Two-cycle engine with electronic fuel injection

Abstract

A fuel injection controlling device for a two-cycle engine comprising an air manifold; a throttle valve; a fuel injector; a fuel supply system including a fuel pump; a battery voltage sensor; an air temperature sensor; an engine speed sensor; a timing sensor; a barometric pressure sensor; a throttle position sensor; a first data processor for receiving and processing sensing signals for determining fuel injector duration and timing and fuel pump operating speed; a first data processor temperature sensor for sensing the relative temperature of certain electronic components in the first data processor; a heater operatively associated with the first data processor electronic components for selectively heating the electronic components; and a second data processor operable independently of the first data processor for receiving an electronic component temperature sensing signal and for generating a control signal to the heater responsive thereto for heating the components when the temperature thereof is below a predetermined minimum value. The questions raised in reexamination request No. 90/002,861, filed Oct. 9, 1992, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CRF 1.570(e).

What is claimed is: 
     
       1. A fuel injection system for a two-stroke cycle engine of the type comprising at least one cylinder, a crankcase associated with said cylinder, a piston reciprocally mounted in said cylinder and crankcase; a reciprocally openable and closable crankcase inlet for enabling combustible fluid to be drawn into the crankcase, a reciprocally openable and closable transfer port for transferring combustible fluid compressed in said crankcase to said cylinder, an ignition system for igniting compressed combustible fluid in said cylinder, a reciprocally openable and closable exhaust port in said cylinder for enabling exhaust of burned combustible fluid from said cylinder, a crankshaft connected to said piston for transferring mechanical energy from said piston to a drive unit, and an electrical energy supply source including a battery for operating the ignition system and other electrical components, comprising: (a) fuel injection means for injecting fuel for combustion within said cylinder;   (b) fuel supply means for supplying fuel to said fuel injection means;   (c) battery voltage sensing means for sensing battery voltage and for providing a battery voltage sensing signal representative thereof;   (d) air temperature sensing means for sensing the temperature of ambient air and for providing an air temperature signal representative thereof;   (e) engine speed sensing means for sensing the speed of revolution of said engine and for providing an engine speed signal representative thereof;   (f) timing sensing means for sensing each occurrence of a predetermined cyclically repeating state of said engine and for providing a timing signal indicative thereof;   (g) barometric pressure sensing means for sensing atmospheric air pressure and for generating a barometric pressure sensing signal representative thereof;   (h) throttle position sensing means for sensing the relative amount of opening of .[.said.]. .Iadd.a .Iaddend.throttle valve means and for generating a throttle position signal representative thereof;   (.Iadd.i.Iaddend.) engine temperature sensing means for sensing engine temperature and providing an engine temperature signal representative thereof;   (.[.i.]..Iadd.j.Iaddend.) first data processing means for receiving and processing said sensing signals comprising: (i) means for processing said engine speed sensing signal and said throttle position sensing signal and for generating a priming control signals to said fuel injection means for selectively injecting or not injecting fuel into .[.said.]. .Iadd.a .Iaddend.manifold means based on said engine speed signal and said throttle position signal;   (ii) means for receiving and processing said engine speed signal and throttle position signal for determining a base fuel injection value;   (iii) means for receiving and processing said air temperature signal and calculating an air temperature modification value of said base fuel injection value;   (iv) means for receiving and processing said barometric pressure sensing signal for calculating a barometric pressure modification value of said base fuel injection value;   (v) means for receiving and processing .[.said.]. .Iadd.an .Iaddend.engine temperature signal for calculating an engine temperature modification value of said base fuel injection value;   (vi) means for determining a total fuel injection value representative of the total fuel amount which is to be injected by said fuel injection means during a single two-stroke operating cycle of said piston from said base fuel injection value, said air temperature modification value, said barometric pressure modification value, and said engine temperature modification value;   (vii) means for determining an injector open duration interval based on said total fuel injection value and a known fuel output rate capacity of said fuel injection means;   (viii) means for generating a control signal for opening said injection means for said determined injector .Iadd.open .Iaddend.duration .[.open.]. interval at a predetermined point in time determined from said timing sensing signal;   (ix) means for receiving and processing said engine speed sensing signal for generating a pump control signal in response thereto for maintaining .[.said.]. .Iadd.a .Iaddend.pump at an optimum operating speed for providing .[.said.]. .Iadd.a .Iaddend.predetermined maximum operating pressure in .[.said.]. .Iadd.a .Iaddend. fuel circulation conduit means at said pump. .Iadd.     
     
     
       2.  A fuel injection system for a two-stroke cycle engine of the type comprising at least one cylinder, a crankcase associated with said cylinder, a piston reciprocally mounted in said cylinder and crankcase; a reciprocally openable and closable crankcase inlet for enabling combustible fluid to be drawn into the crankcase, a reciprocally openable and closable transfer port for transferring combustible fluid compressed in said crankcase to said cylinder, an ignition system for igniting compressed combustible fluid in said cylinder, a reciprocally openable and closable exhaust port in said cylinder for enabling exhaust of burned combustible fluid from said cylinder, a crankshaft connected to said piston for transferring mechanical energy from said piston to a drive unit, and an electrical energy supply source including a battery for operating the ignition system and other electrical components, comprising: fuel injection means for injecting fuel for combustion with air within said cylinder;   air temperature sensing means for sensing the temperature of air to be mixed with the fuel and for providing an air temperature signal representative thereof;   engine speed sensing means for sensing the speed of revolution of said engine and for providing an engine speed signal representative thereof;   engine temperature sensing means for sensing the temperature of the engine and for providing an engine temperature signal representative thereof;   timing sensing means for sensing each occurrence of a predetermined cyclically repeating state of said engine and for providing a timing signal indicative thereof;   barometric pressure sensing means for sensing atmospheric air pressure and for generating a barometric pressure sensing signal representative thereof;   throttle position sensing means for sensing the relative amount of opening of a throttle valve means and for generating a throttle position signal representative thereof;   first data processing means for receiving and processing said sensing signals comprising: means for receiving and processing said engine speed signal and throttle position signal for determining a base fuel injection value;   means for receiving and processing said air temperature signal and calculating an air temperature modification value of said base fuel injection value;   means for receiving and processing said barometric pressure sensing signal for calculating a barometric pressure modification value of said base fuel injection value;   means for receiving and processing the engine temperature signal for calculating an engine temperature modification value of said base fuel injection value;   means for determining a total fuel injection value representative of the total fuel amount which is to be injected by said fuel injection means during a single two-stroke operating cycle of said piston from said base fuel injection value, said air temperature modification value, said barometric pressure modification value, and said engine temperature modification value;   means for determining an injector open duration interval based on said total fuel injection value and a known fuel output rate capacity of said fuel injection means;   means for generating a control signal for opening said injection means for said determined injector open duration interval at a predetermined point in time determined from said timing sensing signal. .Iaddend. .Iadd.     
     
     
       3.  A fuel injection system for a two-stroke cycle internal combustion engine having a movable throttle valve, comprising in combination: a fuel injector having means to control the quantity of fuel injected which means is responsive to the characteristics of a signal representing a total fuel injection value,   a first data processor, including electronic memory for storing an array of values representing fuel flow rates at predetermined engine operating conditions, addressable as a function of throttle valve position and engine rotational speed and having an output representative of a base fuel injection value,   a throttle valve position sensor, including means for addressing the electronic memory,   means for addressing the electronic memory with a signal representative of engine rotational speed,   a second electronic data processor having an output operably connected to the control means of the fuel injector and responsive to the base fuel injection value and responsive to electronic signals representing air temperature, barometric pressure and engine temperature for modifying the base fuel injection value into the total fuel injection value,   an air temperature sensor, including means generating and conducting to the second data processor a signal representative of air temperature,   a barometric pressure sensor including means generating and conducting to the second data processor a signal representative of barometric pressure,   an engine temperature sensor, including means generating and conducting to the second data processor a signal representative of the engine temperature; and   timing sensing means for generating an electrical signal responsive to a predetermined cyclically repeating occurrence in the engine and connected to the input of the second data processor means, for determining the timing of the output of the second data processor. .Iaddend. .Iadd.   
     
     
       4.  A method of controlling the amount of fuel injected per at least one repetitive occurrence into a two-stroke cycle internal combustion engine having a fuel injector and throttle valve comprising the steps of: storing an array of values representing base fuel flow rates at predetermined engine operating parameters and conditions,   selecting a base fuel flow rate value as a function of throttle valve position and engine rotational speed,   modifying the base fuel flow rate value as a function of engine temperature, air temperature and barometric pressure to obtain a total fuel flow value,   controlling the quantity of fuel injected per at least one repetitive occurrence in the engine in response to the total fuel flow value,   sensing a predetermined cyclically repeating occurrence in the rotation of the engine, and   controlling the occurrence of the fuel injector operation in response to the said sensing. .Iaddend.