Abstract: A diagnostic device and method of an engine exhaust purifying system, which perform active control of an air-fuel ratio and can make diagnosis of air-fuel ratio sensors, catalysts, etc. in the engine exhaust purifying system with high accuracy and reliability while avoiding a worsening of exhaust emissions, an increase of revolution variations, etc.

Abstract: An engine controller comprises a combustion state detection or estimation means for detecting or estimating a combustion state in the combustion chamber, a combustion air-fuel ratio estimation means for estimating a combustion air-fuel ratio in the combustion chamber according to an exhaust air-fuel ratio and the detected or estimated combustion state, and a means for calculating engine control parameters according to the estimated combustion air-fuel ratio.

Abstract: An internal combustion engine controller, is used with a fuel-based torque-on-demand control type, multi-cylinder, direct-injection internal combustion engine, to provide an air flow rate control that excels in response and convergence. The internal combustion engine controller includes a section for computing a target throttle opening from operating conditions, which in turn includes a first computing section for determining a target throttle opening by feedback control in accordance with operating conditions including an intake air flow rate; a second computing section for determining a target throttle opening by feed-forward control in accordance with operating conditions; and a third computing means for determining a target throttle opening based on the target throttle opening value determined by the first computing means and the second computing means.

Abstract: A diagnostic device and method of an engine exhaust purifying system, which perform active control of an air-fuel ratio and can make diagnosis of air-fuel ratio sensors, catalysts, etc. in the engine exhaust purifying system with high accuracy and reliability while avoiding a worsening of exhaust emissions, an increase of revolution variations, etc.

Abstract: The invention provides an engine controller, which can determine a deterioration mode (gain deterioration or response deterioration) of an air/fuel (A/F) ratio sensor, can detect a degree of the deterioration with high accuracy, and can optimize A/F ratio feedback control in accordance with the diagnosis result. The controller includes a unit for computing frequency response characteristics in a range from an A/F ratio adjusting unit to the A/F ratio sensor, and it diagnoses the A/F ratio sensor based on a gain characteristic and a response characteristic given by the computed frequency response characteristics. In accordance with the diagnosis result, parameters (P- and I-component gains) used in A/F ratio feedback control (PI control) are optimized.

Abstract: Pressure detection means detects the pressure of an evaporation purge system that includes a fuel tank and a communicating tube, which connects a canister for adsorbing and retaining fuel vapor to an intake pipe. Shutout means shuts out the evaporation purge system from atmospheric air. A pump is driven for pressurization or depressurization purposes while the shutout means shuts out the evaporation purge system from atmospheric air. The pump is stopped when the pressure detected by the pressure detection means reaches a predetermined level. A leak judgment is formulated in accordance with pump drive time and a pressure change after pump stoppage.

Abstract: An engine control apparatus which can ensure and maintain a stability and constant exhaust emission characteristics even in such a condition that a nature of a fuel used as present is unsure, and which is robust among different fuel natures, comprising a plurality of different nature fuel quantity computing means and an operating condition detecting means for detecting an operating condition of an engine, wherein a first nature fuel quantity computing means among the plurality of different nature fuel quantity computing means is used as a fuel quantity computing means during an engine start, and the first nature fuel quantity computing means is forcibly changed over into a second nature fuel quantity computing means if an engine operating condition detected by the operating condition detecting means satisfies a predetermined term.

Abstract: An internal combustion engine control device for, in a lean-burn internal combustion engine provided with a three-way catalyst and a lean NOx catalyst in an exhaust system, optimizing an air/fuel ratio in a rich mode from the viewpoints of both better fuel economy and exhaust emission control when NOx having been stored in a lean NOx catalyst during a lean operation is desorbed and cleaned by switching to a rich operation. An internal combustion engine control device for controlling an air/fuel ratio during the rich operation to be changed between a period of desorbing O2 stored in the three-way catalyst and a period of desorbing and cleaning NOx stored in the lean NOx catalyst.

Abstract: A first, a second, and a third combustion region are defined by the air-fuel ratio of the mixture gas feeding combustion. Upon switching of combustion regions from the first combustion region to the third combustion region and from the third combustion region to the first combustion region, namely, when the second combustion region is passed, the mass of NOx emission downstream of an exhaust purifying device and the torque variation are estimated online. Based on the estimated value of the mass of NOx emission and the estimated value of the torque variation, the mass of intake air introduced into the combustion chamber is adjusted in a manner different from when normal, such as by changing the amount of lift of the intake valve, for example, so as to reduce the mass of NOx emission downstream of the exhaust purifying device and the torque variation below predetermined values upon passing of the second combustion region.

Abstract: The invention provides an engine controller, which can determine a deterioration mode (gain deterioration or response deterioration) of an air/fuel (A/F) ratio sensor, can detect a degree of the deterioration with high accuracy, and can optimize A/F ratio feedback control in accordance with the diagnosis result. The controller includes a unit for computing frequency response characteristics in a range from an A/F ratio adjusting unit to the A/F ratio sensor, and it diagnoses the A/F ratio sensor based on a gain characteristic and a response characteristic given by the computed frequency response characteristics. In accordance with the diagnosis result, parameters (P- and I-component gains) used in A/F ratio feedback control (PI control) are optimized.

Abstract: An apparatus and a method of control of the engine for separating and detecting the fuel remaining in the engine and in the intake passages before the start of the engine and also detecting the fuel property, and calculating a parameter such as an optimum fuel injection quantity when the engine is started, and thus enabling an efficient exhaust performance and a good running performance to be compatible at start-up. The engine control apparatus has a unit for detecting or estimating a burned fuel quantity of the engine, and a unit for separating and detecting a burned fuel quantity supplied from the fuel injection valve and a burned quantity of fuel other than the fuel supplied from the injection valve.

Abstract: A control apparatus is capable of separately detecting an unexpected fluctuation in the amount of NOx discharged from an engine (combustion chamber), separately from deterioration of lean NOx catalyst performance, thereby avoiding incorrect diagnosis of deterioration of the lean NOx catalyst, and ensuring the optimum control of the catalyst.

Abstract: In a lean-burn engine equipped, in the exhaust pipe, with NOx trap catalyst that collects NOx by absorption or occlusion, the rich spike start timing and rich spike volume are optimized. The above subject is achieved by an engine control system equipped, in the downstream side of the NOx trap catalyst, with a NOx sensor that detects the NOx component in the exhaust, NOx trap catalyst model, and a device that controls the engine operating condition based on the outputs of the NOx trap catalyst model and NOx sensor.

Abstract: An internal combustion engine controller for automobiles which realizes torque increasing performance and exhaust gas purifying performance in a well-balanced manner even when a high-response torque increase is demanded in uniform charge stoichiometric combustion which is operated at a value close to the theoretical air-fuel ratio in torque base type engine control. The internal combustion engine controller comprises target torque computation means for computing the target torque based on the demand torque of the internal combustion engine such as the operation quantity of an accelerator, means of computing the target throttle angle based on the target torque, and torque assist control means for assisting torque based on the state of the target torque and the operation state of the internal combustion engine. The above torque assist control means carries out torque assist control by increasing the quantity of fuel when a torque increase is demanded.

Abstract: An engine control equipment capable of activating a catalyst and preventing exhaust gas from deteriorating in order to early perform combustion by compressive self-ignition is disclosed. The engine control equipment is an engine control equipment including a catalyst for burning a mixed gas in a combustion chamber by compressive self-ignition and purifying exhaust-gas components in the combustion chamber and a controller for controller the catalyst which determines the activation of the catalyst and activates the catalyst in accordance with a determination result based upon determining the activation of the catalyst.

Abstract: A control apparatus operates a compression ignition internal combustion engine by switching between spark ignition combustion using an ignition device and compression ignition combustion which self-ignites a mixture by piston compression. Variable valve mechanisms vary at least one of the valve timings and valve lifts of an intake valve and an exhaust valve. Intake air is regulated to vary the amount of air intake into a combustion chamber on the upstream side of a combustion chamber inlet of the compression ignition internal combustion engine. The variable valve mechanisms and the intake air regulation are controlled during the compression ignition combustion so as to perform the compression ignition combustion.

Abstract: An internal combustion engine control device for, in a lean-burn internal combustion engine provided with a three-way catalyst and a lean NOx catalyst in an exhaust system, optimizing an air/fuel ratio in a rich mode from the viewpoints of both better fuel economy and exhaust emission control when NOx having been stored in a lean NOx catalyst during a lean operation is desorbed and cleaned by switching to a rich operation. An internal combustion engine control device for controlling an air/fuel ratio during the rich operation to be changed between a period of desorbing O2 stored in the three-way catalyst and a period of desorbing and cleaning NOx stored in the lean NOx catalyst.

Abstract: In order to improve the decrease of the catalytic action and the deterioration of the exhaust purification performance, a catalyst installed in the exhaust pipe of an engine and a secondary air pump for supplying secondary air into the exhaust pipe are provided, and the secondary air pump is operated even after the engine has stopped.

Abstract: Pressure detection means detects the pressure of an evaporation purge system that includes a fuel tank and a communicating tube, which connects a canister for adsorbing and retaining fuel vapor to an intake pipe. Shutout means shuts out the evaporation purge system from atmospheric air. A pump is driven for pressurization or depressurization purposes while the shutout means shuts out the evaporation purge system from atmospheric air. The pump is stopped when the pressure detected by the pressure detection means reaches a predetermined level. A leak judgment is formulated in accordance with pump drive time and a pressure change after pump stoppage.

Abstract: An engine control system, which is adaptable for individual differences among engines, changes with time, environmental changes, etc., and which can control engine torque with high accuracy and high response. The engine control system comprises a unit for detecting engine torque in at least one of direct and indirect manners, a unit for computing an engine control parameter, and a unit for modifying the engine control parameter based on the detected torque detected by the engine torque detecting unit.