# US 5,706,779 A · Vehicle speed limiting system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,779 A - Document ID: US5706779A - Status: Granted - Kind: A - Application number: 08/672,681 - Filed: 1996-06-28 - Granted: 1998-01-13 - Earliest claimed: 1996-06-28 - Inventors: John T. Hewitt - Web page: https://patentgrep.com/patent/US5706779A ## CPC - B60K 31/00: Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator - B60K 31/04: and means for comparing one electrical quantity, e.g. voltage, pulse, waveform, flux, or the like, with another quantity of a like kind, which comparison means is involved in the development of an electrical signal which is fed into the controlling means - B60K 31/185: {connected to the speedometer display, e.g. by sensors or switches responsive to the position of the indicator needle} - F02D 17/04: rendering engines inoperative or idling, e.g. caused by abnormal conditions (dependent on lubricating conditions F01M1/22; dependent on cooling F01P5/14) - F02M 59/38: Pumps characterised by adaptations to special uses or conditions - F02M 59/447: {means specially adapted to limit fuel delivery or to supply excess of fuel temporarily, e.g. for starting of the engine (combined with fuel pump regulating devices F02D)} - F02M 63/0205: {for cutting-out pumps or injectors in case of abnormal operation of the engine or the injection apparatus, e.g. over-speed, break-down of fuel pumps or injectors (safety devices acting on engine fuel system on lubricant pressure failure F01M1/24); for cutting-out pumps for stopping the engine} - B60W 2710/0616: Position of fuel or air injector - F02B 3/06: with compression ignition (compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02) - B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) ## Abstract A vehicle speed limiting system for a vehicle having an engine which includes a plurality of fuel injectors coupled to an inline, low volume fuel injection pump operative to successively trigger a flow of fuel directly to the individual fuel injectors. The vehicle speed is converted to a speed signal which, when it reaches a preset limit, is utilized by the system control to close a fuel control valve through which fuel normally passes to the injection pump, and also to simultaneously open a pressure regulator. The fuel control valve includes a small orifice to pass just enough fuel to prevent pump cavitation. The system is characterized by a low fuel residual upon cutoff by the fuel control valve so that the engine speed is quickly slowed for lack of fuel. ## Claims ### Claim 1 A vehicle speed limiting system for a vehicle having an engine which includes a plurality of fuel injectors; fuel supply means; and an injection pump operative to successively trigger a flow of fuel directly to the individual fuel injectors, the system comprising: speed sensing means for producing a speed signal related to the engine speed; pressure regulator means coupled to the fuel supply means; fuel control means for metering fuel flow to the engine, the fuel control means being coupled to the pressure regulator means, to the fuel supply means and to the injection pump, the fuel control means including a first passageway between the fuel supply means and the injection pump, and also a second passageway smaller than the first passageway between the fuel supply means and the injection pump, the fuel control means normally being in an open state allowing fuel flow through the first passageway, the fuel control means including a valve actuable to a closed state preventing fuel flow through the first passageway and allowing fuel flow only through the small passageway; the pressure regulator means normally being in a closed state to prevent fluid flow return from the fuel control means to the fuel supply means, the pressure regulator means being actuable to an open state allowing such return flow simultaneously with actuation of the fuel control means to a closed state; and system control means operative to place the fuel control valve in the open state and the regulator valve in the closed state, and further operative in response to a speed signal in excess of a preset limit to place the regulator valve in the open state and the fuel control valve in the closed state whereby fuel flow to the injection pump is confined to the second passageway in the fuel control means. ### Claim 2 (depends on 1) A speed limiting system according to claim 1 wherein the injection pump is an inline, low volume type characterized by a low residual amount of fuel between the injection pump and the injectors upon placement of the fuel control means in the closed state. ### Claim 3 (depends on 1) A speed limiting system according to claim 1 wherein the engine is a diesel engine. ### Claim 4 (depends on 1) A speed limiting system according to claim 1 wherein the speed signal is provided by a tachograph. ### Claim 5 (depends on 1) A speed limiting system according to claim 1 wherein the speed signal is provided by a signal generator. ### Claim 6 (depends on 1) A speed limiting ,system according to claim 1 wherein the speed signal is provided by a magnetic sensor. ### Claim 7 (depends on 1) A speed limiting system according to claim 1 wherein the fuel control means includes a fuel control valve having a solenoid energizable by the system control means to place the fuel control means in the open state. ### Claim 8 (depends on 1) A Speed limiting system according to claim 1 wherein the pressure regulator means includes a regulator valve having a solenoid energizable by the system control means to place the regulator means in the closed state. ### Claim 9 (depends on 1) A speed limiting system according to claim 1 wherein the fuel control means is always in the open state when the regulator means is in the closed state, and always in the closed state, except for limited fuel flow through the second passageway, when the regulator means is in the open state. ### Claim 10 (depends on 1) A special limiting system according to claim 1 wherein the second passageway is an orifice approximately 0.020 inch in diameter.