JPH0216057Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a dual intake valve engine equipped with an electronically controlled fuel injection valve that corresponds to two intake valves and has an intake port branched into two ports by an intermediate wall. .

BACKGROUND OF THE INVENTION Conventionally, electronically controlled fuel injection valves for multi-intake valve engines, such as four-valve engines, have generally been of the single-hole type with a pintle. The position where this injection valve is installed is on the extension of the intermediate wall of the intake port, that is, at the center of the intake port. Therefore, the injected fuel adheres to the intermediate wall and is not smoothly sucked into the cylinder. This causes problems such as an increase in emissions due to air-fuel ratio fluctuations between cycles, combustion fluctuations, deterioration of transient response due to fuel adhesion, and even smoldering of the spark plug when the injected fuel directly hits the spark plug.

In order to deal with such problems, a series of proposals have been made by the present applicant, although the application has not yet been published. (Jitsugan No. 58-94951, Jitsugan No. 58-219570, Jitsugan No. 198403, Jitsugan 58th
−198857).

Problems that the invention aims to solve However, the above series of proposals mainly relate to the fuel injection structure of the electronically controlled fuel injection valve and the improvement of the relationship between the injected fuel and the intermediate wall. Overall, there is room for further improvement in engine performance, such as reduction in emissions, reduction in combustion fluctuations, and improvement in transient response, considering the relationship between fuel consumption, EGR, fuel injection timing, etc.

For example, in an electronically controlled fuel injection valve dual intake valve engine equipped with a three-way catalyst system, the high rotation speed side is used more frequently, and the exhaust gas flow rate increases, resulting in a greater thermal load on the oxygen sensor. There is concern about its thermal deterioration. Furthermore, due to manufacturing variations, etc., the gas may not always be applied uniformly to the oxygen sensor. In such a case, there is a problem that the feedback signal from the oxygen sensor varies and the air-fuel ratio may deviate from a predetermined control range, resulting in a decrease in the apparent purification rate of the three-way catalyst and an increase in the emission value.

In addition, to lower the emission value, NOx
Mass EGR is effective for
If this is done, there is a problem that combustion fluctuations in the engine will increase. Furthermore, since it is possible to improve HC and CO by improving the atomization state of the fuel spray, it is desirable to supply a high-quality air-fuel mixture that is more atomized than conventional proposals.

In order to address these problems and desires, the present invention is capable of sufficiently reducing the emission value even if there is some thermal deterioration of the oxygen sensor or uneven gas distribution, and that increases combustion fluctuation even if a large amount of EGR is performed. This double-intake system can supply high-quality fuel spray that further promotes atomization and reduces adhesion to the intermediate wall, reducing HC and CO, and further reducing transient response. The purpose is to provide valve engines.

Means for Solving the Problems In order to achieve this objective, the dual intake valve engine of the present invention has two fuel injection holes that are oriented toward the two intake valves while avoiding the intermediate wall of the intake port. A multi-intake valve engine with an electronically controlled fuel injection valve provided at the center of the intake port,
A throttle valve is provided independently in the intake manifold of each cylinder, and an EGR orifice is provided downstream of the throttle valve. Then, the period during which the fuel spray injected from the electronically controlled fuel injection valve passes through the intake valve seat section is determined from the engine crank angle period when the air flow velocity at the intake valve seat section of each cylinder rises. It is said to last until the time when the peak value has passed.

Function In such a multi-intake valve engine, each cylinder's intake manifold is provided with an independent throttle valve, which improves the distribution of the intake air amount to each cylinder and equalizes the intake speed of each intake manifold. Ru. In addition, since EGR is performed from the EGR orifice installed in each intake manifold, even if a large amount of EGR is performed, EGR to each cylinder is
Gas distribution is even. Therefore, since the intake air and EGR are equalized, cycle-to-cycle fluctuations are suppressed, combustion fluctuations can be suppressed even when a large amount of EGR is performed, and NOx emissions are reduced by the large amount of EGR.

In addition, since the period during which the fuel spray passes through the intake valve seat is the period when the intake velocity is above a certain value, the atomization of the fuel spray is promoted by the intake velocity energy before it is inhaled into the combustion chamber, and the air A high-quality air-fuel mixture is supplied. Therefore, fuel adhesion to the intermediate wall is further reduced, combustion conditions are further improved, combustion fluctuations are suppressed, and high-quality fuel spray reduces HC and CO emissions, further reducing the amount of adhesion to the intermediate wall. This suppresses the increase in fuel amount at low temperatures and improves the transient response of the engine.

Embodiments Hereinafter, preferred embodiments of the multiple intake valve engine of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a system according to an embodiment of the present invention. In the figure, 1 indicates the cylinder head of the engine, 2 indicates the exhaust port, 3a,
3b is an exhaust valve that discharges combustion exhaust gas.
Reference numeral 4 indicates a combustion chamber, and a spark plug 5 is attached approximately to the center of the combustion chamber 4. Reference numerals 6a and 6b indicate intake valves, and reference numeral 7 indicates an intake port, and in this embodiment, the engine is configured as a four-valve dual intake valve engine. 8 is a surge tank, which distributes air to the intake manifold 9 of each cylinder.

The intake port 7 is branched into left and right ports 7a and 7b by an intermediate wall 10, and the branch port 7
a, 7b are connected to intake valves 6a, 6b, respectively. The intake valves 6a and 6b are opened and closed by an intake valve seat portion 11.

An electronically controlled fuel injection valve 12 is provided on an extension of the intermediate wall 10 of the intake port 7 of each cylinder, that is, at the center of the intake port 7. The details of the structure of the electronically controlled fuel injection valve 12 will be described later.
The electronically controlled fuel injection valve 12 has two fuel injection holes 13a, 13b that are oriented toward the two intake valves 6a, 6b while avoiding the intermediate wall 10. As shown in the figure, fuel sprays 14a and 14b are injected in two directions.

A throttle valve 15 is independently provided in the intake manifold 9 of each cylinder.
Each throttle valve 15 is interlocked with a rod 16,
The amount of intake air is controlled at the same time. An ERG orifice 17 for guiding EGR gas into the intake manifold 9 is provided downstream of the throttle valve 15. Orifice 1 for EGR
7 communicates with the communication path 18, and the communication path 18
The EGR control valve 1 communicates with the exhaust port 2 via a communication path 20. The EGR control valve 19 is a known electric control valve, and controls the flow rate of EGR gas according to the load based on commands from the computer 21. The electronically controlled fuel injection valve 12 is connected to a fuel delivery pipe 22 connected to a fuel tank, and transfers the pressure-fed fuel to a computer 21.
The valve opens and injects in response to a command from an injection pulse signal.

In this injection timing control, the timing at which the fuel sprays 14a and 14b from the electronically controlled fuel injection valve 12 pass through the intake valve seat section 11 is the engine crank angle timing at which the air flow velocity at the intake valve seat section of each cylinder rises. It is defined as the period from the time when the air flow velocity at the intake port reaches its maximum value. The time when this maximum value is exceeded is, for example, the crank angle time after the engine crank angle time when the intake port portion 7 reaches the maximum intake speed, for example, up to about 100 degrees of crank angle after intake top dead center.

The structure of the electronically controlled fuel injection valve 12 is shown in FIG. In the figure, 23 is a fuel supply port, which is inserted and connected to the fuel delivery pipe 22 in FIG. Fuel injection holes 13a and 13b provided at the tip
are opened and oriented in two directions with appropriate narrow angles. 24 is an adapter for introducing auxiliary air;
Reference numeral 25 indicates two or more auxiliary air nozzles for promoting fuel atomization, and the positional relationship between the fuel nozzles 13a and 13b and the auxiliary air nozzle 25 is concentric. An adapter 24 is attached so as to be located in the radial direction of the holes 13a and 13b. The auxiliary air introduction hole 26 is connected to the auxiliary air delivery pipe 27 in FIG. . Further, 30 is an auxiliary air flow rate orifice which equalizes the amount of auxiliary air in each cylinder. Note that 31 is an O-ring, and 32 and 33 are sealing materials for sealing the outside air and auxiliary air.

In the dual intake valve engine configured as described above, fuel spraying, intake, and EGR are performed as follows.

First, intake air is taken into each intake port 7 from the surge tank 8 via the intake manifold 9, but since each cylinder is provided with an independent throttle valve 15, the amount of air is distributed almost evenly. . In addition, EGR gas is also supplied to the EGR orifice 17 provided independently in each intake manifold 7.
Since the air is introduced from the air, it is distributed evenly to each cylinder due to the independent effect and the throttling effect of the orifice. Therefore, the amount of intake air and the amount of supplied EGR gas are equalized for each cylinder, so combustion fluctuations are suppressed. The large amount of EGR improves combustion in the combustion chamber 4 and reduces NOx emissions.

Furthermore, since the fuel injection timing from the electronically controlled fuel injection valve 12 is set when the air velocity at the intake valve seat portion 11 and the intake ports 7, 7a, 7b is high, as shown in FIG. The atomized fuel 14a, 14b is further atomized by this intake velocity energy. Fuel spray with accelerated atomization 1
4a and 14b mix well with air to form a high quality mixture. Because atomization is promoted, the intermediate wall 1
The amount of fuel adhering to the combustion chamber 4 is further reduced, and smoldering caused by adhering fuel directly hitting the spark plug 5 and delays in transient response caused by adhering fuel passing through the wall and entering the combustion chamber 4 are prevented. and combustion fluctuations are suppressed. Further, although fuel is more likely to adhere to the vehicle at low temperatures, reducing the amount of adhered fuel also suppresses an increase in the amount of fuel at low temperatures.

Furthermore, in this embodiment, since auxiliary air is injected into the fuel spray to promote atomization, an even better air-fuel mixture can be obtained. In particular, during idle, etc., each cylinder has a throttle valve 15, so intake air needs to be supplied bypassing the throttle valve 15. , fuel atomization is sufficiently promoted.

Effects of the invention Accordingly, when the present invention is used, various effects as described below can be obtained.

First, there are fewer combustion fluctuations, so the car's drivability is smooth.

In addition, high-quality air-fuel mixture can be supplied to each cylinder with as little cycle fluctuation as possible, making it possible to perform large amounts of EGR and reduce NOx emissions.

In addition, since a high-quality air-fuel mixture can be supplied, incomplete combustion is reduced, and HC and CO emissions can be reduced.

In addition, since the amount of fuel adhering to the port wall can be reduced, acceleration fuel increase and asynchronous fuel increase can be significantly reduced, improving fuel efficiency and reducing HC and CO.

Additionally, there is less need to increase the amount of fuel at low temperatures, and plug smoldering can be significantly improved. Furthermore, direct hit of the plug by fuel spray can be avoided, and smoldering can be prevented.

Additionally, the independent throttle valve and reduced fuel adhesion on port walls improve the engine's transient response.

Furthermore, if auxiliary air is used to promote fuel spray, combustion fluctuations can be suppressed and rotational fluctuations can be reduced even during idling.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a schematic configuration of a system of a dual intake valve engine according to an embodiment of the present invention, FIG. 2 is a side view of an electronically controlled fuel injection valve of the device shown in FIG. 1, and FIG. FIG. 3 is a relationship diagram between the engine crank angle, the air flow velocity at the intake valve seat portion, and the air flow velocity at the intake port portion. 1...Cylinder head, 2...Exhaust port, 3
a, 3b... Exhaust valve, 4... Combustion chamber, 5... Spark plug, 6a, 6b... Intake valve, 7, 7a, 7b
...Intake port, 9...Intake manifold,
10... Intermediate wall, 11... Intake valve seat portion, 12
...Electronically controlled fuel injection valve, 13a, 13b...
Fuel nozzle holes, 14a, 14b...Fuel spray, 15...
...throttle valve, 17...orifice for EGR,
21...Computer, 25...Auxiliary air nozzle.

Claims (1)

[Claims for Utility Model Registration] (1) An electronically controlled fuel injection valve equipped with two-way fuel injection holes that are oriented toward the two intake valves, avoiding the intermediate wall that branches the intake port into two ports. In a multi-intake valve engine that is installed at the center of the intake port, a throttle valve is installed in the intake manifold of each cylinder, and
An EGR orifice is provided on the downstream side of the throttle valve, and the air flow velocity at the intake valve seat of each cylinder rises during the period when the fuel spray injected from the electronically controlled fuel injection valve passes through the intake valve seat. A double intake valve engine characterized by setting the engine crank angle timing to the time when the air flow velocity at the intake port has passed its maximum value. (2) The utility model registration claim set forth in claim 1, wherein the electronically controlled fuel injection valve is constituted by an injection valve having two fuel injection holes and two or more auxiliary air injection holes for promoting fuel atomization. Double intake valve engine.