An internal combustion engine fluidly coupled to an exhaust aftertreatment system that includes an exhaust purifying device is described. A pressure monitoring device is disposed to monitor a pressure differential between an inlet and an outlet of the exhaust purifying device. A method of monitoring the exhaust purifying device includes monitoring a pressure differential between an inlet and an outlet thereof, and determining an exhaust gas flowrate associated with operation of the internal combustion engine. A raw flow resistance is dynamically determined based upon the pressure differential and the exhaust gas flowrate, and an estimated flow resistance is determined based upon the raw flow resistance. The exhaust purifying device is evaluated based upon the estimated flow resistance.

A system to detect the presence of a catalyst includes an exhaust gas tube, a first temperature sensing device, a second temperature sensing device, a flow rate measurement device, and a processing device. The first temperature sensing device measures a first temperature of exhaust gas upstream of the exhaust gas tube. The second temperature sensing device measures a second temperature of the exhaust gas downstream of the exhaust gas tube. The processing device estimates an expected time delay between the measured inlet and outlet exhaust gas temperatures corresponding to a system with a catalyst present. The processing device may also determine the presence of a catalyst by comparing the measured second temperature to the measured first temperature and comparing the measured second temperature to an estimated delayed first temperature associated with the expected time delay.

An exhaust gas control apparatus removal determination device that performs an exhaust gas control apparatus removal determination processing based on a change in temperature of exhaust gas flowing into an exhaust gas control apparatus provided in an exhaust path of an engine and a change in temperature of exhaust gas flowing out. The controller determines whether the first state in which the difference between the measured value and the estimated value of the engine output is greater than or equal to a predetermined value continues for a predetermined time or longer, and determines that the engine output is in the first state. If it is determined, execution of the removal determination processing is prohibited.

A system to detect the presence of a catalyst includes an exhaust gas tube, a first temperature sensing device, a second temperature sensing device, a flow rate measurement device, and a processing device. The first temperature sensing device measures a first temperature of exhaust gas upstream of the exhaust gas tube. The second temperature sensing device measures a second temperature of the exhaust gas downstream of the exhaust gas tube. The processing device estimates an expected time delay between the measured inlet and outlet exhaust gas temperatures corresponding to a system with a catalyst present. The processing device may also determine the presence of a catalyst by comparing the measured second temperature to the measured first temperature and comparing the measured second temperature to an estimated delayed first temperature associated with the expected time delay.

In a method of operating an exhaust emission control device, the presence of an actual pressure loss of a particulate filter is determined, and a model pressure loss is determined as a function of a state variable. On the basis of the actual pressure loss and the model pressure loss a pressure quotient is determined and a condition of the particulate filter is ascertained in a diagnostic mode in response to the pressure quotient.

A radio frequency sensing, control, and particulate matter diagnostics network and system and method and, more specifically, a radio frequency particulate filter diagnostics system comprising a housing including an inlet connected to a source of particulate matter, a particulate filter in the housing and adapted for filtering the particulate matter, and a radio frequency sensor adapted to detect conditions of abnormal particulate filter or system operation and including at least one radio frequency probe configured to be in contact with the housing for the particulate filter housing and adapted to receive radio frequency signals and a radio frequency control unit in communication with the radio frequency probe.

A straddled vehicle, including: an engine, which includes a combustion chamber; a three-way catalyst, which is configured to purify exhaust gas exhausted from the combustion chamber; an upstream oxygen sensor, which is provided upstream of the three-way catalyst in a flow direction of the exhaust gas, and is configured to detect an oxygen concentration in the exhaust gas; a downstream oxygen sensor, which is provided downstream of the three-way catalyst in the flow direction of the exhaust gas, and is configured to detect the oxygen concentration in the exhaust gas; and a controller, which includes a processor, and a non-transitory storage medium containing program instructions, execution of which by the processor causes the controller to execute a detachment determination process of determining whether the three-way catalyst is detached at least based on a signal input as a signal of the downstream oxygen sensor.

A system to detect the presence of a catalyst includes an exhaust gas tube, a first temperature sensing device, a second temperature sensing device, a flow rate measurement device, and a processing device. The first temperature sensing device measures a first temperature of exhaust gas upstream of the exhaust gas tube. The second temperature sensing device measures a second temperature of the exhaust gas downstream of the exhaust gas tube. The processing device estimates an expected time delay between the measured inlet and outlet exhaust gas temperatures corresponding to a system with a catalyst present. The processing device may also determine the presence of a catalyst by comparing the measured second temperature to the measured first temperature and comparing the measured second temperature to an estimated delayed first temperature associated with the expected time delay.

A removal determination device that accurately determines a removal of an exhaust gas purification device from an exhaust pipe. The removal determination device comprises: an input temperature sensor detecting a temperature at an upstream side of casing; an output temperature sensor detecting a temperature at a downstream side of the casing; an engine stop time collector measuring a time period from an inactivation of an engine to a startup of the engine; and a determiner determining a presence of the exhaust gas purifying device based on the input temperature and the output temperature, in a case that the time period is equal to or longer than a predetermined time.

A method and a control unit for checking an exhaust gas system in a vehicle. A control unit in the vehicle receives data from sensors of the vehicle and sends out control commands to final control elements of the vehicle. The control unit is in communication connection with an external computer located outside of the vehicle. The external computer causes the control unit to make an active intervention in the exhaust gas system by actuating final control elements of the vehicle. The control unit receives sensor data from the exhaust gas system, which it forwards to the external computer. Based on the sensor data from the sensors, the external computer rates the exhaust gas system as OK or manipulated.