Fuel additive injection device

A device for injecting a fuel additive into the intake system of an automotive engine, the amount of fuel additive injected being dependent upon engine load conditions, comprising in combination:

• a vacuum chamber, said chamber being adapted to be operatively connected to a source of vacuum in an intake manifold of said engine;
• a movable diaphragm, said diaphragm forming one wall of said chamber such that said diaphragm moves in response to changes in pressure in said chamber;
• a bias spring in said chamber urgining said diaphragm in one direction;
• a control rod connected to said diaphragm on the side thereof opposite said chamber;
• an adjustable inlet passage for supplying a fuel additive fluid;
• a pump for delivering said fuel additive under pressure;
• a flow control passage in fluid communication with said inlet passage for supplying additive into said intake system;
• a tapered valve seat formed within said flow control passage, said control rod extending through an aperture in said valve seat;
• a fixed valve control member coupled to said control rod and disposed relative to said valve seat to engage therewith and comprising a flared portion which uniformly increases in diameter in a direction away from said chamber to match the taper of said valve seat, wherein changes in pressure in said chamber move said control rod and said valve control member to control the flow of said additive through said flow control passage;
• a second flow control passage connected in series with said first-mentioned flow control passage and joined thereto by a mixing chamber;
• a second inlet passage connected to said second flow control passage for supplying a second fuel additive fluid;
• a second tapered valve seat formed within said second flow control passage;
• a second flared valve control member coupled to said control rod in series with said first flared control member and positioned in said mixing chamber relative said second valve seat;
• said first flared control member positioned in said mixing chamber in a back-to-back relationship with said second flared control member;
• wherein a decrease in pressure in said chamber decreases the flow of said first-mentioned fuel additive fluid while simultaneously increasing the flow of said second fuel additive fluid and an increase in pressure in said chamber increases the flow of said first-mentioned fuel additive fluid while simultaneously decreasing the flow of said second additive fluid.