Refrigeration – Automatic control – Responsive to vehicle body motion or traction
Reexamination Certificate
2000-11-09
2002-09-17
Wayner, William (Department: 3744)
Refrigeration
Automatic control
Responsive to vehicle body motion or traction
C062S158000, C062S229000, C062S323400
Reexamination Certificate
active
06449965
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle air conditioner, and more particularly, to a vehicle air conditioner that includes a variable displacement compressor.
The compressor in such a vehicle air conditioner according to the publication has a swash plate and is shown in
FIG. 6. A
housing
101
of the compressor includes a front housing member, a center housing member and a rear housing member. A crank chamber
102
is defined in the front housing member. Cylinder bores
113
are defined in the center housing member. A suction chamber
114
and a discharge chamber
115
are defined in the rear housing member. A valve plate
117
is located between the center housing member and the rear housing member. A drive shaft
103
extends through the crank chamber
102
and is supported by the front housing member and the rear housing member.
The drive shaft
103
is coupled to an external drive source, which is a vehicle engine Eg, by an electromagnetic clutch
105
. The clutch
105
is attached to the front end (left end as viewed in the drawing) of the housing
101
. The clutch
105
includes a pulley
106
and an armature
107
. The pulley
106
rotates relative to the housing. The armature
107
is fixed to the drive shaft
103
to rotate integrally therewith. An electromagnet
108
is located in the pulley
106
. When the electromagnet
108
(the clutch
105
is on) is excited, the armature
107
is attracted to the electromagnet
108
and pressed against the pulley
106
, which transmits the power of the engine Eg to the drive shaft
103
. When the electromagnetic
108
is de-excited (the clutch
105
is off), the armature
107
is separated from the pulley
106
, which disconnects the drive shaft
103
from the engine Eg.
A lug plate
109
is arranged to the drive shaft
103
in the crank chamber
102
. The lug plate
109
is fixed to the drive shaft
103
to rotate integrally with the drive shaft
103
. The swash plate
110
is supported on the drive shaft
103
and inclines relative to the axis L of the drive shaft
103
. The swash plate
110
is coupled to the lug plate
109
by a hinge mechanism
111
. A ring
112
is fitted about the drive shaft
103
to prevent the swash plate
110
from moving beyond the minimum inclination position. When contacting the ring
112
, the swash plate
110
is at the minimum inclination position.
Several cylinder bores
113
are located about the drive shaft
103
in the center housing member. A piston
116
is reciprocally housed in each cylinder bore
113
and coupled to the swash plate
110
. Rotation of the drive shaft
103
is converted into reciprocation of each piston
116
by the lug plate
109
, the hinge mechanism
111
and the swash plate
110
. As each piston
116
reciprocates, refrigerant gas is drawn to a compression chamber defined in the associated cylinder bore
113
through a corresponding suction valve, a number of which are formed in the valve plate
117
in correspondence with the bores
113
. The refrigerant is then compressed and discharged to the discharge chamber
115
through a corresponding discharge valve, a number of which are formed in the valve plate
117
in correspondence with the bores
113
.
A through hole is defined in the center housing member to receive an end of the drive shaft
103
. A coil spring
118
is located in the through hole between the end of the drive shaft
103
and the valve plate
117
. The spring
118
urges the drive shaft
103
leftward as viewed in FIG.
6
and compensates for dimensional errors of the parts, which prevents axial chattering in the compressor.
The crank chamber
102
is connected to the suction chamber
114
by a bleed passage
119
. The discharge chamber
115
is connected to the crank chamber
102
by a supply passage
120
. The supply passage
120
is regulated by an electromagnetic control valve
121
. Specifically, the control valve
121
adjusts the opening size of the supply passage
120
to change the flow rate of highly pressurized refrigerant gas flowing from the discharge chamber
115
to the crank chamber
102
. Since the flow rate of refrigerant flowing from the crank chamber
102
to the suction chamber
114
through the bleed passage
119
is lower than that of the refrigerant flowing through the supply passage
120
, the difference between pressures acting on the front and rear ends of each piston
116
, in other words, the difference between the pressure in the crank chamber
102
and the pressure in the compression chambers, is changed. Accordingly, the inclination angle of the swash plate
110
is changed, which changes the stroke of each piston
116
. The displacement of the compressor is varied, accordingly.
A controller
131
includes a microprocessor and controls the electromagnetic clutch
105
and the control valve
121
based on external information. The information includes the passenger compartment temperature detected by a temperature sensor
132
, the target temperature set by a temperature adjuster
133
, which is manipulated by a passenger, and the ON/OFF state of an air-conditioner switch
134
, which is manipulated by an passenger for starting and stopping the air conditioner.
FIG. 7
illustrates the control valve
121
. The control valve
121
has a valve housing
126
, a valve body
122
, springs
125
a
,
125
b
and a solenoid coil
124
. The valve housing
126
has a port
127
, which is connected to the crank chamber
102
by a section of the supply passage
120
, a valve chamber
128
, which is connected to the discharge chamber
115
by another section of the supply passage
120
, and a valve hole
120
a, which connects the valve chamber
128
with the port
127
. The valve body
122
opens and closes the valve hole
120
a
. The spring
125
a
extends between a wall of the valve chamber
128
and the valve body
122
. The spring
125
b
, the force of which is weaker than that of the spring
125
a
, is located below the valve body
122
.
When no current is supplied to the coil
124
, the valve body
122
is moved downward by the force of the spring
125
a
, which completely shuts the supply passage
120
. When a current is supplied to the coil
124
, the valve body
122
is moved upward against the force of the spring
125
a
, which fully opens the supply passage
120
.
When a passenger turns the switch
134
off, the controller
131
stops current to the electromagnet
108
, which disengages the clutch
105
. Accordingly, the compressor is stopped. At the same time, current to the coil
124
is stopped, which causes the control valve
121
to fully close the supply passage
120
.
When the supply passage
120
is fully closed, the pressure in the crank chamber
102
is relatively low. Therefore, if the switch
134
is turned off in this state, the compressor is stopped with the swash plate
110
located at the maximum inclination position, which is shown by solid lines in FIG.
6
. If the compressor is started immediately thereafter, the compressor starts operating with the maximum displacement, which requires the maximum load torque. This increases the load on the engine Eg. Accordingly, a great shock is produced.
SUMMARY OF THE INVENTION
Accordingly, it is an objective of the present invention to provide a vehicle air conditioner that produces no shock when a compressor is started immediately after it is stopped.
To achieve the foregoing and other objectives, the present invention provides an air conditioner for a vehicle having a variable displacement compressor and a controller. The compressor is selectively engaged and disengaged with the power source by an electromagnetic clutch and has a crank chamber accommodating a cam plate. The inclination angle of the cam plate varies based on the pressure of the crank chamber. A piston is coupled to the cam plate to reciprocally move by a stroke based on the inclination angle of the cam plate to compress gas within a compression chamber and discharge the compressed gas to a discharge chamber. The controller controls the displacement of the compressor
Hidaka Shigeyuki
Kawaguchi Masahiro
Koumura Satoshi
Murao Kazushige
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Morgan & Finnegan , LLP
Wayner William
LandOfFree
Vehicle air conditioner does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Vehicle air conditioner, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Vehicle air conditioner will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2839927