JP2016044582A - Warming-up device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a warming-up device for an internal combustion engine, capable of improving the fuel efficiency of the internal combustion engine even after warmed up by reducing the viscosity of oil in sliding parts such as a journal part of a crankshaft and a connecting rod connection part in a medium-low load torque region.SOLUTION: The warming-up device includes an exhaust gas jacket 2 provided on the side wall of a cylinder block 11, an EGR pipe 24 connected to an EGR circuit 50 for taking in part of exhaust gas and supplying part of the taken-in exhaust gas, a three-way valve 3 arranged in the EGR pipe 24 for switching part of the taken-in exhaust gas between the EGR circuit 50 and the exhaust gas jacket 2, and a valve control device 5B for performing switching control of the three-way valve 3. The valve control device 5B performs switching operation into a position for distributing/shutting off the exhaust gas to/from the exhaust gas jacket 2 and the EGR circuit 50, a position for distributing it only to the exhaust gas jacket 2, or a position for distributing it only to the EGR circuit 50, on the basis of a revolving speed N and a load torque T of an engine 1.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an internal combustion engine warm-up device for promoting warm-up of an internal combustion engine in a vehicle.

In general, an internal combustion engine (hereinafter referred to as an engine) in a cold state requires a certain amount of time from the start of the engine to a warm-up state where normal output is achieved.
If the engine warm-up is poor, the viscosity (physical properties) of the oil, which is the engine lubricant, is high, and the friction between the piston and cylinder and in the sliding part such as the journal part of the crankshaft is large, resulting in poor fuel consumption. Was inducing.
In order to reduce the viscosity of oil at an early stage, it has been proposed to warm a cylinder block or the like with the heat of engine exhaust gas.

For example, Patent Document 1 discloses an exhaust lead-out pipe that branches exhaust gas from an exhaust manifold, a block introduction pipe that guides exhaust gas to an in-block exhaust passage provided below a lower water jacket in the engine block, and an exhaust lead-out pipe. And an out-block passage that guides exhaust gas to the intake passage as high-pressure EGR.
The exhaust lead-out pipe, the block introduction pipe, and the outside block passage are connected by a three-way valve switching valve.
During the warm-up, the three-way valve switching valve allows the exhaust outlet pipe and the block introduction pipe to communicate with each other, and the exhaust outlet pipe and the outside block passage are blocked.
After the warm-up, the three-way valve switching valve communicates the exhaust outlet pipe and the outside block passage, and the exhaust outlet pipe and the block inlet pipe are shut off.
By doing in this way, the lower part of a cylinder can be warmed up by making exhaust gas flow into the exhaust passage in a block.

Further, Patent Document 2 discloses a heating means (gas jacket) for heating at least the vicinity of the piston bottom dead center of the cylinder wall, a cooling means (gas jacket) for cooling the vicinity of the bottom dead center, and detecting the temperature of the cylinder wall. If the temperature is lower than the target temperature, flow exhaust gas through the gas jacket to increase the temperature of the cylinder wall to reduce the viscosity of the lubricating oil (oil). Introduce fresh air into the gas jacket to lower the temperature of the cylinder wall and prevent the oil film from running out.
Then, the heat exchanged exhaust gas is reused as EGR.

JP 2008-285997 A JP 2001-152960 A

According to Patent Document 1, after the warm-up, the switching valve of the three-way valve allows the exhaust outlet pipe and the block outer passage to communicate with each other, and the exhaust outlet pipe and the block inlet pipe are shut off.
Therefore, the exhaust gas cannot flow through the in-block exhaust passage.
For this reason, after warming up, it has a structure that cannot continue warming up with exhaust gas, reducing the oil viscosity of each sliding part such as the journal part of the crankshaft and the connecting rod connecting part in the medium and low load torque range As a result, it is not possible to obtain the fuel efficiency improvement effect accompanying the decrease in engine internal resistance.
Further, Patent Document 2 does not disclose a switching valve that switches to a gas jacket and an EGR circuit.
Therefore, even after warm-up, depending on the operating condition of the engine, by continuing warm-up of the lower part of the engine, the viscosity of the oil is reduced, the internal resistance during engine operation is reduced, and fuel efficiency cannot be improved.

  In view of these problems, the object of at least one embodiment of the present invention is to provide the oil viscosity of each sliding portion such as the journal portion of the crankshaft and the connecting rod connecting portion in the medium and low load torque region even after the internal combustion engine is warmed up. The purpose is to improve the fuel consumption of the internal combustion engine.

An internal combustion engine warm-up device according to at least one embodiment of the present invention is an internal combustion engine warm-up device,
An exhaust gas jacket that is provided on a side wall of a cylinder block of the internal combustion engine and that heats the cylinder block by introducing exhaust gas therein, and an exhaust gas intake port that takes in a part of the exhaust gas. An EGR pipe that is connected to a circuit and supplies a part of the taken-in exhaust gas, and a three-way valve that is disposed in the EGR pipe and switches a part of the taken-in exhaust gas to the EGR circuit of the internal combustion engine and the exhaust gas jacket And a valve control device that performs switching control of the three-way valve, and the valve control device distributes the exhaust gas to the exhaust gas jacket and the EGR circuit based on the rotational speed and load torque of the internal combustion engine. The three-way valve is switched to a position to perform or block, a position to flow only to the exhaust gas jacket, and a position to flow only to the EGR circuit. To.

According to such a configuration, by providing the three-way valve in the EGR pipe, the lower part of the cylinder block (the part close to the crankshaft) is depending on the operating state of the internal combustion engine even during and after the internal combustion engine is warmed up. Warm-up with exhaust gas and exhaust gas purification with EGR can be performed simultaneously.
Therefore, the viscosity of the oil in each sliding portion inside the internal combustion engine can be kept low, and fuel consumption can be improved by reducing the internal resistance.
Further, by providing a three-way valve in the EGR pipe, it is possible to omit separately connecting a pipe for flowing exhaust gas to the exhaust gas jacket to the exhaust pipe downstream of the exhaust manifold, thereby connecting the pipe to the exhaust pipe. For example, the layout of the connecting member and the piping for the purpose can be simplified, and the durability reliability can be improved and the cost can be reduced by the simplification.

  Further, in some embodiments, the valve control device is configured to reduce the load torque when the rotation speed of the internal combustion engine is in a low / medium speed rotation speed region and the load torque is in a low torque region, or in a high speed rotation region. A first switching control unit is provided for switching the three-way valve to a position where the exhaust gas is circulated only to the exhaust gas jacket in the middle torque region.

  According to such a configuration, when the load torque of the internal combustion engine is low as in the first region of FIG. 4 or when the rotational speed of the internal combustion engine is high and the load is medium load, the cylinder block is formed by the exhaust gas jacket. By warming up the lower part of the engine, the viscosity of the oil is reduced and the fuel consumption of the internal combustion engine is improved.

  Further, in some embodiments, the valve control device is configured such that when the rotation speed of the internal combustion engine is in a low / medium speed rotation speed region and a load torque is in a medium load torque region, the exhaust gas is discharged to the exhaust gas jacket and the EGR circuit. It has the 2nd switching control part which switches the said three-way valve to the position which distribute | circulates to a.

  According to such a configuration, when the internal combustion engine is in a low / medium speed rotation speed region and a medium load as in the second region of FIG. 4, the exhaust gas is circulated through both the exhaust gas jacket and the EGR circuit, By warming up the lower part of the cylinder block, the viscosity of the oil is reduced, the fuel consumption of the internal combustion engine is improved, and exhaust gas is supplied to the intake passage side to enable exhaust gas purification (NOx reduction).

  In some embodiments, the valve control device distributes exhaust gas only to the EGR circuit when the rotational speed of the internal combustion engine is in a low / medium speed rotational speed region and the load torque is in a high load torque region. It has a 3rd switching control part which switches the said three-way valve to a position, It is characterized by the above-mentioned.

  According to such a configuration, as shown in the third region of FIG. 4, when the internal combustion engine is in a low / medium speed rotational region and a high load, the amount of heat generated by the operation of the internal combustion engine increases. The warming-up due to this is stopped to prevent combustion knocking, and exhaust gas purification (NOx reduction) is made possible by circulating only in the EGR circuit.

  In some embodiments, the valve control device distributes exhaust gas along with the exhaust gas jacket and the EGR circuit when the rotational speed of the internal combustion engine is in a high rotational speed region and the load torque is in a high load torque region. It has a 4th switching control part which switches the said three-way valve to the position to interrupt | block.

  By doing so, the exhaust gas temperature rises when the internal combustion engine is in a high rotation region and a high load torque region as in the fourth region of FIG. 4. Viscosity drops excessively, and there is a risk of seizure of sliding parts such as cylinders, pistons, piston rings, connecting rods, piston pins, crankpins, crankshaft journals, etc., which can be prevented. .

  In some embodiments, when the temperature of engine oil rises above a threshold, the flow of exhaust gas to the exhaust gas jacket is blocked.

  According to such a configuration, since the temperature of the engine oil is directly detected and determined, the oil temperature is excessively increased, the oil viscosity is excessively decreased, and the deterioration of fuel consumption due to the increase of the sliding resistance of each sliding portion is surely ensured. Can be prevented. Furthermore, since there is a risk of seizure of each sliding portion, it can be reliably prevented.

  According to at least one embodiment of the present invention, even during warm-up and after warm-up, the oil viscosity of each sliding portion such as the crank journal portion and the connecting rod connecting portion in the medium and low load torque region is reduced, An internal combustion engine capable of improving the fuel consumption of the internal combustion engine can be provided.

1 shows an overall schematic configuration diagram according to a first embodiment of the present invention. FIG. (A) is a side view in the cylinder block attachment state of the exhaust gas jacket of FIG. 1, (B) shows AA sectional drawing of (A). The external appearance schematic perspective view of the apparatus which has arrange | positioned the three-way valve in the intermediate part of the EGR piping which concerns on 1st Embodiment of this invention is shown. It is explanatory drawing which shows an example of the exhaust gas distribution control map of the three-way valve which concerns on 1st Embodiment of this invention. (A) is a schematic view of a schematic arrangement position of the three-way valve 3 and a piping situation joined to the three-way valve 3, and (B) is a switching supply destination of exhaust gas at each switching position along (A). A list is shown. It is a control flow of the valve control apparatus of 1st Embodiment. It is a block diagram of the configuration of the valve control device of the first embodiment. It is a block diagram of the configuration of the valve control device of the second embodiment. It is a control flow of the valve control apparatus of 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to specific examples unless otherwise specifically described. Only.

(First embodiment)
FIG. 1 is a schematic diagram showing the overall configuration of a first embodiment of the present invention.
Reference numeral 1 denotes an in-cylinder injection internal combustion engine equipped with a catalyst temperature raising device for a multi-cylinder internal combustion engine.
This cylinder injection internal combustion engine 1 (hereinafter abbreviated as engine 1) is a spark ignition type four-cycle engine.

  The engine 1 includes a cylinder block 11, a cylinder head 13 that closes an upper portion of the cylinder block 11, a piston 17 that slides vertically along a cylinder 11 b in the cylinder block 11, a crankshaft 18, and a piston 17 And the crankshaft 18 are connected to each other so that the reciprocating motion of the piston 17 is converted into a rotational motion by the crankshaft 18 and disposed at the lower end of the cylinder block 11. An oil pan 19 for storing oil to be lubricated or cooled.

The oil is pumped to each sliding contact portion by an oil pump (not shown).
The cylinder block 11 is integrally formed with a crankcase 12 that pivotally supports a crankshaft 18 that converts a vertical motion of the piston 17 into a rotational motion and outputs it at a lower portion.
A combustion chamber CC is formed by the lower surface of the cylinder head 13, the cylinder 11 b and the upper surface of the piston 17.

  The cylinder block 11 is provided with a water jacket 11a through which engine coolant circulates along the outer periphery of the cylinder 11b in order to maintain the temperature of the engine 1 at an appropriate temperature. An exhaust gas jacket 2 for introducing exhaust gas and heating the lower region of the cylinder block 11 is provided below the water jacket 11a.

2A is a side view of the exhaust gas jacket 2 of FIG. 1 with the cylinder block 11 attached, and FIG. 2B is a cross-sectional view taken along the line AA of FIG.
The exhaust gas jacket 2 is arranged on the outer wall surface along the cylinder arrangement direction of the cylinder block 11 from the vicinity of the lower end edge of the water jacket 11 a to the vicinity of the upper portion of the crankcase 12.
The size of the exhaust gas jacket 2 in the crankshaft axial direction is substantially equal to the length of the crankshaft 18.

The exhaust gas jacket 2 is provided on the side of the cylinder block 11 where the exhaust manifold 14 (hereinafter abbreviated as “exhaust manifold 14”) is disposed.
The exhaust gas jacket 2 is formed with an annular wall portion 12 a that protrudes outward from the outer surface of the cylinder block 11.
A lid member 23 that covers the entire circumference of the top portion is fastened to the top portion (protruding tip) of the annular wall portion 12a with a plurality of bolts 23b via packings 23a.

The lid member 23 has an introduction adapter 26 to which an exhaust gas introduction pipe 21 (see FIG. 1) for introducing exhaust gas into the waste heat warm-up space EH of the exhaust gas jacket 2 is attached, and is introduced into the waste heat warm-up space EH. A lead-out adapter 27 to which an exhaust gas lead-out pipe 22 (see FIG. 1) for leading the exhaust gas exhausted to the downstream side of the manifold catalytic converter 15 is attached is provided.
The introduction adapter 26 is disposed closer to the crankshaft 18 (lower side in the case of FIG. 2B), and the outlet adapter 27 is closer to the water jacket 11a (upper side in the case of FIG. 2B). It is arranged.
This is because an oil pan 19 in which a large amount of oil is stored from a manifold catalytic converter 15 (hereinafter abbreviated as a catalytic converter 15), which is an exhaust gas purifying device, and a journal portion of a crankshaft (not shown). ) In order to quickly warm up and reduce the viscosity of the oil.

The cylinder head 13 further includes an intake port 13f for introducing fresh air into the combustion chamber CC, an intake valve 13b for opening and closing the intake port, a fuel injection nozzle 13d for injecting fuel into the combustion chamber CC, and the combustion chamber CC. Spark plug 13c for burning a mixture of air and fuel, an exhaust port 13e for leading the combustion gas combusted in the combustion chamber CC (hereinafter abbreviated as exhaust gas) to the outside of the engine 1, and opening and closing the exhaust port 13e An exhaust valve 13a is disposed.
Further, the cylinder head 13 has an inlet manifold 13h formed with an intake passage 13g connected to the intake port 13f and through which fresh air flows, and an exhaust manifold 14 formed with an exhaust passage 14e connected to the exhaust port 13e and led out exhaust gas. The manifold catalytic converter 15 directly connected to the exhaust manifold 14 is connected.

The EGR pipe 24 according to the first embodiment of the present invention is shown as an example of a low-pressure EGR pipe that takes out exhaust gas from the downstream side of the manifold catalytic converter 15, and FIG. 3 shows a three-way valve at an intermediate portion of the low-pressure EGR pipe 24. FIG.
One end of the exhaust manifold 14 is attached to the cylinder head 13, and the catalytic converter 15 is directly connected to the other end.
The exhaust manifold 14 is attached to the cylinder head 13 and has an attachment base portion 14b on one end side having an opening (the number of openings is the same as the number of cylinders) through which exhaust gas passes at a position corresponding to the exhaust port 13e, and the attachment base. Each deriving portion 14c communicates with an opening through which the exhaust gas passes through the portion 14b, and the exhaust portion 14c flows and the collecting portion 14a that is the other end side that collects the exhaust gas from each deriving portion 14c.

A catalytic converter 15 is directly connected to the lower surface (see FIG. 3) of the collecting portion 14a of the exhaust manifold 14.
The lower end side of the catalytic converter 15 (see FIG. 3) is provided with a lower cone 15b formed in a substantially conical shape while the exhaust gas flow path of the exhaust gas purified by the catalyst 15a (see FIG. 1) changes at a substantially right angle in the lower part. Has been.
An upstream exhaust pipe 15c is formed integrally with the lower cone 15b at the discharge end of the lower cone 15b.
A universal joint 16 connected to the upstream side exhaust pipe 15c and the downstream side exhaust pipe 29 is disposed at the tip of the upstream side exhaust pipe 15c.
In the universal joint 16, the downstream exhaust pipe 29 is supported on the vehicle body side (not shown), and the upstream exhaust pipe 15 c is supported on the cylinder block 11 via the catalytic converter 15 and the exhaust manifold 14. It is arranged to absorb the oscillation of the displacement.

Further, on the lower surface side of the lower cone 15b (see FIG. 3), an exhaust gas inlet 24a of a low pressure EGR pipe 24 for introducing exhaust gas for the EGR circuit 50 and the exhaust gas jacket 2 protrudes into the exhaust gas flow path in the lower cone 15b. Is provided.
Further, the exhaust gas inlet 24a has an inclined opening 24b whose tip is cut obliquely, and the inclined opening 24b is disposed so as to face the upstream side of the exhaust gas passage.
By making the inclined opening 24b face the upstream side of the exhaust gas flow path, the amount of exhaust gas taken in from the exhaust gas inlet 24a is increased by using the fluid pressure of the exhaust gas.
The exhaust gas outflow side of the low-pressure EGR pipe 24 is connected to an EGR circuit 50 that supplies exhaust gas to an intake passage 13g of the engine via a flow path 13i formed in the cylinder head 13.
In the present embodiment, the front end of the exhaust gas inlet 24a is cut obliquely, and the cut inclined opening 24b is disposed so as to face the upstream side of the exhaust gas flow path. May be bent toward the upstream side of the exhaust gas flow path to receive the ram pressure of the exhaust gas flow.

A three-way valve 3 is disposed in the middle in the length direction of the low pressure EGR pipe 24.
The three-way valve 3 includes an upstream low-pressure EGR pipe 241 having an exhaust gas inlet 24 a, a downstream low-pressure EGR pipe 242 that supplies exhaust gas to the flow path 13 i in the cylinder head 13, and an introduction adapter 26 for the exhaust gas jacket 2. An exhaust gas introduction pipe 21 connected to is connected.
In the present embodiment, the three-way valve 3 is arranged in the middle portion in the longitudinal direction of the low pressure EGR pipe 24. However, even if the three-way valve is arranged in the middle portion in the longitudinal direction of the exhaust gas introduction pipe 21, It is substantially the same.
Further, in the present embodiment, the three-way valve 3 is disposed in the middle portion of the low pressure EGR pipe 24. However, it can be similarly disposed in a high pressure EGR pipe (not shown).

  Further, as described above, the waste heat warm-up space EH is provided on the side where the exhaust manifold 14 is provided, and the exhaust gas inlet 24a of the low-pressure EGR pipe 24 is provided below the lower cone 15b. Thus, the length of the exhaust gas introduction pipe 21 to the exhaust gas jacket 2 can be shortened, and the effect of improving the warm-up effect by the waste heat warm-up space EH can be obtained by suppressing the decrease in the exhaust gas temperature as much as possible. Can do.

The upstream exhaust pipe 15c is connected to the oxygen concentration sensor mounting adapter 15e and the end of the exhaust gas outlet pipe 22 for returning the exhaust gas from the waste heat warm-up space EH of the exhaust gas jacket 2 to the upstream exhaust pipe 15c. A return adapter 15d is provided.
The return adapter 15d is disposed between the mounting adapter 15e of the oxygen concentration sensor (not shown) and the universal joint 16.
The position of the return adapter 15d is set as downstream as possible from the exhaust gas inlet 24a in order to improve the circulation of the exhaust gas by the differential pressure between the exhaust gas inlet 24a and the position of the return adapter 15d.
Further, the return adapter 15d is positioned downstream of the oxygen concentration sensor mounting adapter 15e in order to avoid an influence on the oxygen concentration sensor (not shown).
The reason why the mounting adapter 15e and the return adapter 15d are arranged on the upstream side of the universal joint 16 is that, as described above, the mounting adapter 15e and the return adapter 15d are supported on the engine 1 side. This is to absorb the fluctuation of the relative displacement.

Next, the control device 5 will be described. An engine control device 5A that controls the operation of the engine 1 and a valve control device 5B that controls switching of the three-way valve 3 are provided.
The valve control device 5B includes a detection signal of the rotation speed sensor 52 that detects the rotation speed N of the engine 1, a detection signal of the load torque sensor 51 that detects the amount of depression of the accelerator pedal 51a as the load torque T of the engine 1, The detection signal of the oil temperature sensor 53 that detects the temperature of the oil stored in the oil pan 19 is input.

Further, the valve control device 5B includes a first switching control unit 56, a second switching control unit 57, a third switching control unit 58, and a fourth switching control unit 59 as shown in FIG. .
The first switching control unit 56 loads the engine 1 when the engine speed N is in the low and medium speed engine speed range and the load torque T is in the low torque area, or in the high speed engine speed area. When the torque is in the low-medium torque region, the three-way valve 3 is switched to the first switching position where the exhaust gas is circulated only to the exhaust gas jacket 2.
Further, the second switching control unit 57 converts the exhaust gas into the exhaust gas jacket 2 when the engine speed N of the engine 1 is in the low and medium speed engine speed region and the load torque is in the medium load torque region as in the second region of FIG. And the switching operation of the three-way valve 3 is performed to the 2nd switching position which distribute | circulates from the EGR piping 24 to the intake passage side.

  The third switching control unit 58 distributes the exhaust gas only to the EGR circuit when the engine speed N is in the low / medium engine speed region and the load torque T is in the high load torque region as in the third region of FIG. The three-way valve 3 is switched to the third switching position.

  Further, the fourth switching control unit 59, when the rotational speed N of the engine 1 is in the high rotational speed region and the load torque T is in the high load torque region as in the fourth region in FIG. The switching operation of the three-way valve 3 is performed at the fourth switching position where the circuit is shut off.

FIG. 4 shows an example of the switching control map of the three-way valve 3 according to the embodiment of the present invention, and FIG. 5 (A) shows the schematic arrangement position of the three-way valve 3 and the piping situation joined to the three-way valve 3. FIG.
FIG. 5B shows an exhaust gas supply destination switching list at each switching operation position along FIG.
FIG. 5 shows an example of a schematic diagram for explaining the switching state of the exhaust gas flow path with respect to the switching position of the three-way valve 3, and FIG. 6 shows an example of a control flow of exhaust gas switching.
In the map of FIG. 4, the horizontal axis represents the engine speed Nrpm, and the vertical axis represents the engine torque (load torque) Tkgm. The low rotation region, medium rotation region, and high rotation region on the horizontal axis are regions obtained by dividing the operable rotation speed region (maximum rotation speed) into approximately three equal parts, and the low load torque region, medium load torque region on the vertical axis, Similarly, the high load torque region is a region obtained by dividing the operable torque region (maximum torque) into approximately three equal parts.

By switching the three-way valve 3, there are four exhaust gas supply patterns.
The three-way valve 3 is supplied to the exhaust gas jacket 2 and the low pressure EGR circuit by being operated to the exhaust gas jacket 2 by being operated to the first switching position, and being operated to the second switching position. Exhausted by the low pressure EGR pipe 24 by being operated to the second region, the third region supplied only to the low pressure EGR circuit by being operated to the third switching position, and being operated to the fourth switching position. And a fourth region for shutting off.
Switching control of the three-way valve 3 is performed by a valve control device 5B.
As described above, the valve control device 5B is implemented based on output signals detected by the rotation speed sensor 52 of the engine 1 and the load torque sensor 51 of the engine 1.

An example of switching control of the three-way valve 3 by the valve control device 5B will be described along the control flow of FIG.
Start in step S1.
In step S2, the engine rotational speed Nrpm from the rotational speed sensor 52 of the engine 1 and the detection signal of the load torque Tkg-m by the accelerator pedal 51a are taken in.
In step S3, it is determined whether the operating state of the engine 1 satisfies the following conditions.
The rotational speed N is the rotational speed N1 ≦ N <the rotational speed N3, and the load torque T is T ≦ the load torque T1 (provided that the rotational speed N1 is a low-speed rotational speed in an engine operating state higher than idling).

  That is, if it is determined that the engine speed N is in the low speed range or medium speed range and the load torque is in the low load torque range equal to or lower than T1, YES is selected and step S4 is entered. Then, the three-way valve 3 is switched to the first switching position (the first switching position in FIG. 5B) so that the exhaust gas flows through the exhaust gas jacket 2. Then, it progresses to step S11 and returns.

If NO is selected in step S3, the process proceeds to step S5.
In step S5, it is determined whether the operating state of the engine 1 satisfies the following conditions.
The rotational speed N is the rotational speed N3 ≦ N ≦ the rotational speed N4, and the load torque T is T <load torque T2 (where the rotational speed N1 <the rotational speed N3 <the rotational speed N4 (Max) and the load torque T1 < Load torque T2).

That is, when it is determined that the rotational speed is in the high speed rotational speed region and the load torque is in the region of less than T2, YES is selected and the process proceeds to step S4, and the three-way valve 3 is moved to the first switching position (FIG. 5 ( B) is switched to the first switching position) so that the exhaust gas flows through the exhaust gas jacket 2. Then, it progresses to step S11 and returns.

  In this way, when the load torque T of the engine 1 is low, or when the rotational speed N of the engine 1 is high and the load is medium load, the three-way valve 3 is introduced into the upstream-side low-pressure EGR pipe 241. By flowing the exhaust gas only through the exhaust gas jacket 2 and warming up the lower part of the cylinder block 11, the oil viscosity can be reduced and the fuel consumption of the engine 1 can be improved.

If NO is selected in step S5, the process proceeds to step S6.
In step S6, it is determined whether the operating state of the engine 1 satisfies the following conditions.
The rotational speed N is the rotational speed N1 ≦ N <the rotational speed N3, and the load torque T is the load torque T1 ≦ T <load torque T2.

That is, if it is determined that the rotational speed N is in the high speed rotational speed region and the load torque T is in the region of T1 to T2, YES is selected and the process proceeds to step S7.
In step S7, the three-way valve 3 is operated to the second switching position (second switching position in FIG. 5B), and the process proceeds to step S11.

In this way, when the engine 1 has a low speed or medium speed N1 ≦ N <speed N3 and the load torque T is in the medium load torque region, the exhaust gas is discharged into the exhaust gas jacket 2 and the downstream low-pressure EGR pipe 242. , The lower part of the cylinder block 11 is warmed up to lower the viscosity of the oil, improve the fuel consumption of the engine 1 and exhaust gas into the downstream low-pressure EGR pipe 242 connected to the intake path. Is circulated to enable exhaust gas purification (NOx reduction).
Also in this case, since the load torque T is relatively small (less than T2 kg-m), there is no fear of combustion knocking even if the lower part of the cylinder block 11 is warmed up.

  Further, if NO is selected in step S6, the process proceeds to step S8.

In step S8, it is determined whether the operating state of the engine 1 satisfies the following conditions.
The rotational speed N is the rotational speed N1 ≦ N ≦ the rotational speed N2, and the load torque T is T ≧ load torque T2 (where the rotational speed N2 <the rotational speed N3).
In the case of YES, the process proceeds to step S9, the three-way valve 3 is operated to the third operation position (the third switching position in FIG. 5B), and the process proceeds to step S11.

In this way, when the rotational speed N of the engine 1 is the rotational speed N1 ≦ N ≦ the rotational speed N2 in the low to medium speed range and the load torque T is T ≧ torque T2 in the high load torque region, the engine 1 Therefore, when the engine speed is lower than the engine speed in the second region (the engine speed N2 <the engine speed N3), the exhaust gas is not warmed up to prevent knocking of combustion, and the intake air Exhaust gas purification (NOx reduction) is promoted by increasing the amount of exhaust gas supplied to the downstream low-pressure EGR pipe 242 connected to the path.
In the switching control map of FIG. 4, the difference is set such that the rotational speed N of the third region is the rotational speed N2 <the rotational speed N3. The region where knocking is likely to occur when the engine 1 is at a high load. Therefore, the prevention of knocking is made safer by lowering the rotational speed N.

Further, if NO is selected in step S8, the process proceeds to step S10, the three-way valve 3 is switched to the fourth switching position (the fourth switching position in FIG. 5B), and the process proceeds to step S11.
If NO is selected in step S8, it is determined that the operating state of the engine 1 is in the following condition.
The rotational speed N is the rotational speed N2 <N, and the load torque T is the load torque T2 <T.

In this case, since the engine 1 has high torque and high rotation, the cylinder block 11 becomes hot and the sliding of the journal portion of the crankshaft 18 and the connecting rod connecting portion due to knocking and excessive decrease in oil viscosity. In order to prevent seizure of the parts, the exhaust gas circulation to the EGR circuit 50 is blocked so that the exhaust gas jacket 2 from the three-way valve 3 and the low pressure EGR are not operated.

By providing the three-way valve 3 at the intermediate portion of the low-pressure EGR pipe 24 in this way, the load torque T is lower than the cylinder block 11 (close to the crankshaft 18) in the low / medium load torque region even after the warm-up is completed. Part) can be warmed up by exhaust gas.
Therefore, the viscosity of the oil in each sliding portion such as the journal portion of the crankshaft 18 and the connecting rod connecting portion in the middle and low load torque region can be kept low, and the fuel efficiency can be improved by reducing the internal resistance.
Further, by providing the three-way valve 3 in the low-pressure EGR pipe 24, it is possible to omit separately connecting a pipe for flowing exhaust gas to the exhaust gas jacket 2 to the lower cone 15b on the downstream side of the exhaust path of the exhaust manifold, and connecting the pipe to the exhaust pipe. Therefore, simplification of the layout of the connecting member and the piping, etc. is achieved, and the durability and reliability can be improved and the cost can be reduced by the simplification.

  Note that the control of the valve control device 5B of the first embodiment described above is performed regardless of whether or not the engine has been warmed up, that is, during the warming up and after the warming up, according to the operating conditions of the engine speed and the engine load. Although it is controlled based on this, it is of course possible to execute the control until the completion of warming up of the engine. In this case, promotion of warming up of the engine can be effectively obtained.

(Second Embodiment)
Next, FIG. 8 shows a valve control device 5C as another example of the valve control device 5B. The control flow will be described with reference to FIG.
The second embodiment is characterized in that, in addition to the first embodiment, the supply of exhaust gas to the exhaust gas jacket 2 is stopped when the temperature of the engine oil rises above a threshold value.

As shown in FIG. 8, the valve control device 5C includes an oil temperature in addition to the first switching control unit 56, the second switching control unit 57, the third switching control unit 58, and the fourth switching control unit 59. A determination unit 55 is provided.
The oil temperature determination unit 55 determines that the heating by the exhaust gas jacket 2 is completed when the detection signal of the oil temperature sensor 53 that detects the temperature of the oil stored in the oil pan 19 reaches a threshold temperature. The exhaust gas supply to the exhaust gas jacket 2 is stopped.
As this threshold temperature, the oil temperature is excessively increased, the oil viscosity is excessively decreased, and there is a risk of increasing the sliding resistance in each sliding portion such as the journal portion of the crankshaft and the connecting rod connecting portion. It is set as temperature.

In FIG. 9, steps S1 to S11 are the same as those in the first embodiment, and thus the same reference numerals are given and description thereof is omitted.
In the case of Yes determination in step S3, in step S21, the valve control device 5C determines whether or not the detected temperature OT of the oil temperature sensor 53 is detected temperature OT <threshold temperature OTS. In step S22, the three-way valve 3 is switched to the fourth switching position to block the introduction of the exhaust gas into the exhaust gas jacket 2. In the case of Yes, it progresses to step S4 and switches the three-way valve 3 to a 1st switching position.

  Similarly, in the case of Yes determination in step S6, in step S23, the valve control device 5C determines whether or not the detected temperature OT of the oil temperature sensor 53 is detected temperature OT <threshold temperature OTS. In this case, in step S9, the three-way valve 3 is switched to the third switching position to cut off the introduction of the exhaust gas into the exhaust gas jacket 2 and supply only to the EGR circuit 50. In the case of Yes, it progresses to step S7 and switches the three-way valve 3 to a 2nd switching position.

  According to the second embodiment, even in a low load and medium load torque state, the oil temperature may rise excessively during long-term operation, and the oil viscosity may be excessively reduced. It is possible to reliably prevent deterioration in fuel consumption due to increase in sliding resistance of the sliding portion. Furthermore, it is possible to reliably prevent the possibility of seizure of each sliding portion.

  The present invention can be used for an internal combustion engine warm-up device and an exhaust gas purification device for promoting warm-up of an internal combustion engine in a vehicle.

1 engine (internal combustion engine)
2 exhaust gas jacket 3 three-way valve 5 control device 5A engine control device 5B, 5C valve control device 11 cylinder block 11a water jacket 12 crankcase 12a annular wall 13 cylinder head 15 catalytic converter (manifold catalytic converter)
15c Upstream exhaust pipe 18 Crankshaft 22 Exhaust gas outlet pipe 23 Lid member 23a Packing 24 Low pressure EGR piping (EGR piping)
24a Exhaust gas inlet 24b Inclined opening 50 EGR circuit 51 Load torque sensor 52 Speed sensor 53 Oil temperature sensor 55 Oil temperature determination unit 56 First switching control unit 57 Second switching control unit 58 Third switching control unit 59 Fourth switching Control unit 241 Upstream low pressure EGR piping 242 Downstream low pressure EGR piping CC Combustion chamber EH Waste heat warm-up space

Claims (6)

In a warm-up device for an internal combustion engine,
An exhaust gas jacket that is provided on the side wall of the cylinder block of the internal combustion engine and that heats the cylinder block by introducing exhaust gas into the interior;
An EGR pipe having an exhaust gas inlet for taking in a part of the exhaust gas, connected to the EGR circuit of the internal combustion engine, and supplying a part of the taken-in exhaust gas;
A three-way valve that is disposed in the EGR pipe and switches a part of the taken-in exhaust gas to the EGR circuit of the internal combustion engine and the exhaust gas jacket, and a valve control device that performs switching control of the three-way valve,
The valve control device, based on the rotational speed and load torque of the internal combustion engine, a position where the exhaust gas is circulated to or cut off from the exhaust gas jacket and the EGR circuit, a position where only the exhaust gas jacket is circulated, and the EGR A warming-up device for an internal combustion engine, wherein the three-way valve is switched to a position where only the circuit is circulated.   The valve control device emits the exhaust gas when the rotation speed of the internal combustion engine is in a low and medium speed rotation range and the load torque is in a low torque range, or when the load torque is in a high speed rotation range and in a low and medium torque range. The warm-up device for an internal combustion engine according to claim 1, further comprising a first switching control unit that switches the three-way valve at a position that circulates only in the exhaust gas jacket.   The valve control device includes the three-way valve at a position where exhaust gas is circulated through the exhaust gas jacket and the EGR circuit when the rotational speed of the internal combustion engine is in a low / medium speed rotational speed region and the load torque is in a medium load torque region. The warm-up device for an internal combustion engine according to claim 1 or 2, further comprising a second switching control unit for switching.   The valve control device switches the three-way valve to a position where the exhaust gas flows only to the EGR circuit when the rotation speed of the internal combustion engine is in a low / medium rotation speed region and the load torque is in a high load torque region. The warm-up device for an internal combustion engine according to any one of claims 1 to 3, further comprising a control unit.   The valve control device switches the three-way valve to a position where the exhaust gas is blocked from flowing together with the exhaust gas jacket and the EGR circuit when the rotational speed of the internal combustion engine is in a high rotational speed region and the load torque is in a high load torque region. The warm-up device for an internal combustion engine according to any one of claims 1 to 4, further comprising a fourth switching control unit.   The warm-up device for an internal combustion engine according to claim 2 or 3, wherein when the temperature of the engine oil rises above a threshold value, the flow of the exhaust gas to the exhaust gas jacket is interrupted.

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