Drive control device

Abstract

Drive control device (1;11) comprising: an energy-generating motor (4;13) which is connected to a drive machine (2) and is configured to generate energy as a result of being driven by the drive machine (2), and a control unit (6;14) which is configured to control the driving by the drive machine (2) based on an actual torque value as a torque generated by the power generation motor (4;13) and a torque command value output to the power generation motor (4;13), wherein the control unit (6;14) is configured to compare the actual torque value and the torque command value, and to control the driving by the drive machine (2) when a difference between the actual torque value and the torque command value is greater than a predetermined threshold (τ th ) is, wherein the control unit (6;14) is configured to determine that an abnormality exists in a state of energy generation when the difference between the actual torque value and the torque command value is greater than the predetermined threshold, and wherein the control unit (6;14) is configured to control the driving by the drive machine (2) when the abnormality is determined, characterized by the fact that the control unit (6;14) is configured to perform a control to stop fuel injected into the drive motor (2), or the drive machine (2) has a throttle valve in an air intake system, and the control unit (6;14) is configured to perform control to maintain a constant opening of the throttle valve.

Description

[0001] This invention relates to a drive control device which can prevent deterioration of exhaust emission or deterioration of fuel consumption.

[0002] A vehicle is known to which a mechanism (hereinafter referred to as a “power generation system”) is mounted which can convert an output of a prime mover into electrical energy.

[0003] A motor generator (also called “MG”) is used in the power generation system.

[0004] For example, a “power generation engine” for generating power, a “locomotion engine” (also called a “drive engine”) for performing locomotion, etc. are known as a motor generator (e.g., JP 2008-92 708 A).

[0005] In order to obtain a desired power generation in the power generation system, a load (hereinafter referred to as "power generation load") is applied to the prime mover to drive the prime mover, so that the power generation motor can receive a rotational motion obtained by driving the prime mover to generate power.

[0006] In this regard, when the power generation motor cannot generate a desired torque, the power generation load applied to the prime mover becomes much larger or smaller than a target load, so that the rotation speed of the prime mover cannot follow a target rotation speed.

[0007] Thus, there is a possibility that a disadvantage may occur, namely that exhaust emission performance or fuel consumption performance may deteriorate.

[0008] Incidentally, the target rotation speed here refers to the engine rotation speed at which exhaust emission performance or fuel consumption performance is excellent. The load applied to the engine to achieve the target rotation speed is referred to as the "target load."

[0009] DE 10 2004 044 507 A1 discloses a method and a device for operating a vehicle drive, comprising at least one internal combustion engine and at least one electric motor mechanically coupled to the internal combustion engine, as well as an energy storage device operatively connected to the electric motor and / or the internal combustion engine. It is proposed that the internal combustion engine and the electric motor generate a requested drive target torque at least approximately together, wherein a requested optimal target torque of the internal combustion engine is limited to an optimized minimum torque above a minimum internal combustion engine torque or an optimized maximum torque below a maximum internal combustion engine torque, and / or a rate of change of the optimal target torque of the internal combustion engine is limited.

[0010] DE 195 36 038 A1 describes a method and a device for controlling an internal combustion engine as a drive unit of a motor vehicle, in which the maximum permissible torque or the maximum permissible power is determined and if this limit value is exceeded by a calculated actual torque or power value, at least one error reaction is initiated.

[0011] DE 10 2006 037 124 A1 discloses a control system for a drive unit of a hybrid vehicle with an internal combustion engine and an electric motor, comprising a control unit assigned to the drive unit, which has a functional level and a functional monitoring level, and a power output stage for controlling the drive unit or actuators or sensors assigned to the drive unit. The control system uses, on the one hand, the actual torque value of the internal combustion engine and that of the electric motor, and, on the other hand, the supplied torque command value of the internal combustion engine and that of the electric motor for the purposes of fault detection.For this purpose, a sum of the supplied torque command values ​​of the internal combustion engine and the electric motor and a sum of the actual torque values ​​of the internal combustion engine and the electric motor are calculated. These sums are then compared with a permissible torque. Exceeding the permissible torque is interpreted as an error, and a shutdown signal is sent to the internal combustion engine.

[0012] JP 2002-95102 A addresses the problem of how to cope in a case where a motor-generator has a problem such that it fails while operating as a generator in a hybrid vehicle equipped with a prime mover and a motor-generator. It is proposed that when the motor-generator receives a regenerative command torque from a motor-generator regeneration controller and the motor-generator is operating as a generator, the regenerative power of the motor-generator is calculated from the regenerative command torque of the motor-generator and the motor-generator speed, and compared with the measured value of the regenerative power actually generated by the motor-generator. If the difference exceeds a predetermined threshold, the driver is warned.

[0013] US 2011 / 0 276 213 A1 discloses a control device for a hybrid vehicle that causes the hybrid vehicle to travel in limp-home mode using drive power from a prime mover when either a motor or a battery cannot be used for traveling. The prime mover of the hybrid vehicle includes a device for recirculating a portion of exhaust gases into a vehicle intake system (EGR device). Even if an operating condition of the prime mover satisfies a prescribed EGR permission condition for the operation of the EGR device, the control device prohibits the operation of the EGR device during limp-home mode traveling if an abnormality detection flag is set to 1.

[0014] Therefore, the object of this invention is to control driving of an engine with respect to making a determination that an abnormality has occurred in a power generation system, thereby preventing deterioration of output of exhaust gas or deterioration of fuel consumption.

[0015] This invention comprises the features of claim 1, in particular a power generation motor which is connected to a prime mover and generates power due to driving by the prime mover, and a control unit which controls the driving by the prime mover based on an actual torque value as a torque generated by the power generation motor and a torque command value output to the power generation motor.

[0016] According to this invention, the driving of the prime mover is controlled to determine that an abnormality has occurred in the power generation system. Therefore, a fault that leads to deterioration of exhaust emissions and deterioration of fuel consumption can be detected, making it possible to prevent the deterioration of exhaust emissions and deterioration of fuel consumption.

[0017] In addition, with respect to determining that an abnormality has occurred in the power generation system, controls such as fuel reduction, constant throttle control, and engine output restriction are performed so that exhaust emission deterioration can be minimized. In addition, a situation such as the vehicle traveling while exhaust emission deterioration occurs can be prevented. Fig. 1 is a flowchart of abnormality determination control performed by a drive control device (Embodiment 1). Fig. 2 is a schematic configuration diagram of the drive control device (Embodiment 1). Fig. 3 is a schematic configuration diagram of another drive control device (Embodiment 2).

[0018] Embodiments of this invention will be described below in detail with reference to the drawings.

[0019] Fig. 1 and Fig. 2 show an embodiment of this invention.

[0020] In Fig. 2, reference numeral 1 denotes a drive control device of a series hybrid vehicle.

[0021] As in Fig. 2, a power generation system of the drive control device 1 is configured to include a prime mover 2, a drive motor (also denoted by “MG1”) 3, a power generation motor (also denoted by “MG2”) 4 that is connected to the prime mover 2 and generates power due to driving by the prime mover 2, a high-voltage battery (also denoted by “B”) 5, and a control unit (also denoted by “CC”) 6 that integrally controls the vehicle.

[0022] On this occasion, the control unit 6 is configured to control the driving by the prime mover 2 based on an actual torque value as a torque generated by the power generation motor 4 and a torque command value output to the power generation motor 4.

[0023] In particular, the control unit 6 determines an energy to be generated based on a state of charge of the high-voltage battery 5, an energy consumption of the drive motor 3, etc.

[0024] The control unit 6 determines a target engine rotation speed and a torque command value that can maximize (improve) exhaust emission performance or fuel performance of the engine 2 while providing the power to be generated. Then, the control unit 6 outputs a torque command to output the torque command value to the engine 2.

[0025] On this occasion, the torque command value is set based on the target rotation speed and the torque with which the prime mover 2 can be operated most efficiently.

[0026] Incidentally, the target rotation speed and torque at which the prime mover 2 can be operated most efficiently aim, for example, at an engine rotation speed and torque at which exhaust emission performance and fuel consumption performance can be excellent.

[0027] In addition, the target rotation speed can follow the power generation motor 4 by the control unit 6 changing the torque command value.

[0028] However, if a fault occurs or the driving is restricted by heat, the power generation motor 4 may not follow the torque command issued by the control unit 6, so the engine rotation speed may not follow the target rotation speed. Therefore, there is a possibility that exhaust emissions or fuel consumption may deteriorate.

[0029] To solve this problem, the control unit 6 compares the actual torque value and the torque command value. If the difference between the actual torque value and the torque command value is greater than a predetermined threshold value τth, the control unit 6 controls the driving of the prime mover 2.

[0030] Specifically, the control unit 6 acquires an absolute value of the difference between the actual torque value and the torque command value, and compares the absolute value and the predetermined threshold value τth with each other when the actual torque value and the torque command value are compared with each other.

[0031] In addition, the control unit 6 determines that an abnormality exists in the power generation state when the difference between the actual torque value and the torque command value is greater than the predetermined threshold value τth. When the abnormality is determined, the control unit 6 controls the driving by the prime mover 2.

[0032] Furthermore, the control unit 6 is configured to provide a function as a determination counter C, which counts the number of times an abnormality has been determined. When the determination counter C exceeds a preset upper limit Cth, the control unit 6 confirms that an abnormality has occurred and controls the driving of the prime mover 2.

[0033] In addition, as the control of driving by the engine 2 performed by the control unit 6, the control unit 6 specifically performs the control of stopping a fuel injected into the engine 2 (fuel reduction).

[0034] In addition, the control unit 6 performs control to keep constant an opening of a throttle valve (not shown) provided in an air intake system of the engine 2 (constant throttle control).

[0035] In addition, the control unit 6 performs control for adjusting the torque of the prime mover 2 to be close to the target rotation speed of the prime mover 2 (prime mover output restriction).

[0036] Only one of these controls (the fuel cut, the constant throttle control, and the engine output restriction) may be executed, or these controls may be executed in combination.

[0037] The drive control device 1 can perform the following functions. (1) Recording the actual torque value

[0038] An actual torque value is calculated from an output current, etc., of the power generation motor 4.

[0039] The calculation of the actual torque value may be performed by the power generation motor 4, or may be performed by the control unit 6. (2) Determination of abnormality based on torque comparison

[0040] The control unit 6 compares a torque command value output to the power generation motor 4 and the calculated actual torque value. If the comparison reveals that a difference between the torque command value and the actual torque value is greater than a predetermined threshold value τth, the control unit 6 determines that an abnormality has occurred in the power generation system. (3) Control when an abnormality is determined

[0041] When the abnormality in the power generation system is determined, the control unit 6 controls the driving of the prime mover 2.

[0042] Fig. 1 is a flowchart of abnormality determination control performed by the drive control device 1.

[0043] When a control program of the drive control device 1 starts (101), the control program proceeds to a process (102) where: “Determination counter C→0”

[0044] The process (102) is a step of resetting the determination counter C, which counts the frequency of abnormality determination, to “0 (zero)”.

[0045] After the process (102), the control program proceeds to a determination (103) as to whether or not an abnormality determination execution condition has been established.

[0046] When the determination (103) as to whether or not an abnormality determination execution condition has been established is NO, the control program repeatedly executes the determination (103) until the determination (103) is YES.

[0047] If the determination (103) as to whether an abnormality determination execution condition has been established or not is YES, the control program proceeds to a determination (104): Torque command value - actual torque value l > τth

[0048] The determination (104) is a step of comparing the actual torque value and the torque command value and making a determination as to whether or not an absolute value of a difference between the actual torque value and the torque command value is greater than a predetermined threshold value τth.

[0049] If the determination (104) is NO, that is, the absolute value of the difference between the actual torque and the torque command value is smaller than the predetermined threshold value τth, the control program returns to the process (102).

[0050] If the determination (104) is YES, that is, the absolute value of the difference between the actual torque value and the torque command value is greater than the predetermined threshold value τth, the control program proceeds to a process (105) wherein: “Determination counter C→C+1”

[0051] The process (105) is a step of adding “1” to the last determination counter C to set a new determination counter C so as to measure the frequency of determination that an abnormality has occurred.

[0052] Then the control program proceeds to a determination (106): C>Cth

[0053] The determination (106) is a step of comparing the measured value of the determination counter C, which counts the number of times of determination that an abnormality has occurred, with a determination counter upper limit Cth which has been set in advance.

[0054] If determination (106) is NO, the measured value of the determination counter C does not exceed the determination counter upper limit Cth. Accordingly, the occurrence of an abnormality is not confirmed. Then, the control program returns to determination (103).

[0055] If the determination (106) is YES, the measured value of the determination counter C exceeds the determination counter upper limit Cth. Accordingly, the occurrence of an abnormality is confirmed (107).

[0056] When the occurrence of an abnormality is confirmed (107), the driving is controlled by the driving machine 2 (108).

[0057] At least one of the following processes relating to the drive control of the prime mover 2 is performed. (1) Control for stopping the fuel injected into the engine 2 (fuel reduction) (2) Control for keeping the opening of the throttle valve constant (constant throttle control) (3) Control for setting the torque of the prime mover 2 close to the target rotation speed (prime mover output restriction)

[0058] Thus, the control unit 6 of the drive control device 1 controls the driving of the engine 2 based on an actual torque value as a torque generated by the power generation motor 4 and a torque command value output to the power generation motor 4, so that the control unit 6 can detect a fault that leads to deterioration in exhaust emission and deterioration in fuel consumption. Accordingly, the control unit 6 can prevent the deterioration in exhaust emission and deterioration in fuel consumption.

[0059] In addition, the torque command value is set based on a target rotation speed and torque at which the engine 2 can be operated most efficiently. Accordingly, the engine 2 can be operated at an engine rotation speed at which exhaust emission performance and fuel consumption performance are excellent, which contributes to preventing deterioration in exhaust emission and deterioration in fuel consumption.

[0060] In addition, the control unit 6 compares the actual torque value and the torque command value with each other. When the difference between the actual torque value and the torque command value is greater than a predetermined threshold τth, the control unit 6 can perform fuel cut, constant throttle control, engine output restriction, etc., to minimize exhaust emission deterioration.

[0061] In addition, the control unit 6 determines that there is an abnormality in the power generation state when the difference between the actual torque value and the torque command value is greater than the predetermined threshold value τth.

[0062] Fig. 3 shows embodiment 2 of the invention.

[0063] In Embodiment 2, the components that serve the same functions as those shown in Embodiment 1 are denoted by the same reference numerals, respectively.

[0064] Although the drive control device 1 of the series hybrid vehicle has been described in Embodiment 1, a drive control device 11 of a parallel hybrid vehicle will be described in Embodiment 2.

[0065] As in Fig. 3, a power generation system of the drive control device 11 includes a prime mover 2, a transmission (also denoted by "TM") 12, an assist motor (also denoted by "MG") 13 connected to the prime mover 2 and the transmission 12, a high-voltage battery (also denoted by "B") 5, and a control unit (also denoted by "CC") 14 that integrally controls the vehicle.

[0066] The control unit 14 determines the power to be generated based on a charge level of the high-voltage battery 5 or an acceleration / deceleration request from a user. The control unit 14 also determines a target engine rotation speed and torque at which exhaust emission performance or fuel consumption performance of the engine 2 is excellent while providing the power to be generated. The control unit 14 then outputs a torque command to the engine 2.

[0067] The prime mover rotation speed can follow the target rotation speed by combining the gear ratio performed by the transmission 2 and the torque change performed by the assist motor 13.

[0068] When the assist motor 13 cannot follow a torque command value output by the control unit 14 in the system of the drive control device 11 of the parallel hybrid vehicle, the engine rotation speed cannot follow the target rotation speed. Accordingly, control similar to the abnormality determination control described in Embodiment 1 is effective.

[0069] In addition, in the configuration of Embodiment 2, the engine rotation speed can be controlled only by the transmission 12. Accordingly, the vehicle can travel in a state close to a normal state while minimizing the reduction in exhaust emission performance and the reduction in fuel consumption performance when the control mode is changed in the case where an abnormality has been confirmed to occur.

[0070] Thus, a failure that leads to deterioration of exhaust emission and deterioration of fuel consumption can be detected, so that the deterioration of exhaust emission and deterioration of fuel consumption can be prevented. List of reference symbols 1 drive control device 2 drive machine 3 Drive motor (also referred to as “MG1”) 4 Power generation engine (also referred to as “MG2”) 5 High-voltage battery (also designated by “B”) 6 Control unit (also referred to as “CC”)

Claims

[1] Drive control device (1;11), comprising: a power generation motor (4; 13) connected to a prime mover (2) and configured to generate power due to driving by the prime mover (2), and a control unit (6; 14) configured to control the driving by the prime mover (2) based on an actual torque value as a torque generated by the power generation motor (4; 13) and a torque command value output to the power generation motor (4; 13), wherein the control unit (6; 14) is configured to compare the actual torque value and the torque command value with each other, and to control the driving by the prime mover (2) when a difference between the actual torque value and the torque command value is greater than a predetermined threshold value (τ th ) is, wherein the control unit (6; 14) is configured to determine that there is an abnormality in a state of power generation when the difference between the actual torque value and the torque command value is greater than the predetermined threshold value, and wherein the control unit (6; 14) is configured to control the driving by the prime mover (2) when the abnormality is determined, characterized by , that the control unit (6; 14) is configured to perform a control for stopping fuel injected into the engine (2), or the prime mover (2) has a throttle valve in an air intake system, and the control unit (6;14) is configured to perform control for keeping an opening of the throttle valve constant. [2] The drive control device (1; 11) according to claim 1, wherein the control unit (6; 14) is configured to perform control for adjusting the torque of the prime mover (2) so that it is close to a target rotation speed of the prime mover (2). [3] A drive control device (1; 11) according to claim 1 or 2, wherein the torque command value is set based on a target rotation speed and a torque with which the drive machine (2) can be operated most efficiently.

Images