JPH062549A - Fuel supply device for engine - Google Patents

Abstract

PURPOSE:To promote fuel cooling so as to attain a high output in an engine by arranging injectors in two intake passages independently connected to a combustion chamber, and providing a flow speed increasing means for increasing an intake flow speed in the secondary side intake passage. CONSTITUTION:Primary and secondary side injectors 5, 6 are respectively arranged in a primary side intake passage 22 and a secondary side intake passage inependently connected to a combustion chamber 1 of an engine 1. A control valve 7 for throttling a passage area of the primary side intake passage 22 is arranged in a position of the downstream from a primary side throttle valve 3 of the primary side intake passage 22. This control valve 7 is a flow speed increasing means and driven by a pressure responding actuator 32. An opening of the control valve 7 is regulated by a solenoid valve 33. The passage area of the primary side intake passage 22 is throttled only for a predetermined time at transfer time of an operation region at acceleration time by a control signal from a control unit 10. Thus by promoting fuel cooling, a high output of the engine can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has injectors arranged in two intake passages that are independently communicated with an engine combustion chamber, and in a low engine speed or low load operation region of an engine, only one injector is used for fuel injection. The present invention relates to a fuel supply device for an engine which supplies fuel and simultaneously supplies fuel from both injectors in a high rotation and high load operation region.

[0002]

2. Description of the Related Art Conventionally, in an engine, from the viewpoint of promoting vaporization and atomization of fuel throughout the entire operating range, or promoting mixing of intake air and fuel, the intake passage is provided with a primary intake passage and a secondary intake passage. In a low rotation or low load operation region where the intake air amount is small, the intake flow rate is maintained properly by introducing the intake air only in the primary side intake passage, and the intake air amount is high and the rotation speed is high. In the operating region, a large amount of intake air is simultaneously introduced from both the primary side intake passage and the secondary side intake passage.

On the other hand, one of the fuel supply systems in the engine having the primary side intake passage and the secondary side intake passage as described above is provided with an injector for each intake passage, and each of these injectors is provided. It is known that the intake passage is operated in correspondence with the operation (that is, the operating state of the engine).

By the way, in the case where the injectors are arranged in the respective intake passages which are selectively used in accordance with the operating state as described above, as shown in FIG. And a switching line corresponding to the engine load, an operating region on the low rotation side or low load side of this switching line is set as the first operating region, and an operating region on the high rotation / high load side of the switching line is set. This is the second operation area. Then, in this first operating region, intake air is introduced only from the primary side intake passage, and fuel is supplied from the primary side injector into this primary side intake passage, and in the second operating region it is connected to the primary side intake passage. The intake air is introduced from both of the secondary intake passages, and the fuel is supplied from the primary injectors and the secondary injectors into the corresponding intake passages.

However, in such a fuel supply device, when the operating region shifts from the first operating region to the second operating region with the acceleration of the engine as shown by the arrow curve in FIG. The introduction of intake air from the secondary side intake passage and the fuel supply from the secondary side injector are started at the same time with the transition to, but when the intake introduction and fuel supply from this secondary side are started. Until then, no fuel was supplied to the secondary side intake passage, so there was almost no residual fuel (for example, fuel that had adhered to the passage wall and remained), and therefore, there was no transfer of fuel to the second operation region at the same time as the transition to the second operating region. Even if fuel is supplied from the secondary injector into the primary intake passage, it takes a relatively long time to actually reach the combustion chamber (i.e., there is a delay in fuel transportation), and the supplied fuel is The entire amount of the fuel is not immediately sucked into the combustion chamber side, but a part of the fuel remains in the passage as the adhered fuel, and the fuel amount is substantially reduced accordingly. The air-fuel ratio becomes lean, and a shock will occur due to a reduction in engine output.

As a technique for solving such a problem, for example, Japanese Patent Publication No. 2-14974 discloses a fuel supply mode in which fuel is supplied only from the primary side injector to both the primary side injector and the secondary side injector. When the fuel supply from the secondary injector is changed to the fuel supply from the secondary injector by appropriately increasing the fuel injection amount of the primary injector which has been continuously supplied fuel before that. It is known that a shock is avoided in advance by compensating for a primary decrease in the air-fuel ratio due to a transportation delay.

[0007]

However, according to such a fuel amount increasing method, it is possible to avoid the occurrence of a shock at the time of switching the fuel supply mode at the time of acceleration, but on the other hand, as described below. For some reason, problems such as an increase in fuel consumption or a deterioration in drivability due to fluctuations in the air-fuel ratio may occur. That is, even if there is a fuel transportation delay immediately after the fuel supply from the secondary injector is started, the supplied fuel amount itself does not decrease. It will be introduced. Therefore, when the fuel delayed in transportation is actually introduced into the combustion chamber, the increased fuel becomes excessive with respect to the required fuel amount of the engine, resulting in an increase in the fuel consumption amount or a change in the air-fuel ratio. Will lead to.

Therefore, in the present invention, the shock generation during acceleration is surely suppressed without increasing the fuel consumption amount or the fluctuation of the air-fuel ratio, and at the same time, the cooling of the fuel is promoted to achieve the high output of the engine. The present invention is designed to provide a fuel supply system for an engine that can be used.

[0009]

According to the invention of claim 1, as a concrete means for solving such a problem in the invention of the present application, in the invention of claim 1, a primary side intake passage and a secondary passage which communicate independently with the combustion chamber of the engine, respectively. The primary side injector and the secondary side injector are respectively arranged in the side intake passages, and fuel is supplied only by the primary side injector in the low rotation or low load operation region of the engine, and in the high rotation and high load operation region. In a fuel supply device for an engine, which is configured to simultaneously supply fuel from both the primary side injector and the secondary side injector, the operating region of the engine is from the operating region in which only the primary side injector operates to the primary side injector. -The secondary side injector is operated for a predetermined time when the operating range in which both the secondary side injector and the secondary injector operate. Ejector - is characterized by including the flow rate increasing means to increase the intake flow rate of the deployed the secondary side intake passage.

According to a second aspect of the present invention, in the engine fuel supply apparatus according to the first aspect, the flow velocity increasing means is a control valve for reducing the passage area of the primary side intake passage in which the primary side injector is arranged. It is characterized by being configured with.

According to the invention of claim 3, claim 1 or 2
The fuel supply device for an engine as described above is characterized in that the secondary injector is arranged at a position farther from the combustion chamber than the primary injector.

[0012]

With each of the inventions of the present application, the following effects can be obtained by adopting such a configuration.

According to the first aspect of the present invention, as the engine accelerates, its operating range is such that fuel is supplied only from the primary injector, and fuel is supplied simultaneously from both the primary injector and the secondary injector. When the operation range is changed to the above, the flow velocity increasing means is operated for a predetermined time thereafter to increase the intake flow velocity in the secondary side intake passage provided with the secondary side injector. As a result, the fuel that is injected and supplied from the secondary injector into the secondary intake passage rides on the high-velocity intake flow, and almost does not adhere to the passage wall of the secondary intake passage. The entire amount is transported to the combustion chamber side of the engine quickly, and the conventional fuel transport delay is suppressed as much as possible.

According to the second aspect of the present invention, the control valve disposed in the primary side intake passage narrows the passage area of the primary side intake passage to reduce the amount of intake air flowing through the primary side intake passage. The amount of intake air flowing through the secondary intake passage side is increased and the flow velocity is increased, whereby the above-mentioned action is secured.

According to the third aspect of the invention, in addition to the above operation, the secondary side injector for supplying fuel in the high rotation and high load operation region is arranged at a position farther from the engine combustion chamber than the primary side injector. Therefore, for example, as compared with the case where the secondary side injector is arranged near the primary side injector (i.e., the case where the secondary side injector is arranged closer to the engine combustion chamber), the secondary side injector to the combustion chamber The length of the passage leading to is increased and the injected fuel is mixed with the intake air for a longer period of time to stay in the intake passage. As a result, the cooling action of the intake air due to the heat of vaporization of the fuel is promoted, and the charging efficiency of the intake air is increased.

[0016]

Therefore, according to the fuel supply device for an engine of each invention of the present application, the following effects can be obtained.

According to the fuel supply system for an engine of the first and second aspects, the delay in the fuel transportation to the engine combustion chamber when the fuel supply from the secondary injector is started is eliminated by increasing the fuel amount. Rather than increasing the intake air flow rate in the secondary intake passage, it is possible to eliminate the shock caused by the delay in fuel transportation during acceleration. It is possible to surely prevent the fluctuation of the fuel consumption, and it is possible to improve the driving feeling and the fuel consumption performance or the output performance at the same time. Further, in particular, according to the engine fuel supply device of the second aspect, the increase of the intake flow velocity in the secondary intake passage is achieved by the control valve arranged on the primary intake passage side, which has a relatively simple structure and is inexpensive. By doing so, it is possible to suppress the cost increase associated with the attachment of the flow velocity increasing means as much as possible.

According to the fuel supply system for an engine of the third aspect, in addition to the above-mentioned effects, the secondary side injector provided in the secondary side intake passage used in the high rotation and high load operation region is sucked as much as possible. Since it is arranged on the upstream side to promote the intake air cooling due to the heat of vaporization of the fuel, the intake charging efficiency is increased and a higher output operation is realized.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel supply system for an engine according to the present invention will be specifically described below with reference to the embodiments shown in the accompanying drawings.
FIG. 1A shows an automotive rotary piston engine 1 including a fuel supply device according to an embodiment of the present invention. This engine 1 accommodates a rotor 13 planetarily rotating around a rotor shaft 14 in a casing 11 having a trochoid inner peripheral surface, and forms three combustion chambers 12, 12, 12 around the rotor 13. Become. An intake port 15 is opened in the combustion chamber 12 corresponding to the intake stroke, and the intake passage 2 is connected to the intake port 15.

The intake passage 2 is divided into an upstream collecting passage 21 located on the upstream side, and a primary intake passage 22 branched at a downstream end of the upstream collecting passage 21 and connected to the intake port 15, respectively. And the secondary side intake passage 23. A primary side throttle valve 3 and a secondary side throttle valve 4 are arranged at the connecting portions between the upstream side collecting passage 21 and the primary side and secondary side intake passages 22 and 23, respectively. Of the primary side throttle valve 3 and the secondary side throttle valve 4, the primary side throttle valve 3 is connected to an accelerator pedal (not shown),
It realizes an opening degree corresponding to the depression amount of the accelerator pedal, and can be operated over the entire load region of the engine. On the other hand, the secondary throttle valve 4
Is mechanically connected to the primary side throttle valve 3 such that the primary side throttle valve 3 opens and closes in conjunction with the opening and closing movement of the primary side throttle valve 3 only in a high load region where the opening degree of the primary side throttle valve 3 is equal to or larger than a predetermined opening degree. (The connection mechanism is not shown).

Further, a primary side injector 5 and a secondary side injector 6 are arranged in the primary side intake passage 22 and the secondary side intake passage 23, respectively. Of these two injectors 5, 6, the primary injector 5 is provided at a position relatively close to the combustion chamber 12, but the secondary injector 6 is the primary injector.
It is arranged at a position farther from the combustion chamber 12 than 5. The operation of the two injectors 5 and 6 is controlled by a control signal from a control unit 10 which will be described later. Specifically, as shown in FIG. Switching line L with a rotation speed RPS or less or an engine load of a predetermined load PWS or less
In the first operation region on the side of lower rotation speed and low load, only the primary side injector-5 operates, and fuel is injected from the primary side injector-5 into the primary side intake passage 22. On the other hand, in the second operating region on the high rotation and high load side of the switching line L, fuel injection is performed from the secondary injector 6 in addition to the primary injector 5. There is.

In order to define the operating region of each injector, a boost sensor 31 for detecting the engine load as an intake negative pressure is provided at a position in the primary intake passage 22 immediately downstream of the primary throttle valve 3. The engine speed sensor 36 is attached to the rotor shaft 14 of the engine 1.
Are provided respectively. The fuel injection amount of each injector 5, 6 is basically map-controlled according to the intake air amount detected by an air flow meter (not shown) and the engine speed. By the way, as described above, when the operation of each of the injectors 5 and 6 is controlled by the switching line L (see FIG. 2) preset based on the engine speed and the engine load, for example, When the engine 1 is accelerated and its operating region shifts from the first operating region to the second operating region side, fuel injection is performed in addition to the primary injector 5 which has continuously injected fuel until then. Fuel injection is also performed from the secondary side injector 6 that has stopped, and the sum of the injection amounts of these two injectors 5 and 6 is
The required injection amount is set according to the operating state of the engine. However, immediately after the fuel injection from the secondary injector 6 is started, there is no residual fuel in the primary intake passage 22, so the injected fuel from the secondary injector 6 is actually the engine. 1 combustion chamber 12
Since there is a slight transport delay before it is introduced into the combustion chamber 12 and a portion of the fuel injected from the secondary injector 6 adheres to the passage wall and is not immediately introduced into the combustion chamber 12, As described above, even if the above is achieved, the air-fuel ratio becomes lean immediately after the transition from the first operating region to the second operating region, resulting in a shock and deterioration of the driving feeling. Is.

Therefore, in this embodiment, by applying the present invention, a control valve 7 for narrowing the passage area of the primary intake passage 22 is provided at a position downstream of the primary throttle valve 3 in the primary intake passage 22. It is arranged. This control valve 7
Corresponds to the flow velocity increasing means according to claim 1, is driven by a pressure-responsive actuator 32, and the opening degree (that is, the throttle amount) is through the negative pressure introducing pipe 35 to the primary side. The degree of dilution of the intake negative pressure with the atmospheric pressure introduced from the downstream side of the throttle valve 3 is adjusted by controlling the solenoid valve 33.

The solenoid valve 33 is operated and controlled on the basis of a control signal from a control unit 10 which will be described later, and as shown in FIGS. The operating region shifts from the first operating region over the switching line L to the second operating region side, and moreover, a predetermined time (FTMPr
The control valve 7 is operated only for yS / V) so as to throttle the primary side intake passage 22.

As shown in the block diagram of FIG. 1B, the control unit 10 reads the operating range from the current operating range operating range map 42 of the engine 1 based on the engine speed (RPS) and the engine load (PWS). Based on the judging means 41 and the current driving area signal output from the driving area judging means 41, the primary injector-5 is provided.
Only, or injector-driving means 43 for outputting a driving signal to both the primary-side injector 5 and the secondary-side injector 6, and a flow velocity increasing means (that is, a control means for receiving a signal from the operating area determining means 41). A flow velocity control signal output means 44 for outputting an operation signal to the valve 7), and a timer 4 for limiting the signal output from the flow velocity control signal output means 44 within a predetermined time (FTMPryS / V) after shifting to the operating region.
And 5 are provided.

As described above, when the control signal from the control unit 10 is used to reduce the passage area of the primary side intake passage 22 for a predetermined time when the operating region is changed during acceleration, the intake air supplied through the upstream collecting passage 21 is drawn. Since the air amount is constant according to the operating state of the engine regardless of the throttling action of the control valve 7, the amount of intake air flowing through the secondary intake passage 23 side is relatively increased and the intake flow velocity is increased. Becomes As a result, when fuel is injected from the secondary injector 6 into the empty secondary intake passage 23 at the time of transition of the operating region, the injected fuel rides on the high-velocity intake flow and quickly flows into the combustion chamber 12. In addition to being transported to the side, because of the high flow velocity, there is little adhesion of injected fuel to the passage wall, and as a synergistic effect of these, a primary lean state of the air-fuel ratio immediately after the transition of the operating region does not occur, Operation with the fuel amount corresponding to the required fuel amount is performed,
It is possible to reliably prevent the occurrence of a shock during acceleration without causing problems such as an increase in fuel consumption and a change in air-fuel ratio as in the conventional case.

Further, in this case, as described above, the secondary side injector 6 is arranged at a position farther from the engine combustion chamber 12 than the primary side injector 5 and the intake port 15 in a mixed state of fuel and intake air. Since the period leading up to is extended, the cooling effect of the intake air by the injected fuel is further promoted, and the intake charging efficiency is improved by that much to ensure high output performance in the high rotation and high load region. It is possible.

Further, since the throttling action of the control side intake valve 22 of the primary side intake passage 22 is limited to a predetermined time after the shift to the operating region, it is almost impossible to impair the drivability of the engine. Absent.

Next, the operation control of the control valve 7 as described above will be briefly described based on the flow chart of FIG. 4. After the control is started, first, in step S1, the current operating region is determined. As a result, when it is determined that the current time is in the first operation region, normal control is performed by fuel injection of only the primary injector 5 (step S7).

On the other hand, if it is determined that the current operating region is the second operating region, it is further determined in step S2 whether or not the previous operating region was also the second operating region, and the previous operating region was the first operating region. In this case, since the first operating region has shifted to the second operating region for the first time, fuel injection from the secondary injector 6 is started (step S3), and at the same time, the control valve 7 is used to suppress the fuel transportation delay. ON operation
(That is, diaphragm operation) (step S3). The ON operation of the control valve 7 is continued for a predetermined time and is turned OFF (that is, the throttle state is released) after the elapse of the predetermined time.
(Steps S5, 6). On the other hand, as a result of the determination in step S2, if the previous operation was also in the second operation range, fuel injection from the secondary injector 6 has already started, and no special control is performed.

[Brief description of drawings]

FIG. 1A is a system diagram of an engine including a fuel supply device according to an embodiment of the present invention.

FIG. 1B is a functional block diagram of the fuel supply device shown in FIG. 1A.

FIG. 2 is an operating region diagram of an engine including the fuel supply system shown in FIG. 1A.

FIG. 3 is an explanatory view of operating conditions of the solenoid valve shown in FIG. 1A.

FIG. 4 is a control flowchart of the fuel supply system shown in FIG. 1A.

FIG. 5 is an operating region diagram of a conventional engine fuel supply device.

[Explanation of symbols]

1 is an engine, 2 is an intake passage, 3 is a primary throttle valve, 4 is a secondary throttle valve, 5 is a primary injector, 6 is a secondary injector, and 7 is a control valve 7.
7, 10 are control units, 21 is an upstream collecting passage, 22 is a primary intake passage, 23 is a secondary intake passage, 3
1 is a boost sensor, 32 is an actuator, 33 is a solenoid valve, 34 and 35 are negative pressure introducing pipes, and 36 is an engine speed sensor.

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location F02M 69/00 360 C 7825-3G G 7825-3G

Claims (3)

[Claims] 1. A low-speed engine or low-load operation of an engine, wherein a primary-side injector and a secondary-side injector are respectively arranged in a primary-side intake passage and a secondary-side intake passage that communicate independently with a combustion chamber of the engine. In the region, the fuel is supplied only by the primary side injector, and in the high rotation and high load operation region, the fuel is simultaneously supplied from both the primary side injector and the secondary side injector. In the case where the operating region of the engine shifts from an operating region in which only the primary side injector operates to a operating region in which both the primary side injector and the secondary side injector operate, the secondary only for a predetermined time. It is characterized in that a flow velocity increasing means for accelerating the intake flow velocity of the secondary side intake passage in which the side injector is arranged is provided. Fuel supply device for the engine. 2. The fuel for an engine according to claim 1, wherein the flow velocity increasing means is constituted by a control valve for reducing a passage area of the primary side intake passage in which the primary side injector is arranged. Supply device. 3. The fuel supply device for an engine according to claim 1, wherein the secondary injector is located farther from the combustion chamber than the primary injector.