Abstract: A purge control unit opens the purge control valve to supply, as purge gas to an intake passage, the evaporative fuel together with air in response to a predetermined purge request. An air-fuel ratio detection unit detects an air-fuel ratio of the internal combustion engine. A concentration learning unit estimates a fuel concentration in the purge gas based on a change in the air-fuel ratio when the purge control unit causes the purge gas to be supplied to the intake passage and to perform a fuel concentration learning to update a concentration learning value, which is a learning value of the fuel concentration in the purge gas, based on the estimated fuel concentration. An injection control unit corrects a fuel injection amount based on the concentration learning value in a period in which the concentration learning unit performs the fuel concentration learning in the lean combustion operation.

Abstract: Methods and systems are provided for adjusting a compression ratio of a variable compression ratio (VCR) engine during engine shutdown. In one example, a method (or system) may include actuating a VCR mechanism from a higher compression ratio setting to a lower compression ratio setting after a last combustion event and before the engine spins down to rest. In this way, engine shake, for example, due to piston bounce-back, may be reduced.

Abstract: In a control apparatus for use an internal combustion engine in which warming-up time air fuel ratio control is executed, the air fuel ratio of the exhaust gas flowing into the three-way catalyst is changed to an air fuel ratio higher by the predetermined amount, by using as a trigger the timing at which a measured value of an air fuel ratio sensor indicates a rich air fuel ratio. In addition, when the timing at which the measured value of the air fuel ratio sensor indicates the rich air fuel ratio is earlier than a reference timing, the starting-time-rich-air-fuel-ratio in the next and following warming-up time air fuel ratio control is corrected to an air fuel ratio which is higher than that in the current warming-up time air fuel ratio control.

Abstract: Disclosed is a control device applied to an internal combustion engine provided with a fuel vapor treatment system for treating collected fuel vapor by purging the collected fuel vapor into intake air downstream from an air flowmeter (6) and an exhaust gas recirculation system for recirculating part of exhaust gas in the intake air using intake negative pressure. An electronic control unit (22) performs an advance correction corresponding to the exhaust gas recirculation quantity regarding the MBT ignition timing and the knock limit ignition timing, and corrects the volumetric efficiency of the internal combustion engine, which is used for the calculation of the advance correction quantity used for the advance correction, according to the purge air quantity.

Abstract: A method for monitoring the enabling of a system which is assigned to an internal combustion engine, in which the readiness for operation of the system is dependent on an operating temperature, is characterized in that a fault in the enabling of the system is inferred (106) if operation of the system cannot be detected on expiry of a predeterminable time period after the starting of the internal combustion engine or on the recurrence of readiness for operation.

Abstract: In an apparatus for controlling a general-purpose engine used as a prime mover of an operating machine, the apparatus regulating a throttle opening such that an engine speed is converged to a desired engine speed, calculating a basic fuel injection amount based on the engine speed and throttle opening, and controlling engine warm-up operation by correcting the basic fuel injection amount with a correction coefficient to calculate a warm-up time fuel injection amount after engine start is completed and injecting fuel by the calculated amount, a fuel injection amount with which the engine output becomes maximum is searched based on the throttle opening regulated in response to increase/decrease operation of the warm-up time fuel injection amount conducted when the engine speed is constant; and the correction coefficient is corrected using the searched fuel injection amount. With this, a warm-up correction coefficient appropriate for the engine warm-up condition can be calculated.

Abstract: A system for calibrating a response to an exhaust-stream NOx level in a motor vehicle is provided. The system comprises a NOx sensor that includes an electrode, a current from the electrode responsive to the exhaust-stream NOx level while a bias voltage is applied to the electrode. The system further comprises a controller configured to interrupt the bias voltage and to adjust a motor-vehicle response to the current based at least partly on an attained voltage of the electrode while the bias voltage is interrupted. Other embodiments provide a method of calibrating a NOx sensor response in terms of gain and offset parameters.

Abstract: A sensor control apparatus includes: a gas sensor including an oxygen concentration detection cell having a first solid electrolyte body, a reference electrode and a detection electrode, and a heater; an electric current supply unit that supplies electric current to the oxygen concentration detecting cell; an activation determination unit; a heater control unit that sets a first target temperature equal to or higher than an activation determination temperature when the activation determination unit determines that the temperature of the gas sensor is equal to or higher than the activation determination temperature; an automatic stop detection unit; and a first temperature switching unit that controls electric current supplied to the heater such that the target temperature of the heater is switched to a second target temperature different from a temperature at which blackening is generated in the first solid electrolyte body when an automatic stop is detected.

Abstract: In a method for heating a gas sensor (1), in particular an exhaust gas sensor for an exhaust system (5) of a motor vehicle (7), a temperature of the gas sensor (1) is determined and the heating process is influenced as a function of the temperature.

Abstract: Provided is a control device for an engine which is capable of purifying NOx with high efficiency at a restart after an idle stop without deteriorating purification efficiency of HC and CO. At the restart after the idle stop, an air-fuel ratio is controlled to be rich, and an atmosphere inside of a catalyst is estimated on the basis of a required time ?T from a time point at which an output value (VO2—2) of first oxygen concentration detection means upstream of the catalyst exceeds a predetermined value A1 to a time point at which an output value (VO2—2) of second oxygen concentration detection means downstream of the catalyst exceeds a predetermined value A2, whereby an air-fuel ratio at next and subsequent restarts is corrected so that the atmosphere inside of the catalyst is optimized at the next and subsequent restarts.

Abstract: A method is provided for controlling an engine having two cylinders, one of which having an adjustable valve. The method comprising performing a combustion in two cylinders having pistons, the combustions for said cylinders occurring during a common stroke of the pistons; increasing a number of strokes in a cycle of one of the two cylinders; and returning operation of the one of the two cylinders to four strokes, so that combustion of the one of the two cylinders occurs sequentially from the other of the two cylinders.

Abstract: A method for improving starting of an engine that may be operated with fuels having varying alcohol concentrations is presented. In one embodiment, the method adjusts a compression ratio of an engine in response to a number of combustion events after an engine stop and a concentration of alcohol in a fuel supplied to the engine. The method may make engine starting more repeatable at lower engine temperatures.

Abstract: In a diesel engine 10 equipped with a fuel injection device 50 having a fuel supply pump 53 for pressingly sending a fuel, a common rail 52 for accumulating the fuel pressingly sent from the fuel supply pump, injectors 51 for injecting the fuel into a cylinder by an electronic control, a coolant water temperature sensor 64 for detecting an engine coolant water temperature and a fuel injection quantity map for calculating a target common rail pressure, total amount of injections, the number of multistage injection, the respective injection quantity and the respective injection quantity timing, the diesel engine 10 comprises a total injection quantity increasing means for increasing the total amount of injections in the injection quantity control arithmetic means and an injection number reduction avoidance means for avoiding that the number of multistage injections are changed by the total injection quantity increasing means when the engine is transferred to a cold state to a warming state.

Abstract: A heating module for an oxygen sensor comprises an estimated mass module, a cumulative mass module, and a temperature control module. The estimated mass module determines an estimated mass of intake air to remove condensation from an exhaust system after startup of an engine. The cumulative mass module determines a cumulative mass of intake air after the engine startup. The temperature control module adjusts a temperature of an oxygen sensor measuring oxygen in the exhaust system to a first predetermined temperature after the engine startup and adjusts the temperature to a second predetermined temperature when the cumulative air mass is greater than the estimated air mass, wherein the second predetermined temperature is greater than the first predetermined temperature.

Abstract: A method of operation of an internal combustion engine including an intake valve coupled to a combustion chamber, and a port fuel injector positioned upstream of the intake valve in an intake manifold including a throttle, the port fuel injector fluidly coupled to a fuel rail included in a fuel delivery system housing a fuel at least partially composed of alcohol. The method including, during a start-up operation when the temperature of the engine is below a threshold value and fuel is actively being injected into the intake manifold, adjusting a cone angle of a fuel spray from the port fuel injector, via adjustment of the throttle and/or fuel delivery system, based on the position of the intake valve.

Abstract: A system for calibrating a response to an exhaust-stream NOx level in a motor vehicle is provided. The system comprises a NOx sensor that includes an electrode, a current from the electrode responsive to the exhaust-stream NOx level while a bias voltage is applied to the electrode. The system further comprises a controller configured to interrupt the bias voltage and to adjust a motor-vehicle response to the current based at least partly on an attained voltage of the electrode while the bias voltage is interrupted. Other embodiments provide a method of calibrating a NOx sensor response in terms of gain and offset parameters.

Abstract: A fuel control system includes a pressure comparison module that generates a pressure control signal when a fuel supply pressure is greater than a predetermined pressure value, a temperature comparison module that generates a temperature control signal when a temperature of an engine is greater than a predetermined temperature value, and a pre-crank fuel module that selectively dispenses pre-crank fuel prior to cranking the engine based on the pressure control signal and the temperature control signal. A related fuel control method is also provided.

Abstract: An air-fuel ratio sensor early activation feedback system and method includes an air-fuel ratio sensor for measuring an air-fuel ratio in an exhaust gas generated by an internal combustion engine and a heater for heating the air-fuel ratio sensor. A controller activates the heater prior to startup of the engine based on prior startup times for the engine.

Abstract: A method for controlling an internal combustion engine that is to be operated either by petrol or alcohol or by a variable proportion of the two fuels and that includes an electronic control unit that can drive the engine, an admission line, and an exhaust line that includes a richness probe. The method determines the richness of the carbide mixture entering into the combustion cylinders, and increases the duration of the injection by intervals according to the richness of the carbide mixture.

Abstract: In at least a first cycle at startup, an opening timing of an exhaust valve is controlled to 45 degrees before-bottom-dead-center of an exhaust stroke, or to a retard side of the normal closing timing that is set after warm-up is complete. Also, the closing timing of the exhaust valve is preferably controlled to an advance side of top-dead-center in a second cycle at startup and thereafter at the latest. Accordingly, the amount of unburned HC discharged during a cold start of an internal combustion engine is reduced.

Abstract: An air-fuel ratio control system includes an air-fuel ratio sensor (23, 24) disposed upstream or downstream of an exhaust purification catalyst, and performs feedback control of the fuel supply amount such that an output value of the air-fuel ratio sensor is controlled to the target air-fuel ratio. The feedback control is performed by calculating a correction amount by summing up the value of a proportional and the value of an integral calculated based on the deviation between the output value of the air-fuel ratio sensor and the target air-fuel ratio, and correcting the fuel supply amount based on the obtained correction amount. At cold startup of the internal combustion engine, the value of the integral is set to be a smaller value from the startup of the internal combustion engine until a predetermined period elapses.

Abstract: A method comprises operating an engine of a vehicle to provide output torque to an input of a torque converter, determining whether the engine is in a cold start condition, fixing an input shaft of a transmission when the engine is in the cold start condition, and coupling the input shaft of the transmission to an output of the torque converter. A control module comprises a combustion control module that operates an engine of a vehicle to provide output torque to an input of a torque converter, a NPD module that determines whether the engine is in a cold start condition, and a transmission control module that fixes an input shaft of a transmission when the engine is in the cold start condition, wherein the input shaft of the transmission is in communication with an output of the torque converter.

Abstract: A fuel injection control device of an internal combustion engine capable of using multiple kinds of fuel includes an ECU with a ROM for storing multiple reference fuel injection quantity maps corresponding to mixture concentrations of the multiple kinds of fuels. A control program of the CPU stores which of the multiple reference fuel injection quantity map is used out of the maps in an EEP-ROM, performs starting control of an engine using the reference fuel injection quantity map which is used immediately before stopping previous time at the time of initiating the starting based on the stored maps and, at the same time, performs the starting control by gradually increasing the fuel injection quantity until the starting of an engine is finished. As a result, control of fuel supply is optimized in response to mixing different kinds of fuels, and the engine starting time is shortened.

Abstract: An air-fuel ratio control system includes an air-fuel ratio sensor (23, 24) disposed upstream or downstream of an exhaust purification catalyst, and performs feedback control of the fuel supply amount such that an output value of the air-fuel ratio sensor is controlled to the target air-fuel ratio. The feedback control is performed by calculating a correction amount by summing up the value of a proportional and the value of an integral calculated based on the deviation between the output value of the air-fuel ratio sensor and the target air-fuel ratio, and correcting the fuel supply amount based on the obtained correction amount. At cold startup of the internal combustion engine, the value of the integral is set to be a smaller value from the startup of the internal combustion engine until a predetermined period elapses.

Abstract: A failure diagnostic apparatus is provided with an offset power source for offsetting a ground-side voltage of an air-fuel ratio sensor, an activation state judging unit for judging whether the air-fuel ratio sensor is active, a failure diagnosing unit for judging for a failure from an offset-added output signal of the air-fuel ratio sensor in a period when the activation state judging unit judges that the air-fuel ratio sensor is active, an input resistance switching unit for switching the level of an input signal from the air-fuel ratio sensor when the failure diagnosing unit has detected a failure in the air-fuel ratio sensor, and a failure state judging unit for determining a type of failure of the air-fuel ratio sensor on the basis of a voltage level obtained when the input resistance switching unit has switched the input signal level.

Abstract: An engine control apparatus of the present invention sets a target torque ?e, when the save mode m2 is set as an engine mode, according to the formula: ?e?TRQ2*RATIO1+TRQ3*(1?RATIO1) Basic target torque TRQ2 and TRQ3 are set based on the engine speed Ne and the throttle opening-degree ?acc and with reference to the normal mode map Mp1 and the power mode map Mp3 respectively. The correction factor RATIO1 is an addition rate which is set based on an accelerator opening-degree ?acc and a vehicle speed V and with reference to a correction factor map Mr1. The correction factor map Mr1 stores a correction factor RATIO1 near 0 (although 1?RATIO1>0) when the vehicle speed V is low and the accelerator opening-degree ?acc is high.

Abstract: When a combustion feedback correction coefficient to which a predetermined value is added in correspondence to half miss firing judgment exceeds a heavy fuel judgment value (K0), heavy fuel judgment is made, and heavy fuel corresponding control for increasing the fuel amount by a combustion feedback correction coefficient (Kfb) and by prolongation of increasing fuel amount (?) immediately after the startup is performed. When startup is consecutive startup, having a small drop width of a cooling water temperature (TH), from the last engine stop, and the number of times of ignition (Nig) accumulated during the last running is smaller than a warming judgment value (Nig0) at re-startup after running under the heavy fuel corresponding control, miss firing judgment is regarded as being impossible and alternative control for increasing the fuel amount is performed instead of the heavy fuel corresponding control.

Abstract: The control apparatus for the internal combustion engine increases a fuel injection amount under predetermined conditions, such as after the start of the internal combustion engine, at cold time, at acceleration requiring time, at gear shifting time from a neutral to a D-range, for example. When the fuel injection amount is increased during execution of air/fuel ratio feedback control, the feedback control follows the increase amount, and executes correction corresponding to the increase amount. Then, at the point of time when the correction corresponding to the increase amount is completed, the increase of the fuel injection amount is stopped quickly. Thereby, the increase of the fuel injection amount is not continued unnecessarily, and therefore useless consumption of the fuel can be suppressed. Also, it becomes possible to start other controls early by finishing increase quickly.

Abstract: A method for controlling fueling of an engine, the method comprising during an engine cold start and before the engine is warmed to a predetermined level, transitioning from open-loop fueling to closed-loop fueling, where during closed-loop fueling feedback from an exhaust gas oxygen sensor is utilized and where said closed-loop fueling generates a cycling of delivered fuel in maintaining exhaust air-fuel ratio at a desired level; and providing a fueling adjustment to a subsequent engine start in response to fueling information, said fueling information obtained over at least a complete cycle of closed-loop fueling following said transition from open-loop fueling.

Abstract: A method for starting an internal combustion engine of a hybrid-electric vehicle having a controller, the engine having a plurality of cylinders, each with at least an intake and exhaust valve, each of which may be held in a position for a cycle of a cylinder, the method comprising of deactivating a plurality of cylinders in said engine in response to a signal from the controller of the hybrid-electric vehicle by mechanically deactivating valves in each cylinder of the engine, the deactivation in response to a request from the controller of the hybrid-electric vehicle and to reduce a number of operating valves in each cylinder of the engine.

Abstract: An engine ECU executes a program including the steps of: starting an engine by transiently increasing an amount of fuel injection when a start request is detected; prohibiting calculation of a learn value when a condition for stopping transient increase is not satisfied; stopping transient increase when the condition for stopping transient increase is satisfied; steadily increasing the amount of fuel injection in accordance with a coolant temperature TW; and permitting calculation of a learn value during steady increase in accordance with the coolant temperature TW.

Abstract: At the time of start-up, fuel supply is made excessive. When air-fuel ratio feedback control is started while the fuel is excessive, the control is put into a state of overshoot or hunting, and it takes a long time to converge to the target air-fuel ratio. In an air-fuel ratio control apparatus, a selection switch is provided at the output of an integration calculation circuit to perform air-fuel ratio feedback control, and immediately after start-up of the engine, an upper/lower limit clip value for use immediately after start-up, which is smaller than a normal one, is selected to perform the air-fuel ratio feedback control. Even if the air-fuel ratio feedback control is started immediately after the start-up in a state where the fuel is excessive, the actual air-fuel ratio does not overshoot with respect to the target air-fuel ratio and is quickly converged to the target air-fuel ratio.

Abstract: In an internal combustion engine where an in-cylinder injector and an intake manifold injector can both be used, initial setting of a fuel injection ratio (DI ratio) in accordance with a condition of the engine is basically carried out in response to power-up of an engine ECU. Further, it is sensed that an engine start request is made after a prescribed period has elapsed since the power-up. In such a case, an initial setting value of the fuel injection ratio is updated in accordance with the condition of the engine at that time point. Thus, the fuel injection ratio between both injectors can appropriately be set in starting the engine, so that the engine is smoothly started.

Abstract: An engine (10) and a method of operating it during cold start and ensuing running using a cold start aid such as a glow plug control (24) and glow plugs (22). The control (24) monitors all glow plugs to distinguish between one that is effective and one that is ineffective. When a glow plug is disclosed to be ineffective, the engine control system (14) reduces the quantity of fuel introduced into the respective combustion chamber (12) in comparison to the quantity of fuel that would be introduced were the respective glow plug effective. This is beneficial in keeping the collection of hydrocarbons of surfaces of a diesel particulate filter (20) from increasing due to an ineffective glow plug.

Abstract: There is provided a method of controlling an internal combustion engine system. The method comprises supplying a first amount of electric energy to heat to an upstream sensor located in an exhaust gas passage from the internal combustion engine and upstream of an exhaust gas after-treatment device and adjusting an air-fuel mixture supplied to the internal combustion engine based on an output of the upstream sensor during a first engine operating condition, and supplying a second amount of electric energy, which is smaller than the first amount, to heat the upstream sensor and adjusting the air-fuel mixture based on an output of a downstream sensor located in the exhaust gas passage and downstream of the exhaust gas after-treatment device during a second engine operating condition.

Abstract: The invention improves a combustion at a starting time by refining a fuel at a time of starting the engine so as to minimize an amount of the fuel attached to a wall surface and appropriately form an air-fuel mixture. When the engine starts, a control apparatus executes a control of increasing a fuel pressure supplied to a fuel injector in comparison with a normal operating time just after the engine start, and a divisional injection control of divisionally injecting the fuel injection for one cycle of the engine by the fuel injector at a plurality of times.

Abstract: A system is described using a fuel quality sensor for controlling various aspects of engine operation. In particular, an acoustic wave sensor is utilized to measure viscosity and density of gasoline fuels. This measurement is utilized to predict engine combustion quality during an engine start. Based on the prediction, the method adjusts engine operating parameters (such as fuel injection amount and ignition timing) to achieve improved vehicle driveability and engine combustion.

Abstract: An air fuel ratio control system includes an exhaust gas sensor to sense an oxygen concentration in an exhaust passage of an internal combustion engine, and a controller. The controller is configured to judge that the exhaust gas sensor is in an active state, by monitoring a decrease of an output of the exhaust gas sensor from a level greater than a first predetermined value, to a level smaller than or equal to the predetermined first predetermined value, and to allow the air fuel ratio control when the exhaust gas sensor is judged to be in the active state.

Abstract: A system and method to control fuel delivery to an engine at startup includes a crank sensor that determines a rotational position of the engine. A control module calculates an air mass of a first cylinder based on the rotational position of the engine and delivers fuel to the first cylinder based on the air mass. The air mass is based on a volume, a pressure and a temperature of the first cylinder.

Abstract: A system is described using a fuel quality sensor or an estimate of fuel volatility for controlling various aspects of engine operation. For example, improved fuel tank leak detection may be achieved using an estimate of fuel volatility obtained from fuel purging operation.

Abstract: The present invention provides a method for computer controlled fuel injection into a vehicle engine under conditions where the vehicle is starting from cold or being restarted after a short period of being shut off. The method utilizes the value of conductance measured at an air/fuel sensor heater and t least one other engine parameter to determine the correct amount of fuel to be injected into the engine to accomplish efficient combustion. The computer controller adjusts the amount of fuel to be delivered from the fuel injector into the engine based on the value of conductance.

Abstract: A fuel properties estimating apparatus for an internal combustion engine includes a controller. The controller is configured to determine an estimated component concentration of a component, such as alcohol, in a fuel for the engine in accordance with an actual air fuel ratio of the engine, and to perform a plurality of estimating operations to determine the estimated component concentration at predetermined timings after an engine start of the engine.

Abstract: If it is determined that the present engine startup is a high-temperature startup, immediately fuel injection in concert with start of cranking is prohibited. After a delay time elapses following the start of cranking, or when THC<THCh is satisfied, fuel injection is started. Therefore, the cranking during the delay time cools interior of the combustion chambers. Since fuel injection starts after the cooling, pre-ignition can be prevented.

Abstract: An in-cylinder fuel injection internal combustion engine (1) is started up by means of compression stroke fuel injection from the beginning of cranking of the engine (1) to the end of a stratified combustion start-up period TST. If the engine (1) reaches complete combustion during the period, a warm-up operation is begun immediately. If the engine (1) does not reach complete combustion during the period, start-up of the engine (1) is continued using intake stroke fuel injection. By means of this control, stable start-up is assured while suppressing the discharge of unburned fuel during start-up of the engine (1).

Abstract: When an internal combustion engine is in a low load and low rotation operation, and also an elapsed time after the starting of engine operation is less than a predetermined period of time, a heater heating an air-fuel ratio sensor is turned OFF, to stop an air-fuel ratio feedback control. When the internal combustion engine is in the low load and low rotation operation after the predetermined period of time has elapsed, a low voltage is applied to the heater and also a gain is lowered, to perform the air-fuel ratio feedback control.

Abstract: An electronic control unit of an internal combustion engine performs preheat energization control before activation energization control. In the activation energization control, a gas sensor is energized with electric power capable of heating the gas sensor to activation temperature. In the preheat energization control, the gas sensor is energized with low electric power, which is not enough to heat the gas sensor to the activation temperature. Thus, while there is a possibility that water adheres to a sensor main body of the gas sensor, the sensor main body is prevented from being heated to high temperature. Meanwhile, even if water droplets exist in the sensor main body of the gas sensor, the water is vaporized gradually, while preventing the bumping of the water.

Abstract: A failure diagnosis device for an O2 sensor includes an O2 sensor; a heater driving unit driving a heater heating the O2 sensor; and a diagnosis unit controlling the heater driving unit heating the heater, and diagnosing O2 sensor failure after a given amount of time based on an O2 sensor activation status determination using O2 sensor outputs. The diagnosis unit includes a heater controlling unit controlling the heater driving unit; a time measuring unit measuring time that electric current is supplied to the heater, and time used in determining sensor abnormality; an activation status determining unit determining air/fuel ratio changes from a lean to rich state, or from a rich to lean state based on the O2 sensor output; and a failure determining unit determining sensor abnormality based on outputs from the time measuring unit and the activation status determining unit, thereby diagnosing O2 sensor failure without engine operation.

Abstract: A fuel properties estimating apparatus for an internal combustion engine includes a controller. The controller is configured to determine an estimated component concentration of a component, such as alcohol, in a fuel for the engine in accordance with an actual air fuel ratio of the engine, and to perform a plurality of estimating operations to determine the estimated component concentration at predetermined timings after an engine start of the engine.

Abstract: A control method adjusts fuel injection into an engine having a variable compression ratio. The method determines the cylinder air amount based on various sensors and the current compression ratio. The disclosed fuel injection method can perform both open loop and closed loop control. A method is also disclosed for putting the compression ratio to a base value during engine shutdown so that subsequent engine starts occur with a consistent compression ratio.

Abstract: A control method adjusts fuel injection into an engine having a variable compression ratio. The method determines the cylinder air amount based on various sensors and the current compression ratio. The disclosed fuel injection method can perform both open loop and closed loop control. A method is also disclosed for putting the compression ratio to a base value during engine shutdown so that subsequent engine starts occur with a consistent compression ratio.