Hybrid Excavator Controller Optimizing Battery Charge Timing
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Solution Overview
Problem
Hybrid hydraulic excavators face inefficiencies in fuel consumption during battery charging, as existing methods do not optimize charge timing with respect to fuel consumption, leading to decreased battery state of charge and potential operational failures under heavy loads.
Innovation Solution
Implementing a controller that estimates engine power requirements and restricts electricity generation by the motor generator to a low power zone with minimal energy loss, preventing high power zone electricity generation to reduce fuel consumption during battery charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor generator generates electricity during engine operation to charge the secondary battery, then the battery SOC is maintained, but the fuel consumption increases due to energy loss in high power zones
Solution Approach 1:
The control device changes the operating parameters of the motor generator by restricting electricity generation to low power zones where energy loss is minimal. The system monitors engine power output and only permits motor generator operation when engine power is within a predetermined range, thereby optimizing the balance between battery charging and fuel consumption.
2Quantity of substance
If the motor generator generates electricity during heavy load operation, then the battery can be charged, but the engine power requirement increases leading to higher energy loss
Solution Approach 1:
The control device performs preliminary assessment of engine power output before permitting motor generator operation. By checking whether engine power is within the predetermined low power zone range, the system proactively prevents electricity generation that would result in high energy loss, thereby optimizing the overall energy efficiency of the hybrid system.
3Productivity
If electricity generation is permitted without restrictions, then the battery charges faster, but the fuel consumption increases significantly
Solution Approach 1:
The control device dynamically adjusts the electricity generation behavior of the motor generator based on real-time engine power conditions. The system permits electricity generation only when engine power falls within the predetermined low power zone, creating a dynamic control strategy that adapts to varying operating conditions to optimize both charging efficiency and fuel 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
This approach enhances fuel efficiency by limiting electricity generation to low power zones, reducing energy loss and maintaining battery charge levels, thereby improving the hybrid excavator's operational capability under heavy loads.
Implementation Method 1
a motor generator (10) for generating electricity by using power of the engine (7)
Data Source
AI summary
A hybrid work machine includes: an engine controller (14) that controls rotational speed of an engine (7) in accordance with a target rotational speed input from an EC dial (31); an assist motor (10) that generates electricity using power of the engine (7); a hydraulic pump (6) operated using power of the engine and/or of the assist motor; and a vehicle body controller (11) that estimates power (Pe) the engine is required to output when a request to generate electricity is sent to the assist motor and permits the assist motor to generate electricity only when the engine power requirement is not greater than an electricity generation threshold value (Eth1). The electricity generation threshold value (Eth1) is determined based on the power and characteristics of energy loss of the engine (7).