JPS6315582Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an intake system for an automobile engine, and in particular has two intake ports for each cylinder,
The present invention relates to a structure for arranging a negative pressure outlet to a brake booster in an intake device in which an intake air control valve is disposed at one intake port.

[Prior art] Conventionally, two intake ports were provided for each cylinder, and an intake air control valve was attached to one of the intake ports, and the intake air control valve was opened and closed according to the engine speed. A suction device is known (for example, Japanese Patent Application Laid-open No. 105534/1983). In such an intake device, a surge tank is generally provided immediately before each intake port in order to equalize the amount of intake air taken into each intake port.

On the other hand, in place of the conventional carburetor, an electronically controlled fuel injection system (hereinafter referred to as EFI
That's what it means. )It has been known. In this EFI,
Negative pressure in the intake system is detected as one condition for calculating the optimal fuel injection amount. In an engine that has two intake ports in each cylinder as described above, the negative pressure sensor that detects this negative pressure is installed in a surge tank that equalizes the variation in negative pressure between each cylinder so that it does not detect the variation in negative pressure between cylinders. installed on.
Further, the surge tank is usually provided with a negative pressure outlet to the brake booster, and this negative pressure is used to operate the brakes.

[Problems to be solved by the invention] However, when the surge tank is equipped with both a negative pressure sensor and a negative pressure outlet to the brake booster, the negative pressure in the surge tank is reduced when the brake is applied because the capacity of the brake booster is large. This may cause a large fluctuation in the pressure, which may have an adverse effect on the negative pressure sensor installed nearby. And EFI by negative pressure sensor
If fluctuations occur in the negative pressure control system of the engine, the highly accurate fuel supply control by EFI may be impaired.

In order to solve the above-mentioned problems, this invention was developed to take out negative pressure to the brake booster in an intake system that has two intake ports for each cylinder and an intake air control valve in one of the intake ports. The purpose is to eliminate the negative influence of EFI on the negative pressure control system.

[Means for solving the problem] In order to achieve this purpose, in the intake system of the present invention, two intake ports are provided for each cylinder, and an intake air control valve is disposed in one intake port. In an intake system in which all intake ports are connected to a surge tank in which a negative pressure sensor is installed upstream of an intake air control valve, a negative pressure outlet to a brake booster is provided in the intake port.

[Function] In such an intake device, the distance between the negative pressure outlet provided in the intake port and the EFI negative pressure sensor provided in the surge tank is considerably large, and the negative pressure outlet is connected to the surge tank. Since it is installed at the intake port after the passage area has been narrowed down, the negative pressure inside the surge tank does not change significantly even if negative pressure is taken out from the negative pressure outlet, and the negative pressure from the negative pressure outlet does not fluctuate significantly. The influence on the negative pressure sensor due to removal can be kept small. As a result, a predetermined negative pressure from the surge tank is detected by the negative pressure sensor even when the brake is applied, and highly accurate fuel supply control of the EFI based on the detected value is ensured.

[Embodiments] Preferred embodiments of the intake device of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an intake system according to an embodiment of the present invention, in which the present invention is applied to a 4-cylinder, 4-valve engine. In the figure,
1 is a cylinder head, and each cylinder 2 has two intake ports 3, 4 and two exhaust ports 5.
is provided. The intake ports 3 and 4 are formed within the cylinder head 1, an intake air control valve body 6 attached to the cylinder head 1, and an intake manifold 7 connected to the intake air control valve body 6. They merge into each other in the surge tank 8. The intake manifold 7 and surge tank 8 are formed in front, as shown in FIG.

Of the two intake ports 3 and 4 provided for each cylinder, one intake port 3 is provided with an intake air control valve 9 so that the intake port 3 can be opened and closed. The other intake port 4 is not provided with an intake air control valve 9. The intake air control valve 9 is opened and closed by an actuator 10 attached to the center of the intake air control valve body 6. The actuator 10 has two actuators extending left and right from the actuator 10 to which each intake air control valve 9 is attached. The intake air control valve shaft 11 is connected to the intake air control valve shaft 11 via a lever (not shown). The intake ports 3 and 4 communicate with each other downstream of the intake air control valve 9, and an EFI fuel injection nozzle 12 is provided in the communication portion.

Intake port 3 where intake air control valve 9 of intake manifold 7 is installed
One of the intake ports 3 is provided with a negative pressure outlet 14 to the brake booster 13. The negative pressure outlet 14 is located downstream of the surge tank 8 and upstream of the intake air control valve 9. Then, as shown in the longitudinal section in Fig. 3, the negative pressure outlet 1
4 is provided on the upper wall portion 15 of the intake port 3. It is provided on the upper wall portion 15 of the intake port 3. The union 17 is screwed into the screw hole 16 provided in the upper wall 15 of the intake port 3, and the union 1
A hose 18 made of a material such as rubber is connected to the brake booster 13 .

A negative pressure sensor 19 is attached to the surge tank 8. The negative pressure sensor 19 is connected to the EFI computer 20, and a signal from the negative pressure sensor 19 is sent to the computer 20. Note that 21 is a throttle valve provided on the upstream side of the surge tank 8.

In the intake device configured as above,
Intake is from the surge tank 8 to each intake port 3, 4.
is inhaled into each cylinder 2 through the surge tank 8,
The inside of each intake port 3, 4 becomes negative pressure. and,
In the EFI negative pressure control system, the negative pressure in the surge tank 8 is detected by the negative pressure sensor 19, and the averaged negative pressure of each cylinder is detected. Negative pressure for the brake booster 13 is taken out from a negative pressure outlet 14 provided in one intake port 3, and the brake booster 13 and the brake are operated using this negative pressure.

By providing the negative pressure outlet 14 to the brake booster 13 in the intake port 3, both the negative pressure sensor 19 and the negative pressure outlet 14 are connected to the surge tank 8.
Since it is possible to set the distance between the negative pressure outlet 14 and the negative pressure sensor 19 to be larger than when the negative pressure outlet 14 and the negative pressure sensor 19 are provided in the Fluctuations in the negative pressure within the surge tank 8 during removal are reduced. Also,
Intake port 3 for the intake passage of surge tank 8
Since the cross-sectional area of the intake passage will be constricted considerably, even if negative pressure is extracted from the constricted passage 3,
The influence on fluctuations in the negative pressure within the surge tank 8 can be suppressed to a small level. Furthermore, the negative pressure outlet 1 of the intake port 3
The position where the negative pressure sensor 4 is installed is considerably downstream of the position where the negative pressure sensor 19 is installed, and fluctuations are difficult to propagate from the downstream side to the upstream side. The influence on the pressure sensor 19 can be suppressed. Therefore, by providing the negative pressure outlet 14 in the intake port 3, the negative pressure sensor 1 can be removed from the negative pressure outlet 14 when the brake booster 13 is activated.
9 will be greatly suppressed, and any negative effects on EFI due to brake operation will be prevented.

Furthermore, since the intake air control valve 9 is controlled to be fully closed when the engine is running at low or medium speeds and fully opened when the engine is running at high speeds, the negative pressure outlet 14 is located on the upstream side of the intake air control valve 9 as in this embodiment. As a result, when the intake air control valve 9 is fully closed in the low to medium speed range of the engine, the intake air control valve 9 blocks the blowback of fuel from the cylinder 2 and the backfire. Due to this interruption,
Fuel is prevented from entering the negative pressure system of the brake from the negative pressure outlet 14, and thermal effects on the hose 18 and the like in the event of a backup fire are prevented, and accurate operation of the brake booster 13 is maintained. At the same time, damage to the hose 18 and the like is prevented.
Furthermore, by providing the negative pressure outlet 14 in the upper wall portion 15 of the intake port 13, intrusion of fuel from the negative pressure outlet 14 can be more reliably prevented. On the other hand, in the high speed range of the engine, the intake air control valve 9 is fully opened, but since the amount of intake air is large at this time, there is essentially no fuel blowback or backfire.

Note that the negative pressure outlet 1 provided in the intake port 3
4 can provide similar performance no matter which intake port 3 it is provided with.

[Effect of the invention] As explained above, when using the intake system of the invention, the negative pressure outlet of the brake booster is provided in the intake port, and even when the brake is applied, the negative pressure sensor for EFI is installed in the surge tank. Since fluctuations in the negative pressure of the brake booster are suppressed to a small level, it is possible to eliminate the negative influence on the EFI negative pressure control system due to the negative pressure taken out to the brake booster. As a result, highly accurate fuel supply control using EFI can be smoothly performed, and stable operation of the brake booster can be obtained.

In addition, as shown in the embodiment, if the negative pressure outlet is provided on the upstream side of the intake air control valve of the intake port where the intake air control valve is installed, the blowback of fuel from the cylinder and the backfire can be prevented. It can also be shut off by an air control valve to prevent fuel from entering the brake negative pressure system from the negative pressure outlet and deterioration of hoses and the like.

[Brief explanation of the drawing]

Fig. 1 is a bottom view of the cylinder head and surrounding area of an engine incorporating an intake system according to an embodiment of the present invention, Fig. 2 is a perspective view of the intake manifold and surroundings of the device shown in Fig. 1, and Fig. 3 is a view of the area surrounding the intake manifold. FIG. 3 is a vertical cross-sectional view of the area around the negative pressure outlet of the device. 1... Cylinder head, 2... Cylinder, 3, 4...
...Intake port, 6...Intake air control valve body, 7...Intake manifold,
8... Surge tank, 9... Intake air control valve, 10... Actuator, 13
...Brake booster, 14...Negative pressure outlet, 1
5...Top wall of intake port, 18...Hose, 1
9... Negative pressure sensor, 20... EFI computer.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Two intake ports are provided for each cylinder, an intake air control valve is provided on one of the intake ports, and all intake ports are provided with negative pressure on the upstream side of the intake air control valve. In the intake system connected to the surge tank where the sensor is installed, connect the negative pressure outlet to the brake booster.
An intake device characterized by being provided at an intake port. (2) The negative pressure outlet to the brake booster is provided at the intake port where the intake air control valve is disposed and at a position upstream of the intake air control valve. The intake device according to item 1. (3) The intake device according to claim 1 or 2, wherein a negative pressure outlet to the brake booster is provided on the upper wall of the intake port.