Work Vehicle Electro-Hydraulic System for Engine-Off Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Work vehicles like tractors lack a start and stop system for their internal combustion engines due to the dependency on hydraulic systems for auxiliary components, leading to pressure drops and operational issues when the engine is shut down, and restart times are prolonged.
Innovation Solution
An electro-hydraulic system with an accumulator and electric machine maintains hydraulic pressure using stored energy when the engine is off, and switches to engine operation when needed, ensuring continuous hydraulic actuator functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the internal combustion engine is temporarily shut down to save fuel, then fuel consumption is reduced, but hydraulic system pressure drops and auxiliary components cannot operate
Solution Approach 1:
The accumulator is pre-charged with hydraulic fluid under pressure before engine shutdown. This preliminary action ensures that when the engine stops, the accumulator immediately provides the necessary hydraulic pressure to maintain operation of auxiliary components without interruption.
Solution Approach 2:
The accumulator is extracted from the traditional hydraulic circuit as a separate energy storage component. It is connected via a control valve that can isolate it from the main hydraulic system, allowing it to function as an independent energy reservoir that supplements the hydraulic pump during engine shutdown periods.
2Object-generated harmful factors
If the internal combustion engine is shut down, then fuel is saved and emissions are reduced, but restart time increases due to hydraulic pressure buildup requirements
Solution Approach 1:
The accumulator maintains hydraulic pressure in the system during engine shutdown, so when the engine restarts, the hydraulic system is already pressurized and ready for immediate operation. This eliminates the delay that would otherwise be required to rebuild hydraulic pressure after engine shutdown.
3Reliability
If the internal combustion engine continuously runs to maintain hydraulic pressure, then hydraulic system reliability is ensured, but fuel consumption increases
Solution Approach 1:
Instead of continuous engine operation, the system uses periodic action where the engine runs only when needed to recharge the accumulator. The accumulator then provides hydraulic pressure during periods when the engine is off, creating an alternating pattern of engine operation and shutdown that reduces overall fuel consumption while maintaining system reliability.
Solution Approach 2:
The accumulator serves itself by automatically providing hydraulic pressure during engine shutdown without requiring continuous engine operation. The control valve automatically manages the interaction between the accumulator and hydraulic pump, allowing the system to self-regulate and maintain functionality without constant engine running.
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
Enables the operation of hydraulic systems without engine shutdown, saving fuel, reducing noise and emissions, and optimizing engine idle time.
Implementation Method 1
a hydraulic arrangement (10) comprising a hydraulic pump (14) driven by the internal combustion engine (9) and configured to provide pressurized hydraulic fluid towards a hydraulic circuit (16) of the work vehicle (1)
Implementation Method 2
an electro-hydraulic pumping means (24), which is configured to be hydraulically connected to the hydraulic circuit (16) and adapted to provide pressurized hydraulic fluid towards the hydraulic circuit (16}
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A work vehicle (1) comprising an internal combustion engine (9), a hydraulic actuator (11); and a hydraulic arrangement (10) configured to provide a pressurized hydraulic fluid to the hydraulic actuator (11); the hydraulic arrangement (10) comprising: an electro-hydraulic portion (20); a hydraulic circuit (16) adapted to fluidly connect the outlet of the electro-hydraulic portion (20) with the hydraulic actuator (11). The electro-hydraulic portion (20) comprising: an electric machine (22) carried by the internal combustion engine (9); accumulator means (26) electrically connected to the electric machine (22) and configured to store the electric energy provided by said first electric machine (22); and electro-hydraulic pumping means (24), which are electrically connected to the electric machine (22) and to the accumulator means (26) and are fluidly connected to the hydraulic circuit (16).