JP2008038875A - Hybrid system for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide favorable drivability without change delay of a compression ratio by finishing change of the compression ratio to that corresponding to driving conditions before operation of an engine, during starting by output of a motor. <P>SOLUTION: The hybrid vehicle is provided with a power source comprised by combining the engine E and the motor MG operated by electric power of a battery BT, and a variable compression ratio capable of raising and lowering the compression ratio is provided in the engine E. At starting, drive wheels W are driven by the output of the motor MG, motoring of the engine E is carried out, the compression ratio of the engine E during motoring is changed to that corresponding a driving condition of the vehicle, and then, an ignition system of the engine E is operated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle that includes a power source that is a combination of an engine and a motor that is operated by electric power of a battery, and in which the engine is provided with a variable compression ratio device that can change its compression ratio. It relates to the improvement of the hybrid system.

Patent Document 1 discloses a hybrid vehicle that includes a power source that is a combination of an engine and a motor that is operated by battery power, and in which the engine is provided with a variable compression ratio device that can change the compression ratio. As is already known. Various engine variable compression ratio devices are already known as disclosed in Patent Documents 2 to 5.
JP 2004-44433 A JP 2005-54619 A JP-A 64-15438 JP-A-9-228858 JP-A-60-142020

  When starting a hybrid vehicle, the engine and motor outputs are usually summed and transmitted to the drive wheels in order to increase the drive force of the drive wheels. In this case, the engine compression ratio is immediately determined according to the operating conditions at that time. In order to obtain good drivability, it is desirable to make it compatible with.

  However, since many of the general variable compression ratio devices use the inertia of the piston in the engine operating state to change the compression ratio, even if a command to change the compression ratio is given, the compression ratio is not changed unless the engine is operated. No changes are made.

  However, when the conventional hybrid vehicle is started, the engine is started and the motor is operated. Therefore, the compression ratio of the engine is changed after the start, and a delay in changing the compression ratio cannot be denied.

  The present invention has been made in view of such circumstances, and during the start by the output of the motor, before the operation of the engine, the change of the compression ratio to the one corresponding to the operating condition is completed, It is an object of the present invention to provide a hybrid system for a hybrid vehicle that can obtain good drivability without delay in changing the compression ratio.

  In order to achieve the above object, a hybrid system of a hybrid vehicle of the present invention includes a power source that is a combination of an engine and a motor that is operated by electric power of a battery, and the compression ratio of the engine is changed in level. In a hybrid vehicle provided with a variable compression ratio device to obtain, at the time of starting, the driving wheel is driven by the motor output and the engine is motored, and the engine compression ratio corresponds to the driving condition of the vehicle during this motoring. The first feature is that the engine ignition device is operated after that.

  In addition to the first feature, the present invention has a second feature that the operating condition of the vehicle includes an engine throttle valve opening and a vehicle speed.

  Furthermore, in addition to the first feature, the present invention is configured such that the motor is configured by a motor generator, and when the remaining power of the battery is equal to or lower than a lower limit value, the motor generator functions as a generator, and the compression ratio of the engine The third feature is that the engine is started while forcing the engine to the low compression ratio side, and the output of the engine is transmitted to the drive wheel and the motor / generator.

  Furthermore, in addition to the first feature, the present invention further includes a generator driven by the output of the engine, and when the remaining battery charge of the battery is equal to or lower than the lower limit value, the engine and the generator are connected to each other. A fourth feature is that the engine is started while forcing the compression ratio to the low compression ratio side, and the output of the engine is transmitted to the drive wheels and the generator.

  According to the first feature of the present invention, at the time of starting, the engine is first motored simultaneously with the starting by the output of the motor, and during this motoring, the compression ratio of the engine corresponds to the driving condition of the vehicle. After that, the engine ignition device is operated, so that the change of the compression ratio to the one corresponding to the operating condition is completed before starting the engine during the start by the motor output. There is no delay in changing the compression ratio, and good drivability can be obtained. Further, unnecessary changes in the compression ratio are avoided and the number of changes is reduced, which can contribute to improving the durability of the variable compression ratio apparatus.

  According to the second feature of the present invention, the change in the compression ratio of the engine can be made to accurately correspond to the operating conditions, and drivability can be improved.

  According to the third feature of the present invention, when the remaining amount of charge in the battery is equal to or lower than the lower limit value, the motor / generator functions as a generator and the engine compression ratio is forced to the low compression ratio side. Since the engine output is transmitted to the drive wheel and motor generator, the battery can be charged from the start of the engine, and knocking can be avoided even if the engine load increases accordingly. As a result, high load start can be performed smoothly.

  According to the fourth feature of the present invention, as in the case of the third feature, when the remaining amount of charge of the battery is lower than the lower limit value, the battery is charged from the start of the engine. In addition, the engine load can be increased and the high load can be started smoothly while avoiding knocking.

  Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  FIG. 1 is a longitudinal sectional front view of a main part of an engine for a hybrid vehicle equipped with a variable compression ratio device, and FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 3 shows a high compression ratio state, corresponding to FIG. 2, FIG. 4 is a sectional view taken along the line 4-4 in FIG. 2, FIG. 5 is an enlarged sectional view taken along the line 5-5 in FIG. Fig. 7 is a sectional view taken along line -6, Fig. 7 is a sectional view taken along line 7-7 in Fig. 3, Fig. 8 is an explanatory view of switching action from a high compression ratio state to a low compression ratio state, and Fig. 9 is a low compression ratio state to a high compression ratio state. FIG. 10 is a hybrid system diagram of the hybrid vehicle according to the first embodiment of the present invention, FIG. 11 is a compression ratio switching region map provided in an electronic control unit in the hybrid system, and FIG. FIG. 13 is a start time series chart, FIG. 14 is a hybrid system diagram of a hybrid vehicle according to the second embodiment of the present invention, and FIG. 15 is a flowchart showing the start program of the hybrid system. .

  First, the description starts with the description of the first embodiment of the present invention shown in FIGS.

  The first embodiment is applied to a parallel hybrid system of a vehicle. In this system, as shown in FIG. 10, an engine E and a motor generator MG are connected to each other via a clutch CL, and their common output shaft is driven via a transmission TM and a differential device DF. Connected to wheels W, W. A battery BT is connected to the motor generator MG via an inverter IV. Further, an electronic control unit 50 for controlling these operations is connected to the clutch CL, the motor / generator MG, and the transmission TM.

  Thus, in this parallel hybrid system, the power of the engine E is used as the main power to drive the driving wheels W and W, and the motor generator MG is driven as a generator to charge the battery. When starting or accelerating which requires a certain driving force, the motor / generator MG is operated as a motor, and its output is added to the power of the engine E.

  Next, the variable compression ratio device included in the engine E will be described with reference to FIGS.

  1 to 3, the internal combustion engine E has a crankshaft 9 supported by a crankcase 3 via bearings 8 and 8 ′, and the crankshaft 9 has an inside of a cylinder bore 2 a of the cylinder block 2. The piston 5 is connected to the piston 5 that moves up and down through the connecting rod 7. The piston 5 is slidably fitted to a piston inner 5a connected to the small end portion 7a of the connecting rod 7 via a piston pin 6 and the outer peripheral surface of the piston inner 5a. The piston outer 5b is movable between a predetermined low compression ratio position L (see FIG. 2) and a high compression ratio position H (see FIG. 3), and the piston outer 5b is mounted on the outer periphery thereof. A plurality of piston rings 10 a to 10 c are slidably fitted to the inner peripheral surface of the cylinder bore 2 a and the head portion 5 bh faces the combustion chamber 4 a of the cylinder head 4.

  A plurality of spline teeth 11a and spline grooves 11b that extend in the axial direction of the piston 5 and engage with each other are formed on the sliding fitting surfaces of the piston inner and outer 5a, 5b. The piston inner and outer 5a, 5b , The relative rotation around these axes is not possible. A stop ring 18 that restricts the relative movement of the piston inner 5a and the piston outer 5b in the axial direction is locked to the inner peripheral surface of the piston outer 5b opposite to the head portion 5bh across the piston inner 5a.

Between the piston inner 5a and the head portion 5BH, it is the first cam mechanism 15 ₁ is Kai裝to first control the axial spacing S ₁ between them, also between the piston inner 5a and retaining ring 18, A second cam mechanism 15 ₂ for controlling the second axial interval S ₂ therebetween is interposed. By increasing or decreasing the first and second axial distances S ₁ and S ₂ opposite to each other by the first and second cam mechanisms 15 ₁ and 15 ₂ , the piston outer 5b can move the piston pin with respect to the piston inner 5a. The low compression ratio position L close to and the high compression ratio position H close to the combustion chamber 4a are alternately held.

As shown in FIGS. 2, 3 and 6, the first cam mechanism 15 ₁ includes a first fixed cam 16 ₁ of the upper to be formed in the head portion 5bh inner wall of the piston outer 5b, integrally on the upper surface of the piston inner 5a consists projecting from the pivot portion 12 One fitted rotatablyゝfirst rotating cam plate lower part is supported on the upper surface of the piston inner 5a 17 ₁ Tokyo on.

First rotating cam plate 17 _1, the first and second rotational position A is set around its axis, as it is capable of rotating between B, and cooperates ₁ and the first fixed cam 16 by its reciprocating rotational, said first axial spacing S ₁ may increase or decrease. Specifically, the first fixed cam 16 ₁ is composed of a plurality of cam peaks 16 ₁ , 16 ₁ ... Arranged in the circumferential direction, and the first rotating cam plate 17 ₁ has a plurality of cam peaks also arranged in the circumferential direction. 17 ₁ , 17 ₁ ... Are integrally formed.

Thus, when the first rotary cam plate 17 ₁ is in the first rotational position A, the upper first fixed cam is located in the valley between the adjacent cam peaks 17 ₁ , 17 _{1 of} the first rotary cam plate 17 _1. 16 ₁ of the cam nose 16 ₁ are possible out (see (a), (b) in FIG. 8), as a result, transition to a low compression ratio position L or high compression ratio position H of the piston outer 5b is allowed The And if the upper and lower cam lobes 16 ₁ a, 17 ₁ a is Kamiae, the first cam mechanism 15 ₁ will reduce the axial contraction state is in the first axial spacing S _1.

Also when the first rotating cam plate 17 ₁ is in the second rotational position B, the first rotating cam plate 17 ₁ and the first fixed cam 16 ₁ cam lobes 16 ₁ a, 17 ₁ a to each other the flat top surface to abut (see FIG. 8 (a)) that is, the first cam mechanism 15 ₁ is a axial expanded state, the increased first axial spacing S _1, a high compression ratio position of the piston outer 5b Will be held at H.

The piston inner 5a, and the first between rotating cam plate 17 _1, a first actuator 20 ₁ is rotated alternately first rotating cam plate 17 ₁ to the first rotational position A and the second rotational position B is provided.

First actuator 20 ₁ is configured as shown in FIGS. 2 and 4. That is, the piston inner 5a, a piston pin 6 interposed therebetween a pair of bottom extending parallel therewith the cylinder bore 21 _1, 21 _1, the long hole 29 ₁ extending through the upper wall of the intermediate portion of each cylinder bore 21 ₁ 29 ₁ and a pair of pressure receiving pins 28 ₁ , 28 _{1 that} are integrally projected on the lower surface of the first rotating cam plate 17 ₁ and are arranged on the diameter line thereof through the long holes 29 ₁ , 29 ₁ . It faces the cylinder holes 21 ₁ and 21 ₁ . The long holes 29 ₁ and 29 ₁ do not prevent the pressure receiving pins 28 ₁ and 28 ₁ from moving between the first rotation position A and the second rotation position B together with the first rotation cam plate 17 ₁ .

An operating plunger 23 ₁ and a bottomed cylindrical return plunger 24 ₁ are slidably fitted in each cylinder hole 21 ₁ with a corresponding pressure receiving pin 28 ₁ interposed therebetween. At this time, the operating plungers 23 ₁ , 23 ₁ and the return plungers 24 ₁ , 24 ₁ are arranged symmetrically with respect to the axis of the piston 5.

In each cylinder hole 21 ₁ , a first hydraulic chamber 25 ₁ is formed in which the inner end of the actuating plunger 23 ₁ faces. When hydraulic pressure is supplied to the chamber 25 ₁ , the actuating plunger 23 ₁ receives pressure and receives the pressure. The first rotary cam plate 17 ₁ is rotated to the second rotational position B via the pin 28 ₁ .

Also the open end of each cylinder bore 21 _1, cylindrical spring retaining tube 35 ₁ is engaged through the retaining ring 36 _1, between the plunger 24 ₁ returning said this spring holding cylinder 35 ₁ spring 27 _first return to the back biasing the plunger 24 ₁ on the pressure receiving pin 28 ₁ side is provided in a compressed state.

And Thus, a first rotation position A of the first rotating cam plate 17 ₁ is defined by the tip pressure pin 28 ₁ of the actuating plunger 23 ₁ abutting the bottom surface of each cylinder bore 21 ₁ is in contact, the first second rotational position B of the rotation cam plate 17 ₁ is defined by abutting the tip of the plunger 24 ₁ spring holding cylinder 35 ₁ back pressed to the pressure receiving pin 28 _1.

Also as shown in FIGS. 2, 3 and 6, the second cam mechanism 15 ₂ includes a second fixed cam 16 _{and second} upper portion formed on the lower end wall of the piston inner 5a, the piston outer on the stop ring 18 5b has a second rotating cam plate 17 ₂ which the lower portion rotatably fitted to the inner peripheral surface of the inner periphery of the piston outer 5b, abutting annular upper surface of the second rotating cam plate 17 ₂ and the shoulder portion 19 is formed, the shoulder portion 19 and the stop ring 18 and the second rotating cam plate 17 ₂ is rotatably clamped, the axial movement is prevented with respect to the piston outer 5b.

The second rotating cam plate 17 _2, as it can rotate between the third rotation position C and the fourth rotational position D is set around its axis, in cooperation with the ₂ second fixed cam 16 by its reciprocating rotational , The second axial distance S ₂ is increased or decreased. Specifically, the second fixed cam 16 ₂ is composed of a plurality of cam peaks 16 ₂ a, 16 ₂ a,... Arranged in the circumferential direction, and the second rotating cam plate 17 ₂ has a plurality of the same in the circumferential direction. Cam ridges 17 ₂ a, 17 ₂ a... Are integrally formed.

The rotation angle between the third and fourth rotation positions C and D of the second rotation cam plate 17 ₂ is the same as the rotation angle between the first and second rotation positions A and B of the first rotation cam plate 17 ₁ . Is set. The least effective height of the second fixed cam 16 ₂ and the second rotating cam plate 17 _{and second} cam lobes 16 ₂ a, 17 ₂ a, the first fixed cam 16 ₁ and the first rotating cam plate 17 _first cam nose It is set to be the same as that of 16 ₁ a and 17 ₂ a.

Thus, when the second rotary cam plate 17 ₂ is at the third rotational position C, the cam peaks 16 ₂ a and 17 ₂ a of the second rotary cam plate 17 ₂ and the second fixed cam 16 ₂ are flat. thereby abutting the top surface (see FIG. 8 (d)) that is, the second cam mechanism 15 ₂ is a axial expanded state, increasing the second axial spacing S _2, the piston outer 5b low Hold at compression ratio position L.

The ₂ second rotating cam plate 17 when in the fourth rotational position D, and the valleys between the cam lobes 17 ₂ a, 17 ₂ a adjacent the second rotating cam plate 17 of the _second fixed cam 16 ₂ The cam crest 16 ₂ a can enter and exit (see (a) and (c) of FIG. 8), and as a result, the piston outer 5b is allowed to shift to the low compression ratio position L or the high compression ratio position H. When the upper and lower cam peaks 16 ₂ a and 17 ₂ a are engaged with each other, the second cam mechanism 15 ₂ is in the axially contracted state, and the second axial interval S ₂ is reduced.

Between the piston inner 5a and the second rotating cam plate 17 _2, the second actuator 20 ₂ for rotating alternately the second rotating cam plate 17 ₂ to the third rotation position C and the fourth rotational position D is provided.

Second actuator 20 ₂ has a structure as shown in FIGS. 2 and 6. That is, the piston inner 5a, the piston pin 6 interposed therebetween pair of bottomed cylinder bore extending parallel therewith 21 _2, 21 ₂ and a long hole 29 ₂ extending through the upper wall of the intermediate portion of each cylinder bore 21 ₂ , 29 ₂ and is provided, on the lower surface of the second rotating cam plate 17 ₂ is integrally projected a pair of pressure receiving pins 28 arranged on a diameter line _2, 28 ₂ through the slots 29 _2, 29 ₂ It faces the cylinder holes 21 ₂ and 21 ₂ . Each long hole 29 ₂ does not prevent the pressure receiving pin 28 ₂ from moving between the third rotation position C and the fourth rotation position D together with the second rotation cam plate 17 ₂ .

An operating plunger 23 ₂ and a bottomed cylindrical return plunger 24 ₂ are slidably fitted in each cylinder hole 21 ₂ with a corresponding pressure receiving pin 28 ₂ interposed therebetween. At this time, the operating plungers 23 ₂ , 23 ₂ and the return plungers 24 ₂ , 24 ₂ are arranged symmetrically with respect to the axis of the piston 5.

In each cylinder hole 21 ₂ , a second hydraulic chamber 25 ₂ is formed in which the inner end of the actuating plunger 23 ₂ faces. When hydraulic pressure is supplied to the chamber 25 ₂ , the actuating plunger 23 ₂ receives the hydraulic pressure and receives the pressure. The second rotary cam plate 17 ₂ is rotated to the fourth rotational position D via the pin 28 ₂ .

A cylindrical spring holding cylinder 35 ₂ is locked to the open end of each cylinder hole 21 ₂ via a retaining ring 36 ₂ , and between the spring holding cylinder 35 ₂ and the return plunger 24 _2. spring 27 ₂ return to its back biases the plunger 24 ₂ to the pressure receiving pin 28 ₂ side is provided in a compressed state. Thus, the second actuator 20 ₂ is configured symmetrically with the first actuator 20 ₁ .

Thus, the third rotational position C of the second rotary cam plate 17 ₂ is such that the pressure receiving pins 28 ₂ , 28 ₂ are provided at the tips of the operating plungers 23 ₂ , 23 _{2 that} are in contact with the bottom surfaces of the cylinder holes 21 ₂ , 21 _2. The fourth rotation position D of the second rotating cam plate 17 ₂ is defined by the return plunger 24 ₂ pushed by the pressure receiving pin 28 ₂ contacting the tip of the spring holding cylinder 35 _2. .

In the above, the first rotating cam plate 17 ₁ and the first actuator 20 ₁ , and the second rotating cam plate 17 ₂ and the first actuator 20 ₂ are different from each other in the inertia force difference between the piston inner 5a and the piston outer 5b, and the piston outer 5b. Friction force received from the inner surface of the cylinder bore 2a, negative pressure received by the piston outer 5b from the combustion chamber 4a side, positive pressure, etc., and external forces acting to move the piston inner 5a and outer 5b apart from each other in the axial direction, The piston outer 5b is allowed to move between the low compression ratio position L and the high compression ratio position H.

1 and 2 again, a cylindrical oil chamber 41 is defined between the piston pin 6 and the sleeve 40 press-fitted into the hollow portion thereof. The oil chamber 41 is defined as the first and second actuators 20. _First and second distribution oil passages 42 ₁ and 42 ₂ connected to both hydraulic chambers 25 ₁ and 25 ₂ of ₁ and 20 ₂ are provided across the piston pin 6 and the piston inner 5a. The oil chamber 41 is connected to an oil passage 44 provided across the piston pin 6, the connecting rod 7 and the crankshaft 9. The oil passage 44 is connected to an oil pump 46 serving as a hydraulic pressure source via an electromagnetic switching valve 45 and an oil sump. 47 is switchably connected. The oil pump 46 is mechanically driven from the crankshaft 9.
[Switching from high compression ratio position to low compression ratio position]
Now, it is assumed that the piston outer 5b is held at the high compression ratio position H as shown in FIG. Therefore, in the first cam mechanism 15 ₁ , the upper and lower cam peaks 16 ₁ a and 17 ₁ a are in the axially expanded state with the top surfaces facing each other, and in the second cam mechanism 15 ₂ , the upper and lower cam peaks 16 ₂ a, 17 ₂ a are in an axially contracted state in which the _two a mesh with each other.

In this state, when the electromagnetic switching valve 45 is in a non-energized state, that is, in an off state as shown in FIG. 1, and the oil passage 44 is opened to the oil sump 47, the hydraulic pressures of the first and second actuators 20 ₁ and 20 ₂ chamber 25 _1, 25 _2, since both are open to the oil reservoir 47 through the oil chamber 41 and the oil passage 44, first the actuator 20 _1, returns the plunger 24 ₁ back pressure pin 28 by the biasing force of the spring 27 _{1 1} is pressed, and the first rotating cam plate 17 ₁ attempts to rotate in the first rotational position a, the second actuator 20 _1, the pressure receiving pin 28 ₂ by the biasing force of the plunger 24 ₂ return spring 27 ₂ return pressing and, to rotate the second rotating cam plate 17 ₂ to the third rotational position C.

Therefore, the piston 5 moves to the intake stroke, the piston inner 5a, since the downward inertial force prior to the piston outer 5b acts, the first cam mechanism 15 _1, between the piston inner 5a and the piston outer 5b Freed from thrust loads. Therefore, first, the first rotating cam plate 17 ₁ is quickly rotated into the first rotational position A via the pressure pin 28 ₁ by the urging force of the spring 27 _first return of the first actuator 20 _1. As a result, as shown in FIG. 8 (b), the first cam mechanism 15 ₁ of the upper and lower cam lobes 16 ₁ a, 17 ₁ a is allowed arrangement meshing is shifted by a half pitch from each other.

Next, when the piston 5 comes in the latter half of the compression stroke, an upward inertial force acts on the piston inner 5a prior to the piston outer 5b, so that the piston outer 5b is as shown in FIG. while meshing the first cam mechanism 15 ₁ of the upper and lower cam lobes 16 ₁ a, 17 ₁ a to each other, i.e., while the first cam mechanism 15 ₁ is contracted in the axial direction, and lowered relative piston inner 5a, It occupies the low compression ratio position L.

With such a piston outer 5b is lowered relative piston inner 5a, will be in the second cam mechanism 15 _2, the second rotating cam plate 17 ₂ to the second fixed cam 16 ₂ descends, and since accompanied no upper and lower cam lobes 16 ₂ a, 17 ₂ a is released from the engagement state, the second rotating cam plate 17 ₂ to the pressure receiving pin 28 ₂ by the urging force of the spring 27 ₂ return of the second actuator 20 ₂ Through the third rotation position C. As a result, as shown in FIG. 8D, the upper and lower cam ridges 16 ₂ a and 17 ₂ a of the second cam mechanism 15 ₂ abut the flat top surfaces against each other. By such an axial expansion action of the second cam mechanism 15 ₂ , the second axial interval S ₂ is increased and the low compression ratio position L of the piston outer 5b is maintained, and the internal combustion engine E is subjected to low compression. It becomes a specific state.
[Switching from low compression ratio position to high compression ratio position]
Next, when the internal combustion engine E is operated at a high speed, the electromagnetic switching valve 45 is energized, that is, turned on, and the oil passage 44 is connected to the oil pump 46. As a result, the discharge hydraulic pressure of the oil pump 46 is changed to the oil passage 44 and oil chamber 41. since applied to full hydraulic chamber 25 _1, 25 ₂ through, the first actuator 20 _1, the first rotating cam plate via the pressure pin 28 ₁ actuating plunger 23 ₁ receives the first oil pressure chamber 25 ₁ of the hydraulic 17 ₁ attempts to rotate toward the second rotational B, the second actuator 20 _2, actuating plunger 23 ₂ via the pressure receiving pin 28 ₂ receives the second hydraulic chamber 25 _{and second} hydraulic second rotating cam plate 17 ₂ is to be rotated toward the fourth rotational position D.

Therefore, the piston 5 moves to the exhaust stroke, for receiving the upward inertial force piston inner 5a is in advance of the piston outer 5b, the second cam mechanism 15 ₂ is interposed between the piston inner 5a and retaining ring 18 Freed from thrust loads. Therefore, first, the second rotating cam plate 17 ₂ is quickly rotated to the fourth rotational position D via the pressure receiving pin 28 ₂ by the pressing force of the hydraulic plunger 23 ₂ of the second actuator 20 ₂ . As a result, as shown in FIG. 9B, the upper and lower cam peaks 16 ₂ a and 17 ₂ a of the second cam mechanism 15 ₂ are arranged so as to be able to engage with each other with a half-pitch shift.

Next, when the piston 5 comes in the latter half of the intake stroke, a downward inertial force acts on the piston inner 5a in advance of the piston outer 5b, so that the piston outer 5b is as shown in FIG. while meshing the second cam mechanism 15 and _second upper and lower cam lobes 16 ₂ a, 17 ₂ a from each other, i.e., while the second cam mechanism 15 ₁ is contracted in the axial direction, relative to rise relative to the piston inner 5a, The high compression ratio position H will be occupied.

With such a piston outer 5b is relatively raised with respect to the piston inner 5a, will be the first cam mechanism 15 _1, the second fixed cam 16 ₁ with respect to the first rotating cam plate 17 ₁ rises, and since accompanied no upper and lower cam lobes 16 ₁ a, 17 ₁ a is released from the engagement state, the first rotating cam plate 17 ₁ is receiving pin 28 by the pressing force of the first actuator 20 ₁ of the working plunger 23 _first hydraulic ₂ to quickly rotate to the second rotational position B (see FIG. 5). As a result, as shown in (d) of FIG. 9, the first cam lobes of the upper and lower cam mechanism _{15 1 16 1 a, 17 2} a is brought into contact opposite to each other flat top surface. The axial expansion effect of such a first cam mechanism 15 _1, a first axial spacing S ₁ is increased, it will retain a high compression ratio position H of the piston outer 5b. Thus, the internal combustion engine E is in a high compression ratio state. The configuration of the variable compression ratio device follows that disclosed in Patent Document 2.

  As shown in FIG. 1, the electronic control unit 50 is connected to the electromagnetic switching valve 45 in order to control its operation. The electronic control unit 50 includes a rotational speed sensor 51n for detecting the engine rotational speed, a throttle sensor 51θ for detecting the throttle valve opening of the engine E, a clutch sensor 51c for detecting the ON state of the clutch CL, and an electromagnetic switching valve 45. Output signals of a high compression ratio sensor 51h that detects an ON state (high compression ratio state), a battery sensor 51b that detects that the remaining amount of electricity stored in the battery BT is equal to or less than a predetermined lower limit, and a vehicle speed sensor 51v that detects the vehicle speed. Is entered. The electronic control unit 50 is provided with a compression ratio switching area map M1 (FIG. 11).

  Next, the execution procedure of the start program of the electronic control unit 50 will be described with reference to the flowchart of FIG. 12 and the start time series chart of the hybrid system of FIG.

First, the system is started in step S1 in FIG. 12, and the transmission TM is set in the D range in step S2, and the system is set in a standby state (see T _{0 to} T _{1 in} FIG. 13). In step S3, it is determined whether or not the system is in a standby state. If YES, the process proceeds to step S4 to determine whether or not the engine E is in an ignition state. If NO, the process proceeds to step S5. In step S6, it is determined whether or not the clutch CL is in an ON state. If NO, the process proceeds to step S6. If NO, the clutch CL is turned on in step S6 and the process returns to step S5.

If the determination result in step S5 is YES, the process proceeds to step S7 to determine whether or not the remaining charge amount of the battery BT is equal to or greater than the lower limit value. If YES, the throttle is determined based on the output signal of the throttle sensor 51θ in step S8. detects the opening, then after the vehicle is started by operating the motor-generator MG as a motor in a step S9, it performs motoring of the engine E in step S10 (see T ₁ through T ₃ in FIG. 13).

  Next, in step S11, the current compression ratio state is detected based on the output signal of the high compression ratio sensor 51h. In step S12, the required driving force of the driver is calculated from the output signals of the engine speed sensor 51n and the throttle sensor 51θ. In step S13, the target compression ratio of the engine E is determined from the required driving force and the compression ratio switching area map M1, and the process proceeds to step S14.

  In step S14, it is determined whether or not the current compression ratio is equal to the target compression ratio. If YES, the engine E is operated normally by setting the ignition device of the engine E to the operating state in step S15. Let

If the determination result in step S14 is NO, the process proceeds to step S16 to determine whether or not the target compression ratio is smaller than the current compression ratio. If YES, the electromagnetic switching valve 45 is turned off in step S17. the engine E to the high compression ratio state in the state, if NO, the to the electromagnetic switching valve 45 to the oN state at step S18 that the engine E to the low compression ratio state (see T ₂ of the FIG. 13).

Thus, when starting with the motor / generator MG, the engine E is motored at the same time as starting, and the appropriate compression ratio of the engine E is determined from the required driving force of the driver indicated by the vehicle speed and the throttle valve opening. By applying the appropriate compression ratio to the engine E during motoring, the engine E can be operated at the appropriate compression ratio. After that, according to the operation of the ignition device, the engine E The operation is performed with an appropriate compression ratio, and the operation delay of the compression ratio variable device can be eliminated. Thus, with good drivability, it is possible to perform traveling by summing the output of the motor and the engine (see T ₃ and subsequent FIG. 13). Further, unnecessary changes in the compression ratio are avoided and the number of changes is reduced, which can contribute to improving the durability of the variable compression ratio apparatus.

  If the determination result in step S7 is NO, the process proceeds to step S19 to switch the motor / generator MG to the generator function to prepare for charging the battery BT, and then forcibly turns off the electromagnetic switching valve 45 in step S20. The engine E is forced into a low compression ratio state and the engine E is started in step S21, and then the process proceeds to step S14.

  As described above, when the remaining amount of electricity stored in the battery BT becomes equal to or less than the predetermined lower limit value, the battery BT is prepared for charging and the electromagnetic switching valve 45 is turned off to reduce the compression to the engine E during motoring. Since the engine E is started after the ratio is forcibly applied, the battery BT can be charged from the start of the engine E, and knocking is also avoided due to the increase in the engine load associated therewith. , High load start can be performed smoothly. In this case, the motoring of the engine E is not performed because the charging of the battery BT is prioritized. Therefore, the change to the low compression ratio by turning off the electromagnetic switching valve 45 is performed during the operation of the engine E. It is unavoidable that the changes will be made and the changes will be delayed.

  Next, a second embodiment of the present invention shown in FIGS. 14 and 15 will be described.

  The second embodiment is different from the previous embodiment only in that the vehicle employs a parallel series hybrid system, and the compression ratio varying device provided in the engine E is not different from the previous embodiment. Therefore, only the parallel series hybrid system will be described.

  The engine E is connected to the power distribution device DV via the transmission TM. This power distribution device DV distributes the power of the engine E in two and outputs it to the first and second output shafts d1 and d2. The first output shaft d1 and the output shaft of the motor M are directly connected to each other. At the same time, it is connected to drive wheels W, W via a differential device DF. The second output shaft d2 of the power distribution device DV is connected to the generator G, and the generator G is connected to the battery BT via the inverter IV. The battery BT is connected to the motor M through the inverter IV. The power distribution ratio to the first and second output shafts d1 and d2 in the power distribution device DV is controlled by the electronic control unit 50 according to the driving conditions of the vehicle. The engine E in this system is also provided with the variable compression ratio device shown in FIGS.

  The execution procedure of the start program of the electronic control unit 50 in the second embodiment is shown in the flowchart of FIG.

  In this flowchart, the difference from the flowchart of the previous embodiment (FIG. 12) will be described. In step S5, it is determined whether or not the power distribution ratio to the first output shaft d1 by the power distribution device DV is 100%. , N, in step S6, the power distribution ratio to the first output shaft d1 is set to 100%. That is, the engine E and the motor M are directly connected to each other.

  Therefore, thereafter, after the same process as in the previous embodiment, the start by the output of the motor M and the motoring of the engine E are performed, and the compression ratio of the engine E can be appropriately controlled during the motoring.

  In step S19, the generator G can be operated to prepare for charging the battery BT. Thereafter, the transition is the same as in the previous embodiment.

The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention. For example, when the first and second actuators 20 ₁ and 20 ₂ are supplied with hydraulic pressure from the oil pump 46, the variable compression ratio device is configured to drive the piston inner 5a from the high compression ratio position to the low compression ratio position. You can also Moreover, it can replace with the variable compression ratio apparatus of the said Example, and can also employ | adopt the variable compression ratio apparatus of patent documents 3-5.

The principal part longitudinal section front view of the engine for hybrid vehicles provided with a compression ratio variable apparatus. A low compression ratio state is shown in the enlarged sectional view taken along line 2-2 in FIG. FIG. 3 is a diagram corresponding to FIG. 4-4 sectional drawing of FIG. FIG. 5 is an enlarged sectional view taken along line 5-5 in FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 3. Switching operation explanatory diagram from a high compression ratio state to a low compression ratio state. FIG. 4 is a switching operation diagram from a low compression ratio state to a high compression ratio state. 1 is a hybrid system diagram of a hybrid vehicle according to a first embodiment of the present invention. The compression ratio switching area map provided in the electronic control unit in the hybrid system. The flowchart which shows the start program of the hybrid system. Start time series chart. The hybrid system figure of the hybrid vehicle which concerns on 2nd Example of this invention. The flowchart which shows the start program of the hybrid system.

Explanation of symbols

BT ... Battery E ... Engine G ... Generator MG ... Motor Generator M ... Motor W ... Drive Wheel

Claims (4)

A power source comprising a combination of an engine (E) and a motor (MG, M) operated by electric power of a battery (BT) is provided, and the engine (E) has a variable compression ratio that can change the compression ratio. In a hybrid vehicle provided with a device,
When starting, the drive wheels (W) are driven by the output of the motors (MG, M) and the engine (E) is motored. During this motoring, the compression ratio of the engine (E) is used as the vehicle operating condition. A hybrid system for a hybrid vehicle, wherein the ignition system of the engine (E) is operated after that. The hybrid system for a hybrid vehicle according to claim 1,
The hybrid system for a hybrid vehicle, wherein the operating conditions of the vehicle include a throttle valve opening and a vehicle speed of the engine (E). The hybrid system for a hybrid vehicle according to claim 1,
When the motor is composed of a motor / generator (MG) and the remaining power of the battery (BT) is less than the lower limit, the motor / generator (MG) functions as a generator and the compression ratio of the engine (E) is increased. A hybrid system for a hybrid vehicle, wherein the engine (E) is started while being forced to a low compression ratio side, and the output of the engine (E) is transmitted to a drive wheel (W) and a motor generator (MG) . The hybrid system for a hybrid vehicle according to claim 1,
When the generator (G) is driven by the output of the engine (E) and the remaining power of the battery (BT) is below the lower limit, the engine (E) and the generator (G) are connected, The engine (E) is started while forcing the compression ratio of the engine (E) to the low compression ratio side, and the output of the engine (E) is transmitted to the drive wheel (W) and the generator (G). A hybrid system for hybrid vehicles.

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