Rail for high-pressure direct injection

Abstract

The present invention aims for obtaining a fuel rail for gasoline direct injection which can be used for the direct injection at a high fuel pressure of 50 MPa or more by increasing the thickness at the portion near the branch hole and using the material having high thickness for the metal seal portion while keeping the weight light and keeping the cost low. A fuel rail for gasoline direct injection made of steel and used at a fuel pressure of 50 MPa or more, the fuel rail having: a plurality of block members 2; and a pipe member 1 which connects an interval between the block members, wherein the block members 2 have: a branch hole 3 which communicates with the pipe member 1; and a metal seal portion 6 to which an injector is connected, and the hardness of the block members 2 is higher than the hardness of the pipe member 1.

Claims

1. A fuel rail for gasoline direct injection made of steel and used at a fuel pressure of 50 MPa or more, the fuel rail comprising: a plurality of block members; and a pipe member which connects an interval between the block members, wherein the block members have: a branch hole which communicates with the pipe member; and a metal seal portion to which an injector is connected, and the hardness of the block members is higher than the hardness of the pipe member.

2. The fuel rail for gasoline direct according to claim 1, wherein a reinforcing member is installed in the interval between the block members in an arrangement direction of the pipe member to increase rigidity of the interval between the block members.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view showing the first embodiment of the present invention.

(2) FIG. 2 is a cross-sectional view cut along line A-A in FIG. 1.

(3) FIG. 3 is a perspective view showing the second embodiment.

(4) FIG. 4 is a perspective view showing the third embodiment.

MODES FOR CARRYING OUT THE INVENTION

First Embodiment

(5) The first embodiment of the present invention will be explained below in FIGS. 1 and 2. (1) is a pipe member, and block members (2) formed separately from the pipe member (1) are provided on both ends of the pipe member (1). In addition, a branch hole (3) is provided on the block members (2) as shown in FIG. 2. As shown in FIG. 2, the branch hole (3) has a T-shape formed by a communication passage (4) extending along an arrangement direction of the pipe member (1) to communicate with the pipe member (1) and a branch passage (5) extending in a vertical direction from the center part in a longitudinal direction of the communication passage (4).

(6) As described above, since the branch hole (3) is provided on the block members (2), the thickness of the pipe member (1) at which the pressure resistance is not particularly important can be formed thinner and only the thickness of the portion near the branch hole (3) at which the pressure resistance is required can be formed thicker. In addition, a metal seal portion (6) is projected at the tip end side of the branch passage (5) to connect an injector with the metal seal portion (6).

(7) In addition, since the block members (2) and the pipe member (1) are separately formed, the block members (2) and the pipe member (1) can be made of different materials with each other. Accordingly, it is possible to use the material having high pressure resistance for the block members (2) compared to the hardness of the material used for the pipe member (1) since higher pressure resistance is required for the block members (2).

(8) For example, the material of the block members (2) can be SUS materials such as Duplex, SUS630, EN1.4418, SUS304N2 and steel materials such as S45C, S55C, SCM420, SCM 430, SCM 435, SCM 440. The material of the pipe member (1) can be SUS materials such as SUS304, SUS304L, SUS 316, SUS 316L and steel materials such as STS370, STKM17, STKM 20, STKM 13 which have lower hardness compared to the above exemplified materials of the block members (2).

(9) As described above, since expensive material having high hardness can be used only for the block members (2), the cost can be kept low. In addition, since the material having high hardness is used for the block members (2), even if the fuel pressure is high, breakage of the branch hole (3) can be prevented. Furthermore, since the metal seal portion (6) provided on the block members (2) also has high hardness, the pressure resistance can be increased at the metal seal portion (6). Thus, the deformation of the metal seal portion (6) can be prevented when connected with the injector.

Second Embodiment

(10) Although two block members (2) are connected with the pipe member (1) in the above described first embodiment, it is also possible to connect four block members (11) with a pipe member (12) as shown in the second embodiment. Furthermore, it is also possible to connect 3, 5 or more block members in the different embodiments. Note that the configurations of the block members (11) and the pipe member (12) are same as those described in the first embodiment.

Third Embodiment

(11) In the third embodiment, same as the second embodiment, four block members (21) are connected with a pipe member (22). Furthermore, as shown in FIG. 4, a reinforcing member (23) is installed in an interval between the neighboring block members (21) in the arrangement direction of the pipe member (22). As described above, since the reinforcing member (23) is installed, the rigidity between the block members (21) can be increased. In the third embodiment, same as the second embodiment, the configurations of the block members (21) and the pipe member (22) are same as those described in the first embodiment.

DESCRIPTION OF THE REFERENCE NUMERALS

(12) 1, 12, 22 pipe member

(13) 2, 11, 21 block member

(14) 3 branch hole

(15) 6 metal seal portion

(16) 23 reinforcing member