JP2019035337A - Driving device and vehicle - Google Patents

Abstract

To provide a driving device capable of reducing the pressure loss caused by ash deposited in a PM filter.SOLUTION: A driving device includes an internal combustion engine 10 generating motive power, a continuous regeneration type PM filter 42 arranged in an exhaust passage 30 of the internal combustion engine 10, and a control device 60 for controlling a fuel injection device 11 of the internal combustion engine 10. The control device 60 controls the fuel injection device 11 and raises a temperature of exhaust gas discharged from the internal combustion engine 10 so that ash deposited in the PM filter 42 is scaled off from a collection wall 42a of the PM filter 42 at any timing during continuous regeneration of the PM filter 42.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a drive device and a vehicle.

  In general, an exhaust passage of an internal combustion engine is provided with an exhaust purification device such as a PM filter that collects particulate matter (PM) contained in exhaust gas.

Since this type of PM filter has an upper limit on the amount of PM that can be collected, when PM accumulates in the PM filter, filter regeneration is performed to burn and remove the PM in the PM filter. As a regeneration method of this PM filter, a continuous regeneration method in which PM is oxidized and removed at a normal exhaust gas temperature (for example, about 300 ° C.) by mainly generating NO ₂ using an oxidation catalyst, A forced regeneration method is used in which the exhaust gas is heated to about 600 ° C. to burn and remove PM (see, for example, Patent Document 1).

JP 2005-069238 A

By the way, in this kind of PM filter, as the operation frequency and operation time of the internal combustion engine (for example, the travel distance and travel time of the vehicle) become longer, not only the accumulation of soot PM but also the engine contained in the exhaust gas It is known that ash (ash-like substance) due to oil components (for example, CaSO ₄ ) is deposited.

  Such ash requires high heat of 800 ° C. or higher to be removed by combustion, and therefore is not removed even when PM is forcibly regenerated, and continues to accumulate in the PM filter. The ash that accumulates in the PM filter causes a pressure loss in the same way as PM. Therefore, there is a problem that the pressure loss in the PM filter increases as the accumulation amount increases, leading to deterioration in fuel consumption.

  The present disclosure has been made in view of the above-described problems, and an object thereof is to provide a drive device and a vehicle that can reduce pressure loss due to ash accumulated in a PM filter.

An internal combustion engine that generates power;
A continuously regenerating PM filter disposed in an exhaust passage of the internal combustion engine;
A control device for controlling the fuel injection device of the internal combustion engine;
With
The control device controls the fuel injection device so that the ash accumulated in the PM filter is separated from the collection wall of the PM filter at any timing when the PM filter is continuously regenerated. And increasing the temperature of the exhaust gas discharged from the internal combustion engine,
It is a drive device.

In other aspects,
It is a vehicle provided with said drive device.

  According to the control device for an internal combustion engine according to the present disclosure, it is possible to reduce the pressure loss due to the ash accumulated in the PM filter.

The figure which shows an example of the structure of the vehicle which concerns on embodiment The figure which shows an example of a structure of the fuel-injection apparatus of the engine main body which concerns on embodiment The figure which shows an example of a structure of PM filter which concerns on embodiment The figure which shows an example of a structure of PM filter which concerns on embodiment The figure which shows an example of the control map regarding the fuel injection quantity which the fuel supply control part which concerns on embodiment refers to The figure which shows an example of the control map regarding the injection timing which the fuel supply control part which concerns on embodiment refers to The flowchart which shows an example of operation | movement of ECU which concerns on embodiment The figure which shows a mode that an ash changes form by control of ECU which concerns on embodiment.

[Vehicle configuration]
Hereinafter, the configuration of the driving apparatus according to the embodiment will be described with reference to FIGS.

  In the present embodiment, a mode applied to a vehicle equipped with a self-ignition internal combustion engine (hereinafter also referred to as “diesel engine”) will be described as an example of a drive device. However, the drive device according to the present invention can be applied not only to a vehicle equipped with a diesel engine but also to a vehicle equipped with a gasoline engine.

  FIG. 1 is a diagram illustrating an example of a configuration of a vehicle 1 according to the present embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the fuel injection device 11 of the engine body 10 according to the present embodiment. 3 and 4 are diagrams illustrating an example of the configuration of the PM filter 42 according to the present embodiment.

  The vehicle 1 according to the present embodiment includes an engine body 10, an intake passage 20, an exhaust passage 30, an air cleaner 21, a turbo charger 22, an intake throttle valve 23, an EGR device 31, an exhaust purification device 40, various sensors 51 to 53, and an ECU. (Electronic Control Unit) 60 etc. are comprised.

  The engine body 10 includes a combustion chamber, a fuel injection device 11 (see FIG. 2), and the like. The engine body 10 generates power for the vehicle 1 by repeatedly performing an air intake stroke, an air compression stroke, a combustion gas expansion stroke, and a combustion gas exhaust stroke in the combustion chamber.

  The fuel injection device 11 is, for example, a common rail type fuel injection device, and injects fuel directly into the combustion chamber, common rail 11b that stores fuel to be supplied to the injector 11a in a high pressure state, and pressure-feeds the fuel to the common rail 11b. A pressure pump 11c and a fuel tank 11d for supplying fuel to the pressure pump 11c are configured.

  The fuel injection device 11 controls opening and closing of the electromagnetic valve of the injector 11a in accordance with a control signal Sa from the ECU 60, thereby injecting fuel into the combustion chamber.

  The engine body 10 according to the present embodiment is a four-cylinder engine, and branches from the intake passage 20 to four combustion chambers via the intake manifold, and from the four combustion chambers to the exhaust passage 30 via the exhaust manifold. It is configured to merge.

  The intake passage 20 is a flow path that draws fresh air (air) from the upstream intake port 20 a and supplies the fresh air to the engine body 10. In the intake passage 20, an air cleaner 21, a compressor of a turbocharger 22, an intake throttle valve 23, and the like are provided in order from the upstream intake port 20 a to the combustion chamber.

  The exhaust passage 30 is a flow path for discharging the exhaust gas after combustion discharged from the engine body 10 to the outside of the vehicle 1. The exhaust passage 30 is provided with an EGR device 31, a turbine of the turbocharger 22, an exhaust purification device 40, and the like in order from the engine body 10 toward the downstream side.

  The EGR device 31 connects the exhaust passage 30 and the intake passage 20 and recirculates a part of the exhaust gas discharged from the combustion chamber of the engine body 10 to the exhaust passage 30 to the intake passage 20, and EGR It includes an EGR valve 31b that adjusts the amount of exhaust gas flowing through the passage 31a and adjusts the EGR amount. The EGR valve 31b operates based on a control signal Sb from the ECU 60.

  The exhaust purification device 40 includes an oxidation catalyst 41 and a PM filter 42.

  The oxidation catalyst 41 oxidizes and removes unburned fuel hydrocarbons and carbon monoxide contained in the exhaust gas. The oxidation catalyst 41 may be any known oxidation catalyst such as platinum or cerium oxide. For example, a porous ceramic such as cordierite or silicon carbide is used, and the catalyst component is supported thereon. .

Further, the oxidation catalyst 41 is disposed adjacent to the upstream side of the PM filter 42 in the exhaust passage 30. When the PM filter 42 is continuously regenerated, the oxidation catalyst 41 converts NOx in the exhaust gas into NO _{2 and the} like, and exhausts the exhaust gas to a desired level (for example, about 300 ° C.) for oxidizing and removing the PM. It also functions to raise the gas temperature.

  The PM filter 42 captures PM contained in the exhaust gas (see FIGS. 3 and 4). As the PM filter 42, a porous ceramic of cordierite or silicon carbide is typically used as a material, and the PM filter 42 is configured so that exhaust gas passes through a collection wall 42a formed of the porous ceramic. A honeycomb structure in which inlets and outlets are alternately plugged is also referred to as a wall flow type.

  The PM filter 42 according to the present embodiment uses a continuous regeneration type PM filter having an oxidation catalyst 41 as a separate body upstream of itself, but has an oxidation catalyst as its own carrier. May be used.

As described above, ash due to engine oil components (for example, CaSO ₄ ) is collected on the porous collection wall 42 a of the PM filter 42 as described above. The ash is usually deposited in a layered manner on the surface of the porous collection wall 42a of the PM filter 42 (also referred to as wall ash, indicated by A1 in FIG. 4), and part of the ash is on the downstream side. It is swept away by the plugged portion and accumulated in a lump (also referred to as plug ash, indicated by A2 in FIG. 4).

  The wall ash A1 covers the surface of the porous collection wall 42a in a layered manner, so that the degree of blocking the passage of exhaust gas is larger and the pressure loss is larger than the plug ash A2. In the present embodiment, from the viewpoint of reducing the pressure loss, the form of the ash accumulated in the PM filter 42 is changed from the wall ash A1 to the plug ash A2 by controlling the engine body 10 (details will be described later).

  Various sensors 51 to 53 are provided for detecting the state of each part of the vehicle 1 and the like. Specifically, each part of the vehicle 1 is provided with a PM sensor 51, an accelerator opening sensor 52, an engine rotation sensor 53, and the like. And these various sensors 51-53 sequentially transmit to ECU60 as the detection signal the information obtained by detection (dotted line in FIG. 1).

  Here, the PM sensor 51 is disposed in the exhaust passage 30 and detects the amount of PM contained in the exhaust gas discharged from the engine body 10. The engine rotation sensor 53 is a sensor that detects the number of rotations of the crankshaft of the engine body 10. The accelerator opening sensor 52 is a sensor that detects an operation amount of an accelerator operation performed by the driver. These various sensors 51 to 53 can be realized by known sensors.

[Configuration of ECU]
Next, an example of the configuration of the ECU 60 according to the present embodiment will be described with reference to FIGS. 5 and 6.

  The ECU 60 (corresponding to the “control device” of the present invention) is an electronic control unit that controls the fuel injection device 11 and the like of the engine body 10, and includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), A RAM (Random Access Memory), an input port, an output port, and the like are included. ECU60 controls these by communicating with each part of the vehicle 1, and receives data from these.

  The ECU 60 includes a filter regeneration control unit 60a and a fuel supply control unit 60b.

  The filter regeneration control unit 60a controls the engine body 10 and the like so as to perform regeneration of the PM filter 42.

  For example, the filter regeneration control unit 60 a determines the regeneration time of the PM filter 42 based on the detection signal from the PM sensor 51. When the filter regeneration control unit 60a determines that it is the regeneration time of the PM filter 42, for example, by controlling the EGR valve 31b of the EGR device 31, the EGR rate is reduced and the exhaust gas discharged from the engine body 10 is exhausted. The continuous regeneration is executed by increasing the amount of NOx contained in the. In addition, when performing the continuous regeneration, the filter regeneration control unit 60a, instead of this, or together with this, the temperature of the exhaust gas discharged from the engine body 10 is 200 ° C. or higher (for example, about 300 ° C.). Thus, the fuel supply control unit 60b may be commanded.

  In addition, the filter regeneration control unit 60a according to the present embodiment discharges from the engine body 10 at any timing when the PM filter 42 is continuously regenerated in order to change the form of the ash accumulated in the PM filter 42. In order to increase the temperature of the exhaust gas to be increased, the fuel supply control unit 60b is instructed to perform at least one of multi-injection or an increase in the fuel injection amount according to the accelerator opening.

  In the following description, an operation mode in which the engine body 10 is operated in a state where the temperature of the exhaust gas is increased by executing at least one of multi-injection or increasing the fuel injection amount according to the accelerator opening is referred to as “exhaust gas temperature increase mode”. The operation mode in which the engine body 10 is operated in a state where priority is given to fuel efficiency is referred to as “normal operation mode”, and the operation mode of the engine body 10 during continuous regeneration is referred to as “continuous regeneration operation mode”.

  For example, the fuel supply control unit 60b determines the operation state (for example, injection timing and injection amount) of the fuel injection device 11 based on the detection values of various sensors (the engine rotation sensor 53 or the accelerator opening sensor 52) and the control map. The fuel injection device 11 is controlled so as to be determined and to be in the operation state.

  Further, the fuel supply control unit 60b according to the present embodiment, for example, increases the fuel injection amount in accordance with the multi-injection or the accelerator opening when the start command of the exhaust gas temperature raising mode is issued from the filter regeneration control unit 60a. At least one of the executions is started, and the temperature of the exhaust gas is increased. At this time, the fuel supply control unit 60b controls the fuel so that the temperature of the exhaust gas discharged from the engine body 10 is further increased (for example, about 500 ° C.) from the temperature during continuous regeneration (for example, about 200 ° C.). The injection device 11 is controlled. Then, the fuel supply control unit 60b returns to the continuous regeneration operation mode and restarts the operation in response to a command to end the exhaust gas temperature raising mode from the filter regeneration control unit 60a.

FIG. 5 is a diagram illustrating an example of a control map related to the fuel injection amount referred to by the fuel supply control unit 60b. The horizontal axis of FIG. 5 is the engine speed [rpm], the vertical axis is the fuel injection amount [m ³ / s] of the fuel injection device 11, and FIG. 5 shows a control map when the accelerator opening is 100%. A control map when the accelerator opening is 30% and a control map when the accelerator opening is 0% are shown.

  FIG. 5 shows a control map for the normal operation mode and a control map for the exhaust gas temperature raising mode. As shown in the control map for the exhaust gas temperature increase mode, the fuel supply control unit 60b has a fuel injection amount corresponding to the accelerator opening that is greater in the exhaust gas temperature increase mode than in the normal operation mode. This increases the temperature of the exhaust gas.

  FIG. 6 is a diagram illustrating an example of a control map related to the injection timing referred to by the fuel supply control unit 60b. The horizontal axis in FIG. 6 is the crank angle (TDC in the figure represents compression top dead center and BTDC represents bottom dead center), and the vertical axis represents the ratio (fuel injection rate) to the maximum value of the fuel injection amount of the fuel injection device 11. Show.

  FIG. 6 shows a control map for the normal operation mode and a control map for the exhaust gas temperature raising mode. As shown in the control map for the exhaust gas temperature increase mode, the fuel supply control unit 60b performs post injection and after injection in addition to the main injection in the exhaust gas temperature increase mode.

  In the after injection, the exhaust gas temperature can be increased by completely burning the unburned fuel of the main injection. Further, in the post injection, a part of the fuel is discharged without being burned, so that it can be burned by the oxidation catalyst 41 or the like, and the exhaust gas temperature can be raised.

  In the present embodiment, the control map for the normal operation mode shown in FIGS. 5 and 6 is referred to in the continuous regeneration operation mode.

  The filter regeneration control unit 60a and the fuel supply control unit 60b are realized, for example, when the CPU refers to a control program and various data stored in a ROM, a RAM, or the like. However, the function is not limited to processing by software, and can of course be realized by a dedicated hardware circuit.

[Ashes control]
Next, the operation of the ECU 60 for performing ash form control will be described with reference to FIGS.

  FIG. 7 is a flowchart showing an example of the operation of the ECU 60. The flowchart shown in FIG. 7 is executed, for example, by the filter regeneration control unit 60a of the ECU 60 at predetermined intervals (for example, every second) according to the computer program.

  In step S1, the filter regeneration control unit 60a first estimates the amount of ash deposited in the PM filter 42, and estimates whether or not the ash has accumulated a predetermined amount or more. Then, when the filter regeneration control unit 60a determines that the ash is accumulated in a predetermined amount or more (step S1: YES), the filter regeneration control unit 60a performs the subsequent process of step S2. On the other hand, when it is determined that the ash has not accumulated more than a predetermined amount (step S1: NO), the filter regeneration control unit 60a ends the series of processes without executing any particular process.

  In step S1, the filter regeneration control unit 60a, for example, the elapsed time since execution of the previous exhaust gas temperature increase mode, the travel distance since execution of the previous exhaust gas temperature increase mode, or various sensors ( The amount of ash deposited in the PM filter 42 is estimated based on the detected value (not shown).

  In step S2, the filter regeneration control unit 60a determines whether continuous regeneration of the PM filter 42 is being performed. Then, when the PM filter 42 is being continuously regenerated (step S2: YES), the filter regeneration control unit 60a executes the subsequent process of step S3. On the other hand, when the PM filter 42 is not being continuously regenerated (step S2: NO), the filter regeneration control unit 60a ends the series of processes without executing any particular process.

  In step S3, the filter regeneration control unit 60a determines whether or not the execution time of the continuous regeneration of the PM filter 42 has passed a predetermined time (for example, 1 minute). Then, when the predetermined time has not elapsed (step S3: NO), the filter regeneration control unit 60a waits until the predetermined time elapses, and according to the elapse of the predetermined time (step S3: YES). Then, the process of step S4 is executed.

  Note that the continuous regeneration execution time determined by the filter regeneration control unit 60a in step S3 is set based on the time during which PM around the ash can be removed (described later with reference to FIG. 8).

  In step S4, the filter regeneration control unit 60a instructs the fuel supply control unit 60b to start the exhaust gas temperature raising mode. Accordingly, as shown in FIGS. 5 and 6, the fuel supply control unit 60b changes the temperature of the exhaust gas during the continuous regeneration by executing the multi-injection and increasing the fuel injection amount according to the accelerator opening. The fuel injection device 11 is controlled so that the temperature becomes higher (for example, about 500 ° C.) than the temperature (for example, about 200 ° C.).

  In step S5, the filter regeneration control unit 60a causes the fuel supply control unit 60b to continue the control state until a predetermined time elapses in the exhaust gas temperature raising mode. Then, the filter regeneration control unit 60a waits for a predetermined time to elapse (step S5: NO), and executes the process of step S6 when the predetermined time elapses (step S5: YES).

  The execution time of the exhaust gas temperature raising mode set in step S5 is set on the basis of the time during which the ash accumulated in the PM filter 42 can be changed into a plug ash state (see FIG. 8). Later).

  In step S6, the filter regeneration control unit 60a instructs the fuel supply control unit 60b to end the exhaust gas temperature raising mode, and returns to the operation state in the continuous regeneration operation mode. A series of processes for changing the form of the ash deposited in the PM filter 42 is completed by performing the processes as described above.

  FIG. 8 shows in time series how the ash changes in form under the control of the filter regeneration control unit 60a according to the present embodiment.

  In the PM filter 42, first, ash is deposited on the collecting wall 42a together with PM. At this time, PM and ash are integrally attached to the collection wall 42a (FIG. 8A). At this time, the ash is hardly peeled off from the collection wall 42a due to the influence of the PM adhering to the periphery of the ash, and is deposited in a wall ash state.

  When the PM filter 42 is continuously regenerated, PM is removed by oxidation or combustion, so that only ash is deposited on the collection wall 42a (FIG. 8B). As a result, the ash deposited in the wall ash state is easily peeled off from the collection wall 42a.

  The ECU 60 according to the present embodiment executes the exhaust gas temperature raising mode during the continuous regeneration, and raises the temperature of the exhaust gas discharged from the engine body 10 (for example, about 500 ° C.). Since the exhaust gas having a high temperature has a high viscosity and volume flow rate, a large shear stress acts on the ash deposited in the wall ash state along the direction of peeling from the collection wall 42a. As a result, the ash is peeled off from the collection wall 42a and is aggregated in a lump shape with each other (FIG. 8C).

  As described above, the ash aggregated in a lump is easily subjected to a force from the exhaust gas, and thus is pushed away to the plugged portion on the downstream side of the PM filter 42 (FIG. 8D). In this way, most of the ash deposited in the wall ash state on the collection wall 42a is due to the shape change to the plug ash.

  As described above, the ECU 60 (control device for an internal combustion engine) according to the present embodiment has the fuel injection amount corresponding to the multi-injection or the accelerator opening at any timing when the PM filter 42 is continuously regenerated. By executing the increase, the fuel injection device 11 is controlled so that the exhaust gas discharged from the engine body 10 rises to a predetermined temperature (for example, 500 ° C.) or higher.

  According to the ECU 60 according to the present embodiment, the ash deposited in the wall ash state in the PM filter 42 can be changed into the plug ash state. As a result, pressure loss due to ash can be reduced, and fuel consumption can be improved.

  Further, according to the ECU 60 according to the present embodiment, the exhaust gas temperature raising mode is performed only for a temporary time during continuous regeneration, for example, 5 minutes (the “first time” of the present invention), and after the time has elapsed. Is again set to the continuous regeneration operation mode. Thereby, the deterioration of the fuel consumption by continuing the exhaust gas temperature rising mode unnecessarily can be suppressed.

  Further, according to the ECU 60 according to the present embodiment, the exhaust gas temperature raising mode is executed such that the temperature of the exhaust gas discharged from the engine body 10 exceeds 500 ° C. Thereby, the form change from wall ash to plug ash can be performed effectively.

  The ECU 60 according to the present embodiment is applied to a diesel engine. Since the diesel engine has a lower temperature of the exhaust gas than the gasoline engine, the ash accumulated in the PM filter 42 is easily maintained in the wall ash state. Therefore, the ECU 60 according to this embodiment is more suitable. Can be used.

(Other embodiments)
The present invention is not limited to the above embodiment, and various modifications can be considered.

  In the said embodiment, the control map of FIG.5 and FIG.6 was shown as an example of the exhaust gas temperature rising mode of the fuel supply control part 60b. However, the control for the fuel supply control unit 60b to raise the temperature of the exhaust gas can be variously changed. For example, the fuel supply control unit 60b may be configured to control the fuel injection device 11 so that either one of the multi-injection or the increase in the fuel injection amount according to the accelerator opening is executed. Further, the fuel supply control unit 60b may be configured to execute either post injection or after injection in FIG. In the case of a gasoline engine, the fuel injection amount according to the accelerator opening may be indirectly increased by increasing the valve opening of the throttle valve according to the accelerator opening.

  In the above embodiment, as an example of the ECU 60, the aspect in which the filter regeneration control unit 60 a controls the continuous regeneration of the PM filter 42 has been shown. However, since the continuous regeneration of the PM filter 42 is automatically executed even in the normal operation mode if the operation conditions are set, the ECU 60 is particularly suitable for the engine main body 10 in the continuous regeneration operation mode and the normal operation mode. It is good also as an aspect which does not change control of.

  In the above embodiment, as an example of the configuration of the ECU 60, the functions of the filter regeneration control unit 60a and the fuel supply control unit 60b are described as being realized by one computer, but may be realized by a plurality of computers. Of course.

  Moreover, in the said embodiment, the aspect applied to the vehicle 1 was shown as an example of the drive device provided with an internal combustion engine. However, it is needless to say that the drive device according to the present invention can be applied not only to a vehicle but also to other devices that require power, such as a ship and an aircraft.

  As mentioned above, although the specific example of this invention was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  According to the drive device according to the present disclosure, it is possible to reduce pressure loss due to ash accumulated in the PM filter.

DESCRIPTION OF SYMBOLS 1 Vehicle 10 Engine main body 11 Fuel injection device 20 Intake passage 21 Air cleaner 22 Turbocharger 23 Intake throttle valve 30 Exhaust passage 31 EGR device 40 Exhaust purification device 41 Oxidation catalyst 42 PM filter 42a Collection wall 51 PM sensor 52 Accelerator opening sensor 53 Engine rotation sensor 60 ECU
60a Filter regeneration control unit 60b Fuel supply control unit

Claims (8)

An internal combustion engine that generates power;
A continuously regenerating PM filter disposed in an exhaust passage of the internal combustion engine;
A control device for controlling the fuel injection device of the internal combustion engine;
With
The control device controls the fuel injection device so that the ash accumulated in the PM filter is separated from the collection wall of the PM filter at any timing when the PM filter is continuously regenerated. And increasing the temperature of the exhaust gas discharged from the internal combustion engine,
Drive device. The control device increases the temperature of the exhaust gas by causing the fuel injection device to execute multi-injection.
The drive device according to claim 1. The control device increases the temperature of the exhaust gas by increasing a fuel injection amount corresponding to an accelerator opening with respect to the fuel injection device.
The drive device according to claim 1 or 2. The control device increases the temperature of the exhaust gas so that the temperature of the exhaust gas is 500 ° C. or higher;
The drive apparatus as described in any one of Claims 1 thru | or 3. The control device increases the temperature of the exhaust gas only during a part of the time during which the PM filter is continuously regenerated.
The drive apparatus as described in any one of Claims 1 thru | or 4. The internal combustion engine is a self-ignition internal combustion engine.
The drive apparatus as described in any one of Claims 1 thru | or 5. The control device reduces an EGR rate of an EGR device attached to the internal combustion engine to a predetermined value or less when executing the continuous regeneration of the PM filter.
The drive apparatus as described in any one of Claims 1 thru | or 6.   A vehicle comprising the driving device according to any one of claims 1 to 7.

Images