Electro-Hydraulic Pump DPF Regeneration for Construction Machines
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Solution Overview
Problem
Construction machines with electro-hydraulic pumps face challenges in performing active regeneration of diesel particulate filters (DPFs) due to the need for a non-work load to raise exhaust gas temperature, which is time-consuming and inefficient, especially in hermetic systems where torque generation is minimal.
Innovation Solution
A system and method that utilize electro-hydraulic pumps to create a non-work load by adjusting discharge flow rates and opening the center bypass line, allowing the diesel engine to overheat and generate high-temperature exhaust gas for exothermic reactions with a diesel oxidation catalyst (DOC) to combust trapped particulates, while minimizing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine is driven in an idle state without substantial work for active regeneration, then the construction machine can be stopped and the DPF can be regenerated, but a considerably long period of time is required to raise the exhaust gas temperature to the predetermined temperature needed for the exothermic reaction of the DOC
Solution Approach 1:
The system performs preliminary action by opening the center bypass cut valve before initiating active regeneration, allowing the electro-hydraulic pump to discharge working fluid through the center bypass line and create a non-work load condition. This preliminary setup enables the engine to quickly generate high-temperature exhaust gas without waiting for natural idle heating, thereby reducing the time required to reach the predetermined temperature for DOC exothermic reaction.
2Speed
If a non-work load is created by forcing the pump to discharge working fluid to apply a load to the engine without performing work, then the exhaust gas temperature can be raised quickly for active regeneration, but the hydraulic system requires additional control mechanisms and operations
Solution Approach 1:
The center bypass line and center bypass cut valve serve multiple functions: they enable the electro-hydraulic pump to create a non-work load for quick exhaust gas heating during active regeneration, while also maintaining the hermetic hydraulic system during normal operation. This multi-functionality allows the same hydraulic components to support both rapid temperature rise for regeneration and standard hydraulic system operation, avoiding the need for separate dedicated heating mechanisms.
3Use of energy by moving object
If the construction machine uses a hermetic hydraulic system with electro-hydraulic pumps, then fuel efficiency and work efficiency are improved, but torque generation in idle state is theoretically close to zero, making it difficult to create a non-work load for active regeneration
Solution Approach 1:
The system dynamically switches the hydraulic circuit configuration by controlling the center bypass cut valve to open or close the center bypass line. During active regeneration, the valve opens to allow the electro-hydraulic pump to discharge working fluid through the bypass, creating a non-work load that enables torque generation and quick exhaust gas heating. During normal operation, the valve closes to maintain the hermetic system for fuel efficiency. This dynamic switching allows the system to adapt between different operational modes.
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 enables quick and efficient active regeneration of DPFs, reducing the time required to reach regeneration temperature and minimizing fuel consumption, while preventing engine damage through safety cut-off valve control.
Implementation Method 1
a small amount of fuel, which is supplied to an exhaust path, causes an exothermic reaction with a diesel oxidation catalyst (DOC), which is also disposed on the exhaust path in advance, based on the temperature of the exhaust gas so as to raise the temperature of the exhaust gas to a higher temperature that is required to combust (regenerate) particulates
Implementation Method 2
a discharge flow rate of the electro-hydraulic pumps 10a and 10b may be adjusted by receiving an electronic control signal (for example, current signal) that is transmitted from a controller 50, for example, through adjustors 12a and 12b such as an electromagnetic proportional control valve (EPPR)
Implementation Method 3
combusting particulates trapped in the filter
Data Source
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AI summary
An exemplary embodiment of the present invention relates to a system for active regeneration of a DPF of a diesel engine, and more particularly, to a system and a method for active regeneration of a DPF including an electro-hydraulic pump, in which a non-work load is arbitrarily provided to the diesel engine to quickly perform active regeneration of the DPF even in a state in which substantial work of the construction machine having an electro-hydraulic pump is stopped, and to this end, provides a system and a method for active regeneration of a DPF of a construction machine in that, when performing the active regeneration of the DPF, a center bypass cut valve is driven to convert a hydraulic system of the construction machine to an open state, a predetermined flow rate of working fluid is discharged from the electro-hydraulic pump using an adjustor such as an electromagnetic proportional control valve (EPPR), and the working fluid is collected in to a tank through an opened center bypass line, thus allowing the working fluid to flow without driving a working machine to produce a so-called non-work load, and the engine is overheated by the load, and the temperature of the exhaust gas is raised to a predetermined temperature so as to satisfy a temperature condition required for the active regeneration of the DPF.