Method for starting vehicle engine through combination of high pressure and low pressure

Abstract

The invention provides a method for starting a vehicle engine through combination of high pressure and low pressure. The method includes the steps that n1 is set to be the high-pressure entering rotating speed, and n2 is the engine ignition rotating speed; and when starting begins, a low pressure starting system singly works, and when the vehicle engine is dragged to rise the rotating speed to the n1, a high pressure starting system starts to work, and is combined with the low pressure starting system to perform combined action, and the engine is dragged to rise the rotating speed to the n2. By means of the technical scheme, the total energy of the high pressure starting system and the low pressure starting system can be combined, according to a given starting strategy, the output time of a storage battery and a starting motor in the low pressure system and a super-capacitor and a fly wheel generator in the high pressure system in the starting process are reasonably distributed, the cold starting process of the engine is completed, and the problems in vehicle low temperature cold starting are solved. The power of components can be saved, the system cost can be reduced, the reliability is high, the starting success rate is high, and the breakdown occurrence rate of the components is reduced.

Description

technical field [0001] The invention relates to a method for starting a vehicle engine, in particular to a method for starting a vehicle engine with high and low pressure. Background technique [0002] In traditional vehicles, a low-voltage power supply system is generally used, and the starting system is composed of a low-voltage battery, a starter motor and a transmission mechanism. When the engine is started, it is powered by a low-voltage battery. The starter meshes with the engine flywheel ring gear through the transmission mechanism, and transmits the starter torque to the engine. After starting, the starter is automatically separated from the ring gear to complete the starting process. [0003] With the development of various new technologies in the vehicle field, more and more high-voltage power supply systems are used in foreign and domestic aviation fields and land equipment. Most of the power supply system adopts a hybrid power supply with low-voltage 28V and high...

AI Technical Summary

Problems solved by technology

When low-voltage starting is used, it often occurs that when the speed of the starter motor reaches 90-100r / min, the starting failure is caused by insufficient discharge capacity of the battery, weak follow-up, and gearing.

When high-voltage starting is used, the flywheel generator outputs a locked-rotor torque, which requires continuous high-current discharge of the supercapacitor, but the capacity of the supercapacitor is not enough to support the starting process for several seconds or tens of seconds, and the voltage drops sharply to zero volts, making it impossible to start.

However, if the battery, starter motor, supercapacitor, flywheel generator and controller are selected according to the power torque in the low temperature environment, it will cause waste of power under most working conditions, increase the cost, and occupy the installation space of the vehicle, which is uneconomical

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