Integral Bonnet Needle Valve

needle valve
A valve closed by a thin tapering part
A needle valve is a type of valve having a small port and a threaded, needle-shaped plunger. It allows precise regulation of flow, although it is generally only capable of relatively low flow rates.
Adjustment on a carburetor used to set proper fuel/air mixture. Some carburetors have separate needle adjustments for low and high throttle. Typically, turning the needle clockwise (screwing in) leans the mixture (less fuel), and vice versa.
This is used to tune the fuel to air mixture on the engine carburetor. On most engines, the needle is turned clockwise to lean the mixture, and counterclockwise to richen.

integral
A function satisfying a given differential equation
the result of a mathematical integration; F(x) is the integral of f(x) if dF/dx = f(x)
A function of which a given function is the derivative, i.e., which yields that function when differentiated, and which may express the area under the curve of a graph of the function
built-in: existing as an essential constituent or characteristic; "the Ptolemaic system with its built-in concept of periodicity"; "a constitutional inability to tell the truth"
constituting the undiminished entirety; lacking nothing essential especially not damaged; "a local motion keepeth bodies integral"- Bacon; "was able to keep the collection entire during his lifetime"; "fought to keep the union intact"

bonnet
a hat tied under the chin
dress in a bonnet
A soft round brimless hat like a beret, esp. as worn by men and boys in Scotland
A woman's or child's hat tied under the chin, typically with a brim framing the face
The ceremonial feathered headdress of an American Indian
hood: protective covering consisting of a metal part that covers the engine; "there are powerful engines under the hoods of new cars"; "the mechanic removed the cowling in order to repair the plane's engine"