Friday 20 December 2013

Automobile air conditioning

Automobile air conditioning systems cool the occupants of a vehicle in hot weather, and have come into wide use from the late twentieth century. air conditioners use significant power; on the other hand the drag of a car with closed windows is less than if the windows are open tocool the occupants. There has been much debate on the effect of air conditioning on the fuel efficiency of a vehicle. Factors such as wind resistance, aerodynamics and engine power and weight have to be factored into finding the true variance between using the air conditioning system and not using it when estimating the actual fuel mileage. Other factors on the impact on the engine and an overall engine heat increase can have an impact on the cooling system of the vehicle.

History

A company in New York City in the United States, first offered installation of air conditioning for cars in 1933. Most of their customers operated limousines and luxury cars.
The packard motor car company was the first automobile manufacturer to offer an air conditioning unit into its cars, beginning in 1939. These air conditioners were manufactured by Bishop and Babcock Co, of Cleveland Ohio. The "Bishop and Babcock Weather Conditioner" also incorporated a heater. Cars ordered with the new "Weather Conditioner" were shipped from Packard's East Grand Boulevard facility to the B&B factory where the conversion was performed. Once complete, the car was shipped to a local dealer where the customer would take delivery.
There were many reasons why this early air conditioner unit was unsuccessful: 1) The main evaporator and blower system took up half of the trunk space. (This problem would go away as trunks became larger in the post-war period.) 2) The system was less efficient than those that would follow in the post-war years. 3) It had no temperature thermostat or shut-off mechanism other than switching the blower off. (Cold air would still enter the car with any movement as the drive belt was continuously connected to the compressor--later systems would use electrically operated clutches to remedy this problem.) 4) The several feet of plumbing going back and forth between the engine compartment and trunk proved unreliable in service. 5) Finally, the biggest reason this early system failed was that it cost US $274.00 (equivalent to $4,544 today) an enormous amount of money in post-depression/pre-war America.
Packard fully warranted and supported this conversion, and marketed it well. However, given the limitations above, it was unsuccessful. Subsequently, the option was discontinued after 1941.

Chrysler Airtemp

The 1953 chrysler imperial was the first production car in twelve years to actually have automobile air conditioning, following tentative experiments by packard in 1940 and cadillac in 1941. walter p. chrysler had seen to the invention of  airtemp air conditioning back in the 1930s for the chrysler building, and had ostensibly offered it on cars in 1941-42, and again in 1951-52, but none are known to have been sold in the latter form until the 1953 model year. In actually installing optional Airtemp air conditioning units to its Imperials in 1953, chrysler beat Cadillac, buick and old mobile which added air conditioning as an option in the 1953 model year.
Airtemp was more sophisticated and efficient than the complicated rival air conditioners of 1953. It recirculated, rather than merely cooled, the air inside the vehicle, and it was also the highest capacity unit available on an automobile. It was also simple to operate, with a single switch on the dashboard marked with low, medium, and high positions, which the driver selected as desired. The system was capable of cooling a Chrysler from 120 degrees to 85 degrees in about two minutes, and of completely eliminating humidity, dust, pollen and tobacco smoke at the same time. Since it relied on fresh air, and drew in sixty percent more of it than any contemporary system, Airtemp avoided the staleness associated with automotive air conditioning at the time. It was silent and unobtrusive. Instead of plastic tubes mounted on the package shelf as on GM and on other cars, small ducts directed cool air toward the ceiling of the car where it filtered down around the passengers instead of blowing directly on them, a feature that modern cars have lost.