In-vehicle device temperature adjustment apparatus
A temperature adjustment apparatus includes a first temperature adjustment circuit including a first pump to circulate a first heat medium; a second temperature adjustment circuit including a second pump to circulate a second heat medium; and a mixing valve to mix the first and second heat media as a mixed heat medium. The temperature adjustment apparatus calculates a target outflow temperature of the mixed heat medium flowing out to the second temperature adjustment circuit, the ratio of the first heat medium as a flow ratio from rotational speeds of the first and second pumps and an opening degree of the mixing valve, an inflow temperature of the first heat medium and an inflow temperature of the second heat medium from outflow temperatures of the mixed heat medium, an opening degree correction coefficient, a target flow ratio, and a target opening degree of the mixing valve to control the opening degree.
1 . An in-vehicle device temperature adjustment apparatus comprising:
a first temperature adjustment circuit including a first pump configured to circulate a heat medium as a first heat medium to adjust a temperature of a first in-vehicle device;
a second temperature adjustment circuit including a second pump configured to circulate the heat medium as a second heat medium to adjust a temperature of a second in-vehicle device;
a mixing valve mixing the first heat medium flowing in from the first temperature adjustment circuit and the second heat medium flowing in from the second temperature adjustment circuit, at a ratio corresponding to an opening degree, to flow out to each of the first temperature adjustment circuit and the second temperature adjustment circuit as a mixed heat medium;
a valve opening degree sensor detecting the opening degree of the mixing valve;
a first inflow temperature sensor detecting, as a first inflow temperature, a temperature of the first heat medium flowing in from the first temperature adjustment circuit to the mixing valve;
an outflow temperature sensor detecting, as an outflow temperature, a temperature of the mixed heat medium flowing out from the mixing valve to the second temperature adjustment circuit; and
a mixing controller performing opening degree control on the mixing valve to mix the first heat medium and the second heat medium,
wherein the mixing controller includes
a target outflow temperature calculator calculating, as a target outflow temperature, a target value of the outflow temperature based on at least the temperature of the second in-vehicle device,
a flow ratio calculator calculating, as a flow ratio, a ratio of the first heat medium contained in the mixed heat medium flowing out from the mixing valve to the second temperature adjustment circuit, based on a rotational speed of the first pump, a rotational speed of the second pump, and the opening degree of the mixing valve,
a second inflow temperature calculator calculating, as a second inflow temperature, a temperature of the second heat medium flowing in from the second temperature adjustment circuit to the mixing valve, based on the first inflow temperature, the outflow temperature, and the flow ratio,
an opening degree correction coefficient calculator calculating an opening degree correction coefficient defining a relationship between the flow ratio and the opening degree, based on the flow ratio and the opening degree of the mixing valve,
a target flow ratio calculator calculating, as a target flow ratio, a target value of the flow ratio based on the first inflow temperature, the second inflow temperature, and the target outflow temperature,
a target opening degree calculator calculating a target opening degree of the mixing valve based on the opening degree correction coefficient and the target flow ratio, and
a valve drive unit performing opening degree control on the mixing valve based on the target opening degree.
2 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein
the flow ratio calculator calculates the flow ratio based on a relationship between a preset rotational speed ratio of the first pump and the second pump and the opening degree of the mixing valve, and
when the flow ratio is R, the first inflow temperature is Tin1, the second inflow temperature is Tin2, and the outflow temperature is Tout, the second inflow temperature calculator calculates the second inflow temperature Tin2 in accordance with the Equation below:
Tin
2
=
Tout
-
Tin
1
×
R
(
1
-
R
)
.
3 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein
when a ratio N1/N2 between the rotational speed N1 of the first pump and the rotational speed N2 of the second pump is x, the flow ratio is R, a ratio R/Rideal between the flow ratio R and an ideal flow ratio Rideal at a time of flow rates of the first heat medium and the second heat medium being equal is y, and preset coefficients are a and b, the flow ratio calculator calculates the ratio y according to:
y
=
a
×
x
+
b
,
and calculates the ideal flow ratio Rideal from the opening degree of the mixing valve based on a relationship between a preset opening degree of the mixing valve and the ideal flow ratio Rideal, and calculates the flow ratio R according to:
R
=
y
×
Rideal
,
when the first inflow temperature is Tin1, the second inflow temperature is Tin2, and the outflow temperature is Tout, the second inflow temperature calculator calculates the second inflow temperature Tin2 according to:
Tin
2
=
Tout
-
Tin
1
×
R
(
1
-
R
)
.
4 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein
when a ratio N1/N2 between the rotational speed N1 of the first pump and the rotational speed N2 of the second pump is x, the flow ratio is R, a ratio R/Rideal between the flow ratio R and an ideal flow ratio Rideal at a time of flow rates of the first heat medium and the second heat medium being equal is y, and preset coefficients are c, d, and e, the flow ratio calculator calculates the ratio y according to:
y
=
cx
2
+
dx
+
e
,
and calculates the ideal flow ratio Rideal from the opening degree of the mixing valve based on a relationship between a preset opening degree of the mixing valve and the ideal flow ratio Rideal, and calculates the flow ratio R according to:
R
=
y
×
Rideal
,
when the first inflow temperature is Tin1, the second inflow temperature is Tin2, and the outflow temperature is Tout, the second inflow temperature calculator calculates the second inflow temperature Tin2 according to:
Tin
2
=
T
o
ut
-
Tin
1
×
R
(
1
-
R
)
.
5 . The in-vehicle device temperature adjustment apparatus according to claim 3 , wherein the flow ratio calculator sets the ideal flow ratio Rideal as the flow ratio R when the ratio x is 1, and applies, to:
y
=
a
×
x
+
b
,
the coefficients a and b that are each different between a case where x is less than 1 and a case where x is greater than 1.
6 . The in-vehicle device temperature adjustment apparatus according to claim 4 , wherein the flow ratio calculator sets the ideal flow ratio Rideal as the flow ratio R when the ratio x is 1, and applies, to:
Ry
=
cx
2
+
dx
+
e
,
the coefficients c, d, and e that are each different between a case where x is less than 1 and a case where x is greater than 1.
7 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein the flow ratio calculator acquires the rotational speed of the first pump and the rotational speed of the second pump from an existing external apparatus.
8 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein the target outflow temperature calculator, the flow ratio calculator, the second inflow temperature calculator, the opening degree correction coefficient calculator, the target flow ratio calculator, the target opening degree calculator, and the valve drive unit repeat respective processes at predetermined control intervals.
9 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein
the mixing controller further includes
a stabilization determiner determining whether a mixed state of the first heat medium and the second heat medium corresponding to the opening degree control of the mixing valve has been within a predetermined fluctuation range over a predetermined period of time, and
a feedback controller executing feedback control including at least one of an integral term or a differential term, obtained from a deviation between the outflow temperature and the target outflow temperature, and
the feedback controller starts the feedback control when the stabilization determiner determines that the outflow temperature has been within a predetermined fluctuation range over a predetermined period of time after starting of the opening degree control of the mixing valve.
10 . The in-vehicle device temperature adjustment apparatus according to claim 9 , wherein the mixing controller controls the opening degree of the mixing valve to warm the second in-vehicle device when the outflow temperature is lower than the target outflow temperature and the first inflow temperature is equal to or higher than the target outflow temperature.
11 . The in-vehicle device temperature adjustment apparatus according to claim 9 , wherein the mixing controller controls the opening degree of the mixing valve to cool the second in-vehicle device when the outflow temperature is equal to or higher than the target outflow temperature and the first inflow temperature is lower than the target outflow temperature.
12 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein
one of the first temperature adjustment circuit and the second temperature adjustment circuit is a powertrain cooling water circuit that adjusts a temperature of a powertrain for controlling a vehicle to travel, and
the other of the first temperature adjustment circuit and the second temperature adjustment circuit is a battery cooling water circuit for adjusting a temperature of a travel battery.
13 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein
one of the first temperature adjustment circuit and the second temperature adjustment circuit is an air-conditioning core cooling water circuit for adjusting a temperature of an air-conditioning core of a vehicle, and
the other of the first temperature adjustment circuit and the second temperature adjustment circuit is a battery cooling water circuit for adjusting a temperature of a travel battery.
14 . The in-vehicle device temperature adjustment apparatus according to claim 1 , wherein
one of the first temperature adjustment circuit and the second temperature adjustment circuit is an air-conditioning core cooling water circuit for adjusting a temperature of an air-conditioning core of a vehicle, and
the other of the first temperature adjustment circuit and the second temperature adjustment circuit is a powertrain cooling water circuit for adjusting a temperature of a powertrain for controlling the vehicle to travel.
15 . The in-vehicle device temperature adjustment apparatus according to claim 12 , wherein the powertrain is an engine installed in the vehicle as a travel power source.
16 . The in-vehicle device temperature adjustment apparatus according to claim 12 , wherein the powertrain includes a travel motor installed in the vehicle as a travel power source, an inverter for driving the travel motor, and a direct current to direct current (DC-DC) converter.
17 . The in-vehicle device temperature adjustment apparatus according to claim 14 , wherein the powertrain is an engine installed in the vehicle as a travel power source.
18 . The in-vehicle device temperature adjustment apparatus according to claim 14 , wherein the powertrain includes a travel motor installed in the vehicle as a travel power source, an inverter for driving the travel motor, and a direct current to direct current (DC-DC) converter.