A PM detection system has a PM sensor, current detector, and control circuit. The circuit switches of a detection mode and a burning mode. In the detection mode, the control circuit prohibits supply of power to a heater and supplies a voltage between electrodes, and instructs the current detector to detect a current flowing between the electrodes. In the burning mode, the control circuit instructs the heater to generate heat energy to burn PM accumulated on an accumulation part. The control circuit judges PM has remained on the accumulation part when the detected current exceeds a threshold value, and performs the burning mode again. The system further has a pair of current detectors. Each current detector detects a leak current flowing from the heater to the electrodes through an insulation member when the heater generates heat energy. The circuit detects a sensor failure based on the detected leak current.

An oxygen sensor system includes an oxygen sensor and associated circuitry connected thereto. The oxygen sensor including a reference cell. The associated circuitry measures the impedance of the reference cell at time intervals, wherein the time intervals include a random component.

A control apparatus mounted on a diesel vehicle including an oxidation catalyst, a selective reduction catalyst, and a gas sensor includes an activation determination section, a concentration computation section, and a deterioration determination section. The concentration computation section computes the concentration of flammable gas from a sensor output in a period during which the activation determination section determines that the oxidation catalyst is not in the activated state and computes the concentration of ammonia gas from the sensor output in a period during which the activation determination section determines that the oxidation catalyst is in the activated state. The deterioration determination section determines whether or not the oxidation catalyst has deteriorated, on the basis of the concentration of the flammable gas computed by the concentration computation section.

Methods and systems are provided for a battery supplying power to an exhaust oxygen sensor heater. In one example, a method may include estimating a power delivered to the heater during heating of the sensor and in response to a power delivered from a battery being lower than a threshold, adjusting a battery charging strategy prior to an immediately subsequent engine start.

Systems, devices, methods and programs for reducing emissions from engines are provided. For example, one system for reducing emissions from engines comprises a heating controller coupled to an energy storage device (ESD). The heating controller is configured to control a heating element to heat one or more components of an after-treatment system using energy from the ESD under a first condition and to control the heating element to stop heating the one or more components of the after-treatment system when a second condition is satisfied. Additionally, another system for reducing emissions from engines comprises a controller detecting a decrease in a demanded torque from an engine and an ISG. The controller is then configured to operate a clutch to disengage the engine from the ISG, if after removing fuel from the engine, the sensed speed of the engine is above a threshold.

After an engine is started, an ECU performs first regeneration processing of a PM sensor through heating by a heater and, after the first regeneration processing, applies a voltage continuously to detection electrodes for a predetermined voltage application period. The ECU causes PM to adhere to an insulating substrate due to the voltage application and, at a time point after the predetermined time period has elapsed, determines the amount of PM that is adhering to the insulating substrate. When a predetermined condition is satisfied outside the voltage application period, the ECU determines whether the amount of adhering PM on the insulating substrate is equal to or greater than an excess determination threshold value. If the amount of adhering PM is determined to be equal to or greater than the excess determination threshold value, the ECU performs second regeneration processing of the PM sensor, through heating by the heater.

Methods and systems are provided for an oxygen sensor heater. In one example, a method may include applying a less than maximum duty cycle of voltage to the oxygen sensor heater during an engine cold start (e.g., when a temperature of the oxygen sensor is less than its light-off temperature) and adjusting the applied duty cycle of voltage to maintain a constant amount of power. In this way, the oxygen sensor may be heated at a constant rate even as a resistance of the oxygen sensor heater increases, decreasing an amount of time before the oxygen sensor reaches its light-off temperature.

An oxygen sensor system includes an oxygen sensor and associated circuitry connected thereto. The oxygen sensor including a reference cell. The associated circuitry measures the impedance of the reference cell at time intervals, wherein the time intervals include a random component.

The present disclosure relates to a device and a method for removing a carbon from an oxygen sensor. The device may include an oxygen sensor installed in a gas exhaust line of a vehicle to measure an oxygen content in an exhaust gas, a valve for transferring a high-pressure air flow to the oxygen sensor, a valve actuator for driving the valve, and a controller for controlling the valve actuator to open the valve when an abnormality occurs in the oxygen sensor. When the abnormality has occurred in the oxygen sensor, the valve for transferring the high-pressure air flow is opened, and a temperature of zirconia provided in the oxygen sensor is raised to remove a carbon deposited on the oxygen sensor.

An electronic control unit controls an air-fuel ratio sensor to detect an air-fuel ratio in an exhaust gas from an internal-combustion engine. An A/D converter and a sample value processor obtain a signal based on an impedance of the air-fuel ratio sensor in response to a power supply to the air-fuel ratio sensor via filters. A microcomputer determines an environment temperature of the air-fuel ratio sensor based on the signal. A switch or the microcomputer switches between an upstream side voltage supply path and a downstream side voltage supply path to obtain a signal depending on whether the air-fuel ratio sensor is operating in a low-temperature environment to improve the accuracy of the obtained signal.