Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Hisayo Dohta

Naohide Fuwa

Katsuhiko Kawai

Shigenori Isomura

Harufumi Muto

Daisuke Kobayashi

Keiji Wakahara

Makoto Miwa

Junya Morikawa

Yasuo Mukai

Masaaki Nakayama

Akira Ohata

Takeshi Fujimoto

A control apparatus for an internal combustion engine provided with a fuel supply mechanism capable of adjusting a fuel supply amount includes a flow rate sensor that detects an intake air flow rate that represents a flow rate of air admitted into a combustion chamber of the internal combustion engine, a pressure sensor that detects a pressure of the air admitted into the combustion chamber of the internal combustion engine, a characteristic change estimation unit that estimates a characteristic change of the internal combustion engine in accordance with the intake air flow rate detected by the flow rate sensor and the intake air pressure detected by the pressure sensor, and a fuel supply mechanism control unit that controls the fuel supply mechanism. The fuel supply mechanism control unit controls the fuel supply mechanism such that the characteristic change in the internal combustion engine is compensated in accordance with an estimation performed by the characteristic change estimation unit.

Control apparatus and control method for internal combustion engine

A control apparatus for controlling an internal combustion engine includes a flow rate sensor that detects an intake air flow rate that represents a flow rate of air admitted into a combustion chamber of the internal combustion engine, a pressure sensor that detects a pressure of the air admitted into the combustion chamber of the internal combustion engine, a characteristic change estimation unit that estimates a characteristic change in the internal combustion engine in accordance with the intake air flow rate detected by the flow rate sensor and the intake air pressure detected by the pressure sensor, and a control unit capable of correcting a control amount of the internal combustion engine so as to compensate the characteristic change thereof in accordance with an estimation performed by the characteristic change estimation unit. The control unit updates a correction amount representative of the control amount corrected by the control unit when the internal combustion engine is in a predetermined operation state.

In an air-fuel ratio feedback control for an engine, a cylinder-by-cylinder variation value is calculated for each cylinder based on changes of intake pipe pressure detected by an intake pipe pressure sensor, or the like, and a fuel injection amount or the like is corrected for each cylinder based on the variation value. When the variation is large during an engine operation, or until the variation correction is completed, it is determined that the output of an exhaust gas sensor will be disturbed by the variation and an air-fuel ratio feedback correction amount will be disturbed. Therefore, a control gain of the air-fuel ratio feedback control is changed to a value smaller than a normal value, or the feedback control is inhibited.

Engine control apparatus having cylinder-by-cylinder feedback control

A fuel transportation lag model has a fuel transportation lag element A (FTLEA) due to adhesion of an injected fuel onto wall faces and a first-order lag element B (FOLEB) for compensating a model error of the (FTLEA). A fuel correction amount has a (FTLEA) compensation term and a (FOLEB) compensation term. By a compensation term for the (FTLEA), a first wall adhesion correction amount is obtained by multiplying a deviation between the wall face adhesion fuel amount (WFAFA) in a steady driving mode and a (WFAFA) at a present time with a first reference adaptation parameter and a first correction factor. By a compensation term for the (FOLEB), a second wall adhesion correction amount is obtained by multiplying a deviation between a required fuel amount of a present time and a required fuel amount of last time with a second reference adaptation parameter and a second correction factor.

Fuel injection amount control system for internal combustion engine

For a control model which simulates a control object ranging from the fuel injection valve up to the air-fuel ratio sensor, coefficients of a characteristic polynomial of the control model are calculated based on the pole arrangement scheme, with roots equal in number to the dead time of the control model being made 0, control parameters are calculated from the coefficients of the characteristic polynomial and from model parameters, and the air-fuel ratio correction factor is calculated from the control parameters. The control model is expressed in terms of a dead time plus first-order lag system, with the total number of roots being set greater by two than the number n of roots which are derived from the time lag, and unknown roots other than those of the dead time are solved based on formulas which are expressed in terms of a second-order lag system.

Air-fuel ratio controller of internal combustion engines

Flow amount calculation controller and flow amount calculation control method

An internal combustion engine is simulated as a control model that covers from a fuel injection point to an air-fuel ratio detection point. A response time constant of the control model is calculated as a continuous function of the amount of intake air, and a control gain of the control model is calculated as a continuous function of the response time constant. Control parameters of the control model are calculated using a calculation interval, the response time constant, an attenuation coefficient and the control gain. Thus, the control parameters are varied continuously in response to changes in the intake air amount. The air-fuel correction coefficient is calculated using the control parameters a , a , a , b and b as well as a deviation of an actual air-fuel ratio from a target air-fuel ratio. The amount of fuel supplied to the engine is calculated using the air-fuel ratio correction coefficient.

Air-fuel ratio control system and method using control model of engine

When a diagnosis execution condition is established, a canister closure valve is closed, thereafter, a purge control valve is opened, a purge control valve is closed in a state where negative pressure is introduced into an evaporated gas system to thereby maintain the evaporated gas system in a hermetically-sealed state and the hermetically-sealed state is continued until abnormality diagnosis is finished. Time period for maintaining the evaporated gas system in the hermetically-sealed state is divided into three time periods of a pressure change determining time period at a first time, an awaiting time period and a pressure change determining time period at a second time. After determining a pressure change amount DPT1 of the evaporated gas system in the pressure change determining time period at the first time, the evaporated gas system is successively maintained in the hermetically-sealed state, after the predetermined awaiting time period has elapsed, the pressure change determination at the second time is carried out by which a pressure change amount DPT2 of the evaporated gas system is determined. Further, presence or absence of leakage of the evaporated gas system is diagnosed by comparing the pressure change amount DPT1 at the first time with the pressure change amount DPT2 at the second time.

Abnormality detection apparatus for preventing fuel gas emission

An inflow quantity of an exhaust gas component flowing into a catalyst is calculated based upon air fuel ratio detected by an upstream air fuel ratio sensor which is provided on the upstream side of the catalyst. In addition, an outflow quantity of an exhaust gas component flowing out of the catalyst is calculated based upon air fuel ratio detected by a downstream air fuel ratio sensor which is provided on the downstream side of the catalyst. The quantity of an exhaust gas component absorbed by the catalyst can be detected in real time based upon a difference between the inflow quantity and outflow quantity. Thus, a state of the catalyst can be precisely detected in real time.

Abnormality detector for air-fuel ratio control system

An air-fuel ratio control apparatus for an internal combustion engine is provided which includes an air-fuel ratio determining circuit which determines an air-fuel ratio of exhaust gases flowing upstream of a catalytic converter for controlling the air-fuel ratio of the exhaust gases so as to agree with a target air-fuel ratio under feedback control, a sorbed substance amount determining circuit for determining the amount of substances sorbed in the catalytic converter, and a target air-fuel ratio determining circuit for determining said target air-fuel ratio so that the amount of substances determined by said sorbed substance amount determining means falls within a given range. The sorbed substance amount determining circuit determines the amount of substances sorbed in the catalytic converter based on the air-fuel ratio determined by said air-fuel ratio determining circuit using a catalytic converter model established using parameters indicating adsorption reaction of exhaust gas components entering the catalytic converter, oxidation-reducing reaction of the substances sorbed in the catalytic converter with the exhaust gas components, desorption reaction of the substances sorbed in the catalytic converter, and a non-reacted portion of the exhaust gas components.

Air-fuel ratio control system for internal combustion engine

A fuel supply amount control apparatus improves controllability during engine acceleration and deceleration and immediately after starting the operation of the engine, by enabling the setting of suitable parameters. An evaporation time constant indicating chronological changes in the fuel amount introduced into a cylinder from an intake system of the engine is computed by a predetermined computation equation. During this computation, the computation load is reduced by using an Aquino operator .alpha. and a stroke interval Aquino operator A.alpha. and computation for computing the fuel injection amount is executed at an interval shorter than the interval of two successive fuel injections, e.g., a crank angle of 60.degree.. During computation of the evaporation time constant, the evaporation time constant after full warm-up is corrected based on an average temperature weighted according to an adherence rate of fuel to the intake manifold and intake valve. The intake valve temperature, since it increases according to input heating energy, is estimated from the injected fuel amount.

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Chiryu, Japan

Hisayo Dohta