JP2003083138A - Cylinder injection engine with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure control accuracy of fuel flow rate in a low load region by injecting optimum injection flow rate of fuel in both regions of a high load region including a supercharging region and the low load region seeming to be in an idling state, exerting engine performance to a maximum and uniformly distributing fuel to each cylinder in the low load region. SOLUTION: This engine is characterized by having a supercharger to force- feed intake air of an intake passage to a combustion chamber, having a first injector controlled in operation to directly inject fuel to the combustion chamber and having a second injector controlled in operation to inject fuel to a surge tank in mid-way of the intake passage in the low load region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder injection engine with a supercharger, and more particularly, to an engine that can maximize engine performance and ensure fuel flow control accuracy in a low load range. The present invention relates to a cylinder injection engine with a feeder.

[0002]

2. Description of the Related Art An engine mounted on a vehicle is provided with a supercharger for pumping intake air in an intake passage to a combustion chamber of each cylinder, and an injector whose operation is controlled so as to directly inject fuel into the combustion chamber. There is a cylinder injection engine with a supercharger. The in-cylinder injection engine with a supercharger requires a large amount of fuel in a high load and high rotation range, but a small amount of fuel is required in a low load and low rotation range such as an idling state.

When injection is performed during the intake stroke in a cylinder injection engine with a supercharger, the intake stroke top dead center (TDC).
It is required to inject fuel between the time and the bottom stroke dead center (BDC) of the intake stroke. The completion of fuel injection during the intake stroke can be easily realized by increasing the fuel pressure or increasing the injection rate of the injector.

Such a cylinder injection engine with a supercharger is disclosed in Japanese Patent Laid-Open Nos. 5-99032 and 10-27.
There is one disclosed in Japanese Patent No. 4077.

The one disclosed in Japanese Patent Laid-Open No. 5-99032 is provided with an air control valve in a bypass passage that bypasses an engine-driven mechanical supercharger and communicates with an intake passage,
A fuel injection valve that injects fuel into the combustion chamber is provided to reduce the fuel injection amount as the idling speed increases during idling and increase the opening of the air control valve to set the idling speed to the target speed. In the in-cylinder injection internal combustion engine to be controlled, when the fuel injection amount becomes equal to or less than the minimum injection amount, the opening amount of the air control valve is decreased while maintaining the fuel injection amount at the minimum injection amount.

The one disclosed in Japanese Unexamined Patent Publication No. 10-274077 includes an injector for directly injecting fuel into the combustion chamber, and in a low load region, fuel is injected in the latter stage of the compression stroke,
In a cylinder injection engine with a supercharger that injects fuel during the intake stroke in the high load range, lowers the fuel pressure supplied to the injector and injects it during the intake stroke in the extremely low load operation range such as during idle operation. Is.

[0007]

As described above, in order to complete the fuel injection during the intake stroke of the cylinder injection engine with the supercharger, the fuel pressure is increased and the injection rate of the injector is increased. By doing so, it is possible to easily respond.

However, in order to increase the fuel pressure, it is necessary to reexamine the fuel pump system, delivery pipe, and other fuel system system configurations, and there is the inconvenience that the system configuration must withstand the pressure increase.

Further, when the injection rate of the injector is increased, the fuel flow rate can be secured at the time of large flow rate in the high load high rotation range and the medium load range of the supercharger, but no problem occurs. When the flow rate is low at low load and low rotation range such as idling, the dynamic range of the injector may become insufficient, which may lead to insufficient fuel flow rate due to over dynamic range, making it difficult to maintain the control accuracy of the fuel flow rate in the low load range. There is inconvenience.

For this reason, the party injection engine with supercharger
It is difficult to inject fuel at the optimum injection flow rate in either the high load range including the supercharging range or the low load range such as idling, which makes it impossible to maximize engine performance. There is.

[0011]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a supercharger for pumping the intake air in the intake passage to the combustion chamber, and operates so as to directly inject the fuel into the combustion chamber. It is characterized in that a controlled first injector is provided and a second injector whose operation is controlled to inject fuel into a surge tank in the middle of the intake passage in a low load region is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The in-cylinder injection engine with a supercharger of the present invention is provided with a first injector whose operation is controlled so as to directly inject fuel into a combustion chamber, so that fuel is provided in the middle of the intake passage in a low load region. By providing the second injector whose operation is controlled to inject into the surge tank, the optimum injection flow rate can be obtained in both the high load range including the supercharging range and the low load range such as the idling state. The fuel can be injected, and the fuel can be evenly distributed to each cylinder by injecting the fuel into the surge tank by the second injector in the low load region.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of the present invention. In FIG. 1, 2 is a cylinder injection engine with a supercharger (hereinafter, simply referred to as “engine”). The engine 2 has three cylinders, and each has a combustion chamber 4.

The engine 2 has an air cleaner (not shown), an intake pipe 6, a surge tank 8 and an intake manifold 10 which are sequentially connected as an intake system, and an intake passage 12 which communicates with the combustion chamber 4 of each cylinder is provided. A throttle valve 14 is provided in the intake passage 12 of the pipe 6. Also, the engine 2
As an exhaust system, an exhaust manifold 16, an exhaust pipe 18, and a catalytic converter (not shown) are sequentially connected, and an exhaust passage 20 that communicates with each combustion chamber 4 is provided.

The engine 2 is provided with a supercharger 22 for pumping the intake air in the intake passage 12 to the combustion chamber 4. Supercharger 2
2, the compressor 24 provided in the middle of the intake passage 12 is driven by a turbine 26 provided in the middle of the exhaust passage 20, and the intake air in the intake passage 12 is pressure-fed to each combustion chamber 4.

The engine 2 is provided with a fuel injection device 28 as a fuel supply system. The fuel injection device 28 includes a first injector 30 and a second injector 32. The first injector 30 is provided for each cylinder so as to face the three combustion chambers 4, respectively. The second injector 32 is provided in the surge tank 8 so as to face the intake passage 12.

The three first injectors 30 and the one second injector 32 are connected to the control means 34. The control means 34 includes, for example, an ignition switch 36 of the engine 2, a throttle opening sensor 38 for detecting a throttle opening, an engine speed sensor 40 for detecting an engine speed, as means for detecting an operating state of the engine 2. Boost pressure sensor 42 for detecting boost pressure,
An intake air amount sensor 44 and the like for detecting the intake air amount are connected and provided.

The control means 34 includes these various sensors 36 to 36.
Based on a signal input from 44, the operation control of the first injector 30 is performed so that the fuel is directly injected into the combustion chamber 4, and the fuel is injected into the surge tank 8 in the middle of the intake passage 12 in the low load region. So the second injector 3
2 is controlled. The second injector 32 is
At least in the low load range including the idling state,
The operation is controlled to inject the fuel into the surge tank 8.

In the fuel injection system 28 of this embodiment, as shown in FIG. 3, the injection flow rate characteristic of the first injector 30 is set to the large flow rate side so as to bring out sufficient performance at high load and high rotation speed. The maximum flow rate and the minimum flow rate are set on the smaller flow rate side than the injection flow rate characteristic of the first injector 30 so that the injection flow rate characteristic of the second injector 32 can be stably operated at low load and low rotation.

Further, the fuel injection device 28, as shown in FIG. 2, corresponds to the required injection amount during idling (the injection amount required when the engine 2 is in the idling state).
The minimum guaranteed flow rate of the injection flow rate characteristic of the first injector 30 is set to a value larger than the idle required injection quantity,
The minimum guaranteed flow rate of the injection flow rate characteristic of the second injector 32 is set to a value smaller than the idle required injection quantity.

The operation of the first injector 30 is controlled by the control means 34 so that the fuel of the injection flow rate set on the large flow rate side is directly injected into each combustion chamber 4 in the high load and high rotation speed region. The second injector 32 is controlled so as to inject the fuel of the injection flow rate set to a smaller flow rate side than the injection flow rate of the first injector 30 into the surge tank 8 in the middle of the intake passage 12 in the low load and low rotation range. The operation is controlled by the means 34.

In this way, the fuel injection device 28 sets the injection flow rate to the large flow rate side and directly supplies the fuel of the injection flow rate set to the large flow rate side into each combustion chamber 4 in the high load and high rotation range. The first injector 30 whose operation is controlled to inject, and the maximum flow rate and the minimum flow rate of the injection flow rate of the first injector 30 are set to the low flow rate side and the injection flow rate of the injection flow rate set to the low flow rate side of the first injector 30 is set. And a second injector 32 whose operation is controlled so as to inject fuel into the surge tank 8 in the low load and low rotation range.

Next, the operation will be described.

The engine 2 is provided with a supercharger 22 for pumping the intake air in the intake passage 12 to the combustion chamber 4 and supplying fuel to the combustion chamber 4
A first injector 30 whose operation is controlled to inject directly into the surge tank 8 is provided, and a second injector 32 whose operation is controlled to inject fuel into the surge tank 8 is provided. The first injector 30 and the second injector 32 are provided. A fuel injection device 28 is provided to control the operation of the fuel cell and the fuel cell by the control means 34.

When the control means 34 causes the fuel injection device 28 to start control (100) as shown in FIG. 4, the fuel injection device 28 determines whether or not the ignition switch 36 is ON (102).

When this judgment (102) is NO, this judgment (102) is repeated. This judgment (102) is YE
In the case of S, it is determined whether or not the engine speed NE is less than the start mode determination engine speed NEST (104).

If the determination (104) is YES, the second injector 32 is selected (106), fuel is injected into the surge tank 8, and the process returns to the determination (102). If this determination (104) is NO, the throttle opening TVO
Is below the fully closed determination throttle opening TVOMN and the engine speed NE is below the idle determination rotation speed NEID (108).

If the judgment (108) is YES, the second injector 32 is selected (110) to inject the fuel into the surge tank 8, and the process returns to the judgment (102). If this determination (108) is NO, the first injector 34
Is selected (112) and the process returns to the determination (102).

As a result, in the engine 2, the injection flow rate is set to the low flow rate side when the engine speed is low and the engine is started or when the load is low such as the idling state in which the throttle valve 14 is fully closed. When the injector 32 is selected and the fuel is injected into the surge tank 8 and the throttle valve 14 is opened to increase the engine speed, the first injector 30 whose injection flow rate is set to the large flow rate side is set. Is selected to inject fuel directly into each combustion chamber 4.

As described above, the engine 2 provided with the supercharger 22 is provided with the first injector 32 whose operation is controlled so as to directly inject the fuel into the combustion chamber 4, and the fuel is introduced into the intake passage in the low load region. By providing the second injector 32 whose operation is controlled so as to inject it into the surge tank 8 in the middle of 12, a low load region such as an idling state,
It is possible to inject fuel at an optimum injection flow rate in any of the high load region including the supercharging region, and the second injector 32 in the surge tank 8 in the low load region.
By injecting the fuel with, the fuel can be evenly distributed to each cylinder.

Therefore, the engine 2 can inject the fuel at the optimum injection flow rate in both the high load range including the supercharging range and the low load range such as the idling state to improve the engine performance. It is possible to maximize the performance, and it is possible to evenly distribute the fuel to each cylinder in the low load range, and it is possible to secure the control accuracy of the fuel flow rate in the low load range.

Further, the engine 2 is provided with the second injector 32 whose operation is controlled so as to inject the fuel into the surge tank 8 in a low load region including at least the idling state, so that the engine is started or idling. It is possible to supply a stable fuel even under a low load such as a state.

Further, the engine 2 operates so that the injection flow rate is set to the large flow rate side and the fuel of the injection flow rate set to the large flow rate side is directly injected into the combustion chamber 4 in the high load and high rotation range. First injector 3 controlled
0, the maximum flow rate and the minimum flow rate of the injection flow rate from the first injector 30 are set to the small flow rate side, and the fuel of the injection flow rate set to the small flow rate side is supplied to the intake passage 12 in the low load low rotation range. A fuel injection device 28 including a second injector 32 whose operation is controlled to inject it into the surge tank 8 on the way is provided.

For this reason, the engine 2 is divided into a high load region and a low load region by the two types of injectors 30 and 32 having different injection flow rate characteristics on the large flow rate side and the small flow rate side. By injecting the fuel, it is possible to expand the flow rate range in which the fuel can be injected. Therefore, the engine 2 can cope with the power without increasing the output of the supercharger 22 by increasing the supercharging pressure without changing to an injector having different characteristics.

In the above embodiment, the two types of the first and second injectors 30 and 32, which are set to have different injection flow rate characteristics on the large flow rate side and the small flow rate side, are switched depending on the load range to supply the fuel. Although the injection is performed, two types of first and second injectors 30 and 32 having different injection flow rate characteristics on the large flow rate side and the small flow rate side may be provided for each cylinder.

Further, in the above embodiment, two types of the first and second injectors 30 and 32 are provided, but the injection flow rate is set to the large flow rate side and the operation is controlled so as to inject directly into the combustion chamber. An injector is provided for each cylinder, and in a high load and high speed range, each injector is operated and controlled so that fuel is directly injected into the combustion chambers of all cylinders.
In the low load and low speed range, the injectors are selectively operated and controlled so that direct injection is performed only in the combustion chambers of the cylinders that can generate the required torque and fuel injection is stopped in the combustion chambers of the remaining cylinders. As a result, the injection flow rate can be set to the small flow rate side and the injector whose operation is controlled to inject the fuel into the surge tank can be eliminated.

Alternatively, an injector whose operation flow rate is set to a high flow rate side and whose operation is controlled so as to directly inject into the combustion chamber is provided for each cylinder, and in the high load and high rotation speed range, the fuel is injected into the combustion chambers of all the cylinders. Each injector is controlled so as to directly inject the fuel, and in the low load and low speed range, each injector is designed to generate the required torque in the low load range by thinning out the fuel into the combustion chamber of a specific cylinder or all cylinders. By selectively controlling the operation of
It is possible to eliminate the need for an injector whose injection flow rate is set to the small flow rate side and whose operation is controlled so as to inject fuel into the surge tank.

Further, the injection flow rate is set to the large flow rate side, and the first injector whose operation is controlled so as to directly inject into the combustion chamber 4 and the injection flow rate is set to the low flow rate side and the surge tank is set in the surge tank. A second injector whose operation is controlled to inject is provided, and when the rate of change of the engine speed or the throttle opening is large such as rapid acceleration, the second injector is switched to the first injector early and the acceleration is gentle. When the rate of change of the engine speed or the throttle opening is small, such as, by controlling the operation so that the second injector is switched to the first injector late, the operation of the first and second injectors can be performed according to the operating state. You can switch appropriately.

[0039]

As described above, the in-cylinder injection engine with a supercharger of the present invention has an optimum injection flow rate in both a high load range including a supercharge range and a low load range such as an idling state. Fuel can be injected, and the fuel can be evenly distributed to each cylinder.

Therefore, the in-cylinder injection engine with a supercharger injects the fuel at the optimum injection flow rate in both the high load range including the supercharge range and the low load range such as the idling state. As a result, the engine performance can be maximized, and the fuel can be evenly distributed to the cylinders in the low load range, so that the control accuracy of the fuel flow rate in the low load range can be secured.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a cylinder injection engine with a supercharger showing an embodiment of the present invention.

FIG. 2 is a diagram showing minimum guaranteed flow rates of a first injector and a second injector.

FIG. 3 is a diagram showing injection flow rate characteristics of a first injector and a second injector.

FIG. 4 is a diagram showing a flow chart of injection control of a first injector and a second injector.

[Explanation of symbols]

2 engine (in-cylinder injection engine with supercharger) 4 Combustion chamber 8 surge tank 12 Intake passage 14 Throttle valve 20 exhaust passage 22 Supercharger 28 Fuel injection device 30 First injector 32 Second injector 34 Control means 36 Ignition switch 38 Throttle opening sensor 40 Engine speed sensor 42 Boost pressure sensor 44 Intake air quantity sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 41/04 F02D 41/04 330E 41/08 325 41/08 325 45/00 310 45/00 310J 312 312H F-term (reference) 3G084 BA11 BA13 CA01 CA03 CA04 CA09 DA01 DA04 EA11 EC01 EC03 FA10 FA33 3G092 AA06 AA08 AA18 BB01 BB06 BB11 DE02S DE03S EA10 EA11 FA01 FA06 GA01 GA04 GA05 GA06 GA18 HA06Z HA09 HA11 HA04 HA01Z04 HE01Z 3 LB04 LB05 MA11 MA18 PA11Z PA14Z PE01Z

Claims (3)

[Claims] 1. A supercharger for pressure-feeding intake air in an intake passage to a combustion chamber, a first injector operation-controlled so as to inject fuel directly into the combustion chamber, and the fuel in the low load range to the intake air. An in-cylinder injection engine with a supercharger, comprising a second injector whose operation is controlled to inject into a surge tank in the middle of a passage. 2. The excess injector according to claim 1, wherein the second injector is operation-controlled to inject fuel into a surge tank in the middle of the intake passage in a low load region including at least an idling state. In-cylinder injection engine with a feeder. 3. A supercharger for pumping the intake air of an intake passage to a combustion chamber is provided, and an injection flow rate is set to a large flow rate side, and fuel having an injection flow rate set to this large flow rate side is loaded in a high load and high rotation range. In the first injector, the operation of which is controlled so as to directly inject into the combustion chamber, and the maximum flow rate and the minimum flow rate of the injection flow rate are set to the low flow rate side and are set to the low flow rate side with respect to the first injector. A supercharger provided with a fuel injection device including a second injector whose operation is controlled to inject a fuel having a different injection flow rate into a surge tank in the middle of the intake passage in a low load and low rotation speed region. In-cylinder injection engine.