JP2009036173A - Exhaust emission control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a desired exhaust gas temperature and a desired exhaust gas air-fuel ratio without increasing the output of an engine when the rise of an exhaust gas temperature or the rich of an exhaust gas air-fuel ratio according to the state of a NOx trap catalyst is requested. <P>SOLUTION: Using a cylinder control means (intake cut-off valve 6) stopping a part of cylinders by stopping the inflow/outflow of gas and the supply of fuel in each cylinder of an engine 1, the quantity of the stopped cylinders and the outputs of the operating cylinders are determined and controlled according to the request and the output requested from the engine 1 when requested. Also, the cylinder control means controls the air-fuel ratio of the exhaust gas discharged from the operating cylinders and flowing to the NOx trap catalyst 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust purification control apparatus for an internal combustion engine, and more particularly to an exhaust purification control apparatus for an internal combustion engine that can be suitably used in a hybrid vehicle.

  In a hybrid vehicle comprising a drive source of an internal combustion engine and a motor generator and having an exhaust purification component such as a catalyst device for purifying exhaust exhausted when the internal combustion engine is operated in an exhaust system of the internal combustion engine, the catalyst device When the internal combustion engine is in a stopped state, the temperature of the catalyst device is lower than a predetermined value, and the remaining power of the battery is higher than the predetermined value, the internal combustion engine is In preparation for starting the engine, the catalyst device is heated by the heating means with the electric power of the battery. On the other hand, when the remaining power of the battery is below a predetermined value, the internal combustion engine is forcibly started.

  Also, when the internal combustion engine is already in operation and the temperature of the catalyst device is lower than a predetermined value, and the battery is sufficiently charged and cannot be charged, the catalyst device is heated by the heating means and the battery can be charged. Then, the structure which keeps the temperature of a catalyst apparatus more than activation temperature by increasing the output of an internal combustion engine is proposed (refer patent document 1).

  In recent years, lean burn gasoline engines, direct injection gasoline engines, diesel engines, and the like have attracted attention from the viewpoint of improving the fuel consumption rate or reducing CO2.

Further, as an exhaust purification catalyst for an internal combustion engine mainly composed of lean combustion, a NOx trap catalyst that adsorbs NOx in the exhaust when the exhaust air-fuel ratio is lean has been proposed. This NOx trap catalyst has a purification performance. Therefore, before the NOx adsorption amount saturates, the exhaust air-fuel ratio is periodically made rich to form a reducing atmosphere so that the adsorbed NOx is desorbed and purified. Further, since the purification performance of the NOx trap catalyst is deteriorated also by poisoning with sulfur (S) contained in the fuel, the S poisoning is periodically released at a high temperature and in a stoichiometric atmosphere (Patent Document 2). reference).
Japanese Patent No. 3376902 JP 2000-018026 A

  By the way, in the configuration described in Patent Document 1, when the internal combustion engine is already in operation and the temperature of the catalyst device is lower than a predetermined value and the battery cannot be charged, the catalyst device is heated by the heating means. In the state where the battery can be charged, the output of the internal combustion engine is increased so that the temperature of the catalytic device is maintained at the activation temperature or higher. When it is applied to a diesel engine, the exhaust gas flow rate is higher than that of a premixed gasoline engine, and particularly in the case of a diesel engine, the exhaust gas temperature is much higher and the heat efficiency is higher, so the exhaust temperature is lower. For this reason, even if the internal combustion engine is operated and the catalyst device is activated only by a heating means such as a heater, a heater with very large power consumption is required, and the battery capacity needs to be increased with a margin. Resulting in increased costs.

  For this reason, in such a case, increasing the output of the internal combustion engine to raise the exhaust gas temperature to bring the catalyst device to an activation temperature or higher can simplify the system and improve the efficiency or improve the purification performance of the catalyst. Is effective.

  However, as described above, in the case of using a NOx trap catalyst as the exhaust purification catalyst, particularly in the case of a diesel engine, in order to promote warm-up for improving the catalyst activity or to maintain the purification performance, However, it is necessary to continuously operate at a high temperature and in a stoichiometric atmosphere for a predetermined time in order to desorb and purify NOx by making the exhaust air-fuel ratio rich, or to remove the S poison of the catalyst, but the exhaust flow rate is large. The low exhaust temperature creates a large increase in fuel consumption in creating these conditions, resulting in difficulty in controllability. In particular, when these are applied to hybrid vehicles, surplus output is likely to occur, and there are many opportunities for power generation by surplus output. Therefore, if all the generated power is charged to the battery, the battery becomes overcharged and the charge / discharge function is activated. Therefore, when the charge level is high, a surplus output cannot be absorbed and a state that must be discarded occurs, resulting in a serious problem that energy efficiency is lowered.

  In view of such a situation, the present invention promotes warm-up for improving the catalyst activity, periodically enriches the exhaust air-fuel ratio in order to maintain the purification performance, desorbs and purifies NOx, Alternatively, when it is necessary to continuously operate at a high temperature and in a stoichiometric atmosphere for a predetermined time in order to cancel S poisoning of the catalyst, a desired exhaust temperature and exhaust air / fuel ratio can be obtained without increasing the output of the internal combustion engine. The exhaust gas purification control device for an internal combustion engine that can improve the purification performance of an exhaust gas purification catalyst (NOx trap catalyst, etc.), while preventing overcharge of the battery and suppressing a decrease in energy efficiency in the case of a hybrid vehicle The purpose is to provide.

  Therefore, in the present invention, some cylinders can be stopped by stopping gas inflow and outflow and fuel supply in each cylinder of the internal combustion engine, and the exhaust temperature or exhaust gas based on the state of the exhaust purification catalyst Cylinder control means for determining and controlling the number of stopped cylinders and the output of the working cylinder according to the request and the required output of the internal combustion engine when the air-fuel ratio is requested, and exhaust purification exhaust gas discharged from the working cylinder And an exhaust air / fuel ratio control means for controlling the air / fuel ratio of the exhaust gas flowing into the catalyst.

  According to the present invention, when exhaust temperature or exhaust air-fuel ratio is requested based on the state of the exhaust purification catalyst, specifically, when catalyst activity enhancement is requested (when warming-up promotion is requested), for NOx reduction desorption purification. The overall output of the internal combustion engine is controlled by cylinder control that stops gas inflow and fuel supply to some cylinders and increases the output of the working cylinder when a catalyst regeneration request or an S poison release request is made. Since the required exhaust temperature and exhaust air / fuel ratio can be obtained without increasing the amount of exhaust gas, it is possible to improve the purification performance without eliminating wasteful energy consumption and reducing the efficiency. Further, even when applied to a hybrid vehicle, since a heater with a large power consumption or a battery with a large capacity is not required, the system can be simplified and an increase in cost can be suppressed.

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

  FIG. 1 is a system configuration diagram showing an embodiment of a diesel engine exhaust gas purification control apparatus according to the present invention, which is applied to a hybrid vehicle system, particularly a parallel hybrid electric vehicle (P-HEV). FIG.

  In FIG. 1, the hybrid vehicle travels with the power of a diesel engine 1 and a motor generator 53 (hereinafter referred to as “MG2”) that serves as both a vehicle drive motor and a power generator.

  The output of the diesel engine 1 is transmitted to a motor generator 51 (hereinafter referred to as “MG1”) for power generation, and a differential gear 54 is transmitted from a power transmission mechanism (for example, a continuously variable transmission with an electromagnetic clutch; CVT) 52 for vehicle travel. To the drive wheels 55a and 55b.

  When the vehicle is decelerated and braked, MG1 · 51 and MG2 · 53 are effectively used as generators, and the vehicle braking force is converted into electric energy and collected, and the battery 50 is charged.

  The output distribution of the diesel engine 1 for power generation and vehicle travel is controlled by the hybrid control unit 40. The hybrid control unit 40 also controls the supply of electric power from the battery 50 to the MGs 2 and 53 and, conversely, the recovery of regenerative electric power from the MGs 1 and 51 and the MG 2 and 53 to the battery 50 during deceleration.

  In order to monitor the vehicle running (stop) information, the hybrid control unit 40 detects a signal from the accelerator sensor 41 (L: an output signal proportional to the amount of depression of the accelerator pedal), a signal from the start key 42 (STA: Acc position and Signal corresponding to the ON position), signal of the shift lever position sensor 43 (SFT), signal of the brake operation switch 44 (BR), signal of the vehicle speed sensor 45 (vehicle speed V), signal of the battery remaining amount sensor 46 (remaining battery amount) SOC) or the like is input to determine whether or not the engine 1 needs to be started and output sharing is performed, and a start command and an output sharing command are issued to the engine control unit 30. In accordance with the command, the engine control unit 30 sets the operating point of the diesel engine 1 and controls the start, stop, and output.

  The diesel engine 1 includes an exhaust purification post-treatment device 20 that purifies engine exhaust gas in the exhaust passage 3. The exhaust purification post-treatment device 20 includes a lean NOx trap catalyst (hereinafter referred to as “LNT”) 21.

  The LNT 21 is a NOx trap catalyst that adsorbs NOx when the air-fuel ratio of the inflowing exhaust gas is lean and releases / reduces and purifies NOx when the oxygen concentration of the inflowing exhaust gas decreases, and has an oxidation function such as HC and CO. In addition, noble metals such as Pt, Pd, and Rh, and Ba, Mg, Cs, and the like are used as NOx adsorbents. Further, an electric heating type catalyst (hereinafter referred to as “EHC”) is employed as a heating means for enhancing the catalytic activity.

  A temperature sensor 35 is provided near the LNT 21 at the inlet of the LNT 21, and detects the EHC temperature as Tex when the engine 1 is stopped and the exhaust temperature during operation of the engine 1. This is provided to detect the activity of the LNT 21. The activity of the LNT 21 is not only the temperature of the LNT (EHC) 21, the exhaust temperature of the inlet side of the LNT 21, but also the exhaust temperature of the outlet side of the LNT 21. May be detected based on, for example, the outlet side exhaust gas temperature of the working cylinder.

  An oxygen concentration sensor 36 that detects the oxygen concentration O2 is provided at the outlet of the LNT 21.

  A turbocharger turbine 3a is arranged in the middle of the exhaust passage 3 (upstream side of the LNT 21), and an EGR valve 5 is provided in the EGR passage 4 branched from the upstream side. The EGR valve 5 is driven by a stepping motor (not shown), and a part of the exhaust gas is recirculated to the intake pipe 2 d of the intake passage 2.

  The intake passage 2 includes, from upstream, an air cleaner 2a, a supercharger compressor 2b, an intercooler 2c, an intake throttle valve 7 that is driven to open and close by an actuator (for example, a stepping motor), and an intake pipe 2d. In the branch pipe, there is provided an intake shut-off valve 6 that independently opens and closes each branch pipe by an actuator (for example, a stepping motor).

  The fuel supply system includes a fuel tank 60 for storing diesel fuel (light oil), a fuel supply passage 16 for supplying fuel from the fuel tank 60 to the fuel injection device 10 of the engine, and a return fuel from the fuel injection device 10 of the engine. A fuel return passage 19 for returning (spill fuel) to the fuel tank 60 is provided.

  The fuel injection device 10 of the diesel engine 1 is a known common rail type fuel injection device, and includes a supply pump 11, a common rail (accumulation chamber) 14, and a fuel injection valve 15 provided for each cylinder. The fuel pressurized by the supply pump 11 is temporarily stored in the common rail 14 through the fuel supply passage 12 in a high pressure state, and then distributed to the fuel injection valves 15 corresponding to the number of cylinders.

  The pressure of the common rail 14 is controlled by the pressure control valve 13. That is, the pressure control valve 13 has an overflow passage 17 that returns part of the fuel discharged from the supply pump 11 to the fuel supply passage 16 via the one-way valve 18 in response to a duty signal from the engine control unit 30. By changing the flow path area, the fuel discharge amount to the common rail 14 is adjusted, and the pressure of the common rail 14 is controlled.

  The fuel injection valve 15 is an electronic injection valve that opens and closes a fuel passage to the engine combustion chamber in response to an ON-OFF signal from the engine control unit 30, and injects fuel into the combustion chamber in response to an ON signal. To stop the injection. The fuel injection amount increases as the ON signal to the fuel injection valve 15 becomes longer, but also changes depending on the fuel pressure of the common rail 14 as will be described later.

  Further, a glow plug 24 for assisting engine start is provided facing the combustion chamber of each cylinder of the diesel engine 1.

  Further, an electric heating type block heater 70 is provided so as to face the cooling water path of the diesel engine 1 in order to promote warming up of the diesel engine 1.

  The engine control unit 30 detects a signal (Tw) of the water temperature sensor 31, a signal of the crank angle sensor 32 (engine speed and crank angle detection Ne), a signal of the cam angle sensor 33 (cylinder discrimination signal Cyl), and a common rail pressure. The signal (PCR) of the pressure sensor 34, the signal (Tex) of the temperature sensor 35, and the signal (O2) of the oxygen concentration sensor 36 are input. The specific control of the engine control unit 30 will be described later.

  The exhaust purification control apparatus of the present invention is controlled by the hybrid control unit 40 and the engine control unit 30, which will be described with reference to the flowcharts of FIGS.

  FIG. 10 is a basic control routine of the hybrid system, and FIGS. 11 to 24 are subroutines related to the output control of the diesel engine 1 performed by the engine control unit 30 in accordance with a command from the hybrid control unit 40 and the exhaust purification control of the present invention. Indicates.

  In the basic control routine of the hybrid system of FIG. 10, in step 100, the signal (L) of the accelerator sensor 41, the signal (STA) of the start key 42, the signal (SFT) of the shift lever position sensor 43, the signal of the brake operation switch 44 (BR), a signal (V) of the vehicle speed sensor 45, a signal (SOC) of the battery remaining amount sensor 46, and a signal (Tw) of the water temperature sensor 31 and a signal of the crank angle sensor 32 (engine speed and crank angle detection). Ne), a signal from the cam angle sensor 33 (cylinder discrimination signal Cyl), a signal from the pressure sensor 34 that detects common rail pressure (PCR), a signal from the temperature sensor 35 that detects EHC temperature or exhaust temperature (Tex), and an oxygen concentration sensor 36 signal (O2) is read and the routine proceeds to step 200.

  In step 200, as shown in FIGS. 4 and 5, the driving force required for vehicle travel according to the depression amount (L) of the driver's accelerator pedal (Prun: point ae line in the figure), That is, the driving force required for the vehicle traveling that the driver is seeking by the accelerator operation is calculated, and the process proceeds to step 201.

  In step 201, the remaining amount (SOC; State of Charge) of the battery 50 is equal to or higher than a predetermined value SOC1 at which the rated power of the battery can be stably supplied, and the charge upper limit set value SOC2 (for example, about 80% of full charge) If the determination is Yes and the surplus power processing is necessary to prevent overcharging of the battery 50, the process proceeds to step 1300, and No is surplus. If power processing is not necessary, the process proceeds to step 300.

  In step 300, the normal hybrid operation mode is determined based on the driving force (Prun), vehicle speed (V), remaining battery level (SOC), and the like necessary for vehicle travel calculated in step 200. The hybrid operation mode is basically divided into the following five patterns of Modes 0 to 4 as shown in FIGS.

<Motor travel mode: Mode 1>
Basically, as shown in FIG. 9, the motor travel is performed at a first predetermined temperature Tex1 (for example, about 200 ° C., NOx adsorption activity, HC, CO, and the like, when the engine travels, the load is low and the exhaust temperature Tex is the catalyst activation temperature. A predetermined value SOC1 that can supply the rated power of the battery with a stable remaining amount (SOC) of the battery 50 by sharing the driving force by the motor alone in the catalyst low activity region A where the oxidation activity of A is not obtained). If it is above, it drive | works with B1 (point ab) of FIG. 4 with the driving force of MG2 * 53 (or MG1 * 51).

<Engine running mode: Mode 2>
In the engine running, when the remaining amount (SOC) of the battery 50 is more than SOC1 capable of stably supplying electric power and charging is unnecessary, the driving force is shared only by the output of the engine 1. In this case, as shown in FIG. 9, engine operation (setting of the load and the rotational speed) is performed in a region B where the temperature is equal to or higher than a first predetermined temperature Tex1, which is a predetermined exhaust temperature at which high catalytic activity is obtained. Includes the best fuel efficiency regions E and F with good thermal efficiency.

  Normally, when the exhaust gas temperature Tex is equal to or higher than the first predetermined temperature Tex1, which is the catalyst activation temperature, in the state of the engine output lower limit set value b, the engine travels at B2 (point bd) in FIG.

  Further, as described above, when the engine output lower limit set value b is not equal to or higher than the first predetermined temperature Tex1 that is the catalyst activation temperature under conditions such as a low engine temperature, the engine operation is performed as described later. (Stop) Cylinder control is performed by determining the number of cylinders and the load (output) of the cylinder to be operated.

<Engine output split mode: Mode3>
When the remaining amount (SOC) of the battery 50 is lower than the SOC 1 that can stably supply power, the engine is operated and its output is divided for vehicle travel and power generation.

  Also in this case, the first predetermined temperature Tex1 or higher that is the catalyst activation temperature is obtained in the state of the engine output lower limit set value b so that the first predetermined temperature Tex1 or higher that is the catalyst activation temperature is obtained during engine operation. In this case, the engine is operated so as to obtain an output higher than the driving force (Prun) required for traveling the vehicle at B2 (point bd) in FIG. 4, and the engine output (Pe) and the required driving force are obtained. The difference from (Prun) is used for power generation, and power is generated by MG1 · 51 to charge the battery 50.

  Further, as described above, when the engine output lower limit set value b is not equal to or higher than the first predetermined temperature Tex1 that is the catalyst activation temperature under conditions such as a low engine temperature, engine cylinder control described later is performed, The engine 1 is operated so that an output higher than the driving force (Prun) necessary for traveling the vehicle is obtained, and the difference between the engine output (Pe) and the required driving force (Prun) is used for power generation.

<Motor assist mode: Mode 4>
The driving force range B3 in FIG. 4 is the motor assist mode. That is, since the maximum output of the engine is set at the d point in the good fuel efficiency region as shown in FIG. 9, no more power can be supplied from the engine. Therefore, the engine 1 is operated at the point d, and the difference from the point d to the point e (Prunmax) of the vehicle driving maximum driving force is supplemented by the output of MG2 · 53.

  The assist by the motor is not limited to this, and the engine 1 may be operated at the point b-d and MG2 · 53 may be used in combination.

<Deceleration regeneration mode: Mode 0>
MG1 · 51 and MG2 · 53 function as a generator at the time of deceleration, collect kinetic energy at the time of deceleration as electric power, and charge the battery 50.

  This is the end of the description of the hybrid operation mode determination in step 300, the relationship between the engine operating region, the driving force range necessary for vehicle travel, and each engine operating point. In the motor travel mode Mode1, the power transmission mechanism 52 is disconnected (for example, by an electromagnetic clutch of a CVT with an electromagnetic clutch).

  On the other hand, if the determination in step 201 is Yes and the surplus power processing is necessary, the process proceeds to step 1300 and the surplus power processing operation mode is determined based on the remaining battery level (SOC). As shown in FIGS. 3 and 5, the pattern is basically divided into the following three patterns of Modes 10 to 30.

<Motor running mode: Mode 10>
The motor travel mode Mode10 is basically the same as Mode1 in the normal hybrid operation mode, and travels along B1 (point ab) in FIG. 5 with a driving force of MG2 · 53 (or MG1 · 51).

<Motor assist mode: Mode 20>
Since the remaining amount (SOC) of the battery 50 is equal to or higher than the charge upper limit set value SOC2, it is necessary to process surplus power in order to prevent the battery 50 from being overcharged with an appropriate charge / discharge balance. For this reason, when the required driving force (Prun) is equal to or greater than b points and falls below the total value d points of the engine output lower limit set value b and the motor maximum output (output width = ab in FIG. 5), the required drive The motor travels the difference between the power (Prun) and the engine output lower limit setting b to consume surplus power.

  Also in this case, as described above, when a temperature equal to or higher than the first predetermined temperature Tex1 that is the catalyst activation temperature cannot be obtained under the conditions such as the low engine temperature, the cylinder control of the engine described later is performed.

<Engine output increase mode: Mode 30>
If the required driving force (Prun) exceeds the total value d point of the engine output lower limit setting b and the motor maximum output (output width a-b), the engine output is requested to increase up to the maximum driving force point e. Satisfy driving force (Prun).

  Also in this case, as described above, when a temperature equal to or higher than the first predetermined temperature Tex1 cannot be obtained under conditions such as a low engine temperature, cylinder control of the engine, which will be described later, is performed.

  Returning again to FIG.

  After the determination of the normal operation mode in step 300, the process proceeds to step 400, and the shared outputs of the MG2 53 and the engine 1 (based on the driving force (Prun) necessary for vehicle travel and the travel mode determined) After calculating Pm and Pe), go to step 500.

  After determining the surplus power processing operation mode in step 1300, the process proceeds to step 1400, and based on the driving mode (Prun) necessary for vehicle traveling and the traveling mode determined, the MG2 53 and the engine 1 After the shared outputs (Pm and Pe) are calculated, the process proceeds to step 500.

  In step 500, it is determined whether or not there is a need to operate the engine 1 (engine sharing request). When this determination is No and the engine operation is not required (the motor travel mode Mode1 in the normal operation mode, the deceleration regeneration mode Mode0, and the motor travel mode Mode10 in the surplus power processing operation mode), the process proceeds to Step 800, where the engine 1 Control at stop (stop operation control).

  That is, the hybrid control unit 40 issues a stop command to the engine control unit 30. The engine control unit 30 performs stop control of the engine 1 in accordance with the stop command.

  When the determination in step 500 is Yes and the engine 1 needs to be operated (the engine running mode Mode2, the engine output split mode Mode3, the motor assist mode Mode4 in the normal operation mode, and the motor assist mode Mode20 in the surplus power processing operation mode) The engine output increase mode Mode 30) proceeds to step 600.

  In step 600, it is determined whether or not the engine 1 has already been started (engine is running). When this determination is Yes and the engine 1 is already in operation, that is, the output command has already been transmitted from the hybrid control unit 40 to the engine control unit 30, and the engine control unit 30 performs the engine operation according to the command. When the output control 1 is being performed, the process proceeds to step 900.

  In step 900, the cylinder control for determining and controlling the number of operating (stopped) cylinders of the engine and the load (output) of the operating cylinders, and the exhaust air-fuel ratio discharged from the operating cylinders (flowing into the exhaust purification catalyst) are controlled. The engine 1 output control for obtaining the engine sharing output (Pe) calculated in Step 400 or Step 1400 is continued or started.

  On the other hand, if the determination in step 600 is No and the engine 1 has not yet been started, the routine proceeds to step 700, where engine start control (start operation control) is performed (start command is issued).

  This starting operation is also controlled by the hybrid control unit 40 and the engine control unit 30.

  After performing the engine output control in step 900, the engine start operation control in step 700, or the engine stop operation control in step 800, the process proceeds to step 1000.

  In step 1000, the hybrid control unit 40 performs power generation control of the MG1 · 51 or MG2 · 53 based on the operation mode.

  Then, the process proceeds to step 1100, and the motor driving force (Pm = Prun-Pe) calculated in step 400 based on the travel mode is output to MG2 · 53.

  Finally, the process proceeds to step 1200, and gear ratio control and ON-OFF control of the power transmission mechanism 52 (for example, CVT with an electromagnetic clutch) are performed based on the travel mode, the vehicle speed (V), and the like.

  FIG. 11 is a flowchart showing a subroutine for calculating the driving force (required driving force) necessary for vehicle travel in step 200 (FIG. 10).

  In the required driving force calculation routine of FIG. 11, it is determined in step 211 whether the signal STA of the start key 42 is ON, and in step 212, the signal SFT of the shift lever position sensor 43 is ON (that is, the Drive position). In step 213, it is determined whether the signal BR of the brake operation switch 44 is OFF (that is, the brake is released), but basically the determination of the signal STA of the start key 42 in this case is Yes. In the ON position, the determination of the signal SFT of the shift lever position sensor 43 is Yes and the drive position, the determination of the signal BR of the brake operation switch 44 is Yes and the brake is OFF, Since the vehicle is ready to travel, the process proceeds to step 220. The driving force (Prun) required for vehicle travel from predetermined table data according to the depression amount (L) of the driver's accelerator pedal, that is, the drive required for vehicle travel required by the driver by the accelerator operation Calculate the force and return.

  On the other hand, if any of the determinations in Steps 211, 212, and 213 is No and the vehicle is not in a state where it can travel, the process proceeds to Step 230 to stop operations necessary for vehicle travel (MG1 · 51 and MG2). (53) Stop driving, disconnect the power transmission mechanism 52, stop the engine 1, and return to the return to the basic control routine of FIG.

  FIG. 12 is a flowchart showing a subroutine for the normal operation mode determination in step 300 (FIG. 10).

  In the normal operation mode determination routine of FIG. 12, in step 310, it is determined whether the vehicle is running (whether the vehicle speed V is equal to or greater than 0), and if No and the vehicle is stopped, the process proceeds to step 315.

  In Step 315, it is determined whether the required driving force (Prun) is 0 (point a) or more. If No and the required driving force (Prun) is 0, the process proceeds to Step 230 in FIG. Stop the operation required for vehicle travel.

  If YES in step 310 and the vehicle is traveling, and if YES in step 315 and the required driving force (Prun) is 0 (point a) or more, the process proceeds to step 311.

  In Step 311, it is determined whether the required driving force (Prun) is less than the point d. If No, the process proceeds to Step 316 to determine the motor assist mode (Mode 4) and return.

  If Yes in step 311 and the required driving force (Prun) is less than the point d, the process proceeds to step 312.

  In step 312, it is determined whether the remaining amount (SOC) of the battery 50 is at a level equal to or higher than a first predetermined value SOC1 at which power can be supplied stably. In order to charge the battery 50, the routine proceeds to step 317, where the engine output division mode (Mode 3) is determined and the routine returns.

  If YES in step 312, the process proceeds to step 313 if the remaining amount (SOC) of the battery 50 is equal to or higher than the first predetermined value SOC1 at which electric power can be stably supplied.

  In Step 313, it is determined whether the required driving force (Prun) exceeds the point b. If Yes, the engine travel mode (Mode 2) is satisfied, so that the process proceeds to Step 318 to determine the engine travel mode (Mode 2). Return.

  If No in step 313 and the required driving force (Prun) is below the point b, the process proceeds to step 314.

  In step 314, it is determined whether the required driving force (Prun) exceeds the point a. If Yes, the process proceeds to step 319, where the motor driving mode (Mode 1) is determined and the process returns.

  On the other hand, when the result is No in step 314 and the required driving force (Prun) is lower than the point a (driving output 0), the process proceeds to step 320 to determine the deceleration regeneration mode (Mode 0) and return.

  FIG. 13 is a flowchart showing a subroutine for calculating the shared output between the motor and the engine in the normal operation mode performed in step 400 (FIG. 10).

  In the shared output calculation routine of FIG. 13, in step 410, it is determined whether or not the motor assist mode (Mode 4). If yes and the motor assist mode (Mode 4), the process proceeds to step 415. Proceed to

  In step 415, the shared output Pe of the engine 1 is set to the engine maximum output d (Pe = d), and the shared output Pm of the MG2 · 53 is set to the difference between the required driving force (Prun) and the engine maximum output d. (Pm = Prun-d), return.

  In step 411, it is next determined whether the engine output division mode (Mode 3) is selected. If the engine output division mode (Mode 3) is Yes, the process proceeds to step 416, and if No, the process proceeds to step 412.

  In step 416, it is determined whether the engine output Pe (Pe = Prun + ΔPe) obtained by adding the engine output ΔPe for the generated power to the required driving force (Prun) exceeds the maximum output point d of the engine 1. If it exceeds d, the routine proceeds to step 417, where the engine output Pe is set to the maximum output point d (Pe = d), and the process returns.

  On the other hand, if No in step 416, the process proceeds to step 418, the engine output Pe is set to the output obtained by adding the engine output ΔPe for the power generation to the required driving force (Prun) (Pe = Prun + ΔPe), and the process returns.

  The output ΔPe for power generation may be a fixed value or may be variable according to the required driving force (Prun).

  In step 412, it is determined whether the engine running mode (Mode 2) is selected. If the engine running mode (Mode 2) is Yes, the process proceeds to step 419, and if no, the process proceeds to step 413.

  In step 419, the engine output Pe is set to the required driving force (Prun) (Pe = Prun), and the process returns.

  In step 413, it is determined whether the motor travel mode (Mode 1) is selected. If the motor travel mode (Mode 1) is determined as Yes, the process proceeds to step 420, and the motor output Pm is changed from the point a to the normal upper limit point based on the required driving force Prun. Set between b and return. On the other hand, if “No” in step 413, the process proceeds to step 414 to give a permission to execute regenerative power generation and then return.

  FIG. 14 is a flowchart showing a subroutine for engine start-up control in step 700 (FIG. 10).

  As shown in FIG. 2, the engine start-up control includes energization control of the glow plug 24, the EHC (LNT) 21, and the block heater 70 in accordance with the level of the remaining amount (SOC) of the battery 50. The purpose is to start the engine most efficiently while appropriately managing charge and discharge according to the level of the remaining amount (SOC).

  For this reason, when the remaining amount (SOC) of the battery 50 is lower than the first predetermined value SOC1 that can supply power stably, only energization control of the glow plug 24 that is at least necessary for starting the engine 1 is performed. .

  If the remaining power (SOC) is in the range from the first predetermined value SOC1 to the second predetermined value SOC2 that is the upper limit threshold value for charging, and there is a surplus of electric power, in addition to the energization control of the glow plug 24, In order to improve the exhaust purification performance, energization control of the EHC 21 is performed. The energization control of the EHC 21 is performed with the goal of obtaining the first predetermined temperature Tex1 necessary for purifying the gas component.

  If the remaining amount (SOC) is equal to or greater than the second predetermined value SOC2, energization control of the block heater 70 is performed to further consume excess power to prevent overcharging of the battery 50 and to improve startability of the engine 1.

  In the engine start-up control routine of FIG. 14, in step 710, it is determined whether the SOC is at a level equal to or higher than the first predetermined value SOC1, and if no, the process proceeds to step 713 to turn off the block heater 70, and then Proceeding to step 714, the EHC 21 is turned off, and the process proceeds to step 740.

  If YES in step 710 and the SOC is at a level equal to or higher than the first predetermined value SOC1, the process proceeds to step 711 to determine whether the SOC is lower than SOC2.

  If YES in step 711 and the SOC is lower than SOC2, the process proceeds to step 712 where the block heater 70 is turned OFF and the process proceeds to step 730.

  If No in step 711 and the SOC is equal to or greater than the second predetermined value SOC2, the process proceeds to step 720 to perform energization control of the block heater 70 (details will be described later with reference to FIG. 15), and then proceeds to step 730.

  In step 730, energization control of the EHC 21 is performed (details will be described later with reference to FIG. 16), and the process proceeds to step 740.

  In step 740, energization control of the glow plug 24 is performed (details will be described later with reference to FIG. 17), and the process proceeds to step 741.

  In step 741, it is determined whether the EHC 21 has reached a predetermined heating stage (determined by the EHC temperature or the exhaust temperature Tex), and if No and has not reached the predetermined heating stage, the process returns.

  If YES in step 741 and the EHC 21 has reached a predetermined heating stage, the process proceeds to step 742 and has the glow plug 24 reached a predetermined heating stage (generally determined by heating time or glow plug temperature)? If NO and the glow plug 24 has not reached the predetermined heating stage, the process returns.

  If Yes in step 742, that is, if both the EHC 21 and the glow plug 24 have reached a predetermined heating stage, the routine proceeds to step 750, where the engine 1 is started.

  In this operation, first, motoring of the engine 1 is started by the MG 1/51. Next, when the motoring rotational speed of the engine 1 reaches a predetermined stable level (reached in a very short time), the pressure control valve 13 and the fuel injection valve 15 of the supply pump 11 are driven to supply fuel suitable for starting. It leads to a complete explosion.

  FIG. 15 is a flowchart showing a subroutine for block heater energization control in step 720 (FIG. 14).

  In the block heater energization control routine of FIG. 15, in step 721, in order to determine whether the engine 1 has reached a predetermined warm-up state, it is determined whether the engine coolant temperature Tw has reached the predetermined temperature Tw1, and in Yes If the predetermined warm-up state has been reached, the routine proceeds to step 722, the energization (cooling water heating) to the block heater 70 is stopped, and a return is made.

  If No in step 721 and the predetermined warm-up state has not been reached, the process proceeds to step 723 to energize the block heater 70 (cooling water heating) and return.

  FIG. 16 is a flowchart showing a subroutine for the EHC energization control in step 730 (FIG. 14).

  In the EHC energization control routine of FIG. 16, in Step 731, it is determined whether the exhaust temperature (or EHC temperature) Tex exceeds the first predetermined temperature Tex1 that is the catalyst activation temperature. If Yes, the process proceeds to Step 732. Returning electricity to the EHC 21 (catalyst heating) is stopped.

  If No in step 731, the process proceeds to step 733, energizes the EHC 21 (catalyst heating), and returns.

  FIG. 17 is a flowchart showing a subroutine for glow plug energization control in step 740 (FIG. 14).

  In the glow plug energization control routine of FIG. 17, in step 741, it is determined whether or not the glow plug temperature (e.g., obtained by the glow plug current) Tglow exceeds a predetermined temperature Tglow1 required for ignition of the injected fuel. If there is, the routine proceeds to step 742, the energization (glow plug heating) to the glow plug 24 is stopped, and a return is made.

  If “No” in step 741, the process proceeds to step 743 to energize the glow plug 24 (glow plug heating) and return.

  FIG. 18 is a flowchart showing a subroutine for engine stop time control in step 800 (FIG. 10).

  In the engine stop time control routine of FIG. 18, in step 810, the fuel supply is stopped (the pressure control valve 13 and the fuel injection valve 15 of the supply pump 11 are turned OFF), and the EGR is also stopped (EGR valve 5, intake throttle valve 7). OFF).

  In step 811, the energization of the glow plug 24, the EHC 21, and the block heater 70 is stopped, and the process returns.

  FIG. 19 is a flowchart showing a subroutine for engine output control in the above-described step 900 (FIG. 10). When an output sharing command is issued from the hybrid control unit 40 to the diesel engine 1, the engine control is executed. Performed by unit 30.

  In the engine output control routine of FIG. 19, in step 910, since the engine is being operated, there is no need for starting assistance, so the energization to the glow plug 24 is stopped and the routine proceeds to step 911.

  In step 911, it is determined whether or not the remaining amount (SOC) of the battery 50 is at a level equal to or higher than a first predetermined value SOC1 at which power can be stably supplied. In order to give priority, the process proceeds to step 912 to stop energization of the block heater 70 and proceeds to step 730.

  If YES in step 911 and the remaining amount (SOC) of the battery 50 is equal to or higher than the first predetermined value SOC1 at which power can be stably supplied, the process proceeds to step 720 and the block heater 70 described above is supplied. Energization control (FIG. 15) is performed, and the process proceeds to step 730.

  In step 730, the above-described energization control to the EHC 21 (FIG. 16) is performed, and the process proceeds to step 913.

  In step 913, it is determined whether regeneration of LNT21 (catalyst regeneration) is necessary.

  If YES in step 931 and the regeneration of the LNT 21 is necessary, the process proceeds to a step 1600, and cylinder stop control for catalyst regeneration (FIG. 23) described later, that is, cylinder control for catalyst regeneration (rich) combustion control of the LNT 21 is performed. And the exhaust air-fuel ratio control is continued or started, and the process proceeds to Step 917.

  In step 917, it is determined whether or not the playback of the LNT 21 has ended (for example, a predetermined time has elapsed). If NO and playback has not ended, the process returns, and if YES and playback has ended, the process proceeds to step 918. Then, a reproduction end operation (for example, reproduction command flag OFF, reproduction time counter reset) is performed, and the process returns.

  Here, the regeneration of the LNT 21 is to regenerate the LNT 21 (release and reduce the adsorbed NOx) by enriching the exhaust air-fuel ratio and raising the exhaust temperature for a short time. In this case, based on the engine rotational speed Ne and the fuel injection amount Qmain, or the oxygen concentration O2 at the outlet of the LNT 21, the EGR is strengthened (EGR is increased and the intake throttle is strengthened) or the post injection (the exhaust air-fuel ratio is enriched). In order to raise the exhaust gas temperature, it is possible to carry out the fuel injection performed in the expansion stroke or the exhaust stroke of each cylinder separately or in combination with the main injection. When the output (Pe) fluctuation occurs, the engine speed necessary to obtain the engine sharing output Pe calculated in step 400 or step 1400 Corresponding by correcting the degree Ne and the fuel injection amount Qmain.

  If No in step 913 and it is not necessary to reproduce the LNT 21, the process proceeds to step 914.

  In step 914, it is determined whether or not SNT poisoning cancellation of LNT21 is necessary.

  If NO in step 914 and S poisoning cancellation is not necessary, the process proceeds to step 940, and the regeneration timing of the LNT 21 is determined.

  Here, the regeneration timing determination of the LNT 21, that is, the determination as to whether NOx release / reduction is necessary is stored in advance in the ROM of the control unit 30 using, for example, the engine speed Ne and the fuel injection amount Qmain as parameters. By searching from predetermined data or the like, the NOx adsorption amount per unit time of the LNT 21 is obtained, and the NOx adsorption amount is integrated at a predetermined time interval synchronized with the NOx adsorption amount per unit time. This can be done by determining whether a predetermined adsorption limit is exceeded.

  After determining the regeneration timing of the LNT 21 in step 940, the process proceeds to step 950, and the S poisoning release timing determination of the LNT 21 is performed.

  Here, the S-detoxication release timing determination of the LNT 21 is performed by searching from predetermined data stored in the ROM of the control unit 30 in advance using, for example, the engine rotational speed Ne and the fuel injection amount Qmain as parameters. By determining the S poison amount per unit time (deposition amount), accumulating the S poison amount per unit time, and determining whether the accumulated S poison amount exceeds the predetermined poison limit amount of LNT21, Is possible.

  After performing the S poison release timing determination of the LNT 21 at step 950, the routine proceeds to step 1500, where normal lean combustion control (FIG. 22) described later is performed, and a return is made.

  If YES in step 914 and the S-toxification release of the LNT 21 is necessary, the process proceeds to a step 1700, the cylinder stop control at the time of S-poisoning release described later (FIG. 24), that is, the LNT 21 poisoning release (stoichiometric) combustion The cylinder control and the exhaust air / fuel ratio control for control are continued or started, and the routine proceeds to step 915.

  In step 915, it is determined whether the S poison removal of the LNT 21 has been completed (for example, a predetermined time has elapsed). If the answer is No and the S poison removal has not been completed, the process returns. When the process is completed, the routine proceeds to step 916, where the S poisoning cancellation end operation (for example, the cancellation command flag is turned off and the cancellation time counter is reset) is returned.

  FIG. 20 is a flowchart showing a subroutine for determining the surplus power processing operation mode in step 1300 (FIG. 10).

  In the surplus power processing operation mode determination routine of FIG. 20, in step 1310, it is determined whether the vehicle is traveling (whether the vehicle speed V is 0 or more), and if it is No and the vehicle is stopped, the process proceeds to step 1314. .

  In step 1314, it is determined whether the required driving force (Prun) is 0 (point a) or more. If No and the required driving force (Prun) is 0, the process proceeds to step 230 in FIG. Stop the operation required for vehicle travel.

  If YES in step 1310 and the vehicle is traveling, and if YES in step 1314 and the required driving force (Prun) is 0 (point a) or more, the process proceeds to step 1311.

  In Step 1311, it is determined whether the required driving force (Prun) is less than the point d. If No, the process proceeds to Step 1315 to determine the engine output increase mode (Mode 30) and return.

  If Yes in step 1311 and the required driving force (Prun) is less than the point d, the process proceeds to step 1312.

  In Step 1312, it is determined whether the required driving force (Prun) exceeds the point b. If Yes, the motor assist mode (Mode 20) is determined and a return is returned.

  If No in step 1312 and the required driving force (Prun) is below the point b, the process proceeds to step 1313.

  In Step 1313, it is determined whether the required driving force (Prun) exceeds the point a. If Yes, the process proceeds to Step 1317, where the motor traveling mode (Mode 10) is determined and the process returns.

  On the other hand, if the answer is No in step 1313 and the required driving force (Prun) is below the point a (driving output 0), the routine proceeds to step 1318, where it is determined that the deceleration regeneration mode has been stopped, and the process returns.

  FIG. 21 is a flowchart showing a subroutine for calculating the shared output between the motor and the engine in the surplus power processing operation mode performed in step 1400 (FIG. 10).

  In the shared output calculation routine of FIG. 21, in step 1410, it is determined whether the engine output increase mode (Mode 30) is selected. If Yes and the engine output increase mode (Mode 30) is selected, the process proceeds to step 1413. Proceed to step 1411.

  In step 1413, the shared output Pm of MG2 · 53 is set to the motor maximum output Pmmax (Pm = Pmmax), and the shared output Pe of the engine 1 is set to the difference between the required driving force (Prun) and the motor maximum output Pmmax. (Pe = Prun-Pmmax) and return.

  In step 1411, it is determined whether the motor assist mode (Mode 20) is selected. If Yes and the motor assist mode (Mode 20) is selected, the process proceeds to step 1414. If the result is No, the process proceeds to step 1412.

  In step 1414, the shared output Pe of the engine 1 is set to the engine output lower limit set value b (Pe = b), and the shared output Pm of MG2 · 53 is the difference between the required driving force (Prun) and the engine output lower limit set value b. (Pm = Prun-b) and return.

  In step 1412, the shared output Pm of MG2 · 53 is set to the required driving force (Prun) (Pm = Prun), and the process returns.

  FIG. 22 shows a subroutine for calculating target values of the engine speed Ne, the fuel injection amount Qmain, and the fuel injection timing ITmain necessary for performing the lean combustion control in the above-described step 1500 (FIG. 19). It is a flowchart.

  In the lean combustion control target value calculation routine of FIG. 22, in step 1501, it is determined whether the exhaust gas temperature Tex is below a first predetermined temperature Tex1 that is the catalyst activation temperature.

  If NO in step 1501 and the temperature is equal to or higher than the first predetermined temperature Tex that is the catalyst activation temperature, the process proceeds to step 1560 to search for predetermined table data and perform normal fuel injection control (same control for each cylinder). Target values for the rotational speed Ne, the main fuel injection amount Qmain, and the fuel injection timing ITmain are calculated. In step 1570, a target value for normal EGR control (drive signals for the EGR valve 5 and the intake throttle valve 7) is obtained, and the process proceeds to step 1540.

  On the other hand, if Yes in step 1501 and the exhaust gas temperature Tex is lower than the first predetermined temperature Tex1 (when catalyst activation enhancement is requested), the process proceeds to step 1502 to determine whether the engine shared output Pe is lower than the predetermined output Pe1. To do.

  If it is No in step 1502 and does not fall below the predetermined output Pe1, the first predetermined temperature Tex1 or higher, which is the catalyst activation temperature, can be obtained quickly without performing the cylinder control, so the process proceeds to the above-described steps 1560 and 1570. Then, normal control is performed.

  If it is Yes in step 1502 and the cylinder control is not performed, if the temperature exceeds the first predetermined temperature Tex1 that is the catalyst activation temperature, the process proceeds to step 1510.

  In step 1510, the preset working cylinder and predetermined table data set for the working cylinder are retrieved, and the rotational speed Ne, the main fuel injection amount Qmain, and the fuel injection timing for performing the fuel injection control of the working cylinder. The target value of ITmain is obtained. In step 1520, a target value for EGR control of the working cylinder (drive signals for the EGR valve 5 and the intake throttle valve 7) is obtained. In step 1530, the operation of the predetermined cylinder is stopped, and the process proceeds to step 1540.

  The cylinder is stopped by using an intake cutoff valve 6 provided in each branch pipe of the intake pipe 2d, and closing the intake cutoff valve 6 of the cylinder to be stopped to shut off the inflow of air or EGR gas. However, it may be performed using a well-known variable valve mechanism.

  In step 1540, the EGR valve 5 and the intake throttle valve 7 are driven and controlled based on the drive signal obtained in step 1520 or step 1570, and the process proceeds to step 1550.

  In Step 1550, based on the data obtained in Step 1510 or Step 1560, common rail pressure control or drive control of the fuel injection valve 15 is performed for fuel injection control, that is, engine output control, and a return is made.

  By the way, the cylinder control in the lean combustion control is performed because the exhaust temperature (or EHC temperature) Tex is lower than the first predetermined temperature Tex1 that is the catalyst activation temperature. Therefore, as shown in FIG. 6 and FIG. The output lower limit value b is in a load range slightly higher than the point b, and in the case of a 4-cylinder engine, only one cylinder is stopped. The reason for this is that if cylinder control is performed, the activity of the catalyst is improved and the combustion efficiency is improved, but the amount of NOx emissions increases, so the number of stopped cylinders is increased to make the load range for cylinder control too high. This is to prevent the NOx emission amount from increasing.

  The common rail pressure control is stored in advance in the ROM of the engine control unit 30 using, for example, the engine speed Ne and the fuel injection amount Qmain (cylinder average or maximum cylinder injection amount when performing combustion control for each cylinder) as parameters. The predetermined reference map is searched to obtain the target reference pressure (PCR0) of the common rail 14 and the reference control signal (Duty0) of the pressure control valve 13 for obtaining the target reference pressure (PCR0). Based on the difference between (PCR0) and the actual common rail pressure (PCR), the reference control signal (Duty0) is corrected, and the pressure control valve 13 is driven with the corrected control signal (Duty) to thereby achieve the target reference pressure (PCR0). Get.

  The drive control of the fuel injection valve 15 is first stored in advance in the ROM of the engine control unit 30 using, for example, the fuel injection amount Qmain (average or for each cylinder of # 1 to 4) and the common rail pressure (PCR) as parameters. The predetermined map is searched to obtain the fuel injection period (Mperiod: average or every cylinder of # 1 to # 4). The fuel injection period (Mperiod) becomes shorter as the common rail pressure PCR is the same if the fuel injection amount Qmain is the same, and becomes longer as the fuel injection amount Qmain is increased if the common rail pressure (PCR) is the same. Next, based on the signal from the crank angle sensor 32 for detecting the crank angle (engine speed and crank angle detection Ne) and the signal from the cylinder discrimination cam angle sensor 33 (cylinder discrimination signal Cyl), the fuel injection start timing (ITmain) Then, the fuel injection valve 15 of the cylinder to be injected in the fuel injection period (Mperiod) is driven to open, and a desired fuel injection amount Qmain is supplied.

  FIG. 23 shows the engine speed Ne, the fuel injection amount Qmain and the fuel required for performing the cylinder control and the exhaust air / fuel ratio control for the catalyst regeneration (rich) combustion control of the LNT 21 in the above-mentioned step 1600 (FIG. 19). It is a flowchart which shows the subroutine for calculating the target value of injection timing ITmain.

  In the catalyst regeneration cylinder stop control target value calculation routine of FIG. 23, in step 1601, it is determined whether the engine sharing output Pe is below a predetermined output Pe1.

  If No in step 1601 and the engine sharing output Pe is equal to or greater than the predetermined output Pe1, the process proceeds to step 1670.

  In step 1670, predetermined table data is retrieved, and target values for the rotational speed Ne, the main fuel injection amount Qmain, and the fuel injection timing ITmain for performing normal fuel injection control (the same control for each cylinder) are obtained.

  In the next step 1680, similarly, predetermined table data is searched, and a target value of the post fuel injection amount Qpost and its fuel injection timing ITpost for setting the exhaust air-fuel ratio to rich is obtained.

  In the next step 1690, a target value for normal EGR control (drive signals for the EGR valve 5 and the intake throttle valve 7) is obtained, and the process proceeds to step 1650.

  On the other hand, if Yes in step 1601 and the engine sharing output Pe is less than the predetermined output Pe1, the process proceeds to step 1610.

  In step 1610, the preset working cylinder and predetermined table data set for the working cylinder are retrieved, and the rotational speed Ne, the main fuel injection amount Qmain, and the fuel injection timing for performing the fuel injection control of the working cylinder. The target value of ITmain is obtained.

  In the next step 1620, similarly, predetermined table data is searched, and the post fuel injection amount Qpost and the target value of the fuel injection timing ITpost for setting the exhaust air-fuel ratio of the working cylinder to rich are obtained.

  In the next step 1630, a target value for EGR control of the working cylinder (drive signals for the EGR valve 5 and the intake throttle valve 7) is obtained.

  In the next step 1640, the operation of the predetermined cylinder is stopped, and the process proceeds to step 1650.

  In step 1650, the EGR valve 5 and the intake throttle valve 7 are drive-controlled based on the drive signal obtained in step 1630 or step 1690, and the process proceeds to step 1660.

  In Step 1660, based on the data obtained in Steps 1610 and 1620, or Steps 1670 and S1680, the common rail pressure control and the drive control of the fuel injection valve 15 are performed for the fuel injection control, that is, the engine output control, and a return is obtained. .

  Incidentally, the cylinder control and the exhaust air / fuel ratio control for the catalyst regeneration (rich) combustion control of the LNT 21 are performed in order to keep the exhaust temperature Tex at or above the first predetermined temperature Tex1 that is the catalyst activation temperature. As shown, the highest purification efficiency can be obtained when the temperature range for enriching the exhaust air-fuel ratio is set to a range of about 250 to 450 ° C. Therefore, as shown in FIGS. 6 and 8, the cylinder control is performed in a load range slightly higher than the engine output lower limit value b point to b point, and in the case of a four cylinder engine, only one cylinder is stopped. Further, the load range to be enriched is limited to a range where the temperature is not too high (for example, engine output b to c points).

  FIG. 24 shows the engine speed Ne, the fuel injection amount Qmain, and the fuel injection amount Qmain required for performing cylinder control and exhaust air / fuel ratio control for poisoning release (stoichiometric) combustion control of the LNT 21 in the above-described step 1700 (FIG. 19). It is a flowchart which shows the subroutine for calculating the target value of fuel-injection time ITmain.

  In the poisoning cancellation cylinder stop control target value calculation routine of FIG. 24, in step 1701, it is determined whether the engine sharing output Pe is lower than Pe2 which is higher than the predetermined output Pe1.

  If No in step 1701 and Pe2 or more, the process proceeds to step 1810.

  In step 1810, predetermined table data is retrieved, and target values for the rotational speed Ne, the main fuel injection amount Qmain, and the fuel injection timing ITmain for performing normal fuel injection control (the same control for each cylinder) are obtained.

  In the next step 1820, similarly, predetermined table data is searched, and the post fuel injection amount Qpost and the target value of the fuel injection timing ITpost for setting the exhaust air-fuel ratio to stoichiometric are obtained.

  In the next step 1830, a target value for normal EGR control (drive signals for the EGR valve 5 and the intake throttle valve 7) is obtained, and the process proceeds to step 1750.

  If YES in step 1701, the process proceeds to step 1702, and it is determined whether the engine sharing output Pe is below a predetermined output Pe1.

  If Yes in step 1702 and below the predetermined output Pe1 (in the case of low load), the process proceeds to step 1710.

  In step 1710, the operating cylinder previously set as pattern 1 (for example, two cylinders stopped) and the predetermined table data set for the operating cylinder are searched, and the rotational speed Ne for performing the fuel injection control of the operating cylinder, Target values for the main fuel injection amount Qmain and the fuel injection timing ITmain are obtained.

  In the next step 1720, similarly, predetermined table data is retrieved, and a post fuel injection amount Qpost for setting the exhaust air-fuel ratio of the working cylinder to stoichiometric and a target value of the fuel injection timing ITpost are obtained.

  In the next step 1730, a target value for EGR control of the working cylinder (drive signals for the EGR valve 5 and the intake throttle valve 7) is obtained.

  In the next step 1740, the operation of the predetermined cylinder is stopped and the process proceeds to step 1750.

  If No in step 1702 and the engine sharing output is intermediate between Pe1 and Pe2 (medium load), the process proceeds to step 1910.

  In step 1910, the working cylinder set in advance as pattern 2 (for example, one cylinder is stopped) and predetermined table data set for the working cylinder are searched, and the rotational speed Ne for carrying out the fuel injection control of the working cylinder, Target values for the main fuel injection amount Qmain and the fuel injection timing ITmain are obtained.

  In the next step 1920, predetermined table data is similarly searched to obtain a post fuel injection amount Qpost and a target value for the fuel injection timing ITpost for setting the exhaust air / fuel ratio of the working cylinder to stoichiometric.

  In the next step 1930, a target value for EGR control of the working cylinder (drive signals for the EGR valve 5 and the intake throttle valve 7) is obtained.

  In the next step 1740, the operation of the predetermined cylinder is stopped and the process proceeds to step 1750.

  In step 1750, the EGR valve 5 and the intake throttle valve 7 are drive-controlled based on the drive signal obtained in step 1730, step 1830 or step 1930, and the process proceeds to step 1760.

  In step 1760, based on the data obtained in steps 1710 and 1720, steps 1810 and 1820, or steps 1910 and 1920, common rail pressure control and drive control of the fuel injection valve 15 are performed for engine output control. And return.

  By the way, in the cylinder control and the exhaust air / fuel ratio control for the catalyst poisoning release (stoichiometric) combustion control of the LNT 21, as shown in FIG. 9, the temperature range in which the exhaust air / fuel ratio is stoichiometrically kept Tex at about 600 ° C. When set to, the highest poisoning release efficiency can be obtained. For this reason, as shown in FIG. 6 and FIG. 8, the cylinder control is performed in a load range slightly higher than the engine output lower limit b point to c point, and in the case of a 4-cylinder engine, the low load range is stopped by 2 cylinders. The load range (high load side) is set to stop one cylinder.

  Each cylinder output Pe during all cylinder operation and each cylinder output Pe ′ during cylinder stop operation have the following relationship (in the case of four cylinders).

During all cylinder operation: Pe '= Pe
Single cylinder stop operation: Pe ′ = 4 × Pe ÷ 3
2-cylinder stop operation: Pe ′ = 4 × Pe / 2
That is, the output of each working cylinder is determined so that the sum of the outputs of each working cylinder during cylinder stop operation is equal to the sum of the outputs of each cylinder during all cylinder operation (4 × Pe).

  As described above, the present invention relates to an exhaust purification catalyst provided in an exhaust passage of an internal combustion engine, and a catalyst demand detection means for detecting a demand for an exhaust temperature or an exhaust air-fuel ratio based on the state of the exhaust purification catalyst. The required output calculation means for calculating the output required for the internal combustion engine, and the inflow and outflow of gas and the fuel supply in each cylinder of the internal combustion engine are stopped, so that some cylinders can be stopped and exhaust purification Cylinder control means for determining and controlling the number of stopped cylinders and the output of the working cylinder according to the request and the required output of the internal combustion engine when the exhaust temperature or the exhaust air / fuel ratio is requested based on the state of the catalyst for the engine And an exhaust air / fuel ratio control means for controlling the air / fuel ratio of the exhaust gas discharged from the working cylinder and flowing into the exhaust gas purification catalyst, so that it is necessary to increase the exhaust temperature based on the state of the exhaust gas purification catalyst. At the time of exhaust gas / fuel ratio enrichment request, cylinder control that stops gas inflow and fuel supply and fuel supply of some cylinders provides the required exhaust temperature and exhaust air / fuel ratio without increasing the output of the internal combustion engine. Therefore, it is possible to improve the purification performance without eliminating wasteful energy consumption and reducing the efficiency.

  In particular, in a hybrid vehicle, a catalyst request detection unit that detects a request for an exhaust temperature or an exhaust air-fuel ratio based on a state of an exhaust purification catalyst, a required driving force calculation unit that calculates a driving force required for traveling of the vehicle, Battery remaining amount detecting means for detecting the remaining amount of the battery; requested output calculating means for calculating a required output together with determination of necessity of operation of the internal combustion engine based on the required driving force and the remaining battery capacity; By stopping gas inflow and outflow and fuel supply in each cylinder of the engine, some cylinders can be stopped, and it is determined that the operation of the internal combustion engine is necessary. Cylinder control means for determining and controlling the number of stopped cylinders and the output of the working cylinder according to the request and the required output of the internal combustion engine when the exhaust temperature or the exhaust air-fuel ratio is based on And an exhaust air / fuel ratio control means for controlling the air / fuel ratio of the exhaust gas discharged from the working cylinder and flowing into the exhaust gas purification catalyst. It can be prevented and a decrease in energy efficiency can be suppressed.

  Further, the cylinder control means can be controlled more favorably by reducing the number of stopped cylinders as the required output of the internal combustion engine increases.

  Further, when a NOx trap catalyst is used as the exhaust gas purification catalyst, the catalyst demand detection means needs to increase the exhaust gas temperature to increase the activity of the NOx trap catalyst (warming-up promotion demand). And a catalyst regeneration request that requires NOx adsorbed on the NOx trap catalyst to be enriched by exhaust gas air-fuel ratio, and a sulfur content deposited on the NOx trap catalyst to be detoxified by raising the exhaust temperature. By adopting a configuration that detects at least one of the poisoning release requests having the above, it is possible to obtain the necessary exhaust temperature and exhaust air-fuel ratio at the time of these requests, respectively.

  Further, the cylinder control means increases the number of stopped cylinders at the time of the poisoning release request than at the time of the catalyst activity enhancement request or the catalyst regeneration request even when the required output of the internal combustion engine is constant. Therefore, it is possible to meet the strict requirements at the time of the poisoning release request.

  Further, the exhaust air / fuel ratio control means is configured such that when the catalyst activity enhancement request is made, the exhaust of the working cylinder at the time of cylinder control is performed even if the load of the working cylinder at the time of cylinder control is the same as the cylinder load at the time of normal operation. The air-fuel ratio is controlled to decrease within a lean range with respect to the exhaust air-fuel ratio during normal operation.When the catalyst regeneration is requested, the exhaust air-fuel ratio of the working cylinder is controlled to be rich, and when the poisoning release request is requested By adopting a configuration in which the exhaust air / fuel ratio of the working cylinder is controlled to be stoichiometric, an exhaust air / fuel ratio suitable for each can be obtained.

  In addition, when performing control to stop some of the cylinders by the cylinder control means, stable control is possible by keeping the exhaust air-fuel ratio and load (output) constant between the operating cylinders.

  In addition, the exhaust air-fuel ratio control means includes a post-injection performed in an expansion stroke or an exhaust stroke after the main injection of fuel for generating an output to the working cylinder of the internal combustion engine, an intake throttle strengthening, an EGR strengthening, By performing at least one, it is possible to reliably control the exhaust air-fuel ratio that is discharged from the working cylinder of the internal combustion engine and flows into the exhaust purification catalyst.

1 is a system configuration diagram showing an embodiment of an engine exhaust gas purification control apparatus according to the present invention. Characteristics chart of various energization controls to prepare for starting when the engine is stopped The figure which shows the relationship between battery remaining charge (SOC), electric power processing mode, etc. Characteristics of normal driving force control Characteristics diagram of driving force control for remaining charge adjustment The figure which shows the cylinder stop control pattern for NOx reproduction | regeneration The figure which shows the cylinder stop control pattern for S poison cancellation | release The figure which shows the cylinder stop control pattern for NOx reproduction | regeneration and S poisoning cancellation | release Operating region characteristics Flow chart of basic control routine of hybrid system Flow chart of required driving force calculation routine Normal operation mode determination routine flowchart Flow chart of shared output calculation routine in normal operation mode Flow chart of engine start time control routine Flow chart of block heater energization control routine EHC energization control routine flowchart Flow chart of glow plug energization control routine Flow chart of engine stop control routine Flow chart of engine output control routine Flowchart of surplus power processing operation mode determination routine Flow chart of shared output calculation routine in surplus power processing operation mode Flow chart of target value calculation routine for lean combustion control Flow chart of target value calculation routine for cylinder stop control during catalyst regeneration S Flow chart of target value calculation routine for cylinder stop control at the time of release of poisoning

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Intake passage 2a Air cleaner 2b Supercharger compressor 2c Intercooler 2d Intake pipe 3 Exhaust passage 3a Turbocharger turbine 4 EGR passage 5 EGR valve 6 Intake shut-off valve 7 Intake throttle valve 10 Fuel injection device 11 Supply pump 12 Fuel supply passage 13 Pressure control valve 14 Common rail (accumulation chamber)
15 Fuel injection valve 16 Fuel supply passage 17 Overflow passage 18 One-way valve 19 Fuel return passage 20 Exhaust purification post-treatment device 21 NOx trap catalyst (LNT; EHC configuration)
24 Glow plug 30 Engine control unit 31 Water temperature sensor 32 Crank angle sensor 33 Cam angle sensor 34 Pressure sensor 35 Temperature sensor 36 Oxygen concentration sensor 40 Hybrid control unit 41 Accelerator sensor 42 Start key 43 Shift lever position sensor 44 Brake operation switch 45 Vehicle speed sensor 46 Battery remaining amount sensor 50 Battery 51 Motor generator (MG1)
52 Power transmission mechanism 53 Motor generator (MG2)
54 Differential gear 55a, 55b Drive wheel 60 Fuel tank 70 Block heater

Claims (8)

An exhaust purification catalyst provided in the exhaust passage of the internal combustion engine;
Catalyst request detecting means for detecting a request for exhaust temperature or exhaust air-fuel ratio based on the state of the exhaust purification catalyst;
Requested output calculating means for calculating an output required for the internal combustion engine;
By stopping the inflow and outflow of gas and fuel supply in each cylinder of the internal combustion engine, some cylinders can be stopped, and when the exhaust temperature or exhaust air-fuel ratio is requested based on the state of the exhaust purification catalyst, Cylinder control means for determining and controlling the number of stopped cylinders and the output of the working cylinder according to the request and the required output of the internal combustion engine;
Exhaust air-fuel ratio control means for controlling the air-fuel ratio of exhaust exhausted from the working cylinder and flowing into the exhaust purification catalyst;
An exhaust gas purification control device for an internal combustion engine comprising: An internal combustion engine, a motor generator that also serves as a generator, and a battery that can supply power to the motor generator and charge the generated power of the motor generator. The output of at least one of the internal combustion engine and the motor generator In a hybrid vehicle that drives a vehicle by generating a driving force,
An exhaust purification catalyst provided in the exhaust passage of the internal combustion engine;
Catalyst demand detection means for detecting a demand for exhaust temperature or exhaust air-fuel ratio based on the state of the exhaust purification catalyst;
A required driving force calculating means for calculating a driving force required for traveling of the vehicle;
Battery remaining amount detecting means for detecting the remaining amount of the battery;
Based on the required driving force and the remaining battery level, a required output calculating means for calculating a required output together with a determination as to whether or not to operate the internal combustion engine;
By stopping the inflow and outflow of gas and the fuel supply in each cylinder of the internal combustion engine, some cylinders can be stopped, and it is determined that the operation of the internal combustion engine is necessary. Cylinder control means for determining and controlling the number of stopped cylinders and the output of the working cylinder according to the request and the required output of the internal combustion engine when requesting the exhaust temperature or the exhaust air-fuel ratio based on the state;
Exhaust air-fuel ratio control means for controlling the air-fuel ratio of exhaust exhausted from the working cylinder and flowing into the exhaust purification catalyst;
An exhaust gas purification control device for an internal combustion engine comprising:   The exhaust gas purification control apparatus for an internal combustion engine according to claim 1 or 2, wherein the cylinder control means decreases the number of stopped cylinders as the required output of the internal combustion engine increases. The exhaust purification catalyst is a NOx trap catalyst that adsorbs NOx in the exhaust when the exhaust air-fuel ratio is lean, and desorbs and purifies the adsorbed NOx when the exhaust air-fuel ratio is rich,
The catalyst request detection means includes
A catalyst activity enhancement request that requires raising the exhaust temperature to increase the activity of the NOx trap catalyst;
A catalyst regeneration request that requires the exhaust air / fuel ratio to be enriched to desorb and purify NOx adsorbed on the NOx trap catalyst;
Among the poisoning release requests that require the sulfur content accumulated on the NOx trap catalyst to be poisoned by raising the exhaust temperature,
The exhaust gas purification control apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein at least one is detected.   The cylinder control means increases the number of stopped cylinders at the time of the poisoning release request than at the time of the catalyst activity enhancement request or at the time of the catalyst regeneration request, even if the required output of the internal combustion engine is constant. The exhaust gas purification control apparatus for an internal combustion engine according to claim 4. The exhaust air-fuel ratio control means includes
When the catalyst activity enhancement request is made, the exhaust air / fuel ratio of the working cylinder at the time of cylinder control is set to the exhaust air / fuel ratio at the time of normal operation even if the load of the working cylinder at the time of cylinder control is the same as the cylinder load at the time of normal operation. Against the range of lean,
When the catalyst regeneration request is made, the exhaust air-fuel ratio of the working cylinder is controlled to be rich,
6. The exhaust gas purification control apparatus for an internal combustion engine according to claim 4, wherein the exhaust air-fuel ratio of the working cylinder is stoichiometrically controlled when the poisoning release request is made.   The exhaust air-fuel ratio and the load are kept constant between the operating cylinders when the control for stopping some of the cylinders is performed by the cylinder control means. An exhaust gas purification control device for an internal combustion engine as described.   The exhaust air / fuel ratio control means has at least one of post injection, intake throttle strengthening, and EGR strengthening performed in an expansion stroke or an exhaust stroke after the main injection of fuel for generating output to the working cylinder of the internal combustion engine. The internal combustion engine according to any one of claims 1 to 7, wherein the exhaust air-fuel ratio discharged from the working cylinder of the internal combustion engine and flowing into the exhaust purification catalyst is controlled by performing Exhaust purification control device.

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