Two-stage fuel injection cold start method and apparatus for carrying out same

Claim 1

Apparatus for reducing exhaust and inoperative pollutants produced by a high speed injection system for a spark-ignition internal combustion engine of the type including a rotating shaft, one or more cylinders each having an injection valve responsive to a control signal for injecting and mixing a predetermined quantity of full-range fuel with air to form a combustible mixture for delivery to said each cylinder of said engine through an intake valve, computing means including synchronization means, condition means and cold start circuit means for controlling and generating first and second control signals as function of one or more engine operating parameters, and additional cold start valve means responsive to said second control signals as well as to signals indicative of engine temperature below a selected set point level adapted to control injection of additional cold start fuel into said each corresponding cylinder through said intake valve during cold starting of said engine, said synchronizing means of said computing means being operatively connected to each of said injection valves for synchronizing operation thereof as a function of predetermined angular shaft position by generating a series of start signals for each of said control signals at said injector valves, said condition means being responsive to each of said start signals as well as to signals indicative of other operating parameters, for controlling the duration of said first control signal at said each of said injection valves, and said separate cold start circuit means being connected to said additional cold start valve means for generating said second control signals, as a function of said engine temperature level, comprising: i. a cannister assembly containing adsorbent material (a) capable of selectively adsorbing high molecular weight constitutents of said fuel-range fuel at cold start while eluting substantially unimpeded a cold start fuel effluent composed essentially of only low molecular weight constituents as well as (b) capable of selectively absorbing vapor constituents of said full-range fuel during an inoperative state of said engine, ii. valve and conduit network means attached between said cannister assembly, a reservoir means for said full-range fuel and said injector valves for providing selective flow of said fuel including said cold start fuel between said cannister assembly, said reservoir means, each of said injector valves, and said additional cold start valve means, said network means including a first plurality of conduit and valve means including first and second valve means controlling flow relative to said cannister assembly so as to allow, in a first operating state, flow of said full-range fuel from said reservoir means to said cannister assembly and flow of said cold start fuel effluent in parallel first and second streams from said cannister assembly to said each injector valve and said additional cold start valve means, respectively, to provide for rapid starting of said engine without producing excessive exhaust pollutants and, in a second operating state, full-range fuel to flow from said reservoir means to said each injector valve in sequence thereby bypassing said cannister assembly and said additional cold start valve means after said engine is in a normal running condition, said network means also including a second plurality of conduit means including a third valve means operatively connected between said cannister assembly and said fuel reservoir means for selectively conveying vapor evaporative emissions of said fuel within said fuel reservoir to said cannister assembly when said engine is in said inoperative state, iii. control means operatively connected to said first second and third valve means of said valve and conduit network for changing operation states so as to direct fuel flow relative to said cannister assembly, said reservoir, said each of said injector valves and said additional cold start valve means as a function of one or more engine operating parameters.