JPS5825514A - Internal combustion engine with combustion chamber with multiple intake ports - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine of the type having a combustion chamber with a plurality of intake valves.

Conventionally, one of the technologies for improving fuel efficiency was to configure the intake port of the combustion chamber as a helical port to give high swirl to the fresh intake air and combust it. The large intake resistance caused by the helical shape became a problem, lowering the 1st filling efficiency and causing deterioration in output and fuel efficiency.

Therefore, in order to compensate for this drawback, this Heri Calport (first
A method has also been proposed in which a second intake port is provided in addition to the intake port (intake port) to ensure charging efficiency at high speeds and high loads.
If this happens, conversely, the flow velocity of the intake fresh air will be low at medium to low speeds, medium load ranges, or during deceleration, and it will be difficult to generate an effective swirl, leading to deterioration of output and fuel efficiency in this range. - The present invention was made to solve the above-mentioned problems, and it is designed to ensure charging efficiency at high speeds and high loads, while blocking the secondary intake port at medium to low speeds, medium to low load areas, or during deceleration. Improves combustion stability at idle,
The aim is to improve emissions (HC in %) during deceleration and idling, and to improve fuel efficiency.

It is also an object of the present invention to focus on the fact that the usable air-fuel ratio range changes due to the opening/closing control of the secondary intake port, and to utilize the opening/closing signal of the secondary intake port as an air-fuel ratio control signal to improve fuel efficiency and driving performance. It is also possible to use the optimum air-fuel ratio from the viewpoint of performance.

An embodiment of the present invention will be described below with reference to the drawings.

In Figures 1 and 2, 1 is to the cylinder of the engine;
2 is a combustion chamber. A helical primary intake port 3 for generating a high swirl is opened near the ignition plug 4 of the combustion chamber 2, and an exhaust port 5 is opened at the opposite position.

Further, in the vicinity of the primary intake port 3 in the combustion chamber 2, a secondary intake air /, l(eccentricity/-)) 6 that preferably generates a swirl in the same direction as the primary intake port 3 is provided. Each port) 3.6.5 is provided with a primary intake valve 71, a secondary intake valve 8, and an exhaust valve 9 (not shown) which are independently operated by respective cams. The primary intake port 3 is a helical port to obtain a sufficiently high swirl, while the secondary intake port 4 is designed to reduce intake resistance by /J% as much as possible compared to the primary intake /-). The primary intake port 3 is formed to have a small diameter.
7. Is there an offset along the cylinder wall to properly energize the generated swirl? Upstream of the secondary intake port 6, the flow path control valve (auxiliary slot, top valve) 9, which opens in a medium to high load range, is provided. This flow path control knob 4 operates according to the engine load or rotation speed.

In the illustrated embodiment, the valve 9 is opened and closed by a negative pressure actuator 20 according to the engine load (II negative load).
It is connected to the actuating port 25 of the actuator 20 through the t. Actuator 20 is based on diaphragm 27]
It has a negative pressure working chamber 31 that is partitioned off and a chamber 33 that is open to atmospheric pressure, and the opening P25 is connected to and interlocks with the diaphragm 27. The negative pressure working chamber 31 is connected via a conduit 37 to a pump sensing valve 45 provided in the vicinity of the main throttle valve 17 of the intake passage 15.

Note that 35 is a return spring for the diaphragm 27. Intake air from the intake passage 15 is branched and sent to each primary intake port 3 and secondary intake air/-) 6. The engine sensing valve 45 is provided immediately downstream of the opening degree of 0 when the main throttle valve 17 is viewed from the fully closed position, for example, the opening degree corresponding to when the intake negative pressure is -350 mm.

45-911 is for detecting negative intake pressure of, for example, 350 mlHg.

Now, as shown in Fig. 1, if the idle position of the main slot valve 17 is (a), the steady running position t (b), and the fully open acceleration position t (e), position (b) is the Sensing port 45 changes from on (negative pressure sensing) to off (atmospheric pressure)
Or it is the position where it switches from off to on. Therefore, in the illustrated embodiment, the stationary running is performed at position (b) as a boundary at 2
The range t from position (a) to (b) is called the first steady running position, and the range from (b) to (c) is called the second steady running position. 2 steady running position,
That is, it is included between (b) and (c).

Thus, when the main throttle pulp 17 is located on the upstream side of the gas sensing port 45, negative intake pressure acts on the gas sensing port 45, actuating the actuator 20 to activate the sub-throttle.

Close the tor valve 9. On the other hand, when the main throttle valve 17 is located on the downstream side of the brake sensor housing 45, the brake sensor is activated.
Since atmospheric pressure will act on actuator 2,
0 occupies a non-operating position and opens the sub-throttle and tor valve 9. Therefore, the opening/closing control of the auxiliary slot and the torpulp is performed only by the intake negative pressure (ie, the load) K.

The intake passage 15 is provided with an idle switch 41 and a /4 power switch 42 for detecting the idle position (fully closed position) and fully open position of the main throttle valve 17, respectively. Both the idle switch 41 and the power switch 42 are electrical switches that contact the main throttle valve 17 in the fully closed and fully open positions of the main throttle valve 170, for example.
The actuator 20, which may be a switch, closes the sub-throttle valve 9 only when the intake negative pressure is applied, and the secondary throttle valve 9 is closed.
/-) Cutting the intake air from 6 In an engine having the above-mentioned configuration, the intake air is cut off during idling, sudden deceleration, or steady driving.

When the torque is fully closed or at a predetermined opening degree of 0 or less, the flow path control valve 9 is closed as described above. Therefore, the new air-fuel mixture is taken into the combustion chamber 2 only through the primary intake port 3, so that a sufficiently large flow velocity is obtained and a high swirl is generated. As a result, stratified combustion is possible, especially at idle, resulting in high output.

Low fuel consumption can be achieved. That is, in such a state, the ratio can be suddenly made lean in order to improve fuel efficiency. This relationship is shown in the lia diagram. As shown in FIG. 3, when the sub-throttle valve 9 is fully open, sufficient flow velocity and swirl of intake air can be obtained. Jv'F-19 to 21) was found to be usable. Therefore, the present invention focuses on this point and proposes to use a high air-fuel ratio when closing the auxiliary throttle valve. (however,
Since a misfire occurs when the engine is idling, it is necessary to set the stoichiometric air-fuel ratio to, for example, 14.5 to 14.7, as usual. ) Therefore, according to the present invention, the negative pressure signal 3 as shown in FIG.
．． The signal S3 from the idle switch 41 and/or the engine rotational speed signal 8a is input to the combination rotor unit 50 to increase or decrease the fuel according to these signals. A command is given to the L injector 60. Generally, when a three-way catalyst (not shown) is used as an exhaust purification device, the air-fuel ratio of the exhaust gas is detected by the 02 sensor 53, and the sudden ratio (for example, the theoretical sudden ratio) is set by the combination sensor 50. Feedback (closed loop) control is being used as much as possible. Therefore, in the present invention, the feed pressure is canceled and the air-fuel ratio is made lean (or rich) only when necessary.

A negative pressure signal in the negative pressure line 37 is detected by a vacuum switch 51. The pump switch 51 may be a known diaphragm type electrical ON-OFF switch, for example, and may be used to maintain a predetermined negative pressure (for example -
35, Owsk) is activated, and inputs a negative pressure signal 81 to the combination CPU 50. Further, the feed signal Ss from the %02 sensor 53 is also sent to the computer unit 50. Incidentally, during deceleration, the fuel can generally be turned on or off, so it is preferable to distinguish this from the idling period, when the air-fuel ratio must be maintained at the set air-fuel ratio. However, since the main throttle valve 17 is in the fully closed position during both deceleration and idling, it is impossible to distinguish from deceleration using only the idle signal Ss. Therefore, it is preferable to use the engine speed signal S4 from the tachometer 52 or the like (The number of revolutions at idle is much higher than the number of revolutions at idle) - The fuel injector 60 installed in the intake manifold 3 is connected to the CPU 5.
The amount of fuel injected is adjusted according to the signal from 0.

Using the present invention, the air-fuel ratio used when using a three-way catalyst is 1.
An example of the control mode is shown in the following table. In this table, only the signal sensor 0NK9 is described, and therefore the sensors not listed are OFF.

As can be understood from the table above, the major feature is that when the sub-throttle 9 is fully closed, except when idling, the 1 feedback circuit is opened and a lean mixture is used. Also, during full throttle acceleration, the chi-air mixture is used, as in the past.

In addition, at medium-high speeds and medium-high loads, the flow velocity in the primary intake port 3 can be increased.Although a sufficiently high swirl can be obtained, the intake resistance is large, and the amount of air intake by the primary intake port 3 alone is insufficient. However, in this case, the pressure sensing port 45 is opened to the atmosphere, so the negative pressure acting on the actuator 20 is released, and the secondary intake/flow passage control knob 4 opens. The missing amount of moisture is inhaled. In this case, although the flow velocity of the primary intake (-)31m decreases slightly and the swirl weakens, the swirl is energized by the drift along the cylinder wall on the secondary intake/-toro side, and as a result, sufficient swirl is generated. This makes it possible to achieve good stratified combustion similar to that at wide idle. Therefore, medium to high speed,
This means that high output and low fuel consumption can be achieved even under medium to high loads. Note that the primary intake port 3 preferably has a larger cross section than the secondary intake port 6, but this is because a small diameter does not generate enough swirl, and the secondary intake port 6 is added only from the secondary intake port 3. This is to minimize the deterioration of drivability when the joint is in a commonly used area.

In order to gradually open and close the auxiliary throttle valve, a pressure delay means such as a throttle 39 is preferably provided in the middle of the negative pressure line 37.

As is clear from the above explanation, according to the present invention, two
By providing a flow path control valve (auxiliary throttle valve) f in the secondary intake port that closes depending on the engine load, it is possible to ensure sufficient swirl and filling efficiency in medium-high speed and medium-high load regions, while also ensuring sufficient swirl and filling efficiency during idling or deceleration. In addition to ensuring high swirl and improving combustibility, it is also possible to improve fuel efficiency by making the air-fuel ratio leaner as necessary when the sub-throttle and torque valves are fully closed. .

[Brief explanation of drawings]

Fig. 1 is a diagram schematically showing the main parts of a combustion chamber casing of an internal combustion engine showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the line ■-■ of Fig. 1, and Fig. 3 is a diagram showing the present invention. 2... Combustion chamber, 4... Spark plug, 3... Primary intake port, 6... Secondary intake port, 9...・Sub-throttle valve, 17...Main throttle, Torpulp, 20...Actuator, 41...Idle switch, 42...
・Noyawasui,chi,45...Pakitame-musensingport,60...Feelinnoekta. Patent Applicant Toyota Motor Corporation Patent Application Agent Patent Attorney Akira Maeki Patent Attorney Kazuyuki Nishidate Patent Attorney Masayuki Yoshida Patent Attorney Akiyuki Yamaguchi Figure 1 Figure 2

Claims (1)

[Claims] A primary intake port for generating a high swirl in the form of a helical port and a secondary intake port equipped with a secondary throttle valve operated by an actuator responsive to negative intake pressure in an intake passage having a main throttle valve are provided. In an internal combustion engine with a fuel injector having a combustion chamber, the operating negative pressure circuit of the actuator is connected to a vacuum sensing port that senses negative pressure according to the set opening position of the main throttle valve in the intake passage. The throttle valve can be controlled to open and close according to the engine load, and the negative pressure in the negative pressure circuit is sensed by a vacuum switch, and based on the signal, the fuel injector is activated as necessary when the sub-throttle valve is fully closed. An internal combustion engine having a combustion chamber with a plurality of intake ports, characterized in that a lean air-fuel ratio can be achieved by controlling the amount of fuel injected from the engine.