JP2020051387A - Control device for cooling water system for internal combustion engine - Google Patents

Abstract

To improve fuel efficiency of a vehicle at low cost by using a simple configuration.SOLUTION: In a cooling water system for a water-cooled type internal combustion engine mounted to a vehicle, a control device is configured to control whether or not cooling water is caused to flow in a heater core for exchanging heat with air in a cabin and a heat exchanger for exchanging heat with fluid in accordance with a current cooling water temperature, an outside air temperature and a temperature of the fluid used for a transmission of a vehicle drive system. Due to the fine control in accordance with the current cooling water temperature, the outside air temperature and the fluid temperature, fuel efficiency of the vehicle can be improved.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cooling water system for a water-cooled internal combustion engine mounted on a vehicle.

  It is customary to use the cooling water of the internal combustion engine as a heat source for air conditioning in a vehicle cabin of a vehicle equipped with the internal combustion engine, particularly for heating. That is, heated water is introduced into the heater core from the internal combustion engine, and heat exchange is performed between the heater core and air, thereby supplying warm air into the vehicle interior.

  In addition, in recent vehicles, a heat exchanger that exchanges heat with a fluid (so-called ATF or CVTF) used for a transmission is provided in a cooling water system of an internal combustion engine (for example, for example). And the following patent documents). This heat exchanger serves to raise the temperature of the fluid at an early stage at the time of a cold start and to reduce mechanical loss (including friction loss) in the transmission.

JP-A-2002-340161

  On the flow path of the cooling water flowing through the heat exchanger for fluid, a wax pellet thermostat, a bellows thermostat, a bimetal thermostat, or a shape is used in order to switch whether or not the cooling water flows into the heat exchanger. A memory alloy thermostat is installed. This type of thermostat has a large number of parts, but has a simple function. If the cooling water temperature becomes higher than a set value, the thermostat is not opened or only closed, and is not cost-effective.

  Also, many existing systems do not control the flow of cooling water from the internal combustion engine to the heater core at all, and the cooling water continues to circulate through the heater core as long as the cooling water pump operates. At the time of cold start, it is desirable to warm up the internal combustion engine as soon as possible to reduce the mechanical loss in the internal combustion engine. However, since the heat is taken from the heater core, the warming-up is delayed, and there is a disadvantage in fuel efficiency performance. Invite.

  An object of the present invention is to improve the fuel efficiency of a vehicle at a low cost with a simple configuration.

  According to the present invention, in the cooling water system of the water-cooled internal combustion engine mounted on the vehicle, the current of the cooling water, the outside air temperature, and the temperature of the fluid used for the transmission of the drive system of the vehicle are adjusted according to the temperature in the vehicle interior. A control device is configured to control whether or not the coolant flows through a heater core that exchanges heat between the heat exchanger and the heat exchanger that exchanges heat with the fluid.

  ADVANTAGE OF THE INVENTION According to this invention, the improvement of the fuel consumption performance of a vehicle can be implement | achieved at low cost with a simple structure.

FIG. 1 is a diagram illustrating a configuration of an internal combustion engine and a control device mounted on a vehicle according to an embodiment of the present invention. The figure which shows the structure of the cooling water system of the internal combustion engine in the embodiment. The figure explaining the content of the control which the control device of the embodiment performs.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of a water-cooled internal combustion engine mounted on a vehicle. The illustrated internal combustion engine is a spark ignition type four-stroke gasoline engine, and includes a plurality of cylinders 1 (one of which is shown in FIG. 1). An injector 11 for injecting fuel is provided near an intake port of each cylinder 1. An ignition plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 is adapted to generate a spark discharge between the center electrode and the ground electrode by receiving the induction voltage generated by the ignition coil.

  An intake passage 3 for supplying intake air takes in air from the outside and guides it to an intake port of each cylinder 1. On the intake passage 3, an air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from upstream.

  An exhaust passage 4 for discharging exhaust gas guides exhaust gas generated as a result of burning fuel in the cylinder 1 from the exhaust port of each cylinder 1 to the outside. On the exhaust passage 4, an exhaust manifold 42 and a three-way catalyst 41 for purifying exhaust gas are arranged.

  The external EGR (Exhaust Gas Recirculation) device 2 realizes a so-called high-pressure loop EGR, and includes an EGR passage 21 communicating between an upstream side of the catalyst 41 in the exhaust passage 4 and a downstream side of the throttle valve 32 in the intake passage 3. , An EGR cooler 22 provided on the EGR passage 21, and an EGR valve 23 that opens and closes the EGR passage 21 and controls a flow rate of EGR gas flowing through the EGR passage 21. The inlet of the EGR passage 21 is connected to the exhaust manifold 42 in the exhaust passage 4 or a predetermined location downstream thereof. The outlet of the EGR passage 21 is connected to a predetermined portion of the intake passage 3 downstream of the throttle valve 32, specifically, to a surge tank 33.

  A transmission is mounted on a drive system that connects the internal combustion engine, which is a drive source of the vehicle, to the axle and drive wheels of the vehicle. The transmission is, for example, a known torque converter and automatic transmission 6. The automatic transmission 6 may be a belt-type CVT (Continuously Variable Transmission), which is a type of a continuously variable transmission. In that case, a forward / reverse switching device using a planetary gear mechanism is interposed between the torque converter and the belt type CVT.

  A common transmission fluid (CVTF) is used for the torque converter, the forward / reverse switching device, and the belt type CVT. The fluid is responsible for transmission of driving force, supply of clutch engagement pressure, supply of belt clamping pressure, lubrication, and the like. The oil pump that sucks and discharges fluid is located between the torque converter and the forward / reverse switching device, and operates by receiving a driving force transmitted from a crankshaft that is an output shaft of the internal combustion engine.

  FIG. 2 shows a cooling water system of the internal combustion engine in the present embodiment. The cooling water pump 51 that sucks and discharges cooling water operates by receiving torque transmitted from the crankshaft of the internal combustion engine. Needless to say, an electric pump may be used as the cooling water pump 51. The cooling water discharged from the cooling water pump 51 first flows into the cylinder block 52 of the internal combustion engine, and then flows into the cylinder head 53. Then, the air is sent out from the cylinder head 53 toward the CVTF warmer 55, the heater core 54, the EGR cooler 22, the throttle body 320 including the throttle valve 32, the valve housing 230 including the EGR valve 23, and the radiator 56.

  The CVTF warmer 55 is a heat exchanger that performs heat exchange between cooling water of the internal combustion engine and fluid used for the torque converter and the automatic transmission 6. The CVTF warmer 55 quickly raises the temperature of the fluid at the time of a cold start and suppresses the temperature of the fluid from becoming excessively high, for example, 100 ° C. or more.

  The heater core 54 exchanges heat between the cooling water and the air in the vehicle compartment, and works for air conditioning in the vehicle compartment, particularly for heating.

  The EGR cooler 22 performs heat exchange between the cooling water and the EGR gas, and lowers the temperature of the EGR gas flowing into the intake passage 3.

  The purpose of supplying the cooling water to the throttle body 320 and the valve housing 230 is to raise the temperature of each of the valves 32 and 23 at an early stage during a cold start and to prevent the valves 32 and 23 from freezing.

  The cooling water flowing from the cylinder head 53 toward the CVTF warmer 55 and the heater core 54 initially flows through the same flow path, and thereafter branches off and flows into each of the CVTF warmer 55 and the heater core 54. In the present embodiment, an FSV (Flow Shut Valve or Flow Shutter Valve) for opening and closing the flow path is provided on a flow path where the cooling water flowing into the CVTF warmer 55 and the cooling water flowing into the heater core 54 join. 57 are installed. The FSV 57 is an on-off valve that opens and closes in response to the control signal m, or a flow control valve that changes the opening thereof, and is, for example, a solenoid valve. In the illustrated example, the FSV 57 is provided upstream of the CVTF warmer 55 and the heater core 54, that is, on a flow path where the cooling water flowing into the CVTF warmer 55 and the cooling water flowing into the heater core 54 join before branching. However, it goes without saying that the FSV 57 may be provided downstream of the CVTF warmer 55 and the heater core 54, that is, on the flow path where the cooling water passing through the CVTF warmer 55 and the cooling water passing through the heater core 54 rejoin.

  The cooling water flowing through the CVTF warmer 55 and the cooling water flowing through the heater core 54 join again and head toward the EGR cooler 22. Further, the cooling water flowing through the throttle body 320 and the valve housing 230 is added to the flow. The cooling water flowing through the EGR cooler 22 flows down to the cylinder block 52 and is sucked into the cooling water pump 51 again.

  The radiator 56 is a radiator that lowers the temperature of the cooling water by natural or forced air cooling. A thermostat 58 for opening and closing the cooling water return path is provided on the cooling water return path connecting the radiator 56 and the cylinder block 52. The thermostat 58 opens when the temperature of the cooling water becomes higher than a set value, and closes when the temperature is lower than the set value.

  An ECU (Electronic Control Unit) 0 as a control device in the present embodiment is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like. The ECU 0 may be a configuration in which a plurality of ECUs or controllers are communicably connected to each other via an electric communication line such as a CAN (Controller Area Network).

  The input interface of the ECU 0 includes a vehicle speed signal a output from a vehicle speed sensor for detecting the actual vehicle speed of the vehicle, a crank angle signal b output from a crank angle sensor for detecting the rotation angle of the crankshaft of the internal combustion engine and the engine speed. An accelerator opening signal c output from a sensor for detecting the amount of depression of an accelerator pedal or the opening of a throttle valve 32 as an accelerator opening (in other words, a required load factor for an internal combustion engine), and an outside air temperature sensor for detecting the temperature of outside air. , An intake air temperature / intake pressure signal e output from a temperature / pressure sensor for detecting the intake air temperature and intake pressure in the intake passage 3 (particularly, the surge tank 33), and an internal combustion engine temperature. Detects the cooling water temperature signal f output from the water temperature sensor that detects the suggested cooling water temperature, and detects the temperature of the transmission fluid That the liquid temperature fluid temperature signal g outputted from the sensor, a cam angle signal h or the like to be output from the cam angle sensor at a plurality of cam angle of the intake camshaft or an exhaust camshaft of the internal combustion engine is input.

  From the output interface of the ECU 0, an ignition signal i for the igniter of the ignition plug 12, a fuel injection signal j for the injector 11, an opening operation signal k for the throttle valve 32, and an opening operation for the EGR valve 23. An open / close control signal m and the like are output in response to the signal 1 and the FSV 57.

  The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates operation parameters, and controls the operation of the internal combustion engine. The ECU 0 acquires various information a, b, c, d, e, f, g, and h necessary for operation control of the internal combustion engine through an input interface, obtains the engine speed, and charges the cylinder 1. Estimate intake volume. The required fuel injection amount, fuel injection timing (including the number of times of fuel injection for one combustion), fuel injection pressure, ignition timing, required EGR rate (or EGR) Various operating parameters such as the amount of gas), whether or not to lock up the torque converter, the gear ratio of the automatic transmission, the opening and closing of the FSV 57 or its opening degree, are determined. The ECU 0 applies various control signals i, j, k, l, m corresponding to the operation parameters via an output interface.

  Thus, the ECU 0 determines whether or not to flow the cooling water through the heater core 54 and the CVTF warmer 55 according to the current cooling water temperature, the outside air temperature, and the temperature of the transmission fluid of the internal combustion engine, and opens and closes the FSV 57. .

  As described above, in the present embodiment, one FSV 57 that can be operated at any time is installed in the cooling water system of the internal combustion engine, and the FSV 57 causes the cooling water to flow into the heater core 54 and the cooling water to flow into the CVTF warmer 55. Can be controlled. Needless to say, when the FSV 57 is opened, the cooling water flows into the heater core 54 and the CVTF warmer 55, and when the FSV 57 is closed, the cooling water does not flow into the heater core 54 and the CVTF warmer 55.

  FIG. 3 shows an opening / closing pattern of the FSV 57 by the ECU 0. In the figure, the area indicated by adding a halftone dot is an area where the FSV 57 is closed, and the other area is an area where the FSV 57 is opened. In principle, the ECU 0 opens the FSV 57 and allows the coolant of the internal combustion engine to flow into the heater core 54 regardless of the coolant temperature or the fluid temperature in an environment where the outside air temperature is a low temperature less than β. This is to maintain the heating performance of the vehicle interior.

  When the cooling water temperature is higher than α, the FSV 57 is opened to flow the cooling water into the CVTF warmer 55. This is because the internal combustion engine has already been warmed up to a certain degree or more, and it is not necessary to close the FSV 57 to accelerate the temperature rise of the internal combustion engine, but rather to raise the temperature of the transmission fluid.

  When the fluid temperature exceeds γ and becomes excessively high, the FSV 57 is opened to allow the cooling water to flow into the CVTF warmer 55. This is to prevent the temperature of the transmission fluid from rising further, and to further promote the temperature drop of the fluid.

  When the outside air temperature is equal to or more than β, the fluid temperature is equal to or less than γ, and the cooling water temperature is lower than α, basically, the FSV 57 is closed to stop the flow of the cooling water into the heater core 54 and the CVTF warmer 55. Good. Typically, this corresponds to the time immediately after the cold start except in a cold environment. However, by closing the FSV 57, the heat is not deprived to the heater core 54 and the CVTF warmer 55, and the internal combustion engine Warm-up can be accelerated.

  However, in a situation where the cooling water temperature is equal to or less than α and the fluid temperature is equal to or less than γ, and the temperature of the cooling water and the temperature of the transmission fluid are low, closing the FSV 57 increases the fluid temperature instead of increasing the cooling water temperature. However, there is a trade-off in that opening the FSV 57 removes heat from the cooling water as much as the fluid temperature rises. It cannot be uniquely determined whether to give priority to an increase in the cooling water temperature or an increase in the fluid temperature.

  As an example, in a situation where the cooling water temperature is equal to or lower than α and the fluid temperature is equal to or lower than γ (assuming that the outside air temperature is equal to or higher than β), if the cooling water temperature is lower than a predetermined temperature, priority is given to warming up the internal combustion engine. While the FSV 57 is closed, if the coolant temperature is higher than that, the FSV 57 is opened on condition that the fluid temperature is lower than the threshold value, and the threshold value is raised as the current coolant temperature is higher ( The lower the cooling water temperature, the lower the cooling water temperature).

  In the present embodiment, in the cooling water system of the water-cooled internal combustion engine mounted on the vehicle, the cooling water flowing through the heater core 54 that exchanges heat with the air in the vehicle cabin and the transmission of the drive system of the vehicle are used. A single valve 57 that can be opened and closed arbitrarily irrespective of the current temperature of the cooling water is provided on a flow path through which the cooling water flowing through the heat exchanger 55 that performs heat exchange with the fluid is supplied. The valve 57 controls whether or not cooling water flows through the heater core 54 and the heat exchanger 55.

  The control device 0 according to the present embodiment determines whether or not to flow the cooling water through the heater core 54 and the heat exchanger 55 according to the current cooling water temperature, the outside air temperature, and the temperature of the fluid used for the transmission of the drive system of the vehicle. Control. According to the present embodiment, it is possible to improve the fuel efficiency of the vehicle with a simple configuration. Unlike the thermostat, the control valve 57 can be opened and closed flexibly, and it is possible to realize fine control according to the current cooling water temperature, outside air temperature and fluid temperature. Moreover, in the structure of the cooling water system according to the present embodiment, it is not necessary to increase the number of the control valves 57, and the cost does not increase.

  Note that the present invention is not limited to the embodiment described in detail above. First, the control valve FSV 57 is not limited to the electromagnetic solenoid valve. Any valve may be used as long as the control device ECU0 can open and close as needed, and a valve that opens and closes by supplying a hydraulic pressure through a hydraulic circuit may be employed.

  Further, in the above-described embodiment, one FSV 57 simultaneously controls whether the coolant flows through the heater core 54 and whether the coolant flows through the CVTF warmer 55 as the heat exchanger. On the other hand, the ECU 0 is provided in the flow path through which the cooling water flows through the heater core 54 and the flow path through which the cooling water flows through the CVTF warmer 55, which is different from the flow path, regardless of the current cooling water temperature. FSVs that can be arbitrarily opened and closed may be individually installed so that opening and closing of the former channel and opening and closing of the latter channel can be controlled independently.

  In this case, the cooling water does not flow into the heater core 54 and the CVTF warmer 55, the cooling water flows into the heater core 54 but does not flow into the CVTF warmer 55, and the cooling water flows into the CVTF warmer 55 but the heater core does not flow. Four states can be realized: a state in which the cooling water does not flow into the heater core 54 and a state in which the cooling water flows into the heater core 54 and the CVTF warmer 55.

  Then, the ECU 0 selects which of these states to take depending on the current cooling water temperature, the outside air temperature, and the temperature of the fluid used for the transmission of the drive system of the vehicle. For example, in an environment where the outside air temperature is a low temperature less than β, the cooling water flows into the heater core 54, but whether the cooling water flows into the CVTF warmer 55 can be made variable according to the cooling water temperature or the fluid temperature. it can. That is, when the cooling water temperature is higher than α or when the fluid temperature is higher than γ, the cooling water flows into the CVTF warmer 55; otherwise, the cooling water can be prevented from flowing into the CVTF warmer 55. .

  Alternatively, in a situation where the cooling water temperature or the fluid temperature immediately after the cold start is low, the cooling water may be caused to flow into the CVTF warmer 55 but not into the heater core 54.

  Other specific configurations of each part can be variously modified without departing from the spirit of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a cooling water system of a water-cooled internal combustion engine mounted on a vehicle and its control.

0 ... Control device (ECU)
54: Heater core 55: Heat exchanger (CVTF warmer)
57 ... Control valve (FSV)
d: outside temperature signal f: cooling water temperature signal g: fluid temperature signal m: valve opening / closing control signal

Claims (1)

In a cooling water system of a water-cooled internal combustion engine mounted on a vehicle,
A heater core for exchanging heat with the air in the vehicle compartment and heat for exchanging heat with the fluid in accordance with the current cooling water temperature, the outside air temperature, and the temperature of the fluid used for the transmission of the drive system of the vehicle. A control device that controls whether cooling water is allowed to flow through the exchanger.

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