GB2567011A

GB2567011A - Fuel injection system for engine system

Info

Publication number: GB2567011A
Application number: GB1716048.2A
Authority: GB
Inventors: Joachim Sixel Eike; Sturm Michael
Original assignee: Caterpillar Motoren GmbH and Co KG
Current assignee: Caterpillar Motoren GmbH and Co KG
Priority date: 2017-10-02
Filing date: 2017-10-02
Publication date: 2019-04-03
Anticipated expiration: 2037-10-02
Also published as: GB2567011B; GB201716048D0

Abstract

A fuel injection system 110 for an engine system 100 is disclosed. The system comprises a fuel pump 112 and nozzle 114 for each cylinder 104 of the engine 102. A control valve 212 is biased, for example by a spring, in a normally open position and is actuated against this to prevent fuel flowing from the pump to the injector 114. A drainage valve 214 is biased in a normally closed position and is actuated against this to allow fuel to flow from the pump and bypass the nozzle. During operation fuel enters the cylinder when the control valve is open and the drain valve is closed. The system allows fuel multiple fuel injections and changes in fuel injection timing whilst still allowing fuel to be injected in the event of valve failure. A method of operating as fuel injection system in one of two modes is also disclosed. During normal operation timing of fuel supply is controlled by a control valve. IN a failure mode the control valve remains open and the fuel pump is controlled to vary the metering of the fuel.

Description

Technical Field [0001] The present disclosure relates to an engine system. More particularly, the present disclosure relates to a fuel injection system for the engine system.

Background [0002] Internal combustion engines such as diesel engines may include conventional pump-line-nozzle fuel injection systems for delivering fuel to one or more cylinders of the engines. The pump-line-nozzle fuel injection systems generally include one fuel pump and one fuel injector for each cylinder. The fuel pump is generally a reciprocating pump that is actuated by an associated cam to pump the fuel to the fuel injector and thereby to an associated cylinder. Further, the fuel injector is a spring biased pressure actuated valve, allowing an injection of the fuel from the fuel injector into the cylinder when a fuel pressure inside the fuel injector exceeds spring biasing force. However, it is generally neither possible to achieve change in a timing of a main fuel injection to the cylinder nor possible to achieve multiple fuel injections, such as a pre-fuel injection or a post fuel injection along with a main fuel injection.

[0003] US Patent No. 6,796,290 (’290 patent) relates to a fuel injection system for an engine having one fuel pump and one fuel injection valve for each cylinder of the engine. The fuel injection valve includes a valve member, and a pressure chamber and a control pressure chamber disposed on the opposite sides of the valve member. The valve member is spring biased in a closed position to prevent injection of the fuel into a cylinder. Further, the fuel injection system includes an electrically actuating blocking valve that is spring biased in an open position to allow a flow of fuel to both the pressure chamber and the control pressure chamber.

10 17

Also, the fuel injection system includes a second electrically actuated control valve that is spring biased in a closed position to prevent a flow of fuel from the control pressure chamber to the relief chamber. To allow an injection of the fuel into the cylinder, a pressure of fuel in the control pressure chamber is reduced by electrically actuating the second control valve to an open position. Although the fuel injection system disclosed in the ’290 patent may allow multiple fuel injections and change in fuel injection timing, the fuel injection system does not allow an injection of fuel into the cylinder upon an occurrence of electrical failure, and therefore interrupts an operation of the engine.

Summary of the Invention [0004] In one aspect, the disclosure relates to a fuel injection system for an engine system. The engine system includes an engine having one or more cylinders. The fuel injection system includes one fuel pump and one nozzle, communicating with the fuel pump, for each cylinder of at least a subset of the cylinders of the engine. The fuel injection system further includes a control valve and a drain valve. The control valve is configured to control a connection of the nozzle with the fuel pump. The control valve is actuable, counter to an opening force, preventing in a closed position a flow of fuel from the fuel pump to the nozzle. The drain valve is configured to control a flow of fuel from the fuel pump to bypass the nozzle. The drain valve is actuable, counter to a closing force, allowing in an open position the flow of fuel from the fuel pump to bypass the nozzle. Fuel is injected into the cylinder of the engine when the control valve is in an open position and the drain valve is in a closed position. The drain vale is a valve to close or open the drain port whereas the pressure control valve will keep the fuel pressure in the reservoir at or below a desired value.

[0005] In another aspect, the disclosure relates to an engine system. The engine system includes an engine an engine having one or more cylinders, one fuel pump and one nozzle, communicating with the fuel pump, for each cylinder of at least a

10 17 subset of the cylinders of the engine, a control valve, a drain valve, and a controller. The control valve is configured to control a connection of the nozzle with the fuel pump. The control valve is actuable, counter to an opening force, preventing in a closed position a flow of fuel from the fuel pump to the nozzle. Further, the drain valve is configured to control a flow of fuel from the fuel pump to bypass the nozzle. The drain valve is actuable, counter to a closing force, allowing in an open position the flow of fuel from the fuel pump to bypass the nozzle. Furthermore, the controller is configured for controlling closing of the control valve. The fuel is injected into the cylinder of the engine when the control valve is in an open position and the drain valve is in a closed position.

[0006] In yet another aspect, the disclosure relates to a method of operating a fuel injection system for an engine system. The engine system includes an engine having one or more cylinders. The fuel injection system includes one fuel pump and one nozzle, communicating with the fuel pump, for each cylinder of at least a subset of the cylinders. The method includes controlling closing of a control valve to vary an injection timing of fuel supply to the engine in a normal mode of operation. The control valve is actuable, counter to an opening force, in a closed position for preventing a flow of fuel from the fuel pump to the nozzle. The method further includes controlling the fuel pump to vary fuel supply to the engine in a failure mode of operation. In the failure mode, the control valve remains open due to the opening force to facilitate flow of fuel to the nozzle.

Brief Description of the Drawings [0007] FIG. 1 is a diagrammatic view of an engine system having a fuel injection system, in accordance with an aspect of the present disclosure;

[0008] FIG. 2 is a diagrammatic view of a fuel pump of the fuel injection system depicting a vertical distance between a second port of the fuel pump and a portion of a drain passage directly below the second port, in accordance with an aspect of the present disclosure;

10 17 [0009] FIG. 3 is a diagrammatic view of the fuel pump of the fuel injection system depicting a vertical distance between the second port of the fuel pump and a portion of the drain passage directly below the second port, in accordance with an aspect of the present disclosure;

[0010] FIG. 4 is a diagrammatic view of the fuel pump of the fuel injection system depicting a vertical distance between the second port of the fuel pump and a portion of the drain passage directly below the second port, in accordance with an aspect of the present disclosure;

[0011] FIG. 5 is a diagrammatic view of an engine system having a fuel injection system, in accordance with an alternative aspect of the present disclosure; and [0012] FIG. 6 is a diagrammatic view of an engine system having a fuel injection system, in accordance with yet another alternative aspect of the present disclosure.

Detailed Description [0013] Referring to FIG. 1, an engine system 100 is illustrated. The engine system 100 may be applied in machines, such as those that are applicable in a marine industry, a construction industry, a mining industry, an agricultural industry, a transport industry, etc. In some implementations, the engine system 100 may be applied in stationary power generating machines, and to machines that are applied in commercial and domestic environments.

[0014] The engine system 100 includes an engine 102 having one or more cylinders 104 (only one depicted in FIG. 1), and a fuel injection system 110 having one fuel pump 112 and one nozzle 114, communicating with the fuel pump 112, for each cylinder 104 of at least a subset of the cylinders 104 of the engine 102. The nozzle 114 is configured to provide fuel into an associated cylinder 104 of the engine 102. In an embodiment, the fuel pump 112 is a reciprocating pump 112a. The engine 102 may also include a cylinder head 116 coupled to a first end of the

10 17 cylinders 104, and a crankcase (not shown) coupled to a second end of the cylinders 104. The cylinder head 116 may act as a support structure for mounting various other components of the engine 102 such as an intake valve 118, an exhaust valve 120, the nozzle 114, etc. The cylinder head 116 may include various features such as an intake conduit 122 for allowing intake of air/exhaust gases into a combustion chamber 124, and an exhaust conduit 126 for facilitating discharge of exhaust gases from the combustion chamber 124.

[0015] Each cylinder 104 is defined by a cylinder bore 130 formed in an engine block 132. The engine 102 further includes one or more pistons 134 (only one shown) with one piston 134 associated with one cylinder 104. The piston 134 is disposed within the cylinder bore 130, and is configured to reciprocate within the cylinder bore 130 between a top dead center (TDC) and a bottom dead center (BDC). The piston 134 includes a piston crown 136 that faces a flame deck surface 138 of the cylinder head 116. The piston 134 may further include other structural features, such as a piston bowl to facilitate combustion of a fuel, a plurality of grooves to receive a plurality of piston rings, etc. The piston 134 is coupled to a connecting rod 150 that is in turn rotatable coupled to a crankshaft 152 of the engine 102. A reciprocal movement of the piston 134 translates into a rotary movement of the crankshaft 152. The crankshaft 152 is operatively coupled to a camshaft 156 of the engine 102 such that a rotary movement of the crankshaft 152 translates into a rotary movement of the camshaft 156. The camshaft 156 may be operatively coupled to the crankshaft 152 via a gear assembly, a belt-pully assembly, or any other similar mechanism known in the art.

[0016] A rotation/movement of the camshaft 156 facilitates an operation of the fuel pump 112, facilitating, and regulating in some cases, a fuel delivery into the combustion chamber 124, and hence into the cylinder 104 for combustion. To this end, a fuel cam 160 of the engine 102 is mounted on the camshaft 156 to operate the fuel pump 112. As the camshaft 156 is rotated, a lobe portion 162 of the fuel cam 160 pushes a plunger 164 of the fuel pump 112 to initiate a delivery of fuel from the fuel pump 112 to the combustion chamber 124 of the cylinder 104.

10 17

Therefore, the fuel pump 112 is actuated by the fuel cam 160 to pump fuel. A cam follower 166 may be disposed between the plunger 164 and the fuel cam 160, and contacts the fuel cam 160. As the fuel cam 160 rotates, the cam follower 166 may follow a profile of the fuel cam 160 to cause a movement of the plunger 164. Although a single cylinder is shown, the engine 102 may include multiple cylinders, and thus a configuration and working of the single cylinder, as shown, may be applicable to engines that use multiple cylinders, as well.

[0017] Referring to FIG. 1, the fuel pump 112 may include a cylindrical body 170 having a cylindrical wall 172 defining a bore 174 along a longitudinal axis 176 of the cylindrical body 170, and the plunger 164 slidable disposed within the bore 174. The plunger 164 may be configured to reciprocated within the cylindrical body 170 to cause a pumping of fuel by the fuel pump 112. Further, the cylindrical body 170 and hence the fuel pump 112 includes a plurality of ports, for example, a first port 178 and a second port 180 extending in a radial direction relative to the longitudinal axis 176. The first port 178 and the second port 180 may facilitate ingress of fuel into the bore 174, and hence into the cylindrical body 170, and may facilitate egress of fuel out of the cylindrical body 170. The first port 178 and second port 180 extend through an entire thickness of the cylindrical wall 172, and may be aligned with each other. The plunger 164 may be biased in a downward position by a biasing member such as a spring. The plunger 164 is configured to move in an upward direction when pushed by the cam follower 166 when the cam follower 166 contacts the lobe portion 162 of the fuel cam 160.

[0018] The plunger 164 may include a drain passage 184 spirally formed at an outer periphery 186 of the plunger 164. The drain passage 184 may extend from a first end 188 of the plunger 164, and spiral towards a second end 190 of plunger 164. An end of the drain passage 184 disposed at the first end 188 of the plunger 164 defines an inlet opening 192 at an axial end face 194 of the plunger 164, while another end of the drain passage 184 may be disposed at a distance from the second end 190 of the plunger 164. The plunger 164 is configured to rotate within the cylindrical body 170 to control/vary a timing of a drain/outlet of fuel from the bore

10 17

174, and thus from the cylindrical body 170 through one of the plurality of ports, for example, the second port 180. A rotation of the plunger 164 within the bore 174 may cause a change in a vertical distance between the second port 180 and a portion of the drain passage 184 disposed directly below the second port 180. The vertical distance corresponds to a distance when the plunger 164 is at a retracted position (i.e. at a lowest position within the cylindrical body 170). Therefore, the plunger 164 may be rotated to vary a timing of a connection between the drain passage 184 and one of the plurality of ports, such as the second port 180, to vary an amount of fuel pumped by the fuel pump 112.

[0019] FIG. 2 discloses a rotational position of the plunger 164 within the cylindrical body 170 in which the vertical distance between the second port 180 and a portion of the drain passage 184 disposed directly below the second port 180 is ‘dl’. FIG. 3 discloses a rotational position of the plunger 164 within the cylindrical body 170 in which the vertical distance between the second port 180 and a portion of the drain passage 184 disposed directly below the second port 180 is ‘d2’. FIG. 4 discloses a rotational position of the plunger 164 within the cylindrical body 170 in which the vertical distance between the second port 180 and a portion of the drain passage 184 disposed directly below the second port 180 is ‘d3’.

[0020] The nozzle 114 is mounted to the cylinder head 116 such that a tip portion ofthe nozzle 114 may extend into the combustion chamber 124 ofthe cylinder 104. The nozzle 114 is configured to inject fuel into the cylinder 104. As shown, the nozzle 114 may include a body 198 defining a longitudinal cavity 200, and one or more orifices 202 formed within the body 198. The one or more orifices 202 are in fluid communication with the longitudinal cavity 200, and are configured to inject fuel into the cylinder 104. In an embodiment, the nozzle 114 may include a valve member 204 disposed within the longitudinal cavity 200, and a spring 206 engaged with the valve member 204 for biasing the valve member 204 in a closed position. In the closed position, the valve member 204 closes the one or more orifices 202 of the nozzle 114 to prevent a flow of fuel from the nozzle 114 to the 7

10 17 combustion chamber 124 of the cylinder 104. The valve member 204 may be configured to move to an open position in response to a pressure of fuel acting on the valve member 204 to inject of fuel within the cylinder 104 through the one or more orifices 202. In an alternate embodiment, the valve member 204 and the spring 206 may be omitted.

[0021] Again referring to FIG. 1, the fuel injection system 110 may be a pumpline-nozzle system 208, may include one reservoir 210, one control valve 212, and one drain valve 214 for each cylinder 104 of the engine 102. The reservoir 210 may be fluidly coupled to the fuel pump 112 and the nozzle 114. The reservoir 210 is configured to receive fuel pumped by the fuel pump 112, and is configured to provide fuel to the nozzle 114 for injecting fuel into the cylinder 104 for combustion. In certain implementations, the reservoir 210 may be an accumulator, and store fuel received from the fuel pump 112 at a pressure. The reservoir 210 may receive fuel from the fuel pump 112 via a main conduit 218. Thus, the main conduit 218 fluidly couples the fuel pump 112 to the reservoir 210. The reservoir 210 may include a drain port 220 to facilitate a drainage or return of fuel from the reservoir 210 to a fuel tank (not shown). Further, to enable a flow of fuel to the nozzle 114, the reservoir 210 may include an outlet port 222 in fluid communication with the nozzle 114.

[0022] Control valve 212 is configured to control the flow of fuel from the reservoir 210 to the nozzle 114. Thus, the control valve 212 is configured to control a connection of the nozzle 114 with the fuel pump 112 to control a timing and flow of fuel to the nozzle 114 and the cylinder 104. The control valve 212 may be connected with the reservoir 210 via a first conduit 226, and may be connected with the nozzle 114 via a second conduit 228. The first conduit 226 is coupled to the outlet port 222 of the reservoir 210. The control valve 212 is configured to move between an open position and a closed position. In the open position, the control valve 212 allows a flow of fuel to the nozzle 114, while in the closed position, the control valve 212 prevents a flow of fuel to the nozzle 114. The control valve 212 is biased in the open position by an opening force that may be 8

10 17 provided by a biasing member 230. In an embodiment, the control valve 212 may include a spring 232 as the biasing member 230 to provide the opening force/biasing force to keep/bias the control valve 212 in the open position in absence of any external signal/force. Alternatively, the control valve 212 may include a magnet or other similar arrangement as the biasing member 230 to provide the opening force/biasing force, and thus bias the control valve 212 in the open position. It may be appreciated the opening force is not provided by any energy source external to the control valve 212.

[0023] To move the control valve 212, counterto the opening force, to the closed position, an external actuation of the control valve 212 is required. Therefore, the control valve 212 is actuable, counter to the opening force, to the closed position for preventing a flow of fuel from the fuel pump 112 to the nozzle 114. In an embodiment, the control valve 212 may be an electrically actuated valve for moving the control valve 212 to the closed position. In such a case, the control valve 212 may be solenoid operated valve. In certain other implementations, the control valve 212 may be a hydraulically actuated valve for moving the control valve 212 to the closed position.

[0024] The drain valve 214 is configured to control a flow of fuel from the fuel pump 112 to bypass the nozzle 114. As shown in FIG. 1, the drain valve 214 is configured to control a drain of fuel from the reservoir 210 through the drain port 220. The drain valve 214 may be connected with the drain port 220 of the reservoir 210 via a drain conduit 236. Similar to the control valve 212, the drain valve 214 is configured to move between an open position and a closed position. In the open position, the drain valve 214 facilitates a fuel received from the fuel pump 112 to bypass the nozzle 114. In an embodiment, the drain valve 214, in the open position, allows a flow of fuel out of the reservoir 210, thereby facilitating a fuel received from the fuel pump 112 to bypass the nozzle 114. In the closed position, the drain valve 214 prevents the drain of fuel from the reservoir 210, thereby preventing the fuel received from the fuel pump 112 to bypass the nozzle 114. The drain valve 214 is biased in the closed position by a closing force to prevent the flow of fuel

10 17 from the fuel pump 112 to bypass the nozzle 114. In an embodiment, the drain valve 214 includes a spring 240 that provides the closing force to keep/bias the drain valve 214 in the closed position in absence of any external signal/force. Alternatively, the drain valve 214 may include a magnet or other similar arrangement to provide the closing force, and thus bias the drain valve 214 in the closed position. It may be appreciated that the closing force is not provided by any energy source external to the drain valve 214.

[0025] To move the drain valve 214, counter to the closing force, to the open position, an external actuation of the drain valve 214 is required. Therefore, the drain valve 214 is actuable, counter to the closing force, to the open position for preventing a flow of fuel from the fuel pump 112 to bypass the nozzle 114. In an embodiment, the drain valve 214 may an electrically actuated valve for moving the drain valve 214 to the open position. In such a case, the drain valve 214 may be a solenoid operated valve. In certain other implementations, the drain valve 214 may be a hydraulically actuated valve for moving the drain valve 214 to the open position.

[0026] The fuel injection system 110 may further include a controller 250 for controlling an operation of the control valve 212 and the drain valve 214. In an embodiment, the controller 250 is configured to control closing of the control valve 212. In another embodiment, the controller 250 is also configured to control opening of the drain valve 214. The controller 250 may be configured to monitor one or more parameters of the engine 102, and control both the control valve 212 and the drain valve 214 to inject fuel into the cylinder 104 of the engine 102. In certain implementations, the controller 250 may enable multiple fuel injection events and/or enable changes in injection timings of fuel from the nozzle 114 into the cylinder 104 during an engine cycle based on one or more engine parameters. The change in injection timing may refer to a change in timing of a start of the injection of fuel or a change in a duration of injection of fuel or a combination thereof. In some implementations, the controller 250 may control both the control valve 212 and the drain valve 214 to effect multiple fuel injection events, for 10

10 17 example a main fuel injection event along with a pre-fuel injection event and/or or a post fuel injection event. Alternatively, the controller 250 may control both the control valve 212 and the drain valve 214 to change an injection timing of the main fuel injection event along with effecting the pre-fuel injection event and/or or the post fuel injection event. The one or more engine parameters may include an engine load, an engine speed, an engine power, etc.

[0027] Referring to FIG. 5, an engine system 100’ having a fuel injection system 110’ is shown according to an alternative embodiment of the disclosure. The fuel injection system 110’ may be a pump-line-nozzle system 208’. In this embodiment, the reservoir 210 and the first conduit 226 is omitted. In such a case, the control valve 212 is connected to the main conduit 218 to receive fuel from the fuel pump 112. Further, the control valve 212 is connected to the nozzle 114 via the second conduit 228 to provide fuel to the nozzle 114. Also, the drain valve 214 is connected with the main conduit 218 via the drain conduit 236. The drain conduit 236 is coupled to the main conduit 218 at a location upstream of the control valve 212. The drain valve 214 controls a flow of fuel received from the fuel pump 112 to bypass the nozzle 114 via the drain conduit 236 to the fuel tank (not shown). Further, functioning and structure of all the other elements of the fuel injection system 110’ and thus the engine system 100 ’ is similar to the function and structure of corresponding elements of the fuel injection system 110 and the engine system

100.

[0028] Referring to FIG. 6, an engine system 100” having a fuel inj ection system 110” is shown according to an alternative embodiment of the disclosure. The fuel injection system 110” may be a pump-line-nozzle system 208”. In this embodiment, the drain valve 214 is apressure actuated valve 214a. In such a case, the drain valve 214 (the pressure actuated valve 214a) is actuated by a pressure of the fuel within the reservoir 210. The drain valve 214 (the pressure actuated valve 214a) is moved to the open position in response to the pressure in the reservoir 210 exceeding a predefined pressure. Therefore, the drain valve 214 (the pressure actuated valve 214a) facilitates a drain of fuel from the reservoir 210 when the

10 17 pressure of fuel in the reservoir 210 exceeds the predefined pressure. Thus, the pressure actuated valve 214a functions as a relief valve for the reservoir 210. With the exception of the drain valve 214 being the pressure actuated valve 214a, all other elements of the fuel injection system 110” and the engine system 100” is similar to corresponding elements of the fuel injection system 110 and the engine system 100.

Industrial Applicability [0029] An exemplary operation of the engine system 100, 100’, 100” having the fuel injection system 110, 110’, 110” is explained. During operation, the controller 250 may monitor the one or more engine parameters, for example the engine load, or engine speed, or a combination thereof. Based on the one or more engine parameters, a fuel requirement for the cylinder 104 of the engine 102 is determined. In an embodiment, the controller 250 may determine the fuel requirement for the cylinder 104 of the engine 102 based on the engine load, and control the fuel pump 112 to pump the fuel based on the determined fuel requirement. Alternatively, the fuel pump 112 may be connected to a speed governor which in turn controls the fuel pump 112. The speed governor may control the fuel pump 112 based on the one or more engine parameters, for example engine speed, engine load, etc. In an embodiment, the speed governor may control a rotation of the plunger 164 of the fuel pump 112 to vary an amount of fuel injected into the cylinder 104 and thus the engine 102. In an exemplary embodiment, during a low engine load, for example during engine idling, the plunger 164 of the fuel pump 112 may be rotated to decrease the vertical distance between the second port 180 and the portion of the drain passage 184 disposed directly below the second port 180. For example, the plunger 164 may be rotated to the rotational position shown in FIG. 4. Due to such positioning of the plunger 164, during a pumping stroke of the fuel pump 112, the drain passage 184 may get fluidly connected to the second port 180 relatively earlier allowing a drain of relatively large amount of

10 17 fuel from the bore 174, thereby causing a pumping of a smaller amount of fuel out of the fuel pump 112 and reducing the mechanical losses of the engine 102.

[0030] During a higher engine loads, a relatively large amount of fuel is needed to be injected into the cylinder 104. To enable such an injection, the plunger 164 may be rotated to increase the vertical distance between the second port 180 and the portion of the drain passage 184 directly below the second port 180. For example, the plunger 164 may be rotated to the rotational position shown in FIG.

2.

[0031] Referring to FIG. 1 and FIG. 5, to inject fuel, during a normal mode of operation of the fuel injection system 110, 110’, into the cylinder 104 (the engine 102) at a certain injection timing, the controller 250 may initially actuate the control valve 212 to the closed position and the drain valve 214 to the open position. This causes a drain of the fuel pumped by the fuel pump 112 to the fuel tank via the drain conduit 236 during the pumping stroke of the fuel pump 112. In an embodiment, as shown in FIG. 1, the controller 250 may only actuate/move the control valve 212 to the closed position to facilitate a rise in the pressure of fuel within the reservoir 210. The controller 250 may actuate the drain valve 214 to the open position when the pressure of fuel within the reservoir 210 exceeds a predetermined pressure. To enable a fuel injection at a certain injection timing, determined by the controller 250, the controller 250 disables the actuation of both the control valve 212 and the drain valve 214. Disabling of the actuation of the control valve 212 and the drain valve 214 causes the control valve 212 and the drain valve 214 to move to the open position and the closed position, respectively. In this manner, the fuel pumped by the fuel pump 112 is injected to the combustion chamber 124 via the nozzle 114 at the injection timing determined by the controller 250. Further, the controller 250 may again actuate the control valve 212 to the closed position and the drain valve 214 to the open position after a predetermined duration. This causes the fuel received from the fuel pump 112 to drain via the drain conduit 23, thereby stopping the injection of fuel into the cylinder 104. In this manner, a duration of the fuel injection event, and hence amount of fuel 13

10 17 injected to the cylinder 104 may also be controlled. To vary the injection timing, and hence a start of injection, or an end of injection, or an amount of fuel injected to the cylinder 104, or a combination thereof, the controller 250 may control the timing of the closing and opening of the control valve 212 and the drain valve 214. [0032] To effect multiple fuel injection events during an engine cycle, the controller 250 may actuate and de-actuate the control valve 212 and drain valve 214 multiple times during a single engine cycle. For example, the controller 250 may disable actuation of the control valve 212 and the drain valve 214 to cause a first fuel injection event, for example a main injection event. After, certain duration, the controller 250 may actuate the control valve 212 to the closed position and may actuate the drain valve 214 to the open position to disable a fuel flow into the combustion chamber 124 or cylinder 104, and thereby ending the first fuel injection event. Further, the controller 250, during the same pumping stroke of the fuel pump 112, may again disable actuation of the control valve 212 and the drain valve 214 to cause a fuel flow into the cylinder 104 and thereby ensuring a second fuel injection event, for example a post fuel injection event. The controller 250 may determine a start timing and a duration of one or more fuel injection events based on the one or more engine parameters. Thus, the fuel injection system 110, 110’ allows for change in injection timing as well as allows multiple fuel injections during a single engine cycle. This helps in improving an efficiency of the engine system 100, 100’.

[0033] Referring to FIG. 6, to inject fuel during a normal mode of operation of the fuel injection system 110”, into the cylinder 104 (the engine 102), the controller 250 may initially actuate the control valve 212 to the closed position. This may cause a rise in the pressure of fuel within the reservoir 210. As the drain valve 214 (the pressure actuated valve 214a) is actuated by the pressure of fuel within the reservoir 210, the drain valve 214 (the pressure actuated valve 214a) may move to the open position, counter to the closing force, when the pressure of fuel within the reservoir 210 exceeds the predefined pressure. The predefined pressure may be sufficient to overcome the closing force of the drain valve 214

10 17 (the pressure actuated valve 214a) to move the drain valve 214 (the pressure actuated valve 214a) in the open position.

[0034] To enable a fuel injection at a certain injection timing, determined by the controller 250, the controller 250 disables the actuation of the control valve 212. Disabling of the actuation of the control valve 212 to move to the open position. In this manner, the fuel pumped by the fuel pump 112 is injected to the combustion chamber 124 via the nozzle 114 at the injection timing determined by the controller 250. Further, the controller 250 may again actuate the control valve 212 to the closed position after a predetermined duration, thereby stopping the injection of fuel into the cylinder 104 (the engine 102). In this manner, by controlling the closing of the control valve 212, an injection timing of the fuel injection event, and hence a start of injection, or an end of injection, or an amount of fuel injected to the cylinder 104, or a combination thereof, may be controlled.

[0035] To effect multiple fuel injection events during an engine cycle, the controller 250 may actuate and de-actuate the control valve 212 multiple times during a single engine cycle. For example, the controller 250 may disable an actuation of the control valve 212 to cause a first fuel injection event, for example a main injection event. After, certain duration, the controller 250 may actuate the control valve 212 to the closed position to disable a fuel flow into the combustion chamber 124 or cylinder 104 (the engine 102), and thereby ending the first fuel injection event. Further, the controller 250, during the same pumping stroke of the fuel pump 112, may again disable actuation of the control valve 212 to cause a fuel flow into the cylinder 104 (the engine 102) and thereby ensuring a second fuel injection event, for example a post fuel injection event. The controller 250 may determine a timing and a duration of one or more fuel injection events based on the one or more engine parameters. Thus, the fuel injection system 110” allows for change in injection timing as well as allows multiple fuel injections during a single engine cycle. This helps in improving an efficiency of the engine system 100”.

[0036] Further, as the control valve 212 and the drain valve 214 are biased in the open position and the closed position, the control valve 212 and the drain valve 15

10 17

214 remains open and closed respectively in an absence of any external actuations, such as actuations by the controller 250. This enables injection of fuel from the fuel pump 112 into the cylinder 104 even when a failure i.e. during a failure mode of operation, for example a loss of electric power supply, occurs. This ensure a continued operation of the fuel injection system 110, 110’, 110” of the engine system 100, 100’, 100” even in the event of an electrical failure. During the failure mode of operation, the fuel pump 112 is controlled to vary fuel supply to the cylinder 104 (the engine 102). In the failure mode of operation, the engine 102 may be operated in the full load range with an increased fuel consumption. In such a case, in certain implementations, the speed governor may control the fuel pump 112 to control the fuel injection timing and the duration of fuel supply to the cylinder 104 (the engine 102). In an embodiment, the injection timing i.e. a start of fuel injection into the cylinder 104 (the engine 102) is defined by the increasing fuel pressure from the fuel pump 112. An end of fuel injection may be controlled by varying a timing of drain of fuel from the fuel pump 112 during the pumping stroke of the fuel pump 112 by the rotation of the plunger 164 as described earlier.

Claims

Claims 17 10 17 What is claimed is:

1. Afuel injection system (110, 110’, 110”) for an engine system (100, 100’, 100”), the engine system (100, 100’, 100”) including an engine (102) having one or more cylinders (104), the fuel injection system (110, 110’, 110”) comprising:

one fuel pump (112) and one nozzle (114), communicating with the fuel pump (112), for each cylinder (104) of at least a subset of the cylinders (104) of the engine (102);

a control valve (212) configured to control a connection of the nozzle (114) with the fuel pump (112), the control valve (212) being actuable, counter to an opening force, preventing in a closed position a flow of fuel from the fuel pump (112) to the nozzle (114); and a drain valve (214) configured to control a flow of fuel from the fuel pump (112) to bypass the nozzle (114), the drain valve (214) being actuable, counter to a closing force, allowing in an open position the flow of fuel from the fuel pump (112) to bypass the nozzle (114), wherein fuel is being injected into the cylinder (104) of the engine (102)whenthe control valve (212) is in an open position and the drain valve (214) is in a closed position.

2. The fuel injection system (110, 110’, 110”) of claim 1 further including a controller (250) for controlling closing of the control valve (212).

3. The fuel injection system (110, 110’, 110”) of claim 1, wherein the fuel pump (112) is a reciprocating pump (112a) configured to be actuated by a fuel cam (160) of the engine (102).

17 10 17

4. The fuel injection system (110, 110’, 110”) of claim 1, wherein the fuel injection system (110, 110’, 110”) is a pump-line-nozzle system (208, 208’, 208”).

5. The fuel injection system (110, 110’, 110”)of claim 1, wherein the control valve (212) includes a spring (232) configured to provide the opening force to bias the control valve (212) in the open position.

6. The fuel injection system (110, 110’, 110”) of claim 1, wherein the drain valve (214) includes a spring (240) configured to provide the closing force to bias the drain valve (214) in the closed position.

7. The fuel injection system (110, 110’, 110”) of claim 1 further including a reservoir (210) fluidly coupled to the fuel pump (112) and the nozzle (114), wherein the reservoir (210) is configured to receive fuel from the fuel pump (112) and to provide fuel to the nozzle (114).

8. The fuel injection system (110, 110’, 110”) of claim 7, wherein the drain valve (214) is a pressure actuated valve (214a) coupled to the reservoir (210), and is movable to the open position in response to a pressure in the reservoir (210) exceeding a predefined pressure.

9. The fuel injection system (110, 110’, 110”) of claim 1, wherein the fuel pump (112) includes a cylindrical body (170) having a plurality of ports to allow ingress of fuel into the cylindrical body (170) and egress of fuel out of the cylindrical body (170); and a plunger (164) configured to reciprocate within the cylindrical body (170), the plunger (164) includes a drain passage (184) spirally formed at an outer periphery (186) of the plunger (164), wherein the plunger (164) is rotated to vary a timing of a connection between the drain

17 10 17 passage (184) and one of the plurality of ports to vary an amount of fuel pumped by the fuel pump (112).

10. A method of operating a fuel injection system (110, 110’, 110”) for an engine system (100, 100’, 100”), the engine system (100, 100’, 100”) includes an engine (102) having one or more cylinders (104), the fuel injection system (110, 110’, 110”) including one fuel pump (112) and one nozzle (114), communicating with the fuel pump (112), for each cylinder (104) of at least a subset of the cylinders (104), the method comprising: controlling closing of a control valve (212) to vary an injection timing of fuel supply to the engine (102) in a normal mode of operation, wherein the control valve (212) is actuable, counter to an opening force, in a closed position for preventing a flow of fuel from the fuel pump (112) to the nozzle (114); and controlling the fuel pump (112) to vary fuel supply to the engine (102) in a failure mode of operation, wherein in the failure mode of operation, the control valve (212) remains open due to the opening force to facilitate a flow of fuel to the nozzle (114).