Читать книгу How to Repair Automotive Air-Conditioning & Heating Systems - Jerry Clemons - Страница 7

CHAPTER 1

INTRODUCTION AND HISTORY

Automobiles have been around since the late 1800s, and changes have come along to improve them in every imaginable way. The vehicles from the 1800s did not have an enclosed cab to protect the occupants from the elements.

History of Cabin Heating Systems

Closed-body cars first appeared in the early 1900s, and the occupants used gas lamps and gas burners to provide heat. These heating techniques were the same methods that horse-drawn carriages were using. As time passed by, manufacturers used engine exhaust heat as well as hot air off of the engine to produce a little heat for the cabin and its occupants.

Car manufacturers began using heated engine coolant in the 1930s, which was a more effective method to provide comfort. General Motors and the Nash brand were among the first companies to use heater cores to provide heat for the cabin of the vehicle. Another milestone that General Motors was involved in was the heated seats that were available on a few models. Development of heating systems on a wide sector of the market was somewhat slow because it was the late 1950s when most models had heating systems. By the 1960s, heating systems were standard equipment across most major car brands.

The heater hoses route the engine coolant into the heater core of this 1969 Chevrolet Camaro.

The climate control head on this 1969 Camaro has settings for blower speed, air temperature, and defrost. This system uses cables to move the doors on the duct box.

History of Air-Conditioning Systems

Keeping the driver and passengers comfortable in hot weather was also a challenge for car manufacturers. Techniques used in the early history of the car business included canvas covers, vent windows, and crank-style windows.

Providing shade to keep direct sunlight off of the occupants was an improvement over open-air vehicles. In addition, providing windows that could be positioned to provide increased velocity of the air provided more cooling capacity for the cabin.

Air-conditioning systems that used a pressurized refrigerant first appeared in the early 1930s. The Packard Motor Car Company was the first manufacturer to offer air-conditioning as an option around 1939. The system used by Packard was manufactured by Bishop and Babcock and was called the weather conditioner. This air-conditioning system was mounted in the trunk and involved a lot of plumbing and piping, which was a disadvantage because there were many places that could develop a leak. This system used a compressor that ran at all times and did not have any temperature adjustments. The $274 price for this system made it a very expensive option for that time period.

The windshield on this 1936 Rolls-Royce folds forward to allow increased airflow into the cabin to help keep the occupants comfortable in hot weather. This vehicle also has side windows and vent windows that operate with a crank.

This two-door 1957 Chevrolet Bel Air has side windows and vent windows that operate with a window crank arm. The vent window was a popular option that caused a strong airflow when it was opened up.

The window crank arms and door handle are within easy reach for the passenger of this two-door 1957 Chevrolet Bel Air.

Chrysler and General Motors began offering air-conditioning as an option in the early 1950s. In 1954, the Nash Ambassador used a system called the “weather eye,” which was the first fully integrated climate control system with air-conditioning. It included dash controls and an air-conditioning compressor with a clutch that could turn on and off as needed.

By the 1960s, air-conditioning was growing in popularity and market share. In 1969, 54 percent of cars sold in the United States were equipped with air-conditioning. Characteristics of cars from this era were the large compressors and large quantities of refrigerant used to make them work. A good sales pitch for this popular system was that it would increase resale value on the vehicle. As time passed, more and more vehicles were sold with air-conditioning as standard equipment.

Evolution of Heating and Air-Conditioning Systems

Cabin comfort in automobiles has seen many changes in the last 100 years. The industry has gone from not having cabin heat or an air-conditioning system to both becoming standard equipment. Many other advances have become common on cars and trucks as well. Some advancements that are available on modern cars and trucks include dual zone systems, rear heat and air systems, automatic temperature control systems, heated and cooled seats, and remote starting systems.

Dual zone climate control systems allow the driver and the passenger to have different air temperatures delivered to each side of the car. These systems are typically available on upscale vehicles and are made possible by having a more complex duct box system that has separate blend doors for each side of the vehicle. The drawback of these systems is that with more complexity in the system, more potential problems can occur when the vehicle begins to get older and in the higher-mileage category.

This dual zone climate control head allows the driver and the passenger to choose different temperature settings for each side of the vehicle. This control head also has the switches for the heated seats for the driver and the passenger.

The heat and air-conditioning controls are located at the roof area within easy reach of those in the second-row seats on the driver’s side. This control allows the blower speed, the temperature, and the mode to be chosen.

Many larger vehicles are equipped with rear heat and air systems that provide heat and air-conditioning directly to the rear section of the cabin. Having the added capacity to heat and cool the rear of a larger vehicle provides much improved comfort for the passengers of these vehicles. These systems require hoses and lines for heated coolant as well as pressurized refrigerant to be routed to the back section of the vehicle. This requires increased capacity for both the cooling system as well as the refrigeration system. In addition, these systems have more serviceable parts that must be operational as well as more potential leak locations for the coolant and refrigerant.

Automatic temperature control is another convenient option that is available on many modern vehicles. These advanced systems incorporate many sensors and computers to automatically control the temperature to the desired level. When these systems are in automatic mode, the operator selects the desired cabin temperature and the system works to move the cabin temperature to that level. Many of these systems are also equipped with dual zone capabilities, as mentioned previously.

Heated and cooled seats have become very popular in modern upscale vehicles. This added capacity to keep the occupants comfortable is a great advancement that is popular with consumers. Heated seats have been available for many years, but cooled seats have only been available for a few years.

Remote start systems have become a popular option in recent years. These systems are incorporated into the keyless remote systems and allow the user to start the vehicle by using the remote transmitter. Being able to start the engine with a remote control allows the heater or air-conditioning system to begin working before the driver enters the vehicle. This process allows the operator and passengers to enter a climate-controlled vehicle rather than having to wait for the system to get to the efficient zone after entering the unit.

This control head features automatic temperature control, dual zone, and rear defogger controls. Most vehicles with automatic temperature control also allow the operator to manually pick the air distribution point, blower speed, and air temperature.

The remote control for the door locks also features a button for the remote start function for this vehicle. Most vehicles with factory remote start require a sequence of buttons to be pressed in order to activate the function, which reduces the chances of accidentally starting the vehicle.

The rest of this book will provide information on how the air-conditioning and heating systems operate as well as how to diagnose and repair many of the common problems that could occur with these systems.