Abstract: An electric generator control apparatus of a vehicle sets respective target values of output voltage and output current for the electric generator of the vehicle, and selectively establishes a voltage control mode for holding the generator output voltage at the target voltage or a current control mode for holding the generator output current at the target current, with the mode selection and the setting of target values being performed based on criteria such as the level of charge of the vehicle battery, the electrical load of the vehicle equipment, etc.

Abstract: A control unit uses upper and lower limit guard values to limit a power generation quantity of a power generator and thereby to maintain the current combustion mode during power generation of the power generator. The control unit computes a remaining electric charge of a battery. When the remaining electric charge drops to a predetermined value or below, the control unit cancels a combustion mode maintaining operation, which maintains the current combustion mode, is cancelled, so that priority is given to the power generation of the power generator to recover the remaining electric charge of the battery. Also, when an electric power consumption in a vehicle is equal to or greater than a predetermined value, the combustion mode maintaining operation is cancelled, and the power generation quantity of the power generator is controlled in a manner that does not cause overdischarge of the battery.

Abstract: A crank angle sensor outputs a crank angle signal pulse every when a crankshaft rotates a predetermined crank angle. A time period sufficient for rotating a crankshaft between adjacent crank angle signal pulses is measured. The time period is referred to as a rotating time period. A next rotating time period between pulses including a next required ignition timing is estimated based on the rotating time period measured at a time when an engine speed is lower than a predetermined value. Then, a start timing at which a primary current begins to be supplied is set based on the next timing period.

Abstract: An engine controller controls an engine, which drives a generator, an auxiliary device, and a vehicle. The generator generates electricity, and supplying the electricity to a battery and a plurality of current consumers. A generator controller controls the generator. An auxiliary device controller controls the auxiliary device. An electric power generation calculation unit calculates one of a requested power generation of the generator and a present power generation of the generator. An engine speed changing unit evaluates tendency of power generation on the basis of the one of the requested power generation and the present power generation. The engine speed changing unit requests increase or decreases in the engine speed when the engine speed changing unit determines the power generation to be inclined toward shortage or excess.

Abstract: An air-fuel ratio sensor monitor is provided which is designed to monitor reactive characteristics or response rates of an air-fuel ratio sensor when an air-fuel ratio of a mixture to an internal combustion engine is changing to a rich side and to a lean side. The monitored response rates are used in determining whether the sensor is failing or not, in determining the air-fuel ratio of the mixture accurately, or in air-fuel ratio control of the engine.

Abstract: An increment of a fuel consumption rate caused by power generation is determined from a difference in fuel consumption rate between a case of performing power generation of an alternator and a case of stopping the power generation. The increment of the fuel consumption rate is divided by a power generation amount of the alternator to determine an increment of a fuel consumption per unit power generation amount. A use-frequency of the electric consumption is determined and also a possible power generation amount and average consumption power are calculated. A target electric consumption is set based upon the use-frequency, the possible power generation amount and the average consumption power so that the charge and discharge balance of the battery becomes zero. The present electric consumption is compared with the target electric consumption to determine whether or not to perform the power generation of the alternator.

Abstract: A generator control device controls a generator that is driven by an engine to charge a battery and supply electric power to electric loads. In the generator control device the following steps are carried out: calculating a required electric power; calculating a difference rate that is a difference in an amount of a hazardous gas component of engine exhaust gas between a first case in which the generator generates the required electric power and a second case in which the generator does not generate an electric power divided by the electric power and controlling the generator to generate the required electric power if the difference is equal to or smaller than a first reference value.

Abstract: In step 400, microcomputer 12 calculates a temperature change amount ?T1 of ignition coil FC caused by the heat generating from the ignition coil FC, based on a previous calculated temperature T(n?1) of ignition coil FC and an engine rotational speed. In step 410, the microcomputer 12 calculates a temperature change amount ?T2 of ignition coil FC caused by the heat received from the engine, based on the previous calculated temperature T(n?1) of ignition coil FC and a cooling water temperature of the engine. In step 420, the microcomputer 12 calculates a temperature change amount ?T3 of ignition coil FC caused by the heat released to the outside, based on the previous calculated temperature T(n?1) of ignition coil FC and an intake air temperature of the engine. Then, in step 430, the microcomputer 12 calculates a present ignition coil temperature T(n) based on these change amounts ?T1, ?T2, and ?T3.

Abstract: An air-fuel ratio detected by an air-fuel ratio sensor is periodically varied by executing a PI control. During the PI control, a time period in which the detected air-fuel ratio passes through a predetermined rich-side range is defined as a rich-side time constant, and a time period in which the detected air fuel ratio passes through a predetermined lean-side range is defined as a lean-side time constant. A rich-side time delay represents a time period in which an air-fuel correction amount is increasingly corrected to exceed a rich-side threshold, and a lean-side time delay represents a time period in which the air-fuel correction amount is decreasingly corrected to exceed a lean-side threshold. These time constants and time delays are compared with a determining value to diagnose degradation of an air-fuel ratio sensor.

Abstract: A crank angle sensor outputs a crank angle signal pulse every when a crankshaft rotates a predetermined crank angle. A time period sufficient for rotating a crankshaft between adjacent crank angle signal pulses is measured. The time period is referred to as a rotating time period. A next rotating time period between pulses including a next required ignition timing is estimated based on the rotating time period measured at a time when an engine speed is lower than a predetermined value. Then, a start timing at which a primary current begins to be supplied is set based on the next timing period.

Abstract: An air-fuel ratio control system has an upstream catalyst, a downstream catalyst, a first sensor for detecting a first air-fuel ratio present upstream the upstream catalyst, a second sensor for detecting a second air-fuel ratio present between the catalysts and a third sensor for detecting a third air-fuel ratio present downstream the downstream catalyst. An ECU determines a target second air-fuel ratio based on the detected third air-fuel ratio, and a target first air-fuel ratio based on the target second air-fuel ratio and the detected second air-fuel ratio. The ECU feedback controls an air-fuel ratio of mixture based on the target first air-fuel ratio and the detected first air-fuel ratio. The target first air-fuel ratio is corrected based on the detected third air-fuel ratio so that a change in the target first air-fuel ratio becomes smaller in a predetermined range other than a normal range.

Abstract: An air-fuel ratio detected by an air-fuel ratio sensor is periodically varied by executing a PI control. During the PI control, a time period in which the detected air-fuel ratio passes through a predetermined rich-side range is defined as a rich-side time constant, and a time period in which the detected air fuel ratio passes through a predetermined lean-side range is defined as a lean-side time constant. A rich-side time delay represents a time period in which an air-fuel correction amount is increasingly corrected to exceed a rich-side threshold, and a lean-side time delay represents a time period in which the air-fuel correction amount is decreasingly corrected to exceed a lean-side threshold. These time constants and time delays are compared with a determining value to diagnose degradation of an air-fuel ratio sensor.

Abstract: At a time point at which an ignition switch is made OFF and an engine is stopped, an output of a downstream gas sensor is read, thereafter, at a time point at which a predetermined time period has elapsed from stopping the engine, the output of the downstream gas sensor changed by flowing the atmosphere back into an exhaust pipe is read. Thereafter, a change in the output of the downstream gas sensor until the predetermined time period has elapsed from stopping the engine is calculated, the change in the output is compared with an abnormality determinant and when the change in the output is smaller than the abnormality determinant, response of the downstream gas sensor is determined to be abnormal.

Abstract: An emission control system has a catalyst and a sensor responding to a component of exhaust gas. In order to speed warming up the catalyst, the emission control system increases the amount of heat dissipated by exhaust gas. A diagnosis of the emission control system is carried out by determining whether the amount of heat dissipated by exhaust gas is sufficient or insufficient. The amount of heat dissipated by exhaust gas is represented by the length of time to an activated state of the sensor. In the diagnosis, the amount of heat generated by a heater provided in the sensor is taken into consideration.

Abstract: An air-fuel ratio sensor monitor is provided which is designed to monitor reactive characteristics or response rates of an air-fuel ratio sensor when an air-fuel ratio of a mixture to an internal combustion engine is changing to a rich side and to a lean side. The monitored response rates are used in determining whether the sensor is failing or not, in determining the air-fuel ratio of the mixture accurately, or in air-fuel ratio control of the engine.

Abstract: In step 400, microcomputer 12 calculates a temperature change amount ?T1 of ignition coil FC caused by the heat generating from the ignition coil FC, based on a previous calculated temperature T(n?1) of ignition coil FC and an engine rotational speed. In step 410, the microcomputer 12 calculates a temperature change amount ?T2 of ignition coil FC caused by the heat received from the engine, based on the previous calculated temperature T(n?1) of ignition coil FC and a cooling water temperature of the engine. In step 420, the microcomputer 12 calculates a temperature change amount ?T3 of ignition coil FC caused by the heat released to the outside, based on the previous calculated temperature T(n?1) of ignition coil FC and an intake air temperature of the engine. Then, in step 430, the microcomputer 12 calculates a present ignition coil temperature T(n) based on these change amounts ?T1, ?T2, and ?T3.

Abstract: When in controlling an air-fuel ratio by a feedback control, a target air-fuel ratio is changed between normal time and at rich control time, a difference between a change amount of the target air-fuel ratio and a change amount of an air-fuel ratio feedback correction coefficient is learned as a sensor error in the rich control. A final detected air-fuel ratio is calculated by correcting a detected air-fuel ratio of an air-fuel ratio sensor in rich control based on the sensor error. Alternatively, the target air-fuel ratio or the air-fuel ratio feedback correction coefficient in the rich control may be corrected based on the sensor error.

Abstract: When in controlling an air-fuel ratio by a feedback control, a target air-fuel ratio is changed between normal time and at rich control time, a difference between a change amount of the target air-fuel ratio and a change amount of an air-fuel ratio feedback correction coefficient is learned as a sensor error in the rich control. A final detected air-fuel ratio is calculated by correcting a detected air-fuel ratio of an air-fuel ratio sensor in rich control based on the sensor error. Alternatively, the target air-fuel ratio or the air-fuel ratio feedback correction coefficient in the rich control may be corrected based on the sensor error.

Abstract: At a time point at which an ignition switch is made OFF and an engine is stopped, an output of a downstream gas sensor is read, thereafter, at a time point at which a predetermined time period has elapsed from stopping the engine, the output of the downstream gas sensor changed by flowing the atmosphere back into an exhaust pipe is read. Thereafter, a change in the output of the downstream gas sensor until the predetermined time period has elapsed from stopping the engine is calculated, the change in the output is compared with an abnormality determinant and when the change in the output is smaller than the abnormality determinant, response of the downstream gas sensor is determined to be abnormal.

Abstract: If conditions for measuring a storage quantity of O2 in a catalyst are satisfied, a target air-fuel ratio is switched to a rich value after the end of a fuel-cut state. The quantity of a rich component contained in an exhaust gas flowing into a catalyst during a period of time period is calculated. The quantity of a rich component required to consume all O2 absorbed by the catalyst in the fuel-cut state is calculated. The computed quantity of a rich component is taken as a storage quantity of O2 in the catalyst. Since the air-fuel ratio of exhaust gas is changed to a rich value, to improve exhaust gas cleaning, during the computation of a storage quantity of O2, the storage quantity of O2 in the catalyst can be computed without worsening emission of exhaust gas.