Exhaust Pipe Injector Pressure Stabilization
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Solution Overview
Problem
Existing exhaust-pipe injection systems face challenges in accurately controlling the exhaust injection amount due to pressure pulsations in the fuel line, which leads to instability in the injection process, especially when the engine revolution is low and the in-cylinder injection amount is high.
Innovation Solution
Incorporating a pressure compensating device, such as a buffer tank or accumulator, near the exhaust pipe injector and a fuel pressure sensor upstream from this device to monitor and stabilize the injection pressure, allowing for precise feedback control of the exhaust injection amount by adjusting the open time of the exhaust pipe injector based on the monitored pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fuel pressure sensor is provided in the fuel line near the exhaust pipe injector to monitor injection pressure, then the injection amount control accuracy is improved, but pressure pulsations from the injector's open/close operation cause measurement instability
Solution Approach 1:
A pressure compensating device is introduced as an intermediary component between the fuel pressure sensor and the exhaust pipe injector. This device filters out pressure pulsations generated by the injector's open/close operations, allowing the sensor to accurately monitor the average injection pressure without being affected by transient fluctuations. The compensating device acts as a buffer that mediates between the pulsating pressure source and the measurement instrument.
Solution Approach 2:
The pressure compensating device provides beforehand cushioning by absorbing and dampening pressure pulsations before they reach the fuel pressure sensor. This preemptive cushioning ensures that the sensor receives a stabilized pressure signal, preventing measurement instability caused by the injector's periodic operation.
2Quantity of substance
If the exhaust pipe injector operates at high duty ratios to maintain injection amount, then the desired injection volume is achieved, but pressure drops in the fuel line reduce injection accuracy
Solution Approach 1:
The system implements feedback control by continuously monitoring the actual injection pressure with the fuel pressure sensor and using this information to adjust the injector's open time. The injection control device calculates the required open time based on both the desired injection amount and the monitored pressure, ensuring accurate injection control even when pressure conditions vary. This closed-loop feedback mechanism compensates for pressure drops that occur at high duty ratios.
Solution Approach 2:
The injection control device dynamically adjusts the injector's open time based on real-time pressure conditions. Rather than using a fixed duty ratio, the system adapts the injection parameters according to the monitored pressure, allowing accurate control across varying operating conditions including high duty ratio scenarios where pressure drops occur.
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 effectively suppresses pressure fluctuations in the fuel line, enabling accurate monitoring and stabilization of the injection amount, thereby improving temperature stability for exhaust gas purifiers and maintaining a stable λ-value during desulfurization control.
Implementation Method 1
a pressure compensating device provided in the vicinity of the exhaust pipe injector of the fuel line; It is preferred that the pressure compensating device suppresses a fluctuation in the monitoring value of the fuel pressure sensor caused by an open/close operation of the exhaust pipe injector
Implementation Method 2
a fuel pressure sensor provided in the fuel line in an upstream side from the pressure compensating means
Implementation Method 3
an exhaust pipe injector that injects fuel to an exhaust pipe of an internal combustion engine
Implementation Method 4
exhaust pipe injection is a method of adding unburned fuel to the exhaust gas from the exhaust pipe injector provided in the exhaust pipe
Implementation Method 5
the unburned fuel is added to the exhaust gas, and the exhaust gas is heated by oxidizing and burning the fuel using an oxidation catalyst
Implementation Method 6
the exhaust gas is heated by oxidizing and burning the fuel using an oxidation catalyst, so that the purifier is regenerated using the exhaust gas having a high temperature
Data Source
AI summary
An exhaust-pipe injection system capable of accurately monitoring a lowered injection pressure generated in a fuel line due to exhaust pipe injection and appropriately perform feedback control for the exhaust injection amount. The exhaust-pipe injection system includes: an exhaust pipe injector that injects fuel to an exhaust pipe of an internal combustion engine; a supply pump that sends a fuel to the exhaust pipe injector via a fuel line; a pressure compensating device provided in the vicinity of the exhaust pipe injector of the fuel line; a fuel pressure sensor provided in the fuel line in an upstream side from the pressure compensating device; and an injection control device that adjusts an injection amount of the exhaust pipe injector based on a monitoring value of the fuel pressure sensor.