CROSS-REFERENCE TO RELATED APPLICATIONS

[00011 This application claims priority to U.S. provisional application number 62735949 filed on September 25, 2018 which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The invention relates to exhaust gas recirculation (EGR) pumps and a cleaning and injection system for an EGR pump.

BACKGROUND OF THE INVENTION

[0003] Water vapor may be included in exhaust gases from an engine because of the combustion process of fuel supplied to the engine. Generally, the water vapor is expelled to the environment through an exhaust system. However, in an EGR application a portion of the exhaust is recirculated to the engine intake manifold. The water vapor may provide a carrier for particulate matter such as soot and may react with other components of the exhaust to form an acidic composition. The EGR stream including the particulate matter and acidic composition may degrade the performance of an EGR pump. It is therefore desirable to remove and or neutralize deposits and regulate the inlet conditions to an EGR pump to prevent degradation of the performance of the EGR pump. SUMMARY OF THE INVENTION

[0004] In one aspect, there is disclosed an EGR system for an engine that includes an engine producing exhaust gas. An EGR pump moves the exhaust gas to an intake manifold of the engine. A source of fresh air is connected with the EGR pump. The exhaust gas and fresh air are combined and compressed in the EGR pump prior to entry into the intake manifold of the engine.

[0005] In another aspect, there is disclosed an EGR system for an engine that includes an engine producing exhaust gas. An EGR pump moves the exhaust gas to an intake manifold of the engine. A source of fresh air is coupled to a compressor providing a pressurized air source to the EGR pump. The exhaust gas and fresh air are combined and compressed in the EGR pump prior to entry into the intake manifold of the engine and the pressurized air removes soot from the EGR pump.

[0006] In a further aspect, there is disclosed an EGR system for an engine that includes an engine producing exhaust gas. An EGR pump moves the exhaust gas to an intake manifold of the engine. A cleaning liquid is connected to a pump that pumps the cleaning liquid into the EGR pump. A source of fresh air is connected with the EGR pump. The exhaust gas and fresh air are combined and compressed in the EGR pump prior to entry into the intake manifold of the engine and the cleaning liquid removing soot from the EGR pump.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a diagram of an EGR system detailing an engine, EGR cooler, fresh air and EGR pump;

[0008] Figure 2 is a diagram of an EGR system detailing an engine, EGR cooler, compressor and EGR pump; [0009] Figure 3 is a diagram of an EGR system detailing an engine, EGR cooler, water source, injector and EGR pump;

[0010] Figure 4 is a diagram of an EGR system detailing an engine, EGR cooler, alkaline solution source, injector and EGR pump;

[0011] Figure 5 is a diagram of an EGR system detailing an engine, EGR cooler, detergent source, injector and EGR pump.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Referring to Figure 1, there is shown a diagram of an EGR system including an EGR pump 10. The EGR system includes an engine 12 having an intake manifold 14 and an exhaust manifold 16. A portion of the exhaust gases 17 from the exhaust manifold 16 may be utilized in an EGR system. In the depicted embodiment, the exhaust gases 17 may be routed to a valve 18 which can control flow of the EGR gases into a first stream 20 that is routed to an EGR cooler 22 to adjust a temperature of the EGR stream 20. Alternatively, the EGR gas may bypass the EGR cooler 22 as a stream 24. The higher temperature EGR stream 24 may prevent accumulation of soot due to water condensation. In one aspect, a combination of streams 20 and 24 may be utilized. Either of the streams 24, 26 is next routed to the EGR pump 10 and combined with a fresh air charge 28. The compressed charge is then routed from the outlet 30 of the EGR pump 10 to the intake manifold 14 of the engine 12.

Referring to Figure 2, there is shown a diagram of an EGR system including an EGR pump 10. The embodiment of Figure 2 is the same as that described above in Figure 1 and includes a compressor 32. The compressor 32 may supply a pressurized charge of air 29 into the EGR pump 10 to remove soot deposits from components of the EGR pump 10. The compressor 32 provides a pressurized air source wherein the pressurized air is introduced into the EGR pump 10 when an air pressure from the pressurized charge of air 29 exceeds an exhaust gas pressure.

The compressor 32 may be associated with air tanks 33 such as on a heavy track that store pressurized air for use in vehicle systems. The pressurized air charge 29 may be provided during specified operating conditions of the engine 12. In one aspect, the pressurized air 29 may be provided during an engine shut down. The pressurized air is introduced during shutdown and the EGR pump is spun in reverse during shutdown or after shutdown for a short time period to promote soot removal.

[0013] The pressurized air 29 may be delivered as a pulse through rotors of the EGR pump 10. The pulse may have various durations and numbers of pulses. The pulses may have a specified duration such as from 2 to 3 seconds or may be longer such as 10 seconds. Additionally the pulses may be sequenced such as a pulse followed by a pause and then another pulse. The sequence may have various duration pauses such as from 1 to 10 seconds and have various numbers of pulses. In one aspect, the pressurized air 29 may be delivered from an air tank 33 based upon a state of the air in the air tank 33. For example, the compressed air may be delivered to the EGR pump 10 if the air tanks has more than 50% pressure or more than 75% or from 90 to 100% pressure. The pressure being the full pressure capacity of the air tank.

[0014] The pressurized air charge 29 may be provided during idle operation of the engine 12 when the engine 12 is warm. The pulse may have various durations and numbers of pulses. The pulses may have a specified duration such as from 2 to 3 seconds or may be longer such as 10 seconds. Additionally the pulses may be sequenced such as a pulse followed by a pause and then another pulse. The sequence may have various duration pauses such as from 1 to 10 seconds and have various numbers of pulses. In one aspect, the pressurized air 29 may be delivered from an air tank 33 based upon a state of the air in the air tank 33. For example, the compressed air may be delivered to the EGR pump 10 if the air tanks has more than 70% pressure or more than 80% or from 90 to 100% pressure.

[0015] The pressurized air charge 29 may be provided during low load operation of the engine 12 such as when the engine 12 is operating below 3 to 4 bar BMEP. In one aspect, during low load the pressure in the air tanks 33 may be checked to see if the pressure is greater than an intake manifold pressure. The pulse may have various durations and numbers of pulses. The pulses may have a specified duration such as from 2 to 3 seconds or may be longer such as 10 seconds. Additionally the pulses may be sequenced such as a pulse followed by a pause and then another pulse. The sequence may have various duration pauses such as from 1 to 10 seconds and have various numbers of pulses. In one aspect, the pressurized air 29 may be delivered from an air tank 33 based upon a state of the air in the air tank. For example, the compressed air may be delivered to the EGR pump 10 if the air tanks has more than 50% pressure or more than 75% or from 90 to 100% pressure.

[0016] In one aspect, the pulses may be delivered to the EGR pump when the compressor is on and after the pressure in the air tank has reached 95% pressure in any of the above described engine states. Additionally, the air compressor may remain on for an additional time until the tank pressure reaches a pressure of 100%. An actuator 35 for timing the air pulses may be controlled by pulse width modulation or may be controlled in an on or off state.

[0017] In one aspect, the pressurized air 29 may be delivered through a nozzle 37 that directs the pressurized air to an inlet portion of the rotors. [0018] Referring to Figure 3, there is shown a diagram of an EGR system including an EGR pump 110. The EGR system includes an engine 112 having an intake manifold 114 and an exhaust manifold 116. A portion of the exhaust gases 117 from the exhaust manifold 1 16 are routed to an EGR cooler 118 to adjust a temperature of the EGR stream 117. The stream 120 exiting the EGR cooler 118 is next routed to the EGR pump 110. A cleaning liquid in this case a water source 122 is coupled to a pump 124 and valve 126 for supplying water to an injector 128. The water from the injector is combined with a charge of fresh air 129 and routed to an inlet 130 of the EGR pump 110. When the temperature of the inlet 130 to the EGR pump 110 exceeds the boiling point, the water will be provided as steam to clean the components within the EGR pump 110 and dilute several of the components within the EGR gases. The compressed charge is then routed from the outlet 132 of the EGR pump 110 to the intake manifold 114 of the engine 112.

[0019] Referring to Figure 4, there is shown a diagram of an EGR system including an EGR pump 110. The EGR system includes an engine 112 having an intake manifold 114 and an exhaust manifold 116. A portion of the exhaust gases 117 from the exhaust manifold 116 are routed to an EGR cooler 118 to adjust a temperature of the EGR stream 117. The stream 120 exiting the EGR cooler 1 18 is next routed to the EGR pump 110. A cleaning liquid in this case an alkaline solution 121 is coupled to a pump 124 and valve 126 for supplying solution to an injector 128. The alkaline solution 121 from the injector 128 is combined with a charge of fresh air 129 and routed to an inlet 130 of the EGR pump 110. The alkaline solution may change the acidic components within the EGR gases to a more neutral pH and reduce wear and corrosion on the components of the EGR pump. The compressed charge is then routed from the outlet 132 of the EGR pump 110 to the intake manifold 114 of the engine 112. [0020] Referring to Figure 5, there is shown a diagram of an EGR system including an EGR pump 110. The EGR system includes an engine 112 having an intake manifold 1 14 and an exhaust manifold 116. A portion of the exhaust gases 1 17 from the exhaust manifold 116 are routed to an EGR cooler 118 to adjust a temperature of the EGR stream 1 17. The stream 120 exiting the EGR cooler 1 18 is next routed to the EGR pump 110. A cleaning liquid in this case a detergent source 123 is coupled to a pump 124 and valve 126 for supplying detergent to an injector 128. The detergent from the injector 128 is combined with a charge of fresh air 129 and routed to an inlet 130 of the EGR pump 110. The detergent may be utilized to clean the components within the EGR pump 110 and dilute several of the components within the EGR gases. Various detergent compositions may be utilized. The compressed charge is then routed from the outlet 132 of the EGR pump 1 10 to the intake manifold 1 14 of the engine 1 12.