JP2004346834A - Engine start controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine start controlling device capable of starting an engine in a short time while reducing the load on a storage device while reducing the output torque of a motor in starting the engine. <P>SOLUTION: This engine start controlling device for starting the engine 2 by the motor 3, comprises a rotating frequency sensor NeS for detecting a rotating frequency of a crank shaft 26, a timer TM for detecting an elapsed time from the start, and the motor ECU 22 where a set pattern is determined to increase the rotating frequency of the crank shaft 26 at an equiangular acceleration to the elapsed time from the start of the starting, and the motor torque is applied to the motor ECU 22 to increase the rotating frequency of the crank shaft 26 at the equiangular acceleration of the set pattern determined in the motor ECU 22. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an engine start control device for a vehicle that starts an engine as a drive source by a motor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a hybrid vehicle including an engine and a motor as driving sources, a hybrid vehicle that controls output torque of the engine and the motor is known. For example, Patent Literature 1 discloses a technique of gradually increasing the engine speed and gradually decreasing the output torque of the motor when starting the engine when the vehicle is stopped.
[0003]
[Patent Document 1]
JP-A-2000-186585 (paragraph number 0028, FIG. 8)
[0004]
[Problems to be solved by the invention]
By the way, when starting the engine, it is conceivable that the output torque of the motor is transmitted to the engine, and the rotation speed of the engine is increased early so as to shorten the engine start time.
However, in order to increase the engine speed early, it is preferable to increase the output torque of the motor to be applied. However, in this case, the power consumption of the motor increases, and the power storage device that supplies power to the motor is required. There is a problem that the burden increases.
[0005]
The present invention has been made in view of such circumstances, and when starting an engine, it is possible to start the engine in a short time while suppressing the output torque of the motor to reduce the load on the power storage device. It is an object to provide a control device.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention described in claim 1 is an engine start control device that starts an engine (for example, the engine 2 in the embodiment) by a motor (for example, the motor 3 in the embodiment). A rotation speed detection unit (for example, a rotation speed sensor NeS in the embodiment) that detects the rotation speed of the shaft (for example, the crankshaft 26 in the embodiment), and an elapsed time detection unit (for example, the rotation time sensor NeS in the embodiment) , A timer TM in the embodiment, and determination means (for example, the motor ECU 22 in the embodiment) for determining a setting pattern in which the number of revolutions of the crankshaft increases at a constant angular acceleration with respect to the elapsed time from the start of the start. A motor so that the rotational speed of the crankshaft is increased by the constant angular acceleration of the set pattern determined by the determining means. Start control means for applying a torque (for example, a motor ECU22 in the embodiment) and further comprising a.
[0007]
According to this invention, based on the setting pattern determined by the determining means, the rotation speed detected by the rotation speed detecting means and the elapsed time from the start detected by the elapsed time detecting means, The starting control means applies a motor torque so that the rotation speed of the crankshaft increases at a constant angular acceleration. The setting pattern is set such that the rotation speed can be increased at a constant angular acceleration within a range of a torque that can be output from the motor. Thus, the rotation speed of the crankshaft can be increased to the rotation speed during normal driving in substantially the same time as when the maximum output torque of the motor is applied to the engine when the engine is started. Therefore, the rotation speed of the crankshaft can be quickly increased to the rotation speed during normal driving without imposing an excessive burden on the motor or the power storage device that supplies power to the motor.
[0008]
According to a second aspect of the present invention, there is provided a temperature detecting unit for detecting a temperature of a power storage device for supplying electric power to the motor or an engine temperature (for example, a battery temperature sensor according to the embodiment). TbS, an engine coolant temperature sensor TwS), and the determining means determines the value of the constant angular acceleration of the set pattern according to the temperature detected by the temperature detecting means.
[0009]
According to the present invention, the value of the constant angular acceleration is determined by the determining unit in accordance with the temperature of the power storage device detected by the temperature detecting unit and the engine temperature, so that the rotational speed of the crankshaft can be increased. Since the accompanying temperature change of the power storage device and the engine temperature can be suppressed, and the required output to the power storage device due to the increase in the number of revolutions can be suppressed low, the protection for the engine and the power storage device is further enhanced. The engine can be started.
[0010]
The invention described in claim 3 is the invention according to claim 1 or 2, wherein decompression means (for example, decompression means 28 in the embodiment) for invalidating the compression action of the compression process of the engine. And a state detecting means (for example, the engine ECU 21 in the embodiment) for detecting a state of the decompression means. When the state detection means detects an abnormality of the decompression means at the time of cranking, the motor to be applied is applied. A torque obtained by adding a torque required for a compression process of the engine to the torque is applied until the crankshaft rises to a required minimum rotation speed.
[0011]
According to the present invention, if the state detecting means does not detect an abnormality of the decompression means, the decompression means is operated at the time of transition from the time of cranking the engine to the time of ignition to reduce the torque fluctuation at the time of the transition. In addition to being able to absorb, even when an abnormality of the decompression means is detected by the state detection means, the transition from the cranking time to the ignition time is performed by applying the necessary torque during the cranking. Is smooth, and the startability is improved.
[0012]
The invention described in claim 4 is the invention according to claim 1 or claim 2, wherein the applied motor torque is applied to the engine compression process until the crankshaft rises to a required minimum rotation speed. It is characterized in that a torque obtained by adding a necessary torque is applied.
According to the present invention, by applying the necessary torque, the transition from the cranking to the ignition can be performed smoothly, and the startability is improved.
[0013]
The invention described in claim 5 is the invention according to any one of claims 1 to 4, wherein the crankshaft and the motor drive shaft are connected to a pulley (for example, a pulley 31 in the embodiment). , 32) and a belt (for example, the belt 33 in the embodiment) wound around the pulley (see, for example, the power transmission unit 30 in the embodiment).
[0014]
According to the present invention, since the torque applied by the motor to the engine is suppressed, the slippage of the belt and the noise generated by the belt can be naturally suppressed. Therefore, it is not necessary to apply excessive tension to the belt, so that the cost and life of the belt can be reduced, and the fuel efficiency can be improved.
[0015]
The invention described in claim 6 is the invention according to any one of claims 1 to 5, wherein the target torque is TB, the moment of inertia of the engine is I, and the friction torque of the engine is Tf. Calculating the target torque TB by the following equation, where Ne is the rotation speed of the crankshaft, Pp is the pumping loss, Kt is a predetermined coefficient, ωA and ωB are the angular velocities for each of the elapsed times tA and tB from the start of the start. Features.
TB = I × (ωB−ωA) / (tB−tA) + Tf + Pp × Kt / Ne
[0016]
According to the present invention, since the target torque is calculated in consideration of the pumping loss and the friction torque, the accuracy of the target torque TB applied to the engine can be increased, and the engine speed can be more efficiently increased. Can be done.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an engine start control device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a hybrid vehicle 1 including an engine start control device according to an embodiment of the present invention.
[0018]
The hybrid vehicle 1 uses an engine 2 and a motor 3 as drive sources, and can transmit power from these drive sources to drive wheels 14 via an automatic transmission 13.
[0019]
The engine 2 is provided with a pair of intake valves 8 and a pair of exhaust valves 17 for each cylinder. The intake valves 8 and the exhaust valves 17 are opened and closed by an intake valve actuator 9 and an exhaust valve actuator 18.
An intake pipe 7 is connected to an intake valve 8 of the engine 2, and a throttle valve 4 is disposed in the intake pipe 7. A throttle actuator 5 is connected to the throttle valve 4, and the throttle actuator 5 controls an opening degree θTH of the throttle valve 4 according to a control signal from an engine ECU 21 described later.
[0020]
A fuel injection valve 6 for injecting fuel into the engine 2 is provided downstream of the intake pipe 7 on the throttle valve 4 side. A high-pressure pump (not shown) is connected to the fuel injection valve 6, and gasoline as fuel is pressurized to a high pressure by the high-pressure pump and injected from the fuel injection valve 6. As a result, fuel is mixed with fresh air supplied through the throttle valve 4 and flows into a combustion chamber (not shown) of the engine 2 through the intake valve 8.
[0021]
On the other hand, an exhaust pipe 19 composed of an exhaust manifold or the like is connected downstream of the exhaust valve 17. The exhaust pipe 19 is provided with a three-way catalyst 20 for purifying exhaust gas.
A decompression means 28 is connected to the exhaust valve 17, and decompression is performed by the operation of the decompression means 28.
[0022]
In the present embodiment, the engine 2 and the motor 3 are connected to pulleys 31 and 32 directly connected to a crankshaft 26 of the engine 2 and a drive shaft 27 of the motor 3, respectively, and a belt is wound around the pulleys 31 and 32. 33 are connected by power transmission means 30.
[0023]
The motor 3 is composed of, for example, a three-phase AC motor, and is connected to a battery 16 via a PDU (power drive unit) 15.
The motor 3 has the functions of a motor and a generator. When the motor 3 is operated as a motor, the electric power of the battery 16 is supplied via the PDU 15 to be driven. When the motor 3 is operated as a generator, the electric power generated by the motor 3 converts the PDU 15. The battery 16 is charged through the battery.
For example, a battery in which a plurality of nickel-hydrogen batteries are connected in series and a plurality of modules are connected in series can be used as the battery 16.
[0024]
In the present embodiment, an engine ECU 21, a motor ECU 22, a battery ECU 23, and a transmission ECU 24 for controlling the engine 2, the motor 3, the battery 16, and the transmission 13 are provided, respectively.
The engine ECU 21 generates an ignition signal Ig from an ignition switch (not shown), a throttle opening signal θth from a throttle opening sensor provided on a throttle pedal (not shown), a rotation speed Ne from a rotation speed sensor NeS of the crankshaft 26, and the engine 2 The engine coolant temperature Tw from the coolant temperature sensor TwS, and the signal pulse CYL at a predetermined crank angle position of the cylinder from the cylinder discriminating sensor CylS are input, respectively, and communicated with the other ECUs 22 to 24 to obtain the injection amount of the fuel injection valve 6. , The opening of the throttle valve 4, the opening of the exhaust valve 17, the ignition timing, and the like are set and transmitted to the fuel injection valve 6 and the like.
[0025]
The motor ECU 22 communicates with the other ECUs 21, 23, and 24 to set a normal torque command value TQ for driving the motor 3 and a starting torque command value for starting the engine 2 and transmit them to the PDU 15. Here, the starting torque command value at the time of the starting is a set pattern (the rotational speed Ne of the crankshaft 26 increases at a constant angular acceleration with respect to the elapsed time from the start of the engine input which is input by a signal from the timer TM). (See FIG. 3). This will be described later.
[0026]
The battery ECU 23 receives the battery current Ib, the inter-terminal voltage Vb, and the battery temperature Tb from the current sensor IbS, the voltage sensor VbS, and the battery temperature sensor TbS of the battery 16, respectively, and communicates with the other ECUs 21, 22, and 24. The transmission ECU 24 receives a position command signal (not shown) and a hydraulic signal of the transmission 13 from a shift lever or the like (not shown), and communicates with the other ECUs 21 to 23 to set a hydraulic command value and the like to set the transmission 13 Send to
[0027]
The operation of the engine start control device configured as described above will be described. FIG. 2 is a flowchart showing a motor torque calculation process during engine start control. First, in step S12, various temperature data is acquired. The various temperature data are the temperature Tb of the battery 16 detected by the battery temperature sensor TbS, the water temperature of the engine 2 detected by the engine water temperature sensor TwS, and the like. In step S14, the setting pattern relating to the time of the engine speed is corrected based on the acquired temperature data. In other words, the value of the constant angular acceleration of the set pattern is determined according to the acquired temperature data.
[0028]
FIG. 3 is a graph showing a setting pattern relating to the time of the engine speed. The setting patterns LE-1 to LE-3 shown in the drawing are set so that the rotation speed Ne of the crankshaft 26 increases at a constant angular acceleration to the rotation speed during normal driving with respect to the elapsed time from the start of the start. . Although FIG. 3 shows three setting patterns LE-1 to 3 as representatives among the setting patterns, the setting patterns are not limited to only LE-1 to LE-3.
[0029]
In the above-described step S14, among the setting patterns, one having the value of the equiangular acceleration (for example, the setting pattern LE-1) is selected according to various temperature data.
Then, in step S16, it is determined whether the decompression function is normal. If the determination result is YES, the process proceeds to step S18, and if the determination result is NO, the process proceeds to step S20.
[0030]
In step S18, the target torque of the motor 3 is calculated. This will be described with reference to FIG. FIG. 4 is a graph showing the relationship between the rotation speed of the crankshaft and the time of the motor torque. As shown in the figure, according to the setting pattern LE-X (in this case, X = 1) corrected by the acquired temperature data, the target torque is set so that the rotation speed of the crankshaft 26 increases at a constant angular acceleration. Is calculated. That is, from the rotation speed of the crankshaft 26 detected by the rotation speed sensor NeS and the elapsed time from the start of the start detected by the timer TM (tA in this case), after a predetermined time Δt (tB in this case). The rotational speed of the crankshaft 26 is retrieved from the set pattern LE-1, and the torque (target torque) necessary for increasing the rotational speed is calculated by the following equation.
[0031]
TB = I × (ωB−ωA) / (tB−tA) + Tf + Pp × Kt / Ne
[0032]
Here, the target torque is TB, the moment of inertia of the engine is I, the friction torque of the engine is Tf, the rotational speed of the crankshaft is Ne, the pumping loss is Pp, the predetermined coefficient is Kt, and the elapsed time from the start of the start. The angular velocities for each of tA and tB are ωA and ωB. As described above, since the target torque is calculated in consideration of the pumping loss and the friction torque, the accuracy of the target torque TB applied to the engine 2 can be improved, and the rotation speed of the engine 2 can be more efficiently increased. Can be done.
[0033]
Here, when the decompression function of the decompression means 28 is normal, the rotation speed of the crankshaft 26 is equal to or higher than a specified rotation speed (the rotation speed for determining whether the engine 2 is in the cranking state or the ignition state). If it does, the decompression means 28 is operated. Accordingly, when the rotation speed of the crankshaft 26 is equal to or less than the specified rotation speed, a preset upper limit torque is output from the motor 3 and when the rotation speed of the crankshaft 26 becomes higher than the specified rotation speed. , The target torque is output from the motor 3. As a result, the required torque immediately after the start of the engine 2 can be secured, and the torque fluctuation at the time of transition from cranking to ignition can be absorbed, so that the transition from cranking to ignition can be performed smoothly. And startability is improved.
[0034]
On the other hand, in step S20, it is determined whether the rotation speed Ne detected by the rotation speed sensor NeS is equal to or less than a specified rotation speed. If the result of this determination is YES, it can be determined that cranking has occurred. In step S22, a specified torque that takes into account the torque required for the compression process of the engine 2 is applied, and a series of processing ends. I do. If the result of the determination in step S20 is NO, it can be determined that the engine 2 has shifted at the time of ignition. Therefore, the process proceeds to step S18 without applying the specified torque, and after calculating the target torque described above, A series of processing ends.
[0035]
As described above, even when the abnormality of the decompression means 28 is detected, by applying the specified torque as in step S22, the transition from the time of cranking to the time of ignition becomes smooth, and the startability is improved.
[0036]
FIG. 5 is a graph illustrating the rotation speed of the crankshaft 26 and the output time of the battery 16 in the embodiment and the comparative example. The comparative example shows a case where the output torque of the motor 3 is set to be applied to the engine 2 to the maximum. In the figure, LE and LE 'indicate the rotation speed of the crankshaft 26 in the embodiment and the comparative example, respectively, and LB and LB' indicate the output of the battery 18 in the embodiment and the comparative example, respectively.
[0037]
When the maximum output torque of the motor 3 is applied to the engine 2 at the time of starting the engine 2 as in the comparative example, the rotation speed of the crankshaft 26 sharply increases at the beginning of the application, but the rotation speed is increased during normal driving. When the rotation speed rises to near the rotation speed, the rise degree converges. For this reason, the time required to shift to the rotation speed during normal driving is substantially equal to the case where the rotation speed is increased at a constant angular acceleration as in the present embodiment. In addition, in the case of the present embodiment, since the degree of increase in the rotation speed of the crankshaft 26 at the start of starting is suppressed as compared with the case of the comparative example, the output required for the battery 16 is smaller than that of the comparative example. It can be kept low. Accordingly, the rotation speed of the crankshaft 26 can be quickly increased to the rotation speed at the time of normal driving without imposing an excessive load on the motor 3 and the battery 16 for supplying power to the motor 3.
[0038]
Further, since the torque applied by the motor 3 to the engine 2 is suppressed, when the output torque of the motor 3 is transmitted to the engine 2 via the belt 23, the slip of the belt 23 and the noise generated by the belt 23 are generated. Can be naturally suppressed. As a result, it is not necessary to apply excessive tension to the belt 23 for suppressing the generated noise, and the cost and life of the belt 23 can be reduced, and the fuel efficiency can be improved.
[0039]
It should be noted that the application of the present invention is not limited to the above-described embodiment. For example, a configuration in which the engine 2 and the motor 3 are not directly connected by the above-described power transmission means 30 but may be a configuration in which the engine 2 and the motor 3 are directly connected. Further, even when the decompression unit 28 is not provided, the present invention can be applied by performing the processing of step S20 after step S14.
[0040]
【The invention's effect】
As described above, according to the first aspect of the present invention, the rotation speed of the crankshaft during normal driving is substantially the same as when the output torque of the motor is applied to the engine at the maximum when the engine is started. Can be increased up to the number of rotations. Therefore, the rotation speed of the crankshaft can be quickly increased to the rotation speed during normal driving without imposing an excessive burden on the motor or the power storage device that supplies power to the motor.
[0041]
According to the invention described in claim 2, it is possible to start the engine while further protecting the engine and the power storage device.
According to the invention described in claim 3, if the state detecting means does not detect an abnormality of the decompression means, the torque fluctuation at the time of the transition can be absorbed, and the decompression means can be absorbed by the state detecting means. When the abnormality is detected, the transition from the cranking to the ignition can be performed smoothly, and the startability is improved.
[0042]
According to the invention described in claim 4, it is possible to smoothly shift from the time of cranking to the time of ignition, and the startability is improved.
According to the invention described in claim 5, the slippage of the belt and the sound generated by the belt can be naturally suppressed, and it is not necessary to apply excessive tension to the belt to suppress the generated sound. The belt can be reduced in cost, prolonged in service life, and improved in fuel efficiency.
[0043]
According to the invention described in claim 6, the accuracy of the target torque TB applied to the engine can be improved, and the rotation speed of the engine can be more efficiently increased.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a hybrid vehicle including an engine start control device according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating a motor torque calculation process during engine start control.
FIG. 3 is a graph showing a setting pattern relating to time of a rotation speed of a crankshaft.
FIG. 4 is a graph showing a relationship between a rotation speed of a crankshaft and a time of a motor torque.
FIG. 5 is a graph showing the relationship between the number of revolutions of a crankshaft and the time of battery output in an example and a comparative example.
[Explanation of symbols]
1 Hybrid vehicle 2 Engine 3 Motor 21 Engine ECU
22 Motor ECU
26 crankshaft 28 decompression means 30 power transmission means

Claims (6)

In an engine start control device that starts an engine by a motor, a rotation speed detection unit that detects a rotation speed of a crankshaft, an elapsed time detection unit that detects an elapsed time from a start, and a rotation speed of the crankshaft from the start of the start. Determining means for determining a setting pattern that increases at an equal angular acceleration with respect to the elapsed time, wherein the motor torque is increased such that the rotational speed of the crankshaft increases at the equal angular acceleration of the setting pattern determined by the determining means. An engine start control device, comprising: a start control unit for applying the voltage. Temperature detecting means for detecting a temperature of a power storage device or an engine temperature for supplying electric power to the motor, wherein the determining means determines a value of the constant angular acceleration of the set pattern in accordance with the temperature detected by the temperature detecting means. The engine start control device according to claim 1, wherein A decompression means for disabling a compression operation in the compression process of the engine, and a state detection means for detecting a state of the decompression means, wherein the state detection means detects an abnormality of the decompression means at the time of cranking. 3. The motor according to claim 1, wherein a torque obtained by adding a torque required for an engine compression process to the applied motor torque is applied until the crankshaft rises to a required minimum rotation speed. Engine start control device. 3. A torque obtained by adding a torque required for an engine compression process to the applied motor torque to the applied motor torque until the crankshaft rises to a required minimum rotation speed. An engine start control device according to any one of the preceding claims. The engine start according to any one of claims 1 to 4, wherein the crankshaft and the motor drive shaft are connected by power transmission means including a pulley and a belt wound around the pulley. Control device. The target torque is TB, the moment of inertia of the engine is I, the friction torque of the engine is Tf, the rotational speed of the crankshaft is Ne, the pumping loss is Pp, the predetermined coefficient is Kt, and the elapsed time from the start of the start tA, tB. The engine start control device according to any one of claims 1 to 5, wherein the target torque TB is calculated by the following equation, with the angular velocities of the respective motors being ωA and ωB.
TB = I × (ωB−ωA) / (tB−tA) + Tf + Pp × Kt / Ne

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