Pneumatic rpm regulator for fuel injection pumps

Claim 1

In a pneumatic rpm regulator associated with a fuel injection pump of an internal combustion engine, said pump having a fuel rack, said regulator being of the known type that includes (a) a vacuum chamber, (b) an additional chamber, (c) means effecting communication between said additional chamber and the ambient atmosphere, (d) a diaphragm separating said chambers from one another and (e) means connecting said diaphragm to said fuel rack for causing displacement of the latter upon deflection of said diaphragm, the improvement comprising: A. means defining a throttle bore in said additional chamber, said throttle bore maintaining a continuous communication between said additional chamber and the ambient atmosphere and B. a check valve provided for in said additional chamber and designed to open inwardly, said check valve, when open, maintaining communication between said additional chamber and the ambient atmosphere; said throttle bore and said check valve constituting said means effecting communication between said additional chamber and the ambient atmosphere, such that during sudden engine acceleration said throttle bore causes a delay in the response of said fuel rack due to the throttling effect of the air from said additional chamber through said throttle bore to the ambient atmosphere, while during engine deceleration said check valve ensures nondelayed response of said fuel rack due to the passage of ambient air through said check valve and into said additional chamber.