JP2021143613A - Fuel injection device - Google Patents

Abstract

To sufficiently promote gasification of injected fuel even when intake air has a low temperature.SOLUTION: A fuel injection device includes an injector 26 for injecting fuel into an intake port 22 from which intake air is sucked. The fuel injection device introduces a gas of which temperature is higher than the intake air in the vicinity of an injection port 26a of the injector 26.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fuel injection device including an injector for injecting fuel into an intake port.

Conventionally, a fuel injection device including an injector has been known. According to Patent Document 1, when the engine is cold and the intake air temperature is equal to or lower than a predetermined temperature, the EGR control means recirculates a part of the exhaust gas to the intake system, and the injector has a fuel spray between the electrodes of the spark plug. An in-cylinder injection engine having a first injection port for injecting fuel so as to be close to each other with a predetermined distance and a second injection port for injecting fuel on the piston side as compared with the first injection port. Exhaust gas recirculation devices are disclosed. In Patent Document 1, a part of high-temperature exhaust gas is allowed to flow into the intake air to raise the temperature of the gas flowing into the engine and maintain the combustion chamber in a state in which the injected fuel is easily vaporized.

Japanese Unexamined Patent Publication No. 2008-18807

On the other hand, a fuel injection device including an injector that injects fuel into an intake port having a structure different from that of Patent Document 1 has a problem that vaporization of the injected fuel is not sufficiently promoted when the intake air is at a low temperature. If the vaporization of the injected fuel is not sufficiently promoted, the fuel may adhere to the intake port in a liquid state, and the liquid fuel may flow into the fuel chamber, and PN (PM (Particulate matter) particles). Number) may increase.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to sufficiently promote the vaporization of the injected fuel even when the intake air is at a low temperature.

The present invention is a fuel injection device including an injector for injecting fuel into an intake port into which intake air is sucked, and introduces a gas having a temperature higher than that of the intake air in the vicinity of an injection port of the injector. It is a feature.

According to the present invention, the vaporization of the injected fuel can be sufficiently promoted even when the intake air is at a low temperature.

FIG. 1 is a diagram showing an example of the configuration of the fuel injection device according to the first embodiment. FIG. 2 is a flowchart showing an example of the operation of the fuel injection device. FIG. 3 is a diagram showing an example of the configuration of the fuel injection device according to the second embodiment. FIG. 4 is a flowchart showing an example of the operation of the fuel injection device. FIG. 5 is a diagram showing a modified example of the EGR injection control valve. FIG. 6 is a diagram showing a modified example of the EGR injection control valve.

In the embodiment of the present invention, the fuel injection device includes an injector 26 that injects fuel into the intake port 22 into which the intake air is sucked, and a gas having a temperature higher than that of the intake air is injected into the injection port 26a of the injector 26. Introduce in the vicinity. When the high-temperature gas mixes with the intake air, the temperature of the intake air in the vicinity of the injection port 26a of the injector 26 rises. Therefore, even when the intake air is at a low temperature, the temperature of the intake air rises, so that the vaporization of the fuel injected by the injector 26 can be sufficiently promoted.

Hereinafter, examples of the fuel injection device according to the present invention will be described with reference to the drawings.
<First Example>
FIG. 1A is a diagram showing a configuration of a fuel injection device mounted on the vehicle 10 according to the first embodiment. FIG. 1A is a simplification for the sake of explaining the technique of the present disclosure for convenience of explanation, and it is assumed that the configuration normally provided by the vehicle is provided even if it is not shown.

The vehicle 10 includes an engine 20. The engine 20 is an internal combustion engine and burns a mixture of fuel (for example, gasoline fuel) and intake air in a combustion chamber 21. Due to the combustion of the air-fuel mixture, the piston reciprocates in the cylinder of the engine 20, and the reciprocating motion of the piston is converted into the rotational motion of the crankshaft. The rotation of the crankshaft is transmitted to the drive wheels via the power transmission mechanism, so that the vehicle 10 travels.

Further, the engine 20 is provided with an intake port 22 leading to the combustion chamber 21 on the upstream side (intake side) of the combustion chamber 21. An intake manifold 24 is connected to the intake port 22. A throttle body, an air cleaner, and the like are connected to the upstream side (intake side) of the intake manifold 24. Therefore, the intake air that has been cleaned by the air cleaner and whose amount has been adjusted by the throttle body is sucked into the intake port 22 through the intake manifold 24. The intake manifold 24 is provided with a temperature sensor 25 that detects the temperature of the intake air. The intake port 22 is provided with an injector 26 that forms a part of the fuel injection device. The injector 26 injects the fuel pumped from the fuel tank by the fuel pump into the intake port 22. The injector 26 is arranged so that the injection port faces the combustion chamber 21 side. The injector 26 controls the amount of fuel injected based on the amount of intake air and the like.

Further, the engine 20 is provided with an exhaust port 27 leading to the combustion chamber 21 on the downstream side (exhaust side) of the combustion chamber 21. An exhaust pipe 28 is connected to the exhaust port 27. Further, a catalytic converter 29 is connected in the middle of the exhaust pipe 28. The catalytic converter 29 purifies harmful exhaust components in the exhaust gas. Therefore, the exhaust gas from the combustion chamber 21 of the engine 20 is purified by the catalytic converter 29 through the exhaust port 27 and the exhaust pipe 28 and exhausted to the outside.

Further, the vehicle 10 is provided with an exhaust gas recirculation device, so-called EGR (exhaust gas recirculation), which re-intakes a part of the exhaust gas after combustion in order to reduce nitrogen oxides in the exhaust gas and improve fuel efficiency. Specifically, the exhaust gas recirculation device has an EGR gas pipe 31 and an EGR valve 32. The EGR gas pipe 31 is arranged between the downstream side (exhaust side) of the catalytic converter 29 and the intake manifold 24 of the exhaust pipe 28. The EGR gas pipe 31 corresponds to an example of the second EGR gas passage. Therefore, a part of the exhaust gas purified by the catalytic converter 29 returns to the intake manifold 24 through the EGR gas pipe 31. Here, among the exhaust gas, the exhaust gas passing through the EGR gas pipe 31 is referred to as an external EGR gas. The EGR valve 32 adjusts the amount of external EGR gas flowing into the intake manifold 24. When the EGR valve 32 is opened, the external EGR gas flows into the intake manifold 24. On the other hand, when the EGR valve 32 is closed, the external EGR gas does not flow into the intake manifold 24. The opening and closing of the EGR valve 32 is controlled based on the intake air amount.

Further, in the vehicle 10 of the present embodiment, in order to sufficiently promote the vaporization of the fuel injected by the injector 26 even when the intake air is low temperature, a gas having a temperature higher than that of the intake air is injected into the injection port of the injector 26. It has a structure that can be introduced in the vicinity of. Specifically, the vehicle 10 of this embodiment includes a bypass pipe 35 and an EGR injection control valve 36.
FIG. 1B is an enlarged view of the periphery of the bypass pipe 35 and the EGR injection control valve 36, and is an enlarged view of the region A shown in FIG. 1A.

The bypass pipe 35 is arranged between the intake port 22 and the EGR gas pipe 31. The bypass pipe 35 corresponds to an example of the first EGR gas passage. The bypass pipe 35 introduces the external EGR gas into the intake port 22 without passing through the intake manifold 24. In the bypass pipe 35, one opening 35a is provided in the intake port 22. Here, the opening 35a is located in the vicinity of the injection port 26a of the injector 26. Specifically, the opening 35a is provided at a position facing the injection port 26a of the injector 26. Further, the opening 35a is provided at a position downstream (exhaust side) from the position where the injector 26 is attached. Further, the opening 35a is provided in a range in which fuel is injected from the injection port 26a of the injector 26. Further, the bypass pipe 35 is provided at a position where the other opening 35b is located downstream of the EGR valve 32 in the EGR gas pipe 31, that is, between the EGR valve 32 and the intake manifold 24 in the EGR gas pipe 31. ..

The EGR injection control valve 36 adjusts the amount of external EGR gas to be injected into the intake port 22 through the bypass pipe 35. When the EGR injection control valve 36 is opened while the EGR valve 32 is open, the external EGR gas is injected into the intake port 22 through the bypass pipe 35. Since the external EGR gas is higher than the temperature of the intake air, the temperature of the intake air in the vicinity of the injection port 26a of the injector 26 can be raised by mixing with the intake air. On the other hand, when the EGR injection control valve 36 is closed, the external EGR gas is not injected into the intake port 22. The opening and closing of the EGR injection control valve 36 is controlled based on the temperature of the intake air.

The EGR injection control valve 36 is provided in the opening 35a on one side of the bypass pipe 35. As shown in FIG. 1 (b), the EGR injection control valve 36 opens when it separates from the opening 35a. When the EGR injection control valve 36 is opened, the external EGR gas is injected into the intake port 22 through the gap between the opening 35a and the EGR injection control valve 36 as shown by the arrow. On the other hand, the EGR injection control valve 36 closes when it comes into contact with the opening 35a. By closing the EGR injection control valve 36, the gap between the opening 35a and the EGR injection control valve 36 is eliminated, and the external EGR gas is not injected into the intake port 22.

Further, the vehicle 10 includes a control unit 40 that controls the engine 20 and related equipment. For the control unit 40, for example, an ECU (Electrical Control Unit) can be used. The control unit 40 controls related devices such as the injector 26, the EGR valve 32, and the EGR injection control valve 36. Specifically, the control unit 40 controls the amount of fuel injected from the injector 26 based on the amount of intake air or the like. Further, the control unit 40 controls the opening and closing of the EGR valve 32 based on the intake air amount. Further, the control unit 40 controls the opening and closing of the EGR injection control valve 36 based on the temperature of the intake air.

In the vehicle 10 configured as described above, the control unit 40 controls the EGR valve 32 and the EGR injection control valve 36 so that the vaporization of the injected fuel can be sufficiently promoted even when the intake air is at a low temperature. do.
Hereinafter, the operation of the fuel injection device according to the first embodiment will be described with reference to the flowchart of FIG. The flowchart of FIG. 2 is realized by the control unit 40 executing a program stored in the memory. The flowchart of FIG. 2 is started when the engine 20 is started.

In S10, the control unit 40 acquires information on the temperature of the intake air. Specifically, the control unit 40 acquires information on the temperature of the intake air of the intake manifold 24 detected by the temperature sensor 25.
In S11, the control unit 40 determines the amount of external EGR gas introduced from the EGR injection control valve 36 into the intake port 22 based on the temperature of the intake air. Specifically, the control unit 40 determines the amount of the external EGR gas so that the lower the temperature of the intake air, the larger the amount of the external EGR gas to be introduced. Further, when the temperature of the intake air is equal to or higher than a predetermined temperature, the control unit 40 determines the amount of the external EGR gas to be introduced to 0. Information indicating the correspondence between the temperature of the intake air and the amount of the external EGR gas is stored in the memory of the control unit 40 in advance. The information is information in which the amount of external EGR gas capable of raising the temperature of the intake air to a predetermined temperature when mixed with the intake air is made to correspond to the temperature of the intake air.

In S12, the control unit 40 determines the opening degree of the EGR injection control valve 36 based on the determined amount of the external EGR gas. Specifically, the control unit 40 determines that the opening degree of the EGR injection control valve 36 increases as the amount of the external EGR gas increases. In the memory of the control unit 40, information indicating the correspondence relationship between the amount of the external EGR gas and the opening degree of the EGR injection control valve 36 is stored in advance.

In S13, the control unit 40 determines whether or not the EGR valve 32 is closed. When the EGR valve 32 is closed, the process proceeds to S14, and when the EGR valve 32 is opened, the process proceeds to S15.
In S14, the control unit 40 opens the EGR valve 32. In this embodiment, since the other opening 35b of the bypass pipe 35 is provided at a position between the EGR valve 32 and the intake manifold 24 in the EGR gas pipe 31, the EGR valve 32 remains closed. The external EGR gas does not flow from the EGR gas pipe 31 into the bypass pipe 35, and the external EGR gas cannot be injected from the EGR injection control valve 36 into the intake port 22. By opening the EGR valve 32 in S14, the external EGR gas can flow from the EGR gas pipe 31 into the bypass pipe 35.

In S15, the control unit 40 controls the opening and closing of the EGR injection control valve 36. Specifically, the control unit 40 controls the EGR injection control valve 36 so that the opening degree is determined in S12. Therefore, by opening the EGR injection control valve 36 so as to have a determined opening degree, the external EGR gas is injected from the EGR injection control valve 36, and the injected external EGR gas is discharged from the injection port 26a of the injector 26. Introduced in the vicinity. When the external EGR gas mixes with the intake air, the temperature of the intake air in the vicinity of the injection port 26a of the injector 26 rises. Therefore, even when the intake air is at a low temperature, the temperature of the intake air is raised by the external EGR gas, so that the vaporization of the fuel injected by the injector 26 can be sufficiently promoted.

The control unit 40 repeats the processes from S10 to S15 after the engine 20 is started. The temperature of the intake air is low when the engine 20 is cooled, and increases as the temperature of each component rises when the engine 20 is warmed up. Therefore, the control unit 40 detects the temperature of the cooling water of the engine 20, repeats the processes from S10 to S15 when the temperature is lower than the constant temperature, and processes S10 to S15 when the temperature is above the constant temperature. May not be done.

As described above, according to the present embodiment, by introducing the external EGR gas having a temperature higher than that of the intake air in the vicinity of the injection port 26a of the injector 26, the intake air is injected even when the intake air is low temperature. The vaporization of fuel can be sufficiently promoted. By promoting the vaporization of the fuel in this way, it is possible to reduce the PN because the inflow of the liquid fuel into the fuel chamber is suppressed. Further, by promoting the vaporization of the fuel, the thermal efficiency in a low temperature environment can be improved.

Further, according to the present embodiment, the existing exhaust gas recirculation device can be used by introducing the external EGR gas as a gas having a temperature higher than that of the intake air, so that it is possible to use the existing exhaust gas recirculation device without adding a new device. It is possible to promote the vaporization of fuel.
Further, according to the present embodiment, since one opening 35a of the bypass pipe 35 is provided at a position facing the injection port 26a of the injector 26, the external EGR gas immediately after being introduced into the intake port 22 is the injector 26. It is possible to raise the temperature of the wall surface by contacting the wall surface where the fuel injected from the vehicle hits. Therefore, even if the fuel injected from the injector 26 adheres to the wall surface in a liquid state, the vaporization of the fuel can be promoted.

Further, according to this embodiment, the other opening 35b of the bypass pipe 35 is provided at a position in the EGR gas pipe 31 between the EGR valve 32 and the intake manifold 24. Therefore, since the external EGR gas can be branched and flowed to the intake manifold 24 and the bypass pipe 35 at two locations, the amount of condensed water generated by the intake manifold 24 is compared with the case where the external EGR gas is flown to one location of the intake manifold 24. Can be reduced. By reducing the amount of condensed water, it is possible to suppress the failure of the engine 20 and the deterioration of combustion that occur when the condensed water infiltrates into the combustion chamber 21.

Further, according to the present embodiment, the control unit 40 increases or decreases the amount of the external EGR gas introduced in the vicinity of the injection port 26a of the injector 26 based on the temperature of the intake air. Therefore, the amount of external EGR gas introduced in the vicinity of the injection port 26a of the injector 26 can be adjusted accurately.

<Second Example>
Next, a second embodiment will be described. FIG. 3 is a diagram showing a configuration of a fuel injection device mounted on the vehicle 50 according to the second embodiment. In FIG. 3, the same configurations as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted as appropriate.
The vehicle 50 of this embodiment includes a bypass pipe 45 and an EGR injection control valve 36. The other opening of the bypass pipe 45 of this embodiment is provided in the EGR gas pipe 31 on the upstream side of the EGR valve 32, that is, at a position between the EGR valve 32 and the exhaust pipe 28 in the EGR gas pipe 31. Be done. In this way, by providing the other opening of the bypass pipe 45 at a position between the EGR valve 32 and the intake manifold 24 in the EGR gas pipe 31, EGR injection is performed even when the EGR valve 32 is closed. External EGR gas can be introduced into the intake port 22 from the control valve 36.

Hereinafter, the operation of the fuel injection device according to the present embodiment will be described with reference to the flowchart of FIG. The same processing as the flowchart of FIG. 2 will be omitted as appropriate.
In S20, the control unit 40 acquires information on the temperature of the intake air. This process is the same as that of S10.
In S21, the control unit 40 determines the amount of external EGR gas introduced from the EGR injection control valve 36 into the intake port 22 based on the temperature of the intake air. This process is the same as S11.

In S22, the control unit 40 determines the opening degree of the EGR injection control valve 36 based on the determined amount of the external EGR gas. This process is the same as that of S12.
In S23, the control unit 40 controls the opening and closing of the EGR injection control valve 36. This process is the same as S15. By opening the EGR injection control valve 36 so as to have a determined opening degree, the external EGR gas injected by the EGR injection control valve 36 is introduced in the vicinity of the injection port 26a of the injector 26. Therefore, even if the temperature of the intake air is low, the temperature of the intake air is raised by the external EGR gas, so that the vaporization of the fuel injected by the injector 26 can be sufficiently promoted.

According to this embodiment, the other opening of the bypass pipe 45 is provided at a position in the EGR gas pipe 31 between the EGR valve 32 and the exhaust pipe 28. Therefore, regardless of whether the EGR valve 32 is open or closed, the external EGR gas can be introduced in the vicinity of the injection port 26a of the injector 26, and the processing by the control unit 40 can be simplified.

Although the examples according to the present invention have been described above, the present invention is not limited to the above-mentioned examples, and changes can be made within the scope of the present invention.
In each of the above-described embodiments, the case where the external EGR gas is introduced as a gas having a temperature higher than that of the intake air has been described, but the case is not limited to this case. For example, as an example of a gas having a temperature higher than that of the intake air, a part of the intake air is branched and heated by a heater provided in the vehicle, and the heated intake air is introduced in the vicinity of the injection port 26a of the injector 26. May be good.

Further, in each of the above-described embodiments, the case where the EGR injection control valve 36 opens and closes by moving away from or in contact with the openings 35a of the bypass pipes 35 and 45 has been described, but the case is not limited to this case and is more than the intake air. Any structure may be used as long as it can introduce a gas having a high temperature in the vicinity of the injection port 26a of the injector 26.
For example, the EGR injection control valve 56 shown in FIG. 5 is provided in one opening 35a of the bypass pipe 35 and opens and closes by rotating around the rotation shaft 57 in the direction of the arrow. Further, for example, the EGR injection control valve 66 shown in FIG. 6 is provided in the other opening 35b of the bypass pipe 35 and opens and closes by rotating around the rotation shaft 67 in the arrow direction. Even with such a rotary valve, the control unit 40 can increase or decrease the amount of external EGR gas introduced in the vicinity of the injection port 26a of the injector 26 based on the temperature of the intake air.

Further, in each of the above-described embodiments, the case where the fuel is gasoline fuel has been described, but the present invention is not limited to this case, and petroleum-based fuels such as heavy oil, light oil, and kerosene may be used, and alcohols may be used. , Oils and fats may be used.

10, 50: Vehicle 20: Engine 21: Fuel chamber 22: Intake port 24: Intake manifold 25: Temperature sensor 26: Injector injection port 26a 31: EGR gas piping (second EGR gas passage) 32: EGR valve 35, 45 : Bypass piping (first EGR gas passage) 36, 56, 66: EGR injection control valve 40: Control unit

Claims (5)

A fuel injection device equipped with an injector that injects fuel into an intake port into which intake air is sucked.
A fuel injection device characterized in that a gas having a temperature higher than that of the intake air is introduced in the vicinity of the injection port of the injector. The fuel injection device according to claim 1, wherein the external EGR gas is introduced in the vicinity of the injection port of the injector. A first EGR gas passage for introducing the external EGR gas into the intake port is provided.
The fuel injection device according to claim 2, wherein one opening of the first EGR gas passage is provided at a position facing the injection port of the injector. A second EGR gas passage for introducing the external EGR gas into the intake manifold, and
An EGR valve provided in the middle of the second EGR gas passage is provided.
The third aspect of claim 3, wherein the other opening of the first EGR gas passage is provided at a position between the EGR valve and the intake manifold in the second EGR gas passage. Fuel injection device. A control unit for controlling the amount of the external EGR gas introduced in the vicinity of the injection port of the injector is provided.
The control unit according to any one of claims 2 to 4, wherein the control unit increases or decreases the amount of the external EGR gas introduced in the vicinity of the injection port of the injector based on the temperature of the intake air. Fuel injector.

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