Constant Velocity Carburetor Explained

The

carburetor

throat is properly known as a Venturi, which is just a $64 word for a tapering tube. Our carbohydrates are known as variable Venturi. The Venturi effect states that when we move a fluid through a constriction, the

velocity

increases and the pressure decreases in the narrow part. section, you may also have heard the term CV in relation to the style of carbohydrates we have. CV means

constant

speed, not

constant

vacuum, as it is commonly and erroneously called. The fact is that vacuum changes all the time and you'll soon understand why, while Mr. Venturi was worried about plumbing.

A guy named Daniel Bernui focused his genius on gases. The Bruli effect, as it is known, is the math and physics behind why airplane wings develop lift. We take our understanding of the Bruli effect and put it to work on our carbs. This is how it works it all starts inside the engine when a piston moves down it draws air through the Venturi. It is important to recognize that regardless of engine speed, each downstroke can only extract a fixed amount of air. The volume is obviously governed by the displacement but also by the The cams that tell the valves how much to open and how long to stay open, the speed of the engine, while the volume per event is fixed, give the airstream its speed. , so in reality the air that is drawn through the Venturi is not a smooth stream, but rather enters in a very irregular and abrupt pulse.

We refer to each entry event as a signal because, just like a sound or a Radio wave has frequency and amplitude. There's a third unique characteristic of air that has to do with it being both compressible and stretchable, but that part of the puzzle falls under how the Jets do their job and will only muddy the waters if they drag us in too soon, so with the throttle closed we have negligible volume but we have vacuum in the engine so we place the pilot hole well in front of the throttle plate to use it at idle, excuse me, bruli is almost out of the picture at this point, however, in idle, the throttle plate is actually not tightly closed, but open only to break, according to beri, we have the maximum constriction at the edge. of the throttle plate, although the volume is very small, we have the highest speed and therefore the lowest pressure, we locate the bypass holes here so that they can contribute their part to the idle and idle as the throttle is opened, the engine accelerates and the speed increases in the Venturi noticeably more at the constriction point this creates a vacuum that is shared with the inside of the lid through the lift vents of the slide, the low ambient Resulting pressure here pulls the slide upwards as the slide rises the size of the constriction increases according to berui this decreases both speed and vacuum until a magic point is reached where the forces balance, so that in reality the slide is like the wing of an airplane held at the point of balance between gravity and user-adjustable airflow, which in turn creates changing degrees of lift on demand the slide goes up the speed goes down the low slip speed increases as we change the size of the constriction the speed through the constriction, which is where we locate our main jets, remains at a constant speed regardless of engine speed, hence the In terms of ventur variable and constant speed, the two things that constantly change are vacuum and air volume.

In the next segment we will explore those variables in greater depth.