Vacuum Switching Valve
Today’s automobiles are essentially all run by computer. This can be a very useful way to run a car. Computers can help technicians diagnose problems in a car. They can also help make sure that the car is running at peak performance. They can even let the driver know just exactly how many miles per gallon he or she is getting as the car is motoring down the road. (In today’s extremely environmentally conscious world, where gas prices are soaring and geopolitical instability ensures we never know when the next gas price spike is going to occur), this type of car computer can be increasingly important and helpful.
But it’s true, of course, that cars were around long before what we think of as modern day computers. And car can be said to have run just as well back then and they do today. How can that be? Well, the original inventors and improvers of automobiles used the laws of physics and very complex mechanical knowledge in order to create cars that ran in ingenious ways. One of these inventions that helped early cars run just as good as modern cars was the vacuum switching valve.
Before engine computers were even a twinkle in some automotive technician’s eye, engine vacuum was an integral part of a car’s operation. These engine vacuums were controlled by something called vacuum switching valves. These vacuum switching valves were used to regulate the flow of vacuum. They were controlled by temperature and were used to operate vacuum motors, other vacuum switches, and other devices.
The reason that vacuum switching valves were so effective is that they helped to harness something that was already present in the car’s engine. A car engine already produces almost 20 inches (or 51 cm) of vacuum. Smart auto technicians figured out how to harness this produced vacuum for many handy uses. They were even able to harness vacuum in order to obtain information on engine load.
There is not just one type of vacuum switching valve, of course. In fact, there are several, and all can be useful in harnessing vacuum power to help run a car or gather information about its engine load. For example, the “check valve” is a vacuum switching valve that only allows the vacuum signal to move in one direction. Because the check valve only allows vacuum signals to move in one direction it is often used along with vacuum reservoirs.
The “delay valve” (sometimes called a “vacuum delay valve”) on the other hand, is a vacuum switching valve that features a small orifice that allows it to delay a vacuum signal (hence it’s name.) The delay valve types of vacuum switching valves are commonly used in automobiles to alter the behavior of an existing vacuum signal. Delay valves are usually color coded to their function. For ease of use, delay vacuum switching valves are usually color coded, with one color for each use.
Another type of vacuum switching valve is the coolant temperature override. This type of valve can have several different names, including temperature vacuum switch (TVS) or thermal vacuum valve (TVV). This type of vacuum switching valve measures coolant temperature, most commonly from a passage in the car’s intake manifold. These types of vacuum switching valves came into common usage in the 1960’s where they were used to promote cooler idling in automobiles. They commonly have between two and five ports.
Though vacuum switching valves may not be as commonly used as they once were, it is clear that they were a very important part of our automobile history.