# US 5,699,772 A · Fuel supply system for engines with fuel pressure control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,699,772 A - Document ID: US5699772A - Status: Granted - Kind: A - Application number: 08/577,928 - Filed: 1995-12-22 - Granted: 1997-12-23 - Earliest claimed: 1995-01-17 - Assignees: Nippondenso Co., Ltd. - Inventors: Masao Yonekawa; Yoshihiro Majima; Makoto Miwa; Kazuji Minagawa; Kiyotoshi Oi - Web page: https://patentgrep.com/patent/US5699772A ## CPC - F02D 41/32: of the low pressure type {(F02D41/3082 takes precedence)} - F02D 41/3082: {Control of electrical fuel pumps} - F02M 37/08: electrically driven - F02M 69/462: {Arrangement of fuel conduits, e.g. with valves for maintaining pressure in the pipes after the engine being shut-down} - F02M 69/465: {of fuel rails} - F02D 2200/0602: Fuel pressure - F02D 2250/02: Fuel evaporation in fuel rails, e.g. in common rails - F02D 2250/31: Control of the fuel pressure - F02M 2037/087: {Controlling fuel pressure valve} - 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 ## Abstract In a fuel supply system of an internal combustion engine, an actual fuel pressure Pf is measured by a differential pressure sensor and the actual fuel pressure Pf is averaged in a different degree to determine two kinds of values Pfs and Pft. The value Pfs is used to control the fuel pressure, while the value Pft is used to correct a pulse width. Then, a correction value Vfpci is determined according to the load applied to the engine and used in a feedback control to adjust a fuel discharge pressure of a fuel pump. ## Claims ### Claim 1 A fuel supply system of an internal combustion engine for feeding, under pressure, fuel stored inside a fuel tank by means of a fuel pump to an injector through a fuel pipe and a fuel filter and injecting the fuel to the internal combustion engine from the injector, the system comprising: a speed variable driving means for speed-variably controlling a discharge pressure of the fuel pump; a fuel pressure detection means positioned downstream the fuel filter for detecting a fuel pressure inside the fuel pipe; a pulse width correction means for correcting a width of a pulse to be applied to the injector, according to the fuel pressure detected by the fuel pressure detection means; and a fuel pressure control means for controlling the speed-variable driving means by feedback, based on the fuel pressure detected by the fuel pressure detection means so that the fuel pressure coincides with a target-pressure, the fuel pressure control means including a means for correcting a correction value to be used to control the speed-variable driving means by the feedback, according to a load applied to the internal combustion engine. ### Claim 2 (depends on 1) The fuel supply system of the internal combustion engine according to claim 1, wherein the fuel pressure control means controls the speed-variable driving means and the pulse width correction means corrects the pulse width, based on an average value of the fuel pressures detected by the fuel pressure detection means. ### Claim 3 (depends on 2) The fuel supply system of the internal combustion engine according to claim 2, wherein the average value of the fuel pressures detected by the fuel pressure detection means is set differently by averaging in different degrees to be used to control the speed-variable driving means and to be used to correct the pulse width. ### Claim 4 (depends on 1) The fuel supply system of the internal combustion engine according to claim 1, wherein the fuel pipe is in a nonreturn-type construction terminating with a delivery pipe for distributing the fuel to the injector. ### Claim 5 A fuel supply system of an internal combustion engine comprising: a fuel supply means for feeding fuel via a fuel supply pipe; a fuel pressure detection means for detecting a pressure of the fuel present inside the fuel supply pipe; a fuel injection means for injecting the fuel supplied thereto via the fuel supply pipe to each cylinder of the internal combustion engine by opening and closing a fuel injection valve synchronously with the rotation of the internal combustion engine; a pressure fluctuation calculation means for calculating a fluctuation amount of the pressure detected by the fuel pressure detection means when the fuel injection valve is opened or closed by the fuel injection means; and a gas presence/absence decision means for deciding whether gas is present in the fuel supply pipe, based on the fluctuation amount of the pressure calculated by the pressure fluctuation calculation means. ### Claim 6 (depends on 5) The fuel supply system of the internal combustion engine according to claim 5, wherein the fuel supply means increases the pressure of fuel when the gas presence/absence decision means decides that gas is present in the fuel supply pipe. ### Claim 7 (depends on 5) The fuel supply system of the internal combustion engine according to claim 5, wherein the number of the fuel injection valves is plural; and the fuel injection means increases the number of the fuel injection valves which are opened simultaneously when the gas presence/absence decision means decides that gas is present in the fuel supply pipe.