Forklift Engine Control Apparatus for Mode-Specific Output Restriction
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Solution Overview
Problem
Conventional traveling speed restriction apparatuses for engine-powered forklifts restrict engine output to a preset value, limiting actuator performance and increasing safety hazards due to restricted driving force during heavy cargo operations and high-speed travel.
Innovation Solution
A control apparatus with a mode detecting mechanism using a pressure switch to differentiate between traveling and working modes, allowing engine output to exceed preset values during working modes for smooth actuator operation while restricting it in traveling modes to prevent excessive speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output of the engine is restricted to a preset output value to limit traveling speed, then safety hazards are reduced, but the driving force of the actuator is restricted and smooth operation cannot be ensured
Solution Approach 1:
The patent applies dynamics by making the engine output restriction adjustable rather than fixed. The controller dynamically adjusts the predetermined output value based on operating conditions, allowing the restriction level to change according to whether the forklift is in traveling mode or working mode, thereby resolving the contradiction between safety and operational smoothness.
Solution Approach 2:
The patent changes the parameter of engine output restriction by allowing the controller to adjust the predetermined output value. When working mode is detected, the restriction is relaxed to allow higher output for smooth actuator operation; when traveling mode is detected, the restriction is maintained for safety. This parameter adjustment resolves the contradiction between safety and operational requirements.
2Power
If the accelerator pedal is pushed beyond the predetermined position to increase engine output for heavy cargo operations, then actuator driving force is improved, but the traveling speed increases excessively creating safety hazards
Solution Approach 1:
The patent uses feedback by detecting the position of the accelerator pedal and the operating mode of the forklift. The controller continuously monitors these parameters and adjusts the engine output restriction accordingly. When the accelerator pedal is pushed beyond the predetermined position during working mode, the system allows higher output without triggering speed restrictions, thereby providing adequate driving force without excessive traveling speed.
Solution Approach 2:
The system dynamically adjusts engine output restrictions based on real-time operating conditions. When heavy cargo operations are detected (accelerator pedal beyond predetermined position), the system dynamically increases the allowed engine output for actuator operation while maintaining speed restrictions for traveling, thus resolving the contradiction between power and speed.
3Speed
If a stopper is used to prevent rotation of the accelerator pedal beyond a predetermined position, then engine output is restricted to prevent high-speed travel, but the driving force of the actuator is also restricted
Solution Approach 1:
The patent replaces the mechanical stopper system with an electronic control system. Instead of physically preventing accelerator pedal rotation, the controller electronically manages engine output based on detected operating mode. This substitution allows the system to differentiate between traveling mode (speed restriction applied) and working mode (power restriction relaxed), thereby maintaining traveling speed control while ensuring adequate actuator driving force when needed.
Solution Approach 2:
The system changes the parameter of engine output restriction dynamically based on operating mode detection. Rather than maintaining a fixed restriction like the mechanical stopper, the controller adjusts the restriction level: applying speed restrictions during traveling mode while relaxing power restrictions during working mode. This parameter adjustment resolves the contradiction between speed control and power availability.
Data Source
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AI summary
Disclosed herein is a control apparatus for an engine-powered forklift. The control apparatus of the present invention includes a mode detecting means (30) for detecting whether the forklift is in a traveling mode or a working mode, and a controller (40), which controls the engine (1) of the forklift such that, when the forklift is in the traveling mode, the output of the engine (1) is restricted from increasing to a preset output value or more, and, when the forklift is in the working mode, the output of the engine (1) is allowed to increase to the preset output value or more.