A method to prevent obd torque limitation when the engine climbs hills

Abstract

The invention discloses a method for preventing an engine from OBD torque limitation in the slope climbing process. According to the method, a liquid level sensor is arranged at one side of a urea box; the variation amount of the liquid level in the urea box is collected; and if the variation amount is greater than a calibration value, it is considered that the engine is in the slope climbing process, and the engine is prohibited from OBD torque limitation. According to the method for preventing the engine from OBD torque limitation in the slope climbing process, on the basis that no extra hardware or sensor is added, it only needs to change the mounting position of the urea temperature liquid level sensor, and whether the engine is in the slope climbing process or not is recognized through control strategies. Whether the engine is in the upslope or downslope process is judged through liquid level inclination characteristics of various types of liquid such as urea liquid, fuel oil and engine oil appearing in the slope climbing or downslope process of the engine, and thus torque limitation of the engine is relieved.

Description

technical field [0001] The invention relates to a method for preventing OBD torque limitation when the engine climbs a slope. Background technique [0002] With the vigorous development of the automobile industry, engine exhaust emissions have become a factor that cannot be ignored in environmental pollution and human health. With the release of national engine emission regulations and on-board diagnostic system regulations, it is required that when the NOx in engine exhaust emissions exceeds 7g / Wk.h, the engine should be torque-limited. [0003] For safety reasons, regulations explicitly require engine torque to be limited in the following two situations: [0004] (1) When the engine is started next time; [0005] (2) When the vehicle speed is very low. [0006] Due to the variety of vehicles and the complexity of engine working conditions, the following situations may occur: in the same driving cycle, due to urea injection system failure or SCR crystallization, engine e...

AI Technical Summary

Problems solved by technology

[0005] (2) When the vehicle speed is very low

[0006] Due to the variety of vehicles and the complexity of engine working conditions, the following situations may occur: in the same driving cycle, due to urea injection system failure or SCR crystallization, engine exhaust emissions exceed the legal limit (7g / Wk.h ), but the vehicle is traveling at a fast speed, so the engine torque has not been limited. When the vehicle needs to climb a slope, the vehicle speed will be significantly reduced. If the engine torque is limited at this time, the consequences will be very serious

Images