Abstract: The disclosure relates to a self-adaptive oil spraying control system and method for a biodiesel engine. The control system includes an exhaust pipe, a gas sensor, a control module and an oil sprayer, wherein the exhaust pipe is connected to the oil sprayer, the gas sensor is mounted in the exhaust pipe, and the gas sensor and the oil sprayer are connected to the control module respectively. According to the control method, a main spray advance angle of the engine is subjected to closed-loop control directly through comparison between an idling steady state NOx emission signal and an idling steady state NOx emission value of pure diesel when the engine uses the biodiesel, so that emission of NOx in the exhaust is reduced. Compared with the prior art, the disclosure has the advantages of no need of detecting a biodiesel ratio, high efficiency, good effect and the like.

Abstract: A method for determining NOx sensor data falsification based on remote emission monitoring, includes the steps of: acquiring a plurality of vehicle data sets and urea level data of to-be-tested reference vehicles, wherein vehicle data include NOx sensor readings and corresponding engine data vectors; acquiring urea level data of reference vehicles; calculating standard urea consumption per kilometer; (2) acquiring an average distribution probability of the vehicle data of the to-be-tested vehicles through a probability distribution evaluation step; counting a total proportion of invalid or negative NOx sensor readings in the plurality of vehicle data sets; determining whether the data of the to-be-tested vehicles satisfy one or more falsification conditions; if so, determining that the data from the NOx sensors of the to-be-tested vehicles are falsified; otherwise, determining that the data from the NOx sensors of the to-be-tested vehicles are not falsified.

Abstract: The disclosure relates to a self-adaptive oil spraying control system and method for a biodiesel engine. The control system includes an exhaust pipe, a gas sensor, a control module and an oil sprayer, wherein the exhaust pipe is connected to the oil sprayer, the gas sensor is mounted in the exhaust pipe, and the gas sensor and the oil sprayer are connected to the control module respectively. According to the control method, a main spray advance angle of the engine is subjected to closed-loop control directly through comparison between an idling steady state NOx emission signal and an idling steady state NOx emission value of pure diesel when the engine uses the biodiesel, so that emission of NOx in the exhaust is reduced. Compared with the prior art, the disclosure has the advantages of no need of detecting a biodiesel ratio, high efficiency, good effect and the like.

Abstract: An air-fuel ratio control system for a hybrid vehicle engine is provided, including a torque coordination calculation module, which converts a target effective torque of a hybrid power control unit into a target indicated torque; a torque estimation module, which obtains an estimated indicated torque according to an operating state of an engine; an air-fuel ratio feedback control module, which generates a feedback correction factor based on deviation between the estimated indicated torque and the target indicated torque; and an air-fuel ratio feedforward control module, which converts the target indicated torque into an air-fuel ratio feedforward control signal according to a calibration parameter and engine speed. A target air-fuel ratio is obtained by correcting the air-fuel ratio feedforward control signal, via the feedback correction factor; and the target air-fuel ratio is configured to act on the engine to achieve air-fuel ratio control.

Abstract: A method for diagnosing a diesel oxidation catalyst fault includes: obtaining an standard molar enthalpy of formation-revolution speed-load table; obtaining a revolution speed, a load, a temperature difference of front and rear exhaust pipes, and a casing temperature, obtaining an standard molar enthalpy of formation corresponding to the revolution speed and the load from the standard molar enthalpy of formation-revolution speed-load table, and calculating an actual formation enthalpy corresponding to the temperature difference of front and rear exhaust pipes and the casing temperature from the temperature difference of front and rear exhaust pipes and the casing temperature; calculating a standard reaction enthalpy from the standard molar enthalpy of formation and standard conversion efficiency; and diagnosing a diesel oxidation catalyst fault by comparing the actual formation enthalpy with the standard reaction enthalpy.

Abstract: A method for controlling an exhaust after-treatment system based on NO2 medium adjustment includes the following steps: creating a diesel oxidation catalyst (DOC) reaction map, a diesel particulate filter (DPF) reaction map, and a selective catalytic reduction (SCR) reaction map; obtaining an SCR reaction temperature, desired SCR reaction efficiency, and obtaining NO2 demand according to the SCR reaction map; obtaining a DPF reaction temperature and differential pressure, and obtaining NO2 consumption from the DPF reaction map; obtaining NO2 production, and calculating NO2 input for SCR; if the NO2 input is not equal to the NO2 demand, calculating target NO2 production, obtaining a target DOC reaction temperature corresponding to the target NO2 production from the DOC reaction map, and adjusting a fuel injection rate so that the DOC reaction temperature is equal to the target DOC reaction temperature.

Abstract: An air-fuel ratio control system for a hybrid vehicle engine is provided, including a torque coordination calculation module, which converts a target effective torque of a hybrid power control unit into a target indicated torque; a torque estimation module, which obtains an estimated indicated torque according to an operating state of an engine; an air-fuel ratio feedback control module, which generates a feedback correction factor based on deviation between the estimated indicated torque and the target indicated torque; and an air-fuel ratio feedforward control module, which converts the target indicated torque into an air-fuel ratio feedforward control signal according to a calibration parameter and engine speed. A target air-fuel ratio is obtained by correcting the air-fuel ratio feedforward control signal, via the feedback correction factor; and the target air-fuel ratio is configured to act on the engine to achieve air-fuel ratio control.