Engine control with function to eliminate minute particles in exhaust gas

Claim 1

A method of controlling an internal combustion engine having a function of eliminating minute particles in exhaust gas by using a fuel injection valve which is provided in the internal combustion engine and in which a fuel injection timing is controlled, a filter temperature sensor, inserted in an exhaust path, for measuring a temperature of a filter for trapping minute particles in exhaust gas, and an electric heater for removing minute particles deposited on the filter by combustion, said method comprising the steps of: detecting a filter condition of particle deposition on said filter for which a restoration of a filtering function is required; generating a preheating instruction for preheating the filter by raising a filter temperature when said filter condition is detected; generating a signal for changing, based on said filter preheating instruction, an injection pattern of the fuel injection valve for preheating the filter; determining based on a signal from said filter temperature sensor, whether or not said preheating for raising the filter temperature is completed; energizing said electric heater to combust particles on the filter, based on a condition of preheating of said filter; and releasing the filter preheating mode after said energization of said electric heater.

Claim 2

A method of controlling an internal combustion engine having a function of eliminating minute particles in exhaust gas by using a fuel injection valve which is provided in the internal combustion engine and in which a fuel injection timing is controlled, a filter temperature sensor, inserted in an exhaust path, for measuring a temperature of a filter for trapping minute particles in exhaust gas, and an electric heater for removing minute particles deposited on the filter by combustion, said method comprising the steps of: detecting a filter condition of particle deposition on said filter for which a restoration of a filtering function is required; generating a preheating instruction for preheating the filter by raising a filter temperature when said filter condition is detected; generating a signal for changing, based on said filter preheating instruction, an injection pattern of the fuel injection valve for preheating the filter; determining based on a signal from said filter temperature sensor, whether or not said preheating for raising the filter temperature is completed; energizing said electric heater to combust particles on the filter, based on a condition of preheating of said filter; and releasing the filter preheating mode after said energization of said electric heater.

Claim 10

A system for eliminating minute particles in exhaust gas comprising: a fuel injection valve in which a fuel injection pattern of said engine is controlled, by controlling a valve open/close operation by an electrical pulse signal; fuel pump means for constantly supplying an upstream side of said fuel injection valve with a high pressure fuel; a heatproof filter inserted in an exhaust path for trapping minute particles in exhaust gas; differential pressure sensor means for measuring a pressure difference between an upstream side and a downstream side of said filter; filter temperature sensor means, inserted in the exhaust path, for measuring a temperature of said filter; and an electric heater arranged close to the upstream side of said filter, for eliminating by combustion minute particles deposited on said filter; and control means for: (a) determining the necessity for restoration of a filtering ability of said filter based on the signal from said differential pressure sensor means; (b) selectively commanding a preheating operation for raising the filter temperature based on said determining function (a); (c) instructing an injection of fuel by delivering a signal for changing a valve open/close pattern for filter preheating based on said preheating operation; (d) determining whether a preheating for raising the filter temperature is completed based on the signal from the filter temperature sensor means; (e) instructing a combustion of minute particles in the filter by supplying an electric power to the electric heater for eliminating minute particles in the filter when said filter is preheated.

Claim 11

A system for eliminating minute particles in exhaust gas comprising: a fuel injection valve in which a fuel injection pattern of said engine is controlled, by controlling a valve open/close operation by an electrical pulse signal; fuel pump means for constantly supplying an upstream side of said fuel injection valve with a high pressure fuel; a heatproof filter inserted in an exhaust path for trapping minute particles in exhaust gas; differential pressure sensor means for measuring a pressure difference between an upstream side and a downstream side of said filter; filter temperature sensor means, inserted in the exhaust path, for measuring a temperature of said filter; and an electric heater arranged close to the upstream side of said filter, for eliminating by combustion minute particles deposited on said filter; and control means for: (a) determining the necessity for restoration of a filtering ability of said filter based on the signal from said differential pressure sensor means; (b) selectively commanding a preheating operation for raising the filter temperature based on said determining function (a); (c) instructing an injection of fuel by delivering a signal for changing a valve open/close pattern for filter preheating based on said preheating operation; (d) determining whether a preheating for raising the filter temperature is completed based on the signal from the filter temperature sensor means; (e) instructing a combustion of minute particles in the filter by supplying an electric power to the electric heater for eliminating minute particles in the filter when said filter is preheated.