JP2022088262A - Controller of internal combustion engine - Google Patents

Abstract

To further reduce a discharge amount of harmful matters HC right after start of an internal combustion engine.SOLUTION: An internal combustion engine is configured such that a purification device having an adsorption layer that adsorbs HC contained in exhaust discharged from a cylinder and a catalyst layer that oxidizes HC is provided in an exhaust passage. Immediately after the start of the internal combustion engine, an amount of air suctioned into the cylinder is controlled to be smaller and ignition timing is made more retarded, and the temperature rise of the adsorption layer is delayed from the temperature rise of the catalyst layer due to the difference in heat capacity between the adsorption layer and the catalyst layer.SELECTED DRAWING: Figure 6

Description

The present invention relates to an internal combustion engine mounted as a power source in a vehicle or the like.

The combustion gas discharged from the cylinder of the internal combustion engine contains harmful substances such as hydrocarbon HC, carbon monoxide CO and nitrogen oxide NO _x . In general, the exhaust passage of an internal combustion engine is equipped with an exhaust purification device having a three-way catalyst that oxidizes / reduces these HC, CO, and NO _x to make them harmless.

In order to sufficiently purify harmful substances in a three-way catalyst, it is necessary that the temperature rises to several hundred degrees Celsius or higher and the catalyst is activated. Immediately after starting the internal combustion engine that had been stopped, the temperature of the catalyst of the exhaust gas purification device has also dropped, so it is not possible to sufficiently purify harmful substances. In particular, there is a concern that a large amount of HC will be emitted.

Therefore, the exhaust gas purification device is provided with an HC adsorption layer coated with zeolite or the like (see, for example, the following patent document). The presence of the adsorption layer makes it possible to adsorb HC generated before the catalyst is heated and activated, and to temporarily hold the HC so that it is not discharged as it is.

However, the temperature at which the adsorption layer can adsorb HC is lower than the temperature at which the three-way catalyst is activated. When the temperature of the adsorption layer rises to 100 ° C. to 150 ° C. or higher, the HC once adsorbed on the adsorption layer is desorbed from the adsorption layer. On the other hand, since the catalyst has not been activated yet, the HC cannot be sufficiently oxidized, and the HC is temporarily released to the outside.

Japanese Unexamined Patent Publication No. 2020-084832

An object of the present invention is to further reduce the amount of harmful substance HC emitted immediately after the start of an internal combustion engine.

In order to solve the above-mentioned problems, in the present invention, the internal combustion engine is provided with a purification device having an adsorption layer for adsorbing HC contained in the exhaust discharged from the cylinder and a catalyst layer for oxidizing HC in the exhaust passage. Therefore, in the period immediately after the start of the internal combustion engine, the amount of air sucked into the cylinder is controlled to be smaller and the ignition timing is further retarded as compared with other periods, and the adsorption layer and the catalyst layer are controlled. An internal combustion engine was constructed in which the temperature rise of the adsorption layer was delayed from the temperature rise of the catalyst layer due to the difference in the heat capacity of the catalyst layer.

Further, in the present invention, the internal combustion engine is provided with a purification device having an adsorption layer for adsorbing HC contained in the exhaust gas discharged from the cylinder and a catalyst layer for oxidizing HC in the exhaust passage. At a time when the temperature of the adsorption layer after starting is considered to be above a certain value, the amount of air sucked into the cylinder is larger and the ignition timing is controlled to be more retarded as compared with other times. An internal combustion engine was constructed in which the temperature rise of the catalyst layer was promoted.

According to the present invention, it is possible to further reduce the amount of harmful substance HC emitted immediately after the start of the internal combustion engine.

The figure which shows the schematic structure of the series type hybrid vehicle and the control device which carries out the internal combustion engine which concerns on this invention. The figure which shows the structure of the internal combustion engine mounted on the hybrid vehicle. The cross-sectional view which shows the part of the exhaust gas purification device of the internal combustion engine enlarged. The cross-sectional view which shows the part of the exhaust gas purification device of the internal combustion engine enlarged. The figure which shows the procedure example of the process which the control device of the internal combustion engine of 1st Embodiment of this invention executes according to a program. The figure which illustrates the transition of the temperature rise of each of the catalyst layer and the adsorption layer of the exhaust gas purification device of the internal combustion engine of the same embodiment. The figure which shows the procedure example of the process which the control device of the internal combustion engine of 1st Embodiment of this invention executes according to a program. The figure which illustrates the transition of the temperature rise of each of the catalyst layer and the adsorption layer of the exhaust gas purification device of the internal combustion engine of the same embodiment. The figure which exemplifies the transition of the temperature rise of each of the catalyst layer and the adsorption layer of the exhaust gas purification device of the conventional internal combustion engine.

<First Embodiment> An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a main system of a hybrid vehicle according to the present embodiment. This hybrid vehicle includes an internal combustion engine 1, a power generation motor generator 2 driven by the internal combustion engine 1 to generate electricity, a power storage device 3 for storing the electric power generated by the power generation motor generator 2, a power generation motor generator 2 and /. Alternatively, it includes a traveling motor generator 4 that drives the drive wheels 62 of the vehicle by receiving electric power from the power storage device 3.

The hybrid vehicle of the present embodiment is a series hybrid type electric vehicle in which the internal combustion engine 1 is used only for power generation, and the driving force for traveling is supplied exclusively to the driving wheels 62 of the vehicle from the traveling motor generator 4. The internal combustion engine 1 and the drive wheel 62 are mechanically separated from each other, and the rotational driving force is not originally transmitted between the two. Therefore, the internal combustion engine 1 can rotate completely independently of the traveling motor generator 4 and the drive wheels 62, and can be stopped completely independently. Therefore, the power storage device 3 is sufficient even when the vehicle can be driven by the driver depressing the accelerator pedal during the operation of the vehicle in which the ignition switch (power switch or ignition key) is operated to be ON. Under the condition that the charge is stored and the brake booster 15 stores a sufficient negative pressure, the operation of the internal combustion engine 1 accompanied by the combustion of fuel may not be performed.

The crankshaft, which is the rotating shaft of the internal combustion engine 1, is mechanically connected to the rotating shaft of the power generation motor generator 2 via a gear mechanism or directly connected to the shaft. Then, by inputting the rotational driving force output by the internal combustion engine 1 to the power generation motor generator 2, the power generation motor generator 2 generates power. The generated electric power charges the power storage device 3 and / or supplies it to the traveling motor generator 4. Further, the power generation motor generator 2 also functions as a motoring motor that generates a rotational driving force by itself to rotationally drive the crankshaft of the internal combustion engine 1. For example, the power generation motor generator 2 executes cranking in preparation for starting the stopped internal combustion engine 1.

The traveling motor generator 4 generates a driving force for traveling the vehicle, and inputs the driving force to the drive wheels 62 via the speed reducer 61. Further, the traveling motor generator 4 is rotated by being rotated by the drive wheels 62 to generate electricity, and recovers the kinetic energy of the vehicle as electric energy. The electric power generated by this regenerative braking charges the power storage device 3.

However, if the charge is already stored up to the full capacity of the power storage device 3 and it is difficult to charge the battery any more, the traveling motor generator 4 dares to supply the regenerated electric power to the power generation motor generator 2 to generate electricity. The motor generator 2 is operated as an electric motor to rotate and drive the internal combustion engine 1. As a result, the surplus electric power is exhausted while maintaining the braking performance of the vehicle. Further, at this time, since the rotation of the internal combustion engine 1 is maintained, it is possible to execute a fuel cut that temporarily stops the fuel supply to the cylinder of the internal combustion engine 1.

The generator inverter 21 converts the AC power generated by the power generation motor generator 2 into DC power. Then, the DC power is input to the power storage device 3 or the drive unit inverter 41. Further, the generator inverter 21 converts the DC power supplied from the power storage device 3 and / or the drive inverter 41 into AC power when the power generation motor generator 2 is operated as an electric motor, and then the power generation motor generator 2. Enter in.

The drive inverter 41 converts the DC power supplied from the power storage device 3 and / or the generator inverter 21 into AC power, and then inputs the DC power to the traveling motor generator 4. Further, the drive inverter 41 converts the AC power generated by the traveling motor generator 4 into DC power when performing regenerative braking of the vehicle, and then inputs the AC power to the power storage device 3 or the generator inverter 21. The generator inverter 21 and the drive inverter 41 form a part of the PCU (Power Control Unit) 02.

The power storage device 3 is a battery and / or a capacitor or the like. The battery is a high-voltage secondary battery having a high energy density, such as a lithium ion secondary battery or a nickel-hydrogen secondary battery. The power storage device 3 charges and stores the electric power generated by each of the power generation motor generator 2 and the traveling motor generator 4. Further, the power storage device 3 discharges electric power for operating each of the power generation motor generator 2 and the traveling motor generator 4 as an electric motor, and supplies the electric power required for the motor generators 2 and 4.

FIG. 2 schematically shows the structure of the internal combustion engine 1 mounted on the vehicle. The internal combustion engine 1 is, for example, a spark-ignition 4-stroke gasoline engine, and includes a plurality of cylinders 11 (one of which is illustrated in FIG. 2). An injector 111 that injects fuel toward the intake port is provided in the vicinity of the intake port of each cylinder 11. Further, a spark plug 112 is attached to the ceiling of the combustion chamber of each cylinder 11. The spark plug 112 induces a spark discharge between the center electrode and the ground electrode in response to the application of the induced voltage generated by the ignition coil.

The intake passage 13 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 11. An air cleaner 131, an electronic throttle valve 132, a surge tank 133, and an intake manifold 134 are arranged in this order from the upstream on the intake passage 13.

The exhaust passage 14 for exhausting the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 11 to the outside from the exhaust port of each cylinder 11. An exhaust manifold 142 and an exhaust purification device 141 are arranged on the exhaust passage 14. The exhaust purification device 141 includes a three-way catalyst layer 1411 that oxidizes / reduces harmful substances HC, CO, and NO _x contained in the exhaust gas discharged from the cylinder 1 of the internal combustion engine 1 to make them harmless, and among the harmful substances. In particular, it is provided with an HC adsorption layer 1412 that adsorbs HC. The catalyst layer 1411 is formed by applying a coating material containing platinum Pt, which is a noble metal acting as a three-way catalyst, and ceria CeO ₂ , which has an oxygen storage capacity, to a carrier 1413 having a honeycomb structure made of ceramic such as cordylite. can. The adsorption layer 1412 can be configured by applying an adsorbent such as zeolite capable of adsorbing HC to the carrier 1413.

As shown in FIG. 3, in the exhaust gas purification device 141, the adsorption layer 1412 is formed on the surface of the carrier 1413, and the catalyst layer 1411 is formed on the adsorption layer 1412. However, as shown in FIG. 4, the adsorption layer 1412 may be separately formed on the upstream side and the catalyst layer 1411 may be separately formed on the downstream side along the direction in which the exhaust gas flows in the exhaust gas purification device 141.

The external EGR (Exhaust Gas Recirculation) device 12 opens and closes the external EGR passage 121 that connects the exhaust passage 14 and the intake passage 13, the EGR cooler 122 provided on the EGR passage 121, and the EGR passage 121, and the EGR passage 121. The element is an EGR valve 123 that controls the flow rate of the EGR gas flowing through the EGR gas. The inlet of the EGR passage 121 is connected to a predetermined position downstream of the catalyst 141 in the exhaust passage 14. The outlet of the EGR passage 121 is connected to a predetermined position downstream of the throttle valve 132 in the intake passage 13 (particularly, a surge tank 133 or an intake manifold 134).

The internal combustion engine 1 is provided with a brake booster 15 for reducing the operating force required when braking the vehicle, that is, the pedaling force of the brake pedal. The brake booster 15 draws an intake negative pressure from a portion of the intake passage 13 on the downstream side of the throttle valve 132, and uses the negative pressure to boost the pedaling force of the brake pedal, which is widely known in this field. It is a force type (vacuum type).

The ECU (Electronic Control Unit) 0, which is a control device that controls the internal combustion engine 1, the power generation motor generator 2, the power storage device 3, the inverters 21, 41, and the traveling motor generator 4, is a processor, a memory, an input interface, an output interface, and the like. It is a microcomputer system having. The ECU 0 is a plurality of ECUs, that is, an EFI (Electronic Fuel Injection) ECU 01 that controls an internal combustion engine 1, an MG (Motor Generator) ECU 02 that controls motor generators 2, 4 and inverters 21, 41, and a BMS that controls a power storage device 3. (Battery Management System) ECU 03 and the like, and HV (Hybrid Vehicle) ECU 00, which is a higher-level controller that controls their control, are connected to each other so as to be able to communicate with each other via a telecommunications line such as CAN (Control Area Network). It is a vehicle.

For ECU 0, the vehicle speed signal a output from the vehicle speed sensor that detects the actual vehicle speed of the vehicle, the crank angle signal b output from the crank angle sensor that detects the rotation angle of the crank shaft of the internal combustion engine 1 and the engine rotation speed. , The accelerator opening signal output from the sensor that detects the amount of depression of the accelerator pedal by the driver as the accelerator opening (so to speak, the driving force required by the driver for the vehicle (driving motor generator 4)). c, a switch that detects that the driver is stepping on the brake pedal, a sensor that detects the amount of depression of the brake pedal by the driver, or a sensor that detects the master cylinder pressure, which is the pressure of the brake liquid discharged from the master cylinder 16. It is output from the brake depression signal d output from the temperature / pressure sensor that detects the intake air temperature and the intake air pressure in the intake passage 13 (particularly, the surge tank 133 or the intake manifold 134) connected to the cylinder 11 of the internal combustion engine 1. The intake air temperature / intake pressure signal e, the cooling water temperature signal f output from the water temperature sensor that detects the temperature of the cooling water of the internal combustion engine 1, and the sensor that detects the amount of charge stored in the power storage device 3 (particularly, the battery current and / Alternatively, the battery SOC (State Of Charge) signal g output from the battery voltage sensor), the negative pressure signal h output from the negative pressure sensor for detecting the negative pressure stored in the constant pressure chamber of the brake booster 15, and the like are input. ..

Then, the ECU 0 determines the amount of depression of the accelerator pedal operated by the driver, the current vehicle speed, the amount of electric charge stored in the power storage device 3, and the power generation motor generator 2, which are sensed via various sensors. The magnitude of the rotational driving force output by the traveling motor generator 4, the rotational driving force output by the internal combustion engine 1, and the electric charge generated by the power generation motor generator 2 is controlled according to the generated electric power and the like.

As a general rule, if the power storage device 3 currently stores sufficient electric charge and the output required for the traveling motor generator 4 is small, the supply of fuel to the internal combustion engine 1 is cut off and the internal combustion engine 1 is operated. do not do. On the other hand, if the amount of electric charge stored in the power storage device 3 is below the lower limit or the output required for the traveling motor generator 4 is large, the internal combustion engine 1 is started to supply fuel to the cylinder 11. It executes firing to burn it, drives the generator motor generator 2 by the rotational driving force output by the internal combustion engine 1, generates electricity to charge the power storage device 3, or supplies it to the traveling motor generator 4. Increase the power to be generated.

In order to start the internal combustion engine 1 and execute power generation by the power generation motor generator 2, first, the power generation motor generator 2 is operated as an electric motor, thereby motoring for starting the internal combustion engine 1. Ranking). When the crankshaft of the internal combustion engine 1 has rotated a predetermined number of times or more or a predetermined angle or more, and the cylinder determination for knowing the current stroke of each cylinder 11 of the internal combustion engine 1 or the position of the piston is completed, each cylinder 11 of the internal combustion engine 1 is completed. Inject fuel at an appropriate timing according to the process of, and start firing to ignite and burn the fuel at an appropriate timing. The rotation angle and rotation speed of the crankshaft of the internal combustion engine 1, that is, the engine speed can be detected via the resolver attached to the power generation motor generator 2 (in the MG ECU 02), and the crank angle sensor attached to the internal combustion engine 1 can be detected. It can also be detected via (in the EFI ECU 01).

When the rotation of the crank shaft of the internal combustion engine 1 accelerates and the engine rotation speed exceeds the start determination value, the internal combustion engine 1 starts and is in a state of autonomous rotation (in other words, a motor generator for power generation). Even if the output of 2 is reduced, the engine rotation speed can still maintain the upward trend), and the output of the power generation motor generator 2 operating as an electric motor is reduced to 0 to end the motoring. do.

After the start determination of the internal combustion engine 1, the internal combustion engine 1 rotationally drives the power generation motor generator 2. Then, the power generation motor generator 2 is operated as a generator, and the generated power is increased from 0. Then, the intake amount and the fuel injection amount supplied to the cylinder 1 of the internal combustion engine 1 and the power generation power of the power generation motor generator 2 are adjusted in an increase or decrease so as to follow the target rotation speed in which the engine rotation speed is gradually increased. .. The final target rotation speed is the rotation speed at which the internal combustion engine 1 can be operated with optimum or near optimum efficiency and is most advantageous for the fuel consumption rate, or the internal combustion engine 1 has the maximum torque or maximum output or a torque or output close to this. Set the number of revolutions so that it can be achieved.

The EFI ECU 01, which forms a part of the ECU 0, acquires various information a, b, c, d, e, f, g, h necessary for the operation control of the internal combustion engine 1 via the input interface, and knows the engine rotation speed. The required fuel injection amount and fuel injection (necessary to achieve the target air-fuel ratio) commensurate with the intake air amount are estimated by estimating the amount of air sucked into the cylinder 11 (so to speak, engine torque or engine load factor). Operating parameters of the internal combustion engine 1 such as timing (including the number of fuel injections for one combustion), fuel injection pressure, ignition timing (including the number of ignitions for one combustion), required EGR rate (or EGR gas amount), etc. To determine. The EFI ECU 01 ignites various control signals such as an ignition signal i, a fuel injection signal j, an opening operation signal k of the throttle valve 132, and an opening operation signal l of the EGR valve 123 corresponding to the operation parameters via the output interface. It outputs to the igniter, injector 111, throttle valve 132, EGR valve 123, etc. of the plug 112.

Then, as shown in FIG. 5, the ECU 0 (or EFI ECU 01) of the present embodiment starts (determines) the internal combustion engine 1 whose firing has been stopped immediately after (step S1). , The amount of air and fuel injected into the cylinder 11 of the internal combustion engine 1 is smaller than that at other times, and the spark ignition timing of the air-fuel mixture in the cylinder 11 is controlled to be more retarded (). Step S2).

In step S2, for example, the target engine speed or idle speed is set lower than the normal value, and the opening degree of the throttle valve 132 is reduced from the normal value, so that the intake air amount and the fuel injection amount are set to be lower than the normal value. Reduce. The fuel injection amount at this time is set so that the air-fuel ratio of the air-fuel mixture filled in the cylinder 1 becomes the stoichiometric air-fuel ratio or a target air-fuel ratio in the vicinity thereof. Further, if the ignition timing is delayed from the normal angle, the thermomechanical conversion efficiency in the cylinder 11 is further lowered. By that amount, the temperature of the exhaust gas discharged from the cylinder 11 and flowing into the exhaust gas purification device 141 becomes higher.

In addition, in the present embodiment, a difference is provided between the heat capacity of the HC adsorption layer 1412 in the exhaust gas purification device 141 and the heat capacity of the three-way catalyst layer 1411. Specifically, the layer 1412 of the HC adsorbent to be applied to the carrier 1413 may be thicker (or larger) than the layer 1411 of the coating material containing the ternary catalyst, or the average pore diameter of the former layer 1412 may be increased. The heat capacity of the adsorption layer 1412 is made larger than the heat capacity of the catalyst layer 1411 by making it smaller than the average pore diameter of the latter layer 1411.

Assuming that the heat capacity of the adsorption layer 1412 and the heat capacity of the catalyst layer 1411 are equivalent, as shown in FIG. 9, the temperature of the adsorption layer 1412 after the start of the internal combustion engine 1 (drawn by a thick broken line in the figure). The rate of increase in temperature (the amount of temperature increase per unit time) and the rate of increase in the temperature of the catalyst layer 1411 (drawn by a thin solid line in the figure) become close to each other. The temperature T ₁ at which the catalyst layer 1411 is activated, that is, the temperature at which the harmful substances HC, CO, and NO _x contained in the exhaust gas can be oxidized / reduced to some extent or more by the three-way catalyst to be purified is several hundred degrees Celsius or more. .. On the other hand, the temperature T ₂ at which the adsorption layer 1412 separates the adsorbed HC is lower than that, and is about 100 ° C. to 150 ° C. Strictly speaking, in the adsorption layer 1412, the adsorption and desorption of HC proceed at the same time, and when the temperature of the adsorption layer 1412 rises to T ₂ or higher, the speed of desorption of HC (unit time and unit). The amount of desorption per area) exceeds the speed of adsorption (unit time and amount of adsorption per unit area). Therefore, during the period C from when the temperature of the HC adsorption layer 1412 reaches T ₂ to when the temperature of the three-way catalyst layer 1411 reaches T ₁ , the HC once adsorbed on the adsorption layer 1412 is desorbed from the adsorption layer 1412. Moreover, the HC is not sufficiently oxidized in the catalyst layer 1411 and is released to the outside.

On the other hand, if the heat capacity of the adsorption layer 1412 is larger than the heat capacity of the catalyst layer 1411, the temperature of the adsorption layer 1412 after the start of the internal combustion engine 1 (drawn by a thick broken line in the figure) as shown in FIG. ) Slowly rises, and the temperature of the catalyst layer 1411 (drawn by a thin solid line in the figure) rises faster. By controlling step S2 that retards the ignition timing while reducing the amount of intake air, the temperature of the HC adsorption layer 1412 reaches T ₂ in combination with the fact that the exhaust gas flowing through the exhaust gas purification device 141 becomes hot and has a small flow rate. The period A from when the temperature of the three-way catalyst layer 1411 reaches T ₁ is shortened. As a result, it becomes possible to reduce the amount of HC released to the outside immediately after the start of the internal combustion engine 1 as compared with the conventional case.

When the temperature of the three-way catalyst layer 1411 of the exhaust gas purification device 141 rises above the activation temperature T ₁ (step S3), the ECU 0 ends the control of step S2 and is sucked into the cylinder 11 of the internal combustion engine 1. The amount of air and the amount of fuel injected are increased to the normal amount, and the spark ignition timing of the air-fuel mixture in the cylinder 11 is advanced to the normal timing (step S4).

The ECU 0 repeatedly estimates the current floor temperature of the exhaust gas purification device 141 (or the temperature of the carrier 1413, the adsorption layer 1412, or the catalyst layer 1411) at predetermined intervals. In step S3, the estimated temperature is compared with the activation temperature T ₁ . The estimation of the current temperature of the exhaust gas purification device 141 can be performed according to a known method. Specifically, first, based on the current operating region of the internal combustion engine 1, the basic value of the temperature of the exhaust gas discharged from the cylinder 11 and flowing through the exhaust passage 14 is obtained. In the memory of ECU 0, the operating area of the internal combustion engine [engine rotation speed, engine torque (or engine load factor, throttle valve 132 opening, intake pressure in surge tank 133, intake air amount or fuel injection amount)] and exhaust gas are stored in advance. Map data that defines the relationship with the basic value of temperature is stored. The ECU 0 searches the map using the parameters of the current operating area as a key, and obtains the basic value of the exhaust temperature.

Then, the basic value of the exhaust temperature is corrected according to the current spark ignition timing, the air-fuel ratio of the air-fuel mixture, the outside air temperature, the vehicle speed, and the like. The exhaust temperature rises as the ignition timing retards, decreases as the air-fuel ratio deviates from the stoichiometric air-fuel ratio, and as the outside temperature decreases and the vehicle speed increases (the flow rate of the running wind blown into the engine room increases). (Because the exhaust passage 14 is more air-cooled), the temperature is lowered. Further, the heat of the exhaust gas flowing into the exhaust gas purification device 141 is transferred to the exhaust gas purification device 141 (carrier 1413, adsorption layer 1412 or catalyst layer 1411), and the time required to raise the temperature is added to the exhaust gas purification device. Calculate the current estimated temperature of 141.

The current temperature of the exhaust gas purification device 141 is estimated according to the cumulative intake air amount or fuel injection amount since the internal combustion engine 1 is started and the firing is started, the cumulative crankshaft rotation speed, or the elapsed time. It is also possible to do. Of course, if a sensor for detecting the temperature of the exhaust purification device 141 is installed, the ECU 0 can directly measure the current temperature of the exhaust purification device 141 with reference to the output signal of the temperature sensor. In step S3, the measured temperature may be compared with the activation temperature T ₁ .

In the present embodiment, the internal combustion engine 1 is provided with a purification device 141 having an adsorption layer 1412 for adsorbing HC contained in the exhaust discharged from the cylinder 11 and a catalyst layer 1411 for oxidizing HC in the exhaust passage 14. Immediately after the start of the internal combustion engine 1, the amount of air sucked into the cylinder 11 is controlled to be smaller and the ignition timing is further retarded as compared with other times, and the adsorption layer 1412 and the catalyst are controlled. An internal combustion engine was configured in which the temperature rise of the adsorption layer 1412 was delayed from the temperature rise of the catalyst layer 1411 due to the difference in heat capacity from the layer 1411. According to the present embodiment, immediately after the start of the internal combustion engine 1, the amount of HC desorbed from the adsorption layer 1412 that is not purified by the catalyst layer 1411 and is released to the outside can be further reduced.

<Second Embodiment> The second embodiment of the present invention is a partially modified version of the above-mentioned first embodiment. Hereinafter, the differences from the first embodiment will be mainly described. The description of the elements common to the first embodiment, such as the outline of the hybrid vehicle, the internal combustion engine 1, the exhaust gas purification device 141, and the like, will be omitted.

As shown in FIG. 7, the ECU 0 (or EFI ECU 01) of the present embodiment starts (determines) the internal combustion engine 1 whose firing has been stopped (determined), and then sucks the exhaust gas purification device 141 (step S1). The amount of air sucked into the cylinder 11 of the internal combustion engine 1 and the amount of air taken into the cylinder 11 of the internal combustion engine 1 at a certain value, that is, when the temperature of the layer 1412 rises above the temperature T ₂ at which HC desorption occurs (step S5), as compared with other times. The fuel injection amount is controlled to be larger, and the spark ignition timing to the air-fuel mixture in the cylinder 11 is controlled to be further retarded (step S6).

As already described in the first embodiment, the ECU 0 repeatedly estimates the current floor temperature of the exhaust gas purification device 141 (or the temperature of the carrier 1413, the adsorption layer 1412 or the catalyst layer 1411) at predetermined intervals. ing. In step S5, the estimated temperature is compared with the HC desorption temperature T ₂ . Of course, if the ECU 0 can actually measure the current temperature of the exhaust gas purification device 141 via the temperature sensor, the measured temperature may be compared with the HC desorption temperature T ₂ .

In step S6, for example, by setting the target engine speed or idle speed higher than the normal value and expanding the opening degree of the throttle valve 132 more than normal, the intake air amount and the fuel injection amount are set higher than normal. Increase the amount. The fuel injection amount at this time is also set so that the air-fuel ratio of the air-fuel mixture filled in the cylinder 1 becomes the stoichiometric air-fuel ratio or a target air-fuel ratio in the vicinity thereof. When the ignition timing is delayed from the normal angle, the temperature of the exhaust gas discharged from the cylinder 11 and flowing into the exhaust gas purification device 141 becomes high.

By controlling step S6 in which the ignition timing is retarded while increasing the intake air amount, the exhaust gas flowing through the exhaust gas purification device 141 becomes hot and has a larger flow rate. Therefore, as shown in FIG. 8, after the temperature of the adsorption layer 1412 (drawn by a thick broken line in the figure) reaches the HC desorption temperature T ₂ , the temperature of the catalyst layer 1411 (drawn by a thin solid line in the figure) is drawn. ) Rise faster. That is, the period B from when the temperature of the HC adsorption layer 1412 reaches T ₂ to when the temperature of the three-way catalyst layer 1411 reaches T ₁ is shortened. As a result, it becomes possible to reduce the amount of HC released to the outside immediately after the start of the internal combustion engine 1 as compared with the conventional case.

When the temperature of the three-way catalyst layer 1411 of the exhaust gas purification device 141 rises above the activation temperature T ₁ (step S7), the ECU 0 ends the control of step S6 and is sucked into the cylinder 11 of the internal combustion engine 1. The amount of air and the amount of fuel injected are reduced to the normal amount, and the spark ignition timing of the air-fuel mixture in the cylinder 11 is advanced to the normal timing (step S4). In step S7, the current estimated temperature or the measured temperature of the exhaust gas purification device 141 (or the carrier 1413, the adsorption layer 1412 or the catalyst layer 1411) is compared with the activation temperature T ₁ .

In the present embodiment, the internal combustion engine 1 is provided with a purification device 141 having an adsorption layer 1412 for adsorbing HC contained in the exhaust gas discharged from the cylinder 11 and a catalyst layer 1411 for oxidizing HC. At the time when the temperature of the adsorption layer 1412 after the start of the internal combustion engine 1 seems to reach a certain value T ₂ or higher, the amount of air sucked into the cylinder 11 is larger and the ignition timing is higher than at other times. The internal combustion engine 1 is configured so that the angle is controlled to be more retarded and the temperature rise of the catalyst layer 1411 is promoted. According to the present embodiment, immediately after the start of the internal combustion engine 1, the amount of HC desorbed from the adsorption layer 1412 that is not purified by the catalyst layer 1411 and is released to the outside can be further reduced.

The present invention is not limited to the embodiment described in detail above. For example, it is naturally possible to combine the above-mentioned first embodiment and the second embodiment. In that case, first, in the period immediately after the start of the internal combustion engine 1, the amount of air sucked into the cylinder 11 is smaller and the ignition timing is further retarded as compared with the other periods. Then, when the temperature of the adsorption layer 1412 is considered to be a certain value T ₂ or higher, the amount of air sucked into the cylinder 11 is larger and the ignition timing is further retarded as compared with other times. ..

Further, the internal combustion engine 1 according to the present invention can be mounted as a power source on a conventional vehicle that travels by inputting engine torque exclusively output by the internal combustion engine 1 to the drive wheels, which is not a hybrid vehicle.

In addition, the specific configuration of each part, the processing procedure, and the like can be variously modified without departing from the spirit of the present invention.

The present invention can be used for controlling an internal combustion engine mounted on a vehicle or the like.

0 ... Control unit (ECU)
1 ... Internal combustion engine 11 ... Cylinder 111 ... Injector 112 ... Ignition plug 13 ... Intake passage 132 ... Electronic throttle valve 14 ... Exhaust passage 141 ... Exhaust purification device 1411 ... Catalyst layer 1412 ... Suction layer 2 ... Motoring (cranking) motor (Motor generator for power generation)
i ... Ignition signal j ... Fuel injection signal k ... Throttle valve opening operation signal

Claims (2)

An internal combustion engine in which a purification device having an adsorption layer for adsorbing HC contained in exhaust gas discharged from a cylinder and a catalyst layer for oxidizing HC is provided in an exhaust passage.
Immediately after the start of the internal combustion engine, the amount of air sucked into the cylinder is controlled to be smaller and the ignition timing is more retarded than at other times, and the heat capacity of the adsorption layer and the catalyst layer is controlled. An internal combustion engine in which the temperature rise of the adsorption layer is delayed from the temperature rise of the catalyst layer due to the difference between the two. An internal combustion engine in which a purification device having an adsorption layer for adsorbing HC contained in exhaust gas discharged from a cylinder and a catalyst layer for oxidizing HC is provided in an exhaust passage.
When the temperature of the adsorption layer is considered to be above a certain value after the start of the internal combustion engine, the amount of air sucked into the cylinder is larger and the ignition timing is delayed more than at other times. An internal combustion engine that is controlled and promotes a temperature rise of the catalyst layer.

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