JP2020132109A - Hybrid vehicle - Google Patents

Abstract

To provide a hybrid vehicle which can early finish the learning of a fuel injection characteristic and the detection of an abnormality.SOLUTION: An engine ECU 73 controls an injection valve so as to perform active fuel injection including learning partial lift injection necessary for performing at least either of the learning of an injection characteristic of a fuel injection valve 23 at partial lift injection, and the detection of an abnormality. When the active fuel injection is performed, the engine ECU performs control for operating an internal combustion engine at a learning motion point which is displaced to a side at which an optimum engine motion point is displaced to a side at which an engine rotational speed is increased higher than an engine rotational speed corresponding to the optimum engine motion point on an equal output line.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hybrid vehicle including an internal combustion engine and an electric motor.

Patent Document 1 discloses a fuel injection control device. This fuel injection control device controls the fuel injection valve, and sets the required injection amount, which is the fuel injection amount required for the fuel injection valve, other than the predetermined injection amount, which is the injection amount of the partial lift injection, and the predetermined injection amount. It is divided into the prepared injection amount and injected into the internal combustion engine (this injection is also referred to as "active injection"). Then, the fuel injection control device learns the injection characteristics of the fuel injection valve at the time of partial lift injection by executing active injection a predetermined number of times.

Japanese Unexamined Patent Publication No. 2015-190318

By the way, a hybrid vehicle equipped with an internal combustion engine and an electric motor is also equipped with a fuel injection valve for injecting fuel into the internal combustion engine. Even in a hybrid vehicle, learning the injection characteristics of the fuel injection valve during partial lift injection (injection characteristic learning) and detecting an abnormality in the fuel injection valve (abnormality detection) are performed. Even in a hybrid vehicle, it is necessary to operate an internal combustion engine because active injection needs to be performed in order to perform injection characteristic learning and abnormality detection of the fuel injection valve.

However, in a hybrid vehicle, if the load on the internal combustion engine is low, the operation of the internal combustion engine will be stopped due to intermittent operation, so there is an opportunity (frequency) to learn the injection characteristics of the fuel injection valve and detect abnormalities. , State) is reduced.

The present invention has been made to address the above-mentioned problems. That is, one of the objects of the present invention is to increase the chances of executing the injection characteristic learning and abnormality detection of the fuel injection valve by enabling the injection characteristic learning and abnormality detection of the fuel injection valve to be completed at an early stage. It is an object of the present invention to provide a hybrid vehicle that can be used (hereinafter, also referred to as "hybrid vehicle of the present invention").

The hybrid vehicle of the present invention is a hybrid vehicle including an internal combustion engine (20), a fuel injection valve (23) for injecting fuel into the internal combustion engine, and an electric motor (Mg1, MG2) (10), and is a drive shaft of the vehicle. A power transmission mechanism (50) that connects (53) and the internal combustion engine so as to be able to transmit torque and also connects the drive shaft and the electric motor so that torque can be transmitted, and the drive shaft that is determined according to the amount of accelerator operation by the user. A torque equal to the user-required torque, which is the torque required for the internal combustion engine, is controlled so as to act on the drive shaft by controlling the output torque of the internal combustion engine due to the operation of the internal combustion engine and the output torque of the electric motor. When the engine operation stop condition is satisfied, the operation of the internal combustion engine is stopped, and when the predetermined engine start condition is satisfied, the engine intermittent operation for starting the internal combustion engine is executed.
When the operation of the internal combustion engine is executed, it is the operating point of the internal combustion engine defined by the output torque of the internal combustion engine and the engine rotation speed of the internal combustion engine, and is the engine output required for the internal combustion engine. A driving force that controls the internal combustion engine to operate at the optimum engine operating point, which is the operating point specified based on the efficiency of the internal combustion engine, from the output line connecting the operating points corresponding to the engine required output. Control units (70, 73) and
Active fuel including partial lift injection for learning necessary for causing the fuel injection valve to execute partial lift injection at a predetermined injection timing and to learn the injection characteristics of the fuel injection valve and detect an abnormality at the time of partial lift injection. A fuel injection valve control unit (73) that controls the injection to be executed by the fuel injection valve, and
To be equipped.
The driving force control unit of the hybrid vehicle of the present invention
When the active fuel injection is performed
To operate the internal combustion engine on the equal output line at a learning operating point in which the optimum engine operating point is shifted to the side where the engine rotation speed increases from the engine rotation speed corresponding to the optimum engine operating point.
Using the raised engine required output as the engine required output, operating the internal combustion engine and
Prohibiting intermittent operation of the engine,
It is configured to perform at least one of them.

According to the hybrid vehicle of the present invention, when active fuel injection is executed, the injection characteristic learning and abnormality detection of the fuel injection valve can be completed at an early stage by increasing the number of fuel injections of the fuel injection valve per unit time. By doing so, it is possible to increase the chances of performing injection characteristic learning and abnormality detection of the fuel injection valve. ..

In the above description, in order to help the understanding of the present invention, the names and / or symbols used in the embodiments are added in parentheses to the configurations of the invention corresponding to the embodiments described later. However, each component of the present invention is not limited to the embodiment defined by the above name and / or reference numeral.

FIG. 1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view of a specific cylinder of an internal combustion engine. FIG. 3 is a graph showing the relationship between the engine rotation speed and the engine output torque and the optimum engine operation line. FIG. 4 is a graph for explaining injection characteristic learning and abnormality detection of the fuel injection valve. FIG. 5 is a flowchart showing a routine executed by the CPU of the power management ECU.

Hereinafter, the hybrid vehicle according to the embodiment of the present invention will be described with reference to the drawings.

<Composition>
As shown in FIG. 1, the hybrid vehicle 10 according to the embodiment of the present invention includes the generator motor MG1, the generator motor MG2, the engine 20, the power distribution mechanism 30, the driving force transmission mechanism 50, the first inverter 61, and the second inverter. It includes a 62, a battery 63, a power management ECU 70, a battery ECU 71, a motor ECU 72, and an engine ECU 73. The ECU is an abbreviation for an electric control unit, and is an electronic control circuit having a microcomputer including a CPU, ROM, RAM, an interface, and the like as a main component.

The generator motor (motor generator) MG1 is a synchronous generator motor that can function as either a generator or a motor. The generator motor MG1 is also referred to as a first generator motor MG1 for convenience. The first generator motor MG1 mainly exerts a function as a generator in this example. The first generator motor MG1 includes an output shaft (hereinafter, also referred to as a “first shaft”) 41.

The generator motor (motor generator) MG2 is a synchronous generator motor that can function as either a generator or a motor, like the first generator motor MG1. The generator motor MG2 is also referred to as a second generator motor MG2 for convenience. The second generator motor MG2 mainly exerts a function as a motor in this example. The second generator motor MG2 includes an output shaft (hereinafter, also referred to as a “second shaft”) 42.

The engine 20 is a 4-cycle, in-cylinder injection (direct injection), spark ignition type, multi-cylinder internal combustion engine. The engine 20 includes an intake passage portion 21 including an intake pipe and an intake manifold, a throttle valve 22, a throttle valve actuator 22a, a plurality of fuel injection valves 23, a plurality of ignition devices 25 including a spark plug, and a crank which is an output shaft of the engine 20. It includes a shaft 26, an exhaust manifold 27, an exhaust pipe 28, and a three-way catalyst 29 on the upstream side.

The throttle valve 22 is rotatably supported by the intake passage portion 21.
The throttle valve actuator 22a rotates the throttle valve 22 in response to an instruction signal from the engine ECU 73, and can change the passage cross section of the intake passage portion 21.

As shown in the enlarged view of FIG. 2, each of the plurality of fuel injection valves 23 (only one fuel injection valve 23 is shown in FIGS. 1 and 2) has its injection holes in the combustion chamber CC. It is arranged so as to be exposed inside. Each fuel injection valve 23 is adapted to directly inject the fuel of the fuel injection amount included in the in-cylinder fuel injection instruction signal into the combustion chamber CC of each cylinder in response to the in-cylinder fuel injection instruction signal. The fuel injection valve 23 is also referred to as an "in-cylinder fuel injection valve".

The engine ECU 73 calculates the in-cylinder intake air amount Mc sucked into one cylinder based on the intake air amount Ga and the engine rotation speed Ne measured by the air flow meter 91, and corresponds to the in-cylinder intake air amount Mc. The amount of fuel to be supplied to the engine 20 (hereinafter referred to as "required fuel amount Ft") is determined.

Each of the ignition devices 25 including the spark plug is adapted to generate an ignition spark at a predetermined timing in the combustion chamber of each cylinder in response to an instruction signal from the engine ECU 73.

The three-way catalyst 29 on the upstream side is an exhaust purification catalyst and is arranged in the exhaust collecting portion of the exhaust manifold 27. That is, the catalyst 29 is provided in the exhaust passage of the engine 20. The catalyst 29 purifies unburned substances (HC, CO, etc.) and NOx discharged from the engine 20.

The engine 20 changes the intake air amount by changing the opening degree of the throttle valve 22 by the throttle valve actuator 22a, and also changes the required fuel amount Ft, so that the engine 20 “engine output torque Te and engine rotation speed” "Ne (ie, engine output)" can be changed.

The power distribution mechanism 30 includes a well-known planetary gear device 31. The planetary gear device 31 includes a sun gear 32, a plurality of planetary gears 33, and a ring gear 34.

The sun gear 32 is connected to the first shaft 41 of the first generator motor MG1. Therefore, the first generator motor MG1 can output torque to the sun gear 32. Further, the first generator motor MG1 can be rotationally driven by the torque input from the sun gear 32 to the first generator motor MG1 (first shaft 41). The first generator motor MG1 can generate power by being rotationally driven by the torque input from the sun gear 32 to the first generator motor MG1.

Each of the plurality of planetary gears 33 meshes with the sun gear 32 and also meshes with the ring gear 34. The rotation shaft (rotation shaft) of the planetary gear 33 is provided on the planetary carrier 35. The planetary carrier 35 is held so as to be rotatable coaxially with the sun gear 32. Therefore, the planetary gear 33 can revolve while rotating on the outer circumference of the sun gear 32. The planetary carrier 35 is connected to the crankshaft 26 of the engine 20. Therefore, the planetary gear 33 can be rotationally driven by the torque input from the crankshaft 26 to the planetary carrier 35.

The ring gear 34 is held so as to be rotatable coaxially with the sun gear 32.

As described above, the planetary gear 33 meshes with the sun gear 32 and the ring gear 34. Therefore, when torque is input from the planetary gear 33 to the sun gear 32, the sun gear 32 is rotationally driven by the torque. When torque is input from the planetary gear 33 to the ring gear 34, the torque drives the ring gear 34 to rotate. On the contrary, when a torque is input from the sun gear 32 to the planetary gear 33, the planetary gear 33 is rotationally driven by the torque. When torque is input from the ring gear 34 to the planetary gear 33, the torque causes the planetary gear 33 to be rotationally driven.

The ring gear 34 is connected to the second shaft 42 of the second generator motor MG2 via the ring gear carrier 36. Therefore, the second generator motor MG2 can output torque to the ring gear 34. Further, the second motor generator MG2 can be rotationally driven by the torque input from the ring gear 34 to the second motor generator MG2 (second shaft 42). The second power generation motor MG2 can generate power by being rotationally driven by the torque input from the ring gear 34 to the second power generation motor MG2.

Further, the ring gear 34 is connected to the output gear 37 via the ring gear carrier 36. Therefore, the output gear 37 can be rotationally driven by the torque input from the ring gear 34 to the output gear 37. The ring gear 34 can be rotationally driven by the torque input from the output gear 37 to the ring gear 34.

The driving force transmission mechanism 50 includes a gear train 51, a differential gear 52, and a drive shaft (drive shaft) 53.

The gear train 51 connects the output gear 37 and the differential gear 52 by a gear mechanism so as to be able to transmit power. The differential gear 52 is attached to the drive shaft 53. Drive wheels 54 are attached to both ends of the drive shaft 53. Therefore, the torque from the output gear 37 is transmitted to the drive wheels 54 via the gear train 51, the differential gear 52, and the drive shaft 53. The hybrid vehicle 10 can travel by the torque transmitted to the drive wheels 54.

The first inverter 61 is electrically connected to the first generator motor MG1 and the battery 63. Therefore, when the first generator motor MG1 is generating power, the electric power generated by the first generator motor MG1 is supplied to the battery 63 via the first inverter 61. On the contrary, the first generator motor MG1 is rotationally driven by the electric power supplied from the battery 63 via the first inverter 61.

The second inverter 62 is electrically connected to the second generator motor MG2 and the battery 63. Therefore, the second generator motor MG2 is rotationally driven by the electric power supplied from the battery 63 via the second inverter 62. On the contrary, when the second generator motor MG2 is generating power, the electric power generated by the second generator motor MG2 is supplied to the battery 63 via the second inverter 62.

The electric power generated by the first generator motor MG1 can be directly supplied to the second generator motor MG2, and the electric power generated by the second generator motor MG2 can be directly supplied to the first generator motor MG1.

The battery 63 is a lithium ion battery in this example. However, the battery 63 may be a nickel-metal hydride battery or another secondary battery as long as it is a power storage device capable of discharging and charging.

The power management ECU 70 (hereinafter referred to as “PMECU70”) is connected to the battery ECU 71, the motor ECU 72, and the engine ECU 73 so as to exchange information by communication.

The PMECU 70 is connected to a power switch 81, a shift position sensor 82, an accelerator operation amount sensor 83, a brake switch 84, a vehicle speed sensor 85, and the like, and inputs output signals generated by these sensors.

The power switch 81 is a system activation switch for the hybrid vehicle 10. The PMECU 70 is configured to activate the system (become a Ready-On state) when the power switch 81 is operated while a vehicle key (not shown) is inserted into the key slot and the brake pedal is depressed. ing.

The shift position sensor 82 is adapted to generate a signal indicating a shift position selected by a shift lever (not shown) operably provided by the driver near the driver's seat of the hybrid vehicle 10. The shift position includes P (parking position), R (reverse position), N (neutral position) and D (running position).

The accelerator operation amount sensor 83 is adapted to generate an output signal indicating an operation amount (accelerator operation amount AP) of an accelerator pedal (not shown) provided so as to be operable by the driver. The accelerator operation amount AP can also be expressed as an acceleration operation amount.
The brake switch 84 is adapted to generate an output signal indicating that the brake pedal is in the operated state when the brake pedal (not shown) provided so as to be operable by the driver is operated.
The vehicle speed sensor 85 is adapted to generate an output signal representing the vehicle speed SPD of the hybrid vehicle 10.

The PMECU 70 is adapted to input the remaining capacity SOC (State Of Charge) of the battery 63 calculated by the battery ECU 71. The remaining capacity SOC is calculated by a well-known method based on the integrated value of the current flowing in and out of the battery 63.

The PMECU 70 receives a signal representing the rotation speed of the first generator motor MG1 (hereinafter referred to as “MG1 rotation speed Nm1”) and the rotation speed of the second generator motor MG2 (hereinafter, “MG2 rotation speed”) via the motor ECU 72. A signal representing (referred to as "Nm2") is input.

The MG1 rotation speed Nm1 is calculated by the motor ECU 72 based on "the output value of the resolver 96 provided in the first motor-generator MG1 and outputting the output value corresponding to the rotation angle of the rotor of the first motor-generator MG1". ing. Similarly, the MG2 rotation speed Nm2 is calculated by the motor ECU 72 based on "the output value of the resolver 97 provided in the second motor-generator MG2 and outputting the output value corresponding to the rotation angle of the rotor of the second motor-generator MG2". Has been done.

The PMECU 70 is adapted to input various output signals indicating the engine state via the engine ECU 73. The output signal representing the engine state includes the engine rotation speed Ne, the throttle valve opening TA, the cooling water temperature THW of the engine 20, and the like.

The motor ECU 72 is connected to the first inverter 61 and the second inverter 62. The motor ECU 72 sends an instruction signal to the first inverter 61 and the second inverter 62 based on a command from the PM ECU 70 (“MG1 command torque Tm1 * and MG2 command torque Tm2 *” described later). As a result, the motor ECU 72 controls the first generator motor MG1 by using the first inverter 61, and controls the second generator motor MG2 by using the second inverter 62.

The engine ECU 73 is connected to an engine actuator "throttle valve actuator 22a, fuel injection valve 23, ignition device 25, etc." and sends an instruction signal to these. Further, the engine ECU 73 is connected to an air flow meter 91, a throttle valve opening sensor 92, a cooling water temperature sensor 93, an engine rotation speed sensor 94, an air-fuel ratio sensor 95, and the like so as to acquire output signals generated by these. It has become.

The air flow meter 91 measures the amount of air sucked into the engine 20 per unit time, and outputs a signal indicating the amount of air (intake air flow rate) Ga.
The throttle valve opening sensor 92 detects the opening degree of the throttle valve 22 (throttle valve opening degree) and outputs a signal indicating the detected throttle valve opening degree TA.
The cooling water temperature sensor 93 detects the temperature of the cooling water of the engine 20 and outputs a signal indicating the detected cooling water temperature THW.

The engine rotation speed sensor 94 is adapted to generate a pulse signal each time the crankshaft 26 of the engine 20 rotates by a predetermined angle. The engine ECU 73 acquires the engine rotation speed Ne based on this pulse signal.
The air-fuel ratio sensor 95 is an exhaust collecting portion of the exhaust manifold 27 and is arranged at a position upstream of the three-way catalyst 29 on the upstream side. The air-fuel ratio sensor 95 is a so-called "faradaic current type wide area air-fuel ratio sensor". The air-fuel ratio sensor 95 detects the air-fuel ratio of the exhaust gas and outputs an output value corresponding to the detected air-fuel ratio (detected air-fuel ratio) Abyfs of the exhaust gas. The engine ECU 73 acquires the detected air-fuel ratio Abyfs by applying this output value to the look-up table.

The engine ECU 73 controls the engine 20 by sending an instruction signal to the "throttle valve actuator 22a, the fuel injection valve 23, and the ignition device 25" based on the signals acquired from these sensors and the command from the PM ECU 70. It has become like. The engine 20 is provided with a cam position sensor (not shown). The engine ECU 73 acquires the crank angle (absolute crank angle) of the engine 20 based on the intake top dead center of a specific cylinder based on the signals from the engine rotation speed sensor 94 and the cam position sensor. ..

(Operation: Driving force control)
Next, the operation of the hybrid vehicle 10 will be described. The processing described below is executed by the "CPU of the PM ECU 70 and the CPU of the engine ECU 73". However, in the following, in order to simplify the description, the CPU of the PMECU 70 is referred to as "PM", and the CPU of the engine ECU 73 is referred to as "EG".

The hybrid vehicle 10 sets a torque equal to "a torque determined according to the amount of accelerator operation by the user and required for the drive shaft 53 of the vehicle (that is, user-required torque)" as "the efficiency of the engine 20 is the best. By controlling the output torque of the engine 20 (engine output torque) and the output torque of the second power generation motor MG2, the drive shaft 53 is acted on.

At this time, in the hybrid vehicle 10, the output of the engine 20 satisfies the engine required output Pe *, and the engine operating point at which the efficiency of the engine 20 is maximized is "depending on the engine output torque Te and the engine rotation speed Ne. The engine 20 is operated at the "determined optimum engine operating point Pbt". The engine-requested output Pe * is acquired based on, for example, the user-requested output Pv * obtained by multiplying the user-requested torque by the vehicle speed SPD and the battery charge-requested output Pb * obtained based on the battery remaining capacity SOC.

Specifically, as shown in FIG. 3, the engine operating point at which the operating efficiency (fuel efficiency) of the engine 20 is the best when a certain output is output from the crankshaft 26 is set as the optimum engine operating point Pbt for each output. It has been obtained in advance by experiments and the like. These optimum engine operating points Pbt are plotted on a graph defined by the engine output torque Te and the engine rotation speed Ne, and a line formed by connecting these plots is obtained as the optimum engine operating line. .. The optimum engine operation line obtained in this way is shown by the solid line Lopt in FIG. In FIG. 3, each of the plurality of lines C0 to C3 shown by the broken line is referred to as a line connecting engine operating points capable of outputting the same output from the crankshaft 26 (referred to as "equal output line"). ).

The PM searches for the optimum engine operating point Pbt that can obtain an output equal to the engine required output Pe *, and sets the "engine output torque Te and engine rotation speed Ne" corresponding to the searched optimum engine operating point Pbt as the "target engine". It is determined as each of "output torque Te * and target engine rotation speed Ne *". For example, when the engine required output Pe * is equal to the output corresponding to the line C2, the engine output torque Te1 with respect to the intersection P1 (optimal engine operating point Pbt (= P1)) between the line C2 and the solid line Lopt is the target engine output torque Te *. The engine rotation speed Ne1 with respect to the intersection P1 (optimal engine operating point Pbt (= P1)) is determined as the target engine rotation speed Ne *.

The PM determines the engine output torque (Te1 in the example of FIG. 3) with respect to the optimum engine operating point Pbt as the target engine output torque Te *, and targets the engine rotation speed (Ne1 in the example of FIG. 3) with respect to the optimum engine operating point Pbt. Determined as the engine rotation speed Ne *. PM so that the engine 20 is operated at the optimum engine operating point Pbt (in other words, the engine output torque Te and the engine rotation speed Ne become the target engine output torque Te * and the target engine rotation speed Ne *). , Sends a command signal to the EG.

As a result, the EG changes the opening degree of the throttle valve 22 by the throttle valve actuator 22a, sets the fuel amount (sets the required fuel amount Ft), and sets the target engine output torque Te * and the target engine rotation speed Ne *. The engine 20 is controlled so as to be.

In the hybrid vehicle 10, the engine 20, the first generator motor MG1 and the second generator motor MG2 are controlled while being related to each other. The hybrid vehicle 10 can run in any of the EV mode and the HV mode, for example.

The EV mode is executed when the remaining capacity SOC is larger than the mode switching threshold value. The EV mode is a mode in which the vehicle 10 is driven by giving priority to the electric driving over the hybrid driving. In the electric traveling, the entire driving force of the vehicle 10 is generated from the second generator motor MG2 by driving the second generator motor MG2 without operating the engine 20 (this state is referred to as the "first operating state"). Also called.). In the hybrid driving, the driving force of the vehicle 10 is generated from both the engine 20 and the second generator motor MG2 by driving the engine 20 and the second generator motor MG2 (note that this state is referred to as "second". Also called "operating state").

The HV mode is a mode that is executed when the remaining capacity SOC becomes smaller than the mode switching threshold value during EV mode driving. The HV mode is a mode in which the vehicle 10 is driven by giving priority to the second driving state over the first driving state as compared with the EV mode. These modes are well known and are described, for example, in JP-A-2011-57115 and JP-A-2011-57116.

The basic contents of control in the HV mode are, for example, Japanese Patent Application Laid-Open No. 2009-126450 (US Patent No. US2010 / 0241297) and Japanese Patent Application Laid-Open No. 9-308012 (US filing date: March 10, 1997). It is described in detail in US Pat. No. 6,131,680), etc.

Further, the hybrid vehicle 10 performs intermittent operation in which the operation of the engine 20 is intermittently stopped. For example, the hybrid vehicle 10 stops the operation of the engine 20 when the engine required output Pe * is smaller than the engine stop threshold value and the engine 20 cannot be operated efficiently. Further, the hybrid vehicle 10 starts the operation of the engine 20 when the engine required output Pe * becomes larger than the engine start threshold value while the operation of the engine 20 is stopped and the engine 20 can be operated efficiently.

In the hybrid vehicle 10 in which the driving force control is executed as described above, the engine 20 is frequently not operated due to the intermittent operation of the engine 20 or the like.

<Outline of operation>
The EG controls the fuel injection valve 23 and executes fuel injection (hereinafter, referred to as “active injection”) for learning the injection characteristics of the fuel injection valve 23 and detecting an abnormality regarding partial lift injection. The EG is divided into, for example, one partial lift injection (learning fuel injection (learning partial lift injection)) and one full lift injection as active fuel injection, and the engine 20 (combustion chamber CC of the cylinder). ) Is executed (injection twice in the intake stroke).

As described above, in the hybrid vehicle 10, the engine 20 is frequently not operated due to intermittent operation or the like. Therefore, in the hybrid vehicle 10, the opportunity for active injection (the opportunity for learning the injection characteristics of the fuel injection valve 23 and detecting an abnormality) may be reduced. Therefore, the PM controls the operation of the engine 20 as follows in order to increase the number of fuel injections per unit time.

The PM is an equal output line (example of FIG. 3) corresponding to the engine required output Pe * required for the engine 20 when the active injection execution condition (referred to as “active injection execution condition”) described later is satisfied. In line C2), the engine 20 operates at an operating point Pg (Pg = Pg1) shifted to a side where the engine rotation speed Ne is larger than the optimum engine operating point Pbt (P1 in the example of FIG. 3). To control. The operating point Pg is also referred to as a "learning operating point Pg".

Specifically, PM determines the engine output torque Te2 with respect to the learning operating point Pg (= Pg1) as the target engine output torque Te *, and the engine rotation speed Ne2 (Ne2) with respect to the learning operating point Pg (= Pg1). > Ne1) is determined as the target engine rotation speed Ne *. In the PM, the engine 20 is operated at the learning operating point Pg (= Pg1) (in other words, the engine output torque Te and the engine rotation speed Ne are the target engine output torque Te * and the target engine rotation speed Ne *. ), Send a command signal to the EG.

As a result, the EG changes the opening degree of the throttle valve 22 by the throttle valve actuator 22a, sets the fuel amount (sets the required fuel amount Ft), and sets the target engine output torque Te * and the target engine rotation speed Ne *. The engine 20 is controlled so as to be.

The EG is an active injection (for example, two intake strokes) in which the required amount of fuel per cylinder is divided into one partial lift injection (learning fuel injection) and one full lift injection. Injection) is executed by the fuel injection valve 23.

(Learning of injection characteristics of fuel injection valve and detection of abnormalities)
The EG learns the injection characteristics of the fuel injection valve 23 and detects abnormalities (“OBD (On-board diagnostics) detection” based on the induced electromotive force generated by the valve closing operation of the fuel injection valve 23 (valve body (needle valve)). Also called.) Is executed.

As shown in FIG. 4, in the fuel injection valve 23, after the injection pulse is set (changed) from on (ON) to off (OFF), the injector- (minus) terminal voltage changes due to the induced electromotive force.

When the fuel injection valve 23 is closed, the change speed of the valve body changes relatively significantly, so that the change characteristic of the injector- (minus) terminal voltage changes, and a voltage inflection point appears. Therefore, it is possible to detect the valve closing timing by the timing at which the voltage inflection point of the injector- (minus) terminal voltage appears.

In a partial lift state in which the lift amount of the valve body of the fuel injection valve 23 does not reach the full lift position, the valve closing timing (for example, the time between a predetermined timing and the valve closing timing) and the injection amount of the fuel injection valve 23 There is a correlation between. Utilizing such a correlation, the injection pulse of the partial lift injection is corrected.

For example, the EG causes the fuel injection valve 23 to execute active injection a predetermined number of times required for learning the injection characteristics, so that a predetermined reference timing tb (for example, when the energization of the injection pulse during partial lift is turned off, etc.) ) To the time Tm (inflection point time Tm) from the time when the inflection point of the injector- (minus) terminal voltage appears to the time when the fuel injection valve 23 (needle valve) is closed) is acquired for a predetermined number of times. To do. Then, the average value of the inflection point time Tm (average inflection point time Tmv) is acquired as a learning value. Then, based on the learned value, a process of correcting the injection pulse of the partial lift injection is performed for each cylinder.

Further, the EG executes abnormality detection of the fuel injection valve 23 by determining whether or not the inflection point time Tm acquired when the fuel injection valve 23 performs partial lift injection is out of a predetermined range. For example, when the EG detects that the inflection point time Tm is out of the predetermined range more than a predetermined number of times, it determines that the fuel injection valve 23 is abnormal. In this case, the EG prohibits the correction of the injection pulse.

As described above, according to the embodiment of the present invention, the learning operating point shifted from the optimum engine operating point Pbt to the side where the engine rotation speed Ne increases on the equal output line corresponding to the engine required output Pe *. The engine 20 is operated with Pg. As a result, the engine rotation speed Ne can be increased, so that the number of injections per unit time when performing active injection can be increased. Therefore, in the embodiment of the present invention, the parameters required for the injection characteristic learning and abnormality detection of the fuel injection valve 23 can be acquired at an early stage, so that the injection characteristic learning and abnormality detection can be completed at an early stage.

<Specific operation>
The PG executes the routine shown by the flowchart in FIG. 5 every time a predetermined time elapses.

Therefore, at a predetermined timing, the PG starts the process from step 500 in FIG. 5 and proceeds to step 505 to determine whether or not the engine 20 (internal combustion engine) is in operation.

If the engine 20 is not in operation, the PG determines "No" in step 505, proceeds to step 595, and temporarily ends this routine.

On the other hand, when the engine 20 is in operation, the PG determines “Yes” in step 505 and proceeds to step 510 to learn the injection characteristics and complete the abnormality detection flag Xf (hereinafter, simply “flag Xf”). It is determined whether or not the value of (called) is set to "0".

When the value of the flag Xf is "1", it indicates that the injection characteristic learning and abnormality detection (abnormality determination) of the fuel injection valve 23 have been completed. When the value of the flag Xf is "0", it means that the injection characteristic learning and abnormality detection (abnormality determination) of the fuel injection valve 23 have not been completed. The value of the flag Xf is set to "0" in an initial routine (not shown) that is executed separately.

When the value of the flag Xf is set to "1", the PG determines "No" in step 510, proceeds to step 595, and temporarily ends this routine. On the other hand, when the value of the flag Xf is set to "0", the PG determines "Yes" in step 510 and proceeds to step 515 to determine whether or not the active injection execution condition is satisfied. To do.

The active injection execution condition is satisfied when all of the conditions 1 and 2 described below are satisfied.
Condition 1: The cooling water temperature THW is equal to or higher than a predetermined threshold water temperature Tth.
Condition 2: The load factor is equal to or higher than a predetermined value.
The load factor (KL) is, for example, the air filling factor, the amount of air taken in by the cylinder of interest in one intake stroke is Mc [g], the air density is ρ [g / L]), and the displacement of the engine 20. Is Lv [L], and the number of cylinders of the engine 20 is "4", it is calculated by the following equation.
KL = {Mc / (ρ × Lv / 4)} × 100 (%)

If the active injection execution condition is not satisfied, the PG determines "No" in step 515, proceeds to step 595, and temporarily ends this routine.

On the other hand, when the active injection execution condition is satisfied, the PG determines “Yes” in step 515, performs the processes of steps 520 to 530 described below in order, and then proceeds to step 535.

Step 520: The PG determines the learning operating point Pg described above. That is, the PG is an operating point (learning) shifted to a side where the engine rotation speed Ne is larger than the optimum engine operating point Pbt on the equal output line corresponding to the engine required output Pe * required for the engine 20 (internal combustion engine). The operating point Pg) is determined.
Step 525: In the PG, the engine 20 is operated at the learning operating point Pg (in other words, the engine output torque Te and the engine rotation speed Ne corresponding to the learning operating point Pg are the target engine output torque Te * and A command signal is sent to the EG (so that the target engine speed is Ne *). As a result, the EG determines the engine output torque Te corresponding to the learning operating point Pg as the target engine output torque Te *, and determines the engine rotation speed Ne corresponding to the learning operating point Pg as the target engine rotation speed Ne *. To do.

Then, the EG changes the opening degree of the throttle valve 22 by the throttle valve actuator 22a, sets the fuel amount (sets the required fuel amount Ft), and becomes the target engine output torque Te * and the target engine rotation speed Ne *. As such, the engine 20 is controlled.

Further, the EG controls the fuel injection valve 23 and injects the fuel for the required fuel amount per cylinder by dividing it into one partial lift injection (learning fuel injection) and one full lift injection. Active injection (intake stroke twice injection) is executed. Then, the EG executes the above-mentioned injection characteristic learning and injection valve abnormality detection.

When the PG proceeds to step 530, it determines whether or not the injection characteristic learning and abnormality detection (abnormality determination) of the fuel injection valve 23 have been completed. If the injection characteristic learning and abnormality detection (abnormality determination) of the fuel injection valve 23 have not been completed, the PG determines "No" in step 530, proceeds to step 595, and temporarily ends this routine.

On the other hand, when the injection characteristic learning and abnormality detection (abnormality determination) of the fuel injection valve 23 are completed, the PG determines "Yes" in step 530, proceeds to step 535, and sets the value of the flag Xf. After setting to "1", the process proceeds to step 595, and this routine is temporarily terminated.

<Modification example>
Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention can be adopted. For example, in the above embodiment, the engine 20 may be a dual injection type internal combustion engine.

Further, in the above-described embodiment, the following process may be executed instead of the step 520 shown in FIG. The PG determines the increased engine required output (raised engine required output) in which the engine output is increased from the normal engine required output as the engine required output Pe *, and determines the optimum engine operating point Pbt. For example, suppose that the equal output line corresponding to the normal engine required output is line C2 and the equal output line corresponding to the increased engine required output is line C1 (see FIG. 3). In this case, the PG determines the intersection P2 of the line C1 and the solid line Lopt as the optimum engine operating point Pbt. That is, the PG raises the normal engine required output and shifts the optimum engine operating point Pbt to the side where the engine rotation speed Ne increases.

As a result, in step 525, the PG sends a command signal to the EG so that the engine 20 is operated at the optimum engine operating point Pbt (= P2). As a result, the EG determines the engine output torque Te3 with respect to the optimum engine operating point Pbt (= P2) as the target engine output torque Te *, and the engine rotation speed Ne3 (Ne3> Ne1) with respect to the optimum engine operating point Pbt (= P2). Is determined as the target engine rotation speed Ne *.

Then, the EG changes the opening degree of the throttle valve 22 by the throttle valve actuator 22a, sets the fuel amount (sets the required fuel amount Ft), and becomes the target engine output torque Te * and the target engine rotation speed and Ne *. As such, the engine 20 is controlled. In this case, the PG further shifts the optimum engine operating point Pbt (= P2) to the side where the engine rotation speed Ne increases (for example, the learning operating point Pg (= Pg2)) on the equal output line. The engine 20 may be operated at the shifted learning operating point Pg2.

Further, in the above-described embodiment and modification, the engine 20 may be controlled so that the intermittent operation of the engine 20 (intermittent operation of the engine) is prohibited when the active injection execution condition is satisfied. In the above-described embodiment, when the active injection execution condition is satisfied, the engine 20 may be prohibited from intermittent operation instead of being operated at the learning operating point Pg. ..

10 ... hybrid vehicle, 20 ... engine, 22 ... throttle valve, 22a ... throttle valve actuator, 23 ... fuel injection valve, 26 ... crankshaft, 30 ... power distribution mechanism, 31 ... planetary gear device, 50 ... driving force transmission mechanism, 53 ... Drive shaft, 70 ... Power management ECU, 73 ... Engine ECU

Claims (1)

An internal combustion engine and a hybrid vehicle equipped with a fuel injection valve for injecting fuel into the internal combustion engine and an electric motor.
The hybrid vehicle
A power transmission mechanism that connects the drive shaft of the vehicle and the internal combustion engine so as to be able to transmit torque, and also connects the drive shaft and the electric motor so that torque can be transmitted.
By controlling the output torque of the internal combustion engine and the output torque of the electric motor by operating the internal combustion engine, a torque equal to the user-required torque, which is the torque required for the drive shaft determined according to the accelerator operation amount of the user, is controlled. Intermittent engine operation that controls the drive shaft to act on it, stops the operation of the internal combustion engine when a predetermined engine operation stop condition is satisfied, and starts the internal combustion engine when the predetermined engine start condition is satisfied. And execute
When the operation of the internal combustion engine is executed, it is the operating point of the internal combustion engine defined by the output torque of the internal combustion engine and the engine rotation speed of the internal combustion engine, and is the engine output required for the internal combustion engine. A driving force that controls the internal combustion engine to operate at the optimum engine operating point, which is the operating point specified based on the efficiency of the internal combustion engine, from the output line connecting the operating points corresponding to the required engine output. Control unit and
Active fuel including partial lift injection for learning necessary for causing the fuel injection valve to execute partial lift injection at a predetermined injection timing and to learn the injection characteristics of the fuel injection valve and detect an abnormality at the time of partial lift injection. A fuel injection valve control unit that controls injection to be executed by the fuel injection valve,
With
The driving force control unit
When the active fuel injection is performed
To operate the internal combustion engine on the equal output line at a learning operating point in which the optimum engine operating point is shifted to the side where the engine rotation speed increases from the engine rotation speed corresponding to the optimum engine operating point.
Using the raised required engine output as the required engine output, operating the internal combustion engine and
Prohibiting intermittent operation of the engine,
Configured to perform at least one of
Hybrid vehicle.

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