Engine oil heating device

Abstract

To efficiently heat engine oil.SOLUTION: An engine oil heating device includes: a branch flow passage branched from an EGR flow passage having an EGR valve and connected to an exhaust flow passage; a heat exchanger provided in the branch flow passage and exchanging heat between engine oil and exhaust gas; a valve provided in the branch flow passage; and a control device having one or a plurality of processors and one or a plurality of memories connected to the processors. The processor executes processing including adjustment of an opening of the valve on the basis of a temperature of the engine oil and an opening of the EGR valve.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an engine oil heating device for heating engine oil.

Background Art

[0002] A lubrication system that circulates engine oil for lubricating and cooling sliding parts such as clutches and transmission devices is provided in a vehicle (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the engine oil is at a low temperature, its viscosity increases. Therefore, when the engine oil is at a low temperature, there is a problem that the friction at the sliding part increases and the fuel consumption deteriorates.

[0005] An object of the present invention is to efficiently heat engine oil.

Means for Solving the Problems

[0006] To solve the above problems, an engine oil heating device according to an embodiment of the present invention includes a branch flow path branched from an EGR flow path provided with an EGR valve and connected to an exhaust flow path, a heat exchanger provided in the branch flow path for heat-exchanging engine oil and exhaust gas, a valve provided in the branch flow path, a control device having one or more processors and one or more memories connected to the processors, and is provided with The processor executes a process including adjusting the opening degree of the valve based on the temperature of the engine oil and the opening degree of the EGR valve.

Advantages of the Invention

[0007] According to the present invention, it becomes possible to efficiently heat the engine oil.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present invention are not shown.

[0010] FIG. 1 is a schematic diagram showing the configuration of a vehicle 100 according to an embodiment of the present invention. In FIG. 1, the dashed arrows indicate the flow of signals.

[0011] As shown in FIG. 1, the vehicle 100 includes an engine 110, an intake passage 120, an exhaust passage 130, a catalyst 140, an EGR device 150, and an engine oil heating device 160.

[0012] The vehicle 100 is, for example, a hybrid vehicle having an engine 110 and a motor as drive sources. The engine 110 is a gasoline engine or a diesel engine. However, the vehicle according to the present embodiment is not limited to this example and may include only the engine 110.

[0013] An intake manifold is communicated with the intake port of the engine 110. An intake passage (intake pipe) 120 is communicated with the collecting portion of the intake manifold.

[0014] An exhaust manifold is communicated with the exhaust port of the engine 110. An exhaust passage (exhaust pipe) 130 is communicated with the collecting portion of the exhaust manifold. A catalyst 140 is provided in the exhaust passage 130.

[0015] The catalyst 140 oxidizes and reduces hydrocarbons (HC), carbon monoxide (CO), and NOx (nitrogen oxides) contained in the exhaust gas discharged from the engine 110 to purify the exhaust gas. The catalyst 140 is, for example, a three-way catalyst (TWC). The catalyst 140 includes, for example, platinum (Pt), palladium (Pd), rhodium (Rh), and an OSC material (e.g., ceria).

[0016] The EGR (Exhaust Gas Recirculation) device 150 recirculates a part of the exhaust gas into the intake passage 120 as EGR gas. The EGR device 150 includes an EGR passage 152, an EGR cooler 154, and an EGR valve 156.

[0017] The EGR passage 152 branches from the upstream side of the catalyst 140 in the exhaust passage 130 and is connected to the intake passage 120. In other words, the EGR passage 152 is a passage that communicates between the engine 110 and the catalyst 140 in the exhaust passage 130 and the intake passage 120.

[0018] The EGR cooler 154 is provided in the EGR passage 152. The EGR cooler 154 cools the EGR gas by exchanging heat between the EGR gas passing through the EGR passage 152 and the coolant (cooling water).

[0019] FIG. 2 is a diagram for explaining a coolant circulation mechanism 170 of a vehicle 100 according to an embodiment of the present invention. In FIG. 2, solid arrows indicate the flow of the coolant.

[0020] As shown in FIG. 2, the coolant circulation mechanism 170 provided in the vehicle 100 includes a radiator 172 and a water pump 174.

[0021] The radiator 172 exchanges heat between the coolant and the outside air to cool the coolant. The suction side of the water pump 174 is connected to the radiator 172. The discharge side of the water pump 174 is connected to, for example, a cylinder head 112 and a cylinder block 114 that constitute the engine 110, and the EGR cooler 154. The water pump 174 supplies the coolant to the cylinder head 112, the cylinder block 114, and the EGR cooler 154.

[0022] The cylinder head 112 and the cylinder block 114 are cooled by the coolant supplied by the water pump 174. The EGR cooler 154 exchanges heat between the coolant supplied by the water pump 174 and the EGR gas. Thereby, the EGR gas is cooled.

[0023] The coolant that has passed through the cylinder head 112, the cylinder block 114, and the EGR cooler 154 is returned to the radiator 172.

[0024] Returning to FIG. 1 for explanation, the EGR valve 156 is provided on the downstream side of the EGR cooler 154 in the EGR flow path 152 in the flow direction of the EGR gas (exhaust gas). The EGR valve 156 is provided between the EGR cooler 154 and the connection point of the intake air flow path 120 in the EGR flow path 152. That is, the EGR gas flows through the EGR flow path 152 in the order of the EGR cooler 154 and the EGR valve 156. The EGR valve 156 adjusts the opening degree of the EGR flow path 152. The EGR valve 156 is driven by, for example, a stepping motor.

[0025] The engine oil heating device 160 heats the engine oil. The engine oil heating device 160 includes a branch flow path 210, a heat exchanger 220, an oil temperature sensor 230, a valve 240, and a control device 250.

[0026] The branch flow path 210 branches from the downstream of the EGR cooler 154 in the EGR flow path 152 and is connected to the exhaust flow path 130. In the present embodiment, the branch flow path 210 branches from between the EGR cooler 154 and the EGR valve 156 in the EGR flow path 152. Further, the branch flow path 210 is connected between the connection point of the EGR flow path 152 and the catalyst 140 in the exhaust flow path 130. In other words, the branch flow path 210 is a flow path that communicates the EGR flow path 152 and the exhaust flow path 130.

[0027] The heat exchanger 220 is provided in the branch flow path 210. The heat exchanger 220 heats the engine oil by heat-exchanging the engine oil and the exhaust gas (EGR gas).

[0028] FIG. 3 is a diagram for explaining the engine oil circulation mechanism 180 of the vehicle 100 according to an embodiment of the present invention. In FIG. 3, the solid arrows indicate the flow of the engine oil.

[0029] As shown in FIG. 3, the engine oil circulation mechanism 180 provided in the vehicle 100 includes an oil pan 182, an oil pump 184, and an oil filter 186.

[0030] The oil pan 182 is provided, for example, below the cylinder block 114 of the engine 110. The oil pan 182 stores engine oil. The suction side of the oil pump 184 is connected to the oil pan 182. The discharge side of the oil pump 184 is connected to the heat exchanger 220. The oil pump 184 supplies the engine oil stored in the oil pan 182 to the heat exchanger 220.

[0031] As described above, the heat exchanger 220 exchanges heat between the engine oil and the exhaust gas. Thereby, the engine oil is heated and the exhaust gas is cooled. The engine oil heated by the heat exchanger 220 is supplied to the oil filter 186.

[0032] The oil filter 186 removes impurities such as sludge, wear powder, and dust from the engine oil. The engine oil from which impurities have been removed by the oil filter 186 passes through the heat exchanger 220 again and is supplied to the sliding part SP. The sliding part SP is a clutch, a transmission, or the like.

[0033] The engine oil lubricates and cools the sliding part SP. The engine oil that has passed through the sliding part SP is returned to the oil pan 182.

[0034] The oil temperature sensor 230 detects the temperature of the engine oil. In the present embodiment, the oil temperature sensor 230 detects the temperature of the engine oil flowing between the heat exchanger 220 and the sliding part SP. That is, the oil temperature sensor 230 detects the temperature of the engine oil supplied from the heat exchanger 220 to the sliding part SP.

[0035] Returning to FIG. 1 for explanation, the valve 240 is provided on the upstream side in the flow direction of the EGR gas (exhaust gas) of the heat exchanger 220 in the branch flow path 210. The valve 240 is provided between the branch point from the EGR flow path 152 and the heat exchanger 220 in the branch flow path 210. That is, the EGR gas flows through the branch flow path 210 in the order of the valve 240 and the heat exchanger 220. The valve 240 opens and closes the branch flow path 210. The branch flow path 210 is, for example, a solenoid valve.

[0036] The control device 250 includes one or more processors 252 and one or more memories 254 connected to the processor 252. The processor 252 includes, for example, a CPU (Central Processing Unit). The memory 254 includes, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM is a storage element that stores programs and arithmetic parameters used by the CPU. The RAM is a storage element that temporarily stores data such as variables and parameters used in the processes executed by the CPU.

[0037] The control device 250 communicates with each device provided in the vehicle 100 (for example, the engine 110, the oil temperature sensor 230, etc.). The communication between the control device 250 and each device is realized by using, for example, CAN (Controller Area Network) communication.

[0038] FIG. 4 is a block diagram showing an example of the functional configuration of the control device 250 according to an embodiment of the present invention. For example, as shown in FIG. 4, the control device 250 includes a valve control unit 290. Various processes including the processes described below performed by the valve control unit 290 can be executed by the processor 252. Specifically, by the processor 252 executing the program stored in the memory 254, various processes are executed.

[0039] The valve control unit 290 adjusts the opening degree of the valve 240 based on the temperature of the engine oil detected by the oil temperature sensor 230 and the opening degree of the EGR valve 156. Specific processes by the valve control unit 290 will be described in detail later.

[0040] [Engine Oil Heating Method] FIG. 5 is a flowchart showing the flow of the process of the engine oil heating method according to an embodiment of the present invention.

[0041] As shown in FIG. 5, the engine oil heating method includes a temperature determination step S110, a closing step S120, an opening degree determination step S130, and an opening step S140. Hereinafter, each step will be described in detail.

[0042] [Temperature determination step S110] The valve control unit 290 determines whether or not the detected value T of the oil temperature sensor 230 is equal to or higher than the target temperature Ttg. The target temperature Ttg is a predetermined temperature, for example, equal to or higher than 80°C and equal to or lower than 90°C.

[0043] As a result, when it is determined that the detected value T of the oil temperature sensor 230 is equal to or higher than the target temperature Ttg (YES in S110), the valve control unit 290 transfers the process to the closing step S120. On the other hand, when it is determined that the detected value T of the oil temperature sensor 230 is not equal to or higher than the target temperature Ttg, that is, less than the target temperature Ttg (NO in S110), the valve control unit 290 transfers the process to the opening degree determination step S130. When the detected value T of the oil temperature sensor 230 is less than the target temperature Ttg, for example, it is when the temperature of the engine 110 is relatively low, such as at the start of the engine 110 or during low load.

[0044] [Closing step S120] The valve control unit 290 sets the valve 240 to the closed state.

[0045] [Opening degree determination step S130] The valve control unit 290 determines whether or not the opening degree V of the EGR valve 156 is less than the opening degree threshold value Vth. The opening degree threshold value Vth (predetermined opening degree) is, for example, the minimum opening degree of the EGR valve 156. The minimum opening degree of the EGR valve 156 is determined in advance by regulations. For example, in the case of the EGR valve 156 that is fully closed when the number of steps of the stepping motor is 0 steps and fully open when the number of steps is 60 steps, the minimum opening degree of the EGR valve 156 is, for example, the opening degree when the number of steps of the stepping motor is 3 steps.

[0046] As a result, when it is determined that the opening degree V of the EGR valve 156 is less than the opening degree threshold value Vth (YES in S130), the valve control unit 290 transfers the process to the opening process S140. On the other hand, when it is determined that the opening degree V of the EGR valve 156 is not less than the opening degree threshold value Vth, that is, the opening degree V is greater than or equal to the opening degree threshold value Vth (NO in S130), the valve control unit 290 transfers the process to the closing process S120.

[0047] [Opening process S140] The valve control unit 290 sets the valve 240 to the open state.

[0048] As described above, the engine oil heating device 160 according to the present embodiment heats the engine oil with the heat of the EGR gas (exhaust gas). Thereby, the engine oil heating device 160 does not need to separately secure a dedicated heat source for heating the engine oil. Therefore, the engine oil heating device 160 can efficiently heat the engine oil.

[0049] In particular, when the vehicle 100 is a hybrid vehicle, compared with the case where only the engine 110 is used as a power source, the period of low load and low rotation operation is long, and the frequency of starting and stopping the engine 110 is high. For this reason, when the vehicle 100 is a hybrid vehicle, the temperature of the engine oil tends to decrease. Therefore, by providing the vehicle 100 with the engine oil heating device 160, the engine oil can be efficiently heated, and the viscosity of the engine oil can be reduced. For this reason, the vehicle 100 provided with the engine oil heating device 160 can reduce the friction at the sliding portion SP and improve the fuel efficiency.

[0050] Further, as described above, when the engine oil heating device 160 hardly returns the EGR gas to the intake air passage 120, the engine oil is heated by the heat of the EGR gas. That is, when the engine oil heating device 160 actively returns the EGR gas to the intake air passage 120, the supply of the EGR gas to the heat exchanger 220 is stopped. Thereby, the engine oil heating device 160 can avoid a situation in which the return of the EGR gas to the intake air passage 120 is inhibited. Therefore, the engine oil heating device 160 can maintain an improvement in fuel efficiency based on the return of the EGR gas to the intake air passage 120.

[0051] Note that it is also conceivable that the EGR cooler 154 exchanges heat between the engine oil and the EGR gas instead of the coolant. However, in this comparative example, the engine oil can be heated only when the EGR gas is returned to the intake air passage 120. For this reason, in the comparative example, when the EGR gas is returned to the intake air passage 120 to heat the engine oil, problems may occur. For example, when the engine 110 is at a low load or starting, since the engine oil is at a low temperature, heating of the engine oil is desired. However, when the EGR gas is returned to the intake air passage 120 during low load or starting of the engine 110, combustion may become slow and the engine 110 may misfire.

[0052] On the other hand, the vehicle 100 according to the present embodiment includes an engine oil heating device 160 in addition to the EGR device 150, and performs active return of the EGR gas to the intake air passage 120 and heating of the engine oil at different timings. Thereby, the engine oil heating device 160 can heat the engine oil without actively returning the EGR gas during low load or starting of the engine 110 when the engine oil is at a low temperature. Therefore, the engine oil heating device 160 can heat the engine oil while preventing misfire of the engine 110 during low load or starting of the engine 110.

[0053] Also, as described above, the engine oil heating device 160 heats the engine oil with the EGR gas (for example, about 120°C) cooled by the EGR cooler 154. Thereby, the engine oil heating device 160 can control the temperature of the engine oil with high precision as compared with the case where the engine oil is heated by the high-temperature (for example, about 500°C) EGR gas before being cooled by the EGR cooler 154.

[0054] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. Needless to say, the present invention is not limited to such embodiments. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention.

[0055] Also, in the above embodiment, the case where the branch flow path 210 branches from the downstream of the EGR cooler 154 in the EGR flow path 152 has been described as an example. However, as long as the branch flow path 210 branches from the EGR flow path 152, there is no limitation on the branching location. For example, the branch flow path 210 may branch from the upstream of the EGR cooler 154 in the EGR flow path 152.

[0056] Also, in the above embodiment, the case where the valve 240 is provided upstream of the heat exchanger 220 in the branch flow path 210 has been described as an example. Thereby, the temperature of the engine oil can be controlled with high precision. However, as long as the valve 240 is provided in the branch flow path 210, there is no limitation on the installation location. For example, the valve 240 may be provided downstream of the heat exchanger 220 in the branch flow path 210. When the valve 240 is provided downstream of the heat exchanger 220, the engine oil can be preheated in the heat exchanger 220 even when the valve 240 is closed.

[0057] Also, in the above-described embodiment, the case where the valve 240 is an on-off valve has been taken as an example. However, the valve 240 may be a flow rate adjustment valve that adjusts the opening degree of the branch flow path 210. When the valve 240 is a flow rate adjustment valve, the temperature of the engine oil can be controlled with high precision.

Explanation of Reference Numerals

[0058] 152 EGR flow path 154 EGR cooler 156 EGR valve 160 Engine oil heating device 210 Branch flow path 220 Heat exchanger 240 Valve 250 Control device 252 Processor 254 Memory

Claims

1. a branch flow path branched from an EGR flow path provided with an EGR valve and connected to an exhaust flow path; a heat exchanger provided in the branch flow path for heat-exchanging engine oil and exhaust gas; a valve provided in the branch flow path; a control device having one or more processors and one or more memories connected to the processors; comprising; the processor; An engine oil heating device that executes a process including adjusting an opening degree of the valve based on a temperature of the engine oil and an opening degree of the EGR valve.

2. the processor; The engine oil heating device according to claim 1, which executes a process including opening the valve when the temperature of the engine oil is less than a target temperature and the opening degree of the EGR valve is less than a predetermined opening degree.

3. an EGR cooler is provided in the EGR flow path; The branch flow path branches from downstream of the EGR cooler in the EGR flow path. The engine oil heating device according to claim 1 or 2.

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