US-12624655-B2 - Fuel bypass system for gaseous-fueled engine

Abstract

A method of operating a forced induction gaseous-fueled engine includes mixing gaseous-fuel and engine intake air to form a mixture at a fuel mixer. The method includes delivering the mixture to an intake manifold by at least partially bypassing a charge air cooler.

Inventors

• Steven W. CRAIG
• Andrew P. Sibrel
• Aaron J. BASKA
• Douglas R. Clement

Assignees

• GENERAC POWER SYSTEMS, INC.

Dates

Publication Date

20260512

Application Date

20241028

Claims (20)

1. 1 . A method of operating a forced induction gaseous-fueled engine, the engine comprising a charge air cooler, a compression device, a throttle valve, an intake manifold, a bypass line, and a plurality of cylinders, the method comprising: at least partially closing the throttle valve during a bypass period to deliver fuel during engine start through the bypass line to the intake manifold for delivery to the plurality of cylinders while bypassing the compression device, the charge air cooler, and the throttle valve, wherein the bypass line is upstream from an inlet of the compression device and an inlet of the charge air cooler and is downstream from the throttle valve.
2. 2 . The method of claim 1 , wherein the fuel comprises a fuel-air mixture.
3. 3 . The method of claim 1 , wherein the bypass line allows uncompressed fuel to flow via the bypass line to the intake manifold.
4. 4 . The method of claim 1 , wherein the bypass period is a time interval determined by when the engine exceeds a predetermined RPM threshold.
5. 5 . The method of claim 1 , further comprising opening the throttle valve an increasing amount during the bypass period.
6. 6 . The method of claim 1 , further comprising closing the throttle valve when completely bypassing the charge air cooler and the compression device.
7. 7 . The method of claim 1 , further comprising after bypassing the charge air cooler and the throttle valve, opening the throttle valve to transition to primary fuel system operation.
8. 8 . The method of claim 1 , wherein the engine further comprises a bypass valve positioned in communication with the bypass line, and wherein the bypass valve is opened when completely bypassing the charge air cooler.
9. 9 . The method of claim 8 , further comprising closing the bypass valve when the engine exceeds a predetermined RPM threshold.
10. 10 . The method of claim 8 , further comprising opening the bypass valve for a predetermined bypass period time interval after an initiation of a starting sequence of the engine and closing the bypass valve after a bypass period time interval has elapsed.
11. 11 . A fuel bypass arrangement for a forced induction gaseous-fueled engine, the fuel bypass arrangement comprising: a bypass line; a charge air cooler; a throttle valve; an intake manifold; a compression device; a plurality of cylinders; and a controller configured to at least partially close the throttle valve while fuel is delivered during engine start through the bypass line to the intake manifold for delivery to the plurality of cylinders, bypassing the compression device, the charge air cooler, and the throttle valve, wherein the bypass line is upstream from an inlet of the compression device and an inlet of the charge air cooler and is downstream from the throttle valve.
12. 12 . The fuel bypass arrangement of claim 11 , wherein the fuel is delivered directly to the intake manifold.
13. 13 . The fuel bypass arrangement of claim 11 , wherein the fuel comprises a fuel-air mixture.
14. 14 . The fuel bypass arrangement of claim 11 , wherein the bypass line allows uncompressed fuel to flow via the bypass line to the intake manifold.
15. 15 . The fuel bypass arrangement of claim 14 , wherein the throttle valve is positioned between, and in fluid communication with, the charge air cooler and the intake manifold, wherein the throttle valve is configured to control an amount of fuel that is delivered to the intake manifold from the charge air cooler.
16. 16 . The fuel bypass arrangement of claim 11 , further comprising a bypass valve in communication with the bypass line, the bypass valve being configured to selectively control the flow of the fuel through the bypass line.
17. 17 . The fuel bypass arrangement of claim 16 , wherein the controller is in communication with the bypass valve and automatically opens the bypass valve at an initiation of a starting sequence of the engine.
18. 18 . The fuel bypass arrangement of claim 11 , wherein after the fuel bypasses the charge air cooler and the throttle valve, the throttle valve is opened to transition to primary fuel system operation.
19. 19 . A power backup system comprising a forced induction gaseous-fueled engine, the engine comprising: a bypass line, a charge air cooler, a throttle valve, an intake manifold, a compression device, a plurality of cylinders, and a controller configured to at least partially close the throttle valve while fuel is delivered from a fuel source during engine start through the bypass line to the intake manifold for delivery to the plurality of cylinders, bypassing the compression device, the charge air cooler, and the throttle valve, wherein the bypass line is upstream from an inlet of the compression device and an inlet of the charge air cooler and is downstream from the throttle valve.
20. 20 . The power backup system of claim 19 , further comprising an electricity generating system in communication with the engine, wherein an external electrical load is connected to the electricity generating system within 10 seconds from an initiation of a starting sequence of the engine.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 18/433,168, filed on Feb. 5, 2024, which is a continuation of U.S. patent application Ser. No. 18/052,517, filed on Nov. 3, 2022, issued as U.S. Pat. No. 11,939,906, which is a continuation of U.S. patent application Ser. No. 17/108,514, filed on Dec. 1, 2020, issued as U.S. Pat. No. 11,519,325, which is a continuation of U.S. patent application Ser. No. 16/373,791, filed on Apr. 3, 2019, issued as U.S. Pat. No. 10,883,415, which claims priority to U.S. Provisional Application No. 62/652,186, filed on Apr. 3, 2018, the disclosures of which are hereby incorporated by reference in their entireties. BACKGROUND Fast start-up times are advantageous for gaseous-fueled (e.g., natural gas, propane, methane, hydrogen, well gas, and/or blends of such fuels) engines. The faster the start-up time, the sooner a load can be applied to an engine. However, this is oftentimes difficult to accomplish due to an incombustible (i.e., “stale”) fuel/air mixtures existing in the intake system from the previous operation or idleness of the gaseous-fueled engine. This is a particular problem encountered more frequently in gaseous-fueled engines, in comparison to liquid fuel engines, due to the properties of the gaseous fuel. This stale mixture is often very difficult to combust, and therefore must be exhausted (via passing it through engine cylinders) before the gaseous-fueled engine can achieve steady consistent operation. Therefore, during start-up, gaseous-fueled engines often experience a rough, or bumpy, start-up operation. In forced induction gaseous-fueled engines, fuel and intake air are mixed at a mixer and provided to a compression device (i.e., a turbocharger) for compression. Because the compression device heats up the fuel/air mixture, the fuel/air mixture is often cooled via a charge air cooler (CAC) (also known as an “intercooler”) before being delivered to an engine intake. Therefore, after shut down of the gaseous-fueled engine, the CAC includes a large amount of uncombusted mixture. The uncombusted mixture becomes stale and incombustible over time. In order to start the engine again, the incombustible contents of the CAC, and associated tubing, must be exhausted by traveling through the engine first. This can take up considerable time and increase the start-up time. In power backup systems that utilize a generator for backup power, fast start-up is desired. Because it is inefficient to constantly have the backup generator running before the generator is needed, in some examples the backup generator will be started when the power from the main power source (e.g., a power grid) goes out. In some examples, buildings often utilize a backup battery bank to supply electrical power to a building during the time period from when the main power source power supply goes out and when a backup generator starts supplying backup power. Backup battery systems are both expensive and require a storage space. Therefore, the faster the generator can start-up and supply electrical power, the smaller the backup battery bank can be, Therefore, improvements in the operation of gaseous-fueled engines are desired. SUMMARY The present disclosure relates generally to gaseous-fueled generators. In one possible configuration, and by non-limiting example, a bypass system for a gaseous-fueled generator that allows a fuel/air mixture to bypass a charge air cooler during startup is disclosed. In one example of the present disclosure, a method of operating a forced induction gaseous-fueled engine is disclosed. The method includes mixing gaseous-fuel and engine intake air to form a mixture at a fuel mixer. The method includes delivering the mixture to an intake manifold by at least partially bypassing a charge air cooler. In another example of the present disclosure, a fuel bypass arrangement for a forced induction gaseous-fueled engine is disclosed. The fuel bypass arrangement includes a compressed fuel/air mixture line that is configured to transport a compressed fuel/air mixture. The fuel bypass arrangement includes a charge air cooler positioned between, and in fluid communication with, the compressed fuel/air mixture line and a throttle valve. The charge air cooler is configured to reduce a temperature of the fuel/air mixture as the fuel/air mixture travels from an inlet to an outlet of the charge air cooler. The throttle valve is positioned between, and in fluid communication with, the charge air cooler and an intake manifold. The throttle valve is configured to control the amount of fuel/air mixture that is delivered to the intake manifold from the charge air cooler. The fuel bypass arrangement includes a bypass line in fluid communication with the compressed fuel/air mixture line, upstream from an inlet of the charge air cooler and the intake manifold and downstream from the throttle valve. The fuel bypass arrangement includes a byp