Patent Application
20150027416
The present disclosure relates to a fuel delivery system having a fuel pump in an engine.
Fuel pumps are used in engine's to pressurize fuel in a fuel delivery system. Some fuel delivery systems are designed for high pressure fuel delivery for direct injection systems. Magnetic solenoid valves (MSV) are utilized in fuel pumps to regulate the fuel flow into a pump chamber during fuel pump operation. Specifically, solenoid valves in fuel pumps may be operated to selectively permit and inhibit fuel flow into a pump chamber from a fuel pump inlet. As a result, the pump chamber may receive fuel from the inlet during an intake stroke and deliver pressurized fuel to downstream components during a delivery stroke.
US 2011/0097228 discloses a high pressure fuel pump having multiple solenoid valves for adjusting the amount of fuel delivered to a fuel rail from the high pressure fuel pump However, the solenoid valve disclosed in US 2011/0097228 may generated ticks, vibrations, etc., during pump operation when the solenoid valve is activated. Therefore, noise, vibration, and harshness (NVH) may be increased in the engine via the high pressure fuel pump disclosed 2011/0097228 and other fuel pumps utilizing solenoid valves. The NVH may not only harm the fuel pump but may also degrade surrounding components. As a result, customer satisfaction may be decreased, component longevity may also be deceased, and the likelihood of component failure may be increased when NVH is generated by the solenoid valve.
The inventors herein have recognized the above issues and developed a method of pressuring fuel for a direct injection fuel system via a fuel pump in an engine. The method includes, during a first mode, adjusting a magnetic solenoid valve (MSV) to control pump outlet pressure and during a second mode, deactivating the MSV and controlling pump outlet pressure via a noise-reducing valve assembly on an inlet side of the fuel pump.
In this way, the solenoid valve in the fuel pump may be disabled for a selected period of time, such as idle or other selected operating conditions while the noise-reducing valve functions to control the pump outlet pressure. Thus, the window of operation of the solenoid valve is decreased, thereby decreasing NVH in the pump generated by the solenoid valve. As a result, component longevity and customer satisfaction are increased. Further it will be appreciated that in some examples the noise-reducing may be passively actuated. Therefore, the noise-reducing valve may generate a small amount of (e.g., substantially zero) NVH when compared to the solenoid valve. Consequently, the technical results achieved via the fuel pump include reducing the NVH generated in the pump during certain operating conditions, such as during idle and/or other low speed conditions, while still providing sufficient pressure control and fuel supply to the fuel pump so that sufficient fuel can be delivered to the engine.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. Additionally, the above issues have been recognized by the inventors herein, and are not admitted to be known.
A fuel pump for an engine is described herein. The fuel pump is configured to reduce noise, vibration, and harshness (NVH) generated via the fuel pump. The fuel pump includes a noise-reducing valve that enables a magnetic solenoid valve (MSV) to be deactivated during certain time intervals of fuel pump operation. For instance, the MSV may be deactivated in an open positioned during a delivery stroke and/or during idle operation when the engine is operating below a threshold speed. In this way, the window of operation of the solenoid valve is decreased, thereby decreasing NVH in the pump generated by the solenoid valve. As a result, the longevity of the fuel pump and the surrounding components is increased and customer satisfaction is also increased.
The engine 12 includes at least one cylinder 14. However, engines having different cylinder configurations have been contemplated. For instance, the cylinder may be arranged in an inline configuration where the cylinders are positioned in a straight line, a horizontally opposed configuration, a V-configuration, etc.
An intake system 16 is configured to provide air to the cylinder 14. The intake system 16 may include a variety of components for achieving the aforementioned functionality such as a throttle, an intake manifold, compressor, intake conduits, etc. As shown, the intake system 16 is in fluidic communication with the cylinder 14, denoted via arrow 18. It will be appreciated that one or more conduits, passages, etc., may provide the fluidic communication denoted via arrow 18. An intake valve 20 included in the intake system 16 may provide the fluidic communication between the intake system and the cylinder. The intake valve 20 may be cyclically opened and closed to implement combustion operation in the engine.
Furthermore, the engine further includes an exhaust system 22 configured to receive exhaust gas from the cylinder 14. The exhaust system may include manifolds, conduits, passages, emission control devices (e.g., catalysts, filters, etc.), mufflers, etc. An exhaust valve 24 coupled to the cylinder 14 is included in the exhaust system 22. The exhaust valve 24 may be configured to cyclically open and close during combustion operation. The exhaust system 22 is in fluidic communication with the cylinder 14, denoted via arrow 26. Specifically, arrow 26 may indicate exhaust passages, conduits, etc., providing fluidic communication between the cylinder 14 and the exhaust valve 24. The exhaust valve may be configured to cyclically open and close to enable combustion operation.
The vehicle 10 further includes a fuel delivery system 30. The fuel delivery system 30 having a fuel tank 32 and a first fuel pump 34 (e.g., low pressure fuel pump) configured to flow fuel to downstream components. The fuel tank 32 stores a liquid fuel 35 (e.g., gasoline, diesel, ethanol, etc.). The fuel delivery system 30 further includes a second fuel pump 36 (e.g., a high pressure fuel pump). The second fuel pump 36 is in fluidic communication with a fuel rail 40 and a fuel injector 42. It will be appreciated that in other examples the fuel delivery system may include a single fuel pump. A fuel rail 40 is positioned downstream of the second fuel pump 36 and therefore is in fluidic communication with the second fuel pump. A fuel injector 42 is positioned downstream of the fuel rail 40 and therefore is in fluidic communication with the fuel rail 40. The fuel injector 42 is shown directly coupled to the cylinder 14 providing what is known as direct injection. Additionally or alternatively, a port fuel injector may be included in the fuel delivery system configured to provide fuel to an intake conduit upstream of the intake valve. Fuel lines 44 provide the fluidic communication between the fuel tank 32, the first fuel pump 34, the second fuel pump 36, and the fuel rail 40.
A controller 100 may be included in the vehicle. The controller 100 may be configured to receive signals from sensors in the vehicle as well as send command signals to components such as the first fuel pump 34 and/or the second fuel pump 36.
Various components in the vehicle 10 may be controlled at least partially by a control system including the controller 100 and by input from a vehicle operator 132 via an input device 130. In this example, input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. The controller 100 is shown in
The fuel pump 200 shown in
The fuel pump 200 includes a noise-reducing valve 204 in fluidic communication (e.g., direct fluidic communication) with the inlet 202. The noise-reducing valve 204 is configured to selectively permit and inhibit fuel flow therethrough. The noise-reducing valve 204 includes a moveable member 206, a spring 208, a first port 210, a second port 212 and a reed valve 214. In one example, the noise-reducing valve 204 may be passively controlled via hydraulic pressure in the pump.
The fuel pump 200 further includes a magnetic solenoid valve (MSV) 216. The MSV 216 is in electronic communication with a controller indicated via arrow 218, such as controller 100 shown in
The core tube 220 and the sealing element 224 move in an axial direction responsive to controller input signal. The MSV further includes a first spring 230 and a second spring 231. The neutral position of the first spring 230 and the second spring 231 may urge the core tube 220 and the sealing element in an open position, permitting fuel to flow through the MSV 216 to a pump chamber 232. On the other hand, in a closed configuration the coil 222 in the MSV 216 may be energized to urge the sealing element 224 towards the sealing surface 226. Therefore, in a closed position the sealing element 224 seats and seals in the sealing surface 226.
As shown, the noise-reducing valve 204 and the MSV 216 are shown positioned on an inlet side 234 of the fuel pump 200. Specifically, the MSV 216 is positioned downstream of the noise-reducing valve 204. However, in other examples the MSV 216 may be positioned upstream of the noise-reducing valve 204. Additionally, as depicted the MSV 216 and the noise-reducing valve 204 are in series fluidic communication. Additionally, in some examples the MSV 216 and the noise-reducing valve 204 may be in parallel fluidic communication.
The fuel pump 200 also includes the pump chamber 232 positioned downstream of the MSV and the noise-reducing valve 204. The pump chamber 232 is therefore in fluidic communication with the aforementioned valves. A plunger 236 may also be included in the fuel pump 200 and is configured to increase and decrease the volume in the pump chamber 232. The plunger 236 may be mechanically coupled to a crankshaft, cams, etc. Thus, the plunger 236 may be cam driven, in one example. Therefore, it will be appreciated that the plunger 236 may move in an upward and downward motion. The plunger 236 may be mechanically driven by an electric motor, crank shaft motion, etc. The plunger enables the pump chamber to drawn in fuel from the fuel tank and release fuel to downstream components, such as a fuel rail.
The fuel pump 200 further includes a one way discharge valve 238 positioned downstream of the pump chamber 232 and an outlet positioned downstream of the one way discharge valve 238. The one way discharge valve 238 may be in fluidic communication with a downstream fuel rail and fuel injector. The one way discharge valve is configured to permit fluid to flow through the valve in a downstream direction when the pressure of fuel in the pump chamber 232 exceeds a threshold valve and inhibit fuel flow in the downstream direction when the pump chamber pressure does not exceed the threshold value. On the other hand the one way discharge valve 238 is configured to inhibit upstream fuel flow. As shown, the one way discharge valve is a check valve including a ball 240 coupled to a spring 242. However, other suitable one way valves may be utilized in other examples.
Specifically,
Fuel is shown flowing through the first port 210 and a reed valve 214 in the noise-reducing valve 204. It will be appreciated that the reed valve 214 may act as a one way valve enabling fuel to flow in a downstream direction but inhibiting fuel to flow in an upstream direction into the first port 210. Fuel may flow from the reed valve 214 of the noise-reducing valve 204 to the MSV 216. As shown, the MSV 216 in an open configuration and the valve is deactivated. Therefore, fuel flows through the MSV into the pump chamber 232.
In
The noise-reducing valve 704 is a rotating type spool valve in the example fuel pump 700 shown in
Specifically,
At 1602 the method includes adjusting a magnetic solenoid valve (MSV) to control pump outlet pressure. Controlling pump outlet pressure may include selectively permitting an inhibiting fuel flow into a pump chamber in the fuel pump via the MSV at 1603. In one example, where the fuel is selectively permitted and inhibited to flow into the pump chamber during at least one of a delivery stroke and an intake stroke of a pump.
Next at 1604 the method includes deactivating the MSV and at 1606 the method includes controlling pump outlet pressure via a noise-reducing valve assembly on an inlet side of the fuel pump. Deactivating the MSV includes deactivating the MSV in an open position where fuel is permitted to flow therethrough. Controlling pump outlet pressure may include selectively permitting an inhibiting fuel flow into a pump chamber in the fuel pump via the noise-reducing valve at 1608 and passively controlling the noise-reducing valve via hydraulic pressure in the pump at 1610. In one example, where the fuel is selectively permitted and inhibited to flow into the pump chamber during at least one of a delivery stroke and an intake stroke of a pump.
Steps 1602 and steps 1604-1606 are implemented during different operating modes of the pump. Specifically, step 1602 may be implemented during a first mode and steps 1604 and 1606 may be implemented during a second mode. The first mode may include an operating condition when the engine is over a threshold speed and the second mode includes an operating condition when the engine is below the threshold speed, in one example. Further in other examples, the first mode may include a first engine speed range and the second mode may include a second engine speed range different from the first engine speed range. Further in one example, the first mode may include an operating condition where the fuel pump is performing a delivery stroke. The second mode may include an operating condition when the fuel pump is performing an intake stroke. It will be appreciated that the delivery stroke and the intake stroke may performed by a plunger which alters the size of a pump chamber in the pump. Further in some examples, the first mode and second mode may include engine load operating conditions (e.g., threshold values, load ranges, etc.) In the first mode a pressure in a fuel rail may be greater than a pressure in the fuel rail during the second mode. The fuel rail may be positioned downstream of the fuel pump. Additionally, it will be appreciated that the pressure in the fuel rail during the second mode is greater than a pressure in a fuel line upstream of the pump.
The method includes at 1702 when the engine is above a threshold speed, adjusting a magnetic solenoid valve (MSV) to control pump outlet pressure. The threshold speed may be associated with idle operation, in one example. Therefore, the engine may be in idle operation when the engine speed is below the threshold value. Idle operation may be an engine operating mode where there is no request for vehicle acceleration, from a pedal for example. Therefore, the pedal may be released during idle operation. Additionally, the engine may be maintained at a desired speed during idle.
The method includes when the engine is below the threshold speed, deactivating the MSV at 1704 and controlling an inflow and outflow of a pump chamber via a noise-reducing valve assembly on an inlet side of the fuel pump at 1706. In one example, when the engine is below the threshold speed the deactivated MSV is deactivated in an open position during an intake stroke of the fuel pump. Controlling the inflow and outflow of the pump chamber via the noise-reducing valve includes configuring the noise-reducing valve to enable fuel to flow therethrough during an intake stroke of the pump at 1708 and substantially inhibit fuel to flow therethrough during a delivery stroke at 1710. It will be appreciated that steps 1704 and 1706 may be implemented during a cold start when the engine is below a threshold temperature.
Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the engine control system.
It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to V-6, 1-4, 1-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.
