Intake manifold for an automobile engine

Abstract

To provide an intake manifold, having an inner space surrounded with a surge tank and branch pipes, which enables a simple structure to prevent noise generation and freezing of moisture included in blow-by gas.SOLUTION: A surge tank 1 is positioned at an end section of an intake manifold and branch pipes 2 to 4 are extended first in a downward direction from the surge tank 1 and then in a longitudinal direction toward a connection flange 5. Thus, the intake manifold has an inner space 11 surrounded with a group of the branch pipes 2 to 4 and the surge tank 1. A PCV port 15 protrudes from the surge tank 1 toward the inner space 11. The inner space 11 is filled with heat and acoustic insulation material 21 so as to enclose the PCV port 15. Therefore, the intake manifold can prevent: noise due to vibration of the branch pipes 2 to 4; and freezing of moisture included in blow-by gas at the PCV port 15.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The invention of the present application relates to an intake manifold for an automotive engine.

Background Art

[0002] A multi-cylinder engine includes an intake manifold, and the intake manifold includes a surge tank and a plurality of branch pipes branched therefrom. And, a throttle body is connected to an intake inlet provided in the surge tank, and intake air whose flow rate is controlled by a throttle valve is distributed to each branch pipe through the surge tank.

[0003] There are various aspects of the intake manifold for an automotive engine. However, in terms of the arrangement relationship between the surge tank and the branch pipes, the branch pipes often bend downward from the surge tank and then turn upward and bend toward the intake side surface of the cylinder head.

[0004] Furthermore, when looking at the relationship between the surge tank and the branch pipes with the cylinder bank direction as the front-rear direction, there are types where the surge tank is in a front-rear longitudinal posture, the branch pipes wind around the surge tank, and the throttle valve is arranged at the front end or the rear end of the surge tank, or types where the surge tank is arranged outside the front-rear direction of the intake side surface of the cylinder head, and the branch pipes bend toward the intake side surface while extending in the front-rear direction.

[0005] On the other hand, problems related to the intake manifold itself or its peripheral parts include problems of noise and freezing of blow-by gas in a cold environment. As one of the noise problems, there is a problem of noise generated from the fuel injector. In this regard, Patent Document 1 discloses covering the exposed part of the fuel injector with a protective member.

[0006] On the other hand, regarding the problem of blow-by gas freezing (more precisely, the freezing of moisture contained in blow-by gas), Patent Document 2 discloses that the PCV passage and the EGR passage are arranged adjacent to each other in the intake manifold, thereby preventing the freezing of moisture contained in blow-by gas by the heat of the EGR gas. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2007-177753 [Patent Document 2] Japanese Patent Publication No. 2013-151906 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Now, in intake manifolds, the intake air can resonate inside the branch pipes, generating noise. In particular, if the branch pipes are made long to aim for an inertial supercharging effect, or if the length of the branch pipes is increased by placing the surge tank at the front or rear end of the intake side, the noise tends to become more pronounced. However, while Patent Document 1 can prevent noise from the fuel injector, it cannot prevent noise generated from the intake manifold.

[0009] On the other hand, regarding the problem of water freezing in blow-by gas, Patent Document 2 has the problem that while it can prevent water freezing during operation, it cannot prevent water freezing between the time the engine is stopped and has cooled down completely, and the next time it is started.

[0010] The present invention was made to improve this current situation. [Means for solving the problem]

[0011] The present invention relates to an intake manifold for an automobile engine. "It has a surge tank located downstream of the throttle valve, and multiple branch pipes branching off from the surge tank, Each of the aforementioned branch pipes extends from the lower surface of the surge tank in the direction of the crank axis, then changes direction upward and curves toward the intake side of the cylinder head. There are Furthermore, because the lengths extending in the direction of the crank axis are different, the outlets of the multiple branch pipes are aligned in the direction of the crank axis. The aforementioned multiple branch pipes extend in the direction of the crankshaft axis with varying distances from the cylinder head, and the area enclosed by the group of branch pipes and the surge tank faces the cylinder head. External It is an open space." This is the basic structure.

[0012] And in the above basic configuration, " Each of the aforementioned branch pipes is such that adjacent branch pipes are connected as a single unit in the range from the portion connected to the surge tank to the portion that changes direction upwards, The aforementioned space is located between the point where each branch pipe is integrally connected and the surge tank, and has a communication section that also opens on the opposite side from the cylinder head, and the aforementioned space, including the communication section, is sealed with a heat-insulating and sound-insulating material. A PCV port communicating with the surge tank is located in the aforementioned space, and the PCV port is covered. The aforementioned It is filled with heat-insulating and sound-insulating material. Furthermore, a PCV hose is connected to the PCV port, and the entire PCV hose is covered with insulation material. It has the following characteristics. A PCV hose is connected to the PCV port, but in the case of engines designed for cold climates, it is preferable to cover the PCV hose with an insulating material such as urethane resin. Note that this insulating and sound-insulating material can also be called a sound-insulating and heat-insulating material. [Effects of the Invention]

[0014] In this type of intake manifold, the branch pipes vibrate very slightly. but The area enclosed by the group of branch pipes and the surge tank, which serves as the excitation source, Towards the cylinder headSince it is an open space, air column resonance occurs. However, in the present invention, by arranging a sound insulation material in the space, the air column resonance of the space open to the outside is suppressed, and the generation of noise caused by resonance can be prevented or significantly suppressed. Therefore, the quietness of the passenger compartment can be improved.

[0015] In addition, the sound insulation material generally has a heat insulation function. Since the PCV port is covered with the sound insulation material, the PCV port is heat-insulated by the sound insulation material, so that the moisture of the blow-by gas inside the PCV port can be prevented from freezing. In this case, since the heat insulation function of the PCV port by the sound insulation material is maintained even when the engine operation is stopped, for example, even when the operation is stopped and started the next day, the freezing of the blow-by gas can be prevented and the reflux function of the blow-by gas can be maintained.

[0016] Also , as a means for preventing freezing at a portion of the PCV pipe excluding the PCV port 、P Cover the CV hose with a heat insulating material Therefore, it has a high antifreeze effect. It is preferable to use a combination of measures such as tilting the PCV hose so that condensed water does not accumulate.

[0017] Now, since the engine room of the automobile is open downward, foreign objects such as small stones, water, and snow may be splashed into the engine room during running. In addition, since the running wind for cooling enters the engine room from the front grille, rain may enter the engine room during rainfall, and snow may enter the engine room during snowfall.

[0018] When the rain or snow that has entered the engine room touches the sound insulation material, even if a heat-insulating sound insulation material is provided, the heat insulation function may be reduced. In addition, a situation where the sound insulation material is damaged by the splashed small stones should be avoided.

[0019] In this regard, The present inventionWhen the following structure is adopted, since the sound insulation material is at least surrounded from below by a group of branch pipes, it is possible to prevent rain, snow, and small stones from hitting the sound insulation material. As a result, it is possible to maintain the heat insulation effect of the sound insulation material, ensure the effect of preventing the freezing of the moisture contained in the blow-by gas, and also prevent damage to the sound insulation material. Furthermore, since the heat-insulating sound insulation material can be suppressed from coming into contact with cold air, it is possible to prevent a decrease in the heat insulation function of the heat-insulating sound insulation material. Thereby, it is possible to ensure the effect of preventing the freezing of the moisture contained in the blow-by gas without providing a new heat insulation material.

Brief Description of the Drawings

[0020] [Figure 1] It is a view showing the intake manifold of the embodiment, as seen from the side of the cylinder head before the sound insulation material is attached. [Figure 2] It is a view showing the state in which the sound insulation material is attached, as seen from the side of the cylinder head. [Figure 3] It is a view showing the state in which the sound insulation material is attached, as seen from the side facing the cylinder head.

Mode for Carrying Out the Invention

[0021] Next, embodiments of the present invention will be described based on the drawings. This embodiment is applied to the intake manifold of a three-cylinder engine for an automobile. The engine is arranged in the engine room with the crank axis in a long posture in the vehicle width direction, with the exhaust side facing forward and the intake side facing backward in the forward direction of the automobile. Therefore, the engine is a transverse front exhaust (Rear intake) type, Therefore, The intake manifold overlaps the intake side surface of the cylinder head from behind facing the forward direction of the automobile.

[0022] In the following, the terms "front / back" and "left / right" are used to specify direction. The front / back direction is the direction of the crank axis, and the left / right direction is the direction perpendicular to the crank axis and cylinder axis. Therefore, the relationship between front / back and left / right is reversed compared to directions based on the orientation of the vehicle. For the left / right direction, the side facing the cylinder head is considered the inside, and the side away from the cylinder head is considered the outside. Outward is the direction of forward movement of the vehicle, and inward is the direction of reverse movement.

[0023] (1) Basic structure of the intake manifold The intake manifold is elongated in the front-to-back direction and has a surge tank 1 located at the rear, three branch pipes 2-4 (first to third) integrally connected to the surge tank 1, and connecting flanges 5 that integrally connect the outlets of each branch pipe 2-4. When it is necessary to distinguish between the branch pipes 2-4, they will be referred to as the first branch pipe 2, the second branch pipe 3, and the third branch pipe 4, in order from front to back.

[0024] The connecting flange 5 has bolt insertion holes 6 for fixing it to the intake side of the cylinder head. Additionally, an outward-facing EGR gas inlet 7 is provided at the rear of the connecting flange 5. The EGR gas inlet is connected to an EGR gas inlet passage provided in the cylinder head.

[0025] The inlets of each branch pipe 2-4 are connected to the underside of the surge tank 1. Each branch pipe 2-4 starts downward from the surge tank 1, then changes direction to be roughly forward, then upward, and then changes direction again to be roughly horizontal before connecting to the connecting flange 5. Therefore, each branch pipe 2-4 has a low-height downward-facing section (inlet section) 2a, 3a, 4a, a long, longitudinally elongated lower section 2b, 3b, 4b, an upward-facing section 2c, 3c, 4c rising from the lower section 2b, 3b, 4b, and an outward-facing section 2d, 3d, 4d that changes direction from the upper end of the upward-facing section 2c, 3c, 4c.

[0026] Therefore, each branch pipe 2-4 is curved in three dimensions. Also, the lower parts 2b, 3b, and 4b are arranged in the left-right direction such that the lower part 2b of the first branch pipe 2 is located on the outermost side and the lower part 4b of the third branch pipe 4 is located on the innermost side. Furthermore, the lower halves of adjacent downward-facing sections 2a-3a, adjacent lower parts 2b-4b, and adjacent upward-facing sections 2c-4c are connected as a single unit.

[0027] And the area enclosed by the connecting flange 5, surge tank 1, and branch pipes 2-4 is Towards the cylinder head Interior space with openings on both sides (Space part) Although it is numbered 11, the branch pipes 2-4 have their downward-facing sections 2a-3a, lower sections 2b-4b, and upward-facing sections 2c, 3c, 4c connected as one unit. Therefore, the internal space 11 is open in the left-right and upward directions, but not in the downward or front-back directions. Consequently, the internal space 11 is a highly enclosed space. Figure 1 shows the portion of the internal space 11 that is open to the inside. (Communication part) It is displayed with a shaded area.

[0028] The intake manifold is composed of an upper member 8, a middle member 9, and a lower member 10 made of synthetic resin that overlap vertically, and these are joined together integrally by vibration welding using high frequency or ultrasonic waves. In each figure, the boundaries of the members are shown with thick lines.

[0029] As can be best understood from Figure 3, the surge tank 1 is composed of an upper member 8 and a middle member 9, and a base 13 with an air intake port 12 opening upward is provided at the upper end of the surge tank 1. As shown in Figure 1, a throttle valve (throttle body) 14 equipped with a motor 14a is fixed to the base 13.

[0030] As shown in Figure 1, a PCV port 15 is provided protruding from the side of the surge tank 1 facing the internal space 11, into which blow-by gas flows. The PCV port 15 is exposed to the internal space 11 and opens inward, and a PCV hose 16 is connected to its tip via a fitting 17. The PCV hose 16 is covered along its entire length with an insulating material 18 such as urethane resin. The PCV hose 16 is connected, for example, to a gas-liquid separation chamber provided on the exhaust side of the cylinder block via a PCV valve (it may also be connected to a gas-liquid separation chamber built into the head cover).

[0031] As shown in Figure 3, a purge gas introduction port 19 is connected to the intake port 12 to return the fuel vaporized in the fuel tank to the surge tank 1, and a negative pressure extraction port 20 for assisting the brake booster is provided protruding inward from the surge tank 1.

[0032] (2) Sound insulation and heat insulation structure As shown by the parallel diagonal lines in Figures 2 and 3, a thermal insulation and soundproofing material 21 is fitted into the internal space 11 to seal it. The thermal insulation and soundproofing material 21 is made of a porous material made of synthetic resin, such as urethane resin. Therefore, by elastically deforming it, it can be fitted into the internal space 11 in a way that prevents it from coming loose.

[0033] Because the three branch tubes 2-4 have different front-to-back lengths and are offset in the left-to-right direction, the internal space 11 has a front-to-back width that gradually decreases from the outside to the inside, and the third branch tube 4 Between and surge tank 1 It is open to the inside. Therefore, the heat-insulating and sound-insulating material 21 is also formed to match the shape of the internal space 11, and is made to adhere tightly to the inner surface of the intake manifold by utilizing elastic deformation.

[0034] The thermal insulation and soundproofing material 21 may be a single block or composed of multiple blocks. The thermal insulation and soundproofing material 21 can also be integrated into the intake manifold by insert molding. In the case of a retrofit method, it can also be fixed to the intake manifold with adhesive. When composed of multiple blocks, the blocks can also be fixed to each other with adhesive. Furthermore, if there is a gap between the inner surface of the intake manifold and the thermal insulation and soundproofing material 21 when the block-type thermal insulation and soundproofing material 21 is installed on the intake manifold, that gap can also be sealed with an injection-type foam sealant.

[0035] The PCV port 15 is covered with a heat-insulating sound-insulating material 21. In this case, a hole or notch for the PCV port 15 to be inserted may be pre-made in the heat-insulating sound-insulating material 21, or the heat-insulating sound-insulating material 21 may be composed of two blocks, with the PCV port 15 sandwiched between the two blocks. In any case, the PCV port 15 is covered with the heat-insulating sound-insulating material 21, leaving space for the insertion of the PCV hose 16. It is preferable to cover the entire PCV hose 16 with a heat-insulating material 18.

[0036] (3) Summary In this embodiment, the surge tank 1 is positioned behind the connecting flange 5 and the branch pipes 2-4 are long, which has the advantage of being able to effectively utilize inertial supercharging to improve filling efficiency, and the internal space 11 is filled with heat insulating and sound insulating material 21. Therefore, The generation of noise due to air column resonance in the space 11 can be prevented or significantly suppressed. This improves the environment in the crew compartment.

[0037] Furthermore, since the PCV port 15 is covered with a heat-insulating and sound-insulating material 21, it is possible to prevent or significantly suppress the condensation and freezing of moisture contained in the blow-by gas after the engine has stopped operating in cold environments. This prevents the PCV port 15 from being blocked by frozen moisture, even when the engine is started the day after it has been stopped, and ensures the function of blow-by gas recirculation. The entire PCV hose 16 is covered with a heat-insulating material 18. Because It is even more suitable for preventing freezing.

[0038] Furthermore, since it is possible to prevent small stones kicked up during operation from entering the internal space 11 from the left or right, it is also possible to prevent damage to the PCV port 15 by kicked-up stones. It is also possible to prevent problems such as rattling noises during operation caused by kicked-up stones getting stuck on the lower parts 2b, 3b, and 4b of the branch pipes 2-4.

[0039] Furthermore, since adjacent branch pipes 2-4 are integrally connected at their lower parts 2b, 3b, and 4b and their upstream and downstream sides, branch pipes 2-4 exhibit a high level of protection against the thermal insulation and soundproofing material 21. As a result, the degree to which cold air comes into contact with the thermal insulation and soundproofing material 21 is reduced, improving the heat retention function of the PCV port 14 and branch pipes 2-4 by the thermal insulation and soundproofing material 21.

[0040] The embodiments of the present invention have been described above, but the present invention can be further concretized in various ways. For example, the present invention is, 3 It can also be applied to the intake manifolds of multi-cylinder engines other than single-cylinder engines. [Industrial applicability]

[0041] The present invention can be implemented in the intake manifold of an automobile engine. Therefore, it is industrially applicable. [Explanation of Symbols]

[0042] 1 Surge Tank 2-4 branch tubes 5 Connection flanges 8-10 Synthetic resin components that make up the intake manifold 11 Interior space 12 Intake port 13. Base on which the throttle valve is fixed. 14 Throttle valve 15 PCV ports 16 PCV hoses 18. Insulation 21. Thermal insulation and soundproofing materials

Claims

[Claim 1] It has a surge tank located downstream of the throttle valve, and multiple branch pipes branching off from the surge tank, Each of the aforementioned branch pipes extends from the lower surface of the surge tank in the direction of the crank axis, then changes direction upward and curves toward the intake side of the cylinder head, and because the lengths extending in the direction of the crank axis are different, the outlets of the multiple branch pipes are aligned in the direction of the crank axis. The plurality of branch pipes extend in the crankshaft direction with varying distances from the cylinder head, and the portion enclosed by the group of branch pipes and the surge tank is an intake manifold that opens outward toward the cylinder head. Each of the aforementioned branch pipes is such that adjacent branch pipes are connected as a single unit in the range from the portion connected to the surge tank to the portion that changes direction upwards, The aforementioned space is located between the point where each branch pipe is integrally connected and the surge tank, and has a communication section that also opens on the opposite side from the cylinder head, and the aforementioned space, including the communication section, is sealed with a heat-insulating and sound-insulating material. The aforementioned space is provided with a PCV port that communicates with the surge tank, and the PCV port is covered and filled with the aforementioned heat-insulating sound-insulating material. Furthermore, a PCV hose is connected to the PCV port, and the entire PCV hose is covered with insulating material. Intake manifold for an automobile engine.

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