An air-fuel ratio control system for an internal combustion engine includes a LAF sensor and an O2 sensor arranged in an exhaust pipe at respective locations upstream and downstream of a catalytic converter. A desired air-fuel ratio coefficient used in calculating an amount of fuel supplied to the engine is calculated based on operating conditions of the engine, and corrected based on output from the O2 sensor. The air-fuel ratio of a mixture supplied to the engine is feedback-controlled to a stoichiometric air-fuel ratio based on the corrected desired air-fuel ratio coefficient. When the output from the O2 sensor falls within a predetermined range, the desired air-fuel ratio coefficient is not corrected, but held at an immediately preceding value thereof.

Air-fuel ratio control system for internal combustion engines

An internal combustion engine wherein an HC treatment catalyst (12) having the function of adsorbing the HC in the exhaust gas is arranged upstream of the NOx selective reducing catalyst (14), an urea aqueous solution fed from the reducing agent feed valve (15) is arranged upstream of the HC treatment catalyst (12), urea, and NOx contained in the exhaust gas, and HC adsorbed on the HC treatment catalyst 12 are reacted with each other to form intermediate products having cyano groups, oximes, and amino groups, and these intermediate products are sent to the NOx selective reducing catalyst (14).

Exhaust purification device of internal combustion engine

A system for controlling fuel metering in an internal combustion engine using a fluid dynamic model with the quantity of throttle-past air being determined therefrom. Based on the observation that the difference between the steady-state engine operating condition and the transient engine operating condition can be described as the difference in the effective throttle opening areas, the quantity of fuel injection is determined from the product of the ratio between the area and its first-order lag value and the quantity of fuel injection under the steady-state engine operating condition obtained by mapped data retrieval and by subtracting the quantity of correction corresponding to the quantity of chamber-filling air. A pseudo-manifold pressure is estimated and is used for calculating the effective throttle opening area and its first lag value. The pseudo-manifold pressure is corrected by atmospheric pressure, engine coolant water temperature, etc., so as to enhance estimation accuracy.

Fuel metering control system for internal combustion engine

An exhaust emission control system of an internal combustion engine capable of post injection is disclosed which provides control such that the injection timing in sub injection is set to a point earlier than the target injection timing when the sub injection is started, and the injection timing in the sub injection is then delayed to the target injection timing. This realizes the post injection under the optimum conditions and enables an efficient rise in the exhaust temperature while inhibiting deterioration of the drivability due to a rapid change in torque.

Exhaust emission control system of internal combustion engine

A method and system for fuel vapor control in a hybrid vehicle (HEV). The HEV fuel vapor recovery system includes a fuel tank isolation valve, which is normally closed to isolate storage of refueling from storage of diurnal vapors. The method for fuel vapor control includes selectively actuating the fuel tank isolation valve during interrelated routines for refueling, fuel vapor purging, and emission system leak detection diagnostics to improve regulation of pressure and vacuum the HEV fuel vapor recovery system.

Method and System for Fuel Vapor Control

An air-fuel ratio feedback control system is disclosed in which a sensing output representing the oxygen concentration in the exhaust gas of an internal combustion engine is compared with a predetermined set value. The output of the comparator is integrated and the amount of fuel injection is corrected by being increased or decreased in accordance with the integration output having an increasing or decreasing polarity so as to control the air-fuel ratio at a stoichiometrical value. At the time of engine start, the air-fuel ratio feedback control is stopped, and this condition is held after engine start. Further, the holding function is cancelled by a signal representing the activation of the detection output of the oxygen sensor.

Air-fuel ratio feedback control system

PROBLEM TO BE SOLVED: To provide a technique capable of detecting abnormality in a reduction agent feeding mechanism and to contribute to the suppression of deterioration of exhaust emission and exhaust emission purifying catalyst caused by abnormality in the reduction agent feeding mechanism in an exhaust emission control device for the internal combustion engine equipped with the mechanism feeding a reduction agent in exhaust emission purifying catalyst. SOLUTION: This exhaust emission control device for the internal combustion engine comprises a reduction agent adding nozzle arranged in an exhaust passage located upstream from the exhaust emission purifying catalyst, a reduction agent feeding passage introducing the reduction agent emitted from a reduction agent emission means to the reduction agent adding nozzle, a passage opening and closing valve provided in the reduction agent feeding passage, a pressure detection means provided in the reduction agent feeding passage located downstream from the passage opening and closing means, and an abnormality determining means for determining abnormality on the basis of pressure detected by the pressure abnormality detection means during the opening period of the passage opening and closing valve, and before and after the opening period of the valve.

Exhaust emission purifying device for internal combustion engine

In an air assist device of a fuel injection type internal combustion engine, having an air assisted injector provided close to a nozzle thereof with an adapter constituting an assist air introducing portion, in which assist air introduced into the assist air introducing portion through assist air intake ports formed in the peripheral wall of the adapter is blown out of an assist air jet formed at the bottom of the adapter together with fuel so as to facilitate the atomization of fuel, the diameter of each opening of the assist air intake ports is made smaller than the diameter of an opening of the assist air jet, the assist air intake ports are provided in a plural number, so that the total opening area of the assist air intake ports can be made larger than the opening area of the assist air jet, and/or the assist air intake ports are penetrated in directions tangential to the inner wall surface of the adapter.

Air assist device of fuel injection type internal combustion engine

An exhaust purifying apparatus for an internal combustion engine includes execution means, wherein, when an accumulation amount of particulate matter about a catalyst becomes less than a first determination value after a PM elimination control is started, the execution means executes burn-up control. Stopping means stops the PM elimination control based on an end of the burn-up control. Forcibly ending means forcibly ends the burn-up control when time elapsed since the accumulation amount of particulate matter about the catalyst has dropped to a second determination value reaches a predetermined time. Therefore, the exhaust purifying apparatus is capable of completely burning particulate matter in a PM filter, and suppresses degradation of fuel economy.

Exhaust purifying apparatus and exhaust purifying method for internal combustion engine

An air-fuel ratio control device comprising two main air-fuel ratio detecting sensors arranged in first and second exhaust passages upstream of three-way catalysts respectively for detecting an air-fuel ratio in the first and second exhaust passages, an auxiliary air-fuel ratio detecting sensor for detecting an air-fuel ratio in at least a first exhaust passage of the first and second exhaust passages downstream of the three-way catalysts, a deviation detecting unit for detecting a mutual deviation between the air-fuel ratios in the first and second exhaust passages, a first control value controlling unit for controlling a control value in at least the first cylinder bank to which the first exhaust passage is connected, on the basis of the value detected by the auxiliary air-fuel ratio detecting sensor, a second control value controlling unit for controlling a control value in at least the second cylinder bank on the basis of the deviation detected by the deviation detecting unit to cancel the deviation, a feedback correction coefficient controlling unit for controlling the feedback correction coefficients in the cylinder banks on the basis of the values detected by the corresponding main air-fuel ratio detecting sensors and the control values, and an air-fuel ratio control unit for controlling the air-fuel ratio in the first and second exhaust passages by the corresponding feedback correction coefficients to obtain a predetermined air-fuel ratio.

Hiroki Matsuoka

Papers

Air-fuel ratio feedback control system

Exhaust emission purifying device for internal combustion engine

Air assist device of fuel injection type internal combustion engine

Exhaust purifying apparatus and exhaust purifying method for internal combustion engine

Air-fuel ratio control device of an internal combustion engine