Engine system control device

Abstract

To provide an engine system control device suppressing piston-striking sound from cold start to warm-up completion of an engine.SOLUTION: An engine system control device includes: an engine loaded on a vehicle; an oil heater heating engine oil; an outdoor air temperature sensor detecting an outdoor air temperature; an oil temperature sensor detecting an oil temperature; and a water temperature sensor detecting a cooling water temperature. The engine system control device further includes: an electronic key determination part determining whether or not an electronic key of the vehicle exists around the vehicle before start of the engine; a cold state determination part determining whether or not the engine is in a cold state on the basis of an outdoor air temperature when the determination is affirmative by the electronic key determination part; a heater control part driving an oil heater when the determination is affirmative by the cold state determination part; an oil temperature determination part determining whether or not the oil temperature heated by the oil heater is higher than the cooling water temperature; and a start control part starting the engine when the determination is affirmative by the oil temperature determination part.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a control device for an engine system.

Background Art

[0002] In an engine, cooling water for cooling the engine and engine oil for lubricating the engine circulate (see, 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 starts cold, the temperature of the cooling water and the engine oil gradually rises. Here, the specific heat of the cooling water is smaller than that of the engine oil. Therefore, until the engine warm-up is completed, as the cooling water and the engine oil increase in temperature, the temperature difference between the two expands. As a result, there is a risk that the knocking sound of the piston increases.

[0005] Therefore, an object of the present invention is to provide a control device for an engine system that suppresses an increase in the knocking sound of the piston from cold start to completion of warm-up of the engine.

Means for Solving the Problems

[0006] The above object can be achieved by a control device for an engine system including an engine mounted on a vehicle, an oil heater for heating engine oil, an outside air temperature sensor for detecting the outside air temperature, an oil temperature sensor for detecting the temperature of the engine oil, and a water temperature sensor for detecting the temperature of the cooling water of the engine. The control device includes an electronic key determination unit that determines whether an electronic key of the vehicle is present around the vehicle before starting the engine, a cold determination unit that determines whether the engine is in a cold state based on the outside air temperature when an affirmative determination is made by the electronic key determination unit, a heater control unit that drives the oil heater when an affirmative determination is made by the cold determination unit, an oil temperature determination unit that determines whether the temperature of the engine oil heated by the oil heater is higher than the temperature of the cooling water, and a start control unit that starts the engine when an affirmative determination is made by the oil temperature determination unit.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a control device for an engine system that suppresses an increase in the knocking sound of a piston from cold start to warm-up completion of the engine.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] [Schematic Configuration of Engine System] FIG. 1 is a schematic configuration diagram of an engine system 1. The engine system 1 includes an engine 10, a main ECU (Electronic Control Unit) 50 that controls the engine 10, and an authentication ECU 51. The engine system 1 is mounted on a vehicle. The vehicle may be an engine vehicle or a hybrid vehicle equipped with a motor as a driving power source.

[0010] Inside the engine 10, an oil circulation path through which engine oil used for lubricating the engine 10 circulates is formed. The oil circulation path is provided with an oil pump 11, an oil strainer 14, an oil filter 15, and an OCV (Oil Control Valve) 18. The oil pump 11 sucks and discharges engine oil from an oil pan 13 of the engine 10. The oil pump 11 is a mechanical pump that operates in response to the rotation of a crankshaft 12, that is, the rotation of the engine 10. The oil strainer 14 is a filter that filters out relatively large foreign matters contained in the engine oil sucked by the oil pump 11. The oil filter 15 is a filter that filters out fine foreign matters contained in the engine oil discharged by the oil pump 11. The OCV 18 opens and closes under the control of the main ECU 50. By opening and closing the OCV 18, the discharge amount of the engine oil from the oil pump 11 is changed.

[0011] The engine oil discharged by the oil pump 11 is sent to a main gallery 16 after passing through the oil filter 15. Engine oil is distributively supplied from the main gallery 16 to each lubricating part 17 of the engine 10. The engine oil used for lubrication is recovered in the oil pan 13. The oil pan 13 is provided with an oil heater 19 that heats the resident engine oil. The oil heater 19 is, for example, a heating wire stretched around the inner bottom surface of the oil pan 13.

[0012] A cooling water circulation path for cooling the engine 10 is provided. In the cooling water circulation path, the engine 10, the multi-functional valve 21, the heater core 22, the throttle valve body (T / B) 23, the radiator 24, the inlet 25, and the electric water pump 26 are arranged. Specifically, the heater core 22 for heating the passenger compartment is arranged on the path 32 communicating the multi-functional valve 21 and the inlet 25. The throttle valve body 23 is arranged on the path 33 communicating the multi-functional valve 21 and the path 32. The radiator 24 is arranged on the path 34 communicating the multi-functional valve 21 and the inlet 25.

[0013] When the engine 10 is cold-started, the multi-functional valve 21 closes the paths 32 to 34 and the electric water pump 26 is maintained in a stopped state. Thereby, the warm-up of the engine 10 is promoted. After the warm-up is completed, the multi-functional valve 21 opens the paths 32 to 34 and the electric water pump 26 is driven, so that the cooling water discharged from the engine 10 flows back into the engine 10 again through the paths 32 to 34. It should be noted that when the temperature of the cooling water becomes equal to or higher than a predetermined warm-up temperature, it is determined that the warm-up of the engine 10 is completed.

[0014] The main ECU 50 and the authentication ECU 51 are each configured around a computer including volatile and non-volatile memories such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The main ECU 50 realizes various control processes related to the engine 10 by executing a program installed in the memory on the CPU. Although it will be described in detail later, various sensors are connected to the main ECU 50. The authentication ECU 51 detects the electronic key 60 which will be described in detail later. The main ECU 50 and the authentication ECU 51 are an example of a control device for the engine system, and functionally realize an electronic key determination unit, a cold determination unit, a heater control unit, an oil temperature determination unit, and a start control unit which will be described in detail later.

[0015] The main ECU 50 is electrically connected to an ignition switch 41, an air flow meter 42, an outside air temperature sensor 43, a water temperature sensor 44, and an oil temperature sensor 45. The ignition switch 41 detects the on / off state of the ignition. The air flow meter 42 detects the intake air amount. The outside air temperature sensor 43 detects the outside air temperature. The water temperature sensor 44 detects the temperature of the cooling water (hereinafter referred to as the water temperature) that cools the engine 10. The oil temperature sensor 45 detects the temperature of the engine oil (hereinafter referred to as the oil temperature).

[0016] The main ECU 50 calculates the engine load ratio based on the engine speed and the intake air amount, and controls the fuel injection amount, the intake air amount, and the ignition timing so that the engine speed and the load ratio respectively become the target engine speed and the target load ratio. Further, the main ECU 50 controls the multi-functional valve 21 and the electric water pump 26 based on the detection value of the water temperature sensor 44.

[0017] The authentication ECU 51 is communicably connected to the main ECU 50. The authentication ECU 51 transmits a request signal to the periphery of the vehicle and the passenger compartment in which the engine system 1 is mounted, and receives and collates the ID code transmitted from the electronic key 60 in response to the reception of the request signal. In this way, the authentication ECU 51 detects the electronic key 60.

[0018] Next, the knocking sound of the piston during cold start of the engine 10 will be described. FIG. 2A is a timing chart showing the transition of the water temperature and the oil temperature from cold start to warm-up completion of the engine 10 in the comparative example. In the cold state, both the water temperature and the oil temperature are low. When the engine 10 starts in this state (time t1), the water temperature and the oil temperature gradually rise. Here, the specific heat of the cooling water is smaller than the specific heat of the engine oil. Therefore, the water temperature rises earlier than the oil temperature. When the water temperature rises to a predetermined temperature and the warm-up of the engine 10 is completed (time t2). After that, the oil temperature also becomes constant at the predetermined temperature (time t3).

[0019] As shown in FIG. 2A, there is a region where the temperature difference between the coolant temperature and the engine oil temperature expands from when the engine 10 is cold-started until warm-up is completed. When the coolant temperature is higher than the engine oil temperature and the temperature difference is large in this way, there is a risk that the knocking sound of the piston will increase. The cylinder bore that houses the piston is cooled by the coolant. For this reason, as the coolant temperature rises, the inner diameter of the cylinder bore expands. On the other hand, the piston is lubricated by the engine oil. For this reason, the expansion rate of the outer diameter of the piston is smaller than the expansion rate of the inner diameter of the cylinder bore. As a result, the clearance between the outer diameter of the piston and the inner diameter of the cylinder bore expands. When the clearance expands, the behavior of the piston becomes unstable when the piston reciprocates in the cylinder bore, and the collision sound of the piston against the cylinder bore increases.

[0020] FIG. 2B is a timing chart showing the changes in the coolant temperature and the engine oil temperature from when the engine 10 is cold-started until warm-up is completed in this embodiment. When the authentication ECU 51 detects the electronic key 60, the main ECU 50 drives the oil heater 19 (time t0). As a result, the engine oil temperature gradually rises. After the engine oil temperature becomes higher than the coolant temperature by a predetermined threshold value or more, the engine 10 starts (time t1). Note that the oil heater 19 stops when the engine 10 starts. After that, warm-up of the engine 10 is completed (time t2), and the engine oil temperature also becomes constant at a predetermined temperature (time t3).

[0021] As described above, in this embodiment, the engine oil is preheated by the oil heater 19 before the engine 10 starts. As a result, the temperature difference between the engine oil temperature and the coolant temperature from cold-start to warm-up completion is reduced. Thereby, the increase in the piston knocking sound described above is suppressed.

[0022] [Engine Start Control] Next, the engine start control will be described. FIG. 3 is a flowchart showing an example of the engine start control. The authentication ECU 51 determines whether or not the electronic key 60 has been detected (step S1). If the result in step S1 is No, this control ends. Step S1 is an example of the process executed by the electronic key detection unit.

[0023] If the answer is Yes in step S1, the main ECU 50 acquires the outside air temperature, the oil temperature, and the water temperature (step S2). Next, the main ECU 50 determines whether the engine 10 is in a cold state based on the outside air temperature (step S3). For example, if the outside air temperature is 0 degrees Celsius or lower, it is determined that the engine is in a cold state. If the answer is No in step S3, this control ends. Step S3 is an example of the process executed by the cold determination unit.

[0024] If the answer is Yes in step S3, the main ECU 50 drives the oil heater 19 (step S4). Thereby, heating of the engine oil is started. Step S4 is an example of the process executed by the heater control unit.

[0025] Next, the main ECU 50 determines whether the temperature difference obtained by subtracting the water temperature from the oil temperature is equal to or greater than a threshold value (step S5). The threshold value is set to a temperature difference sufficient to suppress the increase in the piston knocking sound described above. If the answer is No in step S5, step S4 is continued. Step S5 is an example of the process executed by the oil temperature determination unit.

[0026] If the answer is Yes in step S5, the main ECU 50 stops the oil heater 19 (step S6) and starts the engine 10 (step S7). Thereby, an increase in the piston knocking sound from the cold start to the warm-up completion of the engine 10 is suppressed.

[0027] Note that in step S5, it may be determined whether the oil temperature is higher than the water temperature. In a cold state, the water temperature and the oil temperature are approximately the same temperature. If the oil temperature is higher than the water temperature by the oil heater 19 before starting the engine 10, an increase in the temperature difference between the oil temperature and the water temperature until the warm-up is completed is suppressed.

[0028] As described above, the embodiments of the present invention have been described in detail. However, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of reference numerals

[0029] 1 Engine system 10 Engine 19 Oil heater 43 Outside air temperature sensor 44 Water temperature sensor 45 Oil temperature sensor 50 Main ECU (control device for engine system, cold determination unit, heater control unit, oil temperature determination unit, start control unit) 51 Authentication ECU (control device for engine system, electronic key determination unit) 60 Electronic key

Claims

【Claim 1】 A control device for an engine system including an engine mounted on a vehicle, an oil heater for heating engine oil, an outside air temperature sensor for detecting the outside air temperature, an oil temperature sensor for detecting the temperature of the engine oil, and a water temperature sensor for detecting the temperature of the cooling water of the engine, an electronic key determination unit that determines whether an electronic key of the vehicle is present around the vehicle before starting the engine, a cold determination unit that determines whether the engine is in a cold state based on the outside air temperature when an affirmative determination is made by the electronic key determination unit, a heater control unit that drives the oil heater when an affirmative determination is made by the cold determination unit, an oil temperature determination unit that determines whether the temperature of the engine oil heated by the oil heater is higher than the temperature of the cooling water, and a start control unit that starts the engine when an affirmative determination is made by the oil temperature determination unit. A control device for an engine system.

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