Abstract:
Vanes in an air duct, independently controlled, one by the engine operator and others by environmental factors, generate vortices determining the speed of a turbine and thereby the flow of fuel through a fuel meter and fuel valves into prechambers for vaporization and mixing with spiraling air.

Description:
BRIEF SUMMARY OF THE INVENTION 
     It is the object of this invention to further pursue the four goals of the continuing development of Otto cycle engines, performance, fuel economy, driveability and low emmissions, with improved fuel control and combustion, using simple hardware with few precision parts, compatible with currently produced engine types and producible in existing facilities without large investments for tooling. 
     To accurately meter the fuel flow it is proposed to generate air vortices in the engine air duct with several separate aerodynamic vanes, one reacting to power needs and others to environmental factors, and thereby control the speed of a propeller turbine and of a coupled fuel meter regulating the fuel flow from a vented floatbowl to vented fuel valves, from which the fuel is injected in cyclical increments into prechambers through which during each intake stroke air flows in spirals which are formed with ports tangential to the circular prechamber wall. Spiral flows rotating in opposing directions during each compression stroke cause turbulence for vaporization and mixing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a semi-schematic view of a fuel control system in an internal combustion engine; 
     FIG. 2 is a functional diagram of a fuel control system showing the relation of its parts. 
    
    
     Application of the invention to reciprocating Otto cycle engines is shown in FIG. 1. Air enters through filter 1 and flows through duct 2 into manifold 3 after passing by aerodynamic vanes 4, 5 and 30, propeller turbine 6 and throttle 7. The turbine is forced to respond to changes of air mass flow and operational needs with air vortices generated in the duct by said vanes. Fuel flows from float bowl 8 to fuel meter 9 which is mechanically coupled to said turbine. Engine power is controlled with rod 10, linked to vane 4 with lever 4b, spring 31 and cam 11 and to said throttle with rod 12. The cam is shaped to cause enrichment of the mixture during idle and at higher power levels. Vane 5 is positioned with bimetallic spring 13 and barometer gauge 14, both exposed to ambient air. Vane 30, located behind vane 4, is positioned with a bimetallic spring exposed to engine heat or actuated manually during engine warm-up. 
     Fuel manifold or rail 15 connects said fuel meter with flow divider 16 and with a fuel valve 17 at each cylinder. Incoming fuel is accumulated in the vented valve body during compression, expansion and exhaust strokes. Plunger 18 closes fuel inlet 17a and venting orifice 17b and then expulses the fuel increment and air enclosed in the valve body through check valve 17c and drilling or tube 19 to prechamber 20. A part of the intake valve train, such as spring retainer 21 actuates the fuel valve and times increment delivery. The space under valve cover 22 is at all times vented to air filter 1 and float bowl 8. As air flows radially from the open intake valve 24 some enters through port 25 into said prechamber, spirals through it and out through port 26 which is displaced from port 25 and shielded from the intake air flow with lip 26a. Mixed with vaporizing fuel and very turbulent after compression the charge in the prechamber is ignited with spark plug 27. Said ports direct precombustion flames and products into the main charge. Shown also in FIG. 1 is an alternate way of fuel delivery with the increments squirted through tube 28 to one side of said intake valve and channeled in part through port 25 into the prechamber. 
     DETAILED DESCRIPTION 
     A metering unit, combining float bowl, fuel meter, vanes with sensing actuators, turbine, throttle and air duct, can be designed for any air flow direction and is compatible with convential air filters, manifolds, fuel filters and tank pumps. 
     A multi-bladed propeller is the preferred embodiment of the turbine. Its speed increases linearly with the volume flow rate of air. Low moment of inertia and friction assure fast response to air velocity changes and limit speed errors. Propeller speed range and blade area and incidence angle must be compatible with the selected type of fuel meter, preferably a small gear type meter coaxially connected to the turbine. With the fuel flowing under gravity from a float bowl to fuel meter and fuel valves the head pressure compensates for some friction losses. The turbine spin rate is governed with movable vanes, placed ahead of the propeller, by generating vortices which force the turbine to respond to changes in air mass flow rate instead of volume rate and also to variations in environmental and operational conditions requiring different air/fuel ratios. The spin rate depends on air speed, on the incidence angle of the turbine blades and on the helix angle of a vortex. Any small number of vanes can be employed and combined with sensing actuators in different ways. A three vane system is the preferred embodiment. A third vane, part 30 in FIG. 1, substantially of the same form and construction as vanes 4 and 5 and located opposite of vane 4 behind shaft 6a of turbine 6 is deflected to increase turbine speed during cold starts with a bimetal spring exposed to engine temperature or with a manual choke. Vane 5 is rotated to decrease turbine speed at lower air densities with bimetallic spring 13 reacting to changes of air temperature, attached to shaft 5a and to a barometric gauge 14, preferably of the aneroid type, attached to lug 2b of duct 2, both exposed to air flowing into or through the duct; the latter position is suitable for supercharged engines. Vane 4 is rotated to cause an increase of the turbine speed when lower air/fuel ratios are needed at higher power levels and during idle. This vane is linked with lever 7b and shaft 7a to throttle plate 7 which serves to control power at the lower levels. After reaching a stop on crossarm 2a only vane 4 continues to rotate to increase fuel flow. It can be deflected also to slow or stop the turbine during vehicle deceleration and downhill travel. The vanes can preferably be placed in a spherical zone of the duct to minimize gap losses and increase air vorticity thereby reducing needed vane area. Aerodynamic balancing of a vane minimizes actuation forces and thus actuator size, which is achieved by locating the rotation axis at 1/4 chord of the vane. 
     The air manifold requires no heating equipment. The fuel manifold consists of main line 15a, flow divider 16 and individual lines or hoses 15b to each cylinder. Their flow resistances can be kept very small and can furthermore be matched with those of the air manifold branches. Fuel flowing through the manifold must, in contrast to known fuel injection methods, not overcome differential pressures because the air pressures in the float bowl and the fuel valves are equalized through vent lines connecting orifices 17b in the fuel valves with vent 8a of the floatbowl which is also open to ambient air, or, the preferred embodiment, by venting each orifice directly into the valve chamber under cover 22 which is connected through vent tube 23 and air filter 1 with vent 8a. Without venting, large pressure differentials across the fuelmeter could cause unacceptable errors in the fuel flow rate from leakage and also from power extraction from the turbine affecting its speed. 
     Fuel valves 17, able to receive the varying flow in a vented space and deliver it in increments to the cylinders, in a liquid stream through a checkvalve to one side of the intake valve head or, the preferred method, directly into a prechamber. 
     This cavity, preferably cast into the head, contains a small part of the compression volume. Circular in cross-section it has two or more ports which are tangential to the circular prechamber wall laterally and angularly offset from each other to direct the flow to spiral through the prechamber. One port, located adjacent to the intake valve 24, receives a small part of the air flowing radially from the intake valve, which then flows in a spiral through the cavity and downwards out through one or more ports. The spiral flow pattern depends on the cavity shape, on the geometric relation and size of the ports and their placement relative to the intake valve. Air mixes with exhaust residuals and with fuel flowing into the prechamber directly or through its inlet port, The fuel vaporizes in the hot cavity and a relatively rich mixture remains in it at the end of the intake stroke. During compression turbulence is generated by internally opposing flows entering through both ports, which serves to complete mixing and vaporization. Precombustion flames and products emitting out of all ports are directed into and mainly to the middle of the turbulent and lean main charge. The jet pattern depends on the geometric orientation of the prechamber to the cylinder and the relation and relative size of the ports. 
     Ways to produce parts for the disclosed fuel control system are apparent to persons skilled in the pertaining art. Many parts of known fuel control systems including those for the limitation of emissions are eliminated and fewer precision parts are needed which reduces costs and simplifies servicing.