JP2008115830A - Control device and control method of reciprocation type internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve engine-starting performance and warming-up performance without loss of combustion stability by optimizing piston motion at startup of the engine and idling time. <P>SOLUTION: An actuator 27 changes and retains the position of a link-supporting part 26 of a control link 25 which is connected to one of the links 23, 24 connecting a piston 12 to a crank pin 22. The piston motion can be changed in accordance with the state of the operation of the engine by controlling the operation of the actuator 27 by a control part 40. A target compression ratio which heavily depends on the position of the compression top dead center and a target air-intake stroke amount which is the equivalent of the length of the intake stroke are calculated in accordance with the state of the operation of the engine. Then the target position of the link-supporting part is set based on the target compression ratio and the target air-intake stroke amount. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to control of a reciprocating internal combustion engine that can change the piston motion of a piston that reciprocates in a cylinder using a multi-link piston-crank mechanism.

Patent Document 1 discloses an example of a multi-link type piston-crank mechanism of a reciprocating internal combustion engine that can change the engine compression ratio with changes in piston motion. In this mechanism, the piston that reciprocates in the cylinder and the crank pin of the crankshaft are linked by a plurality of links, and the position of the link support portion of the control link connected to one of the plurality of links is changed and held by an actuator. By doing so, it is possible to change the engine compression ratio in accordance with the change of the piston operation with respect to the crank angle, that is, the piston motion. The engine compression ratio is generally set according to the engine load and the engine speed, as described in Patent Documents 1 and 2 above.
JP 2003-201875 A JP 2005-140108 A

  In a four-cycle reciprocating internal combustion engine that can change the piston motion using such a multi-link piston-crank mechanism, the engine compression ratio that greatly depends on the position of the compression top dead center and the intake air amount are greatly affected. The length of the intake stroke to be exerted, that is, the intake stroke amount can be changed independently of each other. However, specific settings of the engine compression ratio and the intake stroke amount, particularly the settings at the time of engine start and idling that require engine startability and combustion stability, have been sufficiently considered so far. It has not been done and there is room for improvement.

  The present invention has been made in view of such problems, and relates to control of a four-cycle reciprocating internal combustion engine, in which a control link is connected to one of a plurality of links that link a piston and a crankpin of a crankshaft. Further, the piston motion can be changed by controlling the operation of an actuator that changes and holds the position of the link support portion of the control link. Then, according to the engine operating state, target value calculation means for calculating a target compression ratio depending on the position of the compression top dead center and a target intake stroke amount corresponding to the length of the intake stroke, and the target compression ratio And a target position setting means for setting a target position of the link support portion based on the target intake stroke amount.

  According to the present invention, it is possible to appropriately set the engine compression ratio and the intake stroke amount according to the engine operating state by using a multi-link type piston-crank mechanism. Improvement of warm-up during idling, and improvement of combustion stability can be achieved.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIGS. 1 and 2, this internal combustion engine (engine) is a four-cycle spark-ignition type four-cylinder reciprocating internal combustion engine in which four strokes of expansion, exhaust, intake, and compression are defined as one cycle. A crankshaft 11 as an engine output shaft is rotatably supported on the cylinder block 10, and a plurality of pistons 12 are fitted in such a manner that they can reciprocate, in this example, four # 1 to # 4 cylinders (cylinders). 13 is formed. The cylinder head 14 fixed to the upper portion of the cylinder block 10 is formed with a pent roof type combustion chamber 15 between the crown surface of the piston 12 and an intake valve 17 for opening and closing an intake passage (intake port) 16. And an exhaust valve 19 for opening and closing an exhaust passage (exhaust port) 18 and an ignition plug 20 for spark-igniting the air-fuel mixture in the combustion chamber 15 are provided.

  The intake passage 16 is provided with an electrically controlled throttle valve 41 whose opening degree can be adjusted and controlled according to a control signal from the control unit 40, and an intake air amount (intake) upstream of the throttle valve 41. An air flow meter 42 for detecting an air amount) is provided, and an injector (fuel injection valve) 43 for injecting fuel into the intake port is provided. As sensors for detecting the engine operating state, an accelerator opening sensor 44 for detecting an accelerator operation amount (accelerator opening) by a driver, a crank angle sensor 45 for detecting a rotation angle of the crankshaft 11, that is, a crank angle (CA), A cam angle sensor 47 for detecting the rotation angle of the cam shaft, a water temperature sensor 46 for detecting the coolant temperature as the engine temperature, a vehicle speed sensor 50 for detecting the vehicle speed, the air flow meter 42, and the like are provided. Cylinder discrimination and engine speed detection are performed by a combination of 45 and the detection signal of the cam angle sensor 47.

  The control unit 40 is a digital computer system having a function of storing and executing various control processes. In addition to the detection signals from the sensors, the control unit 40 is a throttle valve based on an engine start signal from a starter switch (SW) 48 and the like. 41, an injector 43, a spark plug 20, a starter 49 that rotationally drives or cranks the crankshaft 11 when the engine is started, and a plurality of multi-link piston-crank mechanisms 21 provided for each cylinder as described later (this embodiment) In the example, a control signal is output to four actuators 27 and the like to control the operation. The battery 52 stores electric power generated by an alternator and a motor generator (not shown). The starter 49 and auxiliary equipment such as an air conditioner / compressor (not shown) are driven by electric power (voltage / current) supplied from the battery 52. The storage state of the battery 52, that is, the voltage that can be supplied, is detected and monitored by a battery controller (battery state detection means) 53.

  As shown in FIG. 2, the multi-link type piston-crank mechanism 21 links each piston 12 and the crank pin 22 of the crankshaft 11 by a plurality of links 23 and 24, and one of the plurality of links 23 and 24. The piston motion (PM) of the piston 12 can be changed by changing the position of the link support portion 26 of the control link 25 connected to the actuator 27 by the actuator 27. More specifically, the multi-link type piston-crank mechanism 21 includes a lower link 23 that is rotatably attached to the crankpin 22, an upper link 24 that connects the lower link 23 and the piston 12, and one end that is a lower link. The control link 25 is rotatably connected to the control link 25, and the link support portion 26 is provided at the other end of the control link 25. The piston 12 and the upper end of the upper link 24 are connected by a piston pin 28, the lower end of the upper link 24 and the lower link 23 are connected by a first connecting pin 29, and one end of the lower link 23 and the control link 25. Are connected by a second connecting pin 30. The lower link 23 mechanically includes a first arm 31 that connects the first connecting pin 29 and the second connecting pin 30, a second arm 32 that connects the first connecting pin 29 and the crank pin 22, and a second connection. And a third arm 33 connecting the pin 30 and the crank pin 22. The actuator 27 is provided for each cylinder 13 in this example.

  The actuator 27 may be a linear actuator using a linear motor (linear induction motor) that is electrically controlled. The linear actuator 27 is, for example, a guide rail 34 as a linear stator fixed to the inner surface of the cylinder block 10, and supported by the guide rail 34 so as to be capable of reciprocating linear movement. An armature and a magnetic field are respectively provided in the link support portion 26 as a mover that travels along the linear direction L1 parallel to the direction, and a cable 35 for supplying an induced current or the like to the link support portion 26. Is connected. Such a linear actuator 27 makes it possible to change the piston motion quickly and accurately according to the operating conditions and the number of revolutions, and the link support 26 can be accurately operated even during high-speed rotation of the engine. High speed and high accuracy can be realized, and friction of the link support portion 26 can be reduced. Note that a position sensor 51 for detecting the position of the link support portion 26 is preferably provided in order to accurately control the link support portion 26 for each cylinder by known feedback control or the like according to the crank angle.

  However, instead of such a linear actuator 27, a hydraulic actuator including an electromagnetic valve that controls hydraulic pressure and a hydraulic piston that operates by hydraulic pressure may be applied. By using a hydraulic actuator that controls the hydraulic pressure with such a solenoid valve and moves the link support portion directly with a hydraulic piston, the cost can be reduced and the operation with a large torque can be performed stably. It becomes possible.

  Moreover, it is good also as a structure using a magnetorheological fluid as an actuator. That is, the magnetorheological fluid is connected so as to suppress the speed of the link support portion 26 in the operation direction, and the motion of the link support portion 26 is changed by the force applied to the link support portion 26. The piston motion can be switched by changing the viscosity of the current flowing through the electromagnet according to the operating conditions. In this case, the mechanism is simple and the cost can be reduced.

  FIG. 3 shows a setting example of the link support portion 26 with respect to the crank angle, and FIG. 4 shows the position / operation of the piston 12 with respect to the crank angle, that is, the piston motion. In the figure, H1 indicates the first setting used in the medium to high load range, H2 indicates the second setting used in the low to medium load range, and H3 indicates the third setting. In these first to third settings, the intake stroke amounts IS1 and IS2, which are the length of the intake stroke, and the position of the compression top dead center, without changing the position of the exhaust top dead center and the position of the expansion bottom dead center, Each is changed. Such settings H1 to H3 can be realized by quickly changing the position of the link support portion 26 in accordance with the crank angle.

  In the first setting H1 used in the medium to high load range, the piston motion is made to have a characteristic close to a single vibration having excellent sound vibration performance, that is, a sine wave, by holding the link support portion 26 at a predetermined position. The position of the piston motion is generally increased as the link support portion 26 is lowered in the cylinder axial direction, and the position of the piston motion is generally decreased as it is raised toward the upper limit position ( FIG. 15).

  In the second setting H2 used in the low to medium load range, the link support portion 26 is reciprocated downward in the cylinder only during a predetermined operation period from the intake stroke to the expansion stroke in each cycle. Thus, in particular, the stroke amount of the intake stroke of the piston, that is, the intake stroke IS2, is made sufficiently smaller than the intake stroke IS1 in the first setting H1. Further, the position of the compression top dead center is increased and the engine compression ratio is increased as compared with the first setting. Accordingly, the expansion stroke can be lengthened while shortening the compression stroke, and the thermal efficiency can be increased.

  In the third setting H3, the exhaust top dead center and the intake bottom dead center are set to be the same as the second setting H2, and the intake stroke amount is made the same, while the compression top dead center is changed from the second setting H2. Is further increased to increase the engine compression ratio. That is, the first setting H1 is a setting of a large intake stroke amount / low compression ratio, the second setting H2 is a setting of a small intake stroke amount / medium compression ratio, and the third setting H3 is a small intake stroke amount.・ High compression ratio setting.

  FIG. 5 is a block diagram schematically showing target position setting processing of the link support unit 26 that is stored and executed by the control unit 40. The start / idle target value calculation unit (target value setting means) B1 starts the target throttle opening (tTVO), the target intake stroke amount (tSt), and the target compression ratio (tε) at the start and at the idle time. Based on the state and the warm-up state, for example, calculation and setting are performed with reference to a preset control map. Here, the “starting state” corresponds to the degree of ease of starting the engine by the starter 49, and is determined using, for example, the battery voltage, the engine speed during cranking, or the like. As shown in FIG. 6, the larger the intake stroke amount, the larger the intake negative pressure and the more fuel atomization is promoted. On the other hand, the friction loss is increased and the throttle opening is set to obtain an equivalent intake air amount. If the pressure is reduced, the suction negative pressure increases, and the pumping loss increases. Further, the higher the engine compression ratio, the higher the thermal efficiency. On the other hand, the motoring torque required during cranking by the starter 49 increases, and the warm-up performance indicated by the one-dot chain line in the figure decreases.

  Therefore, when the engine is started, the target compression ratio and the target intake stroke amount are calculated and set according to the state of the battery 52. Basically, the lower the starting state, that is, the lower the degree of difficulty in starting the engine and the higher the degree of difficulty, the lower the target compression ratio and the smaller the target intake stroke amount (see FIG. 7). Since the torque required for cranking can be reduced and the cranking speed can be increased, it is possible to effectively reduce and avoid an increase in starting time even in a situation where engine starting is difficult. Further, in order to ensure a desired intake air amount, the target throttle opening is calculated and set according to the target intake stroke amount so that the target throttle opening becomes smaller as the target intake stroke becomes larger.

  More specifically, at the time of cold start where the engine water temperature is low and warm-up operation is required, the target intake air is mainly set according to the battery voltage (startability) as shown in FIG. The stroke amount (simply abbreviated as “intake S amount” in the figure) is increased or decreased. That is, in the situation where the battery voltage (startability) is low, the startability is considered as the second setting H2 of the small intake stroke amount / medium compression ratio, and in the situation where the battery voltage is high, the combustion stability and the warm-up are set. Focusing on performance, the first setting H1 of the large intake stroke amount / low compression ratio is set. Further, in the case of engine start after warm-up when the engine water temperature is high and it is not necessary to perform warm-up operation, the target is mainly set according to the battery voltage (startability) as shown in the characteristics of the solid line in FIG. 7 and FIG. Increase or decrease the compression ratio. That is, in the situation where the battery voltage (startability) is low, the startability is emphasized, and the second setting H2 of the small intake stroke amount / medium compression ratio is set. In the situation where the battery voltage is high, the thermal efficiency is emphasized, The third setting H3 of the small intake stroke amount / high compression ratio is set.

  As shown in FIGS. 9 and 10, in the idle state, particularly in the idle state immediately after the engine is started, the target intake stroke and the target compression ratio are calculated according to the engine water temperature (engine temperature) related to the warm-up state. Specifically, in the case of warm-up idling (high idling) when the engine water temperature is low, emphasizing combustion stability and warm-up performance, increasing the target intake stroke, lowering the target compression ratio, In order to secure the intake air amount, the throttle opening is reduced as the intake stroke increases, and the intake air amount is adjusted by feedback control of the throttle opening. On the other hand, in the case of normal idling after warm-up when the engine water temperature is high, in order to reduce the target intake stroke amount while focusing on thermal efficiency, to increase the engine compression ratio, and to secure a desired intake air amount, The throttle opening is increased as the intake stroke decreases, and the intake air amount is adjusted by feedback control of the piston motion (intake stroke). That is, the first setting H1 of the large intake stroke amount and the low compression ratio is set at the high idle during the warm-up operation, and the third setting H3 of the small intake stroke amount and the high compression ratio is set at the normal idling after the warm-up. .

  In this way, at the time of idling, the compression ratio is lowered when the engine is not warmed up, and the compression ratio is increased as the warming up proceeds. Therefore, the exhaust loss increases as the engine is not warmed up. It is possible to promote early activation of the catalyst provided in the exhaust system. Further, when the engine is not warmed up, the intake stroke is increased to decrease the throttle valve opening, thereby increasing the intake negative pressure to promote fuel atomization and improving the exhaust performance.

  Referring again to FIG. 5, in the normal target value calculation unit (target value calculation means) B2, the target throttle opening (tTVO) and the target intake stroke amount in the normal engine operation state excluding the engine start state and the idle state described above. (TSt) and the target compression ratio (tε) are calculated and set based on the accelerator opening (APO) and the engine speed (Ne). As an example, it can be obtained by using a preset control map.

  The operation state determination unit B3 determines whether the engine is in the start state, the idle state, or the normal state based on the accelerator opening (APO), the engine speed (Ne), the starter SW signal, and the like. For example, it can be determined by the routine of FIG. In step S11, it is determined whether a starting condition is satisfied. For example, if the starter SW signal is ON and the engine speed Ne exceeds a predetermined value (for example, about 500 rpm), it is determined that the start condition is satisfied, and the process proceeds from step S11 to step S12. Judge that there is. If the start condition is not satisfied, the process proceeds from step S11 to step S13 to determine whether the idle condition is satisfied. For example, if the accelerator opening APO is less than a predetermined value (for example, about 0.5 deg) and the engine speed Ne is less than a predetermined value (for example, about 1500 rpm), the idle condition is established and the idle state is established. (Step S14), and if the idle condition is not satisfied, it is determined that the engine is in a normal engine operation state excluding engine start and idle (step S15).

  Referring to FIG. 5 again, the final target value setting unit (target value calculation means) B4 uses the results obtained in the above B1 to B3, and uses the target intake stroke amount (tSt) according to the current operating state. The combination of the target compression ratio (tε) and the target throttle opening (tTVO) is output. In the target position calculation unit (target position calculation means) B5, the target intake stroke amount (tSt) and the target compression ratio (tε) output from the final target value setting unit B4, as well as the crank angle and the cylinder discrimination result, etc. Then, the target position of the link support portion 26 of each cylinder is obtained. Based on this target position, the link support portion 26 of each cylinder is driven and controlled.

  The target position of the link support portion 26 at the normal time can be obtained, for example, by a routine shown in FIG. This routine is stored in the control unit 40 and is repeatedly executed every very short predetermined period (for example, 10 ms or a predetermined crank angle). In step S41, a crank angle, a target intake stroke amount, a target compression ratio, and the like are read. The target intake stroke amount and the target compression ratio can be obtained based on the accelerator opening and the engine speed with reference to a preset control map as shown in FIGS. As shown in FIG. 13, the target intake stroke amount is set higher as the accelerator opening degree becomes higher. Further, as shown in FIG. 14, the target compression ratio is set so as to decrease as the accelerator opening degree increases and to increase as the engine speed increases.

  In step S42, a target intake bottom dead center position (target BDC position) and a target compression top dead center position (target TDC position) are obtained based on the target intake stroke amount and the target compression ratio. Note that the expansion BDC and the exhaust TDC may be variable according to the accelerator opening and the engine speed, or may be unchanged as in the first to third settings H1 to H3 described above. Note that the target BDC position and the target TDC position may be set directly based on the accelerator opening and the engine speed more simply.

  In step S43, a target piston position (target piston motion) is set based on the target TDC position and the target BDC position. The target piston position is set to a characteristic close to a sine wave as shown in FIG. 15, for example, so as to pass through the target TDC position and the target BDC position and the piston speed does not change excessively.

  In step S44, the target position of the link support portion 26 is obtained based on the target piston position. As an example, as shown in FIG. 16, a control map showing the relationship between a preset piston position for each crank angle and the position of the link support portion 26 is referred to, and based on the crank angle and the target piston position. Thus, the target position of the link support portion 26 can be obtained. As shown in the figure, in this example, the target position of the link support portion 26 is set to the side toward the upper limit position as the target piston position becomes lower.

  FIG. 17 is a flowchart showing an example of setting control of the basic target throttle opening, and the basic target throttle opening is corrected in accordance with the target intake stroke amount in the target value calculation units B1 and B2. . In step S51, the accelerator opening and the engine speed are read. In step S52, the basic target throttle opening is set with reference to a preset control map (see FIG. 18) based on the accelerator opening and the engine speed. As shown in FIG. 18, the basic target throttle opening is increased in proportion to the accelerator opening, and is fully opened in a region equal to or greater than the predetermined accelerator opening.

  FIGS. 19 to 22 show setting examples in a transient state in which the engine start state is shifted to the idle state according to the present embodiment. In the figure, (A) is the starter SW signal, (B) is the engine speed Ne, (C) is the (target) intake stroke amount, (D) is the (target) compression ratio, and (E) is the intake negative pressure. ing.

  In a state before warm-up in which the state of the battery 52 is good (voltage is normal) and the engine temperature is low and the warm-up operation needs to be performed, as shown in FIG. 19, the intake stroke extends from the engine start state to the idle state. By increasing the amount, the throttle opening is relatively reduced, and in particular, the suction negative pressure in the idle state is secured to promote fuel atomization and the compression ratio is lowered to promote warm-up. .

  In a state after warm-up in which the state of the battery 52 is good (voltage is normal) and the engine temperature is high and the warm-up operation is not required, the intake stroke amount is reduced from the start state to the idle state as shown in FIG. By reducing the friction loss, the friction loss is reduced, the throttle opening is relatively increased to reduce the pump loss, and the compression ratio is increased to improve the thermal efficiency.

  In a pre-warm-up situation where the battery condition is poor (voltage is low) and the engine temperature is low and it is necessary to perform warm-up operation, as shown in FIG. In addition to reducing the throttle opening, reducing the pump loss by reducing the pump loss, ensuring engine startability, and increasing the intake stroke when shifting to the idle state, the throttle opening is relatively reduced. In addition, fuel atomization is promoted by ensuring the suction negative pressure. Further, the engine compression ratio is kept low from the engine start state to the idle state in order to reduce cranking torque and promote warm-up.

  In a situation after the warm-up in which the battery state is poor (voltage is low) and the engine temperature is high and the warm-up operation is not required, the intake stroke amount is reduced from the engine start state to the idle state as shown in FIG. While maintaining and reducing friction, the pump loss is reduced by reducing the suction negative pressure by relatively increasing the throttle opening. Further, the engine compression ratio is lowered in the engine starting state to reduce the cranking torque, and is increased in the idle state to improve the thermal efficiency.

  The characteristic technical idea of the present invention that can be understood from the above description will be described with reference to the illustrated embodiments.

  (1) A four-cycle reciprocating internal combustion engine according to the present invention is a multi-link type in which a control link 25 is connected to one of a plurality of links 23 and 24 that link a piston 12 and a crankpin 22 of a crankshaft 11. The piston motion can be changed according to the engine operating state by controlling the operation of the actuator 27 having the piston-crank mechanism 21 and changing / holding the position of the link support portion 26 of the control link 25 by the control portion 40. is there. Then, target value calculation means (target value calculation unit B1) that calculates a target compression ratio that depends on the position of the compression top dead center and a target intake stroke amount corresponding to the length of the intake stroke according to the engine operating state. , B2 and final target value setting unit B4), target position setting means (target position setting unit B5) for setting the target position of the link support unit 26 based on the target compression ratio and the target intake stroke amount, It is characterized by having.

  (2) An electronically controlled throttle valve 41 for opening and closing the intake passage 16 is provided, and the target throttle opening is set according to the target intake stroke amount so that the target throttle opening becomes smaller as the target intake stroke amount becomes larger. Set.

  (3) A starter 49 that rotationally drives the crankshaft 11 when the engine is started, a battery 52 that supplies electric power to the starter 49, and a battery state detection means (battery controller 53) that detects the state of the battery 52 are provided. At least when the engine is started, the target compression ratio and the target intake stroke amount are set based on the state of the battery 52.

  (4) At the time of cold start when the engine temperature is low, the target intake stroke amount is mainly set to the state of the battery 52 among the target compression ratio and the target intake stroke amount so that the intake stroke amount decreases as the power supplied to the battery 52 decreases. Increase or decrease depending on

  (5) At the time of start-up after warm-up when the engine temperature is high, the target compression ratio is mainly set to the state of the battery 52 out of the target compression ratio and the target intake stroke amount so that the target compression ratio decreases as the power supplied to the battery 52 decreases. Increase or decrease depending on

  (6) At least during idling, a target compression ratio and a target intake stroke amount are set according to the engine temperature.

  (7) During idling, the target intake stroke amount is increased and the target compression ratio is decreased as the engine temperature decreases.

  (8) The setting by the target position setting means is a first setting H1 that realizes piston stroke characteristics close to simple vibration, and a second setting that has a longer intake stroke and a higher compression top dead center position than the first setting H1. And a third setting H3 in which the length of the intake stroke is equivalent to the second setting H2 and the compression top dead center position is higher than the second setting H2.

  (9) In the control method for a 4-cycle reciprocating internal combustion engine capable of controlling the intake stroke amount corresponding to the intake stroke and the compression ratio depending on the position of the compression top dead center, the engine is started based on the engine operating state. The degree of ease of starting the engine is detected, and the intake stroke amount is increased or decreased according to the degree of ease of starting the engine so that the higher the degree of ease of starting the engine, the larger the amount of intake stroke. The degree of ease of starting the engine can be obtained from, for example, the engine water temperature (engine temperature) detected by the water temperature sensor 46, the supply voltage of the battery 52 detected and monitored by the battery 52, and the lower the engine water temperature, The lower the supply voltage of the battery, the lower the degree of ease of starting the engine and the more difficult it is to start the engine.

  As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes without departing from the spirit of the present invention. . For example, in the above-described embodiment, the water temperature sensor 46 that detects the cooling water temperature is used to detect the engine temperature. However, the oil temperature sensor that detects the temperature of the engine oil is used alone or in combination with the water temperature sensor 46 to control the engine temperature. You may make it ask.

The block diagram which shows the control system of the reciprocating type internal combustion engine which concerns on one Example of this invention. The block diagram which shows the multiple link type piston-crank mechanism of the said Example. The characteristic view which shows the example of 1 setting of the target position of the link support part with respect to a crank angle. The characteristic view which shows the piston motion in the 1st-3rd setting of the said link support part. The block diagram which shows typically the setting process of the target position of the link support part which concerns on a present Example. (A) is a characteristic diagram showing the relationship of fuel spray loss to intake stroke (amount), (B) is a characteristic diagram showing the relationship of warm-up performance, thermal efficiency and motoring torque to the compression ratio. The characteristic view which shows an example of the setting at the time of starting. The table which shows an example of the setting at the time of starting. The characteristic view which shows an example of the setting at the time of idling. The table which shows an example of the setting at the time of idle. The flowchart which shows an example of the determination routine of an engine operation state. The flowchart which shows the setting routine of the target position of a link support part. FIG. 13 is a characteristic diagram showing an example of a control map used for setting a target intake stroke amount in the routine of FIG. 12. The characteristic view which shows an example of the control map used for the setting of the target compression ratio by the routine of FIG. The characteristic view which shows an example of a target piston position. The characteristic view which shows the relationship between a target piston position and the target position of a link support part. The flowchart which shows the flow of a calculation process of a basic target throttle opening. The characteristic view which shows the relationship between an accelerator opening and a throttle opening. The time chart which shows the condition of engine start-idle before battery warming is good and warming up. The time chart which shows the condition of engine start-idle after a battery condition is favorable and warming up. The time chart which shows the condition of engine start-idle before a battery condition is bad and warming up. The time chart which shows the condition of the engine start-idle transition period after a battery condition is bad and warming up.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Crankshaft 12 ... Piston 13 ... Cylinder 21 ... Double link type piston-crank mechanism 22 ... Crank pin 23 ... Lower link 24 ... Upper link 25 ... Control link 26 ... Link support part 27 ... Actuator 40 ... Control part 49 ... Starter 52 ... Battery 53 ... Battery controller (battery state detection means)

Claims (9)

An actuator having a multi-link type piston-crank mechanism in which a control link is connected to one of a plurality of links linking a piston and a crank pin of a crankshaft, and changing and holding the position of a link support portion of the control link. In a control apparatus for a four-cycle reciprocating internal combustion engine in which piston motion can be changed by controlling operation,
Target value calculating means for calculating a target compression ratio depending on the position of the compression top dead center and a target intake stroke amount corresponding to the length of the intake stroke according to the engine operating state,
Target position setting means for setting a target position of the link support portion based on the target compression ratio and the target intake stroke amount;
A control apparatus for a reciprocating internal combustion engine, comprising: It has an electric throttle valve that opens and closes the intake passage,
The target value calculating means sets the target throttle opening according to the target intake stroke amount so that the target throttle opening becomes smaller as the target intake stroke amount becomes larger. Control device for reciprocating internal combustion engine. A starter that rotationally drives the crankshaft when the engine is started, a battery that supplies electric power to the starter, and a battery state detection unit that detects the state of the battery,
The control of the reciprocating internal combustion engine according to claim 1 or 2, wherein the target value calculation means sets a target compression ratio and a target intake stroke amount based on the state of the battery at least at the time of engine start. apparatus.   The target value calculation means mainly determines the target intake stroke amount among the target compression ratio and the target intake stroke amount so that the intake stroke amount decreases as the supplied power of the battery decreases during cold start when the engine temperature is low. The control device for a reciprocating internal combustion engine according to claim 1, wherein the control device increases or decreases in accordance with the state of the engine.   The target value calculation means mainly determines the target compression ratio among the target compression ratio and the target intake stroke amount so that the target compression ratio becomes lower as the power supplied to the battery becomes lower at the start after warm-up when the engine temperature is high. The control device for a reciprocating internal combustion engine according to claim 4, wherein the controller increases or decreases according to the state of the engine.   6. The control of a reciprocating internal combustion engine according to claim 1, wherein the target value calculation means sets a target compression ratio and a target intake stroke amount according to the engine temperature at least during idling. apparatus.   The reciprocating internal combustion engine according to any one of claims 1 to 6, wherein the target value calculating means increases the target intake stroke amount and lowers the target compression ratio as the engine temperature decreases during idling. Control device.   The setting by the target position setting means is a first setting that realizes a piston stroke characteristic close to simple vibration, a second setting that has a longer intake stroke and a higher compression top dead center position than the first setting, The length of a stroke is equivalent to a 2nd setting, and the compression top dead center position contains the 3rd setting still higher than a 2nd setting, The any one of Claims 1-7 characterized by the above-mentioned A control device for a reciprocating internal combustion engine according to claim 1. In a control method for a 4-cycle reciprocating internal combustion engine capable of controlling an intake stroke amount corresponding to an intake stroke and a compression ratio depending on the position of compression top dead center,
When starting the engine, it detects the ease of starting the engine based on the engine operating state,
A control method for a reciprocating internal combustion engine, wherein the intake stroke amount is increased / decreased according to the ease of engine start so that the intake stroke amount increases as the engine start ease increases.

Images