JPH02207132A - internal combustion engine - 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] On Ll! 5 plates ±1 The present invention relates to an internal combustion engine that has high output characteristics from a low speed range to a high speed range.

lLJ In order to increase the filling efficiency of the intake air by utilizing the intake inertia and intake pulsation, an intake passage suitable for the low speed range and an intake passage suitable for the high speed range are formed to correspond to the rotational state of the internal combustion engine. Some internal combustion engines were equipped with switching means to direct intake air to either the low-speed intake passage or the high-speed intake passage (
(See Japanese Patent Application Laid-Open No. 120817/1983).

19JuiL1LLHongshingdanThe conventional internal combustion engine described above has the following characteristics:
As shown in FIG. 8, although it has a high output characteristic, near the switching speed, the output characteristic decreases in a trough-like manner.

The present invention relates to an improvement of an internal combustion engine that overcomes these difficulties, and includes variable intake means that switches between different output characteristics according to constant operating conditions, and a plurality of exhaust system communication sections that are predetermined to have different output characteristics. variable exhaust device means that changes and switches according to operating conditions, and a variable exhaust device means that changes and switches a specific engine output characteristic among the output characteristics of each of the exhaust means in a portion where the engine output characteristics decrease that occurs under the operating conditions where the intake means is switched. The present invention is characterized in that the switching operating conditions of the intake means and the exhaust means are made different so that the vicinity of the maximum value coincides with each other.

As described above, the present invention provides variable intake means that changes different output characteristics according to fixed operating conditions, and variable exhaust means that changes and switches a plurality of exhaust communication parts according to predetermined operating conditions so as to have different output characteristics. Because of this, it is possible to maintain high intake and exhaust characteristics over a wide operating range, increasing charging efficiency and obtaining good engine output characteristics.

Further, in the present invention, the intake air is adjusted so that the vicinity of a maximum value of a specific engine output characteristic among the output characteristics of each of the exhaust means corresponds to a decrease in the engine output characteristics that occurs under the operating condition in which the intake means is switched. Since the switching operating conditions for the intake means and the exhaust means are different, a local decrease in the engine output characteristics of one of the intake means and exhaust means is compensated for by a local increase in the engine output characteristic of the other, thereby improving the engine output characteristics. The period of increase and decrease is narrow and the overall level can be maintained at a high level.

An embodiment of the present invention illustrated in FIGS. 1 to 3 will be described below.

The illustrated 4-stroke engine 1 installed in an automobile is an in-line 4-cylinder 4-stroke engine, in which a cylinder head 3 is integrally connected to the upper end of a cylinder block 2, and each cylinder 41 is provided in series with the cylinder block 2. ．．
A piston 5 is slidably fitted into the cylinder 42.4s and 44, and a combustion chamber 6 is defined at the top of the cylinder 4 by the cylinder block 2 and the piston 5.

Also, two pairs of intake boats 7 and two exhaust boats 8 are formed in the cylinder head 3, and each intake boat 7 and exhaust boat 8 have an intake port 9. Each combustion chamber 6 is opened through an exhaust port 10, and each intake port 9 and exhaust port 10 are provided with an intake valve 11. An exhaust valve 12 is provided so as to be openable and closable.

Furthermore, the upstream side of the intake boats 7 is gathered into one, and the upstream end thereof is connected to the intake passage 14 of the intake manifold 13, and the junction between the intake passage 14 and the bypass passage 15 is located directly below the air cleaner 16, and the intake passage 14 and the air cleaner 16 is provided, and the intake passage 14 and the bypass passage 15 are communicated with each other when the engine speed Ne is n1 or less.
Intake passage 1 is designed so that the maximum output torque can be obtained when
4. The sum of the communication lengths of the bypass passages 15 is set, the intake switching valve 17 is switched at N1, the intake passage 14 and the air cleaner 16 are communicated, and the intake passage 14 is set so that the maximum output torque can be obtained when n=. The passage length is set.

Furthermore, the downstream side of the exhaust boat 8 is assembled into one, the downstream end of which is connected to the exhaust passage 19 of the exhaust manifold 18, and each cylinder 4+, 42.4s.

44 respectively connected to exhaust passages 19. , 192
.

19, , 194, 1st. Fourth exhaust passage 19. ,
194 are collected, and the second. Third exhaust passage 19
2° 193 are assembled, and there are first communication ports 201 and 202 on the downstream side of these collection parts, and a second communication port on the upstream side thereof.
Communication port 21. , 212 are formed, and this first communication port 2
0, , 202 and the second communication port 21. , 212, respectively, and a first exhaust switching valve 22. , 222, second exhaust switching valve 23. , 23. is provided, and when the engine speed Ne is lower than n=, the exhaust passage 1
The passage length of exhaust passage 19 is set to a length that can generate high torque in the low speed range, and in an intermediate state between nl and n=
The passage length up to the first communication port 20 in the exhaust passage 19 is set to a length that can generate high torque in the medium speed range, and in a state higher than nl+n2, the passage length in the exhaust passage 19 up to the second communication port 21 is set to be high in the high speed range. Torque is generated and the length is set.

Moreover, the 4-cycle engine 1 is provided with an ECU (not shown), and this ECU receives inputs from the engine speed Ne, throttle opening θth, and intake negative pressure PB, adjusts the fuel injection amount, and controls the 4-cycle engine 1. The operating status of the machine can be controlled.

Then, in the ECU, the engine speed Ne is n+, n
z, (n+ < nz), the first exhaust switching valve 22 is in the closed state. Opening the second exhaust switching valves 23,
When the engine speed Ne is N+ between nI+n2, these first exhaust switching valves 17 are switched so that the intake switching valve 17, which is in communication between the intake passage 14 and the bypass passage 15, is switched into the communication state between the intake passage 14 and the air cleaner 1G. Valve 22. Second exhaust switching valve 23. A control signal is sent to the intake switching valve 17.

Note that the intake switching valve 11. First exhaust switching valve 22. A hydraulic or electromagnetic actuator is attached to the second exhaust switching valve 23 to open and open the valve.

Since the embodiment shown in FIGS. 1 to 3 is configured as described above, when the 4-stroke engine 1 is started and operated in a low speed range such as idle link, the intake passage 14 and the air cleaner The intake switching valve 11 is closed so that communication with the first exhaust switching valve 22.16 is blocked. The second exhaust switching valve 23 is also closed, and both the intake passage length and the exhaust passage length of the 4-stroke engine 1 are long, and as shown in FIG. 4, the 4-cycle engine 1 has output characteristics suitable for low speed ranges. It operates at a relatively high torque.

Next, when the rotation speed of the 4-cycle engine 1 reaches n,
The first exhaust switching valve 22 is opened and the 4-cycle engine 1
The length of the exhaust passage is short enough to generate large torque in the medium speed range, and the exhaust system can obtain torque characteristics suitable for the medium speed range.

Furthermore, when the rotational speed of the 4-cycle engine 1 reaches N1, the intake switching valve 11 is switched and the 4-cycle engine 1
The length of the intake passage is short enough to generate large torque in the high-speed range, and the intake system can obtain torque characteristics suitable for the high-speed range.

Furthermore, when the rotational speed of the 4-cycle engine 1 reaches n2, the second exhaust switching valve 23 is opened, and the exhaust passage length of the 4-stroke engine 1 is further shortened to the extent that large torque can be generated in the high-speed range. The system provides torque characteristics suitable for high-speed range.

In the exhaust system, around the rotation speed nl+n2 where the torque locally decreases due to a change in the passage length, each passage length is set so that the torque of the intake system becomes maximum in that vicinity, so the intake system and exhaust The torque decreasing portions of the system are mutually complemented by the torque maximum portions, resulting in a high torque level with small fluctuations over the entire operating range.

In the above embodiment, the intake passage length is changed in order to change the intake characteristics, but the intake characteristics may also be changed using a so-called opening/closing pulp timing conversion valve train that changes the valve opening/closing timing of the intake and exhaust valves. .

and variable pulp timing conversion valve [1 low.

It is also possible to switch between medium and high speeds in three stages, and to change the passage length of the exhaust system in four stages. In this embodiment, output characteristics as shown in FIG. 5 can be obtained.

In addition, in an engine having six cylinders, the exhaust passages 24 are connected as shown in FIG. 6, and the exhaust passages 24 are communicated with each other by a communication passage 25, and the communication passage 25 is partitioned so as to be openable and closable. Valve 26.21 may be inserted, 120°
Since the exhaust pulsation at intervals can be utilized, the exhaust system can be adjusted extremely effectively.

Furthermore, if the end portion of the exhaust passage 24 is configured as shown in FIG. 7, and an exhaust switching valve 28 is interposed therein, the number of switching stages can be increased.

By increasing the number of exhaust switching valves 26, 27, and 28 in this manner, the number of switching stages can be easily increased.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal sectional front views of main parts of the internal combustion valve according to the present invention, with Figure 1 showing the intake/exhaust switching valve in a low speed state, and Figure 2 showing it in a high speed state. FIG. 3 is a view from the ■-■ arrow direction, FIG. 4 is an output characteristic diagram of the above embodiment, FIG. 5 is an output characteristic diagram of the other embodiment, and FIG.
FIG. 7 and FIG. 7 are schematic diagrams of further embodiments, respectively.
FIG. 8 is an output characteristic diagram of the conventional one. 1... 4-stroke engine, 2... cylinder block, 3... cylinder head, 4... cylinder, 5...
... Piston, 6... Combustion chamber, 7... Intake boat,
8...Exhaust boat, 9...Intake port, 10...Exhaust port, 11...Intake valve, 12...Exhaust valve, 13...
Intake manifold, 14... Intake passage, 15... Bypass passage, 16... Air cleaner, 11... Intake switching valve, 18... Exhaust manifold, 19... Exhaust passage, 20... No. 1 communication port, 21... 2nd communication port,
22...First exhaust switching valve, 23...Second exhaust switching valve. Figure 3 Filling Figure 4 "S1 e n+ N1 nZ NZ n3 e Figure 5 Ne Ne e

Claims (1)

[Claims] The intake means includes: variable intake means for switching different output characteristics according to predetermined operating conditions; and variable exhaust system means for changing and switching a plurality of exhaust system communication parts according to predetermined operating conditions so as to have different output characteristics. Each switching operation of the intake means and the exhaust means is performed so that the vicinity of the maximum value of a specific engine output characteristic among the output characteristics of each of the exhaust means corresponds to the portion where the engine output characteristic decreases that occurs under the operating conditions in which the intake means and exhaust means are switched. An internal combustion engine having variable exhaust means characterized by having different conditions.