Patent Application
20210301768
The present disclosure relates to a cooling device for a vehicle, and particularly to a cooling device for a vehicle provided with an engine having an exhaust gas recirculation (EGR) system, a supercharger, and an intercooler.
Conventionally, it is known that a circuit has a channel through which coolant for cooling an engine as a power source of a vehicle flows, a channel through which coolant for cooling a motor drive having an electric motor as a power source and its high-voltage components flows, and a channel through which oil for lubricating inside a transmission flows. The circuit exchanges heat between the coolant for cooling the motor drive and the oil for lubricating inside the transmission (e.g., JP2015-001301A).
Here, engines with a supercharger (a turbocharger, a mechanical supercharger, etc.) need to be provided with the supercharger and an intercooler for cooling intake gas containing intake air (fresh air) and EGR gas in order to improve the engine output. If a cooling passage for coolant for cooling a motor drive is branched to the intercooler in order to improve the cooling efficiency of intake gas by the intercooler, the intake gas containing the EGR gas may be cooled to generate condensed water.
Therefore, the present disclosure is made in view of solving the problem described above, and one purpose thereof is to provide a cooling device for a vehicle including an engine with a supercharger and an intercooler, which can suppress an excessive cooling of intake gas containing exhaust gas recirculation (EGR) gas circulating inside the intercooler and can suppress the generation of condensed water.
According to one aspect of the present disclosure, a cooling device for a vehicle is provided, which includes an engine having an EGR system, a supercharger, and an intercooler configured to cool intake gas containing EGR gas, a coolant channel through which coolant for cooling a motor drive flows, the coolant channel having a first channel through which a first coolant for cooling a high-voltage component of the motor drive flows and a second channel through which a second coolant for cooling the intercooler flows, the second channel being branched from the first channel, and a valve provided to the second channel of the coolant channel and configured to adjust a flow rate of the second coolant.
According to this configuration, the coolant channel is provided with the second channel which branches from the first channel for cooling the high-voltage component, and through which the second coolant for cooling the intercooler flows. The second channel is provided with the valve which can adjust the flow rate of the second coolant. This valve adjusts the flow rate of the second coolant according to the temperature of the coolant, the excessive cooling of the intake gas including EGR gas which circulates inside the intercooler cooled by the second coolant can be suppressed, and therefore, the generation of the condensed water can be suppressed.
The cooling device may further include a controller configured to control the valve. The controller may control the valve to lower the flow rate of the second coolant when an intake gas temperature at an outlet of the intercooler is below a given temperature, rather than the flow rate of the second coolant when the intake gas temperature exceeds the given temperature. According to this configuration, since the valve reduces the flow rate of the second coolant for cooling the intercooler when the intake gas temperature at the outlet of the intercooler is below the given temperature rather than the flow rate when the intake gas temperature exceeds the given temperature, the excessive cooling of the intake gas which circulates inside the intercooler can be suppressed, and therefore, the generation of the condensed water can be suppressed.
The controller may control the valve when the intake gas temperature at the outlet of the intercooler is below a given second temperature lower than the given temperature so that the flow rate of the second coolant becomes zero. According to this configuration, since the valve makes the flow rate of the second coolant for cooling the intercooler zero when the intake gas temperature at the outlet of the intercooler is below the given second temperature which is lower than the given temperature, the excessive cooling of the intake gas which circulates inside the intercooler can be suppressed more effectively.
The cooling device may further include a coolant channel for the engine through which coolant for cooling the engine flows. The first channel and the second channel of the coolant channel may be independent from the coolant channel for the engine. According to this configuration, since the first channel for cooling the high-voltage component of the motor drive and the second channel for cooling the intercooler are provided as the separate circuits which are independent from the coolant channel for the engine, the second channel can cool the intercooler by the comparatively cold coolant, without being influenced by the comparatively hot coolant which circulates inside the engine. Thus, the excessive cooling of the intake gas which circulates inside the intercooler can be suppressed more effectively.
The controller may determine whether the intake gas temperature at the outlet of the intercooler is below a given first temperature. When the intake gas temperature is determined to exceed the given first temperature, the controller may control the valve to be fully opened. When the intake gas temperature is determined to be below the given first temperature, the controller may determine whether the intake gas temperature is below a given second temperature lower than the given first temperature. When the intake gas temperature is determined to exceed the given second temperature, the controller may control the flow regulating valve so that the flow rate of the coolant circulating the second channel and the intercooler becomes a second coolant flow rate smaller than a coolant flow rate when the flow regulating valve is fully opened.
When the intake gas temperature is determined to be below the given second temperature, the controller may control the flow regulating valve to be closed so that the flow rate of the coolant circulating the second channel and the intercooler becomes zero.
Hereinafter, cooling devices for a vehicle according to embodiments of the present disclosure will be described with reference to the accompanying drawings.
First, referring to
As illustrated in
The vehicle according to this embodiment is a front-engine rear-wheel-drive (FR) vehicle where the motor 6 is provided between the engine 4 and the transmission 8, and the transmission 8 is a longitudinal transmission provided rearward of the motor 6. The power of the engine 4 and/or the motor 6 is transmitted to the transmission 8, and it is transmitted to rear wheels (not illustrated) through a propeller shaft and a differential device (not illustrated). Although the transmission 8 is an automatic transmission, it may be a manual transmission. Note that the cooling device 1 according to this embodiment of the present disclosure may be also applicable to a front-wheel-drive vehicle having a power transmission system (not illustrated) with a transverse engine and a transverse transmission, as a modification.
Next, as illustrated in
Moreover, the motor 6 of the power transmission system 2 according to this embodiment is connected to a DC-DC converter (a voltage converter or a potential transformer) 16 and an inverter 18 which are high-voltage components for actuating the motor 6, and the motor 6 and the high-voltage components 16 and 18 constitute a motor drive.
Forward of the engine 4 and the motor 6, an air-cooled radiator 20 for high-temperature coolant (HT radiator) (hereinafter, a first radiator) which cools coolant circulating through the engine 4 to cool the engine 4 by using traveling wind (an air flow caused by the vehicle traveling), and an air-cooled radiator 22 for low-temperature coolant (LT radiator) (hereinafter, a second radiator) provided forward of the first radiator 20 and which cools coolant circulating and cooling the DC-DC converter 16, the inverter 18 and the motor 6, and the intercooler 12 by the traveling wind, are provided. Each of the radiators 20 and 22 is a heat exchanger which carries out a heat exchange between the traveling wind and the coolant.
Moreover, as illustrated in
Next, an outline configuration of a heat-exchange circuit for the coolant and the oil including the coolant channel, the oil channel, and the heat exchangers of the cooling device for the vehicle according to the first embodiment of the present disclosure is described with reference to
The first coolant channel 30 is a channel for coolant which circulates and cools the engine 4 and an oil cooler (OC) 28 which cools engine oil inside the engine 4. Here, the engine 4 has the supercharger 10 described above, and bearings of the supercharger 10 are lubricated with engine oil, and the first coolant channel 30 does not pass through the supercharger 10. The second coolant channel 32 is a channel for coolant which circulates and cools the DC-DC converter (DCDC) 16, the inverter (INV) 18 and the motor (MOTOR) 6, and the intercooler 12 (I/C). The intercooler 12 is to cool intake gas containing intake air (fresh air) and EGR gas which is compressed by the supercharger 10 and fed into combustion chambers (not illustrated) of the engine 4, and the intercooler 12 is provided with an intake-gas temperature sensor 13 which detects a temperature of the intake gas at an outlet of the intercooler 12. The oil channel 34 is a channel for the transmission oil which lubricates inside the transmission (TM) 8.
The first coolant channel 30 is described in more detail. The first coolant channel 30 is provided with a water pump 40 which circulates coolant inside the first coolant channel 30. The first coolant channel 30 has two branched channels. First, the first coolant channel 30 has a first channel 30a where coolant circulates through the water pump 40, the engine 4, the first radiator 20, and a thermostat (T/S) 42 as a thermoregulator of the coolant, in this order. The thermostat 42 is a valve which opens when the coolant circulating through the engine 4 is hot enough to be cooled by the radiator 20 so that the coolant circulates through the radiator 20.
The first coolant channel 30 further has a second channel 30b where coolant circulates through the water pump 40, the first heat exchanger 24, the oil cooler 28, and the engine 4, in this order. The first heat exchanger 24 exchanges heat between the coolant which flows through the second channel 30b and the oil (transmission oil) which flows through the oil channel 34.
Next, the second coolant channel 32 is described in more detail. The second coolant channel 32 is provided with a water pump 46 for circulating coolant inside the second coolant channel 32. The second coolant channel 32 has two branched channels. First, the second coolant channel 32 has a first channel 32a where coolant circulates through the water pump 46, the DC-DC converter 16, the inverter 18, the second heat exchanger 26, and the motor 6, in this order. The second heat exchanger 26 exchanges heat between the coolant which flows through the first channel 32a and the oil which flows through the oil channel 34.
Further, the second coolant channel 32 has a second channel 32b which branches from the first channel 32a, joins the first channel 32a at a location downstream of the motor 6. The second channel 32b allows the coolant to circulate through a flow regulating valve/coolant solenoid valve 48 which adjusts a flow rate of the coolant of the second channel 32b, and the intercooler 12, in this order. The flow regulating valve (CSV) 48 is an electromagnetic solenoid valve, and is changeable of a duty ratio by an On-Off control to adjust an opening of this valve.
Next, the oil channel 34 is described in more detail. The transmission 8 is provided with an oil pump (not illustrated) which circulates oil inside the transmission 8 and the oil channel 34. The oil pump (not illustrated) is a known oil pump which supplies transmission oil as lubricant/hydraulic fluid to power transmission components inside the transmission 8 (gears, clutches, etc.).
The oil channel 34 has two branched channels. First, the oil channel 34 has a first channel 34a which circulates oil between the transmission 8 and the first heat exchanger 24. This first channel 34a is also a channel which bypasses the second heat exchanger 26. Further, the oil channel 34 has a second channel 34b which branches at a branch part 34c from the first channel 34a, and circulates the oil which circulated through the transmission 8 and the first heat exchanger 24 to the second heat exchanger 26, and circulates it from the second heat exchanger 26 to the transmission 8.
Moreover, the oil channel 34 is provided with an oil temperature sensor (SN) 50 which detects temperature of the oil. This oil temperature sensor 50 may be provided at any location of the oil channel 34, as long as it can detect the temperature of the oil.
Moreover, a solenoid valve device (SV) 52 which adjusts a flow rate of oil which flows into the second heat exchanger 26 is provided to the second channel 34b of the oil channel 34. The solenoid valve device 52 is an electromagnetic solenoid valve, and is capable of adjusting an opening of the valve by an On-Off control which changes a duty ratio. In this embodiment, the solenoid valve device 52 is configured so that it adjusts its opening to adjust a flow rate of oil which circulates through the first heat exchanger 24 (first oil flow rate) and a flow rate of oil which circulates through the second heat exchanger 26 (second oil flow rate).
For example, the solenoid valve device 52 makes the first oil flow rate larger than the second oil flow rate when the oil temperature is below a given temperature (e.g., 80° C.), and on the other hand, it makes the first oil flow rate smaller than the second oil flow rate when the oil temperature exceeds the given temperature. Note that as one modification, when the oil temperature exceeds the given temperature, it may set so that the first oil flow rate becomes equal to the second oil flow rate. Moreover, the second oil flow rate when exceeding the given temperature may be larger than the second oil flow rate when below the given temperature.
Next, a control procedure of the flow regulating valve 48 in the cooling device according to the first embodiment of the present disclosure is described with reference to
In this embodiment, an output signal related to temperatures of intake gas at the intercooler outlet from the intake-gas temperature sensor 13 (SW11) which is provided to the intercooler 12 as described above, is inputted into the ECU 62. The ECU 62 controls the flow regulating valve 48 based on the output signal from the intake-gas temperature sensor 13 (SW11), as describe later, to control a flow rate of the coolant which circulates inside the intercooler 12.
Moreover, in this embodiment, an output signal related to the temperature of the coolant in the second coolant channel 32 from a coolant temperature sensor SW5 (not illustrated in
Note that an ignition output signal which means a command for an engine start (SW1), an output signal related to an intake air amount from an airflow sensor SW2 provided to the intake passage of the engine 4, an output signal related to an intake-air temperature from an intake air temperature sensor SW3 provided to the intake passage, an output signal related to an intake pressure from an intake pressure sensor SW4 provided to the intake passage, an output signal related to a crank angle from a crank angle sensor SW6 provided to the crankshaft (4a) of the engine 4, an output signal related to an opening of an accelerator pedal from an accelerator opening sensor SW7, an output signal related to a cam angle at the intake side from an intake cam angle sensor SW8 provided to an intake cam shaft (not illustrated), and an output signal related to a cam angle at the exhaust side from an exhaust cam angle sensor SW9 provided to an exhaust cam shaft (not illustrated) are inputted into the ECU 62. Based on the ignition signal (SW1) and the output signals from the various sensors SW2-SW9, the ECU 62 controls a fuel injection timing by controlling an injector 70 of the engine 4, controls an ignition timing by controlling an ignition plug 72 and an auxiliary chamber ignition plug (PCP) 74, controls an air-fuel ratio by controlling a throttle valve 80, a variable valve lift mechanism at the intake side (intake electric S-VT) 76, and/or the injector 70, and controls a flow rate of EGR gas which recirculates to the intake side of the engine 4 by controlling a variable valve lift mechanism at the exhaust side (exhaust electric S-VT) 78 and an EGR valve 82.
Next, a procedure of a control processing executed by the controller (ECU) of the cooling device 1 according to the first embodiment of the present disclosure is described with reference to
Next, the ECU 62 shifts to Step S2 where it determines whether the gas temperature at the intercooler outlet (IC outlet) read at Step S1 is below a given first temperature A (see
Next, if the ECU 62 determines at Step S2 that the gas temperature at the intercooler outlet is below the given first temperature A (YES at Step S2), the ECU 62 shifts to Step S4 where it determines whether the gas temperature at the intercooler outlet is below a given second temperature B which is lower than the given first temperature A. If the ECU 62 determines at Step S4 that the gas temperature exceeds the given second temperature B (NO at Step S4), the ECU 62 shifts to Step S5 where it controls the flow regulating valve 48 so that a flow rate of coolant which circulates to the second channel 32b and the intercooler 12 becomes a second coolant flow rate D (see
Next, if the ECU 62 determines at Step S4 that the gas temperature is below the given second temperature B (YES at Step S4), the ECU 62 shifts to Step S6 where it controls to close the flow regulating valve 48 so that the flow rate of the coolant which circulates to the second channel 32b and the intercooler 12 becomes zero (see
As illustrated by the time chart in
Next, a cooling device according to a second embodiment of the present disclosure is described with reference to
First, as illustrated in
In the second embodiment, as illustrated in
Next, as illustrated in
The first coolant channel 30 is configured similarly to the first embodiment. That is, the first coolant channel 30 is provided with the water pump 40 and it has two branched channels. The first channel 30a of the first coolant channel 30 is a channel where coolant circulates through the water pump 40, the engine 4, the first radiator 20, and the thermostat 42, in this order, and the second channel 30b of the first coolant channel 30 is a channel where coolant circulates through the water pump 40, the first heat exchanger 24, the oil cooler 28, and the engine 4, in this order.
The second coolant channel 32 is configured similarly to the first embodiment. That is, the second coolant channel 32 is provided with the water pump 46, and it has two branched channels. The first channel 32a of the second coolant channel 32 is a channel where coolant circulates through the water pump 46, the DC-DC converter 16, the inverter 18, the second heat exchanger 26, and the motor 6, in this order, and the second channel 32b is a channel which branches from the first channel 32a, and joins the first channel 32a at a location downstream of the motor 6. The first channel 32a allows coolant to circulate through the flow regulating valve 48 which adjusts a flow rate of the coolant, and the intercooler 12, in this order.
The oil channel 34 according to the second embodiment has, similarly to the first embodiment, a first channel 34a which circulates oil between the transmission 8 and the first heat exchanger 24 by an oil pump (not illustrated) provided to the transmission 8, and a second channel 34b which branches from the first channel 34a and which circulates the oil circulated through the transmission 8 and the first heat exchanger 24 to the second heat exchanger 26.
The oil channel 34 according to the second embodiment is provided with a two-way valve (2Way-V) 54, instead of the solenoid valve device 52 of the first embodiment. In more detail, the oil channel 34 is further provided, at a branch part 34c where the second channel 34b branches from the first channel 34a, with the two-way valve 54 for fully separating the oil which flows through the first channel 34a from the oil which flows through the second channel 34b. The two-way valve 54 of the second embodiment is a so-called thermostat, and can adjust an oil flow rate which circulates through the first heat exchanger 24 (first oil flow rate) and an oil flow rate which circulates through the second heat exchanger 26 (second oil flow rate) by being opened and closed according to the oil temperature of the oil channel 34.
For example, when the oil temperature is below the given temperature (e.g., 80° C.), the two-way valve 54 is closed so that the oil circulates only to the first heat exchanger 24, and on the other hand, when the oil temperature exceeds the given temperature, the two-way valve 54 is opened so that the oil circulates to both the first heat exchanger 24 and the second heat exchanger 26.
Next, main operation and effects of the cooling device according to this embodiment of the present disclosure are described. First, in the cooling devices 1 and 100 according to the first embodiment and the second embodiment of the present disclosure, since the coolant channel 32 is provided with the second channel 32b which branches from the first channel 32a for cooling the high-voltage components 16 and 18 and through which the coolant for cooling the intercooler 12 circulates, and the second channel 32b is provided with the adjuster (CSV) 48 which can adjust the flow rate of the coolant, the adjuster 48 can adjust the flow rate of the coolant according to the temperature of the coolant, the excessive cooling of the intake gas including EGR gas which circulates inside the intercooler 12 and is cooled by the coolant can be suppressed, and therefore, the generation of the condensed water can be suppressed.
Moreover, according to the first and second embodiments, since the adjuster 48 reduces the flow rate of the coolant for cooling the intercooler 12 when the intake gas temperature at the outlet of the intercooler 12 is below the given temperature A rather than the flow rate when the intake gas temperature exceeds the given temperature A, the excessive cooling of the intake gas which circulates inside the intercooler 12 can be suppressed, and therefore, the generation of the condensed water can be suppressed.
Moreover, according to the first embodiment, since the adjuster 48 makes the flow rate of the coolant for cooling the intercooler 12 zero when the intake gas temperature at the outlet of the intercooler 12 is below the given second temperature B which is lower than the given temperature A, the excessive cooling of the intake gas which circulates inside the intercooler 12 can be suppressed.
Moreover, according to the first and second embodiments, since the first channel 32a for cooling the high-voltage components 16 and 18 and the second channel 32b for cooling the intercooler 12 are provided as the separate circuits which are independent from the coolant channel 30 for the engine 4, they can cool the intercooler 12 by the comparatively cold coolant, without being influenced by the comparatively hot coolant which circulates inside the engine 4.
It should be understood that the embodiments herein are illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof, are therefore intended to be embraced by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-054595 | Mar 2020 | JP | national |
