper, an engine control unit having a shaft torque calculation unit that calculates a shaft torque applied to the output shaft of the engine based on an angular acceleration of the output shaft of the engine, and a misfire determination unit that determines whether the engine is misfiring; a motor control unit having an output torque calculation unit that calculates an output torque of the damper based on an angular acceleration of the output shaft of the motor and the output torque of the motor; a communication determination unit that determines whether the communication status between the engine control unit and the motor control unit is normal; When the communication determination unit determines that the communication status between the engine control unit and the motor control unit is normal, the misfire determination unit calculates the difference between the shaft torque applied to the output shaft of the engine calculated by the shaft torque calculation unit and the output torque of the damper calculated by the output torque calculation unit as the output torque of the engine, and determines whether the engine is misfiring based on the output torque of the engine. It is a misfire determination system.

[0009] According to such a configuration, misjudgment of misfire due to communication abnormality between the engine control unit and the motor control unit can be suppressed. As a result, the accuracy of misfire determination can be improved.

Effects of the Invention

[0010] According to the present disclosure, a misfire determination system capable of improving the accuracy of misfire determination can be provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0012] (First Embodiment) <Configuration of Misfire Determination System> Hereinafter, a first embodiment according to the present disclosure will be described in detail with reference to the drawings. First, the configuration of the misfire determination system according to the present embodiment will be described in detail. FIG. 1 is a block diagram for explaining the configuration of the misfire determination system according to the first embodiment.

[0013] The misfire determination system 1 is a misfire determination system that determines the misfire of an engine connected to a motor via a damper. That is, the misfire determination system 1 is typically a misfire determination system that determines whether or not the engine mounted on a vehicle using an engine and a motor as drive power sources, that is, a hybrid vehicle, is misfiring.

[0014] As shown in FIG. 1, the misfire determination system 1 according to the present embodiment is connected to a motor 3 and an engine 2 connected to the motor 3 via a damper 5. The misfire determination system 1 according to the present embodiment determines whether or not the engine 2 is misfiring.

[0015] The misfire determination system 1 according to the first embodiment includes an engine control unit 11 and a motor control unit 12, and the engine control unit 11 and the motor control unit 12 are connected by a CAN communication line CL and a direct communication line DL.

[0016] The engine 2 is an engine connected to the motor 3 via the damper 5. More specifically, the engine 2 is an engine connected to the motor 3 via the damper 5 and the power transmission mechanism 4. The engine 2 burns fossil fuel based on the control from the engine control unit 11 and outputs torque.

[0017] The engine 2 has an output shaft that outputs torque, and a sensor for detecting the rotational speed of the output shaft is attached to the output shaft. The sensor outputs information regarding the detected rotational speed of the output shaft of the engine 2 to the engine control unit 11 as an NE (Number of Engine speed) signal. Note that the NE signal output by the engine 2 is also output directly to the motor control unit 12 via the communication line DL.

[0018] The output shaft of the engine 2 outputs the output torque of the engine 2 to the damper 5. Also, the output shaft of the engine 2 receives the output torque of the damper 5. That is, the torque applied to the output shaft of the engine 2 can be expressed as the sum of the output torque of the engine 2 and the output torque of the damper 5. Here, the following mathematical formula 1 holds.

[0019]

Equation

[0020] However, T 1 eng represents the shaft torque applied to the output shaft of the engine 2, and T 0 eng represents the output torque of the engine 2, and T dmp represents the absolute value of the output torque of the damper 5.

[0021] In addition, the engine 2 has a camshaft for opening and closing the valves of the cylinders, and a sensor for detecting the rotational speed of the camshaft is attached to the camshaft. The sensor outputs information regarding the detected rotational speed of the output shaft of the engine 2 to the engine control unit 11 as a cam signal. Note that the cam signal output by the engine 2 is also output directly to the motor control unit 12 via the communication line DL.

[0022] The power transmission mechanism 4 connects the motor 3 and the damper 5. The power transmission mechanism 4 is a mechanism for adjusting and outputting the output torque of the motor 3 at an appropriate rotational speed, torque, or rotational direction, and may be, for example, a planetary gear.

[0023] The power transmission mechanism 4 according to the present embodiment is a planetary gear, and it is assumed that the output shaft of the motor 3 is connected to the sun gear shaft and the damper 5 is connected to the carrier shaft. Also, assume that the ratio of the number of teeth of the ring gear to the number of teeth of the sun gear is ρ.

[0024] The damper 5 is a device that connects the engine 2 and the motor 3, and is a device attached to suppress the torsional vibration of the output shafts of the engine 2 and the motor 3. The damper 5 outputs an output torque according to the torsional angle between the output shaft of the engine 2 and the output shaft of the motor 3 via the power transmission mechanism 4. More specifically, the damper 5 outputs a larger output torque to the output shaft of the engine 2 and the output shaft of the motor 3 as the torsional angle between the output shaft of the engine 2 and the output shaft of the motor 3 via the power transmission mechanism 4 becomes larger.

[0025] The motor 3 is a motor connected to the engine 2 via the damper 5. More specifically, the motor 3 is connected to the engine 2 via the damper 5 and the power transmission mechanism 4. The motor 3 converts the electric power supplied from an in-vehicle battery (not shown) based on the control from the motor control unit 12 into torque. The motor 3 outputs information regarding the magnitude of the output torque to the motor control unit 12.

[0026] The motor 3 has an output shaft for outputting torque, and a sensor for detecting the rotational speed of the output shaft is attached to the output shaft. The sensor outputs the detected angular velocity of the output shaft of the motor 3 to the motor control unit 12.

[0027] The output shaft of the motor 3 outputs the output torque of the motor 3 to the damper 5 via the power transmission mechanism 4. Also, the output shaft of the motor 3 receives the output torque of the damper 5 via the power transmission mechanism 4. That is, the torque applied to the output shaft of the motor 3 can be expressed as the sum of the output torque of the motor 3 and the output torque of the damper 5. Here, the following mathematical formula 2 holds.

[0028]

Equation

[0029] However, T 1 mg represents the shaft torque applied to the output shaft of the motor 3, and T 0 mg represents the output torque of the motor 3. Note that ρ / (1 + ρ) is a coefficient for reflecting the torque conversion by the power transmission mechanism 4.

[0030] The engine control unit 11 is a device for controlling the operation of the engine 2. The engine control unit 11 may include, for example, an arithmetic unit such as a CPU (Central Processing Unit) (not shown), and a storage unit such as a RAM (Random Access Memory) and a ROM (Read Only Memory) in which programs, data, etc. for controlling the engine 2 are stored. That is, the engine control unit 11 may have the function of a computer and control the engine 2 based on the above program.

[0031] Therefore, each functional block constituting the engine control unit 11 shown in FIG. 1 can be configured by the above CPU, storage unit, other circuits, etc. in terms of hardware, and can be realized by a program for controlling the engine 2 stored in the storage unit, etc. in terms of software. That is, the engine control unit 11 can be realized in various forms by hardware, software, or a combination of both.

[0032] The engine control unit 11 includes a shaft torque calculation unit 111 that calculates the shaft torque applied to the output shaft of the engine 2 based on the angular acceleration of the output shaft of the engine 2, and a misfire determination unit 112 that determines whether or not the engine 2 is misfiring. The engine control unit 11 is connected to the motor control unit 12 via the CAN communication line CL and the direct communication line DL.

[0033] Here, the CAN communication line CL is a communication line for executing CAN (Control Area Network) communication between the engine control unit 11 and the motor control unit 12 using the CAN protocol. The direct communication line DL is a communication line branched from a communication line for transmitting the NE signal and the cam signal from the engine 2 to the engine control unit 11, and is a communication line for transmitting the NE signal and the cam signal output from the engine 2 to the motor control unit 12. In this embodiment, the direct communication line DL branches inside the engine control unit 11, but the direct communication line DL may branch outside the engine control unit 11.

[0034] The motor control unit 12 is a device for controlling the operation of the motor 3. The motor control unit 12 may include, for example, an arithmetic unit such as a CPU (not shown) and a storage unit such as a RAM and a ROM in which a program and data for controlling the motor 3 are stored. That is, the motor control unit 12 has the function of a computer and may control the motor 3 based on the above program.

[0035] Therefore, each functional block that constitutes the motor control unit 12 shown in FIG. 1 can be configured by the above CPU, storage unit, other circuits, etc. in terms of hardware, and can be realized by a program for controlling the motor 3 stored in the storage unit, etc. in terms of software. That is, the motor control unit 12 can be realized in various forms by hardware, software, or a combination of both.

[0036] The motor control unit 12 includes an output torque calculation unit 121 that calculates the output torque of the damper 5 based on the angular acceleration of the output shaft of the motor 3 and the output torque of the motor 3. Further, the motor control unit 12 according to the present embodiment includes a communication determination unit 122 that determines whether the communication status between the engine control unit 11 and the motor control unit 12 is normal.

[0037] The shaft torque calculation unit 111 calculates the shaft torque applied to the output shaft of the engine 2 based on the angular acceleration of the output shaft of the engine 2. More specifically, the shaft torque calculation unit 111 calculates the angular acceleration of the output shaft of the engine 2 based on the NE signal and the cam signal acquired from the engine 2, and calculates the shaft torque applied to the output shaft of the engine 2 based on the angular acceleration. Here, the shaft torque calculation unit 111 may calculate the shaft torque applied to the output shaft of the engine 2 based on the following mathematical formula 3.

[0038]

Equation

[0039] However, T 1 eng represents the shaft torque applied to the output shaft of the engine 2, I eng represents the inertial mass of the output shaft of the engine 2, ω eng represents the angular velocity of the output shaft of the engine 2, and t represents time. Note that, as the inertial mass of the output shaft of the engine 2, a constant stored in the storage unit of the engine control unit 11 (not shown) may be used.

[0040] The shaft torque calculation unit 111 outputs information regarding the shaft torque applied to the output shaft of the engine 2 to the misfire determination unit 112. Here, the information regarding the shaft torque applied to the output shaft of the engine 2 includes at least information regarding the magnitude of the calculated shaft torque and information regarding the timing at which the calculated shaft torque is applied to the output shaft of the engine 2.

[0041] The information regarding the timing at which the calculated shaft torque is applied to the output shaft of the engine 2 may be, for example, information that associates the magnitude of the calculated shaft torque with the rotation angle of the output shaft of the engine 2. The shaft torque calculation unit 111 creates information regarding the timing at which the shaft torque is calculated based on the NE signal and the cam signal acquired from the engine 2.

[0042] The output torque calculation unit 121 calculates the output torque of the damper 5 based on the angular acceleration of the output shaft of the motor 3 and the output torque of the motor 3. More specifically, the output torque calculation unit 121 first calculates the angular acceleration of the output shaft of the motor 3 based on the angular velocity of the output shaft of the motor 3 acquired from the motor 3, and calculates the shaft torque applied to the output shaft of the engine 2 based on the angular acceleration. Here, the output torque calculation unit 121 may calculate the shaft torque applied to the output shaft of the motor 3 based on the following formula 4.

[0043]

Equation

[0044] However, I mg represents the inertial mass of the output shaft of the motor 3, and ω mg represents the angular velocity of the output shaft of the motor 3. Note that, as the inertial mass of the output shaft of the motor 3, a constant stored in a storage unit of the motor control unit 12 (not shown) may be used.

[0045] Then, the output torque calculation unit 121 calculates the output torque of the damper 5 based on the calculated shaft torque applied to the output shaft of the motor 3 and the output torque of the motor 3 acquired from the motor 3. Here, the output torque calculation unit 121 may calculate the output torque of the damper 5 based on the following mathematical formula 5 obtained from mathematical formulas 2 and 4.

[0046]

Equation

[0047] The output torque calculation unit 121 transmits information regarding the output torque of the damper 5 to the engine control unit 11 via the CAN communication line CL. Here, the information regarding the output torque of the damper includes at least information regarding the magnitude of the calculated output torque and information regarding the timing at which the calculated output torque is output from the damper 5.

[0048] The information regarding the timing at which the calculated output torque is output from the damper 5 is, for example, information that associates the magnitude of the calculated output torque with the rotation angle of the output shaft of the engine 2. The output torque calculation unit 121 creates information regarding the timing at which the calculated output torque is output from the damper 5 based on the NE signal and the cam signal acquired directly from the engine control unit 11 via the communication line DL.

[0049] The communication determination unit 122 determines whether the communication status between the engine control unit 11 and the motor control unit 12 is normal. More specifically, the communication determination unit 122 determines whether the NE signal and the cam signal are normally transmitted from the engine control unit 11 to the motor control unit 12.

[0050] First, the communication determination unit 122 determines whether the engine control unit 11 and the motor control unit 12 can communicate normally via the CAN communication line CL. That is, the communication determination unit 122 determines whether the CAN communication between the engine control unit 11 and the motor control unit 12 is normal. When the communication determination unit 122 determines that the CAN communication is abnormal, it may notify the misfire determination unit 112 not to execute the misfire determination. Further, when the communication determination unit 122 determines that the CAN communication is abnormal, it may notify the driver of a warning.

[0051] When the communication determination unit 122 determines that the CAN communication is normal, it determines whether the engine control unit 11 and the motor control unit 12 can communicate normally directly via the communication line DL. That is, the communication determination unit 122 determines whether the direct line communication between the engine control unit 11 and the motor control unit 12 is normal.

[0052] For example, the communication determination unit 122 compares the NE signal and the cam signal transmitted via the CAN communication line CL with the NE signal and the cam signal transmitted via the direct communication line DL, and determines that the direct line communication is normal when there is no contradiction between the two.

[0053] In this way, by the communication determination unit 122 determining whether the communication status between the engine control unit 11 and the motor control unit 12 is normal, the reliability of the NE signal and the cam signal transmitted from the engine control unit 11 to the motor control unit 12 can be improved. As described above, the information regarding the timing when the calculated shaft torque is applied to the output shaft of the engine 2 and the information regarding the timing when the calculated output torque is output from the damper 5 are created based on the NE signal and the cam signal. Therefore, by improving the reliability of the NE signal and the cam signal, the reliability of the information regarding both timings is improved. As a result, the accuracy of the misfire determination is improved.

[0054] The communication determination unit 122 outputs the determination result to the output torque calculation unit 121 and the misfire determination unit 112. Note that the communication determination unit 122 may output the determination result to the misfire determination unit 112 via the output torque calculation unit 121.

[0055] The misfire determination unit 112 determines whether the engine is misfiring. More specifically, when the communication determination unit 122 determines that the communication status between the engine control unit 11 and the motor control unit 12 is normal, the misfire determination unit 112 calculates the difference between the shaft torque applied to the output shaft of the engine 2 calculated by the shaft torque calculation unit 111 and the output torque of the damper 5 calculated by the output torque calculation unit 121 as the output torque of the engine 2, and determines whether the engine 2 is misfiring based on the output torque of the engine 2.

[0056] That is, first, the misfire determination unit 112 obtains from the communication determination unit 122 the determination result as to whether the communication status between the engine control unit 11 and the motor control unit 12 is normal. When both the communication executed via the CAN communication line CL and the communication executed via the direct communication line DL are normal, the misfire determination unit 112 obtains information regarding the shaft torque applied to the output shaft of the engine 2 from the shaft torque calculation unit 111 and obtains information regarding the output torque of the damper 5 from the output torque calculation unit 121. Then, the misfire determination unit 112 calculates the output torque of the engine based on the following formula 6 obtained by transforming formula 1.

[0057]

Equation

[0058] Here, the misfire determination unit 112 refers to the information regarding the timing when the calculated shaft torque is applied to the output shaft of the engine 2 and the information regarding the timing when the calculated output torque is output from the damper 5. Then, at the same timing, the magnitude of the shaft torque applied to the output shaft of the engine 2 and the magnitude of the output torque output from the damper 5 are substituted into formula 6 to calculate the output torque of the engine 2 at that timing.

[0059] The misfire determination unit 112 performs a misfire determination of the engine 2 based on the calculated output torque of the engine 2. For example, the misfire determination unit 112 may perform misfire determination of the engine 2 by comparing the magnitude of the output torque of the engine 2 at the ignition timing of the cylinders of the engine 2 that is the target of misfire determination with the magnitude of the output torque of the engine 2 at the timing after a predetermined time has elapsed since the ignition of the cylinders.

[0060] When the communication determination unit 122 determines that the CAN communication is normal and the direct wire communication is abnormal, the misfire determination unit 112 may calculate the angular velocity of the output shaft of the engine 2 from which the torsional component by the damper 5 has been excluded, and perform misfire determination of the engine 2 based on the angular velocity. In this case, first, the misfire determination unit 112 acquires information regarding the angular velocity of the output shaft of the engine 2 from the shaft torque calculation unit 111, and acquires information regarding the angular velocity of the output shaft of the motor 3 via the CAN communication line CL from the output torque calculation unit 121. Then, based on the following formula 7, the torsional component by the damper 5 is calculated, and based on formula 8, the angular velocity of the output shaft of the engine 2 from which the torsional component by the damper 5 has been excluded is calculated.

[0061]

Equation

Equation

[0062] However, ω dmp is the torsional component by the damper 5, K dmp is the spring stiffness value of the damper 5, and ω 0 eng is the angular velocity of the output shaft of the engine 2 from which the torsional component by the damper 5 has been excluded.

[0063] The misfire determination unit 112 performs misfire determination of the engine 2 based on the calculated angular velocity of the output shaft of the engine 2 from which the torsional component by the damper 5 has been excluded. For example, the misfire determination unit 112 may execute misfire determination of the engine 2 by comparing the magnitude of the calculated angular velocity at the ignition timing of the cylinder of the engine 2 that is the target of misfire determination with the magnitude of the calculated angular velocity at a timing after a predetermined time has elapsed since the ignition of the cylinder.

[0064] As described above, when the misfire determination unit 112 executes misfire determination of the engine 2 based on the angular velocity of the output shaft of the engine 2 from which the torsional component by the damper 5 has been eliminated, information regarding the angular velocity of the output shaft of the motor 3 is transmitted from the motor control unit 12 to the engine control unit 11. Information regarding the angular velocity of the output shaft of the motor 3 is transmitted to the engine control unit 11 without going through the arithmetic processing by the motor control unit 12, unlike the information regarding the output torque of the damper 5, and thus has a high immediacy of information as compared with the information regarding the output torque of the damper 5. Therefore, the information regarding the angular velocity of the output shaft of the motor 3 only needs to include at least information regarding the magnitude of the angular velocity of the output shaft of the motor 3. That is, when the misfire determination unit 112 executes misfire determination of the engine 2 based on the angular velocity of the output shaft of the engine 2 from which the torsional component by the damper 5 has been eliminated, the misfire determination can be executed even if the engine control unit 11 and the motor control unit 12 are not synchronized with high reliability by the NE signal and the cam signal.

[0065] However, when the misfire determination unit 112 executes misfire determination of the engine 2 based on the angular velocity of the output shaft of the engine 2 from which the torsional component by the damper 5 has been eliminated, it is necessary to use the spring rigidity value of the damper 5, which is generally difficult to maintain high estimation accuracy, and thus the accuracy of misfire determination decreases. Also, it is necessary to consider the information transmission time by CAN communication, which also causes a decrease in the accuracy of misfire determination.

[0066] That is, when the engine control unit 11 and the motor control unit 12 are synchronized with high reliability, the misfire determination unit 112 according to the present embodiment executes misfire determination using a more accurate method. When the misfire determination unit 112 according to the present embodiment determines that the engine control unit 11 and the motor control unit 12 are not synchronized with high reliability, it performs misfire determination using a method that is executable even in such a situation although the accuracy is relatively low.

[0067] <Operation of the misfire determination system> Subsequently, the operation of the misfire determination system, that is, the misfire determination method according to the first embodiment will be described in detail. FIG. 2 is a flowchart for explaining the operation of the misfire determination system according to the first embodiment. In the following description, FIG. 1 will be referred to as appropriate.

[0068] First, the communication determination unit 122 determines whether the CAN communication is normal (step S1). More specifically, it determines whether the engine control unit 11 and the motor control unit 12 can communicate normally via the CAN communication line CL. When the CAN communication is not normal (step S1 NO), the misfire determination system 1 ends a series of operations. That is, when the CAN communication is not normal (step S1 NO), the misfire determination system 1 does not execute misfire determination. Note that when the CAN communication is not normal (step S1 NO), the misfire determination system 1 may notify the driver of a warning.

[0069] When the CAN communication is normal (step S1 YES), the communication determination unit 122 determines whether the direct wire communication is normal (step S2). That is, the communication determination unit 122 determines whether the engine control unit 11 is transmitting the NE signal and the cam signal normally to the motor control unit 12 via the direct communication line DL.

[0070] When the direct wire communication is normal (step S2 YES), the shaft torque calculation unit 111 calculates the shaft torque applied to the output shaft of the engine 2 (step S3), and the output torque calculation unit 121 calculates the output torque of the damper 5 (step S4). More specifically, the shaft torque calculation unit 111 calculates the shaft torque applied to the output shaft of the engine 2 using Equation 3. Then, the output torque calculation unit 121 calculates the output torque of the damper 5 using Equation 5. Note that the execution order of step S3 and step S4 may be reversed. Also, step S3 and step S4 may be executed in parallel.

[0071] Next, the misfire determination unit 112 calculates the output torque of the engine (step S5). More specifically, first, the misfire determination unit 112 acquires information regarding the shaft torque applied to the output shaft of the engine 2 from the shaft torque calculation unit 111, and acquires information regarding the output torque of the damper 5 from the output torque calculation unit 121. Then, based on Equation 6, the output torque of the engine is calculated.

[0072] Finally, the misfire determination unit 112 determines whether the engine is misfiring (step S6), and the misfire determination system 1 ends a series of operations. More specifically, based on the output torque of the engine 2 calculated in step S5, the misfire determination unit 112 determines whether the engine is misfiring, and the misfire determination system 1 ends a series of operations.

[0073] When the direct line communication is not normal (step S2 NO), the misfire determination unit 112 acquires the angular velocities of the output shafts of the engine 2 and the motor 3 (step S7). More specifically, the misfire determination unit 112 acquires the angular velocity of the output shaft of the engine 2 from the shaft torque calculation unit 111, and acquires the angular velocity of the output shaft of the motor 3 from the output torque calculation unit 121 via the CAN communication line CL.

[0074] Next, the misfire determination unit 112 calculates the torsional vibration component of the damper 5 (step S8), and calculates the torsional vibration component of the output shaft of the engine 2 from which the torsional vibration component of the damper 5 has been excluded (step S9). More specifically, the misfire determination unit 112 calculates the torsional vibration component of the damper 5 based on Equation 7, and calculates the angular velocity of the output shaft of the engine 2 from which the torsional vibration component of the damper 5 has been excluded based on Equation 8.

[0075] Finally, the misfire determination unit 112 determines whether the engine is misfiring (step S6), and the misfire determination system 1 ends a series of operations. More specifically, based on the angular velocity of the output shaft of the engine 2 from which the torsional vibration component of the damper 5 calculated in step 9 has been excluded, the misfire determination unit 112 determines whether the engine is misfiring, and the misfire determination system 1 ends a series of operations.

[0076] As described above, the misfire determination system 1 according to the present embodiment executes misfire determination based on the determination result regarding the communication status by the communication determination unit 122. With such a configuration, the misfire determination system 1 according to the present embodiment can improve the accuracy of misfire determination of the engine 2.

[0077] (Other embodiments) In the first embodiment, the motor control unit 12 includes the communication determination unit 122, but the engine control unit 11 may be configured to include the communication determination unit 122. In the case of such a configuration, for example, the engine control unit 11 transmits a confirmation signal to the motor control unit 12, and the motor control unit returns a response signal. Then, for example, by measuring the time from when the engine control unit 11 transmits the confirmation signal until the response signal is received, the communication determination unit 122 can determine whether the communication status between the engine control unit 11 and the motor control unit 12 is normal.

[0078] Although the present invention has been described in accordance with the above embodiments, the present invention is not limited only to the configurations of the above embodiments, and of course includes various modifications, corrections, and combinations that those skilled in the art can make within the scope of the invention of the claims of the present patent application.

Explanation of reference numerals

[0079] 1 Misfire determination system 2 Engine 3 Motor 4 Power transmission mechanism 5 Damper 11 Engine control unit 12 Motor control unit 111 Axial torque calculation unit 112 Misfire determination unit 121 Output torque calculation unit 122 Communication determination unit CL CAN communication line DL Direct communication line

Claims

【Claim 1】 A misfire determination system for determining misfires in an engine connected to a motor via a damper comprising: an engine control unit having a shaft torque calculation unit that calculates a shaft torque applied to the output shaft of the engine based on the angular acceleration of the output shaft of the engine, and a misfire determination unit that determines whether the engine is misfiring; a motor control unit having an output torque calculation unit that calculates the output torque of the damper based on the angular acceleration of the output shaft of the motor and the output torque of the motor; a communication determination unit that determines whether the communication status between the engine control unit and the motor control unit is normal; The misfire determination unit: when the communication determination unit determines that the communication status between the engine control unit and the motor control unit is normal, calculates the difference between the shaft torque applied to the output shaft of the engine calculated by the shaft torque calculation unit and the output torque of the damper calculated by the output torque calculation unit as the output torque of the engine, and determines whether the engine is misfiring based on the output torque of the engine; when the communication determination unit determines that the communication status between the engine control unit and the motor control unit is not normal, calculates the angular velocity of the output shaft of the engine with the torsional component eliminated by the damper based on the angular velocity of the output shaft of the engine, the angular acceleration of the output shaft of the motor, and the spring stiffness value of the damper, and determines whether the engine is misfiring based on the angular velocity of the output shaft of the engine. A misfire determination system.

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