# US 5,704,336 A · Fuel system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,704,336 A - Document ID: US5704336A - Status: Granted - Kind: A - Application number: 08/612,259 - Filed: 1996-03-07 - Granted: 1998-01-06 - Earliest claimed: 1995-03-08 - Assignees: Lucas Industries public limited company - Inventors: Jeremy Stephen Wrobel - Web page: https://patentgrep.com/patent/US5704336A ## CPC - G01D 18/001: {Calibrating encoders} - F02D 41/0097: {using means for generating speed signals} - G01D 5/2449: {using hard-stored calibration data} - G01P 3/488: delivered by variable reluctance detectors - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) ## Abstract A fuel system for an internal combustion engine (10) includes a controller (14) which controls the operation of an engine fuel pump (13). Signals are supplied to the controller by a transducer (16) which is responsive to the passage of teeth formed on the periphery of a wheel (12) which is mounted on the engine crankshaft. In order to generate an engine speed signal it is necessary to know the tooth spacing errors and these are determined by recording two time pulse sequences of signals from the transducer at different engine speeds and loads and then processing those signals to firstly determine the periodic component of the signals due to the fluctuation of engine speed which occurs due to the individual power strokes of the engine. ## Claims ### Claim 1 A fuel system for an internal combustion engine comprising a fuel pump, a controller for controlling the operation of the fuel pump so that fuel is delivered to the engine at a required time and in a desired quantity, means for supplying a demand signal to the controller, a wheel driven by the engine, a plurality of indicia on the wheel and positioned about an axis of rotation of the wheel, transducer means responsive to the passage of said indicia as the wheel rotates, means responsive to pulse signals generated by said transducer means for measuring time intervals between the passage of the indicia past the transducer means, wherein said measuring means comprises means for recording two time pulse sequences of signals from the transducer means at different engine speed and load operating conditions, means for determining actual indicia spacing errors from said two time pulse sequences of signals and means for calculating the engine speed using the actual indicia spacing errors and the measured time intervals between the pulses produced by said transducer means. ### Claim 2 (depends on 1) A fuel system according to claim 1, wherein the means for determining the actual indicia spacing error comprises means for determining a PERIODIC sequence, wherein said PERIODIC sequence is the difference between the periodic components of one of said time pulse sequences and the periodic components of a scaled version of the other time pulse sequence. ### Claim 3 (depends on 1) A fuel system according to claim 1, further comprising means for detecting if the engine is running at a nominal constant speed prior to recording each of said time pulse sequences of signals, said detecting means including means for summing sample values obtained at regular sampling points over at least one period of the periodic component of the engine speed fluctuation, and means for comparing the sum with a similar sum obtained by starting at another sampling point to determine whether or not the nominal speed of the engine is constant. ### Claim 4 (depends on 3) A fuel system according to claim 3, wherein said another sampling point is the next sampling point. ### Claim 5 (depends on 3) A fuel system according to claim 3, further comprising means for adjusting the values of said signals produced by said transducer means prior to recording said time pulse sequence signals if said nominal speed of the engine is not constant. ### Claim 6 (depends on 3) A fuel system according to claim 3, further comprising means for summing said sample values at sampling points extending over one revolution of the wheel. ### Claim 7 A method of calculating the speed of an internal combustion engine within a fuel system, said method comprising: delivering fuel to the engine at a required time and in a desired quantity; providing a wheel driven by the engine about an axis of rotation, wherein said wheel has a plurality of indicia about the axis of rotation; generating pulse signals in response to passage of said indicia as the wheel rotates; measuring time intervals between the passage of the indicia; recording two time pulse sequences of signals at different engine speed and load operating conditions; determining actual indicia spacing errors from said two time pulse sequences of signals; and using the actual indicia spacing errors and the time pulse sequences to determine engine speed. ### Claim 8 (depends on 7) The method according to claim 7, further comprising determining a PERIODIC sequence to determine actual indicia spacing errors, wherein said PERIODIC sequence is the difference between the periodic components of one of said time pulse sequences and the periodic components of a scaled version of the other time pulse sequence. ### Claim 9 (depends on 7) The method according to claim 7, further comprising: detecting if the engine is running at a nominal constant speed prior to recording each of said time pulse sequences of signals; summing sample values obtained at regular sampling points over at least one period of the periodic component of the engine speed fluctuation; and comparing the sample value with a similar sum obtained by starting at another sampling point to determine whether or not the nominal speed of the engine is constant. ### Claim 10 (depends on 9) The method according to claim 9, wherein said another sampling point is the next sampling point. ### Claim 11 (depends on 9) The method according to claim 9, further comprising adjusting the values of said signals prior to recording said time pulse sequence signals if said nominal speed of the engine is not constant. ### Claim 12 (depends on 9) The method according to claim 9, further comprising summing said sample values at sampling points extending over one revolution of the wheel.