FIELD OF THE INVENTION
The present invention relates generally to exhaust emission reduction systems for diesel engine exhaust streams that have diesel particulate filters. More specifically, the present invention is an active control system that reduces particulate matter buildup in the diesel particulate filters while eliminating high engine exhaust back pressure.
BACKGROUND OF THE INVENTION
Diesel Particulate Filters (DPF's) used in the exhaust stream of a diesel engine are susceptible to plugging as a result of particulate matter coming from the engine exhaust under certain engine operating conditions. One, but not the only, example of such an operating condition is during the engine start up when the DPF has not reached a minimum operating temperature, known as the activation temperature, necessary for it to burn off a portion of the accumulated particulate matter. If the DPF is subject to an exhaust flow while it is below its activation temperature for too many operating hours, the channels in the DPF can become plugged decreasing the efficiency of the DPF. A plugged DPF may create engine exhaust back pressure, which exceeds the allowable specifications for the diesel engine, resulting engine stalling or possible damage to the engine. This disclosure provides a system to ensure that the DPF is less likely to become plugged from an exhaust gas flow. Additionally, the present invention also ensures that the engine exhaust back pressure does not exceed beyond the allowable specification of the diesel engine.
The present invention provides an active control system so that the exhaust gas flow for the diesel engine can be diverted into the present invention until the DPF reaches the activation temperature. The diverting process for the exhaust gas flow is carried out through a control unit as the pressure or temperature across the DPF is determined through a sensor and compared with a preset value of the control unit.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the present invention, showing the first configuration of the at least one pressure sensor.
FIG. 2 is a side view of the present invention, showing the first configuration of the at least one pressure sensor.
FIG. 3 is a side view of the present invention, showing the first configuration of the at least one pressure sensor and the off-position of the control valve.
FIG. 4 is a side view of the present invention, showing the first configuration of the at least one pressure sensor and the on-position of the control valve.
FIG. 5 is a side view of the present invention, showing the second configuration of the at least one pressure sensor and the off-position of the control valve.
FIG. 6 is a side view of the present invention, showing the second configuration of the at least one pressure sensor and the on-position of the control valve.
DETAIL DESCRIPTIONS OF THE INVENTION
All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention.
The present invention is an active control system for a diesel exhaust system so that the particulate filter of the diesel exhaust system is able to efficiently function with a minimum amount of particulate matter buildup. As a result of minimum particulate matter buildup, the present invention also eliminates unnecessary back pressure of the exhaust system that can damage the engine. The present invention comprises a particulate filter unit 1, at least one pressure sensor 6, a control unit 9, and a bypass unit 10. The general configuration of the present invention is shown In FIG. 1 and FIG. 2, where the at least one pressure sensor 6 is in fluid communication with the particulate filter unit 1 while the at least one pressure sensor 6 electrically connects with the control unit 9. The bypass unit 10 is also in fluid communication with the particulate filter unit 1 through a diverter duct 15 and a return duct 16 of the bypass unit 10. Additionally, the bypass unit 10 is electrically connected with the control unit 9 so that the control unit 9 is able to control the generated exhaust gas with respect to the particulate filter unit 1 and the bypass unit 10.
The particulate filter unit 1 generally reduces particle emissions in the generated exhaust gas. The details of how the particulate filter unit 1 reduces amount of particle emissions are known to those with ordinary skill in the art and are not discussed further herein. In reference to FIG. 3-6, the particulate filter unit 1 comprises a housing 2, an exhaust inlet 3, an exhaust outlet 4, and a diesel particulate filter (DPF) 5. More specifically, the exhaust inlet 3 and the exhaust outlet 4 are in fluid communication with the housing 2 as the exhaust inlet 3 and the exhaust outlet 4 are oppositely positioned of each other across the housing 2. The exhaust inlet 3 generally allows the generated exhaust gas to flow into the housing 2 while the exhaust outlet 4 discharges the purified exhaust gas from the housing 2. The purification of the generated exhaust gas is completed through the DPF 5, where the DPF 5 can be a single filter or a plurality of filters. More specifically, the DPF 5 is internally connected to the housing 2 in such a way that the DPF 5 is positioned in between the exhaust inlet 3 and the exhaust outlet 4. As a result, the generated exhaust gas that enters into the housing 2 is purified through the DPF 5 and then discharged through the exhaust outlet 4 as purified exhaust gas when the DPF 5 is at the activation temperature.
When the DPF 5 is at the activation temperature, the particulate filter unit 1 is able to efficiently burn off the particulate matter that accumulates within the DPF 5. However, when the DPF 5 is below the activation temperature, the particulate matter builds up within the DPF 5 as the particulate matter buildup negatively affects the functionality of the DPF 5. More specifically, the efficiency of the DPF 5 drastically reduces within the exhaust system due to the particulate matter buildup, resulting in high back pressure within the exhaust system. The bypass unit 10, which decreases the high back pressure from the exhaust system, comprises at least one at least one control valve 11 in addition to the diverter duct 15 and the return duct 16. In reference to FIG. 4 and FIG. 6, bypass unit 10 is in fluid communication with the particulate filter unit 1 so that the present invention is able to divert the generated exhaust gas away from the DPF 5 in the event that the DPF 5 is below the activation temperature. More specifically, the diverter duct 15 is in fluid communication with the exhaust inlet 3 so that the generated exhaust air can be diverted into the bypass unit 10. The at least one control valve 11 is in fluid communication with the diverter duct 15 opposite of the exhaust inlet 3 as the flow of the generated exhaust gas is controlled through the at least one control valve 11. More specifically, the at least one control valve 11 is in fluid communication with the diverter duct 15 through an input channel 12 of the at least one control valve 11. The return duct 16 is in fluid communication with the at least one control valve 11 opposite of the diverter duct 15. More specifically, the at least one control valve 11 is in fluid communication with the return duct 16 through an output channel 14 of the at least one control valve 11. In order to complete the bypass unit 10, the return duct 16 is in fluid communication with the exhaust outlet 4 opposite of the at least one control valve 11. In reference to FIG. 3-6, at least one control valve 11 further comprises an actuator 13, where the actuator 13 is operatively coupled to the at least one control valve 11. The actuator 13 allows the at least one control valve 11 to operate in between an off-position and an on-position as the actuator 13 is electrically connected to the control unit 9.
Depending on the amount of generated exhaust gas of the present invention, the bypass unit 10 can comprise multiple control valves 11 as each of the control valves 11 is control by the respective actuator 13. The input channel 12 and the output channel 14 of each of the control valves 11 are able to jointly connect with the diverter duct 15 and the return duct 16 respectively so that the control valves 11 are able to meet the increase amount of generated exhaust gas within the present invention.
The at least one pressure sensor 6 of the present invention can comprise different configurations as a sample reading measured from the at least one pressure sensor 6 is either an upstream pressure value or an upstream pressure value and a downstream pressure value. A preset value that is entered by the user of the control unit 9 is required for the functionality of the bypass unit 10 and is determined based on the allowable exhaust gas back pressure listed in the engine manufacturer's specifications.
In reference to FIG. 3-4, a first configuration of the at least one pressure sensor 6, the at least one pressure sensor 6 utilizes the inlet pressure sensor 7 and the outlet pressure sensor 8 to measure the sample readings. The inlet pressure sensor 7 is in fluid communication with the exhaust inlet 3 and positioned adjacent to the housing 2 so that the inlet pressure sensor 7 is able to measure the generated exhaust gas pressure before the generated exhaust gas is entered into the DPF 5. The outlet pressure sensor 8 is in fluid communication with the exhaust outlet 4 and positioned adjacent to the housing 2, where the outlet pressure sensor 8 is able to measure the generated exhaust gas pressure after the generated exhaust gas is existed from the DPF 5. The inlet pressure sensor 7 and the outlet pressure sensor 8 are electrically connected to the control unit 9 so that the inlet pressure sensor 7 and the outlet pressure sensor 8 are able to send out the generated exhaust gas pressure before the DPF 5 and after the DPF 5 as the sample readings to the control unit 9 respectively. More specifically, the inlet pressure sensor 7 provides the upstream pressure value while the outlet pressure sensor 8 provides the downstream pressure value to the control unit 9. Then the control unit 9 calculates a sample value from the upstream pressure value and the downstream pressure value to determine the pressure-gradient value across the DPF 5. The pressure-gradient value is then compared with the preset value so that the control unit 9 is able to determine that the bypass unit 10 needs to be activated or not. If the pressure-gradient value exceeds the preset value of the control unit 9, the at least one control valve 11 is switched into the on-position from the off-position through the actuator 13. Once the at least one control valve 11 is at the on-position, a portion of the generated exhaust gas flows through the diverter duct 15 and into the input channel 12 while the other portion of the generated exhaust gas flows into the exhaust inlet 3. The generated exhaust gas within the at least one control valve 11 is then able to flow into the return duct 16 through the output channel 14. Then the return duct 16 discharges the generated exhaust gas of the bypass unit 10 into the exhaust outlet 4. Once the pressure-gradient value falls below the preset value, the at least one control valve 11 is switched into the off-position from the on-position through the actuator 13 and the control unit 9.
In reference to FIG. 5-6, a second configuration of the at least one pressure sensor 6, the at least one pressure sensor 6 utilizes only the inlet pressure sensor 7 to measure the sample readings. The inlet pressure sensor 7 is in fluid communication with the exhaust inlet 3 and positioned adjacent to the housing 2 so that the inlet pressure sensor 7 is able to measure the generated exhaust gas pressure before the generated exhaust gas is entered into the DPF 5. The inlet pressure sensor 7 is electrically connected to the control unit 9 so that the inlet pressure sensor 7 is able to send out the generated exhaust gas pressure as the sample reading to the control unit 9. More specifically, the inlet pressure sensor 7 provides the upstream pressure value to the control unit 9. Then the control unit 9 calculates the sample value from the upstream pressure value to determine the inlet pressure value of the DPF 5. The preset value entered by the user of the control unit 9 that is required for the functionality of the bypass unit 10 is determined based on the allowable exhaust gas back pressure listed in the engine manufacturer's specifications. The preset value is then compared with the sample value so that the control unit 9 is able to determine that the bypass unit 10 needs to be activated or not. If the sample value exceeds the preset value of the control unit 9, the at least one control valve 11 is switched into the on-position from the off-position through the actuator 13. Once the at least one control valve 11 is at the on-position, a portion of the generated exhaust gas flows through the diverter duct 15 and into the input channel 12 while the other portion of the generated exhaust gas flows into the exhaust inlet 3. The generated exhaust gas within the at least one control valve 11 is then able to flow into the return duct 16 through the output channel 14. Then the return duct 16 discharges the generated exhaust gas of the bypass unit 10 into the exhaust outlet 4. Once the sample value from the upstream pressure value reaches the preset inlet pressure value, the at least one control valve 11 is switched into the off-position from the on-position through the actuator 13 and the control unit 9.
Additionally, the present invention may comprise an inlet temperature sensor and an outlet temperature sensor, where the inlet temperature sensor and the outlet temperature sensor can be jointly or individually utilized in conjunction with the at least one pressure sensor 6. In a first alternative embodiment, the present invention utilizes the inlet temperature sensor, where the inlet temperature sensor is in fluid communication with the exhaust inlet 3. Then the control unit 9 is able to measure the temperature of the generated exhaust gas through the inlet temperature sensor as the inlet temperature sensor is electrically connected with the control unit 9. In a second alternative embodiment, the present invention utilizes the outlet temperature sensor, where the outlet temperature sensor is in fluid communication with the exhaust outlet 4. Then the control unit 9 is able to measure the temperature of the purified exhaust gas or the generated exhaust gas that exists from the DPF 5 before the activation temperature through the outlet temperature sensor as the outlet temperature sensor is electrically connected with the control unit 9. In a third alternative embodiment, the present invention utilizes the inlet temperature sensor and the outlet temperature sensor, where the inlet temperature sensor and the outlet temperature sensor are in fluid communication with the exhaust inlet 3 and the exhaust outlet 4 respectively. Then the control unit 9 is able to measure the temperature of the generated exhaust gas and the purified exhaust gas or the generated exhaust gas that exits from the DPF 5 through the inlet temperature sensor and the outlet temperature sensor as the inlet temperature sensor and the outlet temperature sensor are electrically connected with the control unit 9. The control unit 9 can then use an algorithm that takes into account exhaust temperature and pressure to control the operation of the bypass unit 10. The algorithm calculates the loading of particulate matter in the DPF 5 based on the long term temperature and pressure from the sensors. When the algorithm determines that the loading of particulate matter in the DPF 5 is too high the bypass unit 10 opens.
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
Patent Application
20150226099
