Work Vehicle DPF Renewal Control Prioritization
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Solution Overview
Problem
In work vehicles equipped with both DPF and SCR systems, simultaneous execution of DPF renewal control and SCR reference output restricting control can lead to insufficient exhaust gas temperature for proper DPF renewal, potentially causing DPF system failure and requiring users to perform manual operations to suspend SCR control, disrupting their primary work.
Innovation Solution
A control unit prioritizes DPF renewal control over SCR reference operation restricting control, ensuring the DPF system is properly renewed by managing engine operating conditions to maintain suitable exhaust gas temperature, while also restricting engine operations to conserve reductants and prevent NOx emission when reductant levels are low or during SCR system abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SCR reference output restricting control is executed to conserve reductant or reduce NOx emission, then reductant storage is extended or NOx emission is reduced, but exhaust gas temperature decreases making DPF renewal impossible
Solution Approach 1:
The control system dynamically adjusts engine operating conditions based on the type of DPF renewal control being executed. When assisted-renewal control is detected, the system lifts SCR reference output restriction to enable higher exhaust gas temperatures, whereas for other renewal types the restriction remains active to conserve reductant.
Solution Approach 2:
The system changes the operating parameters of the SCR control by selectively applying or removing reference output restriction based on the DPF renewal control type. This parameter change allows the exhaust gas temperature to reach levels necessary for effective PM combustion during assisted-renewal control.
2Reliability
If DPF renewal control is executed to remove deposited PM, then PM collection performance is restored, but engine operating conditions must be changed affecting overall vehicle performance
Solution Approach 1:
The control system dynamically adjusts the balance between DPF renewal and engine output based on the specific renewal control type. For assisted-renewal control, the system prioritizes DPF renewal by lifting output restrictions, while for other renewal types, it maintains output restrictions to conserve reductant, creating a dynamic trade-off management strategy.
3Reliability
If post-injection DPF renewal control is executed to achieve high temperature, then PM removal efficiency is improved, but fuel consumption increases
Solution Approach 1:
The system applies post-injection only when absolutely necessary for assisted-renewal control, rather than using it routinely. This partial application of the high-energy-consuming method ensures PM removal efficiency is achieved only when the specific renewal control type requires it, minimizing unnecessary 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 configuration ensures the DPF system is properly maintained without user intervention, preventing failures and optimizing exhaust gas purification and reductant conservation, thus enhancing operational reliability and efficiency.
Implementation Method 1
a continuous regeneration type having an oxidation catalyst is adopted as the DPF system... The DPF renewal control restores the PM collection performance by, for example, changing an operating condition of the engine to increase the temperature of the exhaust gas so as to burn and remove the PM deposited in the soot filter by the exhaust gas from the engine
Implementation Method 2
an SCR (Selective Catalytic Reduction) system which adds a reductant such as urea water stored in a reductant storage tank to the exhaust gas from the engine to reduce nitrogen oxide (nitrogen oxide may be hereinafter abbreviated as 'NOx') contained in the exhaust gas
Data Source
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AI summary
It is an object of the present invention to avoid failure of a DPF system attributed to improperly executed DPF renewal control, and to properly operate the DPF system and an SCR system to favorably clean exhaust gas from an engine. The present invention includes a DPF system 11 configured to collect particulate matter contained in exhaust gas from an engine 10; an SCR system 12 configured to add, to the exhaust gas from the engine 10, a reductant stored in a reductant storage tank 12B to reduce nitrogen oxide contained in the exhaust gas; and a control unit 22 capable of executing a DPF renewal control whereby particulate matter collected and deposited in the DPF system 11 is burned and removed by using the exhaust gas from the engine 10 and an SCR reference operation restricting control to restrict an operating condition of the engine 10, the SCR reference operation restricting control executed when an amount of the reductant stored in the reductant storage tank 12B is a preset amount or less, or when an abnormality occurs in the SCR system 12, wherein the control unit 22 is configured to preferentially execute the DPF renewal control over the SCR reference operation restricting control.