Hydrostatic Drive Engine Speed Control for Low-Speed Fuel Savings
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Solution Overview
Problem
Conventional work vehicles with hydrostatic drives often operate inefficiently when carrying heavy loads at low speeds, as they default to high engine idle settings, which consume more fuel than necessary.
Innovation Solution
A vehicle controller system that sets a fuel-efficient operation mode by adjusting engine speed to a nominal speed within the optimal fuel efficiency range of a brake-specific fuel consumption map and adjusting hydraulic pump displacement based on monitored engine speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine operates at high idle speed to ensure sufficient power for top ground speed requirements, then the vehicle can meet maximum speed requirements, but fuel consumption increases significantly
Solution Approach 1:
The system dynamically adjusts engine speed based on actual operational requirements rather than maintaining a fixed high idle speed. The controller continuously monitors ground speed, hydraulic pump displacement, and engine speed to determine optimal engine operating points, transitioning from static high idle to dynamic speed adjustment that matches actual power需求的
Solution Approach 2:
The system changes the engine operating parameters (speed and load) to operate within the optimal fuel efficiency range identified from brake specific fuel consumption map data. By adjusting engine speed and hydraulic pump displacement as variable parameters, the system optimizes fuel consumption while maintaining required performance
2Use of energy by moving object
If the engine speed is reduced to improve fuel economy, then fuel consumption decreases, but the engine may not provide sufficient power to meet ground speed requirements
Solution Approach 1:
The controller implements closed-loop feedback by continuously monitoring ground speed, hydraulic pump displacement, and engine speed, then adjusting engine speed commands based on deviations from desired performance. This feedback mechanism ensures that fuel efficiency optimizations do not compromise the engine's ability to meet ground speed requirements
Solution Approach 2:
The system integrates multiple control functions into a unified controller that simultaneously manages engine speed, hydraulic pump displacement, and ground speed coordination. This multi-functional approach allows the system to optimize fuel consumption while ensuring sufficient power delivery across varying operational conditions
3Use of energy by moving object
If the hydraulic pump displacement is increased to maintain ground speed at lower engine speeds, then fuel efficiency improves, but the system complexity increases
Solution Approach 1:
The system combines engine speed control and hydraulic pump displacement control into a single integrated control strategy. By merging these control functions and coordinating them workingly, the system achieves fuel efficiency improvements without proportionally increasing overall system complexity
Solution Approach 2:
The controller acts as an intermediary that coordinates between engine speed commands and hydraulic pump displacement adjustments. This intermediary control layer balances the interaction between engine and hydraulic system, optimizing fuel consumption while managing system complexity through centralized coordination
Data Source
AI summary
A system includes a vehicle controller which includes a memory configured to store instructions and one or more processors. The vehicle controller is configured to set a fuel efficient operation mode. The fuel efficient operation mode includes setting a commanded engine speed to a nominal engine speed located within a range of optimal fuel efficiency engine speeds of a brake specific fuel consumption map. The fuel efficient operation mode also includes instructing an engine to operate at the commanded engine speed. The fuel efficient operation mode also includes determining a monitored engine speed. The fuel efficient operation mode also includes adjusting a commanded pump displacement in response to the monitored engine speed exceeding the range of optimal fuel efficiency engine speeds. The fuel efficient operation mode also includes instructing a hydraulic pump to operate at the commanded pump displacement.