JP6087686B2 - EGR device for engine - Google Patents

Description

  The present invention relates to an EGR device for an engine, and more particularly to an EGR device for an engine that does not require complicated electronic control for adjusting an EGR rate.

  Conventionally, as an EGR device for an engine, there is one in which an exhaust path communicates with an intake path via an EGR path (see, for example, Patent Document 1).

According to this type of EGR device, there is an advantage that a part of the exhaust gas is recirculated to the intake air as EGR gas, and NO _X generation is suppressed.

  However, in this prior art, the engine speed and the engine load are detected, and the electronic control unit responds to the engine load based on a map and an arithmetic expression obtained by empirically obtaining an appropriate correlation between these and the EGR rate. There is a problem because the EGR rate is electronically controlled.

Japanese Patent Laying-Open No. 2005-273518 (see FIGS. 1 and 2)

<< Problem >> Complex electronic control is required to adjust the EGR rate.
The electronic control of the EGR rate according to the engine load is performed by the electronic control unit based on a map or an arithmetic expression obtained by detecting the engine speed and the engine load and experimentally obtaining an appropriate correlation between them and the EGR rate. Therefore, complicated electronic control is required to adjust the EGR rate.

  An object of the present invention is to provide an EGR device for an engine that does not require complicated electronic control for adjusting the EGR rate.

Invention specific matters of the invention according to claim 1 are as follows.
As illustrated in FIG. 3, in an engine EGR device in which an exhaust path (1) is communicated with an intake path (3) by an EGR path (2),
As illustrated in FIG. 3, a temperature-sensitive deformation member (5) that is deformed by raising and lowering the heat radiation temperature of the engine heat radiation portion (4) is provided, and the intake air of the intake passage (3) is provided in the temperature-sensitive deformation component (5). The throttle valve (6) is linked and connected,
As illustrated in FIGS. 1 (A) and 1 (B), when the heat radiation temperature of the engine heat radiating section (4) decreases due to a decrease in engine load, the temperature-sensitive deformable component (5) is deformed, and the output section associated therewith. With the displacement (5a), the opening of the intake throttle valve (6) decreases, the amount of EGR gas (8) sucked into the intake passage (3) increases, and the EGR rate increases. And
As illustrated in FIGS. 1A and 1B, when the heat radiation temperature of the engine heat radiating section (4) rises due to an increase in engine load, the temperature-sensitive deformable component (5) is deformed, and the output section accompanying this. The displacement of (5a) increases the opening of the intake throttle valve (6), reduces the amount of EGR gas (8) sucked into the intake path (3), and decreases the EGR rate.
As illustrated in FIG. 3, the engine heat radiating section (4) is a wall surface of the cylinder head (12), the EGR path (2) is an EGR outlet pipe (15), and the EGR outlet pipe (15) is a cylinder Outside the head (12), it is arranged between the exhaust path (1) and the intake path (3) ,
The intake manifold (14) constituting the intake path (1) includes an intake inlet (14a) and an intake collector (14b), and the intake collector (14b) extends in a crankshaft erection direction in a plan view of the vertical engine.
As illustrated in FIG. 3, in the plan view, the width direction of the cylinder head (12) is the left and right lateral direction, and the left and right sides of the intake manifold (14) are opposite to the side where the cylinder head (12) is located. On one side, an EGR lead pipe (15) outside the cylinder head (12) is provided along the intake collector (14b) of the intake manifold (14). An engine characterized by being provided with a length that exceeds the length of the intake collector (14b) of the manifold (14) in the direction in which the crankshaft is erected.

(Invention of Claim 1)
The invention according to claim 1 has the following effects.
<Effect> Complex electronic control is not required to adjust the EGR rate.
As illustrated in FIGS. 1 (A) and 1 (B), when the heat radiation temperature of the engine heat radiating section (4) rises or falls due to the increase or decrease of the engine load, the temperature sensitive deformable component (5) is deformed, and the output section accompanying this The displacement of (5a) increases or decreases the opening of the intake throttle valve (6), increases or decreases the amount of EGR gas (8) sucked into the intake passage (3), and increases or decreases the EGR rate. Therefore, complicated electronic control is not required for adjusting the EGR rate.

<Effect> It is possible to suppress the generation of NO _X during low load operation.
As illustrated in FIGS. 1 (A) and 1 (B), when the heat radiation temperature of the engine heat radiating section (4) decreases due to a decrease in engine load, the temperature-sensitive deformable component (5) is deformed, and the output section associated therewith. With the displacement (5a), the opening of the intake throttle valve (6) decreases, the amount of EGR gas (8) sucked into the intake passage (3) increases, and the EGR rate increases. Therefore, NO _X generation can be suppressed during low-load operation.

<Effect> PM generation is suppressed during high-load operation.
As illustrated in FIGS. 1A and 1B, when the heat radiation temperature of the engine heat radiating section (4) rises due to an increase in engine load, the temperature-sensitive deformable component (5) is deformed, and the output section accompanying this. With the displacement (5a), the opening of the intake throttle valve (6) increases, the amount of EGR gas (8) sucked into the intake passage (3) decreases, and the EGR rate decreases. Therefore, during high-load operation, incomplete combustion is suppressed and PM generation is suppressed.

(Invention of Claim 2)
The invention according to claim 2 has the following effect in addition to the effect of the invention according to claim 1.
<Effect> The EGR rate can be adjusted even when there is no power supply device such as a battery or a commercial power source.
As illustrated in FIGS. 1 (A) and 1 (B), when the heat release temperature of the engine heat dissipating part (4) rises and falls as the engine load increases and decreases, the liquid between the wax (7c) and the solid in the wax pellet (7b) is increased. Due to the phase change, the wax pellet type deformable part (7) expands and contracts, and the displacement of the output rod (7c) accompanying this causes the opening degree of the intake throttle valve (6) to increase or decrease, and EGR to the intake path (3) Since the amount of gas (8) sucked up and down increases and the EGR rate increases and decreases, the EGR rate can be adjusted even when there is no power supply device such as a battery or a commercial power source.

FIG. 1A is a diagram for explaining an EGR device for an engine according to an embodiment of the present invention. FIG. 1A is a schematic diagram showing states of a temperature-sensitive deformable part and an intake throttle valve when the cylinder head heat radiation temperature is low, and FIG. ) Is a schematic diagram showing the state of the temperature-sensitive deformable component and the intake throttle valve when the cylinder head heat dissipation temperature is high. 2A and 2B are graphs for explaining the control characteristics of the engine EGR device according to the embodiment of the present invention. FIG. 2A is a control characteristic of the opening degree of the intake throttle valve with respect to the cylinder head heat release temperature, and FIG. The control characteristic of the EGR rate with respect to temperature is shown, respectively. 1 is a schematic plan view of an engine provided with an EGR device according to an embodiment of the present invention. FIG. 4A is a diagram for explaining an engine EGR device according to a reference embodiment of the present invention, and FIG. 4A is a schematic diagram showing a state of a temperature-sensitive deformable component and an intake throttle valve when the exhaust manifold heat radiation temperature is low, and FIG. ) Is a schematic diagram showing the state of the temperature-sensitive deformable part and the intake throttle valve when the exhaust manifold heat radiation temperature is high. FIG. 5A is a graph for explaining control characteristics of an engine EGR device according to a reference embodiment of the present invention. FIG. 5A is a control characteristic of the opening degree of the intake throttle valve with respect to the exhaust manifold heat radiation temperature, and FIG. The control characteristic of the EGR rate with respect to temperature is shown, respectively. FIG. 6A is a schematic plan view of the engine, and FIG. 6B is a cross-sectional plan view of a thermoelectric device. FIG. 6A is a diagram illustrating an engine including an EGR device according to a reference embodiment of the present invention.

FIG, 4 to 6 1 to 3 for explaining the EGR device for an engine according to an embodiment of the present invention is a diagram for explaining the EGR device for an engine according to the reference embodiment of the present invention, and the embodiments In the reference embodiment , an EGR device for a vertical in-line multi-cylinder diesel engine will be described.

First, an embodiment will be described.
As shown in FIG. 3, the outline of this engine is as follows.
This engine is a vertical in-line four-cylinder engine. A cylinder head (12) is assembled to the upper part of a cylinder block (11), and an exhaust manifold (13) is assembled to one side of the cylinder head (12). An intake manifold (14) is assembled on the other side. An EGR device is assembled to this engine.

The outline of the EGR device is as follows.
As shown in FIG. 3, the exhaust path (1) communicates with the intake path (3) through the EGR path (2).
The exhaust path (1) is an exhaust manifold (13), the EGR path (2) is an EGR lead pipe (15), and the intake path (3) is an intake manifold (14). The exhaust manifold (13) includes four exhaust branches (13a), an exhaust collector (13b) extending in the crankshaft installation direction, and an exhaust outlet (13c). The intake manifold (14) includes an intake inlet (14a), an intake collector (14b) extending in the crankshaft erection direction, and four intake branches (14c). The intake inlet (14a) is provided at the front end of the intake collector (14b). The EGR outlet pipe (15) is a metal pipe, the pipe inlet (15a) is connected to the rear end of the collector (13b) of the exhaust manifold (13), and the pipe outlet (15b) is the intake inlet (14) of the intake manifold (14). 14a). The EGR lead pipe (15) is provided with a number of heat radiation fins (15c). The EGR path (2) is not provided with an EGR valve, the exhaust path (1) and the intake path (3) are always in communication with each other through the EGR path (2), and the exhaust path (1) and the intake path (3 ), The EGR gas (8) is sucked into the intake passage (3).

This engine includes a temperature-sensitive deformation member (5) that is deformed by raising and lowering the heat radiation temperature of the engine heat radiation portion (4).
As shown in FIG. 3, a temperature-sensitive deformable part (5) is attached to the engine heat dissipating part (4), and the intake throttle valve (6) of the intake passage (3) is interlocked with the temperature-sensitive deformable part (5). It is connected.
As shown in FIGS. 1 (A) and 1 (B), when the heat radiation temperature of the engine heat radiating section (4) decreases due to a decrease in engine load, the temperature-sensitive deformable component (5) is deformed, and the output section ( With the displacement 5a), the opening of the intake throttle valve (6) decreases, the amount of EGR gas (8) sucked into the intake passage (3) increases, and the EGR rate increases. .
As shown in FIGS. 1 (A) and 1 (B), when the heat radiation temperature of the engine heat radiating section (4) rises due to an increase in engine load, the temperature sensitive deformable component (5) is deformed, and the output section ( With the displacement 5a), the opening degree of the intake throttle valve (6) increases, the amount of EGR gas (8) sucked into the intake passage (3) decreases, and the EGR rate decreases. .

The engine heat radiation part (4) is a wall surface of the cylinder head (12). The intake throttle valve (6) is a butterfly valve, which is disposed at the intake inlet (14a) of the intake manifold (14), and the pipe outlet (15b) of the EGR outlet pipe (15) is opened downstream thereof.
The EGR lead pipe (15) is disposed outside the cylinder head (12) and between the exhaust path (1) and the intake path (3).
The intake manifold (14) constituting the intake path (1) includes an intake inlet (14a) and an intake collector (14b), and the intake collector (14b) extends in the crankshaft erection direction in a plan view of the vertical engine. Yes.
In the plan view, the cylinder head (12) is set to the left and right lateral direction, and the left and right sides of the intake manifold (14) are arranged on one side opposite to the side where the cylinder head (12) is located. 12) An outer EGR lead pipe (15) is provided along the intake collector (14b) of the intake manifold (14), and the EGR lead pipe (15) is seen in plan view from the intake collector (14) of the intake manifold (14). 14b) is provided with a length exceeding the length of the crankshaft erection direction.

As shown in FIGS. 1A and 1B, a wax pellet type deformable part (7) is used as the temperature sensitive deformable part (5). The wax pellet type deformable part (7) is composed of a main body (7a). The output rod (7c) is inserted into the main body (7a), the wax pellet (7b) is accommodated in the main body (7a), and the output rod (7c) is connected to the wax pellet (7b).
As shown in FIGS. 1 (A) and 1 (B), when the heat release temperature of the engine heat radiating section (4) decreases due to a decrease in engine load, the phase of the wax (7d) in the wax pellet (7b) from liquid to solid phase is reduced. With the change, the wax pellet type deformable part (7) is contracted and deformed, and the opening rod of the intake throttle valve (6) is decreased by the pulling displacement of the output rod (7c) to the main body (7a). The amount of EGR gas (8) sucked into (3) is increased, and the EGR rate is increased.
As shown in FIG. 1B, when the heat release temperature of the engine heat radiating section (4) rises due to an increase in engine load, the phase change from the solid of the wax (7d) in the wax pellet (7b) to the liquid, The wax pellet type deformable part (7) is extended and deformed, and as a result, the displacement of the output rod (7c) to the main body (7a) increases the opening of the intake throttle valve (6), and the intake path (3) The amount of the EGR gas (8) sucked into the gas is reduced, and the EGR rate is reduced.

The specific structure of the wax pellet type deformable part (7) is as follows.
As shown in FIGS. 1A and 1B, a spindle (7f) is attached to an end wall (7e) of a main body (7a), and the spindle (7f) is inserted into a wax pellet (7b). ) Is surrounded by a rubber cylinder (7g), and the rubber cylinder (7g) is surrounded by wax (7d). The wax pellet (7b) is urged toward the output rod retracting side by the urging force (7i) of the urging spring (7h). As a result of the phase change of the wax (7d) from liquid to solid, as shown in FIG. 1 (A), the volume of the wax (7d) is reduced, and the wax pellet (7b) is biased by the biasing spring (7h) ( 7i), the volume of the wax (7d) increases as shown in FIG. 1 (B) due to the phase change of the wax (7d) from the solid to the liquid. When the rubber cylinder (7g) is pressed from the periphery, the pressing part (7m) of the rubber cylinder (7g) is placed between the front end (7j) of the spindle (7f) and the front end wall (7k) of the wax pellet (7b). ) Is formed, and the wax pellet (7b) moves in the direction of coming out of the spindle (7f), and the wax pellet (7b) is positioned on the output rod extrusion side.

The control characteristics of the EGR device are as follows.
When the cylinder head heat radiation temperature decreases due to a decrease in engine load, the opening of the intake throttle valve (6) decreases as shown in FIG. 2 (A), and the EGR gas (8) flows into the intake path (3). The amount of suction increases, and the EGR rate increases as shown in FIG.
When the cylinder head heat release temperature rises due to an increase in engine load, the opening of the intake throttle valve (6) increases as shown in FIG. 2 (A), and the intake path ( The amount of EGR gas (8) sucked into 3) decreases, and the EGR rate decreases.

Next, a reference form will be described.
The reference form is configured the same as the embodiment except for the following points. Figure 4 (A) (B), in FIG. 6 (A) (B), FIG. 1, the same elements as the embodiment (A) (B), previously designated by the same reference numerals as in FIG. 3.
As shown in FIG. 6 (A), a thermoelectric element device (9) is attached to the engine heat dissipation section (4), and an electric actuator (10) is connected to the thermoelectric element device (9). Further, the intake throttle valve (6) of the intake path (3) is linked and connected.
As shown in FIGS. 4 (A) and 4 (B), when the heat radiation temperature of the engine heat radiating section (4) decreases due to a decrease in engine load, the power generation amount of the thermoelectric device (9) decreases, and the electric actuator associated therewith. Due to the displacement of the output part (10a) of (10), the opening of the intake throttle valve (6) decreases, the amount of EGR gas (8) sucked into the intake path (3) increases, and the EGR rate increases. Is configured to do.
As shown in FIGS. 4 (A) and 4 (B), when the heat radiation temperature of the engine heat radiating section (4) rises due to an increase in engine load, the power generation amount of the thermoelectric device (9) increases, and the electric actuator associated therewith Due to the displacement of the output part (10a) of (10), the opening of the intake throttle valve (6) increases, the amount of EGR gas (8) sucked into the intake path (3) decreases, and the EGR rate decreases. Is configured to do.

The contents of each component are as follows.
As shown in FIG. 6A, the engine heat radiating section (4) is a wall surface of the exhaust collector (13b) of the exhaust manifold (13). The thermoelectric device (9) is a Bezek device. 4 (A) and 4 (B), the electric actuator (10) is an electromagnetic solenoid (16), and an output rod (16b) is inserted into the main body (16a), and the output rod (16b) is inserted into the main body (16a). ) Is surrounded by the electromagnetic coil (16c), and the output rod (16b) is urged in the direction of drawing the output rod into the main body (16a) by the urging force (16e) of the urging spring (16d). When the power generation amount of the thermoelectric device (9) decreases, the pushing force of the output rod (16b) from the main body (16a) decreases, and as shown in FIG. 4 (A), the output rod ( 16b) is pulled, and the opening of the intake throttle valve (6) is decreased by the pulling displacement of the output rod (16b), the amount of EGR gas (8) sucked into the intake path (3) is increased, and EGR The rate increases. As the power generation amount of the thermoelectric device (9) increases, the pushing force of the output rod (16b) from the main body (16a) increases, and as shown in FIG. 4 (B), the output rod ( 16b) is pushed out, and the opening degree of the intake throttle valve (6) is increased by the pushing displacement of the output rod (16b), the amount of EGR gas (8) sucked into the intake passage (3) is reduced, and EGR The rate decreases.

  As shown in FIG. 6B, the thermoelectric element device (9) includes a case (9g), a low-temperature side substrate (9a) attached by closing the opening of the case (9g), and the low-temperature side substrate (9a). ) On the low temperature side electrode (9b) provided along the inner surface, the high temperature side substrate (9c) provided along the back end surface of the case (9g), and the surface of the high temperature side substrate (9c). It is composed of a high temperature side electrode (9d) provided and a thermoelectric element (9e) provided between the high temperature side electrode (9d) and the low temperature side electrode (9b), and the inside of the case (9g) is inactive. Filled with gas. This thermoelectric device (9) has a case back end wall (9f) near the high temperature side electrode (9d) attached along the engine heat radiation part (4), and a low temperature side substrate (9a) near the low temperature side electrode (9b). Is exposed in the engine room. In the thermoelectric element device (9), power is generated by the Beseck effect due to the temperature difference between the high temperature side substrate (9c) and the low temperature side substrate (9a).

The control characteristics of the EGR device are the same as in the embodiment .
When the exhaust manifold heat release temperature decreases due to a decrease in engine load, the opening of the intake throttle valve (6) decreases as shown in FIG. 5 (A), and the EGR gas (8) enters the intake path (3). The amount of suction increases and the EGR rate increases as shown in FIG.
When the exhaust manifold heat release temperature rises due to an increase in engine load, as shown in FIG. 5 (A), the opening of the intake throttle valve (6) increases, and the EGR gas (8) enters the intake path (3). The amount of suction decreases and the EGR rate decreases as shown in FIG.
The effects of the invention according to the reference form are as follows.
<Effect> Complex electronic control is not required to adjust the EGR rate.
As illustrated in FIGS. 4 (A) and 4 (B), when the heat dissipation temperature of the engine heat radiating section (4) rises and falls due to the increase / decrease in engine load, the power generation amount of the thermoelectric device (9) increases / decreases, and the accompanying actuator The displacement of the output part (10a) in (10) increases or decreases the opening of the intake throttle valve (6), increases or decreases the amount of EGR gas (8) sucked into the intake path (3), and increases or decreases the EGR rate. Therefore, complicated electronic control is not required for adjusting the EGR rate.
<Effect> It is possible to suppress the generation of NO _X during low load operation .
As illustrated in FIGS. 4A and 4B, when the heat dissipation temperature of the engine heat radiating section (4) decreases due to a decrease in engine load, the amount of power generated by the thermoelectric device (9) decreases, and the electric Due to the displacement of the output part (10a) of the actuator (10), the opening of the intake throttle valve (6) decreases, the amount of EGR gas (8) sucked into the intake path (3) increases, and the EGR rate increases. Since it is configured to increase, NO _X generation can be suppressed during low-load operation .
<Effect> PM generation is suppressed during high-load operation.
As illustrated in FIG. 4B, when the heat radiation temperature of the engine heat radiation portion (4) rises due to an increase in engine load, the power generation amount of the thermoelectric device (9) increases, and the electric actuator (10 ) Of the output portion (10a) increases the opening of the intake throttle valve (6), the amount of EGR gas (8) sucked into the intake passage (3) decreases, and the EGR rate decreases. Therefore, during high load operation, incomplete combustion is suppressed, and generation of PM is suppressed.

(1) Exhaust route
(2) EGR route
(3) Intake route
(4) Engine heat radiation part
(5) Temperature sensitive deformation parts
(5a) Output section
(6) Inlet throttle valve
(7) Wax built-in parts
(7a) Wax
(7b) Body
(7c) Output rod
(8) EGR gas
(9) Thermoelectric device
(10) Electric actuator
(10a) Output section

Claims (2)

In the engine EGR device in which the exhaust path (1) communicates with the intake path (3) by the EGR path (2).
A temperature-sensitive deformation member (5) that deforms by raising and lowering the heat radiation temperature of the engine heat radiation part (4) is provided, and the intake throttle valve (6) of the intake passage (3) is linked to this temperature-sensitive deformation part (5). And
When the heat radiation temperature of the engine heat radiating section (4) decreases due to the decrease in engine load, the temperature-sensitive deformable component (5) is deformed, and the displacement of the output section (5a) accompanying this causes the intake throttle valve (6) to move. The opening is decreased, the amount of EGR gas (8) sucked into the intake passage (3) is increased, and the EGR rate is increased.
When the heat dissipation temperature of the engine heat radiating section (4) rises due to an increase in engine load, the temperature-sensitive deformable part (5) is deformed, and the displacement of the output section (5a) accompanying this causes the intake throttle valve (6) to move. The opening is increased, the amount of EGR gas (8) sucked into the intake passage (3) is decreased, and the EGR rate is decreased.
The engine heat radiating section (4) is a wall surface of the cylinder head (12), the EGR path (2) is an EGR outlet pipe (15), and the EGR outlet pipe (15) is exhausted outside the cylinder head (12). Between the route (1) and the intake route (3) ,
The intake manifold (14) constituting the intake path (1) includes an intake inlet (14a) and an intake collector (14b), and the intake collector (14b) extends in a crankshaft erection direction in a plan view of the vertical engine.
In the plan view, the cylinder head (12) is set to the left and right lateral direction, and the left and right sides of the intake manifold (14) are arranged on one side opposite to the side where the cylinder head (12) is located. 12) An outer EGR lead pipe (15) is provided along the intake collector (14b) of the intake manifold (14), and the EGR lead pipe (15) is seen in plan view from the intake collector (14) of the intake manifold (14). The engine is provided with a length exceeding the length of the crankshaft erection direction of 14b). The engine EGR device according to claim 1,
A wax pellet type deformable part (7) is used as the temperature sensitive deformable part (5). The wax pellet type deformable part (7) has an output rod (7b) inserted into the main body (7a), and the main body (7a ) Contains wax pellets (7b), and an output rod (7c) is connected to the wax pellets (7b).
When the heat radiation temperature of the engine heat radiation part (4) decreases due to the decrease in engine load, the wax pellet type deformable part (7) shrinks due to the phase change from liquid to solid of the wax (7c) in the wax pellet (7b). Due to the deformation, the pulling displacement of the output rod (7c) to the main body (7b) reduces the opening of the intake throttle valve (6), and the amount of EGR gas (8) sucked into the intake path (3) Is configured to increase the EGR rate,
When the heat dissipation temperature of the engine heat dissipation part (4) rises due to an increase in engine load, the wax pellet type deformable part (7) expands due to the phase change of the wax (7c) in the wax pellet (7b) from solid to liquid. Due to the deformation, the displacement of the output rod (7c) to the main body (7b) is increased, and the opening of the intake throttle valve (6) increases, and the amount of EGR gas (8) sucked into the intake passage (3). An EGR device for an engine, characterized in that the EGR rate decreases and the EGR rate decreases.

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