Catalyst ignition stage torque distribution method, system and device

Abstract

The invention provides a catalyst ignition stage torque distribution method. The method is used for a hybrid vehicle comprising a control system and an exhaust system. The method comprises the following steps that: a vehicle driving demand torque and the first temperature of a first catalytic converter are acquired, and whether the temperature of the first catalytic converter reaches an ignition temperature or not is judged; and if the temperature of the first catalytic converter does not reach the ignition temperature, the vehicle driving demand torque is compared with a motor torque output threshold value, and when the vehicle driving demand torque is smaller than or equal to the motor torque output threshold value, a motor control module is adopted to control the output torque of the motor to be the vehicle driving demand torque and control an engine to heat the first catalytic converter. On the basis of the method, the invention further provides a system and a device. According tothe method, system and device of the invention, different output torque distribution strategies are designed the engine works under proper working conditions, so that the temperature of the first catalytic converter and the temperature of a second catalytic converter are increased respectively, and meanwhile, the torque output range of the engine is limited; the situation that oil consumption andemission are not facilitated due to multiple transient working conditions of the engine, large load of a refrigerator and the like is avoided; and vehicle fuel economy is improved.

Description

technical field [0001] The invention relates to the field of hybrid vehicle control, in particular to a torque distribution method, system and device in the ignition-off stage of a catalytic converter. Background technique [0002] The three-way catalytic converter is the most important purification device for automobile exhaust emissions. Its conversion efficiency of harmful gases such as CO, HC and NOx produced by the operation of automobile engines is directly related to temperature. In general, the light-off temperature of the catalytic converter refers to the temperature at which the conversion efficiency of the catalytic converter to harmful gases reaches 50%. The conversion efficiency can reach more than 90%. Another study shows that the harmful gas emissions of the engine during its cold phase account for 50% to 80% of the total emissions of the entire emission test cycle. Therefore, shortening the light-off time of the catalytic converter and at the same time cont...

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Problems solved by technology

[0003] The main measures to shorten the ignition of the catalytic converter in traditional cars are: increasing the fuel injection volume and de-ignition angle, thereby increasing the exhaust temperature of the engine, but this method will lead to higher CO and HC emissions during the ignition of the catalytic converter; The auxiliary electric heating device of the catalytic converter requires special modification of the catalytic converter. The installation of a catalytic converter coating temperature sensor and a high-voltage electric heating device not only increases the difficulty of the design and processing of the catalytic converter, but also increases the design of the high-voltage wiring harness of the vehicle. It also increases the R&D and production costs and safety risks of the whole vehicle. In addition, there is a risk of battery power feeding; by optimizing the structural layout of the exhaust pipe, the three-way catalytic converter is closer to the engine exhaust. The air port uses higher temperature exhaust to heat the catalyst, but this method will accelerate the aging of the catalyst and affect the service life of the catalyst

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