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Engine control apparatus for use in passenger cars and other applications includes a special calibration of the engine intake mixture preparation system. Although this calibration duplicates the optimum calibration for use with a continuously variable transmission (CVT), the apparatus instead includ

Engine control apparatus for use in passenger cars and other applications includes a special calibration of the engine intake mixture preparation system. Although this calibration duplicates the optimum calibration for use with a continuously variable transmission (CVT), the apparatus instead includes, for reasons of practicality, a discrete-ratio powershift transmission. Also included is a feedback control system which dispenses with the conventional mechanical connection between accelerator pedal and engine throttle valve. This drive-by-wire control system operates the engine as closely as is practical to the optimum CVT engine operating schedule, a predominantly wide-open-throttle engine operating schedule. The overall combination of special engine calibration and drive-by-wire control with a discrete-ratio transmission can offer the majority of the fuel economy advantage available with a CVT.

대표청구항 ▼

Apparatus for improving the efficiency with which mechanical power is produced for delivery to a load by an Otto cycle engine which consumes only an intake charge comprising air and fuel in stoichiometric proportion thereto to thereby produce the power for delivery to the load, the engine having at

Apparatus for improving the efficiency with which mechanical power is produced for delivery to a load by an Otto cycle engine which consumes only an intake charge comprising air and fuel in stoichiometric proportion thereto to thereby produce the power for delivery to the load, 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 power produced 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 power produced 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 power produced 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 speed 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 asid 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 of operating the engine 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 of engine operation being chosen to optimize operation of the engine and comprising mass amount of said fuel consumed by the engine to produce one brake-horsepower-hour of mechanical energy at said engine output shaft, 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 of operating the engine 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 air flow control means which comprises said throttle valve device and is operative to regulate mass consumption rate by the engine of said flow of engine intake air to thereby in turn regulate, throughout a continuous range which includes zero, brake torque produced by said 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 air flow 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, said automatic regulation of fuel consumption having associated therewith a topographical surface mapping of said brake specific cost of engine operation onto an area of power produced at said engine output shaft versus said engine output shaft speed, discrete-ratio means which couples said engine output shaft to the load through a total number of discrete speed ratios at least equal to two, each of said total number of speed ratios being expressed as a dimensionless ratio of said engine output shaft speed to a concurrent rotational speed of the load obtained with zero power loss due to slippage between the engine and the load, a best choice shift schedule associating a single best ratio selected from said total number of speed ratios to each individual load combination included in all achievable load combinations of said rotational speed of the load and the power produced for delivery to the load, each one of said all achievable load combinations having associated therewith candidate engine speeds obtained only by multiplying each one of said total number of speed ratios by a value of said rotational load speed taken from said one of said all achievable load combinations, each individual candidate engine speed included in all those candidate engine speeds both obtained from said individual load combination and existing within said overall engine speed range having associated therewith a candidate brake specific cost obtained only from said engine mapping of brake specific cost at a point on said mapping located by (a) magnitude on said engine mapping of said power produced by the engine at said engine output shaft being equal to a value of the power produced for delivery to the load given by said individual load combination and (b) magnitude on said engine mapping of said engine output shaft speed being equal to said individual candidate engine speed, said candidate brake specific cost associated with said individual candidate engine speed being infinite if said point falls outside of said engine mapping as determined by actual power-producing capability of the engine, a best candidate brake specific cost having a magnitude at least as low as that of any other candidate brake specific cost selected from all candidate brake specific costs associated with said individual load combination, said single best ratio associated with said individual load combination by said best choice shift schedule being that ratio which secures a candidate engine speed which in turn secures said best candidate brake specific cost, and when all candidate brake specific costs obtained for said individual load combination are infinite said best ratio having a candidate engine speed higher than any other candidate engine speed both within said overall engine speed range and associated with said individual load combination, and ratio control means operative to select both upshifts and downshifts between speed ratios in said total number of speed ratios in substantial accordance with said best choice shift schedule, said substantial accordance being from the standpoint of a cost rate mathematically integrated over a time period during which the power produced for delivery to the load and said rotational speed of the load pass through a broad range of combinations representative of an operational lifetime anticipated to be common for the engine, said cost rate consisting of current magnitude of said brake specific cost of engine operation multiplied by current magnitude of the power produced for delivery to the load, whereby an engine calibration selected from said wide-open-throttle calibration and said full-boost-pressure calibration enhances operating efficiency of the engine and said ratio control means selects speed ratios compatible with efficient operation of the engine.