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EP-4085186-B1 - METHOD AND APPARATUS FOR ENGINE STARTUP

EP4085186B1EP 4085186 B1EP4085186 B1EP 4085186B1EP-4085186-B1

Inventors

  • LEWIS, JR., Rick Vaughan
  • LIU, Yilun
  • LIU, JINGXUAN
  • SINGH, TRIDEEP
  • LANA, CARLOS ALCIDES
  • COX, Stephen R.

Dates

Publication Date
20260506
Application Date
20191231

Claims (16)

  1. A method (200), comprising: starting (202) an internal combustion engine (102) including an intake system (106) and an air-fuel mixer (108) connected to an intake manifold (114) with first and second flow paths (110, 112); while starting the internal combustion engine (102), directing (204) an air-fuel mixture from the air-fuel mixer (108) through a controllable bypass valve (126) that is connected to the air-fuel mixer (108) to the intake manifold (114) through the second flow path (112) to bypass a compressor (118) and an intake throttle (122) in the first flow path, and positioning the intake throttle (122) in a closed position; and transitioning (210) the providing of the air-fuel mixture to the intake manifold (114) from the second flow path (112) to the first flow path (110) after the engine (102) is started, characterized in that the controllable bypass valve (126) is directly connected to the air-fuel mixer (108).
  2. The method (200) of claim 1, wherein the second flow path (112) includes a bypass with the controllable bypass valve (126), the controllable bypass valve (126) including a flanged housing (132) directly connected to the air-fuel mixer (108), the bypass including a conduit (130) connected to the flanged housing (132) opposite the air-fuel mixer (108), the conduit (130) connecting the air-fuel mixer (108) to the intake manifold (114) and starting (202) the internal combustion engine (102) includes providing the air-fuel mixture to the first flow path (110) by opening the intake throttle (122) and closing the controllable bypass valve (126).
  3. The method of claim 2, wherein starting (202) the internal combustion engine (102) includes opening the intake throttle (122) and closing the controllable bypass valve (126) in response to an air-fuel ratio associated with the first flow path (110) being within a predetermined range of an air-fuel ratio associated with the second flow path (112), and wherein opening the intake throttle (122) includes fully opening the intake throttle (122) and closing the controllable bypass valve (126) includes fully closing the controllable bypass valve (126).
  4. The method (200) of claim 2, wherein providing the air-fuel mixture to the first flow path (110) includes partially opening the intake throttle (122) while the controllable bypass valve (126) is fully open to bleed air or the air-fuel mixture into the intake manifold (114) through the intake throttle (122).
  5. The method (200) of claim 2, wherein starting (202) the internal combustion engine (102) includes injecting an initial fuel amount to provide a first air-fuel ratio at the air-fuel mixer (108) and injecting a second fuel amount at the air-fuel mixer (108) to provide a reduced, second air-fuel ratio at the air-fuel mixer (108) after injecting the initial fuel amount, and wherein each of the first and second air-fuel ratios are less than a stoichiometric air-fuel ratio.
  6. The method (200) of claim 5, further comprising injecting a stoichiometric fuel amount at the air-fuel mixer (108) in response to an air-fuel ratio associated with the first flow path (110) corresponding to an air-fuel ratio associated with the second flow path (112).
  7. An apparatus, comprising: an electronic controller (140) configured to determine a bypass valve command that controls a bypass valve actuator (128) to position a controllable bypass valve (126) in a compressor bypass flow path (112) of an internal combustion engine (102), wherein the electronic controller (140) is further configured to determine an intake throttle command that controls an intake throttle actuator (124) to position an intake throttle (122) in a compressor flow path (110) of the internal combustion engine (102) that includes a compressor (118); and wherein, in response to an engine startup condition, the bypass valve actuator (128) is operable to position the controllable bypass valve (126) in response to the compressor bypass valve command, and the intake throttle actuator (124) is operable to close the intake throttle (122) in response to the intake throttle command, to direct an air-fuel mixture from an air-fuel mixer (108) through the controllable bypass valve (126) that is connected to the air-fuel mixer (108) to an intake manifold (114) of the internal combustion engine (102) through the compressor bypass flow path (112) while closing the compressor flow path (110) to bypass the compressor (118) and the intake throttle (122) in the compressor flow path (110), characterized in that the controllable bypass valve (126) is directly connected to the air-fuel mixer (108).
  8. The apparatus of claim 7, wherein the compressor flow path (110) includes a charge air cooler (120).
  9. The apparatus of claim 7, wherein the electronic controller (140) is configured to transition the air-fuel mixture from the compressor bypass flow path (112) to the compressor flow path (110) by opening the intake throttle (122) with the intake throttle actuator (124) in response to the intake throttle command and closing the controllable bypass valve (126) with the compressor bypass valve actuator (128) in response to the bypass valve command.
  10. The apparatus of claim 9, wherein the electronic controller (140) is configured to open the intake throttle (122) and close the controllable bypass valve (126) in response to an air-fuel ratio associated with the compressor flow path (110) being within a predetermined range of an air-fuel ratio associated with the compressor bypass flow path (112).
  11. The apparatus of claim 9, wherein the electronic controller (140) is configured to transition the air-fuel mixture from the compressor bypass flow path (112) to the compressor flow path (110) by providing an intake throttle command to the intake throttle actuator (124) to partially open the intake throttle (122) while the controllable bypass valve (126) is fully open to bleed air into the intake manifold (114) of the internal combustion engine (102).
  12. The apparatus of claim 9, wherein the electronic controller (140) is configured to control an injector (134) to inject an initial fuel amount to provide a first air-fuel ratio at the air-fuel mixer (108) and inject a second fuel amount at the air-fuel mixer (108) to provide a reduced, second air-fuel ratio at the air-fuel mixer (108) after injecting the initial fuel amount, and wherein each of the first and second air-fuel ratios are less than a stoichiometric air-fuel ratio.
  13. The apparatus of claim 12, wherein the electronic controller (140) is configured to inject a stoichiometric fuel amount at the air-fuel mixer (108) in response to an air-fuel ratio associated with the compressor flow path (110) being within a predetermined range of an air-fuel ratio associated with the compressor bypass flow path (112).
  14. The apparatus of claim 7, wherein: the internal combustion engine (102) includes an intake system (106) with the air-fuel mixer (108), the air fuel mixer (108) connected to the intake manifold (114) of the internal combustion engine (102) by the compressor flow path (110) that includes the compressor (118) and the intake throttle (122), the intake system (106) further including the compressor bypass flow path (112) that includes the controllable bypass valve (126) directly connected to the air-fuel mixer (118) and connected to the intake manifold (114) with a conduit (130).
  15. The apparatus of claim 14, further comprising a charge air cooler (120) in the compressor flow path (110) and the compressor bypass flow path (112) bypasses the charge air cooler (120).
  16. The apparatus of claim 14, wherein the electronic controller (140) is configured to transition the air-fuel mixture from the compressor bypass flow path (112) to the compressor flow path (110) by opening the intake throttle (122) and closing the controllable bypass valve (126).

Description

BACKGROUND Fumigation type internal combustion engines receive a pressurized air-fuel mixture at the combustion chambers of the cylinders for engine operation. This arrangement creates a delay in engine starting during cranking of the engine since the air fuel mixture must travel from the mixer to a compressor for compression, then through a charge air cooler, and then through an intake throttle, in order to reach the intake manifold for distribution to the cylinders. As a result, starting of the engine requires a longer duration and more cranking than, for example, a direct injection engine. Certain applications for fumigation type engines employing compressed air-fuel mixtures benefit from faster start times, such as engines for generators. In addition, many fumigation type engines employ larger batteries, electric compressors, high-speed starters, compressors, and/or other components to reduce engine start times. US 2019/331020 A1 discloses a related-art engine for a generator, comprising means to reduce engine start times. However, further technological developments are desirable in this area. SUMMARY Unique systems, methods and apparatuses are disclosed for providing reduced engine startup times for a fumigation type internal combustion engine. A bypass flow path is provided that bypasses a compressor flow path, and directly connects the air-fuel mixer upstream of the compressor to the intake manifold, providing the air-fuel mixture directly to the intake manifold during engine startup. A valve is provided in the bypass flow path to open and close the bypass flow path. The need for electric compressors, high-speed starters, larger batteries, and other such components for faster engine startup may be eliminated. This summary is provided to introduce a selection of concepts that are further described below in the illustrative embodiments. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic diagram of an internal combustion engine system including an intake system with a compressor flow path with an intake throttle and a charge air cooler, and a compressor bypass flow path for engine startup.Fig. 2A is a cross-sectional view of one embodiment of a compressor bypass flow path, and Figs. 2B and 2C are graphs showing selections of compressor bypass length and diameter.Fig. 3 is a flow diagram for an engine startup procedure utilizing a compressor bypass flow path.Fig. 4 is a graphical illustration of the procedure of Fig. 3.Fig. 5 is a graphical illustration of other embodiments of engine startup procedures utilizing a compressor bypass flow path. DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. Referencing Fig. 1, an internal combustion engine system 100 for controlling a flow of an air-fuel mixture 104 is schematically depicted. The system 100 includes an internal combustion engine 102 which may be a fumigation type of engine, such as a natural gas operated spark-ignited engine. However, the present disclosure may have application with any type of engine in which fuel is injected upstream of the intake manifold and more rapid engine startup is desired. The engine 102 includes an intake system 106 that includes a first, compressor flow path 110 and a second, compressor bypass flow path 112. As discussed further below, the compressor bypass flow path 112 is employed for engine startup, while the compressor flow path 110 is employed during other engine operating conditions after engine startup. Each of the flow paths 110, 112 connects a mixer 108 that mixes the air-fuel mixture 104 to an intake manifold 114. Intake manifold 114 distributes the air-fuel mixture 104 to a plurality of cylinders 116 to initiate engine startup and for subsequent combustion during engine operations. In the illustrated embodiment, twelve cylinders 116 are provided with six cylinders in each of two cylinder banks. However, any number of cylinders 116 and cylinder arrangements in one or more cylinder banks is contemplated. The compressor flow path 110 includes a compressor 118, a charge air cooler (CAC) 120, and an intake throttle (IAT) 122 between mixer 108 and intake manifold 114. The compressor 118 operates via energy from a motor or a turbine to compress the air-fuel mixture 104 upstream of intake manifold 114. The compressed air-fuel mixture 104 is sometimes called charge air, charge gases, charge flow, intake air, or other terms, none of which are limiting. The compressed air-fuel mixture 10