Industrial Vehicle Engine Speed Control for Creep Stability
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Solution Overview
Problem
Industrial vehicles, such as forklift trucks, experience unwanted creeping due to power transmission mechanisms, which can lead to instability during loading operations, particularly when idling at high speeds to suppress engine vibration. Existing solutions do not effectively control creeping speed or stabilize engine operation during non-traveling states.
Innovation Solution
An industrial vehicle equipped with a control unit that adjusts engine speed based on vehicle speed detection, switching from a high idling speed to a lower creeping speed when the vehicle transitions to power transmission, using a power transmission mechanism with a torque converter and automatic transmission, to achieve a desired stabilized creeping speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the idling speed is set relatively high to suppress engine vibration and ensure stabilized operation, then engine vibration suppression and operational stability are improved, but the vehicle creeps at an unstable or excessive speed during loading operations
Solution Approach 1:
The patent applies dynamics by making the engine idle speed adjustable rather than fixed. The control unit dynamically changes the idle speed between a first idle speed (higher) for vibration suppression and a second idle speed (lower) for controlled creeping, allowing the system to adapt to different operational requirements and resolve the contradiction between stable engine operation and controlled vehicle speed
Solution Approach 2:
The patent changes the engine speed parameter based on operational state. By detecting whether the vehicle is in a traveling state or non-traveling state (loading operation), the control unit adjusts the idle speed parameter to appropriate values, thereby controlling both engine stability and vehicle creeping speed through parameter optimization
2Loss of time
If the engine speed is rapidly changed from high idling speed to lower speed during transition to power transmission, then response time is improved, but vehicle speed stability deteriorates due to rapid changes
Solution Approach 1:
The patent applies periodic action through gradual, staged adjustment of engine speed rather than immediate change. The control unit reduces idle speed in controlled increments over a predetermined period, preventing sudden vehicle speed changes while still achieving the transition from high idling to lower creeping speed, thus maintaining both response efficiency and vehicle stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively stabilizes the creeping speed of industrial vehicles, suppresses engine vibration during non-traveling states, and ensures smooth operation by gradually changing engine speed, thereby maintaining stability and controlling rapid changes in vehicle speed.
Implementation Method 1
a power transmission mechanism that transmits power of the engine to the drive wheel
Data Source
Figure 1
Figure 2~3B
AI summary
An industrial vehicle (10) has an engine (19), a drive wheel (30), and a power transmission mechanism (22) that transmits power of the engine (19) to the drive wheel (30). The industrial vehicle includes a control unit (31, 32) that controls an engine speed of the engine (19) and a vehicle speed detection unit (36) that detects a vehicle speed of the vehicle (10). The control unit (31, 32) controls the engine speed of the vehicle (10) at a first engine speed (R1) when the vehicle (10) is in a non-traveling state, and when the vehicle speed has exceeded a predetermined vehicle speed (X), the control unit (31, 32) controls the engine speed at a second engine speed (R2) that is lower than the first engine speed (R1), and the second engine speed (R2) is set to generate a desired creeping speed.