JP2007291930A - Internal combustion engine and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine enabling to accurately acquire internal combustion engine torque. <P>SOLUTION: In the internal combustion engine provided with a multi-link mechanism 20, the multi-link mechanism 20 includes an upper link of which one end is rotatably connected to a piston 3, a lower link which another end of the upper link is rotatably connected to and which is rotatably attached to a crank pin 9a of a crank shaft 9, a link 8 of which one end is rotatably connected to the lower link, and an actuator 10 which another end of the link 8 is rotatably connected and which oscillatably supports another end position of the link, and a torque estimation means estimating another end position acting stress acting on an another end of the link 8 and internal combustion engine torque generated by the internal combustion engine according to position of another end of the link 8 and crank angle is included. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine having a so-called multilink capable of changing piston motion and a control method thereof.

  In Patent Document 1, the other end of the first connecting rod whose one end is connected to the piston is connected to the slider guided by the guide portion whose offset amount changes with respect to the cylinder axis, and one end is connected to the first connecting rod. By connecting the other end of the connected second connecting rod to the crankshaft and changing the position of the other end of the first connecting rod connected to the slider, the position of the top dead center and the bottom dead center of the piston is changed. An internal combustion engine in which the compression ratio of the engine is changed is disclosed. Further, Patent Document 1 also discloses a technique for performing cylinder deactivation by moving the fixed position of the guide member to a predetermined position according to the engine speed and load.

In the case of a general premixed spark ignition internal combustion engine, in order to perform shaft torque control, that is, control of torque generated by the internal combustion engine, intake air amount (throttle opening, valve lift amount, ignition timing) and combustion (fuel) The injection amount was adjusted.
JP 2005-140108 A

  However, in the conventional internal combustion engine as disclosed in Patent Document 1, the link mechanism disposed between the piston and the crankshaft can cope with the dimensional change or deformation of the member due to the wear or thermal expansion of the member. Since it is not configured, there is a possibility that shaft torque fluctuation and friction loss may occur due to the piston moving when the cylinder is deactivated. Since it is difficult to accurately grasp the shaft torque, when a shift request, an engine brake request, or the like is generated, there is a possibility that control cannot be performed without responding to changes in the shaft torque.

  Therefore, the present invention provides an internal combustion engine having a multi-link mechanism that connects a piston that reciprocates in a cylinder to a crankshaft via a plurality of links, and the multi-link mechanism has one end rotatably connected to the piston. An upper link, the other end of the upper link being rotatably connected, and a lower link rotatably attached to the crank pin of the crankshaft, and a rocker having one end rotatably connected to the lower link. The other end of the swing link is rotatably connected to the other end of the swing link and rotatably supports the position of the other end of the swing link. The other end position swinging means is used to change the piston motion, and the other end position acting stress acting on the other end of the swing link Depending on the position and the piston crank angle of the swing link and the other end, it is characterized by having a torque estimating means for estimating an internal combustion engine torque generated in the internal combustion engine.

  According to the present invention, when estimating the internal combustion engine torque, the internal combustion engine torque is estimated from the state of the swing link linked to the crankshaft. Therefore, the internal combustion engine torque can be estimated with high accuracy.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  1 and 2 are explanatory views schematically showing an example of an internal combustion engine to which the present invention is applied.

  The internal combustion engine includes an intake valve 1 that opens and closes the intake flow on the intake pipe side, an exhaust valve 2 that opens and closes the exhaust flow on the exhaust pipe side, and a piston 3 that reciprocates in the cylinder and transmits the explosion force in the cylinder to the link. And a crankshaft 9 for transmitting combustion power to the power transmission shaft of the transmission or clutch.

  The piston 3 and the crankshaft 9 are linked via a multi-link mechanism 20 that is a multi-link type piston crank mechanism having a plurality of links.

  The multi-link mechanism 20 is an upper link whose one end is rotatably connected to the piston 3, one end is rotatably connected to the other end of the link 4, and the other end is rotated to the crank pin 9 a of the crankshaft 9. A link 5 that is freely connected, a link 6 that has one end rotatably connected to the other end of the link 4, and one end that is rotatably connected to the crank pin 9 a along with the other end of the link 5. A link 7 that is rotatably connected to the other end of the link 6, a link 8 that has one end rotatably connected to the link 7 and the other end of the link 6, and a link 8 that is rotatable to the other end of the link 8. , And an actuator 10 as other end position swinging means that supports the other end position of the link 8 so as to be changeable (changeable).

  Here, both ends of the link 5, the link 6 and the link 7 are connected to each other, and the triangular shape formed by the link 5, the link 6 and the link 7 is always constant regardless of the reciprocating motion of the piston 3. It is. That is, the link 5, the link 6 and the link 7 can be regarded as a single link functionally. Here, the link corresponding to (replaces) the link 5, the link 6 and the link 7 is defined as a lower link for convenience. In other words, using the lower link, the multi-link mechanism 20 includes the link 4 having one end rotatably connected to the piston 3 and the other end of the link 4 rotatably connected. The lower link rotatably attached to the crank pin 9a of the crankshaft 9, the link 8 having one end rotatably connected to the lower link, the other end of the link 8 being rotatably connected, and the other end of the link 8 The other end position swinging means for supporting the position so as to be swingable, and the piston motion can be changed by swinging the other end position of the link 8 by the actuator 10. Has been.

  The internal combustion engine includes a flywheel 11 that smoothes shaft torque fluctuations due to combustion power, that is, internal combustion engine torque generated in the internal combustion engine, and an ignition device 12 that sparks the sucked air-fuel mixture to obtain explosive power. It has.

  When the throttle opening (opening of a throttle valve (not shown)) changes according to APO (accelerator pedal opening), the intake flow rate according to the throttle opening is obtained. The fuel injection amount is defined according to the intake flow rate, and a desired air / fuel mixing ratio is obtained. When the intake valve 1 is opened, the air-fuel mixture corresponding to the piston stroke is filled into the cylinder.

  Since the air-fuel mixture is an incompressible fluid, the filling amount with respect to the piston stroke is not necessarily proportional. In particular, when the rotation speed is high or the piston speed is fast, the operation of the intake valve 1 is preferably performed in accordance with the inertia of the mixture because it is affected by the inertia of the mixture. The charged air-fuel mixture is ignited and burned by the spark plug 12 when the position of the latter piston 3 is near TDC (top dead center) in the compression stroke.

  The in-cylinder pressure and the working gas temperature increase in accordance with the combustion speed, and a highly efficient internal combustion engine is obtained by appropriately controlling the in-cylinder pressure and the working gas temperature. That is, the internal combustion engine shown in FIGS. 1 and 2 shows a mechanism example that can control the in-cylinder pressure and the working gas temperature by the piston motion. The expansion energy of the working gas is transmitted to the crankshaft 9 by the link 4, the link 5, the link 6, the link 7, and the link 8. The expansion energy transmitted to the crankshaft 9 varies depending on the operation amount of the actuator 10.

  When the expansion stroke ends, the process proceeds to the exhaust stroke. The working gas is exhausted by opening the exhaust valve 2 when the piston position in the initial stage of the exhaust stroke is near TDC or the piston position in the latter half of the expansion stroke is near BDC (bottom dead center).

  The reason that the exhaust valve 2 is opened when the piston position in the latter half of the expansion stroke is in the vicinity of BDC is that the scavenging effect is improved at a high speed. The timing when the exhaust valve 2 is opened is preferably changed according to the rotational speed or piston speed of the internal combustion engine, and the efficiency of the internal combustion engine is further improved by changing it according to the EGR rate and the combustion state.

  The exhaust valve 2 is closed near the TDC in the latter half of the exhaust stroke or near the TDC in the initial intake stroke. That is, the internal combustion engine of the present embodiment is a four-cycle internal combustion engine that generates power by repeating the above intake, compression, expansion, and exhaust. The present invention makes it possible to control the shaft torque by controlling the actuator 10 with the expansion energy transmitted to the crankshaft 9. That is, the internal combustion engine torque generated in the internal combustion engine is variably controlled by swinging the other end position of the link 8 corresponding to the swing link of the multi-link mechanism 20.

  FIG. 3 shows piston motion in the internal combustion engine of FIG. 1 to which the present invention is applied. The characteristic line L1 in FIG. 3 indicates the piston when the actuator 10 in FIG. 1 is the link support position end in the same direction as the direction of change of the piston 3, that is, the other end position of the link 8 is located at the lowest position in FIG. It is motion. A characteristic line L2 is a piston motion when the actuator 10 of FIG. 1 is a link support position end opposite to the direction of change of the piston 3, that is, when the other end position of the link 8 is located at the uppermost position in FIG. A region between L1 and L2 is a piston motion obtained by operating the actuator 10.

  FIG. 4 shows the displacement of the actuator 10 which is a support position when the cylinder deactivation that is the piston motion indicated by the broken line L3 in FIG. 3 is performed. As shown in FIG. 4, when the cylinder is deactivated, the movement (reciprocating motion) of the piston 3 in the cylinder stops. At this time, the crankshaft 9 is at a constant rotational speed.

  FIG. 5 shows a control block diagram of the internal combustion engine according to the present invention.

  A block (hereinafter simply referred to as B) 101 that is an internal combustion engine changes the throttle opening according to APO, and increases or decreases the amount of air-fuel mixture sucked into the cylinder according to the throttle opening. The air-fuel mixture filled in is burned. In the internal combustion engine (B101), the piston motion is changed by changing the position of the other end of the link 8 of the multi-link mechanism 20 as described above.

  B102 is a shaft torque estimating device as torque estimating means for estimating the torque generated in the internal combustion engine. The shaft torque estimation device estimates the shaft torque, that is, the internal combustion engine torque generated in the internal combustion engine, according to the other end position acting stress acting on the other end of the link 8, the position of the other end of the link 8, and the piston crank angle. .

  B106 is a cylinder deactivation determination device that is a cylinder deactivation determination unit that performs cylinder deactivation determination from APO, vehicle speed, and crank angle, and B105 is an engine brake that is an engine brake request determination unit that determines engine brake request from APO and vehicle speed. It is a request determination device. B104 is a shift request determination device which is a shift request determination means for determining a shift request from the APO and the vehicle speed.

  B103 is the other end position control device which is the other end position control means. The other end position control device (B103) includes values of the internal combustion engine speed, piston position, vehicle speed, and APO, cylinder deactivation determination from the cylinder deactivation determination device (B106), and engine brake request determination device (B105). The control command value is output to B107 corresponding to the actuator 10 using the determination results of the engine brake request determination and the shift request determination from the shift request determination device (B104). The control command value output from the other end position control device (B103) is the support stress (actuator torque) at the other end of the link 8 by the actuator 10, in other words, the other end position acting stress acting on the other end of the link 8. . The other end of the link 8 is supported by the other end position acting stress, and the support position is changed based on the other end position acting stress.

  More specifically, when APO changes and the amount of air-fuel mixture charged in the cylinder changes, the power generated in the internal combustion engine (B101) changes. The actuator 10 disposed in the multi-link mechanism 20 changes the other end position of the link 8 in order to realize a desired piston motion.

  The shaft torque estimation device (B102), the other end position control device (B103), the shift request determination device (B104), the engine brake request determination device (B105), and the cylinder deactivation determination device (B106) are substantially each of them. The software is included in an ECM (engine control module) (not shown) that controls the operation of the internal combustion engine. The ECM includes a detection signal of an accelerator opening sensor (not shown) for detecting an accelerator pedal opening, a detection signal of a crank angle sensor (not shown) for detecting a crank angle, and a vehicle speed for detecting a vehicle speed. A detection signal of a sensor (not shown), a detection signal of a piston position detection sensor (not shown) for detecting the piston position, and the like are input.

  A force corresponding to the in-cylinder pressure generated in the piston 3 and the piston crank angle is generated at the other end of the link 8, and the actuator 10 generates torque to maintain the other end support position of the link 8. Actuator torque as the other end position acting stress generated to hold the support position of the other end of the link 8, the support position of the other end of the link 8, the piston position determined by the crank angle, the crank angle and the rotational speed of the internal combustion engine, Then, the shaft torque estimating device (B102) estimates the shaft torque generated in the internal combustion engine (B101), and outputs the estimated shaft torque (shaft torque estimated value).

  The cylinder deactivation determination device (B106) executes cylinder deactivation determination according to the change in APO and vehicle speed, and the result of cylinder deactivation determination is output. Similarly, engine brake request determination is executed by the engine brake request determination device (B105) according to the APO and the vehicle speed, and the determination result is output. Further, a shift request determination is executed by the shift request determination device (B104) according to changes in APO and vehicle speed, and a determination result is output.

  The cylinder deactivation determination, engine brake request determination, and shift request determination are input to the other end position control device (B103), and the other end position acting stress generated by the actuator 10 in the other end position control device (B103) is calculated. And output as a control command value.

  The actuator 10 operates so as to generate the other end position acting stress according to the control command value. The actuator 10 is specifically an electric motor or a hydraulic actuator, and converts the other end position acting stress at the other end of the link 8 from the torque of the electric motor or the hydraulic pressure of the hydraulic actuator. For the conversion, in the case of an electric motor, the other end position acting stress is calculated using a reduction ratio between the electric motor and the other end of the link 8. When the hydraulic actuator is a hydraulic motor, the other end position acting stress is similarly calculated using the reduction ratio between the hydraulic motor and the other end of the link 8. When the hydraulic actuator is a hydraulic cylinder, the other end position acting stress is calculated from the lever ratio between the hydraulic cylinder and the other end of the link 8. In addition, the actuator 10 in this embodiment shall use an electric motor as the drive source.

  FIG. 6 shows an example of the actuator 10. The actuator 10 includes a rack 13 that is rotatably joined to a rotatable portion that is the other end of the link 8 that is rotatably joined to a joining point of the link 6 and the link 7, and a pinion 14 that linearly moves the rack 13. A motor (not shown) joined to the pinion 14 and an actuator driver 15 that forms a feedback loop based on current and position to the motor. By moving the rack 13 linearly, the other end of the link 8 joined to the rack 13 also moves linearly. The support torque as the control command value determined by the other end position control device (B103) is input to the actuator driver 15. The actuator driver 15 applies a current as a support torque to the motor. The change angle of the motor rotor that changes with the torque based on the current is detected and fed back to the actuator driver 15. This series of current control is generally vector control of an AC motor. The relationship between the actuator torque (motor torque) and the control command value is expressed by the following equation (1) when a reduction gear is provided between the motor and the pinion 14.

  Here, ACT_Tr is the actuator torque [Nm], T_Tr is the support torque [Nm] as the control command value, and ACT_Gr is the reduction gear ratio.

  The actuator 10 can be miniaturized by increasing the gear ratio ACT_Gr and decreasing the actuator torque, but it is possible to design the vehicle in consideration of the transmission efficiency, size, and weight of the gear. Improves.

  FIG. 7 shows a control block of the shaft torque estimating device (B102). The shaft torque estimation device (B102) includes an actuator torque, a piston crank angle or a piston crank angle, and an axis torque conversion unit (B201) that converts the actuator torque into an axis torque from the actuator position. And a friction loss correction unit (B202) that corrects the friction loss estimated from the rotational speed.

  Here, the actuator position is the position of the other end of the link 8 and, as will be described later, is represented by a position (Xc, Yc) on an arbitrary xy coordinate on a plane orthogonal to the crankshaft axis direction. To do. This actuator position is detected by a sensor or the like, for example.

  FIG. 8 shows a control block corresponding to the friction loss correction unit (B202). The friction loss correction unit (B202) includes a friction correction table (B301) that determines a friction loss (friction loss torque) based on the internal combustion engine speed. More specifically, the friction loss determined by searching the friction correction Table B (301) is subtracted from the shaft torque conversion value calculated by the calculation flow of FIG.

  FIG. 9 shows the friction correction table (B301). As the rotational speed of the internal combustion engine increases, the friction loss tends to increase. This may be a table according to the load of the internal combustion engine or a friction loss MAP according to the rotational speed and load of the internal combustion engine.

  Then, the calculation flow of a shaft torque conversion part (B201) is shown in FIG. In step (hereinafter simply referred to as S) 501, the shaft conversion coefficient La is calculated from the function fa using the actuator position (Xc, Yc) and the crank angle CA as parameters.

  In S502, the force Fc at the other end of the link 8 which is the other end position acting stress is calculated from the actuator torque Ta, the gear ratio Rg to the other end of the link 8 and the axial radius r of the terminal end, that is, the radius of the pinion 14. In S503, the piston thrust Fp is calculated by the force Fc at the other end of the link 8 calculated in S502 and the shaft conversion coefficient La calculated in S501.

  In S504, the actuator output Wa is calculated from the actuator rotation speed Na and the actuator torque Ta. In S505, the piston position is calculated in time series from Xc, Yc, CA using the function fp. The piston speed is calculated from the piston position P (T) obtained by the calculation of fp, the previous piston position P (t-1), and the sampling time Δt using a difference method.

  In S506, the output Wp generated by the piston is calculated from the piston speed Vp and the piston thrust Fp. In S507, the shaft output We is calculated from the relationship that the piston output Wp is the sum of the shaft output We and the actuator output Wa.

  When calculating the shaft output We, it is preferable to calculate the shaft output We by subtracting it from the shaft output We in consideration of the power of the actuator portion, the friction loss, and the friction loss generated in the piston portion. In S508, the shaft torque Te is calculated from the shaft output We and the shaft rotational speed (internal combustion engine rotational speed) Ne.

  FIG. 11 shows a control block corresponding to the other end position control device (B103).

  The other end position control device (B103) is a cylinder deactivation determination determined by the cylinder deactivation determination device (B106) of FIG. 1, an engine brake request determination and a shift request determination device (B104) determined by the engine brake request determination (B105). The target torque calculation unit (B601) for determining the shaft torque target value from the shift request determination, the internal combustion engine speed, the piston position, and the APO, and the shaft torque target value determined by the target torque calculation unit (B601). On the other hand, it is comprised by the torque controller (B602) which controls an axial torque so that the axial torque estimated value calculated with the axial torque estimation apparatus (B102) of FIG. 1 may become the same value.

  When cylinder deactivation determination, engine brake request determination, shift request determination, internal combustion engine speed and piston position are input to the target torque calculator (B601), a shaft torque target value is output based on each determination.

  The shaft torque target value is input to the torque controller (B602). Further, the estimated shaft torque value is also input to the torque controller (B602), and the control command value is changed so that the deviation between the estimated shaft torque value and the desired shaft torque value becomes small.

  FIG. 12 shows a control block of the torque controller (B602).

A PID control unit (B701) is configured to control the control command value so that the deviation is minimized with a value obtained by subtracting the estimated shaft torque value from the target shaft torque value. In the PID control unit (B701), parameters of the proportional band PB%, the integration time Ti [sec], and the differentiation time Td [sec] in the PID control are adjusted. PID control is calculated by the following equation (2). Δm is added to the value output up to the previous time.
E _n in the formula (2) is the deviation.

  FIG. 13 shows a control block of the target torque calculator (B601). A target torque calculation unit (B601) calculates a cylinder deactivation shaft torque target value calculation unit (B801) that calculates an axis torque target value during cylinder deactivation from the piston position and APO, and an axis torque target value during engine braking from the vehicle speed. An engine brake shaft torque target value calculation unit (B802) for calculating, a transmission shaft torque target value calculation unit (B803) for calculating a shaft torque target value at the time of shift based on the shift request determination and the internal combustion engine speed, and cylinder deactivation Shaft torque target value during engine braking, shaft torque target value during engine braking, shaft torque target value during shifting, cylinder deactivation determination determined by the cylinder deactivation request determination device (B106), and determination by engine brake request determination device (B105) The shaft torque target value is determined based on the determined engine brake request determination and the shift request determination determined by the shift request determination device (B104). Composed of target torque selecting section (B 804).

  The target torque selection unit (B804) selects one target value from among a shaft torque target value during cylinder deactivation, a shaft torque target value during engine braking, and a shaft torque target value during gear shift, and a shaft torque target. Value.

  When the cylinder deactivation shaft torque target value calculation unit (B801), the engine brake shaft torque target value calculation unit (B802), and the transmission shaft torque target value calculation unit (B803) are selected from the target torque selection unit (B804), they are instantaneous. It is preferable that the calculation is always performed so that the target shaft torque value can be output. However, when the calculation load increases, only the target shaft torque calculation selected from the target torque selection unit (B804) may be operated. I do not care.

  FIG. 14 shows a control block of the cylinder deactivation shaft torque target value calculation unit (B801).

  The cylinder deactivation shaft torque target value calculation unit (B801) multiplies B901 that multiplies the gain K1 based on the deviation between the piston position and the BDC position, and multiplies the output of B901 and APO to determine the shaft torque target value. B903 that multiplies the difference between the crank angle of the crank angle and the intake stroke BDC by gain K2 based on the deviation, B905 that converts the output signal from B903 so that it can be added to the output signal from B901, and the output from B905 Is limited only in the direction in which the axial torque becomes the driving force (B904).

  In other words, the cylinder deactivation shaft torque target value calculation unit (B801) outputs B901 that outputs a signal based on the deviation between the piston position and the BDC position, and APO (in this case, the accelerator pedal opening degree) to the signal output from B901. B902 for multiplying by determining the shaft torque target value by multiplying the corresponding signal input), B903 for outputting a signal based on the crank angle deviation between the crank angle and the intake stroke BDC, and the output signal from B901. B905 for converting the output signal from B903, and a limiting unit (B904) that permits the output from B905 only in the direction in which the shaft torque becomes the driving force and adds it to the signal output from B901. .

  When the difference between the piston position and the BDC position is large, the deviation also increases, so the temporary shaft torque target value output from B901 becomes a large value, and the shaft torque changes. The influence of this shaft torque change is determined by the ratio of the piston inertia force torque in the internal combustion engine generated torque.

  Further, when the difference between the crank angle and the intake stroke BDC crank angle becomes large, the shaft torque target value increases, and the shaft torque changes so that the cylinder is deactivated as soon as possible. However, the limiter (B904) may limit the deviation between the crank angle and the intake stroke BDC crank angle so that the change direction of the shaft torque works in the engine braking direction of the vehicle and does not give excessive torque to the vehicle. preferable.

  In a region where the internal combustion engine generated torque is small, that is, when the APO is small, the shaft torque fluctuation increases when attempting to deactivate the cylinder immediately. Therefore, in B902, the shaft torque target value is converted into one corresponding to the APO.

  FIG. 15 shows a control block of the engine brake shaft torque target value calculation unit (B802). The engine brake shaft torque target value calculation unit (B802) converts the driving force Table (B1001) for determining the driving force from the vehicle speed and the driving force output from the driving force Table (B1001) to the shaft torque of the internal combustion engine, An internal combustion engine shaft torque converter (B1002) is used as a shaft torque target value.

  The driving force Table (B1001) is shown in FIG. The driving force by the engine brake generated in the negative direction according to the vehicle speed is shown. The reason that the engine brake tends to decrease as the vehicle speed decreases is to cause the same function as the clutch OFF and the torque converter lockup mechanism OFF.

  The internal combustion engine shaft torque converter (B1002) performs the calculation according to the following equation (3). Gtm is a transmission gear ratio, Gf is a final reduction ratio, Fd is a driving force, Te is an internal combustion engine shaft torque, and Rt is a tire radius.

  FIG. 17 shows a control block of the cylinder deactivation discrimination device (B106). The cylinder deactivation determination device (B106) includes a cylinder deactivation determination table (B1201) that determines cylinder deactivation determination from the APO and the vehicle speed. In the intake stroke determination, when the crank angle is within a predetermined range, it is determined that the intake stroke is in effect. After the intake stroke determination is set to 1, if the determination does not become 1, the following logical expression is established so as not to be reset.

  FIG. 18 shows a cylinder deactivation determination table (B1201). The cylinder deactivation determination is output as 0 or 1, and when the cylinder deactivation determination is 1, the cylinder deactivation is permitted. The reason why the cylinder deactivation range is widened as the APO is low and the vehicle speed is high is that the steady operation is likely to continue for a long time in high-speed traveling, so that the fuel consumption effect can be maximized by deactivating the cylinder. For example, highway traveling is an example.

  This Table setting is preferably set in consideration of the running state, and is preferably set based on market data. In order to prevent hunting, it is preferable to use a switching table having hysteresis with APO to prevent hunting.

  FIG. 19 shows a control block of the engine brake request determination device (B105). The engine brake request determination device (B105) includes an engine brake request determination table (B1401) that determines engine brake request determination from APO and vehicle speed.

  FIG. 20 shows an engine brake request determination table (B1401). The engine brake request determination is output as 0 or 1, and the power running state is 0 output. When the engine brake request determination is 1, the engine brake is permitted.

  As the APO is lower and the vehicle speed is higher, the range of engine brake request determination 1 becomes wider. The reason why the engine brake request determination 1 region is provided in the region where the APO is low is to provide normal internal combustion engine characteristics. Further, the reason why the area of engine brake request determination 1 is wider as the vehicle speed is higher is that there are more opportunities to adjust the vehicle speed with the engine brake as the vehicle speed is higher. For switching the engine brake, it is preferable to use a switching table having hysteresis with APO to prevent hunting.

  FIG. 21 shows a control block of the transmission shaft torque target value calculation unit (B803). The transmission shaft torque target value calculation unit (B803) has B1601 for outputting a shaft torque target value from the deviation between the shift request determination determined by the shift request determination device (B104) and the internal combustion engine speed.

  The greater the difference between the internal combustion engine target speed in the shift request determination and the current internal combustion engine speed, the larger the shaft torque target value, and the desired internal combustion engine speed can be instantaneously achieved. The distance can be shortened.

  FIG. 22 shows a control block of the shift request determination device (B104). The shift request determination device (B104) determines a shift request determination MAP (B1701) for determining a shift speed from the APO and the vehicle speed, and a target internal combustion engine speed that is a shift request determination from the shift speed determined by the shift request determination MAP and the vehicle speed. And an internal combustion engine speed conversion unit (B1702) to be determined.

  FIG. 23 shows the shift request determination MAP (B1701) of FIG.

  The shift request determination MAP can be controlled in synchronization with the internal combustion engine and the transmission by using a MAP similar to the transmission.

  FIG. 24 shows a control flow of the target torque selector (B804).

  In S1901, engine brake request determination is executed. If the engine brake request determination is 1, the process proceeds to S1905. In S1905, the engine brake shaft torque target value is set to the shaft torque target value, and the process ends.

  If it is determined in S1901 that the engine brake request determination is 0, the process proceeds to S1902 to determine cylinder deactivation determination. If it is determined that the cylinder deactivation determination is 1, the process proceeds to S1906, where the cylinder deactivation axis torque target value is set to the target axis torque, and the process ends.

  If it is determined in S1902 that the cylinder deactivation determination is 0, the process proceeds to S1903, and an ascending edge that is a change in the shift request determination is extracted. In S1904, if an edge can be extracted in S1903, the process proceeds to S1907, the transmission shaft torque target value is set to the target shaft torque, and the process ends.

  If the edge cannot be extracted in S1904, the shaft torque is set to a shaft torque corresponding to APO.

  The above-described embodiment is an example of an internal combustion engine to which the present invention is applied. If the combustion power is transmitted to an actuator that changes piston motion, a different mechanism is provided by limiting the control range of the shaft torque. But it is applicable.

  The technical idea of the present invention that can be grasped from the above embodiment will be listed together with the effects thereof.

  (1) In an internal combustion engine including a multilink mechanism that couples a piston that reciprocates in a cylinder to a crankshaft through a plurality of links, the multilink mechanism has an upper end that is rotatably coupled to the piston. A link, a lower link rotatably connected to the other end of the upper link, and a swing link rotatably connected to a crank pin of the crankshaft, and a swing link having one end rotatably connected to the lower link And the other end position swinging means for rotatably supporting the position of the other end of the swing link, the other end of the swing link being rotatably supported, and the position of the other end of the swing link The other end position swinging means swings the piston motion so that the other end position acting stress acting on the other end of the swing link, Depending on the position and the piston crank angle of the link and the other end has a torque estimating means for estimating an internal combustion engine torque generated in the internal combustion engine.

  Thereby, when estimating the internal combustion engine torque, the internal combustion engine torque is estimated from the state of the swing link linked to the crankshaft, so that the internal combustion engine torque can be estimated with high accuracy.

  (2) In the internal combustion engine according to (1), the torque estimation means performs friction correction in consideration of friction loss estimated from the engine speed.

  Thus, if the friction loss is also taken into account, the internal combustion engine torque can be estimated more accurately.

  (3) The internal combustion engine according to the above (1) or (2) has other end position control means for controlling the change of the position of the other end of the swing link by the other end position swing means. The other end position swinging means is controlled by an end position control means, and the position of the other end of the swing link is changed so that the internal combustion engine torque becomes a target torque required according to engine operating conditions.

  Thus, the torque control of the internal combustion engine can be performed more accurately by moving the other end of the swing link to a desired torque.

  (4) In the internal combustion engine according to (3), the other-end position swinging unit is configured so that the estimated torque estimated by the torque estimating unit approaches a target torque required according to an engine operating state. It is controlled by the other end position control means.

  As a result, the estimation and control of the internal combustion engine torque can be performed accurately, and they can be performed basically only by controlling the position of the other end of the swing link.

  (5) The internal combustion engine according to the above (4) has cylinder deactivation determination means for determining whether or not to perform cylinder deactivation with the movement of the piston stopped, and cylinder deactivation is required by the cylinder deactivation determination means. When the cylinder of the internal combustion engine is deactivated, the other end position swinging means is set so that the internal combustion engine torque becomes a cylinder deactivation target torque according to the accelerator opening and the piston position. Thus, the position of the other end of the swing link is variably controlled.

  As a result, stable cylinder deactivation can be performed even when shaft torque fluctuates during cylinder deactivation or when the link length of the multi-link mechanism changes due to thermal expansion or wear. Further, since the cylinder deactivation operation in which the piston itself is deactivated is performed by deactivating the valve by deactivating the valve, the friction loss between the piston and the cylinder wall surface can be reduced, so that the thermal efficiency is improved.

  In addition, in the case of only position control, there is a dead zone due to the influence of the frictional force acting on the piston while the cylinder is deactivated, resulting in non-linearity, so that the control performance is lowered and it is difficult to enter the cylinder deactivated state. Since the force generated in the piston is directly controlled from the estimated torque, the piston can be stably stopped even in the dead zone due to friction.

  (6) In the internal combustion engine according to (5), the cylinder deactivation target torque is set to increase according to a distance from a bottom dead center of the piston.

  As a result, even if the valve is driven during cylinder deactivation, the cost and size of the valve mechanism can be reduced because the piston does not contact the valve.

  (7) In the internal combustion engine according to (5) or (6), the bottom dead center of the piston is a bottom dead center of the intake stroke.

  As a result, the piston staying time at the bottom dead center between the intake stroke and the compression stroke is prolonged, so that vaporization of the air-fuel mixture is promoted, combustion stability is improved from cylinder deactivation to cylinder restart, and HC amount is reduced. .

  (8) The internal combustion engine according to any one of the above (4) to (7) includes a shift request determination unit that determines a shift request of the vehicle. When a shift request is generated, the internal combustion engine torque is The position of the other end of the rocking link is variably controlled by the other end position rocking means so as to be the target torque for shifting request according to the rotational speed.

  As a result, the shaft torque can be adjusted so as to reduce the shift shock due to the shaft torque of the internal combustion engine at the time of shifting.

  (9) In the internal combustion engine described in (8) above, the shift request target torque increases as the shift speed is changed to generate a larger driving force, and decreases as the internal combustion engine speed increases. It is set to be.

  Thus, when the operating rotational speed of the internal combustion engine has a large rotational speed difference between the connecting shaft and the internal combustion engine of the transmission, the rotational speed difference between the transmission and the internal combustion engine can be quickly matched. The speed increases faster than the torque increase, and the shift shock can be reduced.

  (10) In the internal combustion engine according to any one of (4) to (9), the engine includes an engine brake request determining unit that determines whether an engine brake request is generated in the vehicle. The position of the other end of the swing link is variably controlled by the other end position swinging means so that the target torque for engine brake request according to the vehicle speed is obtained.

  Thus, when an engine brake request is generated, an engine brake can be generated in which the braking force fluctuation caused by the fluctuation of the piston negative pressure is smoothed, so that the vibration of the vehicle can be suppressed. Further, it is possible to improve vehicle stability by suppressing tire lock due to engine braking when the road surface friction coefficient is extremely low.

  (11) In the internal combustion engine according to the above (10), the target torque for engine brake request becomes smaller as the gear is changed to a gear position that generates a larger driving force.

  As a result, when the accelerator opening decreases momentarily from the state where a large amount of driving force is generated, even if the road friction coefficient is low, the engine braking can be set small, so that tire lock can be suppressed and vehicle stability can be suppressed. Can be improved.

  (12) An upper link whose one end is rotatably connected to the piston, a lower link which is rotatably connected to the other end of the upper link, and is rotatably attached to a crankpin of the crankshaft, and one end which is A swing link that is rotatably connected to the lower link, and another end position swing means that rotatably connects the other end of the swing link and supports the position of the other end of the swing link so as to be swingable. And having a multi-link mechanism capable of changing the piston motion by swinging the position of the other end of the swing link by the other end position swing means, and acting on the other end of the swing link An internal combustion engine that estimates the torque generated in the internal combustion engine according to the end position acting stress, the position of the other end of the swing link and the piston crank angle, and controls the internal combustion engine based on the estimated torque estimated value Control method.

  Thereby, when estimating the internal combustion engine torque, the internal combustion engine torque is estimated from the state of the swing link linked to the crankshaft, so that the internal combustion engine torque can be estimated with high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the internal combustion engine which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically the internal combustion engine which concerns on this invention. The characteristic line figure which shows the piston motion of the internal combustion engine which concerns on this invention. In the internal combustion engine which concerns on this invention, the characteristic line figure which shows the change of the position of the rocking | fluctuation link other end of a multilink mechanism at the time of cylinder deactivation. The control block diagram of the internal combustion engine which concerns on this invention. Explanatory drawing which showed the specific example of the actuator typically. The control block diagram of an axial torque estimation apparatus. The control block diagram of a friction loss correction | amendment part. Friction correction table for calculating friction loss. The flowchart which shows the flow of control performed in a shaft torque conversion part. The control block diagram of an other end position control apparatus. The control block diagram of a torque controller. The control block diagram of a target torque calculating part. The control block diagram of a cylinder deactivation axis torque target value calculating part. The control block diagram of an engine brake shaft torque target value calculating part. Driving force table used when determining driving force from vehicle speed. The control block diagram of a cylinder deactivation discrimination apparatus. Cylinder deactivation determination table used when performing cylinder deactivation determination. The control block diagram of an engine brake request | requirement determination apparatus. Engine brake request determination table used when engine brake request determination is performed. The control block diagram of a transmission shaft torque target value calculating part. FIG. 3 is a control block diagram of the shift request determination device. Shift request determination MAP used when performing shift request determination. The flowchart which shows the flow of control performed by the target torque selection part.

Explanation of symbols

3 ... Piston 4 ... Link (Upper link)
8 ... Link (oscillating link)
9 ... Crankshaft 10 ... Actuator 20 ... Multi-link mechanism

Claims (12)

In an internal combustion engine having a multi-link mechanism for connecting a piston that reciprocates in a cylinder to a crankshaft via a plurality of links,
The multi-link mechanism includes an upper link having one end rotatably connected to the piston and a lower end rotatably connected to the crank pin of the crankshaft while the other end of the upper link is rotatably connected. A link, a swing link having one end rotatably connected to the lower link, and the other end rotatably connected to the other end of the swing link and rotatably supporting the position of the other end of the swing link. An internal combustion engine having a position swinging means, wherein the piston motion can be changed by swinging the position of the other end of the swing link by the other end position swinging means,
There is provided torque estimation means for estimating the internal combustion engine torque generated in the internal combustion engine according to the other end position acting stress acting on the other end of the swing link, the position of the other end of the swing link and the piston crank angle. An internal combustion engine characterized by the above.   2. The internal combustion engine according to claim 1, wherein the torque estimation means performs friction correction in consideration of friction loss estimated from the engine speed.   The other end position swinging means controls the change of the other end position of the swing link, and the other end position swinging means controls the other end position swinging means, The internal combustion engine according to claim 1 or 2, wherein the position of the other end of the swing link is changed so that the engine torque becomes a target torque required according to engine operating conditions.   The other end position swinging means is controlled by the other end position control means so that the estimated torque estimated by the torque estimating means approaches the target torque required according to the engine operating state. The internal combustion engine according to claim 3.   A cylinder deactivation determination unit that determines whether or not to perform cylinder deactivation when the movement of the piston is stopped. When the cylinder deactivation determination unit determines that cylinder deactivation is necessary, the cylinder of the internal combustion engine The position of the other end of the swing link is variably controlled by the other end position swinging means so that the internal combustion engine torque becomes the target torque for cylinder stop according to the accelerator opening and the piston position during the stop. The internal combustion engine according to claim 4, wherein   6. The internal combustion engine according to claim 5, wherein the cylinder deactivation target torque is set so as to increase according to a distance from a bottom dead center of the piston.   The internal combustion engine according to claim 6, wherein the bottom dead center of the piston is a bottom dead center of an intake stroke.   Shift request determination means for determining a shift request of the vehicle is provided, and when the shift request is generated, the other end position fluctuation is adjusted so that the internal combustion engine torque becomes the target torque for shift request according to the engine speed. The internal combustion engine according to any one of claims 4 to 7, wherein the position of the other end of the swing link is variably controlled by a moving means.   9. The shift request target torque is set so as to increase as the gear position is changed to generate a larger driving force, and to decrease as the internal combustion engine speed increases. The internal combustion engine described in 1.   An engine brake request determination unit is provided for determining whether an engine brake request for the vehicle is generated. When the engine brake request is generated, the other end position is changed so that the target torque for engine brake request according to the vehicle speed is obtained. The internal combustion engine according to any one of claims 4 to 9, wherein the position of the other end of the swing link is variably controlled by a moving means.   11. The internal combustion engine according to claim 10, wherein the engine brake request target torque becomes smaller as the engine brake is changed to a gear position that generates a larger driving force. An upper link whose one end is rotatably connected to the piston, a lower link which is rotatably connected to the other end of the upper link and which is rotatably attached to a crank pin of the crankshaft, and one end which is the lower link A swing link that is rotatably connected to the other end of the swing link, and another end position swinging means that rotatably supports the other end of the swing link. And a multi-link mechanism capable of changing a piston motion by swinging the position of the other end of the swing link by the other end position swing means,
The torque generated in the internal combustion engine is estimated according to the other end position acting stress acting on the other end of the swing link, the position of the other end of the swing link and the piston crank angle, and the estimated torque estimated value is obtained. An internal combustion engine control method comprising controlling an internal combustion engine based on the control method.

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