Construction Machine Control Unit Auto Idle Speed Adjustment
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Solution Overview
Problem
Construction machines experience reduced engine output due to changes in environment such as altitude, coolant temperature, and fuel temperature, leading to potential engine stalling and poor operating feel during reset from auto idle state.
Innovation Solution
A control unit for construction machines that adjusts engine idle speed based on detected environmental conditions, including atmospheric pressure, coolant temperature, and fuel temperature, to maintain consistent engine output and prevent lug-down phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine speed is reduced to idle speed during auto idle control, then fuel efficiency is improved, but the engine may stall when load is suddenly applied in high altitude environments
Solution Approach 1:
The patent changes the idle speed parameter based on environmental conditions (atmospheric pressure, coolant temperature, fuel temperature). When atmospheric pressure is low (high altitude), the idle speed is set higher to compensate for reduced engine output. When atmospheric pressure is normal, the idle speed is set lower to maximize fuel efficiency. This dynamic parameter adjustment resolves the contradiction between fuel efficiency and engine stability.
2Object-generated harmful factors
If the engine speed is reduced during auto idle control, then noise is reduced, but the operating feel deteriorates when reset to normal operation in high altitude environments
Solution Approach 1:
The patent adjusts the idle speed parameter based on environmental conditions to maintain appropriate engine response during reset. In high altitude environments, the higher idle speed setting ensures the engine can respond adequately when load is applied, maintaining good operating feel. In normal environments, the lower idle speed provides noise reduction while still allowing adequate response.
3Device complexity
If a fixed idle speed is used during auto idle control, then the control system is simple, but it cannot adapt to environmental changes such as altitude and temperature
Solution Approach 1:
The patent implements a feedback control system that monitors environmental parameters (atmospheric pressure via altitude sensor, coolant temperature, fuel temperature) and adjusts the idle speed accordingly. The control unit receives feedback from these sensors and automatically modifies the idle speed setting to optimize both fuel efficiency and engine performance for the current environmental conditions.
Solution Approach 2:
The patent transforms the static idle speed parameter into a dynamic one that automatically adapts to changing environmental conditions. The idle speed is no longer fixed but varies based on real-time measurements of atmospheric pressure, coolant temperature, and fuel temperature, allowing the system to maintain optimal performance across different operating environments.
Data Source
AI summary
A target speed setting section sets a target speed of an engine to an idle speed that is lower than an input speed with an engine control dial when no operating signal is output from a control lever over a predetermined period of time. A speed control section controls the speed of the engine based on the target speed set by the target speed setting section, which includes an idle speed setting section that corrects the idle speed according to values detected by sensors so that reduction in an output of the engine due to a change in a state quantity associated with an environment under which the engine is placed can be inhibited. This allows a good operating condition to be achieved during a reset from an auto idle state even with an engine output has been reduced according to a change in environment.