JP2022015812A - Engine device - Google Patents

Abstract

To restrain air-fuel mixture injected from a port injection valve from being blown out from an intake passage to an exhaust passage.SOLUTION: An engine device includes an engine having a port injection valve for injecting fuel into an intake passage, and a supercharger having a compressor arranged in an intake pipe of the engine. The engine is controlled so that the fuel is injected from the port injection valve after an exhaust valve of the engine is closed when the engine is operated in a scavenge region. Thereby, air-fuel mixture injected from the port injection valve can be restrained from being blown out from the intake passage to an exhaust passage.SELECTED DRAWING: Figure 3

Description

The present invention relates to an engine device.

Conventionally, as an engine device of this type, a device including an internal combustion engine and a supercharger has been proposed (see, for example, Patent Document 1). In this engine device, when the operating region is in the scavenging region where the intake fresh air is blown from the intake valve to the exhaust valve, scavenging control for scavenging the inside of the cylinder of the internal combustion engine is executed.

Japanese Unexamined Patent Publication No. 2013-253298

In such an engine device, when fuel is injected into the intake passage from a port injection valve, when the engine is operated in a hydrocarbon region, a mixture of the injected fuel and air blows from the intake passage to the exhaust passage. Increased hydrocarbon emissions and catalyst temperature may occur.

The main object of the engine device of the present invention is to prevent the air-fuel mixture injected from the port injection valve from blowing through the intake passage to the exhaust passage.

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 with a port injection valve that injects fuel into the intake passage,
A turbocharger having a compressor arranged in the intake pipe of the engine, and
A control device that controls the engine and the turbocharger,
It is an engine device equipped with
When the engine is operated in the scavenging region, the control device controls the engine so that fuel is injected from the port injection valve after the exhaust valve of the engine is closed.
The gist is that.

In the engine device of the present invention, when the engine is operated in the scavenging region, the engine is controlled so that fuel is injected from the port injection valve after the exhaust valve of the engine is closed. As a result, it is possible to prevent the air-fuel mixture injected from the port injection valve from blowing through the intake passage to the exhaust passage. As a result, it is possible to suppress an increase in hydrocarbon emissions and an increase in catalyst temperature.

In the engine device of the present invention, the control device is to inject fuel from the port injection valve after the exhaust valve is closed when the engine is operated in the scavenging region and there is an overlap period. It may control the engine. Here, the "overlap period" is a period during which the intake valve and the exhaust valve of the engine are open.

In the engine device of the present invention, the engine has an in-cylinder injection valve for injecting fuel into the combustion chamber, and the control device injects fuel from the port injection valve when the engine is operated in the scavenging region. In the injection mode of injection, the engine may be controlled so that fuel is injected from the port injection valve after the exhaust valve is closed.

It is a block diagram which shows the outline of the structure of the engine apparatus 10 as an 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 processing routine executed by an electronic control unit 70.

Next, an embodiment 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 an 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, the engine 12, the supercharger 40, and the electronic control unit 70 as a control device are included. To prepare for.

The engine 12 is configured as an internal combustion engine that outputs power by using a fuel such as gasoline or light oil. The engine 12 has a port injection valve 28a for injecting fuel into an intake port and an in-cylinder injection valve 28b for injecting fuel into the cylinder. By having the port injection valve 28a and the in-cylinder injection valve 28b, the engine 12 can be operated in any one of the port injection mode, the in-cylinder injection mode, and the shared injection mode.

In the port injection mode, the air cleaned by the air cleaner 22 is sucked into the intake pipe 23 and passed through the intercooler 25, the throttle valve 26, and the surge tank 27 in this order. Then, fuel is injected from the port injection valve 28a attached to the downstream side of the surge tank 27 of the intake pipe 23, and the air and the fuel are mixed. Then, this air-fuel mixture is sucked into the combustion chamber 30 through the intake valve 29, and is explosively combusted by the electric sparks generated by the spark plug 31. Then, the reciprocating motion of the piston 32 pushed down by the energy generated by the explosive combustion is converted into the rotational motion of the crankshaft 14. In the in-cylinder injection mode, air is sucked into the combustion chamber 30 as in the port injection mode, and fuel is injected from the in-cylinder injection valve 28b attached to the combustion chamber 30 during the intake stroke or after reaching the compression stroke. Explosive combustion is obtained by electric sparks from the spark plug 31 to obtain rotational motion of the crank shaft 14. In the shared injection mode, fuel is injected from the port injection valve 28a when air is sucked into the combustion chamber 30, fuel is injected from the in-cylinder injection valve 28b in the intake stroke and the compression stroke, and the fuel is exploded by an electric spark from the spark plug 31. It is burned to obtain the rotational movement of the crankshaft 14. These injection modes are switched according to the operating state of the engine 12.

The exhaust gas discharged from the combustion chamber 30 to the exhaust pipe 35 via the exhaust valve 34 is discharged to the outside air via the purification devices 37 and 38 attached to the exhaust pipe 35. The purification devices 37 and 38 have catalysts (three-way catalysts) 37a and 38a for purifying harmful components of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx). The engine 12 has a variable valve timing mechanism (hereinafter referred to as "VVT mechanism") 50 capable of continuously changing the opening / closing timing of the intake valve 29 and the exhaust valve 34, respectively.

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

In the turbocharger 40, by adjusting the opening degree of the wastegate valve 44, the distribution ratio between the displacement flowing through the bypass pipe 36 and the displacement flowing through the turbine 41 is adjusted, and the rotational driving force of the turbine 41 is adjusted. Then, the amount of compressed air by the compressor 42 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 41. When the wastegate valve 44 is fully opened, the engine 12 operates in the same manner as a naturally aspirated engine without a supercharger 40.

Further, in the turbocharger 40, when the pressure on the downstream side of the compressor 42 of the intake pipe 23 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 42. 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 42 of 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 electronic control unit 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, a non-volatile flash memory, and an input / output port. , Equipped with a communication port. As shown in FIG. 2, signals from various sensors are input to the electronic control unit 70 via the input port.

The signals input to the electronic control unit 70 include, for example, a crank angle θcr from the crank position sensor 14a that detects the rotational position of the crankshaft 14 of the engine 12, and a water temperature (not shown) that detects the temperature of the cooling water of the engine 12. Examples include the cooling water temperature Tw from the sensor and the throttle opening TH from the throttle position sensor 26a that detects the opening degree of the throttle valve 26. Camposition θca from a camposition sensor (not shown) that detects the rotational position of the intake camshaft that opens and closes the intake valve 29 and the exhaust camshaft that opens and closes the exhaust valve 34 can also be mentioned. The intake air amount Qa from the air flow meter 23a installed on the upstream side of the compressor 42 of the intake pipe 23, the intake pressure Pin from the intake pressure sensor 23b installed on the upstream side of the compressor 42 of the intake pipe 23, and the intake air. The boost pressure Pc from the boost pressure sensor 23c attached between the compressor 42 of the pipe 23 and the intercooler 25 can also be mentioned. Surge pressure Ps from the surge pressure sensor 27a attached to the surge tank 27 and surge temperature Ts from the temperature sensor 27b attached to the surge tank 27 can also be mentioned. The air-fuel ratio AF from the air-fuel ratio sensor 39a attached to the upstream side of the purification device 37 of the exhaust pipe 35 and the oxygen signal O2 from the oxygen sensor 39b attached between the purification devices 37 and 38 of the exhaust pipe 35 are also mentioned. be able to. The atmospheric pressure Pout from the atmospheric pressure sensor 71 and the outside air temperature Tout from the outside air temperature sensor 72 can also be mentioned.

Various control signals are output from the electronic control unit 70 via the output port. The signals output from the electronic control unit 70 include, for example, a control signal to the throttle valve 26, a control signal to the port injection valve 28a and the in-cylinder injection valve 28b, a control signal to the spark plug 31, and a VVT mechanism 50. The control signal of can be mentioned. A control signal to the wastegate valve 44 and a control signal to the blow-off valve 45 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 has a load factor (air actually sucked in one cycle with respect to 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. Volume ratio of) 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, the port injection valve 28a, and the like. Fuel injection control that controls the fuel injection amount from the in-cylinder injection valve 28b, VVT control that controls the VVT mechanism 50, ignition control that controls the ignition timing of the ignition plug 31, and supercharging that controls the opening degree of the wastegate valve 44. Perform control and so on. As described above, when the wastegate valve 44 is fully opened, the engine 12 operates in the same manner as a naturally aspirated engine without a supercharger 40.

The fuel injection control sets the execution injection mode from the port injection mode, the in-cylinder injection mode, and the shared injection mode based on the engine 12 rotation speed Ne and the load factor KL, and is based on the intake air amount Qa and the execution injection mode. The target injection amounts Qfp * and Qfd * of the port injection valve 28a and the in-cylinder injection valve 28b are set so that the air-fuel ratio AF becomes the target air-fuel ratio AF * (for example, the theoretical air-fuel ratio), and the target injection amount Qfp *, This is performed by controlling the port injection valve 28a and the in-cylinder injection valve 28b using Qfd *.

In VVT control, the target opening / closing timing VTin * of the intake valve 29 and the target opening / closing timing VTex * of the exhaust valve 34 are set based on the required load factor KL * of the engine 12, and the opening / closing timing VTin of the intake valve 29 is the target opening / closing timing. This is performed by controlling the VVT mechanism 50 so that the timing is VTin *.

Next, the operation of the engine device 10 of the embodiment configured in this way, particularly the operation when setting the start time of the fuel injection from the port injection valve 28a will be described. The in-cylinder injection valve 28b basically starts fuel injection after the exhaust valve 34 is closed. FIG. 3 is a flowchart showing an example of a processing routine executed by the electronic control unit 70. This routine is executed repeatedly (for example, every predetermined angle (for example, 720 degrees) of the crank angle θcr) while the engine 12 is being operated in the port injection mode or the shared injection mode.

When the processing routine of FIG. 3 is executed, the electronic control unit 70 first inputs data such as surge pressure Ps and atmospheric pressure Pout (step S100). Here, a value detected by the surge pressure sensor 27a is input as the surge pressure Ps. The value detected by the atmospheric pressure sensor 71 is input to the atmospheric pressure Pout.

When the data is input in this way, the surge pressure Ps is compared with the atmospheric pressure Pout (step S110), and it is determined whether or not there is an overlap period (step S120). Here, the "overlap period" is a period during which the intake valve 29 and the exhaust valve 34 of the engine 12 are open. The comparison in step S110 is performed to determine whether the operation of the engine 12 is within the scavenging region. When the engine 12 is in the scavenging region and during the overlap period, the pressure of the intake pipe 23 becomes equal to or higher than the pressure of the exhaust pipe 35, and when fuel is injected from the port injection valve 28a or the in-cylinder injection valve 28b, the injected fuel is combined with the injected fuel. Scavenging may occur in which the air-fuel mixture blows from the intake pipe 23 or the combustion chamber 30 to the exhaust pipe 35, resulting in an increase in hydrocarbon emissions or a rise in the temperature of the catalyst. Here, the pressure of the exhaust pipe 35 can be considered to be equal to the atmospheric pressure. Therefore, in an environment where the atmospheric pressure is low, such as in the highlands, the operation of the engine 12 is more likely to enter the scavenging region than in a normal atmospheric pressure environment. The determination in step S120 can be performed by examining the opening / closing timing of the intake valve 29 and the exhaust valve 34 in the VVT mechanism 50.

When the surge pressure Ps is less than the atmospheric pressure Pout in step S110, it is determined that the operation of the engine 12 is not within the scavenging region, and the fuel injection start timing of the port injection valve 28a is set so that the fuel is injected at the normal timing. (Step S130), this routine is terminated. When the surge pressure Ps is equal to or higher than the atmospheric pressure Pout in step S110 and there is no overlap period in step S120, it is determined that blow-by does not occur from the intake pipe 23 to the exhaust pipe 35 although it is in the scavenging region, and the port injection valve 28a The normal start time is set as the start time of fuel injection (step S130), and this routine is terminated. Here, the "normal start time" is set as the fuel injection start time of the port injection valve 28a in which the engine 12 is efficiently operated.

When the surge pressure Ps is equal to or higher than the atmospheric pressure Pout in step S110 and there is an overlap period in step S120, the fuel injection start time of the port injection valve 28a is set to the closing time of the exhaust valve 34 or a slightly later time. The setting (step S140) is performed, and this routine is terminated. As a result, when the engine 12 is operated in the scavenging region and there is an overlap period, the air-fuel mixture injected from the port injection valve 28a is blown from the intake pipe 23 to the exhaust pipe 35. It can be suppressed. As a result, it is possible to suppress an increase in hydrocarbon emissions and an increase in catalyst temperature.

In the engine device 10 of the above-described embodiment, when the engine 12 is operated in the scavenging region, the engine is controlled so that fuel is injected from the port injection valve 28a after the exhaust valve 34 of the engine 12 is closed. As a result, it is possible to prevent the air-fuel mixture injected from the port injection valve 28a from blowing through the intake pipe 23 to the exhaust pipe 35. As a result, it is possible to suppress an increase in hydrocarbon emissions and an increase in catalyst temperature.

In the engine device 10 of the embodiment, when the surge pressure Ps from the surge pressure sensor 27a is equal to or higher than the atmospheric pressure Pout, it is determined that the operation of the engine 12 is within the scavenging region. However, when the boost pressure Pc from the boost pressure sensor 23c is equal to or higher than the atmospheric pressure Pout, it may be determined that the operation of the engine 12 is within the scavenging region.

Although the engine device 10 of the embodiment is provided with the VVT mechanism 50, it may not be provided with the VVT mechanism. In this case, since the presence or absence of the overlap period does not change, the processing of step S120 may not be executed in the processing routine of FIG. 3 (the presence or absence of a stairwell is determined only by the processing of step S110).

In the engine device 10 of the embodiment, the engine 12 has a port injection valve 28a and an in-cylinder injection valve 28b as fuel injection valves. However, it may have only the port injection valve 28a as the fuel injection valve.

In the engine device 10 of the embodiment, the supercharger 40 is configured as a turbocharger in which a turbine 41 arranged in an exhaust pipe 35 and a compressor 42 arranged in an intake pipe 23 are connected via a connecting shaft 43. I made it. However, 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 is mounted on a general automobile or various hybrid automobiles. However, it may be mounted on a vehicle other than an automobile, or may be mounted on non-moving equipment such as construction equipment.

The correspondence between the main elements of the embodiment 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", and the electronic control unit 70 corresponds to the "control device".

As for 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 problems of the examples is carried out. Since it is an example for specifically explaining the mode 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 the embodiments, the present invention is not limited to these examples, and the present invention is not limited to these embodiments, 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 unit, 12 engine, 14 crank shaft, 14a crank position sensor, 22 air cleaner, 23 intake pipe, 23a air flow meter, 23b intake pressure sensor, 23c supercharging pressure sensor, 24 bypass pipe, 25 intercooler, 26 throttle valve, 26a Throttle position sensor, 27 surge tank, 27a surge pressure sensor, 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, 36 bypass pipe, 37,38 purification device, 37a, 38a catalyst, 39a air fuel ratio sensor, 39b oxygen sensor, 40 turbocharger, 41 turbine, 42 compressor, 43 connecting shaft, 44 waste gate valve, 45 blow-off valve, 70 Electronic control unit, 71 atmospheric pressure sensor, 72 outside temperature sensor.

Claims (1)

An engine with a port injection valve that injects fuel into the intake passage,
A turbocharger having a compressor arranged in the intake pipe of the engine, and
A control device that controls the engine and the turbocharger,
It is an engine device equipped with
When the engine is operated in the scavenging region, the control device controls the engine so that fuel is injected from the port injection valve after the exhaust valve of the engine is closed.
Engine equipment.

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