JP2021169783A - Engine device - Google Patents

Abstract

To inhibit fuel injection control from becoming unstable immediately after a state where purging by using a second purge passage is dominant is switched to a state where purging by using a first purge passage is dominant.SOLUTION: An evaporated fuel treatment device supplies evaporated fuel gas to an intake pipe via a first purge passage connected to a downstream side of a throttle valve in the intake pipe and a second purge passage connected to a suction port of an ejector in which an exhaust port is connected to an upstream side of a compressor of a supercharger in the intake pipe. During dominant purge determination made to determine that purging by using the first purge passage is dominant when intake pressure on the downstream side of the throttle valve in the intake pipe is smaller than a threshold value and determine that purging by using the second purge passage is dominant when the intake pressure is equal to or greater than the threshold value, when the intake pressure reaches a value smaller than the threshold value from a value equal to or greater than the threshold value, a determination that the purging by using the second purge passage is dominant until a predetermined time has elapsed is made. By using a determination result, a purge control valve is controlled.SELECTED DRAWING: Figure 8

Description

The present invention relates to an engine device.

Conventionally, as this type of engine device, a first purge passage for purging downstream from the throttle valve and a second purge passage for purging upstream of the compressor of the supercharger by an ejector that generates negative pressure in the supercharger are used. (See, for example, Patent Document 1). In this engine device, the pressure of the intake pipe on the downstream side of the throttle valve is compared with the pressure generated by the ejector to detect whether the purging is performed by the first purge passage or the second purge passage. Then, when the purge passage is switched between the first purge passage and the second purge passage, the control characteristic data used for controlling the purge control valve is the first control characteristic data suitable for the first purge passage and the second. It is switched to the second control characteristic data suitable for the purge passage.

Japanese Unexamined Patent Publication No. 2019-052561

In the engine device described above, the fuel injection control may become unstable when the detection that the purge is performed by the second purge passage leads to the detection that the purge is performed by the first purge passage. be. When purging is carried out by the second purge passage, the fuel injection control associated with purging becomes unstable due to the long path until the purging reaches the downstream side of the throttle valve and fluctuations in the supercharging pressure due to the supercharger. Cheap. Therefore, the second control characteristic data suitable for the second purge passage used for controlling the purge control valve suppresses the purge as compared with the first control characteristic parameter suitable for the first purge passage. Further, when the detection that the purge is performed by the second purge passage leads to the detection that the purge is performed by the first purge passage, the purge remaining in the second purge passage and the first purge The purge newly supplied to the passage may be supplied to the downstream side of the throttle valve at the same time. At this time, if the first control characteristic parameter suitable for the first purge passage is used, the purge having a high purge rate from the first purge passage and the purge from the second purge passage are supplied, so that the fuel injection control is not possible. It will be stable.

The engine device of the present invention suppresses instability of fuel injection control immediately after switching from a state in which purging by the second purge passage is dominant to a state in which purging by the first purge passage is dominant. Is the main purpose.

The engine device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The engine device of the present invention
An engine that receives fuel from the fuel tank and has a throttle valve located in the intake pipe.
A supercharger having a compressor arranged on the upstream side of the throttle valve of the intake pipe, and
Evaporated fuel gas containing evaporated fuel generated in the fuel tank is branched into a first purge passage and a second purge passage connected to the downstream side of the throttle valve of the intake pipe and supplied to the intake pipe. An intake port is connected to a supply passage and a recirculation passage from between the compressor and the throttle valve of the intake pipe, and an exhaust port is connected to the upstream side of the intake pipe with respect to the compressor, and the second purge passage. An evaporative fuel treatment device having an ejector connected to a suction port and a purge control valve provided in the supply passage.
When the evaporated fuel gas is supplied to the intake pipe, the drive duty is set based on the fully open purge rate when the drive duty of the purge control valve is set to 100% and the required purge rate, and the purge control is performed. A control device that controls the valve and
It is an engine device equipped with
When the intake pressure on the downstream side of the throttle valve of the intake pipe is less than the threshold value, the control device determines that purging by the first purge passage is dominant and when the intake pressure is equal to or higher than the threshold value. In the dominant purge determination for determining that the purge by the second purge passage is dominant, when the intake pressure reaches from the threshold value or more to less than the threshold value, the second purge passage is used until a predetermined time elapses. It is determined that the purge is dominant, and the purge control valve is controlled using the determination result.
It is characterized by that.

In the engine device of the present invention, when the intake pressure on the downstream side of the throttle valve of the intake pipe is less than the threshold value, it is determined that purging by the first purge passage is dominant, and when the intake pressure is equal to or more than the threshold value, the first 2 Make a dominant purge judgment to determine that the purge by the purge passage is dominant. In this dominant purge determination, when the intake pressure reaches from the threshold value or more to less than the threshold value, it is determined that the purge by the second purge passage is dominant until a predetermined time elapses. That is, when the state in which the purge by the second purge passage is dominant changes to the state in which the purge by the first purge passage is dominant, it is determined that the purge by the second purge passage is dominant until a predetermined time elapses. To do. Since this determination result is used for controlling the purge control valve, when the intake pressure reaches from the threshold value or more to less than the threshold value, the control parameter when the purge by the second purge passage is dominant until a predetermined time elapses is used. The purge control valve is controlled. As described above, the control parameter when the purge by the second purge passage is dominant suppresses the purge as compared with the control parameter when the purge by the first purge passage is dominant. Therefore, even if the purge from the first purge passage and the purge from the second purge passage are supplied in an overlapping manner immediately after the intake pressure reaches the threshold value or less than the threshold value, the purge amount from the first purge passage is large. It is possible to prevent the fuel injection control from becoming unstable as compared with the case where the purge amount is small and the purge amount is large.

In the engine device of the present invention, the control device has a lower limit energization time obtained by using the smaller of the pressure generated in the suction port of the ejector and the pressure on the downstream side of the throttle valve of the intake pipe. The opening time of the purge control valve may be set using the drive duty. In this way, the opening time of the purge control valve can be set more appropriately.

It is a block diagram which shows the outline of the structure of the engine device 10 as one Example of this invention. It is explanatory drawing which shows an example of the input / output signal of an electronic control unit 70. It is a flowchart which shows an example of the purge control routine executed by the electronic control unit 70. It is a flowchart which shows an example of the control purge determination routine executed by an electronic control unit 70. It is explanatory drawing which shows an example of the time change of a surge pressure Ps and a purge flag Fp. It is explanatory drawing which shows an example of the map for estimation of the relative pressure of an ejector. It is explanatory drawing which shows an example of the map for full-open purge flow rate estimation. It is a flowchart which shows an example of the purge execution process executed by the electronic control unit 70. It is explanatory drawing which shows an example of the relationship between the drive energization time and the purge flow rate. It is explanatory drawing which shows an example of the map for setting the lower limit energization time.

Next, a mode for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of an engine device 10 as an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of an input / output signal of the electronic control unit 70. The engine device 10 of the embodiment is mounted on a general automobile or various hybrid automobiles, and as shown in FIGS. 1 and 2, an engine 12, a supercharger 40, an evaporative fuel processing device 50, and electronic control are provided. It includes a unit 70.

The engine 12 is configured as an internal combustion engine that outputs power using fuel such as gasoline or light oil supplied from the fuel tank 11 via a feed pump or a fuel passage (not shown). The engine 12 sucks the air cleaned by the air cleaner 22 into the intake pipe 23 and passes it through the intercooler 25, the throttle valve 26, and the surge tank 27 in this order. Then, fuel is injected (port injection) from the port injection valve 28a attached to the downstream side of the surge tank 27 of the intake pipe 23, air and fuel are mixed, and the fuel is sucked into the combustion chamber 30 via the intake valve 29. Fuel is injected (in-cylinder injection) from the in-cylinder injection valve 28b attached to the combustion chamber 30 to the air or air-fuel mixture sucked into the combustion chamber 30 via the intake valve 29, and electricity is supplied by the ignition plug 31. Explode and burn with sparks. The engine 12 converts the reciprocating motion of the piston 32 pushed down by the energy generated by such explosive combustion into the rotational motion of the crankshaft 14. The exhaust gas discharged from the combustion chamber 30 to the exhaust pipe 35 via the exhaust valve 34 is a catalyst (three-way catalyst) that purifies harmful components of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). ) Is discharged to the outside air through the purification devices 37 and 38. The engine 12 can be driven only by port injection, by only in-cylinder injection, and by both port injection and in-cylinder injection.

The supercharger 40 is configured as a turbocharger, and includes a compressor 41, a turbine 42, a rotating shaft 43, a wastegate valve 44, and a blow-off valve 45. The compressor 41 is arranged on the upstream side of the intercooler 25 of the intake pipe 23. The turbine 42 is arranged on the upstream side of the purification device 37 of the exhaust pipe 35. The rotating shaft 43 connects the compressor 41 and the turbine 42. The wastegate valve 44 is provided in the bypass pipe 36 that connects the upstream side and the downstream side of the turbine 42 in the exhaust pipe 35, and is controlled by the electronic control unit 70. The blow-off valve 45 is provided in the bypass pipe 24 that connects the upstream side and the downstream side of the compressor 41 in the intake pipe 23, and is controlled by the electronic control unit 70.

In the supercharger 40, by adjusting the opening degree of the wastegate valve 44, the distribution ratio of the displacement flowing through the bypass pipe 36 and the displacement flowing through the turbine 42 is adjusted, and the rotational driving force of the turbine 42 is adjusted. Then, the amount of compressed air by the compressor 41 is adjusted, and the supercharging pressure (intake pressure) of the engine 12 is adjusted. Here, in detail, the distribution ratio is adjusted so that the smaller the opening degree of the wastegate valve 44, the smaller the displacement through the bypass pipe 36 and the larger the displacement through the turbine 42. When the wastegate valve 44 is fully opened, the engine 12 can operate in the same manner as a naturally aspirated type engine without a supercharger 40.

Further, in the supercharger 40, when the pressure on the downstream side of the intake pipe 23 on the downstream side of the compressor 41 is higher than the pressure on the upstream side to some extent, the blow-off valve 45 is opened to cause a surplus on the downstream side of the compressor 41. The pressure can be released. The blow-off valve 45 is configured as a check valve that opens when the pressure on the downstream side of the compressor 41 in the intake pipe 23 becomes higher than the pressure on the upstream side to some extent, instead of the valve controlled by the electronic control unit 70. It may be done.

The evaporative fuel processing device 50 is the reverse of the introduction passage 52, the on-off valve 53, the bypass passage 54, the relief valves 55a and 55b, the canister 56, the purge passage 60, the buffer portion 64, and the purge control valve 65. It is provided with check valves 66 and 67, a return passage 68, and an ejector 69.

The introduction passage 52 is connected to the fuel tank 11 and the canister 56. The on-off valve 53 is provided in the introduction passage 52, and is configured as a normally closed type solenoid valve. The on-off valve 53 is controlled by the electronic control unit 70.

The bypass passage 54 has branch portions 54a and 54b that bypass the fuel tank 11 side and the canister 56 side of the opening / closing valve 53 of the introduction passage 52 and branch into two to join. The relief valve 55a is provided at the branch portion 54a and is configured as a check valve, and opens when the pressure on the fuel tank 11 side becomes to some extent higher than the pressure on the canister 56 side. The relief valve 55b is provided at the branch portion 54b and is configured as a check valve, and opens when the pressure on the canister 56 side becomes to some extent higher than the pressure on the fuel tank 11 side.

The canister 56 is connected to the introduction passage 52 and is open to the atmosphere through the atmosphere opening passage 57. The inside of the canister 56 is filled with an adsorbent such as activated carbon capable of adsorbing the evaporated fuel from the fuel tank 11. An air filter 58 is provided in the air opening passage 57.

The purge passage 60 is connected to the vicinity of the canister 56 of the introduction passage 52, and branches into the branch passage 62 and the branch passage 63 at a branch point 60a in the middle. Hereinafter, the portion of the purge passage 60 on the introduction passage 52 side of the branch point 60a is referred to as a “supply passage 61”. The branch passage 62 is connected between the throttle valve 26 of the intake pipe 23 and the surge tank 27. The branch passage 63 is connected to the suction port of the ejector 69.

The buffer portion 64 is provided in the supply passage 61. The inside of the buffer portion 64 is filled with an adsorbent such as activated carbon capable of adsorbing the evaporated fuel from the fuel tank 11 and the canister 56. The purge control valve 65 is provided on the branch point 60a side of the buffer portion 64 of the supply passage 61. The purge control valve 65 is configured as a normally closed type solenoid valve. The purge control valve 65 is controlled by the electronic control unit 70.

The check valve 66 is provided near the branch point 60a of the branch passage 62. The check valve 66 allows the flow of the evaporated fuel gas (purge gas) containing the evaporated fuel in the direction from the supply passage 61 side of the purge passage 60 to the branch passage 62 (intake pipe 23) side, and the evaporated fuel gas in the opposite direction. Prohibit the flow of. The check valve 67 is provided near the branch point 60a of the branch passage 63. The check valve 67 allows the flow of the evaporated fuel gas in the direction from the supply passage 61 side of the purge passage 60 to the branch passage 63 (executor 69) side, and prohibits the flow of the evaporated fuel gas in the reverse direction.

The return passage 68 is connected between the compressor 41 of the intake pipe 23 and the intercooler 25, and the intake port of the ejector 69. The ejector 69 has an intake port, a suction port, and an exhaust port. The intake port of the ejector 69 is connected to the return passage 68, the suction port is connected to the branch passage 63, and the exhaust port is connected to the upstream side of the compressor 41 of the intake pipe 23. The tip of the intake port is tapered.

In this ejector 69, when the supercharger 40 is operating (when the pressure between the compressor 41 of the intake pipe 23 and the intercooler 25 becomes positive pressure), the pressure between the intake port and the exhaust port becomes positive. A difference occurs, and a recirculation intake air (intake air recirculated from the downstream side of the compressor 41 of the intake pipe 23 via the recirculation passage 68) flows from the intake port to the exhaust port. At this time, the reflux intake air is depressurized at the tip of the intake port, and a negative pressure is generated around the tip. Then, due to the negative pressure, the evaporated fuel gas is sucked from the branch passage 63 through the suction port, and the evaporated fuel gas is brought to the upstream side of the compressor 41 of the intake pipe 23 through the exhaust port together with the negative pressure recirculation intake. Be supplied.

In the evaporated fuel processing device 50 configured in this way, the pressure on the downstream side of the throttle valve 26 of the intake pipe 23 (surge pressure Ps described later) is negative, and the on-off valve 53 and the purge control valve 65 are in the open state. At this time, the check valve 66 is opened, and the evaporated fuel gas (purge gas) generated in the fuel tank 11 and the evaporated fuel gas desorbed from the canister 56 pass through the introduction passage 52, the supply passage 61, and the branch passage 62. It is supplied to the downstream side of the throttle valve 26 of the intake pipe 23 via the air. Hereinafter, this is referred to as "downstream purge". At this time, if the pressure between the compressor 41 of the intake pipe 23 and the intercooler 25 (supercharging pressure Pc described later) is negative pressure or zero, the ejector 69 does not operate and the check valve 66 closes. It becomes a state.

Further, when the pressure between the compressor 41 of the intake pipe 23 and the intercooler 25 is positive and the on-off valve 53 and the purge control valve 65 are in the open state, the check valve 67 is opened by the operation of the ejector 69. In the valve state, the vaporized fuel gas is supplied to the upstream side of the compressor 41 of the intake pipe 23 via the introduction passage 52, the supply passage 61, the branch passage 63, and the ejector 69. Hereinafter, this is referred to as "upstream purge". At this time, if the pressure difference between the pressure in the supply passage 61 and the pressure on the downstream side of the throttle valve 26 of the intake pipe 23 is equal to or greater than the opening pressure of the check valve 66, for example, the surge pressure Ps is a negative pressure. If there is), the check valve 66 is also opened, and downstream purging is also performed. That is, both downstream purging and upstream purging are performed (evaporated fuel gas is supplied to both the downstream side of the intake pipe 23 from the throttle valve 26 and the upstream side from the compressor 41). On the other hand, if this pressure difference is less than the valve opening pressure of the check valve 66, the check valve 66 is closed and downstream purging is not performed. That is, only upstream purging is performed.

The electronic control unit 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. Signals from various sensors are input to the electronic control unit 70 via input ports.

The signals input to the electronic control unit 70 include, for example, the pressure Pt from the pressure sensor 11a that detects the pressure in the fuel tank 11 and the crank position sensor 14a that detects the rotational position of the crank shaft 14 of the engine 12. Examples include the crank angle θcr, the cooling water temperature Tw from a water temperature sensor (not shown) that detects the temperature of the cooling water of the engine 12, and the throttle opening TH from the throttle position sensor 26a that detects the opening degree of the throttle valve 26. Cam position θca from a cam position sensor (not shown) that detects the rotational position of the intake camshaft that opens and closes the intake valve 29 and the exhaust cam shaft that opens and closes the exhaust valve 34 can also be mentioned. The intake air amount Qa from the air flow meter 23a attached to the upstream side of the compressor 41 of the intake pipe 23, the intake pressure Pin from the pressure sensor 23b attached to the upstream side of the compressor 41 of the intake pipe 23, and the intake pipe. The boost pressure Pc from the pressure sensor 23c mounted between the compressor 41 of the 23 and the intercooler 25 can also be mentioned. The surge pressure Ps from the pressure sensor 27a attached to the surge tank 27 and the surge temperature Ts from the temperature sensor 27b attached to the surge tank 27 can also be mentioned. The front air-fuel ratio AF1 from the front air-fuel ratio sensor 35a attached to the upstream side of the purification device 37 of the exhaust pipe 35, and the rear air-fuel ratio sensor attached between the purification device 37 of the exhaust pipe 35 and the purification device 38. The rear air-fuel ratio AF2 from 35b can also be mentioned. Examples include the opening degree Op of the purge control valve 65 from the purge control valve position sensor 65a and the sensor signal Pobd from the OBD sensor (pressure sensor) 63a attached to the second purge passage 63.

Various control signals are output from the electronic control unit 70 via the output port. Examples of the signal output from the electronic control unit 70 include a control signal to the throttle valve 26, a control signal to the port injection valve 28a and the in-cylinder injection valve 28b, and a control signal to the spark plug 31. .. A control signal to the wastegate valve 44, a control signal to the blow-off valve 45, and a control signal to the on-off valve 53 can also be mentioned. A control signal to the purge control valve 65 can also be mentioned.

The electronic control unit 70 calculates the rotation speed Ne of the engine 12 based on the crank angle θcr from the crank position sensor 14a. Further, the electronic control unit 70 is actually sucked in one cycle with respect to the engine load factor (the stroke volume per cycle of the engine 12) based on the intake air amount Qa from the air flow meter 23a and the rotation speed Ne of the engine 12. The ratio of the volume of air) KL is calculated.

In the engine device 10 of the embodiment configured in this way, the electronic control unit 70 controls the intake air amount that controls the opening degree of the throttle valve 26 based on the required load factor KL * of the engine 12, and the port injection valve 28a and the like. Fuel injection control that controls the fuel injection amount from the in-cylinder injection valve 28b, ignition control that controls the ignition timing of the ignition plug 31, supercharging control that controls the opening degree of the wastegate valve 44, and the opening degree of the purge control valve 65. Performs purge control and the like to control.

Next, the operation of the engine device 10 of the embodiment thus configured, particularly the purge control, will be described. FIG. 3 is a flowchart showing an example of a purge control routine executed by the electronic control unit 70, and FIG. 4 is for determining whether the dominant purge is a downstream purge or an upstream purge. It is a flowchart which shows an example of the control purge determination routine executed by an electronic control unit 70. These routines are repeatedly executed when purging control is performed. For ease of explanation, the dominant purge determination will be described using the dominant purge determination routine shown in FIG. 4, and then the purge control based on the determination will be described using the purge control routine of FIG. ..

When the control purge determination routine is executed, the electronic control unit 70 first inputs surge pressures Ps (step S200). Here, a value detected by the pressure sensor 27a is input as the surge pressure Ps. Subsequently, the surge pressure Ps and the threshold value Pref are compared (step S210). The threshold value Pref is a threshold value for determining whether the downstream purge is dominant or the upstream purge is dominant, and can be obtained by experiments or the like. Basically, when the surge pressure Ps is less than the threshold value Pref, the downstream purge is dominant, and when the surge pressure Ps is equal to or more than the threshold value Pref, the upstream purge is dominant.

When it is determined in step S210 that the surge pressure Ps is less than the threshold value Pref, it is examined whether or not the purge flag Fp has a value of 1 (step S220). The purge flag Fp is set in this routine, and the value 0 is set when the downstream purge is dominant, the value 1 is set when the upstream purge is dominant, and the value 0 is set as the initial value. Will be done. Therefore, the determination in steps S210 and S220 is to determine whether or not the surge pressure Ps has reached the threshold value Pref from the state in which the upstream purge is dominant (purge flag Fp is a value 1). Considering that the downstream purge is dominant (purge flag Fp has a value of 0), a negative determination is made in step S220, and this routine ends without changing the purge flag Fp.

When it is determined in step S210 that the surge pressure Ps is equal to or greater than the threshold value Pref, it is determined that the upstream purge is dominant, the purge flag Fp is set to a value 1 (step S250), and this routine is terminated.

When the surge pressure Ps becomes less than the threshold value Pref from the state where the upstream purge is dominant (purge flag Fp is a value 1), a positive judgment is made in both steps S210 and S220, and after the purge pressure Ps becomes less than the threshold value Pref. Waiting for the elapse of a predetermined time (step S230), the purge flag Fp is set to a value 0 (step S240), and this routine is terminated. Here, as the predetermined time, the difference between the time until the purge at the time of upstream purging reaches the surge tank 27 and the time until the purge at the time of downstream purging reaches the surge tank 27 can be used. When the upstream purge is dominant, the downstream purge is dominant because the route from the purge to the surge tank 27 is long and the fuel injection control associated with the purge tends to become unstable due to fluctuations in the boost pressure Pc. A control parameter is used in which purging is suppressed compared to when. Immediately after the surge pressure Ps reaches the threshold value Pref or higher and the surge pressure Ps falls below the threshold value Pref, the purge remaining in the second purge passage 63 and the purge newly supplied to the first purge passage 62 are the surge tank 27. May be supplied to. At this time, if the control parameter suitable for the downstream purge is used assuming that the dominant purge is the downstream purge, the fuel injection control becomes unstable. To avoid this, the dominant purge waits for a predetermined time to elapse when switching from the upstream purge to the downstream purge. FIG. 5 shows an example of the time change of the surge pressure Pc and the purge flag Fp by the dominant purge determination routine. The purge flag Fp is set to a value 1 at the time T1 when the surge pressure Ps is from less than the threshold value Pref to more than the threshold value Pref. After that, the purge flag Fp is set to a value 0 at the time T3 when a predetermined time elapses from the time T2 from the time when the surge pressure Ps is equal to or more than the threshold value to less than the threshold value Pref.

Next, purge control will be described using the purge control routine of FIG. When the purge control routine is executed, the electronic control unit 70 first determines the intake air amount Qa, the intake pressure Pin, the boost pressure Pc, the surge pressure Ps, the target purge rate Rptg, the required duty Drq, and the upper limit purge rate Rplim. Data such as is input (step S100). Here, a value detected by the air flow meter 23a is input as the intake air amount Qa. A value detected by the pressure sensor 23b is input to the intake pressure Pin. The value detected by the pressure sensor 23c is input to the boost pressure Pc. A value detected by the pressure sensor 27a is input as the surge pressure Ps. The target purge rate Rptg is set to gradually increase from the start purge rate Rp11 when the purge control is executed for the first time in each trip during the downstream purge, and when the purge control is executed after the second time (purge). When the control is interrupted and then resumed), the one set to gradually increase from the restart purge rate Rp12 is input. Further, the target purge rate Rptg is set so as to gradually increase from the start purge rate Rp21, which is smaller than the start purge rate Rp11 at the time of downstream purge, when the purge control is executed for the first time in each trip at the time of upstream purge. When the purge control is executed from the second time onward, the one set to be gradually increased from the restart purge rate Rp12 smaller than the restart purge rate Rp12 at the time of downstream purge is input. As the start purge rates Rp11 and Rp21, relatively small values are used in order to suppress the disturbance of the air-fuel ratio in the combustion chamber 29. Examples of when the purge control is interrupted include when the accelerator is off while the vehicle on which the engine device 10 is mounted is running and the fuel of the engine 12 is cut. As the restart purge rates Rp12 and Rp22, values equal to or less than the required purge rate Rprq immediately before interruption (see step S140 described later) are used. The required duty Drq is input as set in step S160 when this routine was executed last time. As for the upper limit purge rate Rplim, the upper limit purge rate Rp1 is set when the downstream purge is dominant, and the upper limit purge rate Rp2 smaller than the upper limit purge rate Rp1 of the downstream purge is set when the upstream purge is dominant. Entered.

When the data is input in this way, the ejector relative pressure Pej is estimated based on the value obtained by subtracting the intake pressure Pin from the boost pressure Pc (Pc-Pin) and the required duty Drq (step S110). Here, the ejector relative pressure Pej is for estimating the ejector relative pressure by obtaining the relationship between the value obtained by subtracting the intake pressure Pin from the boost pressure Pc (Pc-Pin), the required duty Drq, and the ejector relative pressure Pej in advance by experiments or the like. It can be obtained by storing it as a map and applying the value obtained by subtracting the intake pressure Pin from the boost pressure Pc (Pc-Pin) and the required duty Drq to this map. FIG. 6 shows an example of the map for estimating the relative pressure of the ejector. As shown in the figure, it is estimated that the ejector relative pressure Pej increases as the required duty Drq increases, and increases as the boost pressure Pc increases.

Subsequently, the fully open purge flow rate Qpmax is estimated based on the smaller of the surge pressure Ps and the ejector relative pressure Pej (step S120). Here, the fully open purge flow rate Qpmax is the purge flow rate (volumetric flow rate of the evaporated fuel gas supplied to the intake pipe 23) when the drive duty of the purge control valve 65 is 100%, and the map for estimating the fully open purge flow rate is provided. Obtained using. The fully open purge flow rate estimation map is predetermined by experiments and analysis as the relationship between the surge pressure Ps and the ejector relative pressure Pej and the fully open purge flow rate Qpmax, and is stored in a ROM (not shown). FIG. 7 is an explanatory diagram showing an example of a map for estimating the fully open purge flow rate. As shown in the figure, the fully open purge flow rate Qpmax is estimated to increase as the surge pressure Ps and the ejector relative pressure Pej become smaller (larger as a negative pressure).

Next, the combustion chamber, which is the amount of air in the combustion chamber 30, is based on the intake air amount Qa and the upstream purge amount (past Qvup) estimated in the process of step S180 described later when this routine was executed in the past. The air volume Qcc is estimated (step S130). Here, the upstream purge amount Qvup is the flow rate of the evaporated fuel gas on the introduction passage 52 side with respect to the purge control valve 65. For the combustion chamber air amount Qcc, for example, the intake air amount Qa and the past upstream purge amount (past Qvup) are applied to the relationship between the intake air amount Qa and the past upstream purge amount (past Qvup) and the combustion chamber air amount Qcc. Can be obtained. As the past upstream purge amount (past Qvup), it is preferable to use the previous upstream purge amount Qvup for a longer time as the engine speed Ne is smaller, but for the sake of simplicity, it is upstream by a certain time. The purge amount Qvup may be used.

When the fully open purge flow rate Qpmax and the combustion chamber air amount Qcc are obtained in this way, the fully open purge rate Rpmax is estimated based on these (step S140). The fully open purge rate Rpmax can be calculated by dividing the fully open purge flow rate Qpmax by the amount of air in the combustion chamber Qcc.

Next, the target purge rate Rptg is limited by the fully open purge rate Rpmax and the upper limit purge rate Rplim (upper limit guard), and the required purge rate Rprq is set (step S150). That is, the required purge rate Rprq is set as the smallest value among the target purge rate Rptg, the fully open purge rate Rpmax, and the upper limit purge rate Eplim. Then, the required purge rate Rprq is divided by the fully open purge rate Rpmax to set the required duty Drq of the purge control valve 65 (step S160), and the purge execution process for driving the purge control valve 65 using the set required duty Drq is performed. (Step S170). Then, the upstream purge amount Qvup is estimated based on the intake air amount Qa and the required purge rate Rprq (step S180), and this routine is terminated. For the upstream purge amount Qvup, for example, the relationship between the intake air amount Qa, the required purge rate Rprq, and the upstream purge amount Qvup is obtained in advance by an experiment or the like and stored as a map for setting the upstream purge amount, and the intake air amount is stored in this map. It can be estimated by applying and deriving Qa and the required purge rate Rprq.

FIG. 8 is a flowchart showing an example of the purge execution process executed in step S170 of the purge control routine of FIG. When the purge execution process is executed, the electronic control unit 70 first inputs data such as surge pressure Ps, ejector relative pressure Pej, and required duty Drq (step S300). A value detected by the pressure sensor 27a is input as the surge pressure Ps. The ejector relative pressure Pej is input as estimated in step S110 of the purge control routine of FIG. The required duty Drq is also input as set in step S160 of the purge control routine of FIG.

When the data is input in this way, the lower limit energization time Tmin is set based on the smaller of the surge pressure Ps and the ejector relative pressure Pej (step S310). The lower limit energization time Tmin is the time required for the purge flow rate to reach linear with respect to the time (drive energization time) after the purge control valve 65 is opened. FIG. 9 shows an example of the relationship between the drive energization time and the purge flow rate. As shown in FIG. 9, the purge flow rate is non-linear with respect to the drive energization time until the drive energization time reaches the lower limit energization time Tmin. On the other hand, when the drive energization time exceeds the lower limit energization time Tmin, the purge flow rate becomes linear with respect to the drive energization time. Since this lower limit energization time Tmin is affected by the negative pressure acting on the purge control valve 65 (the smaller of the surge pressure Ps and the ejector relative pressure Pej), it acts on the purge control valve 65 in the embodiment. The relationship between the negative pressure (the smaller of the surge pressure Ps and the ejector relative pressure Pej) and the lower limit energization time Tmin is investigated in advance by experiments, etc., stored as a map for setting the lower limit energization time, and purge control is performed in the map. It was set by applying the negative pressure acting on the valve 65 and deriving it. FIG. 10 shows an example of a map for setting the lower limit energization time. In the embodiment, the lower limit energization time Tmin becomes longer as the negative pressure (the smaller of the surge pressure Ps and the ejector relative pressure Pej) acting on the purge control valve 65 is smaller (the absolute value is larger). Set.

Next, the larger of the open time and the lower limit energization time Tmin in the drive cycle Tprd obtained by applying the required duty Drq to the drive cycle Tprd of the purge control valve 65 is set as the open time Topn of the purge control valve 65 (step). S320). Then, the purge control valve 65 is opened and closed based on the opening time Topn of the purge control valve 65 (step S330), and this process is completed.

In the engine device 10 of the embodiment described above, when the surge pressure Ps becomes less than the threshold value Pref from the state where the upstream purge is dominant (purge flag Fp is a value 1), it is determined after the purge pressure Ps becomes less than the threshold value Pref. After the lapse of time, the purge flag Fp is set to a value of 0. Therefore, when the surge pressure Ps becomes less than the threshold value Pref from the state where the upstream purge is dominant, the same control parameters as when the upstream purge is dominant until a predetermined time elapses, for example, the target purge rate Rptg and the upper limit purge The purge control valve 65 is controlled using a rate Rplim or the like. Therefore, even if the purge from the first purge passage 62 and the purge from the second purge passage 63 are supplied in an overlapping manner immediately after the surge pressure Ps reaches the threshold value Pref or more and becomes less than the threshold value Pref, the downstream purge is dominant. Compared with the case where the control parameter is used, the purge amount from the first purge passage 62 is smaller, and it is possible to suppress the fuel injection control from becoming unstable.

Further, in the engine device 10 of the embodiment, since the lower limit energization time Tmin is set based on the smaller of the surge pressure Ps and the ejector relative pressure Pej, a more appropriate lower limit energization time Tmin can be set. , The opening time Topn of the purge control valve 65 can be set more appropriately.

In the engine device 10 of the embodiment, in the evaporative fuel processing device 50, the purge passage 60 is connected to the vicinity of the canister 56 of the introduction passage 52. However, it may be connected to the canister 56.

In the engine device 10 of the embodiment, the supercharger 40 is configured as a turbocharger in which a compressor 41 arranged in the intake pipe 23 and a turbine 42 arranged in the exhaust pipe 35 are connected via a rotating shaft 43. I made it. However, instead of this, the compressor driven by the engine 12 or the motor may be configured as a supercharger arranged in the intake pipe 23.

In the embodiment, the engine device 10 mounted on a general automobile or various hybrid automobiles is used. However, it may be in the form of an engine device mounted on a vehicle other than an automobile, or may be in the form of an engine device mounted on non-moving equipment such as construction equipment.

The correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the engine 12 corresponds to the "engine", the supercharger 40 corresponds to the "supercharger", the evaporated fuel processing device 50 corresponds to the "evaporated fuel processing device", and the electronic control unit 70 corresponds to the "evaporative fuel processing device". Corresponds to "control device".

Regarding the correspondence between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem, the invention described in the column of means for solving the problem in the examples is carried out. Since it is an example for specifically explaining the form for solving the problem, the elements of the invention described in the column of means for solving the problem are not limited. That is, the interpretation of the invention described in the column of means for solving the problem should be performed based on the description in the column, and the examples are the inventions described in the column of means for solving the problem. It is just a concrete example.

Although the embodiments for carrying out the present invention have been described above with reference to examples, the present invention is not limited to these examples, and various embodiments are used without departing from the gist of the present invention. Of course, it can be done.

The present invention can be used in the manufacturing industry of engine devices and the like.

10 engine device, 11 fuel tank, 11a pressure sensor, 12 engine, 14 crank shaft, 14a crank position sensor, 22 air cleaner, 23 intake pipe, 23a air flow meter, 23b, 23c, 27a pressure sensor, 24 bypass pipe, 25 intercooler , 26 Throttle valve, 26a Throttle position sensor, 27 Surge tank, 27b Temperature sensor, 28a Port injection valve, 28b In-cylinder injection valve, 29 Intake valve, 30 Combustion chamber, 31 Ignition plug, 32 Piston, 34 Exhaust valve, 35 Exhaust Pipe, 35a front air fuel ratio sensor, 35b rear air fuel ratio sensor, 36 bypass pipe, 37, 38 purification device, 40 supercharger, 41 compressor, 42 turbine, 43 rotating shaft, 44 waste gate valve, 45 blow-off valve, 50 evaporation Fuel processing equipment, 52 introduction passage, 53 open / close valve, 54 bypass passage, 54a, 54b branch, 55a, 55b relief valve, 55b relief valve, 56 canister, 57 open air passage, 58 air filter, 60 purge passage, 60a branch Point, 61 Supply passage, 62 1st purge passage, 63 2nd purge passage, 63a OBD sensor, 64 buffer part, 65 purge control valve, 65a purge control valve position sensor, 66 check valve, 67 check valve, 68 Circulation passage, 69 ejector, 70 electronic control unit.

Claims (1)

An engine that receives fuel from the fuel tank and has a throttle valve located in the intake pipe.
A supercharger having a compressor arranged on the upstream side of the throttle valve of the intake pipe, and
Evaporated fuel gas containing evaporated fuel generated in the fuel tank is branched into a first purge passage and a second purge passage connected to the downstream side of the throttle valve of the intake pipe and supplied to the intake pipe. An intake port is connected to a supply passage and a recirculation passage from between the compressor and the throttle valve of the intake pipe, and an exhaust port is connected to the upstream side of the intake pipe with respect to the compressor, and the second purge passage. An evaporative fuel treatment device having an ejector connected to a suction port and a purge control valve provided in the supply passage.
When the evaporated fuel gas is supplied to the intake pipe, the drive duty is set based on the fully open purge rate when the drive duty of the purge control valve is set to 100% and the required purge rate, and the purge control is performed. A control device that controls the valve and
It is an engine device equipped with
When the intake pressure on the downstream side of the throttle valve of the intake pipe is less than the threshold value, the control device determines that purging by the first purge passage is dominant and when the intake pressure is equal to or higher than the threshold value. In the dominant purge determination for determining that the purge by the second purge passage is dominant, when the intake pressure reaches from the threshold value or more to less than the threshold value, the second purge passage is used until a predetermined time elapses. It is determined that the purge is dominant, and the purge control valve is controlled using the determination result.
An engine device characterized by that.

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