Burton H. Bowkamp, Dodge chief engineer and manager of product planning, said the system offers fresh-air cooling in the Dart for the first time, and is engineered as an integral part of the car.
Controls for the system are built into the instrument panel, and passenger compartment heating and cooling components are neatly installed behind the panel, Bowkamp said.
"Front seat foot room is conserved because the floor area remains clear and unobstructed," he said.
The system operates quietly and provides better cool-air distribution than previous factory-installed systems, he said.
"Cool air is felt by front seat occupants because of the high discharge air velocities and the quick response of the refrigerating system to cooling demands," Bowkamp asserted. "Substantially cooled air is obtained within minutes after the system is turned on."
Fresh air ventilators, which are independent of the air-conditioning system, are included in the installation.
From left to right, the five pushbuttons are titled OFF, MAX A/C, A/C, HEAT and DEF.
The OFF button switches off electrical power to the system and closes off incoming fresh air.
MAX A/C is a recirculated-air cooling selection recommended for fast cool-down.
A/C is a fresh-air cooling selection recommended for normal continuous operation after the initial cool-down.
HEAT is a fresh-air selection for normal car heating.
DEF is a fresh-air selection for defrosting or defogging the windshield.
The fan is switched on when any button except off is pushed in. Fan speed is controlled by the toggle switch to the left of the pushbuttons. As it is moved from left to right, the three-position switch permits selection of low, medium or high fan speed.
The slide lever below the pushbuttons controls the temperature and is used for both summer and winter operation. At the extreme left, the lever is in its coolest position; at the extreme right, its warmest position. The lever can be set at any intermediate position to provide the air temperature that feels best to occupants of the car.
Manually operated directional controls are built into each of the three cooling air outlets in the slim unit on the underside of the instrument panel. Each outlet grille can be adjusted to direct air up or down as well as from side to side.
The manually adjusted ventilator doors under the instrument panel at each side of the car should be closed whenever the air conditioning system is being used.
System Components
Components of the air conditioning system are located both under the hood or in the passenger compartment. Most prominent of those in the engine compartment are the compressor, condenser and receiver-dryer.
An integral part of the compressor installation is the magnetic clutch. Driven by a belt from the engine crankshaft pulley, it transmits power to the compressor whenever the air conditioning system is operated in a cooling cycle.
The condenser is in front of the radiator. Because of the added load the condenser imposes on the engine cooling system, Darts equipped with air conditioning have special cooling system components. Included are a larger radiator, a higher capacity fan with box-type shroud and a 16 psi (instead of 14 psi) radiator pressure cap.
Models with V-8 engine, unless they are equipped with a trailer-towing package, have a viscous drive fan with thermal control instead of the solid drive fan.
Other components in the engine compartment include compressor suction and discharge line mufflers, expansion valve and related refrigerant plumbing; heater hoses and flow shut-off valve; and the air conditioning fan drive motor which projects through the dash panel into the engine compartment.
Inside the passenger compartment, two interconnected units are mounted on the dash panel. One contains the fan, evaporator (cooling coil), air distribution ducting and related control doors. The other contains the heater core, as well as air inlet ducting and control doors. The evaporator unit also contains a drain pan and tubing to carry away moisture that condenses on the evaporator coils as warm, moist outside air passes through it.
The components and elements in the engine and passenger compartments are part of one or more of four cooling-heating subsystems. The subsystems are:
The principal components in this system are the compressor, the condenser coil, the receiver-drier-strainer cylinder, an expansion valve and the evaporator coil.
The refrigerant circulates through these components, extracting heat from the air passing through the evaporator and rejecting it to outside air passing through the condenser.
The compressor pumps the refrigerant from the evaporator to the condenser. The receiver-drier-strainer stores the refrigerant until needed by the evaporator and removes any foreign particles or water that may be in the system. The expansion valve reduces the temperature and the pressure of the refrigerant before it enters the evaporator.
The compressor is a two-cylinder, "V"-type unit with a displacement of 9.45 cubic inches. It has mufflers in both suction and discharge lines to suppress gas pulsation noises.
The condenser is of conventional fin and tube construction. Both fins and tubes are made of aluminum.
The evaporator is also of fin and tube construction, but only the fins are aluminum. The tubes are copper.
The expansion valve is externally equalized. By sensing compressor suction line temperature and pressure, the valve regulates refrigerant flow rate so that the gas leaving the evaporator is superheated about 10 degrees F.
Although this subsystem is called a hot water circuit, the coolant is actually an anti-freeze mixture of water and ethylene glycol.
In the Dart air conditioning system, a flow shut-off valve is placed in the coolant line from the engine to the heater core. It closes off coolant flow when the air conditioning system is operated -- either MAX A/C or A/C.
With HEAT or DEF selections, the valve is open and permits continuous flow in the hot water circuit.
Because the return line from the heater core is connected directly to the water pump, there is flow through the core even when the cooling system thermostat is closed. The thermostat is fully open when engine coolant temperature is 180 degrees F.
The portion of the inlet duct system built into the car body includes the air inlet grille at the base of the windshield and the plenum chamber formed by cowl and dash sheet metal.
The right ventilator, an integral part of the passenger compartment unit, is the other part of the air inlet ducting. A door inside the ventilator shuts off the fresh air when the OFF or MAX A/C pushbutton is depressed.
For MAX A/C, a door between the heater core and the fan opens to let in air from inside the car. This door, together with the cooling air circuit beyond the fan, provides the only recirculated air path.
Between the fan and the air outlets are two air control doors that determine air routing.
The first is a heat/cold door with two positions. In the cool position, it closes off air to the heating and defrosting outlets and directs all air through the evaporator to the cooling air outlets. In the heat position, all air is directed to a two-position heat/defrost door, and then to the heating and defrosting air outlets.
When this second door is in the heat position, most of the air is directed to the floor. A small amount is allowed to bleed into the defrost position[. When this second door is in the defrost position], most of the air goes to the defroster grilles with a small amount going to the heating outlets.
Control System
Air control door positions, and the operation of fan and compressor, are determined by pushbutton selection. The following chart identifies the air control doors and components governed by pushbutton selections and shows how they are affected.
| Pushbutton Selection | OFF | MAX A/C | A/C | HEAT | DEF | |
|---|---|---|---|---|---|---|
| Air Control Door |
Fresh Air Door | Closed |
Open |
|||
| Recirculating Air Door | Open |
Closed |
||||
| Heat/Cool Air Door | Cool |
Heat |
||||
| Heat Defrost Air Door | Heat |
Defrost |
||||
Fan ON/OFF Switch |
Off |
On |
||||
Compressor Clutch ON/OFF Switch |
Off |
On |
Off |
|||
Hot Water Shut-Off Valve |
Closed |
Open |
||||
The vacuum part of the unit switches engine vacuum to actuators that operate the air control doors. Each actuator is linked mechanically to the air door it controls.
The hot water shut-off valve is operated by a vacuum actuator that is in parallel with the heat/cool air door actuator. Thus, whenever this door is in the cool position, the valve is closed. Whenever the door is in the heat position, the valve is open.
Blower speed is determined by three coiled wire resistors in series with the blower motor winding. Two of them are switched in or out of the circuit by the fan toggle switch on the instrument panel. The third resistor is switched out of the circuit when the fresh-air door closes, giving higher blower speeds on the MAX A/C selection.
Temperature control is achieved by intermittent operation of the compressor in cooling selections, and by mixing heated and unheated air in heating selections. In both cases, the temperature is determined by the position of the lever on the instrument panel.
The temperature control device for cooling is a thermostatically actuated, electrical switch that can be adjusted to function at different temperatures. Temperature for heating selections is controlled by a variable position door that divides incoming fresh air so that some passes through the heater core and some bypasses it to go directly to the fan.
The temperature control lever is mechanically linked to the door by a flexible cable. A second flexible cable connects the door to the temperature-sensitive electrical switch. Thus, the lever varies door position and switch setting simultaneously.
However, the switch is not effective when in a heating selection because the compressor drive electrical circuit is inactive, and the door is ineffective when in a cooling situation because there is no fluid flow in the heater core.
The variable position door that acts as the temperature control device for heating is located between the fresh air inlet door and the fan. Its position determines the quantities of heated and unheated air that merge at fan inlet. It can be varied from a total heating (hot) position to a total bypass (cold) position.
The temperature-sensitive electrical switch that acts as the temperature control device for cooling is mounted on the evaporator unit. It has a thermal sensing element located between the fins of the evaporator. It also has an adjustable set of contact points that open and close in response to the temperature changes detected by the sensing element.
When the evaporator temperature falls below the level determined by the control lever positon, the contact points open and break the electrical circuit to the clutch. This disengages the compressor unit until the temperature again rises above the selected level and the contact points close.
Thus, by thermostatic action, the compressor is switched alternately on and off to keep the air temperature within a few degrees of the selected level.
The left fresh air ventilator has no connection with the air conditioning. By simply unlatching the fresh air door and pulling it open, the driver gets a refreshing ventilating air flow.
The right fresh air ventilator is an integral part of the inlet ducting for the air conditioning. The front seat passenger gets ventilating air by unlatching the door and pulling it open.
Ventilating air is supplied only when the car is moving and the ventilators should be used only when the OFF button is pushed in.
In addition, air-conditioned cars with either of the two six-cylinder engines have a 35-ampere alternator instead of the standard 30-amp unit. The 35-amp alternator is standard on all V-8 models.
Larger 7.00 x 13 tires, which are standard for all Darts with a V-8 engine, are installed on all air-conditioned six-cylinder models.
Tinted glass is also installed on all air-conditioned cars unless a customer specifically indicates he does not want it. Tinted glass is strongly recommended because it reduces the heat caused by exposure to the sun.
Air Conditioning System Specifications and Data
| COMPRESSOR | |
|---|---|
| Type | 2-cylinder V-type |
| Designation | V-2 |
| Make | Chrysler Airtemp |
| Part No. | 2532160 |
| Displacement | 9.45 cu. in. |
| Drive | Magnetic clutch belt-driven |
| Drive Ratio - Compressor to Engine RPM | Six-cylinder engines - 1.08 : 1 V-8 engines - 1.12 : 1 |
| CONDENSER | |
| Type | Fin and tube |
| Material | Aluminum fins, aluminum tubes |
| Size, in. | 1-1/4 x 16-1/2 x 19-3/4 |
| EVAPORATOR | |
| Type | Fin and tube |
| Material | Aluminum fins, copper tubes |
| Size, in. | 2-1/2 x 6-3/16 x 11 |
| REFRIGERANT | |
| Type | Dichlorodifluoromethant (Refrigerant 12) |
| BLOWER | |
| Fan - type | Forward curved blade; centrifugal |
| Fan - size | 5-19/32 in. diameter x 2 in. wide |
| Motor - type | Fractional horsepower, series wound dc |
| AIR FLOW AND FAN SPEED | ||||
|---|---|---|---|---|
| Cubic feet per minute at revolutions per minute (CFM @ RPM) in still air, standard atmosphere. | ||||
| Low Fan | Medium Fan | High Fan | ||
| MAX A/C | Temperature control lever at cool position |
100 @ 1550 | 150 @ 2350 | 175 @ 2780 |
| A/C | 75 @ 1320 | 125 @ 2120 | 150 @ 2500 | |
| Engine | Six-Cylinder - 170 & 225 Cubic Inches |
V-8 - 273-Cubic Inch With 2 or 4-BBl Carb. |
|||
|---|---|---|---|---|---|
| No A/C | With A/C | No A/C | With A/C | ||
| Radiator | Type | Tube and Spacer |
|||
| Width (in.) | 19 |
22 |
|||
| Height (in.) | 17-1/8 |
||||
| Thickness (in.) | 1-1/4 |
1-1/2 |
1-1/4 |
2 |
|
| Pressure Cap - Relief Pressure (psi) | 14 |
16 |
14 |
16 |
|
| Fan | Diameter (in.) | 16 |
17 |
17 |
17 |
| No. of Blades | 4 |
6 |
6 |
7 |
|
| Blade Pitch (in.) | 1-1/2 |
1-1/4 |
2 |
2-1/4 |
|
| Drive Ratio (Fan and Water Pump to Crankshaft RPM) |
1.07 : 1 |
1.10 : 1 |
0.95 : 1 |
1.30 : 1 |
|
| Type of Drive | Solid |
Viscous with |
|||
| Fan Shroud | Usage and Type | None |
Box |
None |
Box |
| Water Pump | Type | Centrifugal |
|||
| Impeller - No. of Blades | 6 |
10 |
6 |
||
| Blade Diameter (in.) | 3.5 |
4.2 |
3.5 |
||
| Hood to Yoke Seals | None |
Standard |
|||