Control method suitable for cold starting process of exhaust gas turbocharged engine

Abstract

The control method comprises the steps that in the cold starting process of the engine, an ECU reads cylinder pressure, vibration and crankshaft rotating speed signals, and the cold starting combustion condition of the engine is judged; if it is judged that the combustion efficiency is low or fire occurs, the ECU controls an exhaust valve to be opened early and closed late; after driving an exhaust gas turbocharger, the exhaust gas is all guided back into a cylinder for re-combustion; the fuel injection quantity of the next cycle is reduced; if it is judged that the combustion efficiency is medium, the ECU controls the exhaust valve to be closed earlier than opened earlier; part of waste gas is reserved in the cylinder to be combusted again, and the rest waste gas drives the waste gas turbocharger and then enters the postprocessor; the fuel injection quantity of the next cycle is reduced; if it is judged that combustion efficiency is high or combustion is normal, the ECU controls an exhaust valve to be opened and closed at night; all the waste gas is exhausted to drive the waste gas turbocharger and then enters the postprocessor; and normally spraying oil in the next cycle. According to the invention, the cold start ignition performance of the engine can be improved, the fuel economy is improved, and the emission of unburned HC and CO is reduced.

Description

Technical field [0001] The present invention relates to the field of the engine, more particularly, to a control method suitable for the cold starting process of the exhaust gas turbocharged engine. Background [0002] China's oil dependence on foreign countries has increased year by year, reaching 70.8% in 2019, while engine consumption accounts for more than 60%, so improving engine thermal efficiency and fuel economy is of great significance to China's energy security. At the same time, the upgrading of emission regulations also poses a huge challenge for efficient and clean combustion of engines. [0003] Studies have shown that harmful emissions from the cold start phase of the engine account for 60-80% of the total emissions, and there is a problem of insufficient power. This is due to the low wall temperature and cooling water temperature in the cylinder during the cold start of the engine, which is not conducive to the atomization and mixing of the fuel, making it diffic...

AI Technical Summary

Problems solved by technology

For the exhaust gas turbocharged engine, under cold start conditions, the engine speed is low, and due to insufficient combustion, the exhaust gas pressure and temperature are low, and the exhaust gas energy is insufficient to reduce the efficiency of the exhaust gas turbocharger, which cannot meet the power demand

At present, the cold start of the engine mostly adopts the way of intake air preheating, but an additional cold start auxiliary device is required

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