JP2015107765A - Vehicle failure determination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle failure determination device capable of determining failure of a second MG rotation number sensor without adding new calculation means or the like.SOLUTION: The failure determination device is applied to a hybrid vehicle in which a correlation speed expression is established between first MG rotation number Ng, second MG rotation number Nm, and engine rotation number Ne, and executes rotation number sensor failure determination processing. In the second MG rotation number evaluation step (S02, S03), when the second MG rotation number sensor value Nm_sns and a second MG rotation number calculation value calculated by using the correlation speed expression from engine rotation number Ne_sns and first MG rotation number Ng_sns are not equal (S03:NO), and in an engine torque evaluation step (S05, S06), when engine target torque Te_tgt and engine indirect estimation torque Te_est_mg1 calculated by multiplying proportional constant to the torque of the first MG are equal (S06:YES), it is determined that the second MG rotation number sensor is in a provisional failure state (S07).

Description

  The present invention relates to a failure determination apparatus for a hybrid vehicle including a power split mechanism.

  Conventionally, a first motor generator, a second motor generator (hereinafter referred to as “MG”) and an engine are provided as driving force sources, and their rotation shafts are connected to a power split mechanism constituted by a planetary gear mechanism. Accordingly, there is known a hybrid vehicle in which the first MG, the second MG, and the engine speed are correlated with each other. In this type of hybrid vehicle, the drive control is executed based on the detection value detected by the rotation speed sensor (including the rotation speed or rotation angle sensor) of each driving force source. May decrease or become uncontrollable.

  Therefore, for example, the electric vehicle drive device disclosed in Patent Document 1 includes a rotation speed calculation unit that calculates the rotation speed of an MG with three or more different calculation methods for one MG, and calculates with a certain calculation method. If the calculated value is different from the values calculated by the other two calculation methods, it is determined that the different value is abnormal.

  The power output apparatus for a hybrid vehicle disclosed in Patent Document 2 determines whether the first MG itself is malfunctioning or the power splitter is malfunctioning when the first MG rotation abnormality is detected. Specifically, when the rotation speed of the first MG does not increase to a predetermined value at the time of starting the engine, it is determined that the first MG is locked abnormally (see S114 in FIG. 5 and FIG. 7). On the other hand, when the first MG, the second MG, and the engine speed are all within the predetermined values, it is determined that the power split mechanism has a seizure between the gears (see S136 in FIG. 6 and FIG. 10).

JP 2003-143707 A JP 2006-052833 A

Since the apparatus of Patent Document 1 calculates the rotation speed with three or more calculation methods for one MG, the system becomes complicated and an increase in cost is assumed. Further, the apparatus of Patent Document 2 cannot detect an abnormality of the second MG rotational speed sensor.
The present invention was created in view of the above points, and an object of the present invention is to provide a vehicle failure determination device that determines failure of the second MG rotation speed sensor without adding new calculation means or the like. There is. The failure refers to a functional failure that detects a rotational speed different from the actual rotational speed.

The present invention is a vehicle failure determination device applied to a hybrid vehicle having the following configuration.
The hybrid vehicle includes a first MG, a second MG, an engine, a power split mechanism, a first MG rotation speed sensor, a second MG rotation speed sensor, and an engine rotation speed sensor. The power split mechanism includes a planetary gear mechanism including a sun gear connected to the first MG rotary shaft, a ring gear connected to the second MG rotary shaft, and a planetary gear connected to the engine rotary shaft. Divided and transmitted to the first MG and propeller shaft. A correlation speed equation based on the speed diagram of the planetary gear mechanism is established among the first MG rotation speed, the second MG rotation speed, and the engine rotation speed.

The failure determination device of the present invention is characterized in that when both of the following two steps are satisfied, it is determined that the second MG rotational speed sensor is in a “provisional failure state” in which at least there is a possibility of failure. To do.
(1) A comparison is made between the second MG rotation speed sensor value, which is a detection value of the second MG rotation speed sensor, and the second MG rotation speed calculation value calculated from the first MG rotation speed and the engine rotation speed using the correlation speed equation. In the “2MG rotational speed evaluation step”, the absolute value of the second MG rotational speed deviation, which is the difference between the second MG rotational speed sensor value and the second MG rotational speed calculated value, is equal to or greater than a predetermined rotational speed deviation threshold.

(2) Based on the gear ratio between the sun gear and the ring gear of the power split mechanism based on the actual torque of the engine or the directly estimated torque directly estimated from the information on the behavior of the engine and the actual torque or estimated torque of the first MG In the “engine torque evaluation step” in which the indirect estimated torque calculated by multiplying the proportionality constant is compared, the absolute value of the engine torque estimated deviation that is the difference between the actual torque of the engine or the directly estimated torque and the indirectly estimated torque is a predetermined value. It is less than the torque deviation threshold.
In the present invention, it is possible to determine a functional failure of the second MG rotation speed sensor without adding new calculation means or the like based on information such as a rotation speed sensor value used in normal control.

  Here, in order to execute the engine torque evaluation step, it is assumed that the engine is in operation. Therefore, when the engine is stopped, it is preferable to execute the engine torque evaluation step after starting the engine. As the directly estimated torque in the engine torque evaluation step, for example, the engine target torque calculated based on the throttle opening or intake air amount or the engine speed can be used. Further, as the torque of the first MG serving as the basis for calculating the indirect estimated torque, for example, an estimated torque calculated based on the dq axis current that is energized to the first MG can be used.

By the way, even if it is determined that the second MG rotational speed sensor is in a temporary failure state, there is a possibility that the normal recovery will occur after the temporary temporary failure state. Therefore, it is preferable to execute “main failure determination processing” for monitoring a predetermined main failure determination parameter from the time when it is determined that the state is a temporary failure state. In the failure determination process, when the absolute value of the estimated engine torque deviation is less than the torque deviation threshold and the failure determination parameter exceeds a predetermined determination threshold, it is determined that the second MG rotation speed sensor is broken. As the failure determination parameter, a second MG rotation speed deviation excessive duration, a second MG rotation speed deviation, a time integrated value of the second MG rotation speed deviation, or the like can be used.

The block diagram of the failure determination apparatus of the vehicle by embodiment of this invention. (A) When the vehicle is stopped, (b) During EV traveling by the second MG, (c) When traveling by the engine and the second MG, (d) Each collinear diagram when the rotation of the second MG is increased from the state of (c) . The flowchart which shows the rotation speed sensor failure determination process by embodiment of this invention. The map which shows the relationship between a throttle opening degree (or intake air amount), an engine speed, and an engine target torque. The time chart when the excessive state of MG2 rotation speed deviation is continuing in this fault determination processing by 1st Embodiment of this invention. The time chart when it returns to normal from the MG2 rotation speed deviation excessive state in this fault determination processing by 1st Embodiment of this invention. The time chart when the excessive state of MG2 rotation speed deviation is continuing in this fault determination processing by 2nd Embodiment of this invention. The time chart when the excessive state of MG2 rotation speed deviation is continuing in this fault determination processing by 3rd Embodiment of this invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In the plurality of embodiments, substantially the same configuration is denoted by the same reference numeral and description thereof is omitted.
(Basic configuration)
First, refer to FIG. 1 and FIG. 2 for an outline of a basic configuration of a hybrid vehicle to which a vehicle failure determination apparatus according to an embodiment of the present invention is applied and a speed diagram (collinear diagram) in a power split mechanism. To explain. This hybrid vehicle is a so-called series-parallel hybrid vehicle.

  As shown in FIG. 1, the hybrid vehicle 10 includes an engine 50 and two motor generators as a driving force source. The “motor generator” has both a function as a generator that generates electric power by receiving torque and a function as an electric motor that generates torque by consuming electric power, and is hereinafter referred to as “MG”. The first MG 30 is mainly used as a generator, and the second MG 40 is mainly used as an electric motor. The first MG 30 and the second MG 40 are, for example, permanent magnet type synchronous three-phase AC motors.

The rotation shafts of engine 50, first MG 30 and second MG 40 are connected by power split mechanism 20.
The engine 50 is, for example, a 4-cylinder gasoline engine. The power of the engine 50 is divided into two systems by the power split mechanism 20, one of the power is transmitted to the propeller shaft 17 to drive the wheels 14, and the other power is transmitted to the first MG 30 to generate the first MG 30. Let

  The first MG 30 and the second MG 40 are connected to the battery 31 via the corresponding inverters 33 and 34 and the boost converter 32, respectively, and exchange power with the battery 31. The battery 31 is a power storage device that is configured by, for example, a secondary battery such as nickel metal hydride or lithium ion, or an electric double layer capacitor, and is capable of charging and discharging DC power.

  Boost converter 32 boosts the voltage of battery 31 and outputs the boosted voltage. Inverters 33 and 34 are composed of a plurality of bridge-connected switching elements, and convert DC power and three-phase AC power to each other. Since the configuration of the boost converter 32 and the inverters 33 and 34 is a well-known technique, a detailed description thereof will be omitted.

Regarding the first MG 30, mainly, the three-phase AC power generated by the first MG 30 is converted into DC power by the inverter 33 and regenerated to the battery 31 via the boost converter 32.
Regarding the second MG 40, the DC power of the battery 31 is mainly input to the inverter 34 via the boost converter 32, converted into three-phase AC power, and supplied to the second MG 40. The second MG 40 uses the power charged in the battery 31 or directly uses the power generated by the first MG 30 to drive the wheels 14 via the propeller shaft 17.

  Further, the first MG 30, the second MG 40, and the engine 50 are provided with rotation speed sensors that detect the respective rotation speeds. Here, the “rotational speed sensor” includes a sensor that detects a physical quantity that can be converted into a rotational speed and a rotational speed, such as a “rotational angle sensor” that directly detects a rotational angle of a mechanical angle or an electrical angle. Hereinafter, the “detection value” or “sensor value” of the rotation speed sensor includes a conversion value converted from a rotation angle or the like.

A first MG rotational speed sensor 35 and a second MG rotational speed sensor 45 are provided in the vicinity of the rotors of the first MG 30 and the second MG 40, respectively. The first MG rotation speed sensor 35 and the second MG rotation speed sensor 45 are, for example, resolvers. In addition, a rotary encoder or the like may be used.
The engine 50 is provided with a crank angle sensor 55 that detects the crank angle of the crankshaft 15 as an “engine speed sensor”. Hereinafter, the crank angle sensor 55 is referred to as an “engine speed sensor 55” for the purpose of the description.

Next, PM-ECU 61, MG-ECU 63, and engine ECU 65, which are control devices for hybrid vehicle 10, will be described. These ECUs are constituted by a microcomputer or the like, and have a CPU, a ROM, an I / O, a bus line for connecting them, and the like. These ECUs perform control by software processing by executing a program stored in advance by the CPU or hardware processing by a dedicated electronic circuit.
Hereinafter, for each ECU, the main functions and functions related to the features of the present invention will be briefly described.

PM (Power Management) -ECU 61 receives an accelerator signal from an accelerator sensor, a brake signal from a brake switch, a shift signal from a shift switch, a vehicle speed signal related to the speed of the vehicle, and the like based on the acquired information. Overall operation status is judged. The PM-ECU 61 communicates signals between the MG-ECU 63 and the engine ECU 65, and comprehensively controls the driving of the first MG 30, the second MG 40, and the engine 50.
The PM-ECU 61 corresponds to the “vehicle failure determination device” of the present invention. The effect of the PM-ECU 61 as the failure determination device will be described in detail later.

  The MG-ECU 63 acquires the first MG rotation speed Ng and the second MG rotation speed Nm from the first MG rotation speed sensor 35 and the second MG rotation speed sensor 45. The MG-ECU 63 controls the switching operation of the boost converter 32 and the inverters 33 and 34 based on the torque command instructed from the PM-ECU 61 and the acquired information such as the rotational speeds Ng and Nm. The energization to 2MG40 is controlled.

The engine ECU 65 controls the operation of the engine 50 based on information such as the engine speed Ne acquired from the engine speed sensor 55.
Further, the PM-ECU 61 comprehensively controls the driving force based on information communicated from the MG-ECU 63 and the engine ECU 65, so that the hybrid vehicle 10 travels only by the engine 50, EV travel only by the second MG 40, engine The traveling by both 50 and the second MG 40 can be switched.

Next, the power split mechanism 20 will be described.
The power split mechanism 20 includes a planetary gear mechanism that includes a sun gear 23, a ring gear 24, and a planetary gear 25. The sun gear 23 is connected to the rotation shaft of the first MG 30, and the planetary gear 25 is connected to the crankshaft 15 of the engine 50 via a carrier. A rotation shaft of the second MG 40 is connected to the ring gear 24 via the reduction gear mechanism 18. The power of the ring gear 24 is transmitted to the propeller shaft 17 and further transmitted to the wheels 14 via the differential gear mechanism 19 and the axle 13.

  In the power split mechanism 20, when the rotation speed of two axes among the three axes of the sun gear 23, the ring gear 24, and the planetary gear 25 is determined, the rotation speed of the remaining one axis is determined. That is, as shown in the alignment chart of FIG. 2, the first MG rotation speed Ng, the engine rotation speed Ne, and the second MG rotation speed Nm are connected by a straight line on the alignment chart. Assuming that the gear ratio obtained by dividing the number of teeth of the sun gear 23 by the number of teeth of the ring gear 24 is ρ, the engine rotational speed Ne internally divides the first MG rotational speed Ng and the second MG rotational speed Nm into “1: ρ”. Value.

For simplification, assuming that the gear ratio of the reduction gear mechanism 18 is 1, and the second MG rotational speed Nm is equal to the rotational speed (Np) of the propeller shaft 17, the engine rotational speed Ne, the first MG rotational speed Ng, and the second MG rotational speed Nm With respect to the relationship, the correlation velocity formula of formula (1.1) is established.
Ne = (ρNg + Nm) / (1 + ρ) (1.1)
When formula (1.1) is expanded for the second MG rotation speed Nm, formula (1.2) is obtained.
Nm = (1 + ρ) Ne−ρNg (1.2)

Further, it is known that the correlation torque equation (2) is established between the engine torque Te and the first MG torque Tg.
Te = {− (1 + ρ) / ρ} × Tg (2)
Here, assuming that “Kρ = (1 + ρ) / ρ”, the expression (2) is an expression (2 ′) using a “proportional constant (−Kρ) based on the gear ratio between the sun gear 23 and the ring gear 24”. expressed.
Te = −Kρ × Tg (2 ′)

The nomograph of FIG. 2 shows how the first MG rotation speed Ng, the engine rotation speed Ne, and the second MG rotation speed Nm change in conjunction with the traveling state of the vehicle.
FIG. 2A shows the vehicle stop state, and each of the rotation speeds Ng, Ne, and Nm is 0.
FIG. 2B shows a state in which the engine 50 is not started and the EV traveling is performed only by the second MG 40. The second MG rotation speed Nm is a positive value, and the first MG rotation speed Ng is a negative value.
FIG. 2C shows a state where the engine 50 is started and the vehicle is running on both the engine 50 and the second MG 40. Each rotational speed Ng, Ne, Nm is a positive value.
FIG. 2 (d) shows a state in which the second MG speed Nm is increased without changing the engine speed Ne from the state of FIG. 2 (c). The first MG rotation speed Ng is a negative value.

As described above, assuming that the power split mechanism 20 is normal, when the rotation speeds of the first MG 30, the second MG 40, and the engine 50 are normally detected, the equations (1.1) and (1.2) The correlation speed equation is established, and the rotation speeds are connected in a straight line on the alignment chart of FIG.
On the contrary, if any one of the rotation speeds of the first MG 30, the second MG 40, and the engine 50 is not normally detected, the correlation speed equation is not established. Conversely, if the correlation speed equation does not hold, it is estimated that one of the rotation speed sensor values is abnormal, that is, one of the rotation speed sensors has failed.

The present invention is based on the above technical idea and aims to determine a failure of the rotational speed sensor in the hybrid vehicle 10, particularly a failure of the second MG rotational speed sensor 45.
Here, the failure modes of the resolver are roughly classified into a resolver internal failure and a resolver external failure. Resolver internal faults include short-circuit between phases, out of voltage range, disconnection, short circuit, etc., and these internal faults can be determined by the resolver output voltage.
On the other hand, the resolver external failure is a functional failure in which the actual rotational speed and the detected rotational speed do not match when the resolver is detached from the MG rotor. This external failure cannot be determined by the resolver output voltage. . Accordingly, an object of the present invention is to provide a failure determination device that can determine a resolver external failure for the second MG 40 in particular.

In the embodiment of the present invention, the PM-ECU 61 as the “failure determination device” executes “rotational speed sensor failure determination processing” described below, whereby a new calculation means as in the prior art (Patent Document 1) is performed. A failure of the second MG rotation speed sensor 45 is determined without adding the above.
Next, the rotational speed sensor failure determination processing by the PM-ECU 61 will be described with reference to the flowchart of FIG. In the description of the flowchart, the symbol “S” means a step.

  S01 and S02 correspond to the “second MG rotational speed evaluation step” recited in the claims. In S01, the second MG speed sensor value Nm_sns, the engine speed sensor value Ne_sns, and the first MG speed sensor value Ng_sns are obtained from the second MG speed sensor 45, the engine speed sensor 55, and the first MG speed sensor 35, respectively. To do.

In S02, first, a second MG rotation speed calculation value Nm_cal is calculated by the correlation speed equation (1.2) based on the engine rotation speed sensor value Ne_sns and the first MG rotation speed sensor value Ng_sns.
Nm_cal = (1 + ρ) Ne_sns−ρNg_sns (1.2)

Then, it is determined whether or not the second MG rotation speed sensor value Nm_sns is equal to the second MG rotation speed calculated value Nm_cal. That is, the success or failure of the following formula (3) is evaluated.
Nm_sns≈Nm_cal (3)
To determine whether or not they are equal, the absolute value of the second MG rotation speed deviation ΔNm, which is the difference between the second MG rotation speed sensor value Nm_sns and the second MG rotation speed calculated value Nm_cal, is compared with a predetermined rotation speed deviation threshold value α. By doing. The rotational speed deviation threshold value α is set to a value of 0 or more in consideration of a detection error and a calculation error that can normally occur.

When the absolute value of the second MG rotation speed deviation ΔNm is less than the rotation speed deviation threshold α, it is determined that the second MG rotation speed sensor value Nm_sns is equal to the second MG rotation speed calculated value Nm_cal (S02: YES), and processing Exit.
When the absolute value of the second MG rotation speed deviation ΔNm is greater than or equal to the rotation speed deviation threshold α, it is determined that the second MG rotation speed sensor value Nm_sns and the second MG rotation speed calculated value Nm_cal are not equivalent (S02: NO), and the process proceeds to S03. Transition.

When NO is determined in S02, the correlation speed equation of the power split mechanism 20 is not established, and any of the second MG rotation speed sensor 45, the first MG rotation speed sensor 35, and the engine rotation speed sensor 55 has failed. Presumed. Therefore, in the next steps S05 and S06, it is determined whether the failure is in the second MG rotation speed sensor 45 or the failure in the engine rotation speed sensor 55 or the first MG rotation speed sensor 35.
S03 and S04 are steps for confirming that the engine 50 is in operation as a premise for executing S05 and S06. If the crankshaft 15 of the engine 50 is not rotating at this stage (Ne_sns≈0) and it is determined that the engine 50 is stopped (S03: YES), the engine 50 is started in S04.

  S05 and S06 correspond to the “engine torque evaluation step” recited in the claims. In the engine torque evaluation step, whether or not the “equation relating to engine torque” that should be satisfied if the engine speed Ne and the first MG speed Ng are normally reflected is determined. If this equation about the engine torque is established (S06: YES), the engine speed sensor 55 and the first MG speed sensor 35 are normal, and the second MG speed sensor 45 is set to “provisional failure state” by the elimination method. ] (S07). On the other hand, if the above equation regarding the engine torque does not hold (S06: NO), it is determined that the failure is not the failure of the second MG rotation speed sensor 45 but the failure of the engine rotation speed sensor 55 or the first MG rotation speed sensor 35. (S10).

In the present embodiment, the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1 are compared in the “equation for engine torque”. In S05, the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1 are calculated. Note that “calculation” includes reference to a map.
In S06, it is determined whether or not the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1 are equal. That is, the success or failure of the following formula (4) is evaluated.
Te_tgt≈Te_est_mg1 (4)

The engine target torque Te_tgt on the left side of Expression (4) is a target torque that is to be output to the engine 50 by, for example, the driver's accelerator operation. For example, as shown in the map of FIG. 4, the engine target torque Te_tgt is calculated based on the throttle opening and the engine speed Ne. The throttle opening may be replaced with the intake air amount.
The engine target torque Te_tgt is not an actual torque directly detected by a torque sensor but an estimated torque. However, instead of using the correlation torque equation of the power split mechanism 20, the “direct estimated torque” means that the torque is directly estimated from information on the behavior of the engine 50 such as the throttle opening or intake air amount and the engine speed Ne. "

  When referring to the map of FIG. 4, if the throttle opening or intake air amount and the engine speed Ne are correct, the engine target torque Te_tgt is equivalent to the engine actual torque Te_real. However, if the engine speed sensor value Ne_sns does not match the actual speed, the engine target torque Te_tgt calculated with reference to the map of FIG. 4 will deviate from the engine actual torque Te_real. Physically, it can be explained that if the engine speed sensor value Ne_sns is wrong, the target torque and the actual torque are shifted due to a difference in ignition, valve timing, intake air amount, and the like.

Subsequently, the engine indirect estimated torque Te_est_mg1 on the right side of Expression (4) is referred to as “indirect estimated torque” in the sense of torque estimated using the correlation torque expression (2) based on the torque Tg of the first MG 30.
Te_est_mg1 = {− (1 + ρ) / ρ} × Tg = −Kρ × Tg (2)
If the power split mechanism 20 is assumed to be normal and the torque Tg of the first MG 30 is correct, the engine target torque Te_tgt is equivalent to the engine actual torque Te_real.

The engine indirect estimated torque Te_est_mg1 may further use the actual torque Tg_real detected by the torque sensor or the estimated torque Tg_est based on another physical quantity as the torque Tg of the first MG 30 that is the basis of calculation.
In the present embodiment, the estimated torque Tg_est calculated by Expression (5) based on the dq-axis current that is energized to the first MG 30 is employed as the torque Tg of the first MG 30.
Tg_est = p × {ψ × iq + (Ld−Lq) × id × iq} (5)

The symbols are as follows.
p: number of pole pairs of AC motor id, iq: d-axis current, q-axis current Ld, Lq: d-axis self-inductance, q-axis self-inductance ψ: armature interlinkage magnetic flux of permanent magnet

Here, the dq-axis currents id and iq are dq-transformed by the equation (6) based on the three-phase currents iu, iv and iw and the electrical angle θ.

If the first MG rotation speed sensor value Ng_sns does not match the actual rotation speed, the value of the electrical angle θ in the equation (6) is different from the actual value, so the estimated torque Tg_est calculated by the equation (5) is The value is different from the actual torque. Physically, if the first MG rotation speed Ng is wrong, it is impossible to synchronize the magnetic flux of the coil with the magnetic flux of the magnet, so that it can be explained that the estimated torque and the actual torque are shifted.
When the wrong first MG estimated torque Tg_est is used as the basis for the calculation of Expression (2), the calculated engine indirect estimated torque Te_est_mg1 is deviated from the actual engine torque Te_real.

If the above matters are arranged, if the engine speed sensor value Ne_sns and the first MG speed sensor value Ng_sns are correct, the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1 are almost identical to the engine actual torque Te_real, The relationship of Formula (4 ′) is established.
Te_tgt≈Te_real≈Te_est_mg1 (4 ′)

  However, if the engine speed sensor value Ne_sns is wrong, “Te_tgt ≠ Te_real” is obtained, and if the first MG speed sensor value Ng_sns is wrong, “Te_real ≠ Te_est_mg1” is obtained. The relationship will no longer hold.

Returning to the description of the flowchart, in S06, based on the above reason, the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1 are compared to determine whether or not they are equivalent.
The determination of whether or not they are equivalent is performed by comparing the absolute value of the engine torque estimated deviation ΔTe, which is the difference between the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1, with a predetermined torque deviation threshold ε. The torque deviation threshold value ε is set to a value equal to or greater than 0 in consideration of detection errors and calculation errors that can normally occur.

  When the absolute value of the estimated engine torque deviation ΔTe is equal to or greater than the torque deviation threshold ε, it is determined that the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1 are not equivalent (S06: NO). In this case, it is determined in S10 that the engine speed sensor 55 or the first MG speed sensor 35 has failed. In the present embodiment, it is not determined which of the engine speed sensor 55 or the first MG speed sensor 35 is malfunctioning.

  When the absolute value of the estimated engine torque deviation ΔTe is less than the torque deviation threshold ε, it is determined that the engine target torque Te_tgt and the engine indirect estimated torque Te_est_mg1 are equivalent (S06: YES). That is, since it is considered that the engine speed sensor 55 and the first MG speed sensor 35 are normal, it is estimated that there is a high possibility that the second MG speed sensor 45 is broken by the erasing method.

  There may be a pattern in which it is determined that the second MG rotation speed sensor 45 has failed at this stage. However, in this embodiment, the failure is not fixed immediately, but the process proceeds to S07. In S07, it is determined that the “secondary MG rotation speed sensor 45” is in a “provisional failure state” in which there is a possibility of failure, and this failure determination process is started.

In the failure determination process, it is monitored whether or not the failure determination parameter exceeds a predetermined threshold value. The “main failure determination parameter” is information for supporting that there is a high probability that the second MG rotation speed sensor 45 has actually failed, and will be specifically described in a plurality of embodiments described later.
When the failure determination parameter exceeds a predetermined threshold (S08: YES), it is determined in S09 that the failure is in the second MG rotation speed sensor 45, and the process ends. When the failure determination parameter is equal to or less than the predetermined threshold (S08: NO), the process returns to before S01 and the routine is repeated.

  Thus, in the present embodiment, the PM-ECU 61 can determine the failure of the second MG rotation speed sensor 45 in particular by executing the rotation speed sensor failure determination process as the failure determination device. Here, the information used for the failure determination process is information such as each rotation speed sensor value used in the normal control, and it is not necessary to add a new calculation unit or the like.

Next, the “main failure determination parameter” in the main failure determination process executed by the PM-ECU 61 will be described for each embodiment with reference to a time chart.
(First embodiment)
The failure determination process according to the first embodiment of the present invention will be described with reference to the time charts of FIGS. 5 and 6 and the alignment chart of FIG.
5 and 6, (a) to (f) have a common time axis as a horizontal axis, and (a) a second MG rotational speed sensor value Nm_sns, (b) an engine rotational speed sensor value Ne_sns, and (c) a first MG. Rotational speed sensor value Ng_sns, (d) engine torque estimated deviation ΔTe, (e) second MG rotational speed deviation excessive duration, and (f) this failure determination signal are on the vertical axis. The second MG rotation speed deviation excessive continuation time of (e) corresponds to this failure determination parameter of the first embodiment.

5B, 6B, 6C, and 6D are completely the same. Also, in (a), (e), and (f), the period from time t0 to time t4 is common. First, common parts will be described.
At time t0, the vehicle is in a stop state corresponding to FIG. 2A, and the second MG rotation speed sensor value Nm_sns, the engine rotation speed sensor value Ne_sns, and the first MG rotation speed sensor value Ng_sns are all zero.
Between time t0 and time t1, the engine 50 is not started and the vehicle is running on EV at the second MG 40, which corresponds to FIG. The second MG rotation speed sensor value Nm_sns is a positive value, and the first MG rotation speed sensor value Ng_sns is a negative value.

  At time t1, the engine 50 is started and the engine speed sensor value Ne_sns becomes a positive value. Thereafter, the engine speed sensor value Ne_sns maintains a constant value. Immediately after time t1, the state corresponds to FIG. 2C, and the second MG rotation speed sensor value Nm_sns, the engine rotation speed sensor value Ne_sns, and the first MG rotation speed sensor value Ng_sns are all positive values.

  Further, as shown in FIGS. 5 and 6D, the first MG 30 generates a negative regenerative torque Tg. Therefore, the engine indirect estimated torque Te_est_mg1 (solid line) calculated from the equation (2) is a positive value. On the other hand, the engine target torque Te_tgt (broken line) is calculated from the map of FIG. 4 based on the throttle opening and the engine speed sensor value Ne_sns. The absolute value of the estimated engine torque deviation ΔTe, which is the difference between the engine target torque Te_tgt and the estimated engine torque Te_est, is less than the torque deviation threshold ε.

As indicated by a broken line in FIGS. 5 and 6A, the actual rotational speed Nm_real of the second MG increases linearly from time t0. Then, since the state of FIG. 2C shifts to the state of FIG. 2D, the value of the first MG rotation speed sensor value Ng_sns changes from positive to negative at time t4.
The second MG rotation speed calculation value Nm_cal calculated from the engine rotation speed sensor value Ne_sns and the first MG rotation speed sensor value Ng_sns using the correlation speed equation (1.2) is equivalent to the actual rotation speed Nm_real.

From time t0 to time t2, the second MG rotation speed sensor 45 is normal, and the second MG rotation speed sensor value Nm_sns matches the actual rotation speed Nm_real.
However, a situation is assumed in which a functional failure of the second MG rotation speed sensor 45 occurs at time t2 and the sensor value Nm_sns is fixed to a constant value. Then, the actual rotational speed Nm_real and the sensor value Nm_sns begin to deviate, and the second MG rotational speed deviation ΔNm gradually increases.

At time t3, when the absolute value of the second MG rotation speed deviation ΔNm becomes equal to or greater than the rotation speed deviation threshold α, the PM-ECU 61 determines that the second MG rotation speed sensor 45 is in the “provisional failure state”, and this failure determination Start processing. In the first embodiment, as shown in (e), counting of the second MG rotation speed deviation excessive continuation time, which is the failure determination parameter, is started.
The above is description of the common part of FIG. 5, FIG.

Next, the parts unique to FIG. 5 will be described.
In FIG. 5, after time t3, the second MG rotation speed sensor value Nm_sns is fixed to a constant value, and the state where the absolute value of the second MG rotation speed deviation ΔNm is equal to or greater than the rotation speed deviation threshold α continues. The counter for the excessive duration of the number deviation increases linearly. When the second MG rotation speed deviation excessive duration time exceeds the determination threshold C at time t6, the PM-ECU 61 outputs this failure determination signal and determines that the second MG rotation speed sensor 45 has failed.

  Next, in FIG. 6, for comparison with FIG. 5, after this failure determination process is started at time t <b> 3, the second MG rotation speed sensor value Nm_sns again approaches the second MG actual rotation speed Nm_real, and the second MG rotation speed deviation ΔNm A case where the absolute value returns to a normal state below the rotation speed deviation threshold value α will be described.

After time t3, the counter of the second MG rotation speed deviation excessive continuation time increases, but the increase in the counter stops because the absolute value of the second MG rotation speed deviation ΔNm falls below the rotation speed deviation threshold α at time t5. Then, at time t7 when a predetermined monitoring time Tw has elapsed from time t3, if the second MG rotation speed deviation excessive continuation time does not exceed the determination threshold C, the counter is reset and the main failure determination signal is not output. The failure determination process ends.
As a result, when a normal failure occurs temporarily after a temporary failure state has occurred temporarily, it can be excluded from targets for subsequent failure handling.

Next, an embodiment in which the main failure determination process is executed using other main failure determination parameters will be described.
(Second Embodiment)
The failure determination process according to the second embodiment of the present invention will be described with reference to the time chart of FIG. FIG. 7 differs from FIG. 5 only in (e). In the second embodiment, “second MG rotation speed deviation” is monitored as the failure determination parameter. FIG. 7 illustrates a case where the value of the second MG rotation speed deviation ΔNm is positive.

In the second embodiment, for the second MG rotation speed deviation ΔNm, in addition to the rotation speed deviation threshold value α, a determination threshold value β that is a value larger than the threshold value α is set. This failure determination signal is output at time t6 when the second MG rotation speed deviation ΔNm further exceeds the threshold α and exceeds the determination threshold β.
If the second MG rotation speed deviation ΔNm does not exceed the determination threshold value β within a predetermined monitoring time from time t3, the failure determination process ends when the monitoring time increases, as in FIG. 6 of the first embodiment. May be. If the second MG rotation speed deviation Δm is a negative value, the absolute value may be evaluated in the same manner.

(Third embodiment)
The failure determination process according to the third embodiment of the present invention will be described with reference to the time chart of FIG. FIG. 8 differs from FIG. 5 only in (e). In the third embodiment, “time integrated value of second MG rotation speed deviation” is monitored as the failure determination parameter. The time integrated value of the second MG rotational speed deviation is a value obtained by integrating the second MG rotational speed deviation ΔNm on the time axis from the time t3, that is, a time integrated value calculated by the expression “Σ (ΔNm · Δt)”. means. FIG. 8 illustrates a case where the value of the second MG rotation speed deviation ΔNm is positive.
When the second MG rotation speed deviation ΔNm increases in proportion to time, the time integrated value of the second MG rotation speed deviation increases in a parabolic shape. Then, this failure determination signal is output at time t6 when the time integrated value of the second MG rotation speed deviation exceeds the determination threshold γ.

  As described above, even when the failure determination parameters of the second and third embodiments are used, the failure determination process can be appropriately executed as in the first embodiment. A plurality of the failure determination parameters exemplified in the first to third embodiments may be combined.

(Other embodiments)
(A) Regarding the second MG rotational speed evaluation step, the time charts of FIGS. 5 to 8 show examples in which the second MG rotational speed Nm gradually increases, but the same applies to the case where the second MG rotational speed Nm gradually decreases. Further, the value of the rotational speed deviation threshold value α may be changed depending on the magnitude of the second MG rotational speed sensor value Nm_sns and the second MG rotational speed calculated value Nm_cal, that is, the sign of the second MG rotational speed deviation ΔNm. Similarly, the value of the torque deviation threshold ε in the engine torque evaluation step may be changed depending on whether the engine torque estimated deviation ΔTe is positive or negative.

(A) Regarding the engine torque evaluation step, the hybrid vehicle 10 may include at least one of an engine torque sensor that directly detects the actual engine torque Te_real or a first MG torque sensor that directly detects the first MG actual torque Tg_real.
When the engine torque sensor is provided, the engine actual torque Te_real may be used instead of the engine target torque Te_tgt for the left side of the equation (4) in S06 in the flowchart of FIG. In this case, the failure of the engine speed sensor 55 is not assumed.

  When the first MG torque sensor is provided, the actual torque Tg_real is used in place of the estimated torque Tg_est estimated by the equation (5) as the first MG torque that is the basis for calculating the engine indirect estimated torque Te_est_mg1 on the right side of the equation (4). May be. In this case, the failure of the first MG rotation speed sensor 35 is not assumed.

  (C) In the rotational speed sensor failure determination process, it is determined that the second MG rotational speed sensor 45 has failed at the stage where YES is determined in S06 in the flowchart of FIG. 2, and this failure determination process is not executed. Good.

(D) The subject that executes the rotational speed sensor failure determination process of the present invention is not limited to the PM-ECU 61, and other ECUs may also serve as the function.
As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

10 ... hybrid vehicle, 17 ... propeller shaft,
20 ... Power split mechanism,
23 ... Sun gear, 24 ... Ring gear, 25 ... Planetary gear,
30 ... 1st MG, 35 ... 1st MG rotation speed sensor,
40 ... 2nd MG, 45 ... 2nd MG rotation speed sensor,
50 ... engine, 55 ... crank angle sensor (engine speed sensor),
61 ... PM-ECU (failure determination device).

Claims (6)

The first MG (30);
The second MG (40);
An engine (50);
A planetary gear mechanism comprising a sun gear (23) connected to the rotation shaft of the first MG, a ring gear (24) connected to the rotation shaft of the second MG, and a planetary gear (25) connected to the rotation shaft of the engine. A power split mechanism (20) configured to split the power of the engine and transmit it to the first MG and the propeller shaft (17);
A first MG rotation speed sensor (35) for detecting a first MG rotation speed (Ng) which is the rotation speed of the first MG;
A second MG rotation speed sensor (45) for detecting a second MG rotation speed (Nm) which is the rotation speed of the second MG;
An engine speed sensor (55) for detecting an engine speed (Ne) which is the engine speed;
And is applied to a hybrid vehicle (10) in which a correlation speed equation based on a speed diagram of a planetary gear mechanism is established among the first MG rotation speed, the second MG rotation speed, and the engine rotation speed,
A second MG rotation speed sensor value that is a detection value of the second MG rotation speed sensor is compared with a second MG rotation speed calculation value calculated from the engine rotation speed and the first MG rotation speed using the correlation speed equation. In the second MG rotational speed evaluation step, the absolute value of the second MG rotational speed deviation (ΔNm), which is the difference between the second MG rotational speed sensor value and the second MG rotational speed calculated value, is equal to or greater than a predetermined rotational speed deviation threshold (α). And
The actual torque of the engine or the directly estimated torque estimated directly from the information on the behavior of the engine and the actual torque or estimated torque of the first MG to the gear ratio between the sun gear and the ring gear of the power split mechanism In the engine torque evaluation step of comparing the indirect estimated torque calculated by multiplying the proportional constant based on the actual torque of the engine or the difference between the direct estimated torque and the indirect estimated torque, the engine torque estimated deviation (ΔTe) When the absolute value is less than a predetermined torque deviation threshold (ε),
A vehicle failure determination device (61), characterized in that it is determined that the second MG rotation speed sensor is in a temporary failure state where there is a possibility that at least there is a failure.   When it is determined in the second MG rotational speed evaluation step that the absolute value of the second MG rotational speed deviation is equal to or greater than the rotational speed deviation threshold, the engine torque is started after the engine is started when the engine is stopped. The vehicle failure determination device according to claim 1, wherein an evaluation step is executed.   The direct estimated torque used in the engine torque evaluation step is an engine target torque calculated based on a throttle opening or intake air amount and the engine speed. Vehicle failure determination device.   The torque of the first MG, which is a basis for calculating the indirect estimated torque in the engine torque evaluation step, is an estimated torque calculated based on a dq-axis current passed through the first MG. The vehicle failure determination device according to any one of claims 1 to 3.   When it is determined that the second MG rotational speed sensor is in the temporary failure state, a main failure determination process for monitoring a predetermined main failure determination parameter is executed, and the absolute value of the engine torque estimation deviation is less than the torque deviation threshold value. And when the failure determination parameter exceeds a predetermined determination threshold value, it is determined that the second MG rotational speed sensor is in failure. The vehicle failure determination device described. The failure determination parameter is
Second MG rotational speed deviation, second MG rotational speed deviation, which is a time during which the state where the absolute value of the second MG rotational speed deviation is equal to or greater than the rotational speed deviation threshold has continued since the occurrence of the temporary failure state. 6. The vehicle failure determination device according to claim 5, wherein the vehicle failure determination device is any one or more of the time integrated values of the second MG rotation speed deviation.

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