JP-2026075872-A - antifreeze device

Abstract

[Problem] To provide an antifreeze device that prevents water vapor from freezing by raising the temperature of blow-by gas. [Solution] The antifreeze device comprises a PCV passage that recirculates blow-by gas, mainly composed of unburned gas leaked into the engine, to the intake port, and a hot water pipe that circulates hot water, forming a double-pipe structure that covers at least a part of the outer circumference of the PCV passage. The cylindrical part of the PCV passage covered by the hot water pipe is formed in a bellows shape, and the hot water pipe has an inlet for introducing hot water and an outlet for discharging hot water. Both the inlet and outlet are provided on the side wall of the hot water pipe facing upwards towards the vehicle, and the opening of the inlet is provided above the bellows-shaped protrusion. [Selection Diagram] Figure 2

Inventors

• 薦田 拳
• 矢野 正明
• 石山 昂志
• 長山 司

Assignees

• トヨタ自動車株式会社

Dates

Publication Date

20260511

Application Date

20241023

Claims (1)

1. A PCV passage that recirculates blow-by gas, mainly composed of unburned gases that have leaked into the engine, back to the intake port, The PCV passage is provided with a hot water pipe for circulating hot water, which covers at least a portion of the outer perimeter and forms a double-pipe structure. The cylindrical tube of the PCV passage covered by the hot water pipe is formed in a bellows shape. The hot water pipe has an inlet for introducing the hot water and an outlet for discharging the hot water, The inlet and outlet are both provided on the side wall of the hot water pipe facing upwards on the vehicle. The opening of the inlet is an anti-freezing device provided above the bellows-shaped protrusion.

Description

This invention relates to an antifreeze device that prevents water vapor contained in blow-by gas from freezing. To prevent unburned gases from escaping into the atmosphere, engines are equipped with a blow-by gas recirculation system. This system recirculates blow-by gases into the combustion chamber for re-combustion via a PCV (Pneumatic Cylinder Valve) passage connecting the engine's intake side and the cylinder head cover. Blow-by gases contain water vapor, and when a vehicle operates in extremely low-temperature environments, this water vapor cools in the PCV passage and freezes near the junction with the intake manifold. To address this problem, a technique for warming the PCV passage with hot water is known (see, for example, Patent Document 1). Japanese Patent Publication No. 2008-215191 This is a simplified overall view of the antifreeze device according to this embodiment.This is a partial cross-sectional view of the main part of the antifreeze device, showing the flow direction of blow-by gas.This is a cross-sectional view taken along line A-A in Figure 2.This is a magnified view of section B in Figure 2. The present invention will be described below through embodiments, but the claims are not limited to these embodiments. Furthermore, not all configurations described in the embodiments are necessarily essential for solving the problem. Figure 1 is a simplified overall view of the anti-freezing device 100 according to this embodiment. The anti-freezing device 100 mainly consists of the anti-freezing device 100, a PCV passage pipe 110, a hot water pipe 120, and a fixing plate 130. The PCV passage pipe 110 is a metal pipe that forms part of the PCV passage, which recirculates blow-by gas, mainly composed of unburned gases leaked into the engine, to the intake port. One end of the PCV passage pipe 110 is connected to, for example, the crankcase via a connecting hose, and the other end is connected to, for example, the intake manifold via a connecting hose. The hot water pipe 120 is a metal pipe for circulating hot water and is arranged to form a double-pipe structure by covering a portion of the outer circumference of the PCV passage pipe 110. Specifically, as will be described later, the PCV passage pipe 110 is inserted into the interior of the hot water pipe 120. Both ends of the hot water pipe 120 are sealed by being attached to the outer circumference of the PCV passage pipe 110. Two branch pipes are connected to the side wall of the hot water pipe 120: a hot water inlet pipe 121 for introducing hot water into the hot water pipe 120, and a hot water outlet pipe 122 for discharging hot water from the hot water pipe 120. The hot water circulating in the hot water pipe 120 is the coolant used to cool the engine, which has been heated to a high temperature by the engine's waste heat, and circulates, for example, between the engine and the water jacket of the cylinder head. The fixing plate 130 is a fixing member for securing the anti-freezing device 100 to another structure. The anti-freezing device 100 is attached, for example, to the side wall of an engine via the fixing plate 130. Figure 2 is a partial cross-sectional view of the main part of the antifreeze device 100, showing the flow direction of the blow-by gas. As described above, the PCV passage pipe 110 is arranged to penetrate the inside of the hot water pipe 120, and the blow-by gas flows from one end of the PCV passage pipe 110 to the other, as indicated by the black arrows. The portion of the PCV passage pipe 110 covered by the hot water pipe 120 is configured as a bellows-shaped bellows pipe 111. Having a bellows pipe 111 in contact with the hot water increases the area for heat exchange between the cooled blow-by gas and the hot water, allowing for more efficient heating of the blow-by gas even if the length of the hot water pipe 120 covering the PCV passage pipe 110 is short. Furthermore, as described above, a hot water inlet pipe 121 and a hot water outlet pipe 122 are connected to the hot water pipe 120. Specifically, as shown in the figure, the hot water inlet pipe 121 is connected to the hot water pipe 120 so as to communicate with the hot water inlet 120a, which is an opening provided in the side wall of the hot water pipe 120, and the hot water outlet pipe 122 is connected to the hot water pipe 120 so as to communicate with the hot water outlet 120b, which is also an opening provided in the side wall of the hot water pipe 120. As indicated by the white arrows, hot water is introduced into the hot water pipe 120 from the hot water inlet pipe 121 through the hot water inlet 120a, and discharged from the hot water pipe 120 through the hot water outlet 120b to the hot water outlet pipe 122. The hot water inlet 120a and the hot water outlet 120b are arranged in a line along the blow-by gas flow direction on the side wall of the hot water pipe 120. This arrangement allows the hot water introduced from the inlet 120a to create turbule