Fuel injection system

Claim 2

A fuel injection system for a multi-cylinder internal combustion engine having an intake manifold, and an intake manifold branch passage leading from said intake manifold, said fuel injection system comprising, in combination, a fuel pump having a fuel outlet and driven by said engine for delivering pressurized fuel to said fuel outlet at a pressure substantially proportional to the engine speed, a fuel distributing pipe connected to said fuel pump, pressure regulating means connected to said fuel distributing pipe for regulating the pressure of said pressurized fuel in said fuel distributing pipe, said pressure regulating means having diaphragm means communicating with said intake manifold and responsive to an intake manifold vacuum to cause said pressure regulating means to regulate the pressure of said pressurized fuel in said fuel distributing pipe in dependence on the intake manifold vacuum, a fuel injection nozzle communicating with said fuel distributing pipe and opening into said intake manifold branch passage for injecting fuel thereinto, a fuel injection control valve associated with said fuel injection nozzle and having solenoid means for selectively opening and closing said fuel injection nozzle, and an electronic control circuit electrically connected to said solenoid means of fuel injection control valve, said electronic control circuit including an engine driven triggering device for producing a pulse signal dependent upon the engine speed and the crankshaft position and a pulse with calculating circuit connected to said engine driven triggering device and responsive to said pulse signal for producing a fuel injection pulse signal to be supplied to said solenoid means of said fuel injection control valve, said pulse width calculating circuit having means for decreasing the pulse width of said fuel injection pulse signal in proportion to the engine speed, whereby the pressure of said pressurized fuel to be injected into said intake manifold branch passage is increasing substantially proportionally with an increase in the engine speed whereas the pulse width of said fuel injection pulse signal decreases proportionally with an increase in the engine speed, and the quantity of the fuel to be injected for each cycle of the engine operation remains substantially unchanged irrespective of the variation in the engine speed.

Claim 3

A fuel injection system for an internal combustion engine having an intake manifold, and an intake manifold branch passage leading to an engine cylinder, said fuel injection system comprising, in combination, a fuel tank for storing a fuel to be supplied to said engine cylinder, a fuel pump connected to said fuel tank and driven by said engine to pump the fuel from said fuel tank at a pressure substantially proportional to the engine speed, a fuel distributing pipe connected to said fuel pump, pressure regulating means connected to said fuel distributing pipe for regulating the pressure of fuel therein, said pressure regulating means having first and second chambers, saId first chamber having an inlet port communicating with said fuel distributing pipe and an outlet port communicating with said second chamber, said second chamber storing fuel flowing thereinto and connected to said fuel tank for discharging the fuel in said second chamber to said fuel tank, a spool valve slidably received in said first chamber for controlling the degree of communication between said inlet and outlet ports thereby to regulate the pressure of fuel in said fuel distributing pipe, and diaphragm means associated with said pressure regulating means for controlling the movement of said spool valve, said diaphragm means including a housing having therein a vacuum chamber communicating with said intake manifold, a diaphragm secured to said housing and responsive to an intake manifold vacuum, said diaphragm being interconnected to said spool valve of said pressure regulating means and spring means disposed in said vacuum chamber for biasing said diaphragm to a position in which said spool valve is moved to decrease the degree of communication between said inlet and outlet ports of said pressure regulating means, a fuel injection nozzle connected to said fuel distributing pipe and opening into said intake manifold branch passage for injecting fuel thereinto, a control valve associated with said fuel injection nozzle and having solenoid means for opening and closing said fuel injection nozzle, and electronic control means electrically connected to said solenoid means of said control valve, said electronic control means including an engine driven triggering device for producing a pulse signal dependent upon the engine speed and the crankshaft position and a pulse width calculating circuit connected to said engine driven triggering device and responsive to said pulse signal for producing a fuel injection pulse signal to be supplied to said solenoid means of said control valve, said pulse width calculating circuit having means for decreasing the pulse width of said fuel injection pulse signal in proportion to the engine speed, whereby the pressure of said fuel to be injected into said intake manifold branch passage is increasing substantially proportionally with an increase in the engine speed whereas the pulse width of said fuel injection pulse signal decreases proportionally with an increase in the engine speed, and the quantity of the fuel to be injected for each cycle of the engine operation remains substantially unchanged irrespective of the variation in the engine speed.

Claim 4

A fuel injection system for an internal combustion engine having an intake manifold, and an intake manifold branch passage leading to an engine cylinder, said fuel injection system comprising, in combination, a fuel tank for storing a fuel to be supplied to said engine cylinder, a fuel pump connected to said fuel tank and driven by said engine to pump the fuel from said fuel tank at a pressure substantially proportional to the engine speed, a fuel distributing pipe connected to said fuel pump, pressure regulating means connected to said fuel distributing pipe for regulating the pressure of fuel therein, said pressure regulating means having first and second chambers, saId first chamber having an inlet port communicating with said fuel distributing pipe and an outlet port communicating with said second chamber, said second chamber storing fuel flowing thereinto and connected to said fuel tank for discharging the fuel in said second chamber to said fuel tank, a spool valve slidably received in said first chamber for controlling the degree of communication between said inlet and outlet ports thereby to regulate the pressure of fuel in said fuel distributing pipe, and diaphragm means associated with said pressure regulating means for controlling the movement of said spool valve, said diaphragm means including a housing having therein a vacuum chamber communicating with said intake manifold, a diaphragm secured to said housing and responsive to an intake manifold vacuum, said diaphragm being interconnected to said spool valve of said pressure regulating means and spring means disposed in said vacuum chamber for biasing said diaphragm to a position in which said spool valve is moved to decrease the degree of communication between said inlet and outlet ports of said pressure regulating means, a fuel injection nozzle connected to said fuel distributing pipe and opening into said intake manifold branch passage for injecting fuel thereinto, a control valve associated with said fuel injection nozzle and having solenoid means for opening and closing said fuel injection nozzle, and electronic control means electrically connected to said solenoid means of said control valve, said electronic control means including an engine driven triggering device for producing a pulse signal dependent upon the engine speed and the crankshaft position and a pulse width calculating circuit connected to said engine driven triggering device and responsive to said pulse signal for producing a fuel injection pulse signal to be supplied to said solenoid means of said control valve, said pulse width calculating circuit having means for decreasing the pulse width of said fuel injection pulse signal in proportion to the engine speed, whereby the pressure of said fuel to be injected into said intake manifold branch passage is increasing substantially proportionally with an increase in the engine speed whereas the pulse width of said fuel injection pulse signal decreases proportionally with an increase in the engine speed, and the quantity of the fuel to be injected for each cycle of the engine operation remains substantially unchanged irrespective of the variation in the engine speed.

Claim 5

A fuel injection system as claimed in claim 2, further comprising a mechanical linkage operatively interconnecting said diaphragm means with said pressure regulating means, said mechanical linkage having a lever at its one end connected to said diaphragm of said diaphragm means and having a connecting pin attached to the other end of said lever, and angled arm pivotally engaging at its one end with said connecting pin and rotatable about a stationary pivot, a bellows connected with another end of said angled arm for varying the position of said angled arm in response to the atmospheric pressure and temperature, and a spring member provided for biasing said another end of said angled arm against the force of said bellows, said lever being connected at its intermediate portion to said spool valve of said pressure regulating means, whereby movement of said lever caused by changes in the intake manifold vacuum and the atmospheric pressure and temperature varies the relative position of said spool valve thereby to vary the degree of communication between the inlet and outlet ports of said pressure regulating means.

Claim 6

A fuel injection system for an internal combustion engine having an intake manifold, and an intake manifold branch passage leading to an engine cylinder, said fuel injection system comprising, in combination, a fuel tank for storing fuel to be supplied to said engine cylinder, a fuel pump connected to said fuel tank and driven by said engine to pump the fuel from saiD fuel tank at a pressure substantially proportional to the engine speed, a fuel distributing pipe connected to said fuel pump, pressure regulating means connected to said fuel distributing pipe for regulating the pressure of fuel therein, said pressure regulating means having first and second chambers, said first chamber having an inlet port communicating with said fuel distributing pipe and an outlet port communicating with said second chamber, said second chamber storing fuel flowing thereinto and connected to said fuel tank for discharging the fuel in said second chamber to said fuel tank, a spool valve slidably received in said first chamber for controlling the degree of communication between said inlet and outlet ports thereby to regulate the pressure of fuel in said fuel distributing pipe, and diaphragm means associated with said pressure regulating means for controlling the movement of said spool valve, said diaphragm means having a housing with a vacuum chamber communicating with said intake manifold, a diaphragm secured to said housing and responsive to an intake manifold vacuum, said diaphragm being interconnected to said spool valve of said pressure regulating means and spring means disposed in said vacuum chamber for biasing said diaphragm to a position in which said spool valve is moved to decrease the degree of communication between said inlet and outlet ports of said pressure regulating means, a mechanical linkage operatively interconnecting said diaphragm means with said pressure regulating means, said mechanical linkage having a lever at its one end connected to said diaphragm of said diaphragm means and having a connecting pin attached to the other end of said lever, an angled arm pivotally engaging at its one end with said connecting pin and rotatable about a stationary pivot, a bellows connected with another end of said angled arm for varying the position of said angled arm in response to the atmospheric pressure and temperature, and a spring member provided for biasing said another end of said angled arm against the force of said bellows, said lever being connected at its intermediate portion to said spool valve of said pressure regulating means, a fuel injection nozzle connected to said fuel distributing pipe and opening into said intake manifold branch passage for injecting fuel thereinto, a control valve associated with said fuel injection nozzle and having solenoid means for opening and closing said fuel injection nozzle, and electronic control means electrically connected to said solenoid means of said control valve, said electronic control means having an engine driven triggering device for producing a pulse signal having a pulse width dependent upon the engine speed and the crankshaft position and a pulse width calculating circuit connected to said engine driven triggering device, said pulse width calculating circuit having a switching transistor connected at its base to said engine driven triggering device, a saw-tooth wave generator connected to said switching transistor, and a Schmidt circuit having an input connected to said saw-tooth wave circuit and an output connected to said solenoid means of said control valve, said Schmidt circuit comparing an input voltage received from said saw-tooth wave circuit with a certain reference voltage for producing a fuel injection pulse signal having the pulse width decreasing in porportion to the engine speed, whereby the pressure of said fuel to be injected into said intake manifold branch passage is increasing substantially proportionally with an increase in the engine speed whereas the pulse width of said fuel injection pulse signal decreases proportionally with an increase in the engine speed, and the quantity of the fuel to be injected for each cycle of the engine operation remains substantially unchanged irrespective of the variation in the engine speed.

Claim 7

A fuel injection system for an internal combustion engine having an intake manifold, and an intake manifold branch passage leading to an engine cylinder, said fuel injection system comprising, in combination, a fuel tank for storing fuel to be supplied to said engine cylinder, a fuel pump connected to said fuel tank and driven by said engine to pump the fuel from saiD fuel tank at a pressure substantially proportional to the engine speed, a fuel distributing pipe connected to said fuel pump, pressure regulating means connected to said fuel distributing pipe for regulating the pressure of fuel therein, said pressure regulating means having first and second chambers, said first chamber having an inlet port communicating with said fuel distributing pipe and an outlet port communicating with said second chamber, said second chamber storing fuel flowing thereinto and connected to said fuel tank for discharging the fuel in said second chamber to said fuel tank, a spool valve slidably received in said first chamber for controlling the degree of communication between said inlet and outlet ports thereby to regulate the pressure of fuel in said fuel distributing pipe, and diaphragm means associated with said pressure regulating means for controlling the movement of said spool valve, said diaphragm means having a housing with a vacuum chamber communicating with said intake manifold, a diaphragm secured to said housing and responsive to an intake manifold vacuum, said diaphragm being interconnected to said spool valve of said pressure regulating means and spring means disposed in said vacuum chamber for biasing said diaphragm to a position in which said spool valve is moved to decrease the degree of communication between said inlet and outlet ports of said pressure regulating means, a mechanical linkage operatively interconnecting said diaphragm means with said pressure regulating means, said mechanical linkage having a lever at its one end connected to said diaphragm of said diaphragm means and having a connecting pin attached to the other end of said lever, an angled arm pivotally engaging at its one end with said connecting pin and rotatable about a stationary pivot, a bellows connected with another end of said angled arm for varying the position of said angled arm in response to the atmospheric pressure and temperature, and a spring member provided for biasing said another end of said angled arm against the force of said bellows, said lever being connected at its intermediate portion to said spool valve of said pressure regulating means, a fuel injection nozzle connected to said fuel distributing pipe and opening into said intake manifold branch passage for injecting fuel thereinto, a control valve associated with said fuel injection nozzle and having solenoid means for opening and closing said fuel injection nozzle, and electronic control means electrically connected to said solenoid means of said control valve, said electronic control means having an engine driven triggering device for producing a pulse signal having a pulse width dependent upon the engine speed and the crankshaft position and a pulse width calculating circuit connected to said engine driven triggering device, said pulse width calculating circuit having a switching transistor connected at its base to said engine driven triggering device, a saw-tooth wave generator connected to said switching transistor, and a Schmidt circuit having an input connected to said saw-tooth wave circuit and an output connected to said solenoid means of said control valve, said Schmidt circuit comparing an input voltage received from said saw-tooth wave circuit with a certain reference voltage for producing a fuel injection pulse signal having the pulse width decreasing in porportion to the engine speed, whereby the pressure of said fuel to be injected into said intake manifold branch passage is increasing substantially proportionally with an increase in the engine speed whereas the pulse width of said fuel injection pulse signal decreases proportionally with an increase in the engine speed, and the quantity of the fuel to be injected for each cycle of the engine operation remains substantially unchanged irrespective of the variation in the engine speed.