Abstract:
This invention relates to a method of indicating changes in the rate of fuel consumption in internal combustion engines from a predetermined rate utilizing as a basis a predetermined vacuum in the engine manifold and using variations from such vacuum to operate a switch mechanism in at least one electrical circuit for a display means which indicates when the vacuum is above or below or at the predetermined level.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method of, and a device for, indicating rates of fuel consumption in internal combustion engines. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is the object of this invention to provide a simple method of and a device for indicating the changes in the rate of fuel comsumption from a predetermined rate. 
     In accordance with this invention a method of indicating changes in the rate of fuel consumption in internal combustion engines from a predetermined rate comprises using the vacuum in a manifold of the engine to operate, at a predetermined vacuum, the switch mechanism of at least one electrical circuit for a display means which indicates when the vacuum is above and below a predetermined level. 
     Further features of this aspect of the invention provide for said display means to emit light of changing colour when the vacuum varies above and below said predetermined level, and for said display means to include two electrical circuits each of which includes a light emitting diode. 
     The invention also provides a device for indicating changes in the rate of fuel consumptions in internal combustion engines from a predetermined rate comprising a vacuum-operated switch mechanism connected to at least one electrical circuit of a display means indicating when the vacuum is above and below a predetermined level. 
     Further features of this aspect of the invention provide for two independent electrical circuits each including a light emitting diode; the switch mechanism is adapted to activate the one circuit below a first predetermined level and to activate the other circuit above a second predetermined level such that both circuits are activated between the two levels. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Various other objects, features, and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description when considered in connection with the accompanying drawing wherein: 
     The sole FIGURE is a schematic electrical circuit diagram of electrical apparatus assembled in accordance with the present invention so as to carry out the method thereof, and wherein the vacuum-operated switch mechanism thereof is shown in cross-section. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In this embodiment of the invention a device for indicating changes in the rate of fuel consumption of an internal combustion engine comprises a vacuum operated switch mechanism 1 including two sets of contact points 2 &amp; 3. The contact points are each connected to a separate circuit of a display means generally indicated at 4. 
     Included in the display means are two circuits 5 and 6, the one circuit 5 including a red light emitting diode 7 and the other circuit 6 including a green light emitting diode 8. The electrical power supply for the circuits includes a 12 volt d.c. power supply and resistors 9, the resistors 9 being in series between the diodes 7 and 8 and the positive terminal of the power supply. The diodes are then grounded to the negative terminal of the supply. 
     As may be seen from the drawing and as will become more apparent hereinafter, both circuits are adapted to be alternatively closed or simultaneously opened at predetermined vacuum levels, and thus both diodes will accordingly limit or emit the light of their respective colours. The switch mechanism 1 is used to short out the power supply to the circuits 5 and 6 from points between the resistors 9 and the diodes 7 and 8. 
     In greater detail the switch mechanism 1 comprises a cylindrical housing 10. Within the housing 10 is a diaphragm 11 resting on a resilient elastomeric ring 12 which in turn rests on a base 13 of the housing 10. On each side of the diaphragm 11 is a conducting metal strip 14 and 15 as in a printed circuit board for example. 
     An adjustable contact pin 16 extends through the base 13 of the housing and terminates in a point just short of the metal strip 15, thus forming the set of electrical contacts 3. A similar contact pin 17 extends through the upper wall 18 and terminates in a point which is normally in contact with the metallic strip 14, thus forming the set of contact points 2. Both pins 16 and 17 are grounded to the negative terminal of the power supply. 
     Shorting wires 19 and 20 for both circuits extend through the wall 18 of the housing 10; the wire 19 for circuit 6 being connected to the metal strip 14 and the wire 20 for circuit 5 passing through a sealed hole 21 in the diaphragm and being connected to the metal strip 15. 
     The space between the diaphragm 11 and the base 13 is connected to a vacuum tube 22 which is adapted to be connected to an internal combustion engine inlet manifold (not shown); whereas the space between the diaphragm and the wall 18 is open to the atmosphere. 
     At low vacuum levels the switch mechanism is as shown in the FIGURE with contacts 2 closed and contacts 3 open, thus contacts 2 short out circuit 6 and its green light emitting diode 8 will not function. However, the diode 7 of circuit 5 will emit a red light. As the applied vacuum to the tube 22 is increased, the reduced pressure on the diaphragm 11 causes it to compress the resilient ring 12 and to open the set of contacts 2 thus causing the diode 8 to emit a green light. At this stage, both red and green lights are emitted by the respective diodes and are combined to present an effectively yellow light on the display. 
     Further increase of the vacuum causes further compression of the ring 12 until the set of contacts 3 are closed, thus shorting out circuit 5 and causing the red light emitting diode 7 to cease to function. At this stage only green light is emitted by the display 4. As both contact pins are adjustable the predetermined vacuum levels which the contacts operate may be varied. 
     It is to be appreciated that the rate of fuel consumption is proportional to the reduced pressure in an inlet manifold of an internal combustion engine so that the device, in operation, will give an indication to a person when the consumption rate is above or below the predetermined level. The display means thus emits a green light when the consumption rate is low, a red light when this rate is excessive, and a yellow light when the rate is moderate. 
     The device and its method of operation are simple and the invention provides useful means to enable a driver of a motor vehicle, for instance, to drive the vehicle economically. 
     Other embodiments are envisaged within the scope of the invention and include other switch mechanisms and display means.