Self-Propelled Work Machine Engine Speed Control
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Solution Overview
Problem
Auger-type snow removers experience frequent speed variations and operational inconvenience due to changing snow types and amounts, leading to inefficient snow removal and increased operator workload, especially during engine warm-up when the load on the engine is high.
Innovation Solution
A self-propelled work machine with electric motors for travel units and an engine-driven work unit, employing PID control to maintain a reference rotational speed of the engine, reducing the actual speed of electric motors when the engine becomes overloaded, and using an electronic governor to adjust choke and throttle valves for smoother operation during startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the travel speed is increased to improve snow removal efficiency, then the amount of snow removed increases, but the load on the engine increases causing rotational speed fluctuation
Solution Approach 1:
The control unit continuously monitors the actual rotational speed of the engine and compares it with the target rotational speed. When the actual speed deviates from the target (indicating overload), the control unit automatically reduces the travel speed of the travel units, thereby reducing the load on the engine and stabilizing the rotational speed. This closed-loop feedback mechanism resolves the contradiction by dynamically adjusting travel speed based on engine load conditions.
2Reliability
If the travel speed is frequently adjusted to match engine load changes, then the engine rotational speed can be maintained, but the operator workload increases and operation becomes inconvenient
Solution Approach 1:
The control system automatically monitors engine rotational speed and adjusts travel speed without operator intervention. The control unit detects when the engine is overloaded through rotational speed deviation and autonomously reduces travel speed, eliminating the need for the operator to manually adjust settings. This self-service approach maintains engine stability while significantly reducing operator workload.
3Temperature
If the engine warm-up is performed manually by closing the choke valve, then the engine can be warmed up, but the load on the engine increases and travel speed must be reduced
Solution Approach 1:
The electronic governor dynamically adjusts the choke valve position based on engine operating conditions during warm-up. Instead of maintaining a fixed closed position, the choke valve is gradually opened as the engine warms up, and the control unit simultaneously adjusts travel speed to prevent overload. This dynamic adjustment resolves the contradiction by allowing both warm-up and maintained travel speed through coordinated control of choke valve and travel motor.
Data Source
AI summary
A self-propelled work machine, in which the load of the work unit increases according to an increase in the travel speed. The self-propelled work machine includes electric motors for driving the travel units, an engine for driving the work unit, a work drive instruction unit for instructing the work unit to turn on, and a control unit for controlling the electric motors. The control unit reduces the actual speed of the electric motors by using PID control so that the actual rotational speed of the engine returns to a reference rotational speed when the actual rotational speed of the engine falls below the reference rotational speed in the state in which the work unit is turned on by the work drive instruction unit. The reference rotational speed is a reference value used when the work unit is driven by the engine.