DE112010000766T5 - Operation control apparatus and operation control method for a multi-cylinder internal combustion engine - Google Patents

Abstract

When the cylinder shut-off operation execution condition of a multi-cylinder internal combustion engine is satisfied, the temperature of the first catalytic converter (82L) provided in the exhaust passage (81L) connected to the cylinders that are shut down during the cylinder shut-off operation is estimated and when they are When the temperature is lower than the predetermined required preheating temperature, a catalyst preheating operation by which the ignition timing of the cylinders is retarded and the temperature of the catalytic converter (82L) is increased is carried out. After the temperature of the catalytic converter (82L) is equal to or greater than the required preheating temperature, the cylinder shutdown operation is started.

Description

BACKGROUND OF THE INVENTION

TECHNICAL FIELD OF THE INVENTION

The invention relates to an operation control device and an operation control method for a multi-cylinder internal combustion engine and a multi-cylinder internal combustion engine, respectively. More particularly, the invention relates to the improvement for extending a continuation duration of a cylinder cutoff operation in a multi-cylinder internal combustion engine in which the cylinder cutoff operation by which some of the cylinders are disabled in response to a load of the engine can be performed ,

DESCRIPTION OF THE RELATED ART

A multi-cylinder engine in which a cylinder cut-off operation can be performed in which some of the cylinders are turned off and a fuel consumption amount is improved when no load is applied to the engine is disclosed in, for example, Published Japanese Patent Applications JP 2005-351134 A . JP 2001-227369 A and JP 2001-182601 A known.

For example, in a condition having an auxiliary output such as during idling operation of an engine, the load applied to each cylinder becomes small. As a result, the intake and exhaust leakages increase and the combustion efficiency may decrease. For this reason, a cylinder cut-off operation may be performed in which the fuel supply to some cylinders (for example, cylinder of a bank in a V-type engine) is stopped and these cylinders are brought to an idle state (turned off) in accordance with the in Operating or operating cylinder (cylinder of the other cylinder bank) applied load and the combustion efficiency can be increased. In this way, the fuel consumption ratio can be improved and the amount of fuel consumed can be reduced.

In the publication JP 2005-351134 A is disclosed an arrangement in which a transition from the aforementioned cylinder shut-off operation to the all-cylinder operation (operation in which fuel is supplied to all cylinders) is executed when the temperature of the catalyst used in the exhaust system with the is lower than the activation temperature, the ignition timing is retarded or retarded in the working cycle of this cylinder. In this way, the catalyst temperature is increased rapidly and the exhaust emission is improved.

In the publication JP 2001-227369 A there is disclosed an arrangement in which the cylinder cut-off operation is prohibited when the temperature of the catalyst provided in the cylinder-connected exhaust system is less than a predetermined temperature (a temperature at which the catalyst is genuinely in an active state ). In other words, the transition to the all-cylinder operation is performed with decreasing catalyst temperature, thereby preventing deterioration of exhaust emission caused by the temperature drop of the catalyst to a temperature level equal to or below the activation temperature during the restoration of the overall cylinder operation.

In the publication JP 2001-182601 A is disclosed an arrangement in which the ignition is delayed and the exhaust gas temperature is increased when the control is performed for rapidly warming up the catalyst, and at this time by stopping the fuel injection into a few cylinders, the cylinder cut-off operation is executed.

However, in one as in the pamphlets JP 2005-351134 A and JP 2001-227369 A discloses an engine in which the cylinder cut-off operation is performed when the engine is configured such that the catalyst from the exhaust system connected to a cylinder (shut-off cylinder) is in a shut-down state during the cylinder cut-off operation (this catalyst will be described below) as the "shut-down cylinder catalyst"), and the catalyst of the exhaust system connected to a cylinder (working cylinder) that continues to operate (this catalyst will be referred to as "working cylinder catalyst" hereinafter) are independent of each other, the following problem occurs.

Thus, when the cylinder cut-off operation execution condition is satisfied, for example, when the engine is in an idling state, the catalyst temperature falls within a short time after the skip-off operation is started to near the lower limit of the activation temperature even if the temperature of the skip-cylinder catalyst becomes equal to or greater than the lower limit of the activation temperature (eg 450 ° C) at which the catalyst temperature is not sufficiently high (at least 50 ° C higher than the lower limit of the activation temperature of the catalyst), and the cylinder operation must be restored.

Specifically, in an engine in which intake valves and exhaust valves of the deactivated cylinder are opened and closed during the cylinder deactivation operation in the same manner as during the cylinder operation, the air (air having approximately the same temperature as the outside air) flows to the deactivated cylinder during the cylinder deactivation operation. In this way, the decrease of the catalyst temperature per unit time is rapidly increased and the above problem is aggravated.

In such cases, the duration of the cylinder cut-off operation is greatly shortened, and merits of the engine system in which the cylinder cut-off operation can be performed are hard to be fully exploited. As a result, the fuel consumption ratio improving effect as well as the fuel consumption amount reducing effect may not be fully exhibited.

Likewise, this problem can be found in the publications JP 2005-351134 A . JP 2001-227369 A and JP 2001-182601 A described arrangements occur. In other words, when in the JP 2005-351134 A described arrangement increases the catalyst temperature by delaying the ignition timing after a switching from Zylinderabschaltbetrieb in the overall cylinder operation. However, with such a technology, the operating time of the cylinder cut-off operation can not be increased by extending the duration in which the temperature of the cut-off cylinder catalyst is maintained in the cylinder cut-off operation at the activation temperature.

When in the JP 2001-227369 A In the disclosed arrangement, the cylinder cut-off operation is prohibited when the catalyst temperature becomes lower than the predetermined temperature, and this technology also does not prolong the interval at which the temperature of the cut-off cylinder catalyst is kept at the activation temperature in the cylinder cut-off operation.

When in the JP 2001-182601 A In the disclosed arrangement of the exhaust system, all cylinders are connected to the same catalyst (hence it is not an arrangement in which the shut-off cylinder catalyst and the working cylinder catalyst are independent of each other).

SUMMARY OF THE INVENTION

The present invention relates to a multi-cylinder internal combustion engine in which the cylinder cutoff operation can be performed, and provides an operation control apparatus and method for a multi-cylinder internal combustion engine which can maintain a high temperature of the shutdown cylinder catalyst during the cylinder cutoff operation and ensure a long sustain duration of the cylinder cutoff operation.

The present invention is based on the problem-solving principle of carrying out a control by which the catalyst temperature of the exhaust system connected in advance with a cylinder in a shut-off state during shut-down operation (scheduled shutdown) is set high in advance, and then the cylinder shut-down operation In this way, the interval at which the catalyst temperature drops to near the lower limit of the activation temperature during the cylinder cutoff operation and the operation period of the cylinder cutoff operation can be prolonged.

The first aspect of the invention relates to an operation control apparatus for a multi-cylinder internal combustion engine provided with a first catalyst provided in a first exhaust passage connected to at least one of a plurality of cylinders and a second catalyst provided in a second exhaust passage connected to the other cylinders wherein a cylinder cutoff operation that shuts off the at least one cylinder is executed in compliance with the satisfaction of a predetermined cylinder cutoff operation execution condition. The operation control device for a multi-cylinder internal combustion engine includes a catalyst temperature detecting device and a catalyst preheating operation executing device. The catalyst temperature detecting means detects a temperature of the first catalyst. The catalyst preheating operation execution means carries out a catalyst preheating operation for raising a temperature of the first catalyst to a temperature greater than or equal to a preheating temperature required before the skip-off operation is executed in the event that the temperature detected or estimated by the catalyst temperature-detecting means of the first catalyst is less than the predetermined required preheat temperature when the cylinder deactivation operation execution condition is satisfied.

The term "at least one cylinder turned off during the cylinder cutoff operation" means not only one cylinder but also a plurality of cylinders (for example, the cylinders of a cylinder bank of a V-type engine). Furthermore, can not only two catalysts or types of catalyst, ie, the first and the second catalyst, but also three or more catalysts independently be mounted as catalysts, which are mounted by their attachment in mutually different exhaust ducts independently.

According to the specific features described above, the temperature of the first catalyst is detected or estimated by the catalyst temperature detecting means when the cylinder deactivation operation execution condition is satisfied in executing the all-cylinder operation. When the temperature of the first catalyst is lower than the predetermined required preheat temperature, first, a catalyst preheat operation is performed to raise the temperature of the first catalyst to a temperature equal to or higher than the preheat temperature required, rather than immediately after the cylinder deactivation operation. Execution condition is met, to start the cylinder deactivation operation. After the temperature of the first catalyst is sufficiently increased to a temperature equal to or higher than the required preheating temperature by the execution of the catalyst preheating operation, the skip-off operation is started. In other words, because the cylinder cut-off operation is started in a state of a comparatively high temperature of the first catalyst, even if the temperature of the first catalyst gradually decreases during the cylinder cut-off operation, the required duration of dropping of this temperature to a temperature at which the recovery of the total cylinder operation is necessary (for example, the lower limit of the activation energy) to be extended. In this way, the operation period of the cylinder cut-off operation can be prolonged. Advantages of the engine system where the cylinder cut-off operation can be performed can be fully utilized, and the fuel consumption ratio improving effect as well as the fuel consumption amount reducing effect can be fully exhibited.

The catalyst preheating operation executing means may be configured to perform the catalyst preheating operation by spark retarding of a spark plug of the at least one cylinder which is put out of operation during the skip-off operation, or the catalyst preheating operation by non-sparking of the spark plug prior to the execution of the skip-off operation.

When the catalyst preheating operation advancing the ignition timing of the spark plug is performed late, the combustion start timing in the combustion process of the above-mentioned at least one cylinder (a cylinder that is turned off when a transition to the cylinder deactivation operation is executed) is also retarded, the combustion slowed down in these cylinders and assumed a state in which a part of the air-fuel mixture burns in the exhaust passage (first exhaust passage). In this way, by significantly increasing the gas temperature within the exhaust system, the temperature of the first catalyst can be increased rapidly. As a result, the temperature of the first catalyst can be raised sufficiently and within a short time to a temperature equal to or higher than the required preheating temperature, and the fuel supplied during the operation period of the catalyst preheating operation can be effectively made to participate in the temperature increase of the first catalyst , In this way, the amount of fuel used for the catalyst preheating operation can be kept relatively low, and a significant increase in the fuel consumption amount can be prevented.

When the catalyst preheating operation is performed by non-ignition of the spark plug, almost all the air-fuel mixture contained by the cylinder enters the exhaust passage (first exhaust passage) as an unburned gas, the thermal energy of the first catalyst is absorbed, and the mixture is burned (oxidation reaction). In this case, the temperature of the first catalyst may also be significantly increased within a short time to a temperature equal to or higher than the required preheating temperature. Further, in this case, almost the entire amount of fuel supplied during the operation period of the catalyst preheating operation may be made to be involved in the temperature increase of the first catalyst. In this way, the amount of fuel used for the catalyst preheat operation can be reduced to a minimum amount. Thus, a certain thermal energy must be present within the first catalyst when the catalyst preheat operation is performed by non-ignition of the spark plug. Thus, this operation may be performed after the temperature of the first catalytic converter has been detected and the presence of sufficient thermal energy for combusting the air-fuel mixture within the first catalytic converter has been confirmed.

Further, the catalyst preheating operation may, prior to the execution of the skip-off operation, retard spark timing of the spark plugs of the cylinders disabled during the skip-off operation and gradually increase the lag amount of the spark timing, thereby reducing the energy produced by combustion of an air-fuel mixture to one Torque generation in the internal combustion engine gradually reduces the amount of kinetic energy and the amount of thermal energy participating in the catalyst preheating is gradually increased.

With such an arrangement in which the cylinder deactivation operation execution condition is satisfied and the catalyst preheat operation is started, the retard amount of the ignition timing of the spark plug is comparatively small during the start-up period and a majority of the generation of the air-fuel mixture Energy becomes kinetic energy involved in torque generation in the internal combustion engine, with some of the energy being used as thermal energy involved in the catalyst preheating (heating or warming up of the first catalyst). Then, as the spark timing of the spark plugs increases late, the amount of kinetic energy participating in the generation of torque in the internal combustion engine from the energy generated by the combustion of the air-fuel mixture gradually decreases as the amount of thermal energy involved in the catalyst preheating gradually increases. When the temperature of the first catalyst becomes equal to or higher than the required preheat temperature, the catalyst preheating operation is stopped and the skip-off operation is started. Consequently, during the catalyst preheating operation, when a switching operation from the all cylinder operation to the cylinder deactivation operation is performed, the engine torque gradually decreases. As a result, sudden torque fluctuations during such an operation mode switching operation are prevented and the occurrence of vibration (shocks) during the operation mode switching operation is almost eliminated. In other words, a switching operation from the overall cylinder operation to the cylinder shut-off operation may be performed so that the vehicle occupants are unaware of the operation mode switching operation and driveability can be significantly improved. Thus, with the present problem solving means, a new switching operation from the all-cylinder operation to the cylinder deactivation operation causing almost no vibration during the operation switching operation can be realized, and the fuel consumption ratio improving effect and the fuel consumption amount reducing effect can be achieved by extending the operation period of the cylinder cut-off operation.

Further, the catalyst preheating operation executing means may also retard a fuel supply timing of the at least one cylinder, which is put out of operation during the skip-off operation, before executing the skip-off operation.

In this case, the air-fuel mixture is also burned in the first exhaust passage or the first catalyst. Thus, the temperature of the first catalyst can be increased within a short time at a temperature equal to or higher than the required preheating temperature.

During the cylinder deactivation operation, when the temperature of the first catalyst has dropped to a predetermined total cylinder operation recovery temperature, a shift from cylinder deactivation operation to overall cylinder operation may be performed. Further, the total cylinder operation recovery temperature may be set to a temperature higher than a lower limit of the activation temperature of the first catalyst at which the air-fuel mixture inside the first catalytic converter may be combusted, and to a temperature lower than the required preheat temperature (Lower limit of the activation temperature of the first catalyst) <(total cylinder operation recovery temperature) <(required preheat temperature).

When the temperatures are so selected (the required preheat temperature is higher than the total cylinder operation recovery temperature and the total cylinder operation recovery temperature is set higher than the lower limit of the activation temperature of the first catalyst), both the time that falls during the cylinder deactivation operation to decrease the temperature in the Near the lower limit of the activation energy is required, as well as the deterioration of the exhaust emission can be prevented, in which a switching operation is performed by the cylinder deactivation operation in the overall cylinder operation.

The second aspect of the invention relates to an operation control method for a multicylinder internal combustion engine provided with the first catalyst provided in a first exhaust passage connected to at least one of a plurality of cylinders and a second catalyst provided in a second exhaust passage connected to the other cylinders the Zylinderabschaltbetrieb that shuts off the at least one cylinder can be performed. The operation control method includes determining whether the predetermined cylinder deactivation operation execution condition is satisfied; detecting a temperature of the first catalyst; and performing a catalyst preheat operation to raise a temperature of the first catalyst to a temperature greater than or equal to one required preheating temperature before the Zylinderabschaltbetrieb is executed, when the detected or estimated temperature of the first catalyst is less than the predetermined required preheating temperature when the Zylinderabschaltbetrieb execution condition is met.

According to the second aspect of the invention, the operation period of the cylinder cut-off operation can be extended, advantages of the engine system in which the cylinder cut-off operation can be performed can be fully utilized, and the fuel consumption ratio improving effect as well as the fuel consumption amount reducing effect can be fully exhibited.

When the cylinder cut-off operation is started, according to the invention, the control by which the catalyst temperature from the exhaust system connected to the cylinder cut-off during the cylinder cut-off operation is set in advance is executed, and then the cylinder cut-off operation is started. In this way, the duration required for the catalyst temperature to drop to near the lower limit of the activation temperature during the cylinder deactivation operation may be increased. In this way, the operation period of the cylinder cut-off operation can be prolonged, and the fuel consumption ratio improving effect as well as the fuel consumption amount reducing effect can be fully exhibited.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the invention will be apparent from the following description of exemplary embodiments with reference to the accompanying drawings, in which like reference numerals are used to denote like elements. Show it:

1 a schematic arrangement of an internal structure of a V-engine of the present invention with a view along a central axis of a crankshaft;

2 an illustration of a system arrangement schematically showing the engine, an intake exhaust system and a control system;

3 a block diagram showing the control system of the engine; and

4 a flowchart showing an operation of an operation switching operation control.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

An embodiment of the invention will be described below with reference to the attached drawings. In the present embodiment, a case will be described in which the invention is applied to a vehicle in which a six-cylinder V-type engine is installed as a gasoline engine.

Before describing the control executed during the switching operation in the cylinder switching operation, which is a specific feature of the invention, the general arrangement of the engine and a control block will be explained.

1 shows a schematic arrangement of an internal structure of a V-engine E of the present invention with a view along the central axis of a crankshaft C. 2 FIG. 12 is an illustration of a system arrangement schematically showing the engine E, an intake exhaust system, and a control system.

As shown in these figures, the V-type engine E has a pair of banks 2L . 2R , which is V-shaped in an upper portion of a cylinder block 1 protrude into it. The banks 2L . 2R are each in the upper end portion of the cylinder block 1 arranged cylinder heads 3L . 3R and with the cylinder head cover attached to the upper ends of the cylinder heads 4L . 4R Mistake. A variety of cylinders 5L . 5R (For example, three cylinders in each of the banks 2L . 2R ) is in the cylinder block 1 installed at a predetermined installation angle (for example 90 °), and pistons 51L . 51R are so inside the cylinder 5L . 5R assumed that the cylinders can move back and forth in it. The pistons 51L . 51R are via connecting rods 52L . 52R connected to the crankshaft C such that a force can be transmitted to them. Further, a crankcase 6 under the cylinder block 1 mounted and a space from the lower section inside the cylinder block 1 to the interior of the crankcase 6 serves as a crank chamber 61 , An oil pan serving as an oil reservoir 62 is also under the crankcase 6 intended.

Intake valves or intake valves 32L . 32R for opening and closing inlet openings 31L . 31R and exhaust valves 34L . 34R for opening and closing outlet openings 33L . 33R are each in the cylinder heads 3L . 3R installed, and the opening process and the closing operation of the valves 32L . 32R . 34L and 34R is due to the rotation of camshafts 35L . 35R . 36L and 36R in between the cylinder heads 3L . 3R and the Cylinder head covers 4L . 4R trained cam chambers 41L . 41R are arranged, executed.

The cylinder heads 3L . 3R of the motor E of the present embodiment have a divided structure. In particular, the cylinder heads 3L . 3R each through one on top of the cylinder block 1 mounted cylinder head main body 37L . 37R and one at the top of the cylinder head main body 37L . 37R attached camshaft housing 38L . 38R educated.

intake manifold 7L . 7R which the benches 2L . 2R are in the upper section on the inside of the benches 2L . 2R (Side between the benches) arranged and the downstream ends of the intake manifold 7L . 7R are with the inlet openings 31L . 31R connected. Further, the intake manifolds 7L . 7R with a pressure equalization tank 71 (please refer 2 ) connected to which the banks and one with a throttle valve or a throttle valve 72 provided inlet pipe 73 share. An air filter 74 is on an upstream side of the inlet pipe 73 intended. In this way, that of the air filter 74 in the intake pipe 73 introduced air via the surge tank 71 in the intake manifold 7L . 7R initiated.

injectors 75L . 75R are each in the inlet openings 31L . 31R the cylinder heads 3L . 3R provided, and when fuel from the injectors 75L . 75R is injected or injected, then an air-fuel mixture is obtained in which the intake manifold 7L . 7R introduced air with that of the injectors 75L . 75R injected fuel is mixed, and once the intake valves 32L . 32R are open, the air-fuel mixture is in a combustion chamber 76L . 76R initiated.

spark 77L . 77R are in the upper sections of the combustion chambers 76L . 76R arranged. In the combustion chambers 76L . 76R which is due to the ignition of the spark plugs 77L . 77R produced combustion pressure of the air-fuel mixture on the piston 51L . 51R transferred, causing a reciprocating motion of the piston 51L . 51R is caused. The reciprocation of the pistons 51L . 51R gets over the tie rods 52L . 52R transferred to the crankshaft C, converted into a rotational movement and output as an output of the engine E. The camshafts 35L . 35R . 36L and 36R are rotationally driven by the output from the crankshaft C and transmitted via a timing chain power, and this rotation opens or closes the valves 32L . 32R . 34L and 34R ,

The air-fuel mixture, after combustion, becomes an exhaust gas that enters the exhaust manifold 8L . 8R is released when the exhaust valves 34L . 34R be opened. exhaust pipes 81L . 81R are with the exhaust manifolds 8L . 8R connected and catalytic converters 82L . 82R , each containing a three-way catalyst are to the exhaust pipes 81L . 81R attached. If the exhaust gas is the catalytic converter 82L . 82R flows through, then in the exhaust gas contained hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxide components (NOx) are cleaned. Further, the downstream ends of the exhaust pipes run 81L . 81R together and are with a damper 83 connected.

The operating state of the above-described engine E is controlled by an electronic control unit (ECU). 9 controlled by the engine. As in 3 shown is the engine-ECU 9 with a central processing unit (CPU) 91 , a read-only memory (ROM) 92 , a random access memory (RAM) 93 and a backup RAM 94 Mistake. The ROM 92 stores control programs and maps that are accessed when the control programs are executed. The CPU 91 performs calculations based on the in the ROM 92 stored control programs and maps.

The RAM 93 is a memory that is temporarily in the CPU 91 obtained calculation programs and data entered by sensors stores. The backup RAM 94 is a non-volatile memory that stores data to be stored when the engine E is stopped. The ROM 92 , RAM 93 , Backup RAM 94 and the CPU 91 are via a bus with each other as well as with an external input circuit 95 and an external output circuit 96 connected.

A water temperature sensor 101 , an air mass meter 102 , an intake temperature sensor 103 , an A / F sensor 104a , an O ₂ sensor 104b , a throttle position sensor 105 , a crankshaft angle sensor 106 , a camshaft angle sensor 107 , a knock sensor 108 , a suction pressure sensor 109 and an accelerator depression amount sensor and accelerator depression amount sensor, respectively 110 are with the external input circuit 95 connected. The injectors 75L . 75R , an ignition device 111 and a throttle motor 72a which the throttle 72 drives are with external input circuit 96 connected.

The water temperature sensor 101 detects the temperature of the cooling water inside a water jacket 11 in the cylinder block 1 is formed, flows and sends a cooling water temperature signal to the engine-ECU 9 ,

The air mass meter 102 detects the intake air amount and sends an intake air quantity signal to the engine ECU 9 ,

The intake air temperature sensor 103 is on a downstream side of the air filter 74 provided, detects an intake air temperature and sends an intake air temperature signal to the engine-ECU 9 ,

The A / F sensor 104a is on an upstream side of the catalytic converter 82L . 82R intended. For example, an oxygen concentration sensor of a limited power system can be used for this purpose. The A / F sensor 104a generates an output voltage corresponding to an air-fuel ratio over a wide air-fuel ratio range and sends a voltage signal to the engine ECU 9 ,

The O ₂ sensor 104b is on a downstream side of the catalytic converter 82L . 82R intended. For example, an oxygen concentration sensor 104b an electromotive force system or drive system (density-battery system or density-field-line system or "density battery system") are used.

The O ₂ sensor 104b determines whether the air-fuel ratio in the exhaust gas is a stoichiometric air-fuel ratio and sends a detection signal to the engine ECU 9 ,

The throttle position sensor 105 detects an opening degree of the throttle valve 72 and sends a throttle opening degree detection signal to the engine ECU 9 ,

The crankshaft angle sensor 106 is disposed in the vicinity of the crankshaft C and detects a rotation angle (crank angle CA) of the crankshaft C and a rotation speed (engine rotation speed NE). In particular, there is the crankshaft angle sensor 106 a pulse signal for each predetermined crank angle (for example, 30 °). An example of a method for detecting the crank angle with the crankshaft angle sensor 106 is described below. Thus, an external tooth for each 30 ° on an outer peripheral surface of a non-rotatable with the crankshaft C rotor 106a (NE rotor), and the crankshaft angle sensor formed by an electromagnetic encoder 106 is located opposite the external tooth. When the outer number due to the rotation of the crankshaft C, the vicinity of the crankshaft angle sensor 106 passes through, generates the crankshaft angle sensor 106 an output pulse. In some cases, it becomes a NE rotor 106a used in which on the outer peripheral surface of the external tooth is formed every 10 °. In this case, an output pulse signal of every 30 ° crank angle by frequency division in the engine ECU 9 generated.

The camshaft angle sensor 107 is near the intake camshafts 35L . 35R and is used as a cylinder determination sensor by outputting a pulse signal corresponding to a top dead center (TDC) of, for example, the first cylinder. In other words, the camshaft angle sensor gives 107 for each revolution of the intake camshafts 35L . 35R a pulse signal. An example method for detecting the camshaft angle with the camshaft angle sensor 107 will be described below. Thus, on the outer peripheral surface, one with the intake camshaft 35L . 35R rotatable rotor formed an external tooth and formed by an electromagnetic encoder camshaft angle sensor 107 is located opposite the external tooth. If the external tooth due to the rotation of the intake camshaft 35L . 35R the proximity of the camshaft angle sensor 107 passes through, generates the camshaft angle sensor 107 an output pulse signal. The above rotor rotates at half crankshaft speed C. Thus, the crankshaft C generates an output pulse every time it rotates 720 °. In other words, an arrangement is provided in which an output pulse is generated every time a particular cylinder executes the same clock (for example, when the first cylinder is in the compression top dead center).

The knock sensor 108 is for every bank 2L . 2R intended. This is a vibration sensor that goes to the cylinder block 1 transmitted motor vibrations with a piezoelectric system (piezoelectric element) or an electromagnetic system (a magnet and a coil) detected. An output signal corresponding to the amplitude of the vibrations of the cylinder block 1 will be sent to the engine ECU 9 Posted.

The suction pressure sensor 109 is to the surge tank 71 mounted, detects a pressure within the intake pipe 73 (Intake manifold internal pressure) and sends an intake pressure signal to the engine-ECU 9 ,

The accelerator depression amount sensor 110 outputs a detection signal corresponding to the depression amount of the accelerator pedal (accelerator depression amount). The operating speed of the accelerator pedal may be detected by detecting the variation amount of the accelerator depression amount per unit time.

The engine-ECU 9 then performs on the basis of output signals from the sensors 101 to 110 different types of control of the engine E including the Zündzeitpunktsteuerung by controlling different units, such as the ignition device 111 , the injector 75L . 75R and the throttle motor 72a out.

If, for example, by the knock sensors 108 . 108 is detected during the execution of the pre-correction of the ignition timing to bring the ignition point close to the point of minimum best-torque (MBT) spark advance, then a control for executing a retard correction of the ignition timing and eliminating the knock as the basic control of the ignition timing becomes the spark plugs 77L . 77R what happened by the detonators 111 . 111 is determined, carried out.

Further, for the control of the injectors 75L . 75R calculate the target air-fuel ratio based on an engine load or engine speed and a control of a fuel injection amount (control of an opening time of the injectors 75L . 75R ) is performed to determine the desired air-fuel ratio based on the air mass meter 102 to receive detected intake air quantity. In this case, the amount of oxygen in the exhaust gas is based on the outputs of the A / F sensor 104a and the O ₂ sensor 104b calculated and a regulation of the air-fuel ratio through which the through the injectors 75L . 75R controlling certain amount of fuel injection is performed so as to guide the actual air-fuel ratio obtained from the calculated oxygen concentration to the target air-fuel ratio (eg, stoichiometric air-fuel ratio).

As the drive control of the throttle motor 72a becomes the driving amount of the throttle motor 72a controlled to an opening degree of the throttle 72 which ensures an intake air amount necessary for obtaining the required engine output, the control being performed based on the amount of depression of the driver-operated accelerator pedal.

The engine-ECU 9 also executes the cylinder cutoff operation control described below. The cylinder deactivation operation will be described below.

In the V-engine E of the present embodiment, the cylinder cut-off operation may be performed to control the operation of a group of cylinders (three cylinders in the present embodiment) connected to a bank (for example, the left bank 2L ) from the left bank 2L and the right bank 2R to stop. In other words, in a state with an extra power, for example, during the idling operation of the engine E, the load acting on the single cylinder is small. Consequently, the suction discharge load increases, and combustion efficiency deteriorates. For this reason, in a no-load condition or a low-load condition, the cylinder cut-off operation is performed by which the fuel supply to the cylinders of a bank is cut off and these cylinders are put out of operation. In this way, a load on the in-service cylinders (cylinders of the other bank) to which fuel is supplied is increased, and the operating efficiency increases, thereby improving the fuel consumption ratio.

As a concrete example of the cylinder deactivation operation, based on the engine speed based on the output of the crankshaft angle sensor 106 calculated by the throttle position sensor 105 detected opening degree of the throttle valve 72 determines whether the engine E is in a no-load condition and when the engine E is in a no-load condition, it is determined that the cylinder-shutdown operation execution condition is satisfied.

In the present embodiment, when the cylinder cut-off operation is performed, it is always the three cylinders of the left bank 2L which are turned off. The reason for this can be explained as follows. Because an arrangement is used in which the vaporized fuel produced in a fuel tank into the intake manifold 7R the right bank 2R (not shown in the drawings) and this vaporized fuel must be handled or used, thus become the three cylinders of the right bank 2R maintained in the operating state.

Such a cylinder cutoff operation mode is not limitative, and it is also possible that a bank that was in operation in the previous cylinder cutoff operation is turned off while the bank that was off in the previous cylinder cutoff operation is put into operation when transitioning to the cylinder cutoff operation. In other words, every time the cylinder deactivation operation starts, the power-down bank is alternately swapped, ensuring an equal distribution of the accumulated operating time between the cylinders and extending the life of the engine E.

In the present embodiment, the terms of the intake valve 32L and the exhaust valve 34L performed opening and closing operation of the deactivated cylinder during the Zylinderabschaltbetriebs similar to the processes that are carried out during the entire cylinder operation. In this way, the engine E of the present embodiment can be constructed without the conventional engine in which the Zylinderabschaltbetrieb not is executed, must undergo significant design changes.

In cylinder deactivation operation, the intake valve 32L and the exhaust valve 34L of the deactivated cylinder are completely closed. In this case, a by the reciprocating motion of the piston 51L Reduced pumping loss in the deactivated cylinder and the efficiency of the engine E can be increased.

An operation control, which is an essential feature of the present embodiment, in which the operation is switched between the all cylinder operation and the cylinder deactivation operation will be described below.

Thus, when the above-mentioned cylinder cut-off operation execution condition is satisfied, a temperature of the catalytic converter 82L in the exhaust pipe 81L (Exhaust pipe includes the first exhaust duct) is provided with the three cylinders of the left bank 21 that is, the connected cylinders, is estimated, and when the temperature is lower than a predetermined required preheat temperature, the catalyst preheat operation is performed before the execution of the cylinder deactivation operation to the temperature of the catalytic converter 82L (the catalyst preheat operation is performed by the catalyst preheat operation execution means).

In the following explanation, the catalytic converter becomes 82L in the exhaust pipe 81L is provided, with the three cylinders of the left bank 2L connected during the cylinder cutoff operation, a "first catalytic converter" (a first catalyst) 82L called, and the catalytic converter 82R in the exhaust pipe (exhaust pipe includes the second exhaust passage) 81R provided with the three cylinders of the right bank 2R which remain connected even during the cylinder cut-off operation, becomes a "second catalytic converter 82R Called "(a second catalyst).

4 FIG. 12 is a flowchart showing an operation of an operation switching operation control by which the operation is switched between the all-cylinder operation and the cylinder shut-off operation. In the 4 The routine shown is executed at a predetermined period or every predetermined rotational angle of the crankshaft C.

First, in step ST1, it is determined whether the cylinder cut-off operation execution condition is satisfied. As mentioned above, examples of the cylinder cut-off operation execution condition include whether the engine E is in a no-load condition such as an idling operation, and also whether by the water temperature sensor 101 detected temperature of the cooling water is equal to the predetermined temperature (for example, 50 °) or greater than this. In the present embodiment, the temperature condition of the first catalytic converter is 82L is not included in the cylinder cut-off operation execution condition determined in this step ST1. In other words, regardless of the temperature of the first catalytic converter 82L YES in step ST1, if the other shut-off operation execution condition is satisfied.

If the cylinder cut-off operation execution condition is not satisfied, NO is determined in step ST1, the processing flow goes to step ST7, and the overall cylinder operation is continued. Further, the total cylinder operation is restored when NO is determined during the cylinder cut operation execution in step ST1.

If the cylinder cut-off operation execution condition is satisfied, YES is determined in step ST1, and the processing flow goes to step ST2. In step ST2, it is determined whether the current operating state of the engine E is the total cylinder operating state. In other words, it is determined whether a state in which the cylinder deactivation operation execution condition is satisfied has been assumed from the state in which the all cylinder operation is performed because the cylinder deactivation operation execution condition therefor was not satisfied, or it is determined whether in the course of performing the catalyst preheat operation described below has not been transitioned to the cylinder cutoff operation and the overall cylinder operation is being performed.

When the engine E is in the all cylinder operating mode and YES is determined in step ST2, the processing flow goes to step ST3 and it is determined whether the temperature of the first catalytic converter 82L is less than the predetermined required preheat temperature (T1). In other words, it is determined whether the temperature of the first catalytic converter 82L falls within a very short time in the vicinity of the lower limit of the activation temperature and a quick changeover to the cylinder operating mode is required when going directly into the cylinder deactivation operation.

As the required preheating temperature (T1) is set a temperature which is about 150 ° higher than the lower limit of the activation temperature (for example, 450 °) of the first catalytic converter 82L is. However, these values are not limiting.

The temperature of the first catalytic converter 82L is estimated based on the current engine operating condition. In particular, a catalyst temperature estimation map is for estimating the temperature of the first catalytic converter 82L depending on the engine speed and the engine load (throttle opening degree and the like) in the ROM 92 stored and the temperature of the first catalytic converter 82 is estimated by substituting the current engine speed and the engine load in the catalyst temperature estimating map (catalyst temperature estimating operation is performed with the catalyst temperature detecting device). Furthermore, the temperature of the first catalytic converter 82L also be estimated by the exhaust gas temperature. For example, exhaust temperature sensors may be located on the upstream and downstream sides of the first catalytic converter 82L be provided and the temperature of the first catalytic converter 82L can be estimated based on the temperature detected by these exhaust gas temperature sensors. The temperature of the first catalytic converter 82L may also be directly detected by using a suitable means such as a thermistor (detection operation of the catalyst temperature made by the catalyst temperature detecting means).

When the temperature of the first catalytic converter 82L is equal to or greater than the required preheating temperature (NO is determined in step ST3), the processing flow goes to step ST6, and the skip-off operation, assuming that sufficient time can be ensured, until the temperature of the first catalytic converter 82L drops to the vicinity of the lower limit of the activation temperature, although it has proceeded directly to the cylinder deactivation operation. In other words, fuel injection into the cylinders of the left bank 2L stopped and the cylinders are switched off.

When the temperature of the first catalytic converter 82L is less than the required preheating temperature and YES is determined in step St3, the processing flow goes to step ST4, and the catalyst preheating operation is executed. Catalyst preheat operation involves retarding the spark timing in the left bank cylinders 2L provided spark plugs 77L in a state in which the all-cylinder operation is continued, that is, the fuel injection into these cylinders is continued.

In particular, the delay amount of the ignition timing is gradually increased. For example, the ignition timing is retarded every 10 revolutions of the crankshaft C by 1 ° CA (1 ° crank angle). However, this value is not limitative and can be determined in advance by a test or a simulation.

In this way, the combustion start timing in the combustion process of these cylinders (cylinders that are put out of action when going to the cylinder cutoff operation: cylinders to be deactivated) is also delayed, the combustion slowed down, and a state assumed that part of the air-fuel mixture in the exhaust pipe 81L is burned. Consequently, by greatly increasing the gas temperature in the first catalytic converter 82L provided exhaust system, the temperature of the first catalytic converter 82L be increased quickly.

Further, when the delay amount of the ignition timing is gradually increased, of the energy generated in the cylinders by combustion of an air-fuel mixture, the amount of kinetic energy involved in torque generation in the engine E is gradually reduced, and that of catalyst preheating of the first catalytic converter 82L The amount of thermal energy involved is gradually increased. In other words, when the cylinder deactivation operation execution condition is satisfied and the catalyst preheat operation is started, in the initial phase thereof, the retard amount of the ignition timing of the spark plug is 77L comparatively small and a major portion of an energy produced by the combustion of the air-fuel mixture becomes the kinetic energy involved in torque generation in the engine E, with some of the energy being thermal energy for preheating the first catalytic converter 82L is used. Then, as the delay amount of the ignition timing of the spark plug increases, it increases 77L the amount of kinetic energy involved in torque generation in the internal combustion engine E gradually decreases from the energy produced by combustion of an air-fuel mixture, while the amount of one at the preheating of the first catalytic converter 82L involved thermal energy gradually increases. Thus, in the catalyst preheat operation, the torque of the engine E gradually decreases while the preheat capacity of the first catalytic converter 82L gradually increases.

In this case, the maximum retard amount of the ignition timing is set so that the lower limit value of the torque of the engine E, which is varied to gradually decrease (the lower limit of the torque of the engine E during the catalyst preheat operation), is almost the torque of the engine E during the transition described below from the total cylinder operation to the cylinder shut-off operation (torque of the engine E in a case where only three cylinders operate in a no-load or low-load state).

As long as a catalyst preheat operation is performed and the cylinder cutoff operation execution condition is satisfied, the processes of steps ST1 to ST4 are repeated. When the cylinder deactivation operation execution condition is satisfied, the temperature of the first catalytic converter is satisfied 82L becomes equal to or greater than the required preheating temperature, NO is determined in step ST3, and the processing flow goes to step ST6. In step ST6, the catalyst preheating operation is stopped and the skip-off operation is executed when the temperature of the first catalytic converter 82L equal to or greater than the required preheat temperature.

In the above case, the torque of the engine E gradually decreases during the catalyst preheating operation. As a result, sudden torque fluctuations during the operation mode shift from the full cylinder operation mode to the cylinder deactivation operation mode are prevented, and the occurrence of vibration (shocks) during the operation mode shift operation is almost eliminated. In other words, a shift operation from the all-cylinder operation to the cylinder shut-down operation can be performed so that the vehicle occupants can not understand the operation mode switching and the drivability can be remarkably improved.

As described above, when the cylinder cutoff operation execution condition is not satisfied, for example, when the engine load increases after the cylinder cutoff operation is started, NO is determined in step ST1, the processing flow goes to step ST7, and all cylinder operation is executed. In other words, when assuming a state in which the cylinder cut-off operation execution condition is not satisfied, the cylinder cut-off operation mode is switched to the all cylinder operation mode.

When the cylinder cut-off operation is executed, NO is determined in step ST2, the processing flow goes to step ST5, and it is determined whether the temperature of the first catalytic converter 82L is less than the predetermined total cylinder operation recovery temperature (T2). In other words, it is determined whether the temperature of the first catalytic converter 82L has dropped to near the lower limit of the activation temperature.

The total cylinder operation recovery temperature (T2) is set at a temperature about 50 ° higher than the lower limit of the activation temperature (for example, 450 °) of the first catalytic converter 82L is. However, these values are not limiting.

When the temperature of the first catalytic converter 82L is equal to or greater than the total cylinder operation recovery temperature (if NO is determined in step ST5), the cylinder deactivation operation is maintained.

When the temperature of the first catalytic converter 82L is less than the total cylinder operation recovery temperature and YES is determined in step ST5, the processing flow goes to step ST7, and the overall cylinder operation is executed to avoid deterioration of the exhaust emission during the overall cylinder operation restoration.

As described above, in the present embodiment, when the cylinder cut-off operation execution condition is satisfied in the execution process of the overall cylinder operation and the temperature of the first catalytic converter 82L is less than the predetermined required preheat temperature, first the catalyst preheat operation is performed to the temperature of the first catalytic converter 82L to increase to a temperature equal to or higher than the required preheat temperature, instead of starting the skip-off operation immediately after the skip-off operation execution conditions are satisfied. After the temperature of the first catalytic converter 82L is increased to a temperature equal to or higher than the required preheating temperature by the execution of the catalyst preheating operation, the skip-off operation is started. Consequently, even if the temperature of the first catalytic converter 82L decreases gradually during the cylinder cut-off operation, the time required to decrease this temperature to a temperature at which the restoration of the all cylinder operation is necessary (the total cylinder operation recovery temperature) is prolonged because the cylinder cutoff operation enters a state of a comparatively high temperature of the first catalytic converter 82L is started. In this way, the operation period of the cylinder cut-off operation can be prolonged. Advantages of the engine system where the cylinder cut-off operation can be performed can be fully utilized, and the fuel consumption ratio improving effect as well as the fuel consumption amount reducing effect can be fully exhibited.

In the present embodiment, since the torque of the engine E gradually decreases during the catalyst preheat operation, a new shift operation from the all-cylinder operation to the cylinder-cut operation causing almost no vibration during the operation mode shift can be realized.

A modified example of the catalyst preheating operation will be explained below. In the above-described embodiment, the deceleration operation of the ignition timing of the cylinders (cylinders to be shut down) that are in an inoperative state during the cylinder cutoff operation is executed as the catalyst preheat operation. However, instead of carrying out the catalyst preheat operation described below, it is also within the technical scope of the invention.

First, ignition of the spark plugs will not be ignited with respect to the cylinders (cylinder to be shut down) which will be in a shut-down state during the cylinder cut-off operation 77L executed. In other words, during the catalyst preheat operation with respect to the cylinders to be shut down, only one fuel supply and no ignition of the spark plug 77L executed.

In this way, a majority of the air-fuel mixture contained by the cylinder passes as an unburned gas into the exhaust pipe 81L , Thermal energy of the first catalytic converter 82L is taken up by the mixture and the mixture is burned (oxidation reaction). In this case, similarly to the catalyst preheating operation of the above-described embodiment, the temperature of the first catalytic converter can also be raised within a short time to a temperature equal to or higher than the required preheating temperature. Further, in this case, almost the entire amount of the fuel supplied during the catalyst preheating operation period may be used to respond to the temperature increase of the first catalytic converter 82L to contribute. In this way, the amount of fuel used for catalyst preheat operation can be reduced to a required minimum.

Thus, a certain thermal energy must be within the first catalytic converter 82L be present when the catalyst preheat operation by non-ignition of the spark plug 77L is performed. Consequently, this operation is carried out after the temperature of the first catalytic converter 82L was detected or estimated and the presence of sufficient thermal energy to combust the air-fuel mixture within the first catalytic converter 82L was confirmed. In other words, the temperature at which the air-fuel mixture is within the first catalytic converter 82L can burn, as the lower limit of the activation temperature (T3) is set.

As another modified example of the catalyst preheating operation, the fuel injection timing of the injector becomes 75L which supplies fuel to the cylinders (cylinders to be shut down) that are in the off-state cylinder-off state, when the engine E is a direct-injection gasoline engine.

In other words, the fuel injection timing of this injector becomes 75L moved towards late. For example, if the fuel injection timing is at a timing that is approximately equal to the spark timing of the spark plug 77L is retarded, the combustion start timing moves late due to the delay in the cylinders to be shut down. Further, when the fuel injection timing is later than the spark timing of the spark plug 77L is shifted, no combustion is carried out within the cylinder. In any case, the air-fuel mixture burns in the exhaust pipe 81L and in the first catalytic converter 82L , Consequently, the temperature of the first catalytic converter 82L can be increased rapidly and the effect similar to the embodiment described above can be shown.

After the catalyst preheat operation has been started, the retard amount of the fuel injection timing may be gradually increased. For example, the ignition timing is retarded every 10 revolutions of the crankshaft C by 1 ° CA (1 ° crank angle). However, this value is not limitative and can be determined in advance by a test or a simulation.

In the above embodiments, a case is described in which the invention is applied to a V-type engine for a vehicle. However, the invention is not limited to this application and can also be applied to a boxer engine or an in-line engine for an automobile. Further, the invention can be applied not only to a gasoline engine but also to a diesel engine. When applied to a diesel engine, the catalyst preheat operation is controlled late by controlling the injection firing timing from the injector because engines of this type are not usually equipped with spark plugs. Furthermore, the invention is not limited to the number of cylinders in the engine, the fuel injection system nor to technical characteristics of the engine E.

In the embodiment described above, as the catalyst preheating operation, the Ignition timing of the cylinder to be shut off gradually shifted towards late. However, the invention is not limited to this application, and it is also possible to delay the ignition timing of the cylinders to be turned off simultaneously with the start of the catalyst preheating operation and thus maintain an ignition timing (until the temperature of the first catalytic converter 82L reaches the required preheat temperature).

The invention may be applied to a vehicle engine in which the cylinder deactivation mode may be executed, to a controller that is executed during a shift from a full cylinder operating mode to a cylinder deactivation operating mode.

Although the invention has been described with reference to exemplary embodiments of the invention, the invention is not to be limited to the described embodiments or constructions. On the contrary, the invention is intended to cover various modifications and corresponding arrangements. While various elements of the example embodiments are shown in various combinations and configurations, other combinations and configurations, as well as the addition or omission of individual elements are within the scope of the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2005-351134 A [0002, 0004, 0007, 0011, 0011]
• JP 2001-227369 A [0002, 0005, 0007, 0011, 0012]
• JP 2001-182601 A [0002, 0006, 0011, 0013]

Claims (6)

An operation control apparatus for a multi-cylinder internal combustion engine provided with a first catalyst provided in a first exhaust passage connected to at least one of a plurality of cylinders and a second catalyst provided in a second exhaust passage connected to the other cylinders, and wherein the at least one cylinder is driven by a cylinder deactivation operation is disabled when a predetermined Zylinderabschaltbetrieb execution condition is met, characterized in that the apparatus comprises: a catalyst temperature detecting means for detecting or estimating a temperature of the first catalyst; and a catalyst preheating operation execution means for executing a catalyst preheating operation to raise a temperature of the first catalyst to a temperature equal to or greater than a preheating temperature required before the skip-off operation is executed, in a case that the skip-off operation execution condition is satisfied, the temperature of the first catalyst detected or estimated by the catalyst temperature detecting means is smaller than the predetermined required preheating temperature. 3. The operation control device for a multi-cylinder internal combustion engine according to claim 1, wherein the catalyst preheat operation execution means is configured to advance a catalyst preheat operation by spark advance of a spark plug of the at least one cylinder deactivated during the cylinder cutoff operation, or non-ignition catalyst preheat operation, prior to executing the cylinder deactivation operation to perform the spark plug. The operation control apparatus for a multi-cylinder internal combustion engine according to claim 2, wherein before the cylinder deactivation operation, the catalyst preheat operation delays the ignition timing of the spark plug of the at least one cylinder which is put out of operation during the skip-off operation and gradually increases a retard amount of the ignition timing, thereby decreasing from combustion Air-fuel mixture produced energy gradually reduces a participating in a torque generation in the internal combustion engine amount of kinetic energy and increasing a share in the catalyst preheating thermal energy amount is gradually increased. The operation control apparatus for a multi-cylinder internal combustion engine according to claim 1, wherein a catalyst preheat operation execution means is arranged to execute a catalyst preheat operation by fuel supply timing shift of the at least one cylinder, which is put out of operation during the cylinder cut-off operation, running late before performing the Zylinderabschaltbetriebs. The operation control apparatus for a multi-cylinder internal combustion engine according to any one of claims 1 to 4, wherein during the cylinder deactivation operation, when the temperature of the first catalyst has dropped to a predetermined total cylinder operation recovery temperature, a shift from cylinder deactivation operation to total cylinder operation is performed; and the overall cylinder operation recovery temperature is set to a temperature higher than a lower limit of an activation temperature of the first catalyst at which the air-fuel mixture inside the first catalytic converter can burn and which is lower than the required preheat temperature. An operation control method for a multi-cylinder internal combustion engine provided with a first catalyst provided in a first exhaust passage connected to at least one of a plurality of cylinders and a second catalyst provided in a second exhaust passage connected to the other cylinders, and wherein the at least one cylinder is driven by a cylinder deactivation operation is disabled, characterized in that the method comprises: Determining whether a predetermined cylinder deactivation operation execution condition is satisfied; Detecting or estimating a temperature of the first catalyst; and Performing a catalyst preheating operation to raise a temperature of the first catalyst to a temperature equal to or higher than a preheating temperature before the skip-off operation is executed, in a case that the skip-off operation execution condition is satisfied, the detected or estimated temperature of the first catalyst first catalyst is less than the predetermined required preheat temperature.

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