Engine control apparatus for improved fuel economy

Apparatus for improving the efficiency with which mechanical power is produced by an Otto cycle engine and delivered to a load, the engine having a throttle valve device used to provide substantially all throttling of substantially all combustion air consumed by the engine to thereby provide control over at least a major range of brake torque produced at a power output shaft of the engine, the apparatus comprising:

• an intake mixture preparation system for the engine operative to automatically use intake charge dilution to provide benefits of (1) reducing brake specific fuel consumption of the engine and (2) suppressing autoignition in the engine when density of combustion air consumed by the engine is substantially maximized with the throttle valve device being at least effectively wide open, said wide open throttle benefits being provided by said intake mixture preparation system over at least half of a range of operating speed of said engine output shaft required to satisfy all operating conditions of the load,
• a discrete-ratio gearbox which receives power from the engine power output shaft and which has a gearbox power output shaft that provides substantially all mechanical energy for powering the load, substantially all of said mechanical energy for powering the load being transferred from the engine to the load without a significant time delay,
• and means operative to select a gear ratio according to a mapping of gear ratios available in said gearbox onto an area of rotational speed of said gearbox power output shaft versus position of an operator input means in response to which position the engine throttle valve device is adjusted, said mapping utilizing substantially maximized density of the engine combustion air, including positions of the engine throttle valve device which substantially minimize throttling of the engine combustion air, to establish engine power levels which extend upward from below one-half of the engine's maximum power level, said mapping having an acceptable amount of shift schedule hysteresis and at the same time allowing elimination of substantially all unacceptable gaps in power available for driving the load,
• whereby performance of the engine approaching that available using a highly efficient continuously variable transmission is available using said discrete-ratio gearbox in place of said CVT.

Apparatus for improving the overall efficiency with which mechanical power is both produced by an Otto cycle engine and delivered to a load, the engine consuming only an intake charge comprising air and fuel in stoichiometric proportion thereto to thereby produce the mechanical power, the engine having at least one combustion chamber and said fuel and said air at least beginning to merge before entering each of said at least one combustion chamber, a power output shaft of the engine providing the mechanical power for delivery to the load and having an overall range of rotational speed consisting of all values of rotational speed with which said output shaft provides the mechanical power for delivery to the load, the apparatus comprising:

• a designated induction-and-fuel-metering system for the engine selected from a naturally-aspirated induction-and-fuel-metering system and a supercharged induction-and-fuel-metering system, said naturally-aspirated induction-and-fuel-metering system comprising a throttle valve device and a first intake mixture preparation means, said throttle valve device being interposed in a flow comprising substantially all of said engine intake air to thereby provide control of the mechanical power for delivery to the load, said throttle valve device having an actually wide open position which minimizes density reduction of said intake air caused by thermodynamic free expansion in said flow of intake air as said intake air passes through said throttle valve device, said minimization of density reduction occurring when said engine output shaft speed is maximized in said overall speed range of said engine output shaft, said throttle valve device being effectively wide open whenever said flow of engine intake air is substantially free of density reduction of said intake air caused by thermodynamic free expansion in said flow of intake air as said intake air passes through said throttle valve device, and said throttle valve device also being effectively wide open whenever said throttle valve device is substantially in said actually wide open position, said first intake mixture preparation means having an efficient wide-open-throttle calibration for automatically providing full dilution of the intake charge when said throttle valve device is effectively wide open, said wide-open-throttle calibration extending substantially throughout an efficient rotational speed range of said engine output shaft which is at least 50% as wide as said overall engine range when each of said efficient and said overall engine speed ranges is expressed as a positive range of revolutions per minute, the intake charge consisting of said full intake charge dilution and said stoichiometric portion of the intake charge at substantially all times when said first intake mixture preparation means is implementing said wide-open-throttle calibration, with said engine output shaft operating at each particular speed value within said efficient engine speed range said full intake charge dilution both having a particular composition and being in a weight proportion to said stoichiometric portion which substantially minimizes brake specific cost measured at said engine output shaft with (a) said engine output shaft operating at said particular speed value, (b) said throttle valve device being effectively wide open, (c) ambient air density being representative of anticipated operating conditions for the engine and (d) the intake charge consisting of said stoichiometric portion and dilution of said particular composition, said brake specific cost comprising mass amount of said fuel consumed by the engine to produce one brake-horsepower-hour of mechanical energy, and said supercharged induction-and-fuel-metering system comprising said throttle valve device, a supercharger for the engine and a second intake mixture preparation means, said second intake mixture preparation means having an efficient full-boost-pressure calibration for automatically providing full-boost dilution of the intake charge when said supercharger is providing full boost pressure to the engine, said full-boost-pressure calibration extending substantially throughout said efficient engine speed range and the intake charge consisting of said full-boost intake charge dilution and said stoichiometric portion of the intake charge at substantially all times when said second intake mixture preparation means is implementing said full-boost-pressure calibration, with said engine output shaft operating at each constant speed value within said efficient engine speed range said full-boost dilution of the intake charge having a specific composition and being in at least that weight proportion to said stoichiometric portion which substantially minimizes said brake specific cost measured at said engine output shaft with (a) said engine output shaft operating at said constant speed value, (b) said supercharger providing full boost pressure to the engine, (c) ambient air density being representative of anticipated operating conditions for the engine and (d) the intake charge consisting of said stoichiometric portion and dilution of said specific composition, the engine having torque control means which comprises said throttle valve device and which is used to provide substantially all regulation of brake torque produced by the engine output shaft at each fixed value of said engine output shaft speed throughout said efficient engine speed range, said designated induction-and-fuel-metering system being calibrated to automatically regulate mass consumption rate of said fuel by the engine to a magnitude which depends upon both said engine output shaft speed and status of said torque control means, said automatic regulation of fuel consumption comprising said wide-open-throttle calibration if the apparatus includes said naturally-aspirated induction-and-fuel-metering system and said automatic regulation of fuel consumption comprising said full-boost-pressure calibration if the apparatus includes said supercharged induction-and-fuel-metering system,
• discrete-ratio means which couples said engine output shaft to a power input element of the load through a number of discrete rotational speed ratios at least equal to two, each of said number of discrete speed ratios being expressed as a dimensionless ratio of rotational speed of an element of said discrete-ratio means driven by said engine output shaft to concurrent rotational speed of said input element of the load obtained with zero power loss due to slippage between said engine driven element and said load input element, a power unit comprising the engine and said discrete-ratio means having at least two operating modes with which the mechanical power is produced by the engine and delivered to said input element of the load, each one of said at least two operating modes having, in conjunction with said automatic regulation of engine fuel consumption provided by said designated induction-and-fuel-metering system, associated therewith a different topographical mode performance mapping of a surface of said brake specific cost substantially as measured at said input element of the load onto an area of said rotational speed of said input element of the load versus magnitude of the mechanical power substantially as measured at said input element of the load, said brake specific cost consisting of a sum of products which includes said mass amount of fuel consumed per brake-horsepower-hour, each of said products being a brake specific performance parameter multiplied by a weighting factor having a relative value chosen to optimize operation of said power unit,
• and means operative to select one of said at least two power unit operating modes according to a mapping of said at least two operating modes onto an area of said rotational speed of said input element of the load versus position of an operator input means in response to which position said torque control means is adjusted, said mapping utilizing substantially maximized density of said engine intake air to establish engine power levels extending upward from below one-half of the engine's maximum power level,
• whereby performance of the engine approaching the best obtainable using a continuously variable transmission is available using said discrete-ratio means in place of said CVT.

Apparatus for improving efficiency with which mechanical power is produced by a combustion engine and delivered to a load, the engine having torque control means which (1) comprises at least one engine control device and (2) is used to provide substantially all regulation of brake torque produced at a power output shaft of the engine, and the engine having means operative to automatically regulate mass consumption rate of fuel by the engine according to a schedule which depends on both of operating speed of said engine power output shaft and status of said engine torque control means, a first shift map of a selection of discrete gear ratio values on an area defined by an operating speed of the load and by said status of said engine torque control means (1) being derived from a second shift map of said selection of gear ratio values and (2) having unacceptable overlapping of different ones of said selection of gear ration values when said first shift map closes all unacceptable gaps in power available from the engine to drive the load, said overlapping of different gear ratio values on said first shift map being unacceptable in that upshifts performed according to said first shift map are unacceptably delayed when the load is accelerating while said status of said engine torque control means remains fixed, the apparatus comprising:

• a discrete-ratio gearbox which makes each of said selection of gear ratio values available for coupling said engine power output shaft to drive the load through a power output shaft of the gearbox, said operating speed of the load being identical to operating speed of said gearbox output shaft,
• gear ratio selection means operative to select and enable an optimum one of said selection of gear ratio values according to said second shift map of said section of gear ratio values, said second shift map being on an area defined by said operating speed of the load and by magnitude of the mechanical power substantially as delivered to the load, each one of said selection of gear ratio values having in conjunction with performance of the engine as established by said fuel consumption schedule a topographical map of brake specific cost of engine operation on said area of said second shift map, said brake specific cost of engine operation on said area of said second shift map, said brake specific cost of engine operation comprising mass amount of fuel consumed by the engine in delivering one brake-horsepower-hour of mechanical energy to the load and each individual point on said second shift map (1) having associated therewith particular values of said operating speed of the load and of said magnitude of the power as delivered to the load and (2) being associated by said second shift map with one of said selection of gear ratios values which has a candidate value of said brake specific cost of engine operation at least as low as that of any other of said selection of gear ratio values which is capable of allowing the engine to establish said particular values of load speed and power, each example of said selection of gear ratio values which are capable of allowing the engine to establish said particular values of load speed and power having its candidate value of said brake specific cost of engine operation obtained from (1) a specific one of said topographical maps of brake specific cost which applies to said example gear ratio value and (2) a location on said specific topographical map determined by said particular values of load speed and power, said second shift map thereby closing all of said unacceptable gaps in power without having said unacceptable gear ratio overlapping which occurs on said first shift map, said first shift map being derived from said second shift map by employing performance data for operating the engine and said gearbox using said fuel consumption schedule and an applicable one of said selection of gear ratio values, said performance data being used to convert each individual power magnitude on said second shift map to a value on said first shift map of status of said engine torque control means, input means operative to command a desired level for said magnitude of power as delivered to the load, said selection of an optimum gear ratio value by said gear ratio selection means being accomplished using said desired level of power as a value for said magnitude of power as delivered to the load, and drive-by-wire means operative to establish (a) a first range of said status of said engine torque control means for operation of the engine when a first of said selection of gear ratio values is enables in said gear box and (b) a second range of said status of said engine torque control means for operation of the engine when a second of said gear ratio values is enable in said gearbox, said first and said second ranges of torque control status strongly overlapping each other when said operating speed of the load holds a constant value, but said drive-by-wire means establishing said first range of torque control status at said constant load speed only when said input means is advanced to command a range of said desired level of power beyond that which causes said drive-by-wire means to establish said second range of torque control status at said constant load speed, said strong overlapping of said range of torque control status without corresponding overlapping in status of said input means existing throughout a broad range of said operating speed of the load within which broad speed range said first and said second ranges of torque control status are each changing,
• whereby said discrete-ratio gearbox facilitates performance of the engine approaching that available with a continuously variable transmission having a ratio range equal to that of said selection of gear ratio values, but said engine performance is achieved with neither unnecessary gaps in availability of power to drive the load nor excessive shift schedule hysteresis.