The control system is carried out without changing the hydraulic system and the internal structure of the engine, which makes the output power of the engine match the actual load.
In the process of single bucket hydraulic excavator, the pressure of hydraulic system with different load is different. According to the pressure of hydraulic system, the load of single bucket hydraulic excavator is judged and the pressure is taken as the input quantity of single chip microcomputer. The single chip microcomputer adjusts the opening of engine throttle according to the pressure of single bucket hydraulic excavator, that is, to control the speed of engine, so that the engine and hydraulic system are always in the best economic working state. It has the following functions.
1.Automatic idle function
When the excavator is in non-working state, the computer automatically reduces the throttle opening and makes the engine in idle state, and its judgment is based on the pressure of the hydraulic system.
2.Dynamic Mode Control
The control system has three gears: high, medium and low. When the driver selects a gear by keystroke according to the need of work, the computer can control the engine to stabilize it at the corresponding speed. Because the absorption torque of the full power variable pump does not change with the speed in the constant power regulation section. Among them, the middle gear is the economic power mode file, when using this gear, the engine-hydraulic pump system is in the economic matching working state.
3.Short term overload function
The maximum pressure oil set by the excavator hydraulic system has a certain margin. When the system is overloaded in a short period of time, it generally does not have too much effect on the system, but it is overloaded for a long time. Will affect the life of the system and other components and other adverse consequences. Therefore, the control system has the function of short time overload. In order to protect the safety of the system, when the overload time is too long or the pressure is too large, the control system automatically reduces the engine speed to the minimum speed set by the system and alarm, so that the driver can change the operation mode. When the system pressure drops below the maximum design pressure, the control system quickly returns the engine to its original speed.
4.Overflow control
When the pressure of the hydraulic system approaches or reaches the opening pressure of the relief valve, the control system automatically and quickly reduces the engine speed to reduce the overflow. When the engine speed is reduced to the minimum speed set by the system and there is overload overflow, the overload alarm will be issued. When the pressure of the hydraulic system is less than the set maximum pressure, the control system will quickly restore the engine to its original speed.