JP2010043551A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine, where the engine includes both of a function for performing a reduced-cylinder operation and a motor-driven variable valve operating device, and which can more stably maintain an engine condition according to each operating state. <P>SOLUTION: The control device is provided to an internal combustion engine 10 including electric-motor-driven variable valve timing devices 270 and 370, and valve drive stopping mechanisms 366 and 386 for stopping drive of engine valve(s) of one or some of cylinders. The control device performs the reduced-cylinder operation by using the valve drive stopping mechanisms 366 and 386 when the internal combustion engine 10 is in a predetermined operating range. In addition, the control device inhibits performing of the reduced-cylinder operation when at least one of that an output voltage of a battery 410 is lower than a predetermined voltage affecting to actuation of the variable valve timing devices 270 and 370, and that a temperature of lubricant of the variable valve timing devices 270 and 370 is lower than a predetermined temperature affecting to the actuation, is met. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  In order to obtain a valve characteristic in accordance with each operation state, an internal combustion engine mounted on a vehicle, in particular, a reduced-cylinder operation in which some of a plurality of cylinders are deactivated in accordance with the operation state of the vehicle. The present invention relates to a control device for an internal combustion engine that controls an engine state through a motor-driven variable valve device.

  Conventionally, for example, an internal combustion engine described in Patent Document 1 is known as an internal combustion engine capable of performing the above-described reduced-cylinder operation while making the valve timing of an engine valve variable. That is, this internal combustion engine includes a variable number of operating cylinders device that varies the number of cylinders in which fuel is burned by stopping the operation of engine valves of specific cylinders according to the operating state of the vehicle, and a camshaft for the crankshaft. And a valve timing varying device that varies the opening timing and closing timing of engine valves such as an intake valve and an exhaust valve by changing the rotation phase of the engine.

  Here, when the combustion of the fuel in only a part of the cylinders of the engine, that is, the reduced cylinder operation is performed by the variable operating cylinder number device, intake and exhaust are not performed in the cylinders that are not in operation. The pumping loss can be reduced accordingly. Further, since the opening / closing operation of the engine valve is also stopped in the non-operating cylinder, the reaction force from the valve spring is reduced corresponding to the number of engine valves whose opening / closing operation is stopped. That is, as compared with the case where all cylinder operation is performed in which combustion is performed in all cylinders, the fuel consumption of the internal combustion engine as a whole is improved by reducing the pumping loss and reducing the reaction force from the valve spring. It will be.

  Further, the variable valve timing device makes it possible to change the opening / closing timing of the engine valve in accordance with the vehicle operating state, particularly the engine speed and the engine load, thereby achieving both an increase in engine output and a reduction in fuel consumption. It will be also.

  Therefore, the cooperation of the variable number of operating cylinders and the variable valve timing device will greatly enhance the performance of the internal combustion engine, including engine output and fuel consumption, and it has a higher degree of freedom according to the driving state of the vehicle. Moreover, efficient engine operation becomes possible.

In recent years, as the valve timing variable device, as described in Patent Document 2, for example, a motor-driven valve timing variable device that can change the rotational phase of the camshaft by an electric motor has been adopted. Yes. In addition, according to such a motor-driven variable valve timing device, it is possible to control the opening / closing timing of the engine valve more finely than in a conventional variable valve timing device using a hydraulic actuator. It has become.
Japanese Patent Laid-Open No. 05-163971 JP 2007-255410 A

By the way, although the reduced cylinder operation of the engine using the variable number of operating cylinders has the advantages as described above, when the reduced cylinder operation is being performed, the combustion state of each of the operating cylinders is the internal combustion engine. Therefore, if any inconvenience that impedes engine operation occurs in these operating cylinders, there is a high possibility that the internal combustion engine will stall. Therefore, especially when such an operating cylinder number variable device is used in combination with a valve timing variable device, even if the motor-driven valve timing variable device having excellent controllability is used, the cam torque change, etc. More precise control that takes into account changes in the operating environment is required.

  The internal combustion engine is not limited to the internal combustion engine of the above type, and includes a motor-driven valve lift variable device that varies the valve lift by an electric motor as a variable valve operating device that can vary the valve characteristics of the engine valve. Alternatively, an internal combustion engine equipped with both the motor-driven variable valve lift amount device and the motor-driven variable valve timing device, or a variable number of operating cylinders can be stopped without stopping the operation of the engine valves. Even in an internal combustion engine that performs a reduced-cylinder operation by stopping combustion injection to a cylinder, such a situation is generally common.

  The present invention has been made in view of the above circumstances, and an object of the present invention is an internal combustion engine that has both a function of performing reduced-cylinder operation and a motor-driven variable valve operating device, each time an operating state. It is an object of the present invention to provide a control device for an internal combustion engine that can maintain a more stable engine state according to the above.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is provided with a variable valve gear that varies the valve characteristic of the engine valve based on driving of an electric motor by power feeding from a vehicle-mounted battery, and when the internal combustion engine is in a predetermined operating region, In a control device for an internal combustion engine that controls the engine state through the variable valve operating device so as to obtain a valve characteristic in accordance with each operation state while performing a reduced-cylinder operation in which a part of the cylinders is in a resting state, The output voltage is equal to or lower than a predetermined voltage that affects the operation of the variable valve device, and the temperature of the lubricating oil that serves as the operating lubricant of the variable valve device affects the operation of the variable valve device. The gist of the invention is to prohibit execution of the reduced-cylinder operation on condition that at least one of the predetermined temperature or lower is satisfied.

  A variable valve gear that varies the valve characteristics of an engine valve is usually composed of a number of members that slide relative to each other during operation. For this reason, the magnitude of the friction generated between these members, in other words, the operability of the variable valve operating device is the temperature determined by the lubricating oil serving as the operating lubricant of the variable valve operating device, that is, the viscosity determined by the same temperature. Dependent. In addition, when this variable valve operating device makes the valve characteristics variable based on the drive of the electric motor, the operability as the variable valve operating device is also the output voltage of the vehicle-mounted battery applied to the electric motor. Also depends. That is, an increase in viscosity due to a decrease in the lubricating oil temperature and a decrease in the output voltage of the in-vehicle battery are major factors that cause a decrease in operability as a variable valve operating device.

  On the other hand, as described above, when the reduced cylinder operation in which some of the plurality of cylinders included in the internal combustion engine are deactivated is performed, the operation state as the internal combustion engine is controlled only by the cylinders operating at this time. become. For this reason, if such reduced cylinder operation is performed under the situation where the properties of the lubricating oil and the output voltage of the on-vehicle battery affect the variable valve operating device as described above, the internal combustion engine may fall into a stall.

In this regard, according to the invention described in claim 1,
(1) The output voltage of the in-vehicle battery is a predetermined voltage range that affects the operation of the variable valve operating apparatus.

(2) The temperature of the lubricating oil serving as the operating lubricant of the variable valve operating device is equal to or lower than a predetermined temperature that affects the operation of the variable valve operating device.
When at least one of the two conditions is satisfied, the execution of the reduced-cylinder operation is prohibited, so the reduced-cylinder operation is performed even though the operability of the variable valve operating device is not ensured. It becomes possible to suppress the destabilization of the engine operation due to the execution, and it is possible to maintain a stable engine state according to the operation state each time.

  The invention according to claim 2 is provided with a variable valve gear that varies the valve characteristic of the engine valve based on driving of the electric motor by power feeding from the vehicle-mounted battery, and when the internal combustion engine is in a predetermined operating region, In a control device for an internal combustion engine that controls the engine state through the variable valve operating device so as to obtain a valve characteristic in accordance with each operation state while performing a reduced-cylinder operation in which a part of the cylinders is in a resting state, The output voltage is equal to or lower than a predetermined voltage that affects the operation of the variable valve device, and the temperature of the lubricating oil that serves as the operating lubricant of the variable valve device affects the operation of the variable valve device. The gist of the invention is to prohibit the execution of the reduced cylinder operation on condition that the variable valve operating device is operating in a state where at least one of the predetermined temperature or lower is satisfied.

  In the present invention, the execution of the reduced cylinder operation is prohibited when the variable valve gear is operating under a situation where at least one of the above conditions (1) and (2) is satisfied. . In other words, even if at least one of the above conditions (1) and (2) is satisfied, if the variable valve operating device is not operating, for example, at a constant speed of the vehicle during idle operation or so-called cruise control. The reduced cylinder operation is not prohibited when the engine operation state is not likely to become unstable even if the reduced cylinder operation is executed even when the reduced cylinder operation is executed, such as during traveling. . Therefore, as in the first aspect, in addition to being able to maintain a more stable engine state according to the operation state of the internal combustion engine in each case, the engine operation state in which execution of the reduced cylinder operation is prohibited is minimized. As a result, the fuel consumption of the internal combustion engine as a whole is further improved.

  Further, according to the invention described in claim 3, as the variable valve operating apparatus described in claim 1 or 2, a variable valve timing device capable of continuously changing the opening / closing timing of the engine valve may be adopted. In addition, as a means for executing the reduced cylinder operation, a valve drive stop mechanism for stopping the opening / closing drive of the engine valve of the cylinder to be stopped is adopted, and the reduced cylinder operation is performed using this valve drive stop mechanism. It is possible to execute. In this case, since the pumping loss as the engine is reduced by the amount of intake and exhaust not being performed in the idle cylinder, fuel efficiency is steadily improved.

  As an internal combustion engine to be controlled, a V-type multi-cylinder internal combustion engine having a V-type cylinder arrangement is particularly effective, for example, according to the invention described in claim 4, and the above-described reduced-cylinder operation is performed. In fact, the control device can be easily designed and realized.

  In this case, in particular, as in the fifth aspect of the invention, when the reduced-cylinder operation is performed, all the cylinders located in one bank of the cylinder groups arranged in the V-type are in the idle state. For example, even when the above valve drive stop mechanism is adopted, it is only necessary to mount this mechanism in one bank that is a target for deactivation (cylinder reduction). This is easier to implement.

[First Embodiment]
Hereinafter, a first embodiment in which a control device for an internal combustion engine according to the present invention is applied to a V-type multi-cylinder internal combustion engine mounted on a vehicle will be described with reference to FIGS.

First, an outline of the internal combustion engine of the present embodiment will be described with reference to FIGS.
FIG. 1 is a schematic diagram showing a schematic configuration of a V-type multi-cylinder internal combustion engine, for example, a V-type 6-cylinder internal combustion engine having three cylinders in one bank and a V-type 8-cylinder internal combustion engine having four cylinders in one bank. It is a block diagram.

  As shown in FIG. 1, the crankcase 100 of the internal combustion engine 10 has an oil pan 110 formed in the lower part thereof, and two cylinder blocks 210 having a plurality of cylinders 211 and 311 in the upper part thereof. 310 is provided so that the angle between the cylinders 211 and 311 is, for example, 60 degrees. In the present embodiment, the row of cylinders 211 arranged in the cylinder block 210 is referred to as the first bank 200, and the row of cylinders 311 arranged in the cylinder block 310 is referred to as the second bank 300.

  The cylinders 211 and 311 are provided with pistons 220 and 320 that reciprocate inside thereof, and the plurality of pistons 220 and 320 are connected to the crankcase via connecting rods 230 and 330 connected thereto, respectively. It is connected to a single crankshaft 120 provided in 100. The cylinders 211 and 311 discharge intake pipes 240 and 340 for introducing a mixture of fuel and air injected by the fuel injection valves 250 and 350, and exhaust generated by the combustion of the mixture. Exhaust pipes 241 and 341 are provided. The intake pipes 240 and 340 and the exhaust pipes 241 and 341 respectively have intake valves 240a and 340a or exhaust ports 241a and 341a, which are connecting portions to the cylinders 211 and 311, as engine valves that can be opened and closed. 264, 364 or exhaust valves 284, 384 are provided. Furthermore, the cylinders 211 and 311 are provided with spark plugs 251 and 351 that emit ignition sparks for igniting the air-fuel mixture introduced from the intake pipes 240 and 340, respectively.

  The intake valves 264 and 364 and the exhaust valves 284 and 384 are biased toward the opposite sides of the cylinders 211 and 311 to keep the intake ports 240a and 340a or the exhaust ports 241a and 341a closed. Valve springs 265, 285, 365, 385 are provided. In addition, these valves 264, 284, 364, 384 are connected to the cylinders 211, 264, 364 and exhaust valves 284, 384 at the ends opposite to the intake ports 240 a, 340 a and exhaust ports 241 a, 341 a. One ends of the rocker arms 262, 282, 362, and 382 pushed down to the 311 side are in contact. On the other hand, the first bank 200 and the second bank 300 are provided with intake camshafts 260 and 360 or exhaust camshafts 280 and 380 that are drivingly connected to the crankshaft 120 via a timing chain (not shown). . The rocker arms 262, 282, 362, and 382 are pushed down by the intake cams 261 and 361 or the exhaust cams 281 and 381 provided on these shafts, so that the urging force of the valve springs 265, 285, 365, and 385 is applied. The engine valve is opened against this. Each of the rocker arms 262, 282, 362, and 382 has a roller 263 that transmits the pressing force to the rocker arms 262, 282, 362, and 382 between the intake cams 261 and 361 or the exhaust cams 281 and 381. , 283, 363, and 383 are provided.

In such an internal combustion engine 10, during operation, an amount of fuel corresponding to the engine operating state is injected into the intake pipes 240 and 340 by the fuel injection valves 250 and 350, and the intake pipes 240 and 340 are injected. It flows into the cylinders 211 and 311 as an air-fuel mixture together with the air inside. The air-fuel mixture is ignited by the sparks of the spark plugs 251 and 351, and combustion occurs. The pistons 220 and 320 in the cylinders 211 and 311 are pushed down by the combustion gas generated at this time. As the pistons 220 and 320 descend in the cylinders 211 and 311 as described above, the linear motion is converted into rotational motion by the connecting rods 230 and 330, and the crankshaft 120 rotates. The rotation of the crankshaft 120 is applied to the crank sprocket provided at one end of the crankshaft 120 and the cam sprocket provided at one end of the intake camshafts 260 and 360 and the exhaust camshafts 280 and 380. By being transmitted to the intake camshafts 260 and 360 and the exhaust camshafts 280 and 380 by the chain, these camshafts 260, 280, 360 and 380 rotate following the rotation of the crankshaft 120. In this way, the camshafts 260, 280, 360, and 380 rotate, and cam noses that are protrusions of the cams 261, 281, 361, and 381 provided on the camshafts 260, 280, 360, and 380 are rollers 263, 283, 363, respectively. When 383 is pressed, the engine valve is pushed down through the rocker arms 262, 282, 362, and 382, and the valve is opened. Thereafter, when the camshafts 260, 280, 360, and 380 further rotate and the base circles of the cams 261, 281, 361, and 381 come into contact with the rollers 263, 283, 363, and 383, the engine valve becomes the valve spring 265. , 285, 365, and 385, the valve is closed.

  On the other hand, as also shown in FIG. 1, the intake camshafts 260 and 360 are connected to one end of the intake camshafts 260 and 360 by the drive of the electric motor, that is, the opening and closing timing of the intake valves 264 and 364, Motor-driven valve timing variable devices 270 and 370 that continuously change the relative rotational phase are provided.

  FIG. 2 shows a schematic configuration of the motor-driven variable valve timing devices 270 and 370. Here, an outline of the variable valve timing devices 270 and 370 will be described with reference to FIG.

  As shown in FIG. 2, the valve timing variable devices 270 and 370 provided at one ends of the intake camshafts 260 and 360 in the first bank 200 and the second bank 300 are the crankshaft 120 and the intake camshaft. 260 and 360, which are provided in a rotation transmission path between them and are operated by electric motors 271 and 371 that rotate in synchronization with the crankshaft 120 and the intake camshafts 260 and 360. The variable valve timing devices 270 and 370 are provided with speed reduction mechanisms 272 and 372 and link mechanisms 273 and 373 that transmit the rotation of the crankshaft 120 to the intake camshafts 260 and 360. That is, the speed reduction mechanisms 272 and 372 and the link mechanisms 273 and 373 are provided in a rotation transmission path between the crankshaft 120 and the intake camshafts 260 and 360. The speed reduction mechanisms 272 and 372 are connected to the motors 271 and 371 and transmitted to the link mechanisms 273 and 373 in a state where the rotations of the motors 271 and 371 are decelerated by a plurality of gears 272a, 372a, 272b, and 372b. To do. In addition, the link mechanisms 273 and 373 are displaced by the crankshaft 120 by the displacement of the first to fourth links 273a to 273d and 373a to 373d according to the speed increase / decrease of the motors 271 and 371 transmitted from the speed reduction mechanisms 272 and 372. The relative rotational phase of the intake camshafts 260 and 360 is changed.

In these variable valve timing devices 270 and 370, the rotational speeds of the intake camshafts 260 and 360 are increased and decreased by increasing and decreasing the rotational speeds of the motors 271 and 371 that rotate in synchronization with the crankshaft 120 and the intake camshafts 260 and 360. Increases and decreases with respect to the rotation speed (reference speed) obtained by receiving the rotation transmission from the crankshaft 120. Here, the reference speed increases as the rotational speed of the crankshaft 120 increases, and conversely decreases as the rotational speed of the crankshaft 120 decreases. The relative rotational phase of the intake camshafts 260 and 360 with respect to the crankshaft 120 is made constant by adjusting the rotational speeds of the motors 271 and 371 so that the rotational speeds of the intake camshafts 260 and 360 coincide with the reference speed. Retained. On the other hand, when the rotational speeds of the motors 271 and 371 are increased so that the rotational speeds of the intake camshafts 260 and 360 are larger than the reference speed, the relative rotational speeds of the intake camshafts 260 and 360 with respect to the crankshaft 120 are increased. It is changed to the advance side. Further, when the rotational speed of the motors 271 and 371 is lowered so that the rotational speed of the intake camshafts 260 and 360 is smaller than the reference speed, the relative rotational phase of the intake camshafts 260 and 360 with respect to the crankshaft 120 is changed. It is changed to the retard side. The specific mechanism of such motor-driven variable valve timing devices 270 and 370 is described in detail in Japanese Patent Laid-Open No. 2007-255410 by the present applicant.

  On the other hand, as shown in FIG. 1, the rocker arms 362 and 382 provided in the second bank 300 are all provided with valve drive stop mechanisms 366 and 386 for stopping the drive of the engine valves. Yes. The valve drive stop mechanisms 366 and 386 will be described in detail below.

  In the internal combustion engine 10, the relative movement of the rollers 363 and 383 with respect to the rocker arms 362 and 382 is prohibited by the valve drive stop mechanisms 366 and 386 when the all cylinder operation is performed. For this reason, when the cam noses of the intake cam 361 and the exhaust cam 381 slide on the rollers 363 and 383, the intake valve 364 and the exhaust valve 384 are pushed down by the rocker arms 362 and 382 by the height of the cam nose. Then, the valve is opened.

  In the internal combustion engine 10, when the reduced cylinder operation is performed, relative movement of the rollers 363 and 383 with respect to the rocker arms 362 and 382 is permitted by the valve drive stop mechanism 366 and 386. At this time, whenever the cam noses of the intake cam 361 and the exhaust cam 381 slide on the rollers 363 and 383, the rollers 363 and 383 are pushed down toward the cylinders 211 and 311 by the height of the cam nose. The intake valve 364 and the exhaust valve 384 are kept closed.

  Although only one intake cam 361 and exhaust cam 381 are shown in FIG. 1, for example, the internal combustion engine 10 to be controlled in this embodiment has two intake valves and two exhaust valves per cylinder. If two V-type eight-cylinder internal combustion engines are provided, the second bank 300 is provided with a total of 16 engine valves. When the reduced cylinder operation is executed, all of these 16 engine valves are closed, and so-called one-bank operation is executed.

  As described above, when the reduced-cylinder operation is executed, all the engine valves included in the second bank 300 are closed so that all the cylinders of the second bank 300 are deactivated. The configuration of 366, 386 and the control mode of the valve drive stop mechanism 366, 386 can be further simplified.

  By the way, when the internal combustion engine 10 is operated, there are many driving mechanisms such as a drive system for the crankshaft 120, a drive system for engine valves, a speed reduction mechanism 272, 372 and a link mechanism 273, 373 constituting the valve timing variable devices 270, 370. The components slide on each other. Therefore, the internal combustion engine 10 is also provided with a lubrication system that supplies engine oil (lubricating oil) that functions as a working lubricant to these sliding portions.

FIG. 3 shows an outline of such a lubrication system, that is, an engine oil supply system.
As shown in FIG. 3, an oil pump 130 provided at one end of the crankshaft 120 and driven by the rotation of the crankshaft 120 is provided with an oil suction port and an oil discharge port. An oil strainer 14 that supplies the oil pump 130 with foreign oil from the engine oil stored in the oil pan 110 is removed from the oil suction port.
0 is provided, and an oil passage for supplying engine oil to the entire internal combustion engine 10 is connected to the oil discharge port via an oil filter that removes minute foreign matters that cannot be removed by the oil strainer 140. Yes.

  When the operation of the internal combustion engine 10 is started and the crankshaft 120 rotates, the oil pump 130 is driven to rotate, and the engine oil stored in the oil pan 110 is drawn into the oil pump 130 via the oil strainer 140. The engine oil sucked into the oil pump 130 is first supplied to the cylinder heads of the first bank 200 and the second bank 300 through the oil passage connected to the oil discharge port. After that, the oil is supplied to the intake camshafts 260 and 360 and the exhaust camshafts 280 and 380, the variable valve timing devices 270 and 370, and further to the cylinder blocks 210 and 310 via the cam journal. Thereafter, the crankshaft 120 is supplied via a crank journal. Such supply of engine oil maintains the lubrication of each part described above.

Next, an outline of the electrical configuration and functions of the control apparatus for an internal combustion engine according to the present embodiment will be described with reference to FIG.
As shown in FIG. 4 (or FIG. 1 above), this device includes an electronic control device 400.

  The electronic control unit 400 includes an arithmetic processing unit (CPU), a program memory (ROM), a data memory (RAM), and the like, and controls the valve timing variable devices 270 and 370 and the valve drive stop mechanisms 366 and 386. Including a microcomputer that executes various controls including an input unit that receives detection signals from various sensors that detect engine operating conditions, and a driver that drives the various actuators based on commands from the microcomputer Yes.

  Here, the air flow meter 420 connected to the input unit of the electronic control device 400 is provided upstream of the junction of the intake pipe 240 of the first bank 200 and the intake pipe 340 of the second bank 300, and these intake pipes. The crank angle sensor 430 is an angle sensor that outputs a signal corresponding to the rotation angle (rotation speed) of the crankshaft 120. Similarly, an oil temperature sensor 440 connected to the input unit of the electronic control device 400 is provided in the oil pan 110 and detects the temperature of engine oil (lubricating oil) stored in the oil pan 110. The battery current sensor 450 is a sensor that detects a current flowing into and out of the in-vehicle battery 410 in order to obtain an output voltage of the vehicle-mounted battery 410 each time.

  On the other hand, the above-described fuel injection valves 250 and 350 and spark plugs 251 and 351 provided in the first bank 200 and the second bank 300 are respectively connected to the output portion of the electronic control device 400 via corresponding drivers. It is connected. In addition to these, the electronic control device 400 includes electric motors 271 and 371 for driving the valve timing variable devices 270 and 370 included in the banks 200 and 300, and a valve drive stop mechanism provided in the second bank. 366 and 386 are also connected through corresponding drivers.

In the electronic control device 400 configured in this way, the intake air amount GA, the engine speed NE, the lubricating oil temperature OT, the battery voltage BV, and the like are calculated based on the output signals of the various sensors taken into the input unit. These calculated values are temporarily stored in an internal memory. Further, based on the calculated intake air amount GA and the engine speed NE, the engine load KL, the fuel injection period, the ignition timing, or the optimal opening / closing timing of the intake valves 264, 364, that is, the target phase of the camshaft, etc. Is calculated. The fuel injection valves 250 and 350 and the spark plug 25
For 1,351, the drive is controlled based on the calculated fuel injection period and ignition timing. For the target phase of the camshaft, the difference between the target phase and the current phase is calculated, and the driving (rotation) mode of the corresponding electric motors 271 and 371 is controlled so that this difference is absorbed. The calculated engine load KL, fuel injection period, ignition timing, etc. are also temporarily stored in the internal memory.

  On the other hand, in the electronic control device 400, in a certain operating region determined from the calculated engine load KL and the engine speed NE, a reduction in a part of the cylinders is stopped for the purpose of improving fuel consumption as an internal combustion engine. Perform cylinder operation. However, at the time of executing this reduced cylinder operation, if an inconvenience that hinders engine operation occurs in the operating cylinder, there is a high possibility that the internal combustion engine 10 will stall. Therefore, in the present embodiment, when the stable operation of the engine cannot be compensated depending on only the operating cylinder, the execution of the reduced cylinder operation is prohibited.

Details of the switching control executed in the control device of the present embodiment will be described below with reference to FIGS.
FIG. 5 is a flowchart showing a control procedure of operation switching control executed through the electronic control device 400. The processing related to this control is repeatedly executed every predetermined time.

  As shown in FIG. 5, in this control, first, the engine load KL, the engine speed NE, the lubricating oil temperature OT, and the battery voltage BV stored in the internal memory are read (step S700). Then, among these read values, whether or not the operating state of the internal combustion engine 10 is in the region where the reduced cylinder operation is executed is determined using the map shown in FIG. 6 from the engine load KL and the engine speed NE. Is determined (step S701). Here, the map shown in FIG. 6 is a map that is created in advance based on an experiment or the like and stored in a ROM or the like in the electronic control device 400. Based on this map, the engine operation region where both the engine load KL and the engine speed NE are relatively small is defined as the reduced cylinder operation region B, and the engine load KL and the engine speed NE are smaller than the reduced cylinder operation region B. A region where at least one of the two is larger is defined as an all-cylinder operation region A. That is, in step S701, it is determined whether the engine operating range determined by the engine load KL and the engine speed NE read in step S700 belongs to the reduced-cylinder operating range B or the all-cylinder operating range A. Is done.

  Here, when it is determined that the engine operation region is within the all-cylinder operation region A (step S701: NO), all-cylinder operation is executed (step S704). On the other hand, when it is determined in the process of step S701 that the engine operation region is in the reduced cylinder operation region B (step S701: YES), the read oil temperature OT is equal to or lower than the predetermined temperature α. Whether or not the battery voltage BV is equal to or lower than the predetermined voltage β is determined (step S702).

Here, the engine oil functioning as the lubricating oil for the valve timing variable devices 270, 370, etc., increases in viscosity as the temperature decreases, and as the viscosity of this lubricating oil increases, the valve oil as the valve timing variable devices 270, 370 increases. The operability is also reduced. Therefore, in the present embodiment, the predetermined temperature α is used as the lowest temperature at which the influence of the engine oil viscosity on the valve timing variable devices 270 and 370 can be ignored, that is, proper lubrication is maintained. The temperature is set to be possible. Further, since the valve timing variable devices 270 and 270 are driven by the electric motors 271 and 371, even if the output voltage of the battery 410 applied to the electric motors 271 and 371 decreases, the valve timing changes. The operability as the variable devices 270 and 370 is lowered. Therefore, in the present embodiment, even the predetermined voltage β can be maintained at the minimum voltage value that can ignore the influence on the operability of the valve timing variable devices 270 and 370, that is, proper power supply. The voltage value is set.

  If these two conditions are not satisfied as a result of the above determination (step S702: NO), the electronic control unit 400 is permitted to execute the reduced-cylinder operation because the valve timing variable devices 270 and 370 can operate normally. (Step S703). That is, all the engine valves provided in the second bank 300 are stopped by the valve drive stop mechanisms 366 and 386, and the fuel injection valves 350 of the second bank 300 are all driven into the intake pipe 340. Fuel injection is also stopped, and these cylinders are put into a resting state.

  On the other hand, if at least one of the above two conditions is satisfied (step S702: YES), the reduced-cylinder operation is prohibited and the all-cylinder operation is executed because the normal operation of the valve timing variable devices 270 and 370 is jeopardized. (Step S704).

  According to the operation switching control executed through the processing shown in FIG. 5, the engine operation state determined by the engine load KL and the engine speed NE is within the reduced cylinder operation region B defined by the map of FIG. Even if the engine oil temperature OT is equal to or lower than the predetermined temperature α, or the output voltage of the battery 410, that is, the battery is equal to or lower than the predetermined voltage β, the reduced-cylinder operation is prohibited. Become so. For this reason, even if the engine temperature is such that the oil temperature OT and the battery voltage BV affect the operability of the variable valve timing devices 270 and 370, more stable engine operation can be maintained.

As described above, according to the control apparatus for an internal combustion engine according to the present embodiment, the effects listed below can be obtained.
(1) When at least one of the two conditions that the oil temperature OT of the engine oil that is the working lubricant is equal to or lower than the predetermined temperature α or the battery voltage BV is equal to or lower than the predetermined voltage β is satisfied, Even if the engine operation region is in the reduced cylinder operation region, execution of the reduced cylinder operation is prohibited because the normal operation of the valve timing variable devices 270 and 370 is jeopardized. This makes it possible to suppress instability of engine operation caused by executing reduced-cylinder operation despite the fact that the operability of the valve timing variable devices 270 and 370 is not ensured. It becomes possible to maintain a stable engine state according to the state.

  (2) When the reduced-cylinder operation is executed, the valve drive stop mechanism 366, 386 stops the opening / closing drive of the engine valve of the idle cylinder. As a result, the pumping loss is reduced by the amount that intake and exhaust are not executed in the deactivated cylinder, and as a result, the fuel consumption of the entire internal combustion engine can be further improved.

(3) When the reduced-cylinder operation is carried out, all the cylinders located in the second bank 300 among the cylinder groups arranged in the V-type are brought into a resting state. As a result, the configuration of the valve drive stop mechanisms 366 and 386 that are driven when the reduced-cylinder operation is executed and the control mode of the valve drive stop mechanisms 366 and 386 can be simplified.
[Second Embodiment]
In the first embodiment, the reduced-cylinder operation is prohibited when the oil temperature OT is equal to or lower than the predetermined value α or the battery output voltage BV is equal to or lower than the predetermined value β. In the second embodiment, the reduced-cylinder operation is prohibited when at least one of the above two conditions is satisfied and the valve timing variable devices 270 and 370 are operating.

That is, in this case, instead of the operation switching control shown in FIG. 5 executed in the first embodiment, the operation switching control as exemplified in FIG. 7 is executed. However, step S900, step S901, step S90 of the operation switching control shown in FIG.
2 and the processing executed as step S904 are the same as the processing executed as steps S700 to S703 of FIG. 5, respectively, and the description thereof is omitted.

  In the second embodiment, when the operation switching control shown in FIG. 7 is performed, in the determination in step S902, the oil temperature OT of the engine oil is equal to or lower than the predetermined value α, or the battery voltage BV is equal to or lower than the predetermined value β. Is determined (step S902: YES), it is then determined whether or not the valve timing variable devices 270 and 370 are operating (step S903). Here, when there is a request for changing the opening / closing timing of the intake valves 264, 364 and the valve timing variable devices 270, 370 are operating (step S903: YES), the cylinder reduction is performed in order to suppress instability of the engine operation. The operation is prohibited and the all-cylinder operation is executed (step S906).

  On the other hand, for example, when the variable valve timing devices 270 and 370 are not operating due to idle driving or constant speed running of the vehicle by so-called cruise control (step S903: NO), the execution of reduced cylinder driving is permitted. (Step S905).

According to such a configuration as a control device for an internal combustion engine, in addition to the effects (1) to (3) according to the first embodiment, the following effects can be further obtained.
(4) Even if at least one of the conditions that the oil temperature OT is equal to or lower than the predetermined value α or the battery voltage BV is equal to or lower than the predetermined value β is satisfied, the valve timing variable devices 270 and 370 are not operated. If there is a low possibility that the engine operation will become unstable even if the reduced-cylinder operation is executed, the reduced-cylinder operation is not prohibited. As a result, it is possible to keep the engine operating state in which the reduced-cylinder operation is prohibited to a minimum range, and further improve the fuel consumption of the internal combustion engine as a whole.

In addition, each said embodiment can also be implemented with the following forms which changed this suitably.
The valve timing variable devices 270 and 370 are not limited to the configuration of the above embodiment as long as the opening / closing timing of the engine valve is variable based on the driving of the electric motors 271 and 371.

  The variable valve timing devices 270 and 370 are provided only on the intake camshafts 260 and 360 that define the opening and closing timings of the intake valves 264 and 364, but the exhaust camshafts 280 that define the opening and closing timings of the exhaust valves 284 and 384 are provided. 380 may be provided with the same valve timing varying device. Further, a variable valve timing device may be provided on both the intake camshafts 260, 360 and the exhaust camshafts 280, 380.

  The internal combustion engine controlled by the control device of the internal combustion engine is not limited to the valve timing variable devices 270 and 370 that change the opening / closing timing of the engine valve, but as a variable valve mechanism, the engine valve is based on the drive of an electric motor. It may be an internal combustion engine that employs a variable valve lift amount device that makes the lift amount variable.

  The internal combustion engine controlled by the control device for the internal combustion engine may include both a valve timing variable device and a valve lift amount variable device as a variable valve operating device. In this case, at least one of the variable valve timing device and the variable valve lift amount device only needs to change the valve characteristic of the engine valve based on the drive of the electric motor.

As the valve drive stop mechanisms 366 and 386, when stopping the driving of the engine valve and executing the reduced cylinder operation, the rollers that come into contact with the intake cam and the exhaust cam can be moved relative to the rocker arm. As a result, the cam and the engine valve are mechanically cut off, and the drive of the engine valve is stopped. The configuration is not limited to this, and any configuration may be used as long as the force that pushes down the engine valve by the cam is not transmitted to the engine valve.

  Although the valve drive stop mechanisms 366 and 386 are provided, the reduced-cylinder operation can be executed only by stopping the fuel injection by the fuel injection valve 350 without providing such a mechanism. Even with such a configuration, it is possible to obtain an effect similar to the effects (1) and (3).

  ・ In the case of an internal combustion engine having a variable valve lift amount device as a variable valve operating device, the drive is stopped by setting the lift amount of the engine valve to “0” without providing the valve drive stop mechanisms 366 and 386 in particular. The reduced-cylinder operation can be executed.

  The cylinder arrangement of the internal combustion engine is not limited to the V type as described above. A cylinder arranged in series or a horizontally opposed arrangement may be used. Further, the number of cylinders is arbitrary as long as it is a multi-cylinder internal combustion engine capable of reducing cylinder operation.

  -All cylinders in the second bank 300 are set to the resting state when the reduced cylinder operation is executed. Not limited to this, only a part of the cylinders of the second bank 300 may be put into a resting state, and the effect equivalent to the effects (1) and (2) can be obtained by such a configuration.

  The valve drive stop mechanisms 366 and 386 are provided only in the second bank 300, but may be provided in both the first bank 200 and the second bank 300. In this case, when the reduced-cylinder operation is executed, a part of the cylinders are brought into a resting state for each of the first bank 200 and the second bank 300.

The number of cylinders that are deactivated by the valve drive stop mechanisms 366 and 386 may be variable depending on the engine operation state.
Although the oil temperature sensor 440 is provided in the oil pan 110 and thereby the oil temperature OT, which is the temperature of the engine oil, is directly measured, the present invention is not limited to this, for example, from the engine cooling water temperature measured by the cooling water temperature sensor The oil temperature OT may be estimated.

  Although the battery current sensor 450 is provided to measure the output voltage BV of the battery 410, the voltage output from the battery 410 to the electronic control unit 400 can be monitored without providing such a sensor. Thus, the output voltage BV of the battery 410 may be measured.

  A so-called port injection type gasoline engine that injects fuel into the intake pipes 240 and 340 is adopted as an internal combustion engine controlled by the control device for the internal combustion engine, but a so-called direct injection type that directly injects fuel into the cylinders 211 and 311. The present invention can be similarly applied to a gasoline engine or a diesel engine.

1 is a schematic configuration diagram showing a schematic configuration of a V-type multi-cylinder internal combustion engine to which a first embodiment of an internal combustion engine control device according to the present invention is applied. 1 is a schematic side view showing a schematic configuration of a variable valve timing device employed in the internal combustion engine. The perspective view which shows the outline of a lubrication aspect about the lubrication system of the internal combustion engine. The block diagram which shows typically the electrical structure about the control apparatus of the internal combustion engine which concerns on the same embodiment. The flowchart which shows the control procedure about the operation switching control by the control apparatus of the internal combustion engine of the embodiment. The graph (map) which shows the setting aspect of the reduced cylinder operation prohibition area | region in the embodiment. The flowchart which shows the control procedure of the operation switching control about 2nd Embodiment of the control apparatus of the internal combustion engine which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 100 ... Crank case, 110 ... Oil pan, 120 ... Crankshaft, 130 ... Oil pump, 140 ... Oil strainer, 200 ... 1st bank, 210, 310 ... Cylinder block, 211, 311 ... Cylinder, 220 320, piston, 230, 330 ... connecting rod, 240, 340 ... intake pipe, 240a, 340a ... intake port, 241, 341 ... exhaust pipe, 241a, 341a ... exhaust port, 250, 350 ... fuel injection valve, 251, 351 ... Spark plug, 260, 360 ... Intake cam shaft, 261, 361 ... Intake cam, 262, 282, 362, 382 ... Rocker arm, 263, 283, 363, 383 ... Roller, 264, 364 ... Intake valve, 265 285, 365, 385 ... Valve spring 270, 370 ... Valve timing variable device, 271,371 ... Electric motor, 272,372 ... Deceleration mechanism, 273,373 ... Link mechanism, 280,380 ... Exhaust camshaft, 281,381 ... Exhaust cam, 284,384 ... exhaust valve, 300 ... second bank, 366,386 ... valve drive stop mechanism, 400 ... electronic control device, 410 ... battery, 420 ... air flow meter, 430 ... crank angle sensor, 440 ... oil temperature sensor, 450 ... battery current Sensor.

Claims (5)

Provided with a variable valve system that varies the valve characteristics of an engine valve based on driving of an electric motor by power supplied from an in-vehicle battery, and sets a part of a plurality of cylinders to a rest state when the internal combustion engine is in a predetermined operation region In a control device for an internal combustion engine that controls the engine state through the variable valve device in order to obtain valve characteristics in accordance with the respective operation state while performing reduced-cylinder operation,
The output voltage of the in-vehicle battery is equal to or lower than a predetermined voltage that affects the operation of the variable valve device, and the temperature of the lubricating oil serving as the operating lubricant of the variable valve device is the operation of the variable valve device. A control device for an internal combustion engine, wherein execution of the reduced-cylinder operation is prohibited on the condition that at least one of a temperature lower than a predetermined temperature affecting the temperature is satisfied. Provided with a variable valve system that varies the valve characteristics of an engine valve based on driving of an electric motor by power supplied from an in-vehicle battery, and sets a part of a plurality of cylinders to a rest state when the internal combustion engine is in a predetermined operation region In a control device for an internal combustion engine that controls the engine state through the variable valve device in order to obtain valve characteristics in accordance with the respective operation state while performing reduced-cylinder operation,
The output voltage of the in-vehicle battery is equal to or lower than a predetermined voltage that affects the operation of the variable valve device, and the temperature of the lubricating oil serving as the operating lubricant of the variable valve device is the operation of the variable valve device. An internal combustion engine characterized in that execution of the reduced-cylinder operation is prohibited on the condition that at least one of the predetermined temperature affecting the temperature is satisfied and the variable valve device is operating. Control device. The variable valve operating device is a valve timing variable device that can continuously change the opening / closing timing of the engine valve, and the engine stops the opening / closing drive of the engine valves of some cylinders that are in the inactive state. The control apparatus for an internal combustion engine according to claim 1, wherein the reduced-cylinder operation is executed using the valve drive stop mechanism. The said cylinder reduction | decrease operation is performed by making the said engine consist of a V-type multicylinder internal combustion engine which has a V-type cylinder arrangement | sequence, and making some of these cylinders into a dormant state. The control apparatus of the internal combustion engine described in 1. 5. The control device for an internal combustion engine according to claim 4, wherein when executing the reduced cylinder operation, all the cylinders located in one bank of the cylinder group arranged in the V shape are put into a resting state.

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