JP2009074393A - Engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine in which the mal-function of an EGR valve is prevented from occurring. <P>SOLUTION: In this engine, the inside of an intake passage 3 is supercharged by a supercharger 30 driven with an exhaust gas energy, a pneumatic valve actuator 8 is used to drive the EGR valve 9, and the intake passage 3 communicated with the valve operation pressure chamber 34 of the valve actuator 8 through a supercharging pressure transmission passage 20 so that when the supercharged pressure in the intake passage 3 is increased, the valve operation pressure in the valve operation pressure chamber 34 of the valve actuator 8 is increased. When the valve operation pressure in the valve operation pressure chamber 34 is less than a predetermined value, the closed state of the EGR valve 9 is maintained by a valve closing biasing means 9b. When the valve operation pressure in the valve operation pressure chamber 34 is equal to or more than the predetermined value, the EGR valve 9 is opened by the valve operation pressure in the valve operation pressure chamber 34. The passage inlet 20a of the supercharging pressure transmission passage 20 is formed on the intake upstream side more than an EGR gas inlet part 5a to the inlet passage 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine, and more particularly to an engine that can prevent malfunction of an EGR valve.

  As in the present invention, as in the present invention, a turbocharger driven by exhaust energy is used to supercharge the intake passage, and a pneumatic valve actuator is used to drive the EGR valve. An intake passage is communicated with the chamber via a supercharging pressure transmission passage so that the valve operating pressure of the valve operating pressure chamber of the valve actuator increases as the supercharging pressure in the intake passage increases. When the valve operating pressure is less than the predetermined value, the valve closing urging means maintains the closed state of the EGR valve, and when the valve operating pressure in the valve operating pressure chamber exceeds the predetermined value, the valve operating pressure is maintained. There is one in which the EGR valve is opened by the valve operating pressure of the chamber (see, for example, Patent Documents 1 and 2).

In this type of engine, when the fuel increases due to an increase in load, the exhaust energy increases, and when the supercharging pressure increases, the valve operating pressure increases, the EGR valve opens, EGR gas is supplied to the intake passage, maximum combustion temperature is lowered, generation of the NO _X is suppressed. Further, when the fuel energy is reduced due to the load reduction and the exhaust energy is reduced and the supercharging pressure is reduced, the valve operating pressure is lowered, the EGR valve is closed, and the supply of EGR gas is stopped.
However, this conventional engine has a problem because the inlet of the supercharging pressure transmission passage is provided on the intake downstream side of the valve opening of the EGR valve.

JP 2007-85180 A (see FIGS. 1 to 3)

Japanese Patent Laying-Open No. 2007-177698 (see FIG. 1)

The above prior art has the following problems.
<< Problem >> The EGR valve may malfunction.
Since the passage inlet of the supercharging pressure transmission passage is provided on the intake downstream side from the valve opening of the EGR valve, EGR gas enters the valve operating pressure chamber, and the diaphragm and the like in the valve operating pressure chamber are damaged by EGR gas, There is a risk that the EGR valve will malfunction.

<Problem> Engine hunting tends to occur.
Engine hunting is likely to occur. This is because the passage inlet of the supercharging pressure transmission passage is provided on the intake downstream side of the valve opening of the EGR valve, so that the gas pressure of the EGR gas becomes a disturbance and the valve operating pressure of the valve operating pressure chamber is disturbed. This is presumed to be due to this.

  An object of the present invention is to provide an engine that can solve the above-described problems, that is, an engine that can prevent malfunction of an EGR valve.

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 1, a supercharger (30) driven by exhaust energy supercharges the intake passage (3), and a pneumatic valve actuator (8) is used to drive the EGR valve (9). And the intake passage (3) is connected to the valve operating pressure chamber (34) of the valve actuator (8) via the supercharging pressure transmission passage (20), and the supercharging pressure in the intake passage (3) is reduced. The valve operating pressure of the valve operating pressure chamber (34) of the valve actuator (8) is increased as the valve operating pressure is increased. When the valve operating pressure of the valve operating pressure chamber (34) becomes less than a predetermined value, the valve is closed. When the EGR valve (9) is kept closed by the biasing means (9b) and the valve operating pressure in the valve operating pressure chamber (34) exceeds a predetermined value, the valve operation of the valve operating pressure chamber (34) is performed. In an engine in which the EGR valve (9) is opened by pressure,
An engine characterized in that a passage inlet (20a) of a supercharging pressure transmission passage (20) is provided upstream of an EGR gas inlet (5a) to an intake passage (3).

(Invention according to Claim 1)
<Effect> It is possible to prevent malfunction of the EGR valve.
As illustrated in FIG. 1, the passage inlet (20a) of the supercharging pressure transmission passage (20) is provided on the intake upstream side of the EGR gas inlet (5a) to the intake passage (3). It is difficult to enter the valve operating pressure chamber (34), and there is no problem that the diaphragm (8a) or the like of the valve operating pressure chamber (34) is damaged by EGR gas, and the malfunction of the EGR valve (9) can be prevented.

<Effect> Hunting of engine rotation hardly occurs.
Hunting of engine rotation is unlikely to occur. This is because the gas inlet pressure (35a) of the supercharging pressure transmission passage (35) is provided upstream of the EGR gas inlet (5a) to the intake passage (3), so that the gas pressure of the EGR gas is disturbed. This is presumed to be because there is no problem that the valve operating pressure in the valve operating pressure chamber (34) is disturbed.

(Invention according to Claim 2)
In addition to the effect of the invention according to claim 1, the following effect is achieved.
<Effect> Increases engine startability.
As illustrated in FIG. 2, at the time of cold start when the engine temperature is lower than a predetermined value, the supercharging pressure shut-off valve (36) is closed regardless of the supercharging pressure in the intake passage (3). Since the urging means (9b) maintains the closed state of the EGR valve (9), the EGR gas is not supplied to the intake air during the cold start, and the engine startability is improved.

(Invention according to claim 3)
In addition to the effect of the invention according to claim 2, the following effect is achieved.
<Effect> The supercharging pressure transmission passage can be shortened.
As illustrated in FIG. 4, a valve actuator (8) and a supercharging pressure cutoff valve case (36c) are attached to the EGR valve case (7), and a valve cooling water channel (31) is provided in the EGR valve case (7). Since the heat input part (37) of the supercharging pressure cutoff valve case (36c) is exposed to the valve cooling water passage (31), the supercharging pressure between the valve actuator (8) and the supercharging pressure cutoff valve case (36c) is exceeded. The supply pressure transmission passage (20) can be shortened.

(Invention of Claim 4)
In addition to the effect of the invention according to claim 3, the following effect is achieved.
<Effect> Formation of the valve cooling water channel becomes easy.
As illustrated in FIG. 2B, a part of the valve cooling water channel (31) is constituted by the through hole (55) provided in the EGR valve case (7), so that the valve cooling water channel (31) can be easily formed. become.

<Effect> No special sealing plug is required.
As illustrated in FIG. 2B, by inserting the heat input portion (37) of the supercharging pressure cutoff valve case (36a) into one end portion (55a) of the through hole (55), the through hole ( Since the one end portion (55a) of 55) is sealed, a dedicated sealing plug becomes unnecessary.

(Invention according to claim 5)
In addition to the effect of the invention according to claim 4, the following effect is achieved.
<Effect> It is possible to prevent malfunction of the EGR valve.
As illustrated in FIG. 2 (B), the heat input portion (37) of the supercharging pressure shut-off valve case (36c) is fitted into one end portion (55a) of the outlet water passage (58) on the intermediate water passage (57) side. As a result, the cooling water flow does not collide with the heat input portion (37) of the supercharging pressure cutoff valve case (36c), and chattering of the supercharging pressure cutoff valve (36) is prevented. For this reason, the malfunction of the EGR valve (9) can be prevented.

(Invention of Claim 6)
In addition to the effects of the invention according to any one of claims 1 to 5, the following effects are provided.
<Effect> The cooling efficiency of the oil cooler, the EGR cooler, and the EGR valve 3 can be kept high.
As illustrated in FIG. 1, since the water jacket of the oil cooler (49), the water jacket of the EGR cooler (6), and the valve cooling water channel (31) are connected in series, unlike the case where they are connected in parallel, The flow rate of the cooling water is not limited by the restriction of the passage cross-sectional area at the diversion part or the merging part, and the oil cooler (49), the EGR cooler (6), and the EGR valve (9) maintain high cooling efficiency of the three members. be able to.

(Invention of Claim 7)
In addition to the invention of claim 6, the following effect is achieved.
<Effect> The coolant relay pipe can be shortened.
As illustrated in FIG. 1, since the EGR cooler (6) and the EGR valve case (7) are disposed adjacent to each other, the coolant relay pipe (32) connecting them can be shortened.

(Invention of Claim 8)
In addition to the effect of the invention according to claim 6 or 7, the following effect is produced.
<Effect> Cooling performance of engine oil is high.
As illustrated in FIG. 1, since the coolant passes through the oil cooler (49) before the EGR cooler (6), the temperature of the coolant passing through the oil cooler (49) can be lowered, and the engine oil High cooling performance.

<Effect> The durability of the EGR valve can be increased.
As illustrated in FIG. 1, since the cooling water passes through the valve cooling water channel (31) after the EGR cooler (6), the temperature of the cooling water passing through the valve cooling water channel (31) can be increased to some extent, and EGR It is possible to suppress damage due to overcooling of the EGR valve (9), which becomes high temperature in contact with the gas, and to improve the durability of the EGR valve (9).

(Invention according to claim 9)
In addition to the effects of the invention according to any one of claims 6 to 8, the following effects are provided.
<Effect> Cooling efficiency of EGR gas and EGR valve is high.
As illustrated in FIG. 3, since the EGR cooler (6) and the EGR valve case (7) are arranged along the wall of the intake passage (3), the heat of the EGR cooler (6) and the EGR valve case (7) The heat is smoothly radiated to the wall of the intake passage (3), and these overheatings are suppressed. For this reason, the cooling efficiency of the EGR gas and the EGR valve (9) is high.

  Embodiments of the present invention will be described with reference to the drawings. 1 to 8 are diagrams for explaining a diesel engine according to an embodiment of the present invention. In this embodiment, a vertical water-cooled multi-cylinder diesel engine will be described.

The outline of the embodiment of the present invention is as follows.
As shown in FIG. 5, the cylinder head (2) is assembled to the upper part of the cylinder block (26), the oil pan (27) is assembled to the lower part of the cylinder block (26), and the water pump is attached to the front part of the cylinder block (26). (39) and the gear case (28) are assembled, and a flywheel housing (29) is assembled to the rear part of the cylinder block (26).

The configuration of the EGR device is as follows.
As shown in FIG. 1, the exhaust passage (4) communicates with the intake passage (3) through an EGR cooler (6), an EGR valve case (7), and a check valve case (10). The exhaust passage (4) is an exhaust manifold, and the intake passage (3) is an intake manifold.

The configuration of the cooling device is as follows.
As shown in FIG. 1, an oil cooler (49), an EGR cooler (6), and an EGR valve case (7) are provided, a valve cooling water passage (31) is formed in the EGR valve case (7), and an oil cooler (49 ), A water jacket of the EGR cooler (6), and a valve cooling water channel (31) are connected in series.

As shown in FIG. 1, when the water jacket of the EGR cooler (6) and the valve cooling water channel (31) are connected in series by the cooling water relay pipe (32), the EGR cooler (6) and the EGR valve case (7) Are arranged adjacent to each other.
The cooling water is allowed to pass through the water jacket of the oil cooler (49), the water jacket of the EGR cooler (6), and the valve cooling water channel (31) in this order.

The circulation of the cooling water in the cooling device is as follows.
As shown in FIG. 1, the cooling water in the cylinder jacket (59) is divided into a water jacket for the oil cooler (49), a water jacket for the EGR cooler (6), a valve cooling water channel (31), and a cylinder jacket (59). It passes through the suction water channel (60) and the water pump (39) in this order, and returns to the cylinder jacket (59). As shown in FIG. 5, the water jacket of the oil cooler (59) is communicated with the cylinder jacket outlet (41) of the cylinder jacket (59) via the cooling water outlet pipe (42), and the first cooling water relay is connected thereto. The water jacket of the EGR cooler (6) is communicated with the pipe (43), the second cooling water relay pipe (32) is communicated with the valve cooling water channel (31), and this is connected to the cooling water inlet pipe (40 ) Is communicated with the cylinder jacket inlet (40a) of the cylinder jacket (59), and is communicated with the water pump (39) via the suction water channel (60).

The configuration of the EGR device is as follows.
As shown in FIG. 1, a supercharger (30) driven by exhaust energy supercharges the intake passage (3), and a pneumatic valve actuator (8) is used to drive the EGR valve (9). The intake passage (3) is communicated with the valve operating pressure chamber (34) of the valve actuator (8) via the supercharging pressure transmission passage (20), and the supercharging pressure in the intake passage (3) is high. As the valve operating pressure is increased, the valve operating pressure of the valve operating pressure chamber (34) of the valve actuator (8) is increased, and when the valve operating pressure of the valve operating pressure chamber (34) becomes less than a predetermined value, the valve closing bias is applied. When the means (9b) maintains the closed state of the EGR valve (9) and the valve operating pressure in the valve operating pressure chamber (34) exceeds a predetermined value, the valve operating pressure in the valve operating pressure chamber (34) Thus, the EGR valve (9) is opened. The passage inlet (20a) of the supercharging pressure transmission passage (20) is provided on the intake upstream side of the EGR gas inlet (5a) to the intake passage (3). In FIG. 1, reference numeral (45) is an air cleaner, (46) is a combustion chamber, and (47) is an exhaust muffler.

The ideas for improving the cold startability are as follows.
As shown in FIG. 1, a supercharging pressure shut-off valve (36) that is temperature-sensitive and operable is provided in the supercharging pressure transmission passage (20), and during cold start when the engine temperature is less than a predetermined value, Regardless of the supercharging pressure, the supercharging pressure shut-off valve (36) is closed and the EGR valve (9) is kept closed by the valve closing urging means (9b), so that the engine temperature exceeds a predetermined value. During warm start of the engine and during normal operation, the EGR valve (9) is opened and closed in accordance with the supercharging pressure in the intake passage (3) by opening the supercharging pressure cutoff valve (36). As shown in FIG. 2 (A), the intake pressure shut-off valve (36) is provided with bimetal temperature-sensitive deformation means (36a) inside the intake pressure shut-off valve case (36c), and the valve is deformed by its temperature. The valve opening pressure of the body (36b) is changed.

  2A and 2B, a valve actuator (8) and a supercharging pressure cutoff valve case (36c) are attached to the EGR valve case (7), and a valve cooling water channel ( 31), and the heat input portion (37) of the supercharging pressure cutoff valve case (36c) faces the valve cooling water passage (31).

The idea of the valve cooling water channel is as follows.
As shown in FIG. 2 (B), a part of the valve cooling water channel (31) is constituted by a through hole (55) provided in the EGR valve case (7), and one end (55a) of the through hole (55). The heat input part (37) of the supercharging pressure cutoff valve case (36c) is fitted into the end part (55a) of the through hole (55) to be sealed.

  As shown in FIG. 2 (B), the valve cooling water channel (31) is formed into a U-shape with straight inlet side water channel (56), intermediate water channel (57) and outlet side water channel (58). An outlet side water channel (58) is formed by the through hole (55), and heat input to the supercharging pressure cutoff valve case (36c) is provided at one end (55a) of the outlet side water channel (58) on the intermediate water channel (57) side. The part (37) is fitted inside. The inlet side water channel (56) is formed with a dead end on the back side of the intermediate water channel (57), and then a drill hole is made in the rear wall, and an air vent pipe (61) is fitted therein. A pipe is connected to the air vent pipe (61) and connected to the cylinder jacket. The intermediate water channel (57) is formed with a hole having a dead end on the outlet side water channel (58) side, and the inlet side water channel (56) side is sealed with a plug (62).

The arrangement of each component is as follows.
As shown in FIG. 3, the EGR cooler (6) and the EGR valve case (7) are arranged along the wall of the intake passage (3).
As shown in FIGS. 3 and 4, the horizontal direction of the cylinder head (2) is defined with the installation direction of the crankshaft (1) as the front-rear direction and the width direction of the cylinder head (2) perpendicular to the front-rear direction as the horizontal direction When the passage wall of the intake passage (3) is attached and the passage wall of the exhaust passage (4) is attached to the other lateral side of the cylinder head (2), an intake inlet pipe ( 5) is erected, the EGR cooler (6) is installed in the front-rear direction above the passage wall of the intake passage (3), and the intake inlet pipe (5) and the EGR cooler (6) are arranged side by side. Yes. The EGR cooler (6) is located directly above the passage wall of the intake passage (3), that is, when viewed in a direction parallel to the cylinder center axis (25) as shown in FIG. Above the passage wall, it is arranged at a position overlapping the passage wall of the intake passage (3). The EGR cooler (6) is arranged so that it does not protrude laterally outside the passage wall of the intake passage (3) when viewed in a direction parallel to the cylinder center axis (25). ing. Cooling water is introduced into the EGR cooler (6) from a water cooling jacket in the cylinder block (26), and the cooling water is led out to a cooling water pump (not shown).

  As shown in FIG. 3, the EGR valve case (7) is arranged above the passage wall of the intake passage (3), and the intake inlet pipe (5), the EGR valve case (7), and the EGR cooler (6) are moved back and forth. The EGR valve case (7) is positioned downstream of the EGR cooler (6), and the valve actuator (8) is attached to the EGR valve case (7). When the EGR valve case (7) is viewed directly above the passage wall of the intake passage (3), that is, in a direction parallel to the cylinder center axis (25) as shown in FIG. 4, the intake passage (3) Above the passage wall and at a position overlapping the passage wall of the intake passage (3). As shown in FIG. 3, the valve shaft (9a) of the EGR valve (9) made by a poppet valve is made vertical, and is slid onto the gas seal (38) in the valve shaft insertion hole (7c) in the EGR valve case (7). It is fitted in freely. As indicated by arrows in FIG. 3, the EGR gas passes through the EGR valve case (7), and the gas seal (38) is located downstream of the valve port (44) of the EGR valve (9).

  As shown in FIGS. 3 and 4, a check valve case (10) is arranged between the EGR valve case (7) and the intake inlet pipe (5), and the check valve in the check valve case (10) is arranged. The valve (10c) can prevent the inflow of intake air from the intake inlet pipe (5) to the EGR valve case (7) and the backflow of EGR gas. An in-head EGR passage (11) passing through the water-cooling jacket is provided in the cylinder head (2), and an EGR cooler (6) is disposed downstream of the in-head EGR passage (11).

  As shown in FIG. 5, the intake inlet pipe (5) and the EGR valve case are arranged in order from the rear to the front, with the front side being the front side of the engine cooling fan (14) and the rear side being the rear side. (7), EGR cooler (6) and connecting pipe (12) are arranged. As shown in FIGS. 3 and 4, the EGR valve inlet (5a) at the front of the peripheral wall of the intake inlet pipe (5) communicates with the EGR valve case outlet (7a) at the rear of the EGR valve case (7). An EGR cooler outlet (6a) at the rear end of the EGR cooler (6) is attached to the EGR valve case inlet (7b) at the front of the EGR valve case (7) so that they communicate with each other. A connection pipe outlet part (12a) at the upper rear surface of the connection pipe (12) is attached to the cooler inlet part (6b) so as to communicate with each other. The connection pipe inlet part (12b) at the lower side of the connection pipe (12) They are attached to the in-head EGR passage outlet (11a) at the front part of the lateral surface of the head (2) and communicate with each other.

  The EGR valve case (7), the EGR cooler (6), and the connecting pipe (12) are components of the rigid coupling body, and these components constitute a rigid coupling body that is not flexible. The check valve case (10) is also a component of the rigid connector, and the EGR valve case outlet (7a) at the rear of the EGR valve case (7) is connected to the check valve at the front of the check valve case (10). A case inlet part (10b) is attached to communicate these, and the check valve case outlet part (10a) on the rear surface of the check valve case (10) is connected to the EGR gas inlet part (front part of the peripheral wall of the intake inlet pipe (5)). 5a) are connected to each other, and the check valve (10c) in the check valve case (10) allows the intake air flow from the intake inlet pipe (5) to the EGR valve case (7) and the back flow of EGR gas. To be able to prevent.

  As shown in FIGS. 3 and 4, an outside-head EGR passage (13) passing outside the cylinder head (2) is led out from the intake distribution passage wall (3), and downstream of the outside-head EGR passage (13). An EGR cooler (6) is arranged, and EGR gas is introduced into the EGR cooler (6) from both the in-head EGR passage (11) and the out-head EGR passage (13).

  As shown in FIGS. 5 to 7, an outside-head EGR passage (13) is arranged behind the engine cooling fan (14), and the engine cooling caused by the engine cooling fan (14) in the outside-head EGR passage (13). The wind blows. As shown in FIG. 7, when viewed in a direction parallel to the installation direction of the crankshaft (1), the EGR passage outside the head (13) is slightly displaced from the position overlapping the engine cooling fan (14). Since the engine cooling air blowing area is larger than the locus of the outer periphery of the engine cooling fan (14), the engine cooling air blows against the head outside EGR passage (13).

  As shown in FIG. 8, a horizontally long EGR gas inlet (5a) is provided at the front of the peripheral wall of the intake inlet pipe (5), and an EGR gas inlet (5b) of a pair of left and right drill holes is provided in the EGR gas inlet (5a). ) (5c), and when viewed in a direction parallel to the central axis (16) of the intake inlet pipe (5), the front-rear imaginary line (17) passes through the central axis (16) of the intake inlet pipe (5). The center lines (25b) and (25c) of the respective EGR gas inlets (5b) and (5c) are positioned on the left and right of the cylinder), and the center line (25b) of the outer EGR gas inlet (5b) far from the cylinder head (2). The intake supply pipe connected to the intake inlet pipe (5) so that the distance from the virtual line (17) in the front-rear direction is farther from the center line (25c) of the inward EGR gas inlet (5c) near the cylinder head (2) (18) is brought close to the intake inlet pipe (5) from the cylinder head (2) side. As shown in FIGS. 5 to 7, the intake air supply pipe (18) is led out from a supercharger (30) attached to the upper part of the passage wall of the exhaust passage (4).

It is a schematic diagram which shows the flow of the intake and exhaust of the engine which concerns on embodiment of this invention, and cooling water. FIG. 2A is a cross-sectional view of an engine EGR valve case and a boost pressure cutoff valve according to an embodiment of the present invention, and FIG. 2B is a cross-sectional view of FIG. It is B line sectional drawing. It is the longitudinal cross-sectional view of the engine EGR valve case which concerns on embodiment of this invention, and the side view of the peripheral part. It is a top view of the EGR valve case of an engine concerning the embodiment of the present invention, and its peripheral parts. 1 is a side view of an engine according to an embodiment of the present invention. 1 is a plan view of an engine according to an embodiment of the present invention. 1 is a front view of an engine according to an embodiment of the present invention. 8A and 8B are views for explaining an intake distribution passage wall used in the engine according to the embodiment of the present invention, in which FIG. 8A is a left side view of a rear portion, and FIG. 8B is a cross-sectional view taken along line BB in FIG. FIG. 8C is a plan view of the rear part.

Explanation of symbols

(3) Intake passage
(5a) EGR gas inlet
(6) EGR cooler
(7) EGR valve case
(8) Valve actuator
(9) EGR valve
(9b) Energizing means for closing the valve
(20) Supercharging pressure transmission passage
(20a) Passage entrance
(30) Turbocharger
(32) Cooling water relay pipe
(34) Valve operating pressure chamber
(36) Supercharging pressure cutoff valve
(36c) Boost pressure cutoff valve case
(37) Heat input section
(49) Oil cooler
(55) Through hole
(55a) One end
(56) Inlet waterway
(57) Intermediate waterway
(58) Exit waterway

Claims (9)

A supercharger (30) driven by exhaust energy supercharges the intake passage (3), and a pneumatic valve actuator (8) is used to drive the EGR valve (9). ) Is connected to the valve operating pressure chamber (34) via the supercharging pressure transmission passage (20), and the valve actuator (8) is increased as the supercharging pressure in the intake passage (3) increases. When the valve operating pressure of the valve operating pressure chamber (34) becomes higher and the valve operating pressure of the valve operating pressure chamber (34) becomes less than a predetermined value, the EGR valve is operated by the valve closing biasing means (9b). When the valve operating state of (9) is maintained and the valve operating pressure of the valve operating pressure chamber (34) is equal to or higher than a predetermined value, the EGR valve (9) is turned on by the valve operating pressure of the valve operating pressure chamber (34). In the engine that was opened,
An engine characterized in that a passage inlet (20a) of a supercharging pressure transmission passage (20) is provided upstream of an EGR gas inlet (5a) to an intake passage (3). The engine according to claim 1,
The supercharging pressure transmission passage (20) is provided with a temperature-sensitive actuated supercharging pressure cutoff valve (36)
During a cold start when the engine temperature is less than a predetermined value, the supercharging pressure shut-off valve (36) is closed regardless of the supercharging pressure in the intake passage (3), and the EGR is operated by the valve closing urging means (9b). Keep the valve (9) closed,
When the engine temperature is higher than a predetermined value or during normal operation, the EGR valve (9) is opened and closed according to the boost pressure in the intake passage (3) by opening the boost pressure shut-off valve (36). An engine characterized by the fact that it was made to do. The engine according to claim 2,
A valve actuator (8) and a supercharging pressure cutoff valve case (36c) are attached to the EGR valve case (7), a valve cooling water passage (31) is provided in the EGR valve case (7), and the valve cooling water passage (31) is provided. An engine characterized by facing a heat input portion (37) of a supercharging pressure cutoff valve case (36c). The engine according to claim 3,
A part of the valve cooling water passage (31) is constituted by a through hole (55) provided in the EGR valve case (7), and a supercharging pressure cutoff valve case (36c) is provided at one end (55a) of the through hole (55). An engine characterized by sealing one end portion (55a) of the through hole (55) by internally fitting the heat input portion (37). The engine according to claim 4,
When the valve cooling water channel (31) is formed into a U-shape by the straight inlet water channel (56), the intermediate water channel (57), and the outlet water channel (58), the outlet water channel is formed by the through hole (55). (58) was formed, and the heat input portion (37) of the supercharging pressure cutoff valve case (36c) was fitted into one end (55a) of the outlet side water passage (58) on the intermediate water passage (57) side. An engine characterized by that. The engine according to any one of claims 1 to 5,
An oil cooler (49), an EGR cooler (6), and an EGR valve case (7), and a valve cooling water passage (31) is formed in the EGR valve case (7);
An engine comprising a water jacket of an oil cooler (49), a water jacket of an EGR cooler (6), and a valve cooling water channel (31) connected in series. The engine according to claim 6,
When the water jacket of the EGR cooler (6) and the valve cooling water channel (31) are connected in series by the cooling water relay pipe (32), the EGR cooler (6) and the EGR valve case (7) are arranged adjacent to each other. , An engine characterized by that. The engine according to claim 6 or claim 7,
An engine characterized in that cooling water is passed in the order of a water jacket of an oil cooler (49), a water jacket of an EGR cooler (6), and a valve cooling water channel (31). The engine according to any one of claims 6 to 8,
An engine comprising an EGR cooler (6) and an EGR valve case (7) arranged along the wall of the intake passage (3).

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