U.S. patent application number 13/421369 was filed with the patent office on 2012-09-20 for vehicular heating system.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Asami Okamoto, Koji Ota.
Application Number | 20120234932 13/421369 |
Document ID | / |
Family ID | 46827682 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120234932 |
Kind Code |
A1 |
Okamoto; Asami ; et
al. |
September 20, 2012 |
VEHICULAR HEATING SYSTEM
Abstract
A vehicular heating system comprising a passenger compartment
air-conditioner and a radiative heater which heats a foot area of a
passenger, said vehicular heating system detecting foot vent heat
which said foot vent air flow has and controlling said passenger
compartment air-conditioner and said radiative heater in accordance
with that heat.
Inventors: |
Okamoto; Asami;
(Kariya-city, JP) ; Ota; Koji; (Kariya-city,
JP) |
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
46827682 |
Appl. No.: |
13/421369 |
Filed: |
March 15, 2012 |
Current U.S.
Class: |
237/2R |
Current CPC
Class: |
F24H 3/102 20130101;
B60H 1/0073 20190501; F24H 3/002 20130101; B60H 1/2218 20130101;
B60H 2001/225 20130101; B60H 1/2226 20190501 |
Class at
Publication: |
237/2.R |
International
Class: |
F24D 19/10 20060101
F24D019/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 16, 2011 |
JP |
2011-058056 |
Mar 16, 2011 |
JP |
2011-058096 |
Claims
1. A vehicular heating system comprising a passenger compartment
air-conditioner with an air-conditioning unit controlling passenger
compartment air-conditioning by calculating a target blowing-out
temperature of said air-conditioning unit in accordance with
information on the environment inside and outside of the passenger
compartment and vehicle operating information, wherein a foot vent
air flow of said air-conditioning unit being adjustable, and a
radiative heater which heats a foot area of a passenger, said
vehicular heating system detecting foot vent heat which said foot
vent air flow has and controlling said passenger compartment
air-conditioner and said radiative heater in accordance with that
heat.
2. A vehicular heating system as set forth in claim 1, wherein the
system controls said passenger compartment air-conditioner and said
radiative heater so that a ratio between the foot vent heat which
said foot vent air flow has and the electric power input to the
radiative heater gives the same warmness sense level at the feet of
the passenger.
3. A vehicular heating system as set forth in claim 2, wherein when
the engine water temperature is a predetermined value or more, the
system makes said foot vent air flow increase and makes the input
electric power of said radiative heater decrease so that the ratio
between the foot vent heat which said foot vent air flow has and
the electric power input to the radiative heater gives the same
warmness sense level at the feet of the passenger and when the
engine water temperature is less than the predetermined value, the
system makes said foot vent air flow decrease and makes the
electric power input to the radiative heater increase so that the
ratio between the foot vent heat which said foot vent air flow has
and the electric power input to the radiative heater gives the same
warmness sense level at the feet of the passengers.
4. A vehicular heating system as set forth in claim 2, wherein when
the engine water temperature is a predetermined value or more, the
system turns said radiative heater OFF, when the engine water
temperature is less than the predetermined value, the system turns
said radiative heater ON and makes said foot vent air flow decrease
and makes the electric power input to said radiative heater
increase so that the ratio between the foot vent heat which said
foot vent air flow has and the electric power input to the
radiative heater gives the same warmness sense level at the feet of
the passengers.
5. A vehicular heating system as set forth in claim 2, wherein said
foot vent air flow is a vent air flow of a foot vent.
6. A vehicular heating system as set forth in claim 2, wherein said
foot vent air flow is a total of the vent air flow of a foot vent
and the vent air flow of a knee vent.
7. A vehicular heating system as set forth in claim 2, wherein said
system adjusts said foot vent air flow by a blower of said
air-conditioning unit.
8. A vehicular heating system as set forth in claim 2, wherein said
system adjusts said foot vent air flow by a door opening degree of
a foot vent of said air-conditioning unit.
9. A vehicular heating system as set forth in claim 2, wherein said
system adjusts said foot vent air flow by a door opening degree of
a knee vent of said air-conditioning unit.
10. A vehicular heating system as set forth in claim 3, wherein
when the engine water temperature is less than a predetermined
value, said system makes said foot vent air flow zero.
11. A vehicular heating system as set forth in claim 2, wherein
said system uses said target blowing-out temperature of the
air-conditioning unit, said temperature setting of the
air-conditioning unit, an outside air temperature, an inside air
temperature, a foot area temperature, or a seat heater temperature
as the basis to control said radiative heater ON and OFF.
12. A vehicular heating system which adjusts a heating element
surface member temperature of a radiative heater which warms a
passenger in accordance with temperature information inside the
passenger compartment, in which vehicular heating system before a
predetermined time elapses from when heating by said vehicular
heating system is turned ON or at the time of elapse, said heating
element surface member temperature is controlled based on a setting
for which a first upper threshold value where the passenger will
not suffer high temperature burn injuries is set and which is set
to increase proportionally or in a monotone functional way in
accordance with temperature information inside the passenger
compartment at below that upper threshold value, and after a
predetermined time elapses from when heating by said vehicular
heating system is turned ON, said heating element surface member
temperature is controlled to not more than a second upper threshold
value where the passenger will not suffer low temperature burn
injuries.
13. A vehicular heating system as set forth in claim 12, wherein
said temperature information inside the passenger compartment is
the target blowing-out temperature of the air-conditioning unit
which controls the passenger compartment air-conditioning in
accordance with information on the environment inside and outside
of the passenger compartment.
14. A vehicular heating system as set forth in claim 12, wherein
said temperature information inside the passenger compartment is
the temperature setting of the air-conditioning unit which controls
the passenger compartment air-conditioning in accordance with
information on the environment inside and outside of the passenger
compartment.
15. A vehicular heating system as set forth in claim 12, wherein
said temperature information inside the passenger compartment is
the temperature setting when an operating mode of the passenger
compartment air-conditioning is manual.
16. A vehicular heating system as set forth in claim 12, wherein
said temperature information inside the passenger compartment is a
foot area temperature.
17. A vehicular heating system as set forth in claim 12, wherein
said temperature information inside the passenger compartment is a
manual temperature setting of said radiative heater.
18. A vehicular heating system as set forth in claim 12, wherein
said temperature information inside the passenger compartment is a
manual temperature setting of a seat heater.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a vehicular heating system
which controls a radiative heater and a car air-conditioner linked
with each other.
[0003] 2. Description of the Related Art
[0004] In the past, it has been known to place a planar heating
element near a foot area of a seat of a vehicle. Japanese
Unexamined Patent Publication No. 2010-64681 discloses a vehicular
heating system which arranges a planar heating element in an
instrument panel of a vehicle so as to heat the inside of the
passenger compartment. This planar heating element is arranged in
the instrument panel corresponding to the knee to foot part of a
seat passenger. At a location corresponding to the foot part side
away from the knee part side, the heating density of the planar
heating element is raised. Due to this, the surface temperature of
the foot part side is raised compared with the knee part side to
apply a larger radiative heat from the foot part side than the knee
part side. However, in this related art, if considering the air
temperature inside of the passenger compartment or simultaneously
using the planar heating element and the car air-conditioner
without linkage with the car air-conditioner, there was the problem
that the warmness sense level at the feet would be insufficient or
too high.
SUMMARY OF THE INVENTION
[0005] To solve the above problems, the aspect of the invention of
claim 1 provides a vehicular heating system comprising a passenger
compartment air-conditioner with an air-conditioning unit
controlling passenger compartment air-conditioning by calculating a
target blowing-out temperature of said air-conditioning unit in
accordance with information on the environment inside and outside
of the passenger compartment and vehicle operating information,
wherein a foot vent air flow of said air-conditioning unit being
adjustable, and a radiative heater which heats a foot area of a
passenger, said vehicular heating system detecting foot vent heat
which said foot vent air flow has and controlling said passenger
compartment air-conditioner and said radiative heater in accordance
with that heat.
[0006] The aspect of the invention of claim 2 provides the aspect
of the invention as set forth in claim 1 wherein the system
controls the passenger compartment air-conditioner and the
radiative heater so that a ratio between the foot vent heat which
the foot vent air flow has and the electric power input to the
radiative heater gives the same warmness sense level at the feet of
the passenger.
[0007] Due to this, it is possible to perform control while linked
with the car air-conditioner, obtain a satisfactory warmness sense
level at the feet, and reduce fuel consumption.
[0008] The aspect of the invention of claim 3 provides the aspect
of the invention as set forth in claim 2, wherein when the engine
water temperature is a predetermined value or more, the system
makes the foot vent air flow increase and makes the input electric
power of the radiative heater decrease so that the ratio between
the foot vent heat which the foot vent air flow has and the
electric power input to the radiative heater gives the same
warmness sense level at the feet of the passenger and when the
engine water temperature is less than the predetermined value, the
system makes the foot vent air flow decrease and makes the electric
power input to the radiative heater increase so that the ratio
between the foot vent heat which the foot vent air flow has and the
electric power input to the radiative heater gives the same
warmness sense level at the feet of the passenger.
[0009] Due to this, by controlling the ratio between the foot vent
heat Qf which the foot vent air flow has and the input electric
power Q of the radiative heater so as to give the same warmness
sense level at the feet of the passenger and using a radiative
heater with a large impact on the warmness sense level even with a
small input electric power, the fuel efficiency is increased.
[0010] The aspect of the invention of claim 4 provides the aspect
of the invention as set forth in claim 2, wherein when the engine
water temperature is a predetermined value or more, the system
turns the radiative heater OFF, and when the engine water
temperature is less than the predetermined value, the system turns
the radiative heater ON and makes the foot vent air flow decrease
and makes the electric power input to the radiative heater increase
so that the ratio between the foot vent heat which the foot vent
air flow has and the electric power input to the radiative heater
gives the same warmness sense level at the feet of the
passenger.
[0011] Due to this, by controlling the ratio between the foot vent
heat Qf which the foot vent air flow has and the input electric
power Q of the radiative heater so as to give the same warmness
sense level at the feet of the passenger and using a radiative
heater with a large impact on the warmness sense level even with a
small input electric power, the fuel efficiency is increased and it
is not necessary to run the engine just for passenger compartment
air-conditioning control.
[0012] The aspect of the invention of claim 5 provides the aspect
of the invention as set forth in claim 2, wherein the foot vent air
flow is a vent air flow of a foot vent.
[0013] The aspect of the invention of claim 6 provides the aspect
of the invention as set forth in claim 2, wherein the foot vent air
flow is a total of a vent air flow of a foot vent and a vent air
flow of a knee vent.
[0014] The aspect of the invention of claim 7 provides the aspect
of the invention as set forth in claim 2, wherein the system
adjusts the foot vent air flow by a blower of the air-conditioning
unit.
[0015] The aspect of the invention of claim 8 provides the aspect
of the invention as set forth in claim 2, wherein the system
adjusts the foot vent air flow by a door opening degree of a foot
vent of the air-conditioning unit.
[0016] The aspect of the invention of claim 9 provides the aspect
of the invention as set forth in claim 2, wherein the system
adjusts the foot vent air flow by a door opening degree of a knee
vent of the air-conditioning unit.
[0017] The aspect of the invention of claim 10 provides the aspect
of the invention as set forth in claim 3, wherein when the engine
water temperature is less than a predetermined value, the system
makes the foot vent air flow zero.
[0018] The aspect of the invention of claim 11 provides the aspect
of the invention as set forth in claim 2, wherein the system uses
the target blowing-out temperature of the air-conditioning unit,
the temperature setting of the air-conditioning unit, an outside
air temperature, an inside air temperature, a foot area
temperature, or a seat heater temperature as the basis to control
the radiative heater ON and OFF.
[0019] The aspect of the invention of claim 12 provides a vehicular
heating system which adjusts a heating element surface member
temperature of a radiative heater which warms a passenger in
accordance with temperature information inside the passenger
compartment, in which vehicular heating system, before a
predetermined time elapses from when heating by the vehicular
heating system is turned ON or at the time of elapse, the heating
element surface member temperature is controlled based on a setting
for which a first upper threshold value where the passenger will
not suffer high temperature burn injuries is set and which is set
to increase proportionally or in a monotone functional way in
accordance with temperature information inside the passenger
compartment at below that upper threshold value, and, after a
predetermined time elapses from when heating by the vehicular
heating system is turned ON, the heating element surface member
temperature is controlled to not more than a second upper threshold
value where the passenger will not suffer low temperature burn
injuries.
[0020] Due to this, to enable safe use without concern about high
temperature burn injuries or low temperature burn injuries, no
matter how the temperature information inside the passenger
compartment is set, the temperature of the heating element 2 of the
radiative heater 1 is automatically controlled to always be no more
than the threshold temperatures for high temperature burn injuries
and low temperature burn injuries. Further, the radiative heater
can sufficiently contribute to raising the temperature of the foot
area in the transitional period and can maintain a predetermined
warmness sense level without concern over low temperature burn
injuries in the steady state period. The radiative heating enables
the legs to be quickly warmed, so this is effective for the
transitional period.
[0021] The aspect of the invention of claim 13 provides the aspect
of the invention as set forth in claim 12, wherein the temperature
information inside the passenger compartment is the target
blowing-out temperature of the air-conditioning unit which controls
the passenger compartment air-conditioning in accordance with
information on the environment inside and outside of the passenger
compartment. Due to this, it is possible to control the surface
member temperature of the heating element of the heating system
while linked with the value of the target blowing-out temperature
in the case of automatic air-conditioning control so as to enable
safe use without concern over high temperature burn injuries and
low temperature burn injuries. In the winter season right after a
passenger gets in the vehicle and feels cold due to the passenger
compartment not being warmed up, the value of the target
blowing-out temperature rises to a high temperature, but even in
this case, the radiative heater is controlled to a high temperature
not causing high temperature burn injuries and therefore the
passenger compartment and foot area are quickly warmed. After this,
as the value of the target blowing-out temperature TAO falls, the
surface member temperature of the heating element of the radiative
heater also automatically falls by the same timing, so the feet can
be efficiently heated. Therefore, it is possible to maintain a
constant warmness sense level at the foot area. Further, there is
no waste in the heating by the radiative heater, so energy is
saved.
[0022] The aspect of the invention of claim 14 provides the aspect
of the invention as set forth in claim 12 wherein the temperature
information inside the passenger compartment is the temperature
setting of the air-conditioning unit which controls the passenger
compartment air-conditioning in accordance with information on the
environment inside and outside of the passenger compartment.
[0023] The aspect of the invention of claim 15 provides the aspect
of the invention as set forth in claim 12, wherein the temperature
information inside the passenger compartment is the temperature
setting when an operating mode of the passenger compartment
air-conditioning is manual.
[0024] The aspect of the invention of claim 16 provides the aspect
of the invention as set forth in claim 12, wherein the temperature
information inside the passenger compartment is a foot area
temperature.
[0025] The aspect of the invention of claim 17 provides the aspect
of the invention as set forth in claim 12, wherein the temperature
information inside the passenger compartment is a manual
temperature setting of the radiative heater.
[0026] The aspect of the invention of claim 18 provides the aspect
of the invention as set forth in claim 12, wherein the temperature
information inside the passenger compartment is a manual
temperature setting of a seat heater.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] These and other objects and features of the present
invention will become clearer from the following description of the
preferred embodiments given with reference to the attached
drawings, wherein:
[0028] FIG. 1 is a schematic view of a vehicular heating system in
one embodiment of the present invention;
[0029] FIGS. 2A and 2B are one example of a radiative heater in one
embodiment of the present invention. FIG. 2A is a plan view and
FIG. 2B is a front view;
[0030] FIG. 3 is one example of a graph which shows the
relationship between a target blowing-out temperature TAO and foot
vent air flow in automatic air-conditioning control;
[0031] FIGS. 4A to 4C are views which show relationships between a
foot vent heat Qf and heater electric power (power consumption) Q
so that the same warmness sense level is obtained, wherein FIGS. 4A
to 4C respectively show the relationships of the heater electric
power, foot vent heat, and fuel efficiency (liter/100 km) with the
foot vent air flow;
[0032] FIG. 5 shows an example of an equation which shows the
interrelationship of a foot vent air flow Va, input electric power
Q of the radiative heater, skin temperature Tsk, etc. in the case
of a targeted warmness sense level P;
[0033] FIG. 6 is a conceptual flowchart of a modification of a
second embodiment of the present invention;
[0034] FIG. 7A is an example of a graph which shows the
relationship of a target blowing-out temperature TAO and a surface
member temperature T of the heating element 2 in a transitional
period where the elapsed time t is t1 or less, while FIG. 7B is an
example of a graph which shows the relationship of a target
blowing-out temperature TAO and a surface member temperature T of
the heating element 2 in a steady state period where the elapsed
time t is over t1;
[0035] FIG. 8 is a graph which shows the relationship between, from
the top, a foot area temperature, heating element surface member
temperature, and warmness sense level with time;
[0036] FIG. 9 is an explanatory view of one example of a method of
converting a burn injury threshold temperature at a skin
temperature to the surface member temperature T of the heating
element 2;
[0037] FIG. 10 is one example of the relationship between low
temperature burn injuries and time; and
[0038] FIG. 11 is a conceptual flow chart of an embodiment of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Below, embodiments of the present invention will be
explained while referring to the drawings. In the embodiments, the
same components are assigned the same reference notations and
explanations are omitted.
[0040] FIG. 1 is a schematic view of a vehicular heating system in
one embodiment of the present invention. A radiative heater 1 is
arranged near the top of the feet of the driver at the wall surface
below the steering wheel column in the vehicle. FIGS. 2A and 2B
show one example of a radiative heater in one embodiment of the
present invention. A heating element 2, as shown in FIG. 2, is
comprised of an electric heater wire arranged in a snaking fashion.
This is formed sandwiched between a surface member and a burn
preventing member 3 (material with low heat transfer coefficient).
For the heating element 2, instead of an electric heating wire, it
is possible to use a heater formed by a resistance member with a
PTC (positive temperature coefficient) property formed into a sheet
shape.
[0041] The vehicular air-conditioning system is comprised of a
refrigeration cycle which is comprised of a compressor which is
driven by the vehicle drive engine, a condenser, a receiver, an
expansion valve, and an evaporator and of an air-conditioning unit
(HVAC). The air-conditioning unit has attached to it a blower unit
which has blowers and has a plastic air-conditioner case which
forms air passages by which air is blown toward the inside of the
passenger compartment. Inside this air-conditioner case, an
evaporator is housed as a cooling-use heat exchanger and a heater
core is housed as a heating use heat exchanger. By controlling the
opening degree of an air mix door which is housed inside of the
air-conditioning unit (HVAC), the temperature of the air is
adjusted to blow air-conditioned air out from defroster vents, face
vents, foot vents, and knee vents. Knee vents are sometimes
provided and sometimes not, but when there are knee vents, a door
is provided for adjusting the ratio of flow rates of the foot vents
and the knee vents.
[0042] The air-conditioning unit is controlled by an
air-conditioning controller ECU. This air-conditioning controller
ECU receives as inputs from an inside air temperature sensor,
outside air temperature sensor, sunlight sensor which detects the
amount of sunlight, and other sensors which detect the heat load of
the vehicle, signals such as a detection signal Trm (passenger
compartment temperature), Tam (outside air temperature), Ts
(sunlight strength signal), etc. and receives as input a
temperature setting Tset etc. as control signals from an
air-conditioning control panel provided inside the instrument
panel. Vehicle operating information, the temperature of an
evaporator in the refrigeration cycle, etc. are also input. The
air-conditioning controller ECU controls the operating mode, vent
mode, blow-out temperature, blowing amount, etc. of the
air-conditioned air which is blown out from the air-conditioning
unit to the inside of the passenger compartment. To heat the foot
area, usually foot vents 11 are provided, but as shown in FIG. 1,
both foot vents 11 and knee vents 12 may also be provided.
[0043] In automatic air-conditioning control, the air-conditioning
controller ECU detects the current passenger compartment
temperature, outside air temperature, sunlight strength, and other
conditions of the environment inside and outside of the passenger
compartment and calculates what temperature the air from the
air-conditioning unit is now compared with the temperature which a
passenger desires (above temperature setting Tset). This calculated
value is called the "target blowing-out temperature TAO" and is a
value forming the basis of automatic air-conditioning control (as
the general formula of the target blowing-out temperature TAO,
target blowing-out temperature=KsetTset-KrTrm--KamTam-KsTs+C, where
Kset, Kr, Kam, and Ks are gains of the signals and C is a
constant). Note that, the general air-conditioning control by
air-conditioning units and the control of automatic
air-conditioners are described in detail in "Automotive Air
Conditioning" (Tokyo Denki University Press, Kenichi Fujiwara et
al., Sep. 9, 2009), pages 88 to 94. The air-conditioning control by
an air-conditioning unit in one embodiment of the present invention
is not limited to the basic control such as in "Automotive Air
Conditioning" and can be applied to modifications of this as
well.
[0044] The air-conditioning control panel is provided with an A/C
switch for turning air-conditioner operation ON/OFF, an auto
air-conditioning switch which switches the operating mode between
automatic/manual, ON/OFF switches and manual setters (digital
settings or dial settings) for the foot use radiative heater and
seat heater, etc. The temperature setting Tset functions in the
case where the operating mode is automatic or manual. The
information on the environment inside and outside of the passenger
compartment indicates the outside air temperature, inside air
temperature, target blowing-out temperature TAO, temperature
setting Tset, manual temperature setting of the radiative heater or
seat heater, foot area temperature, humidity, etc. The vehicle
operating information is selected in accordance with need from a
broad range of information relating to the vehicle such as the
engine water temperature, evaporator temperature in the
refrigeration cycle, vehicle speed, air-conditioning operating
mode, and vent mode.
First Embodiment
[0045] Next, the unique features of radiative heating will be
explained, then an embodiment of the present invention will be
explained. As shown in FIGS. 2A and 2B, the radiative heater 1 in
one embodiment of the present invention is placed near the top of
the feet of the driver in the wall surface under the steering wheel
column of the vehicle. This efficiently heats the foot parts, which
are particularly susceptible to cold and heat in the body, locally
by mainly radiant energy.
[0046] This embodiment of the present invention makes good use of
such features of the radiative heater and aims at satisfying the
warmness sense level of the feet while realizing fuel savings by
control linked with the car air-conditioner.
[0047] An electric heater or other radiative heater uses radiative
heat for heating. Therefore, unlike when blowing warm air to warm
the legs, a small amount of heat gives the same warmness sense
level, so the thermal efficiency is good. A warmness sense level
obtained by consuming a high electric power in the foot mode of the
vehicular air-conditioning system is obtained at the same warmness
sense level by lower electric power by the radiative heater.
Therefore, if using a radiative heater, the fuel consumption is
improved.
[0048] FIG. 3 is an example of a graph which shows the relationship
between a target blowing-out temperature TAO and a foot vent air
flow in automatic air-conditioning control. Note that, in the
present invention, the "vent air flow" indicates the air flow per
unit time (m.sup.3/h). In the case of there being a knee vent, the
foot vent air flow is the total of the foot vent air flow and knee
vent air flow.
[0049] In automatic air-conditioning control, as seen in FIG. 3,
the general practice is to automatically determine the vent air
flow in accordance with the target blowing-out temperature TAO. In
the present invention, the usual vent air flow in automatic
air-conditioning control is deliberately changed and a radiative
heater is used to make up for the decreased warmness sense level
and as a result give the same warmness sense level. By using a
radiative heater, it is possible to make the fuel efficiency
increase. Note that, to adjust the vent air flow compared with the
normal flow as seen in FIG. 3, it is possible to adjust the blower
of the air-conditioning unit (HVAC), the door opening degree of the
foot vent, the door opening degree of the knee vent, or the door
opening degrees of the two.
[0050] The vehicular heating system of the present embodiment is a
system which calculates the target blowing-out temperature TAO of
the air-conditioning unit HVAC in accordance with information on
the environment inside and outside of the passenger compartment and
vehicle operating information and controls the passenger
compartment air-conditioning. It is provided with a passenger
compartment air-conditioner which can adjust the foot vent air flow
of the air-conditioning unit (HVAC) and a radiative heater which
heats the foot area of a passenger. Further, it controls the
passenger compartment air-conditioner and the radiative heater so
that the ratio of the foot vent heat Qf which the foot vent air
flow has and the input electric power Q of the radiative heater
gives the same warmness sense level at the feet of the passenger.
Here, the "same warmness sense level" may be not only the warmness
sense level of a specific temperature, but also the same warmness
sense level having a certain degree of range of warmness sense
level. Further, the same warmness sense level targeted is suitably
set to "slightly warm", "neutral", etc.
[0051] FIGS. 4A to 4C are views which show the relationships of the
foot vent heat Qf and the heater electric power (power consumption)
Q designed to give the same warmness sense level. FIGS. 4A to 4C
respectively are views which show the relationships of the heater
electric power, foot vent heat, and fuel consumption (liters/100
km) with the foot vent air flow. In the case of most vehicles, the
fuel consumption becomes the smallest when the foot vent air flow
is zero, but depending on the characteristics of the vehicle, a
peak value (minimum power consumption) appears at a certain foot
vent air flow as shown in the following formula:
Foot vent heat (Qf)+input electric power of radiative heater
(Q)=minimum power consumption
[0052] Therefore, the ratio of air flows is adjusted so that the
total fuel consumption due to the radiative heater and the
air-conditioner becomes the minimum while satisfying the warmness
sense level.
[0053] Further, in the case of FIGS. 4A to 4C, "the same warmness
sense level to be held" is the warmness sense level due to the foot
vent air flow in the case where the vent air flows of the different
parts are automatically determined in accordance with the target
blowing-out temperature TAO in the air-conditioning unit (HVAC) at
the time when the radiative heater (heater) is OFF (FIG. 3). The
same warmness sense level to be held is not limited to this. It may
also be suitably and freely set (the same warmness sense level to
be held in this case is determined by the warmness sense level
which is determined by the heater at the time of zero foot air
flow). It is also possible to constantly maintain a comfortable
warmness sense level (for example, warmness sense level 1=slightly
warm).
[0054] In this way, the embodiment of the present invention
features control of the ratio of the foot vent heat Qf which the
foot vent air flow has and the input electric power Q of the
radiative heater so as to give the same warmness sense level at the
feet of the passenger. That is, the present embodiment deliberately
reduces the vent air flow by using a radiative heater and performs
control so that the same warmness sense level can be held. Due to
this, by using a radiative heater which has the large effect of
giving a warmness sense level even with little input electric
power, it is possible to make the fuel efficiency increase.
Second Embodiment
[0055] The next second embodiment considers not only the fuel
efficiency due to the characteristics of the radiative heater, but
also the characteristics of the vehicle so as to control the
passenger compartment air-conditioner and the radiative heater. The
air-conditioning unit (HVAC) houses a heater core which acts as a
heat exchanger for heating use. This heater core uses the cooling
water (warm water) of the vehicle driving motor as a heat source
for heating the air. When the engine water temperature of the
cooling water of the engine is around a certain predetermined
threshold value and the heat source which is used for heating is
switched as explained next, the thermal efficiency rises and in
turn the fuel economy can be realized.
[0056] When utilizing the heater core of the air-conditioning unit
(HVAC) for heating, if there is an extra margin of heat as a heat
source in the cooling water (warm water) (when the engine water
temperature is a certain predetermined value or more), no problem
arises in thermal efficiency by utilizing the cooling water (warm
water) as a heat source. However, when the cooling water (warm
water) no longer has a sufficient margin of heat as a heat source
(when the engine water temperature is less than a predetermined
value), sometimes a command is issued to deliberately raise the
engine speed for passenger compartment air-conditioning control. In
particular, in hybrid vehicles (HV's), cars with idling stop
systems, and other vehicles in which there are many opportunities
for stopping the engine, when there is no longer a sufficient
margin of heat as a heat source in the cooling water (warm water),
a command is issued to deliberately run the engine for the
passenger compartment air-conditioning control. This is not
preferable from the viewpoint of the fuel consumption costs. The
second embodiment makes improvements to this situation so as to
realize lower fuel consumption costs.
[0057] That is, when a heat source which can be utilized for
heating is sufficiently present in the engine cooling water which
flows to the heater core (when the engine water temperature is a
certain predetermined value or more), to obtain the same targeted
warmness sense level, in heating the foot area of the passengers,
the heating is performed by the flow of air which is blown toward
the feet in the air-conditioning unit (HVAC). Conversely, if there
is no longer an extra margin of heat as a heat source in the
cooling water (when the engine water temperature is less than a
certain predetermined value), the ratio of the input electric power
Q of the radiative heater is made to increase.
[0058] If considering this state in terms of the thermal efficiency
of the vehicle as a whole, when the engine water temperature is a
certain predetermined value or more, for the heat source for
heating use, since the engine cooling water has excess heat, the
heater core should be relied on more and the input electric power
of the radiative heater should be decreased. Further, if the engine
water temperature is less than a certain predetermined value,
conversely, the input electric power of the radiative heater is
made to increase. Due to this, it is possible to avoid ending up
running the engine unnecessarily for the passenger compartment
air-conditioning control.
[0059] When the engine water temperature is a predetermined value
or more, the present embodiment makes the foot vent air flow
increase and makes the input electric power of the radiative heater
decrease so that the ratio of the foot vent heat Qf which the foot
vent air flow has and the input electric power Q of the radiative
heater gives the same warmness sense level at the feet of the
passenger. When the engine water temperature is less than the
predetermined value, it makes the foot vent air flow decrease and
makes the input electric power of the radiative heater increase so
that the ratio of the foot vent heat Qf which the foot vent air
flow has and the input electric power Q of the radiative heater
gives the same warmness sense level at the feet of the passenger.
As the predetermined value of the threshold value of the engine
water temperature, while governed by the specifications and
characteristics of the vehicle, about 50 to 60.degree. C. or so may
be set by experience as a good rule of thumb.
[0060] As explained later, with a radiative heater, low temperature
burn injuries and high temperature burn injuries (instant burn
injuries) sometimes occur. That is, for the skin temperature Tsk at
the feet, there is a safe temperature comprised of a threshold
temperature. It is also possible to set the input electric power Q
of the radiative heater in FIG. 4A from this safe temperature. In
this case, the foot vent air flow is determined so as to give the
same warmness sense level at the feet of the passenger. It is
therefore possible to determine the foot vent heat Qf.
[0061] It is also possible to suitably make the foot vent air flow
increase or decrease and set the foot vent heat Qf and the input
electric power Q of the radiative heater to give the same warmness
sense level at the feet of the passenger based on the foot vent air
flow determined from the relationship between the target
blowing-out temperature TAO and the foot vent air flow in the
automatic air-conditioning control of FIG. 3. As shown in FIG. 4C,
when the engine water temperature is less than the predetermined
value, it is also possible to make the foot vent air flow zero. In
this case, the fuel consumption becomes the smallest.
[0062] FIG. 5 is one example of a formula which shows the
interrelationship of the foot vent air flow Va, the input electric
power of the radiative heater (heater electric power) Q, skin
temperature Tsk, etc. in the case of a target warmness sense level
P. This calculates the required radiative energy for reaching the
feet from the amount of heat radiated to the feet when the heater
(radiative heater) is turned ON so as to obtain the relationship
with the required heater electric power when satisfying the foot
warmness sense level P. Using such a formula, it is possible to map
the amount of change of the foot vent air flow and the input
electric power Q of the radiative heater (heater electric power).
In this case, it is possible to determine the foot air flow giving
the smallest fuel consumption when the radiative heater is ON from
FIG. 4C and determine the heater electric power Q and foot vent
heat Qf from FIG. 4A and FIG. 4B. FIGS. 4A to 4C may be prepared in
advance so that the skin temperature becomes the safe temperature
or less at the same warmness sense level at the feet of the
passenger.
[0063] As a modification of the second embodiment, it is also
possible to turn the radiative heater OFF when the engine water
temperature is a predetermined value or more and turn the radiative
heater ON when the engine water temperature is less than the
predetermined value and make the foot vent air flow decrease and
make the input electric power of the radiative heater increase so
that the ratio between the foot vent heat Qf which the foot vent
air flow has and the input electric power of the radiative heater
gives the same warmness sense level at the feet of the
passenger.
[0064] FIG. 6 is a conceptual flowchart of the modification of the
second embodiment of the present invention.
[0065] At step 100, it is judged if the engine water temperature is
a predetermined value or more. If NO, the routine proceeds to step
101 where the radiative heater is turned ON, then the routine
proceeds to step 102. If YES, the routine proceeds to step S104
where the radiative heater is turned OFF. At step 102, a map is
utilized to find the amount of change of the foot vent air flow,
then at step 103, a door opening degree and input electric power Q
of the radiative heater are determined.
[0066] In the flowchart of other embodiments of the present
invention, at step 100, instead of the engine water temperature,
any of the target blowing-out temperature (TAO) of the
air-conditioning unit (HVAC), the temperature setting of the
air-conditioning unit (HVAC), the outside air temperature, the
inside air temperature, the foot area temperature, or the seat
heater temperature may be used as an alternative
[0067] The present invention is mainly used in the winter season,
but is not limited to the winter season and may of course also be
used in the intermediate periods (spring and fall). As another
embodiment, it is also possible to automatically switch the
radiative heater ON/OFF in accordance with the target blowing-out
temperature (TAO). That is, when the target blowing-out temperature
is high, it is judged that it is the summer and the radiative
heater is turned OFF, while when the target blowing-out temperature
is low, it is judged that it is the winter and the radiative heater
is turned ON.
[0068] In addition, the temperature setting of the air-conditioning
unit (HVAC), the outside air temperature, the inside air
temperature, the foot area temperature (value estimated by foot
sensor and target blowing-out temperature etc.), or the seat heater
temperature may be used as the basis for ON/OFF control of the
radiative heater.
Third Embodiment
[0069] As shown in FIGS. 2A and 2B, when using the radiative heater
1, it is necessary that it be able to be used safely without
concern over high temperature burn injuries and low temperature
burn injuries. "High temperature burn injuries" mean burn injuries
which instantaneously are caused, while "low temperature burn
injuries" are burn injuries in which for example the skin is in
contact with a 44.degree. C. heat source for 6 hours whereupon the
cells at that part are destroyed down deep under the skin resulting
in burn injuries.
[0070] It is known that right after a passenger gets in a vehicle
in the winter season, he or she easily feels cold due to the
passenger compartment not being warmed up. Therefore, in
particular, the foot parts are heated by local radiative heating
using the radiative heater 1. In such a case, at the start of the
heating, there is a concern that the temperature of the heating
element 2 of the radiative heater 1 will rapidly rise and cause
high temperature burn injuries. If heating the foot parts over a
long period of time using the radiative heater 1, low temperature
burn injuries will sometimes be caused. In the present embodiment,
to enable safe use without concern as to such high temperature burn
injuries and low temperature burn injuries, no matter how the
temperature information inside the passenger compartment such as
the target blowing-out temperature TAO, temperature setting
T.sub.set, manual temperature setting of a radiative heater or seat
heater, foot area temperature, etc. are set, the temperature of the
heating element 2 of the radiative heater 1 is automatically
controlled to be not more than the threshold temperatures for the
high temperature burn injuries and low temperature burn
injuries.
[0071] As a third embodiment of the present invention, the case
where a radiative heater 1 is arranged for heating the foot parts
and automatic air-conditioning control is performed will be
explained.
[0072] At the start of heating, the foot parts are not sufficiently
heated by just the air-conditioning unit (HVAC), so control is
performed so that the temperature of the heating element 2 of the
radiative heater 1 is rapidly raised and the foot parts, which are
particularly susceptible to cold and heat in the body, are warmed.
At this time, the temperature of the heating element 2 rises to
over the low temperature burn injury threshold temperature where
the skin surface will not suffer from low temperature burn
injuries, but is maintained at less than the high temperature burn
injury threshold temperature where the skin surface will not suffer
from high temperature burn injuries.
[0073] FIG. 7A is one example of a graph which shows the
relationship between the target blowing-out temperature TAO and the
surface member temperature T of the heating element 2 at the
transitional period where the elapsed time t from when the heating
element 2 of the radiative heater 1 turned ON is t.sub.1 or less,
while FIG. 7B is one example of a graph which shows the
relationship between the target blowing-out temperature TAO and the
surface member temperature T of the heating element 2 at the steady
state period where the elapsed time t exceeds t.sub.1.
[0074] As shown in FIG. 7A, when the elapsed time t is t.sub.1 or
less, the heating element 2 of the radiative heater 1 is controlled
to not more than the high temperature burn injury threshold
temperature at which the skin surface will not suffer from high
temperature burn injuries converted to the surface member
temperature T of the heating element 2, that is, the high
temperature burn injury threshold temperature T.sub.1 (first upper
limit value at which passengers will not suffer high temperature
burn injuries).
[0075] When, finally, the inside of the passenger compartment is
warmed, the target blowing-out temperature TAO falls. In this case,
as shown in FIG. 7A, the surface member temperature T of the
heating element 2 is also made to fall automatically proportional
to the target blowing-out temperature TAO. If the inside of the
passenger compartment is warmed and gradually approaches the
temperature which the passenger desires, the target blowing-out
temperature becomes a predetermined value .alpha..sub.0 or less and
there is no longer a need to turn on the heating element 2. The
heating element 2 is forcibly turned OFF. Note that, the
predetermined value .alpha..sub.0 may be suitably set by experience
from the need to turn the heating element 2 ON.
[0076] On the other hand, in the steady state period after the
elapsed time T from when the heating element 2 of the radiative
heater 1 was turned ON exceeds t.sub.1 (in general, after about 1
or 2 hours), this time there is a concern over low temperature burn
injuries. Therefore, as shown in FIG. 7B, the surface member
temperature T of the heating element 2 is maintained at not more
than the low temperature burn injury threshold temperature at which
the skin surface will not suffer from low temperature burn injuries
converted to the surface member temperature T of the heating
element 2, that is, the low temperature burn injury threshold
temperature T.sub.2 (second upper limit value at which passengers
will not suffer low temperature burn injuries). In the same way as
in FIG. 7A, if the target blowing-out temperature becomes a
predetermined value .alpha..sub.0 or less, there is no longer a
need for turning on the heating element 2, so the heating element 2
is forcibly turned OFF. Note that, instead of FIG. 7B, control to
any certain value of the low temperature burn injury threshold
temperature T.sub.2 or less may be performed.
[0077] In a vehicular heating system in which the radiative heater
1 is provided for heating the leg parts, when performing automatic
air-conditioning control, it is possible to control the surface
member temperature T of the heating element 2 of the radiative
heater 1 while linked with the value of the target blowing-out
temperature TAO. Due to this, safe use is possible without concern
over high temperature burn injuries and low temperature burn
injuries. In the winter season right after a passenger gets in the
vehicle and feels cold due to the passenger compartment not being
warmed up, the value of the target blowing-out temperature rises to
a high temperature, but even in this case, the radiative heater is
controlled to not more than the high temperature burn injury
threshold temperature where high temperature burn injuries are not
suffered and therefore the passenger compartment and feet area are
quickly warmed.
[0078] After this, as the value of the target blowing-out
temperature TAO falls, the surface member temperature T of the
heating element 2 of the radiative heater 1 also automatically
falls by the same timing, so the feet can be efficiently heated
without waste. In this way, it is possible to maintain the warmness
sense level in the foot area constant. Further, there is no waste
in the heating by the heating element 2 of the radiative heater 1,
so energy is saved. Further, in the steady state period when the
elapsed time t exceeds t.sub.1, it is possible to maintain the
warmness sense level of the foot area constant while enabling use
without concern over low temperature burn injuries due to use of
the radiative heater 1.
[0079] FIG. 8 is a graph which shows the relationship of the foot
area temperature, the heating element surface member temperature,
and the warmness sense level with time. FIG. 8 shows one example of
the advantageous effects due to the present embodiment. It is seen
that the heating element surface member temperature at the center
part compensates well for the delay in the rise of the foot area
temperature and contributes to improvement of the warmness sense
level. In this way, the radiative heater 1 contributes well to the
rise of the temperature at the foot area in the transitional period
and enables a predetermined warmness sense level to be kept without
concern over low temperature burn injuries in the steady state
period.
[0080] Next, the relationship of the burn injury threshold
temperatures at which the skin surface will not suffer from high
temperature burn injuries or low temperature burn injuries and the
surface member temperature T of the heating element 2 and also the
elapsed time t.sub.1 will be explained briefly. There are many
findings regarding high temperature burn injuries (instant burn
injuries), but from the research findings of J.D. Hardy etc., the
high temperature burn injury threshold temperature is set to a skin
temperature of 60.degree. C. In addition, it may be set around
60.degree. C. or below that. Regarding low temperature burn
injuries, it is known that if the skin is in contact with a
44.degree. C. heat source for about 6 hours, the cells of that part
will be destroyed down to a deep part under the skin and burn
injuries will result. When viewed by the temperature in the skin
and under the skin, burn injuries occur at 41.7.degree. C. or more.
From this, as one example, the low temperature burn injury
threshold temperature is set to a temperature of the skin of
41.7.degree. C., but it is also possible to set this at 40.degree.
C. or less for safety. Whatever the case, there are numerous
discoveries regarding the high temperature burn injury threshold
temperature and the low temperature burn injury threshold
temperature. These may be determined by considering these.
[0081] FIG. 9 is an explanatory view of one example of a method for
converting the burn injury threshold temperature at the temperature
of the skin to a surface member temperature T of the heating
element 2. It is possible to convert the burn injury threshold
temperature at the temperature of the skin to the surface member
temperature T from the heat transfer coefficient or thickness of
the surface member of the heating element 2, so the radiative
heater 1 is controlled as shown in FIGS. 7A and 7B by the heating
element surface member temperature of the radiative heater 1 (high
temperature burn injury threshold temperature T.sub.1 and low
temperature burn injury threshold temperature T.sub.2). The high
temperature burn injury threshold temperature T.sub.1 is a first
upper limit value where the passengers will not suffer from high
temperature burn injuries, while the low temperature burn injury
threshold temperature T.sub.2 is a second upper threshold value
where the passengers will not suffer from low temperature burn
injuries. The heating element surface member temperature of the
radiative heater 1 may be detected by a sensor, but the current
value of the heating element may be used instead.
[0082] FIG. 10 is one example of a graph showing the relationship
between low temperature burn injuries and time. Between 44 to
51.degree. C., it is said that for every 1 degree rise in
temperature of the heat source, the time which is required until a
burn is caused is halved. Therefore, the time until suffering low
temperature burn injuries cannot be unambiguously determined, so it
is sufficient to refer to a graph such as FIG. 10 and suitably
determine the elapsed time t.sub.1 from when the heating element 2
of the radiative heater 1 is turned ON (critical point between
transitional period and steady state period, switching point of
control between FIG. 7A and FIG. 7B).
[0083] As other embodiments of the present invention, the following
may be considered: In the above explanation, the radiative heater 1
was controlled linked with the temperature information of the value
of the target blowing-out temperature TAO in automatic
air-conditioning control, but the invention is not limited to this.
Instead of the target blowing-out temperature TAO, it is also
possible to utilize as the temperature information a temperature
setting T.sub.set at the time of automatic air-conditioning control
to perform control the same as FIG. 7A and FIG. 7B. Furthermore,
the temperature information may also be a temperature setting in
the case of switching the operating mode to manual.
[0084] When the seat of a passenger is provided with a seat heater
and the temperature setting of the seat heater can be set by a dial
etc., the temperature setting of the seat heater may also be used
as the temperature information. A "seat heater" is a heater which
uses electric heating wires which are embedded in a seat so as to
warm the seat. The radiative heater 1 is controlled in the same way
as FIGS. 7A and 7B while linked with the temperature information of
the temperature setting of the seat heater. In this case, the
surface member temperature T of the heating element 2 of the
radiative heater 1 is controlled as shown in FIGS. 7A and 7B while
linked with the temperature setting of the seat heater. The
temperature of a seat heater itself, in the same way as the surface
member temperature T of the heating element 2, is limited by the
elapsed time t to the high temperature burn injury threshold
temperature T.sub.1 and the low temperature burn injury threshold
temperature T.sub.2 or less.
[0085] Similarly, even if providing a sensor which detects the
temperature of the foot area, it is possible to control the
radiative heater 1 in the same way as in FIGS. 7A and 7B while
linked with the temperature information of the temperature of the
sensor which detects the temperature of the foot area. Similar
control is also possible by estimating the foot area temperature
from the value of the target blowing-out temperature TAO in
addition to the sensor.
[0086] As explained above, it is possible to use various values as
the temperature information and possible to control the surface
member temperature T of the heating element 2 of the radiative
heater 1 as shown in FIGS. 7A and 7B while linked to these
temperature information. The temperature information is not limited
to the information illustrated above.
[0087] FIG. 11 is a conceptual flowchart of an embodiment of the
present invention. At step S100, it is judged if the elapsed time t
from when the heating element 2 of the radiative heater 1 turns ON
is t.sub.1 or less. If YES, the routine proceeds to step S101,
while if NO, the routine proceeds to step S102. At step S101 and
step S102, it is judged if the temperature information indicates
that the heating element 2 of the radiative heater 1 should be
turned OFF. If YES, at step S105, it is turned OFF. At step S101
and step S102, if NO, the routine respectively proceeds to step
S103 and step S104 where the control of FIGS. 7A and 7B is
performed.
[0088] While the invention has been described with reference to
specific embodiments chosen for purpose of illustration, it should
be apparent that numerous modifications could be made thereto by
those skilled in the art without departing from the basic concept
and scope of the invention.
[0089] While the invention has been described by reference to
specific embodiments chosen for purposes of illustration, it should
be apparent that numerous modifications could be made thereto by
those skilled in the art without departing from the basic concept
and scope of the invention.
* * * * *