WO2019115716A1

WO2019115716A1 - Supercharger active intra-cooling apparatus

Info

Publication number: WO2019115716A1
Application number: PCT/EP2018/084809
Authority: WO
Inventors: JR. Bradley K. WRIGHT
Original assignee: Eaton Intelligent Power Limited
Priority date: 2017-12-15
Filing date: 2018-12-13
Publication date: 2019-06-20

Abstract

A super charger assembly includes a supercharger having a housing including an air inlet and an air outlet linked by an air chamber. Rotors are disposed in the air chamber. At least one port is formed in the supercharger housing between the inlet and the rotors. An intercooler is coupled to the outlet. The intercooler includes at least one conduit coupled to the at least one port transmitting cooled air to the supercharger.

Description

SUPERCHARGER ACTIVE INTRA-COOLING APPARATUS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. provisional application number 62/599,061 filed on December 15, 2017 which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The invention relates to superchargers and with more particularity to superchargers having an intra-cooled air feed that is actively controlled.

BACKGROUND OF THE INVENTION

[0003] A supercharger may be utilized to supply compressed air to a combustion engine. When the air is compressed, then more air can be supplied, enabling a vehicle to produce more power.

[0004] A Roots type supercharger is a positive displacement pump that forces air around the outer circumference of rotors and blows the air into the intake manifold of an engine. The Roots type supercharger has two counter-rotating lobed rotors. The two rotors trap air in the gaps between rotors and push it against the housing as the rotors rotate towards the outlet into the engine's intake manifold. By moving air into the manifold at a higher rate than the engine consumes it, pressure is built.

[0005] The Roots blower receives air from a low pressure suction side and moves this air to a high pressure outlet side. When the low pressure air received by the Roots supercharger comes in contact with the high pressure outlet side, then a backflow event takes place whereby the high pressure gas from the outlet backflows into the supercharger to compress the low pressure gas into higher pressure gas. Compression of gas in the supercharger generates heat and the higher the pressure ratio the more heat will be generated. At higher pressure ratios such as above 2.4, heat generated may be above an operating threshold of the supercharger.

[0006] At higher pressure ratios, it may be desirable to cool the Roots compressor by using relatively colder high pressure gas available after the intercooler that is routed to the intake of the supercharger. However, constant circulation of the air from the inter-cooler would result in the supercharger doing more work than required and lower an overall efficiency of the engine and supercharger system. There is therefore a need in the art for a system and process that may control an amount of cooled air from an intercooler back into the intake of the supercharger based on the operating conditions of the supercharger. There is a further need for a system and process that may provide an increased pressure ratio and lower operating temperature for increasing the efficiency of the supercharger while providing control to adjust the amount of air based on operating parameters and loads of the supercharger.

SUMMARY OF THE INVENTION

[0007] In one aspect there is disclosed a super charger assembly that includes a supercharger having a housing including an air inlet and an air outlet linked by an air chamber. Rotors are disposed in the air chamber. At least one port is formed in the supercharger housing between the inlet and the rotors. An intercooler is coupled to the outlet. The intercooler includes at least one conduit coupled to the at least one port transmitting cooled air to the supercharger.

[0008] In another aspect there is disclosed a super charger assembly that includes a supercharger having a housing including an air inlet and an air outlet linked by an air chamber. Rotors are disposed in the air chamber. At least one port is formed in the supercharger housing between the inlet and the rotors. An intercooler is coupled to the outlet. The intercooler includes at least one conduit coupled to the at least one port transmitting cooled air to the supercharger. The at least one port includes a shape having a taper expanding in a direction of rotation of the rotors.

[0009] In a further aspect there is disclosed_a super charger assembly that includes a supercharger having a housing including an air inlet and an air outlet linked by an air chamber. Rotors having four lobes are disposed in the air chamber. At least one port is formed in the supercharger housing between the inlet and the rotors. An intercooler is coupled to the outlet.

The intercooler includes at least one conduit coupled to the at least one port transmitting cooled air to the supercharger. The at least one port includes a shape having a taper expanding in a direction of rotation of the rotors. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic representation of a supercharger, intercooler, engine and a recirculation path for routing intercooled air back to an intake of the supercharger;

[0011] Figure 2 is a partial perspective view of a super charger detailing the structure and flow path of air from the intercooler into the intake of the supercharger and the high pressure air exiting the supercharger;

[0012] Figure 3 is an end view of a supercharger detailing the ports for routing the intercooled air into the supercharger;

[0013] Figure 4 is a schematic representation of a control structure for a valve regulating a flow of intercooled air back into the supercharger;

[0014] Figure 5 is a plot of the isentropic compressor efficiency as a function of the supercharger rpm at a pressure ratio of 1.4 for varying flowrates and temperatures of intercooled air;

[0015] Figure 6 is a plot of the isentropic compressor efficiency as a function of the supercharger rpm at a pressure ratio of 1.8 for varying flowrates and temperatures of intercooled air;

[0016] Figure 7 is a plot of the isentropic compressor efficiency as a function of the supercharger rpm at a pressure ratio of 2.2 for varying flowrates and temperatures of intercooled air;

[0017] Figure 8 is a plot of the isentropic compressor efficiency as a function of the supercharger rpm at a pressure ratio of 2.4 for varying flowrates and temperatures of intercooled air; [0018] Figure 9 is a plot of the isentropic compressor efficiency as a function of the supercharger rpm at a pressure ratio of 2.8 for varying flowrates and temperatures of intercooled air;

[0019] Figure 10 is a sectional view from the inlet detailing the rotors and ports;

[0020] Figure 1 1 is a sectional view from the inlet detailing the rotors and ports;

[0021] Figure 12 is a sectional view from the inlet detailing the rotors and ports;

[0022] Figure 13 is a table detailing parameters for various rotors and ports at 12,000 rpm and at a pressure ratio of 2.8;

[0023] Figure 14 is a table detailing parameters for various rotors having various twists and the port of figure 12 at 12,000 rpm and at a pressure ratio of 2.8;

[0024] Figure 15 is a table detailing parameters for various rotors and the port of figure 12 at 12,000 rpm and at a pressure ratio of 1.6;

[0025] Figure 15 is a table detailing parameters for various rotors and the port of figure 12 at 12,000 rpm and at a pressure ratio of 3.6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Referring to Figures 1-3, there is depicted a supercharger 12 coupled to an intercooler 14 and an engine 16. Figure 1 shows a supercharger system for regulating the outlet parameters of the supercharger 12 by introducing intercooled air into the backflow air of the supercharger 12. Supercharger 12 includes an air inlet 18, an air chamber 20, and an outlet 22.

[0027] When operating, the supercharger 12 heats air as it passes through the air chamber 20. Supercharger 12 is utilized to compress air going to engine 16 and to increase the power output of the engine 16. The introduction of cooled air from the intercooler 14 increases the pressure ratio of the supercharger system over prior art methods. The pressure ratio describes the amount of boost the supercharger can supply to the engine, and is the ratio of the fluid pressure before the supercharger to the fluid pressure after the supercharger. Currently, the pressure ratio of a supercharger is limited by the maximum operating temperature of the device. The reduction of the temperature of gas in the supercharger allows an increased pressure ratio while maintaining a temperature that is within the temperature threshold of the supercharger 12. By providing cooled air from the intercooler 14 to the supercharger 12, the pressure ratio of the supercharger 12 increases while reducing the temperature of the discharged air from the supercharger 12.

[0028] Again referring to Figure 1, the system includes conduits 24 that lead from the intercooler 14 back to the supercharger 12. The conduits 24 include control valves 26 that are utilized to control an amount of cooled air from the intercooler 14 that is routed back to the inlet of the supercharger 12. In one aspect, the valves 26 are positioned close to the rotors 28 of the supercharger 12 to minimize the volume of air that may be regulated by the valves 26 when the valves 26 are actuated. In one aspect, the valves 26 may be positioned from 1 to 1000 mm from the rotors 28. Various valves such as electronically controlled bypass valves or multi-position solenoid valves may be utilized.

[0029] The cooled air from the intercooler 14 is introduced into ports 30 formed in the supercharger 12. The ports 30 are formed in the supercharger housing between the inlet 18 and the rotors 28 such that cooled air can be transferred between lobes of the rotors 28.

[0030] The depicted system includes a control system 32 for controlling the amount of air recirculated from the intercooler 14 to adjust the temperature of the supercharger and maintain an efficient operation of the supercharger 12, as best seen in Figure 4. The control system 32 includes sensors 34 capable of sensing conditions and of sending signals, such as temperature, pressure, speed, air flow, mass flow or volumetric flow. The control system 32 also includes a control unit 36 which includes a computer processor, communication ports, memory, and programming and is linked with the sensors 34. The control unit 36 may be a portion of an engine control unit (ECU). The control system 32 may also include an actuator 38 that adjusts a position of the valve 36 and adjusts the valve 36 a part of a process to regulate the amount of cooled air delivered to the inlet 18 or port 30 of the supercharger 12 to maintain efficient operation at various pressure ratios and engine speeds. Various actuators such linear actuators or rotary actuators may be utilized.

[0031] Examples

[0032] Testing of various flow rates of air from an inter cooler was performed on a testing apparatus including a modified V550 supercharger at varying flow rates and temperatures. The testing was completed with an inline torque transducer measuring torque directly at the input of the supercharger. The testing apparatus is instrumented with thermocouples on inlet air, outlet air, recirculation air, intercooler water, room temp, and supercharger gear case. Pressure transducers measure inlet pressure, outlet pressure, and room pressure. Outlet pressure of the supercharger is controlled by a valve to limit flow after the supercharger. The intra-cooling flowrate or flow of air from the intercooler back to the inlet of the supercharger was controlled by a block off plate with a hole drilled to limit the estimated flow rate to approximately 50%. Measurements were also performed for 0% and 100% flow rates. [0033] Calculations using the collected data were utilized to calculate an isentropic compressor efficiency of the testing apparatus at various flow rates, pressure ratios and temperatures. The isentropic compressor efficiency may be utilized as a representation of how efficient the supercharger operates in comparison to an idealized isentropic device that operates thermodynamically both adiabatically and reversibly. The data is graphically represented in Figures 5-10.

[0034] Referring to Figure 5, there is shown a plot of the isentropic compressor efficiency of the testing apparatus at various flow rates and temperatures at a pressure ratio of 1.4 as a function of the rpm of the supercharger. As can be seen in the plot, the 50% flow rate at 40 degrees C has the highest efficiency at rpm of from 5,000 to about 18,000 rpm. This result is unexpected as at a lower pressure ratio there is less heat generated and the loss in work from moving additional mass flow would be expected to outweigh the benefit of the cooling of the additional mass flow. At rpm of from 18,000 to about 23,000 the 100% flow rate at 60 degrees C has a slightly higher efficiency.

[0035] Referring to Figure 6, there is shown a plot of the isentropic compressor efficiency of the testing apparatus at various flow rates and temperatures at a pressure ratio of 1.8 as a function of the rpm of the supercharger. As can be seen in the plot, the 50% flow rate at 40 degrees C has a slightly lower efficiency at rpm of from 5,000 to about 23,000 rpm. In comparison to the 0% flow rate.

[0036] Referring to Figure 7, there is shown a plot of the isentropic compressor efficiency of the testing apparatus at various flow rates and temperatures at a pressure ratio of 2.2 as a function of the rpm of the supercharger. As can be seen in the plot, the 50% flow rate at 40 degrees C has the highest efficiency at rpm of from 10,000 to about 20,000 rpm. At rpm of 5,000 to about 10,000, the 0% flow rate has a slightly higher efficiency.

[0037] Referring to Figure 8, there is shown a plot of the isentropic compressor efficiency of the testing apparatus at various flow rates and temperatures at a pressure ratio of 2.4 as a function of the rpm of the supercharger. As can be seen in the plot, the 50% flow rate at 40 degrees C has the highest efficiency at rpm of from 5,000 to about 21 ,000 rpm.

[0038] Referring to Figure 9, there is shown a plot of the isentropic compressor efficiency of the testing apparatus at various flow rates and temperatures at a pressure ratio of 2.8 as a function of the rpm of the supercharger. As can be seen in the plot, the 50% flow rate at 40 degrees C has the highest efficiency at rpm of from 10,000 to about 21,000 rpm.

[0039] As can be seen from the above discussion, various flow rates will provide a higher efficiency at different operating conditions such as at different pressure ratios and rpm of the supercharger. It would therefore be beneficial to adjust the flow rate dynamically to provide the most efficient operation of the supercharger at various conditions. The flow rate may be adjusted using the control system 32, actuator 38 and structure as described above.

[0040] Referring to figures 10-12, there are shown partial sectional views from the inlet 18 of the supercharger 12 showing the rotors 28 and the ports 30. In one aspect, the rotors 30 may have a plurality of lobes 38 including a cycloidal profile 40. The cycloid profile 40 provides an efficient profile by reducing leakage area and the displacement ratio in comparison to an involute profile. The rotors 28 may include from 3 to 5 lobes 38 with four lobes 38 shown in the figures.

In one aspect, the four lobe rotor 28 may be utilized which offers an increase seal time in comparison to a 3 lobe rotor. The rotors may include various twists which may range from 85 to 115 degrees, as will be discussed in more detail below.

[0041] The ports 30 may be positioned and formed on the housing such that desired port timing may be achieved relative to the rotors 28 for the air introduced from the intercooler. The port timing relative to the rotors 28 may be from 20 to 45 degrees.

[0042] The ports 30 may have various shapes having a specified area to control the amount of cooled air routed from the intercooler to the rotors 28 as described above. The various shapes also control the rate at which cooled air is introduced between the lobes 38 of the rotors 28. In one aspect, the shapes may be non uniform such that they include a taper or relatively smaller area 42 that expands in a direction of rotation of the rotors. The controlled introduction of air from the intercooler 14 into the rotors 28 has been found to increase the isentropic efficiency of the supercharger 12 at various pressure ratios.

[0043] Referring to Figure 10, the port 30 includes an arcuate elliptical shape. This profile shall be designated as IP03 in the tables presented in Figures 13-16.

[0044] Referring to Figure 11 , the port 30 includes a taper 42 in the form of an arc 44 coupled to an oval body 46. This profile shall be designated as IP 10 in the tables presented in Figures 13-16.

[0045] Referring to Figure 12, the port 30 includes arcuate triangular shape 48 having a taper 42 in the form of an arc 50 coupled to a triangular body 52. This profile shall be designated as IP 11 in the tables presented in Figures 13-16.

[0046] Referring to Figure 13, there is presented a table detailing data calculated from computational fluid dynamic models for various rotors and ports at 12,000 rpm and at a 2.8 pressure ratio. The data was gathered using ANSYS software. As can been seen in Figure 13 various specifications of the rotors and the flow characteristics of the supercharger are provided. The columns including the R730FE, R730 and 4 lobe are provided for comparative purposes and provide comparative data for various rotors where no intra-cooled air is introduced from the intercooler to the supercharger. As can be seen in the table, the IP03, IP 10 and IP11 ports utilized for intra-cooling have isentropic compressor efficiencies that are close in comparison to the comparative rotors. The IP 10 and IP1 1 examples have isentropic compressor efficiencies within 7% of the highest of the comparison examples (R730FE). The IP03 example has isentropic compressor efficiency within 11% of the highest of the comparison examples (R730FE). This small difference in efficiencies is achieved with a lower torque and power consumption while maintaining a relatively low temperature.

[0047] Referring to Figure 14, there is presented a table detailing data calculated from computational fluid dynamic models for various rotors and ports at 12,000 rpm and at a 2.8 pressure ratio with various rotor twists and having the IP11 port shown in figure 12. The data was gathered using ANSYS software. As can been seen in Figure 14 various specifications of the rotors and the flow characteristics of the supercharger are provided. The columns including the R730FE, and R730 are provided for comparative purposes and provide comparative data for various rotors where no intra-cooled air is introduced from the intercooler to the supercharger. As can be seen in the table, the twists for intra-cooling have isentropic compressor efficiencies that are close in comparison to the comparative rotors. The 100 degree twist has the highest isentropic compressor efficiency of the itra-cooled examples. The 85 and 100 degree twists are within 7% of the highest of the comparison examples (R730FE). The 115 degree example has isentropic compressor efficiency within 11% of the highest of the comparison examples

(R730FE). This small difference in efficiencies is achieved with a lower torque and power consumption while maintaining a relatively low temperature.

[0048] Referring to Figure 15, there is presented a table detailing data calculated from computational fluid dynamic models for various rotors and ports at 12,000 rpm and at a 1.6 pressure ratio and having the IP1 1 port shown in figure 12. The data was gathered using ANSYS software. As can been seen in Figure 15 various specifications of the rotors and the flow characteristics of the supercharger are provided. The columns including the R730FE, R730 and 4 lobe are provided for comparative purposes and provide comparative data for various rotors where no intra-cooled air is introduced from the intercooler to the supercharger. As can be seen in the table, the IP1 1 port utilized for intra-cooling have isentropic compressor efficiencies that are close in comparison to the comparative rotors. The IP 10 and 1P1 1 examples have isentropic compressor efficiencies within 8% of the highest of the comparison examples (R730). This small difference in efficiencies is achieved with a lower torque and power consumption while maintaining a relatively low temperature.

[0049] Referring to Figure 16, there is presented a table detailing data calculated from computational fluid dynamic models for various rotors and ports at 12,000 rpm and at a 3.6 pressure ratio and having the IP11 port shown in figure 12. The data was gathered using ANSYS software. As can been seen in Figure 16 various specifications of the rotors and the flow characteristics of the supercharger are provided. The columns including the V566 and 4 lobe are provided for comparative purposes and provide comparative data for various rotors where no intra-cooled air is introduced from the intercooler to the supercharger. As can be seen in the table, the IP1 1 port utilized for intra-cooling have isentropic compressor efficiencies that exceed the comparative V566 rotors. This increase in efficiency is achieved with a lower torque and power consumption while maintaining a relatively low temperature.

[0050] I claim:

Claims

Claims:

1. A super charger assembly comprising:

a supercharger having a housing including an air inlet and an air outlet linked by an air chamber;

rotors disposed in the air chamber;

at least one port formed in the supercharger housing between the inlet and the rotors; an intercooler coupled to the outlet, the intercooler including at least one conduit coupled to the at least one port transmitting cooled air to the supercharger.

2. The supercharger assembly of claim 1 including at least one control valve disposed in the at least one conduit, the at least one valve regulating a volume of air routed from the intercooler to the at least one port controlling the temperature of the supercharger.

3. The supercharger assembly of claim 1 wherein the at least one port includes 2 ports.

4. The supercharger assembly of claim 1 wherein the at least one valve includes two valves.

5. The supercharger assembly of claim 1 wherein the at least one valve is positioned proximate the rotors from 1 to 1000 mm.

6. The supercharger assembly of claim 1 wherein the at least one port is positioned between the inlet and rotors wherein air from the intercooler is introduced between lobes formed on the rotors.

7. The supercharger assembly of claim 1 further including a control system having a control unit linked with sensors and an actuator.

8. The supercharger assembly of claim 7 wherein the actuator adjusts a position of the at least one valve regulating a volume of air from the intercooler delivered to the at least one port.

9. A super charger assembly comprising:

rotors disposed in the air chamber;

at least one port formed in the supercharger housing between the inlet and the rotors; an intercooler coupled to the outlet, the intercooler including at least one conduit coupled to the at least one port transmitting cooled air to the supercharger;

wherein the at least one port includes a shape having a taper expanding in a direction of rotation of the rotors.

10. The supercharger assembly of claim 9 wherein the port timing relative to the rotors is from 20 to 45 degrees.

11. The supercharger assembly of claim 9 wherein the rotors include a cycloidal profile having from 3 to 5 lobes.

12. The supercharger assembly of claim 9 wherein the rotors include 4 lobes and have a twist of from 85 to 115 degrees.

13. The supercharger assembly of claim 9 wherein the at least one port includes 2 ports.

14. The supercharger assembly of claim 9 wherein the port includes a taper in the form of an arc coupled to an oval body.

15. The supercharger assembly of claim 9 wherein the port includes an arcuate elliptical shape.

16. The supercharger assembly of claim 9 wherein the port includes an arcuate triangular shape having a taper in the form of an arc coupled to a triangular body.

17. A super charger assembly comprising:

rotors disposed in the air chamber wherein the rotors include 4 lobes;

wherein the at least one port includes a shape having a taper expanding in a direction of rotation of the rotor.

18. The supercharger assembly of claim 17 wherein the port includes an arcuate triangular shape having a taper in the form of an arc coupled to a triangular body.

19. The supercharger assembly of claim 18 wherein the super charger has an isentropic efficiency greater than 44 % at 12,000 rpm and at a 3.6 pressure ratio.

20. The supercharger assembly of claim 18 wherein the super charger has an isentropic efficiency greater than 52 % at 12,000 rpm and at a 2.8 pressure ratio.