Refuse Vehicle Hydraulic Pump Control for Torque Limiting
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Solution Overview
Problem
Existing refuse vehicles face issues with hydraulic systems that can lead to over-torqueing and stalling of the pump motor when increased power demand is required, potentially causing damage to the hydraulic components.
Innovation Solution
A torque limiting hydraulic circuit system that includes a spool valve to monitor hydraulic pressure and adjust the swashplate position of the variable displacement pump, diverting excess fluid to reduce torque and prevent stalling, using sensors and processors to manage fluid flow and actuator positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the variable displacement pump increases power output to meet increased demand, then the lifting system can handle heavier loads, but the pump motor may over-torque and stall
Solution Approach 1:
The control system continuously monitors hydraulic pressure and pump motor parameters, automatically adjusting pump displacement in real-time to maintain optimal operating conditions and prevent over-torqueing
Solution Approach 2:
The variable displacement pump dynamically adjusts its displacement based on real-time hydraulic pressure and load conditions, transitioning from fixed to variable output to match actual system needs without exceeding motor capacity
2Force
If the hydraulic system operates at high pressure to improve lifting capacity, then heavier waste receptacles can be handled, but the risk of component damage increases
Solution Approach 1:
The control system preemptively monitors pressure levels and automatically reduces pump output before dangerous pressure thresholds are reached, preventing component damage before it occurs
Solution Approach 2:
The control system acts as an intermediary between the pump and hydraulic components, regulating pressure flow to protect downstream components from pressure spikes and over-stress
3Productivity
If the pump motor operates continuously at high power demand, then lifting performance is improved, but energy consumption increases
Solution Approach 1:
The pump dynamically adjusts displacement based on actual load requirements, operating at high power only when needed and reducing output during lighter tasks to optimize energy consumption
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
Prevents over-torqueing and stalling of the hydraulic pump motor, maintaining system efficiency and preventing damage by dynamically adjusting fluid flow and actuator positions, ensuring continuous operation.
Implementation Method 1
A variable displacement pump is positioned within or adjacent the vehicle body and is configured to pump hydraulic fluid from a hydraulic fluid reservoir into a high pressure line of a hydraulic circuit
Implementation Method 2
A torque limiting valve is positioned downstream of the variable displacement pump and is configured to move between a first open position, a blocking position, and a second open position in response to hydraulic pressure within the high pressure line
Data Source
AI summary
A refuse vehicle includes a chassis and a vehicle body. A variable displacement pump is positioned within the vehicle body and is configured to pump hydraulic fluid from a hydraulic fluid reservoir into a high pressure line of a hydraulic circuit. A lifting system on the vehicle includes at least one actuator in fluid communication with the variable displacement pump, which delivers pressurized hydraulic fluid from the hydraulic fluid reservoir to the actuator through the high pressure line to adjust a position of the actuator. A valve is positioned downstream of the variable displacement pump. In a first valve position, the valve restricts flow outward from the high pressure line. In a second valve position, the valve directs fluid from the high pressure line into a lower pressure line to reduce a hydraulic pressure within the high pressure line and adjust an output parameter of the variable displacement pump.