Patent Application
20140156169
The present disclosure relates to a control system for a multi-cylinder engine, and more particularly to a control system for fuel delivery systems associated with cylinders of the multi-cylinder engine.
Conventional fuel changeover systems for engines may allow a change in fuel type input to the engine. However, in specific cases, when transitioning from a compression ignited fuel, such as diesel, to a spark ignited fuel, such as gasoline or natural gas, residual by-products resulting from the combustion of the compression ignited fuel may be left behind in a cylinder of the engine. Typically, pre-ignition characteristics of spark ignited fuels may be different from that of compression ignited fuels. The residual by-products left behind in the cylinder of the engine may cause detrimental effects such as knocking, or detonation from pre-ignition of the spark ignited fuel. Thus, the residual by-products may negatively impact transitioning from the compression ignited fuels to the spark ignited fuels within the engine and deteriorate engine performance.
PCT Application 2011/098077 relates to a method for switching the fuel supply to an internal combustion engine from a first fuel to a second fuel. The method comprises the steps of operating the internal combustion engine using the first fuel, lowering the fraction of the first fuel in the fuel line supplying first fuel to the internal combustion engine and increasing the fraction of the second fuel in the fuel line supplying second fuel to the internal combustion engine, operating the internal combustion engine using a fuel mixture comprising the first fuel and the second fuel, and repeating the preceding steps until the internal combustion engine is operated only using the second fuel.
In one aspect, the present disclosure provides a control system for fuel delivery systems associated with cylinders of a multi-cylinder engine. The control system includes a detector, a processor, and an actuator. The detector is configured to sense a signal to change from a compression ignited fuel to a spark ignited fuel in a pre-determined number of cylinders. The processor is configured to receive the signal from the detector and generate one or more actuation signals. The controller is configured to receive the actuation signals and tandemly control the fuel delivery systems associated with the pre-determined cylinders based on the actuation signals.
In another aspect, the present disclosure provides a power system including the multi-cylinder engine, multiple fuel delivery systems, and the control system. The fuel delivery systems are associated with the cylinders of the multi-cylinder engine and configured to deliver at least one of a compression ignited fuel and a spark ignited fuel. The control system is operatively connected to the fuel delivery systems and includes the detector, the processor, and the controller. The detector is configured to sense a signal to change from the compression ignited fuel to the spark ignited fuel in a pre-determined number of cylinders. The processor is configured to receive the signal from the detector and generate one or more actuation signals. The controller is configured to receive the actuation signals and tandemly control the fuel delivery systems associated with the pre-determined cylinders based on the actuation signals.
In another aspect, the present disclosure provides a method of changing a fuel type in a multi-cylinder engine. The method includes allowing delivery of a compression ignited fuel into cylinders of the engine. The method further includes pre-determining a number of cylinders. The method further includes sensing a signal to change from the compression ignited fuel to the spark ignited fuel in the pre-determined cylinders. The method further includes processing the signal to generate one or more actuation signals. The method further includes tandemly controlling the fuel delivery systems associated with the pre-determined cylinders based on the actuation signals.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
The present disclosure relates to a control system for fuel delivery systems associated with cylinders of a multi-cylinder engine.
In an embodiment, the multi-cylinder engine 102 may be configured to operate on varying thermodynamic cycles. In one embodiment, the multi-cylinder engine 102 may be configured to operate on a diesel combustion cycle. Accordingly, the multi-cylinder engine 102 may use any compression ignited fuel that is compatible with the diesel combustion cycle, for example, diesel. In another embodiment, the multi-cylinder engine 102 may be configured to operate on an Otto cycle. Therefore, in this embodiment, the multi-cylinder engine 102 may use any spark ignited fuel compatible with the Otto cycle, for example, gasoline, natural gas, synthesis gas (syngas).
The power system 100 further includes multiple fuel delivery systems 104 associated with cylinders 106, 108, 110, and 112 of the multi-cylinder engine 102. The fuel delivery system 104 is configured to selectively deliver at least one of the compression ignited fuel and the spark ignited fuel. In an embodiment the power system 100 may further include one or more ignition sources 114 associated with each of the cylinders 106, 108, 110, and 112. The ignition sources 114 may be configured to ignite the spark ignited fuel. In an embodiment as shown in
As shown in
The processor 120 is configured to receive the signal from the detector 118 and generate one or more actuation signals. The controller 122 is configured to receive the actuation signals and tandemly control the fuel delivery systems 104 associated with the pre-determined cylinders out of the four cylinders 106, 108, 110, and 112 based on the actuation signals. In an embodiment, the pre-determined cylinders out of the four cylinders 106, 108, 110, and 112 may be selected based on an operating parameter of the multi-cylinder engine 102. In an embodiment as shown in
According to an aspect of the present disclosure, a change in the fuel type from the compression ignited fuel to the spark ignited fuel in the multi-cylinder engine 102 will be explained in the appended description pertaining to
In an embodiment as shown in
The multi-cylinder engine 102 may further include air inlet valves 138, and exhaust valves 140 associated with each of the cylinders 106, 108, 110, and 112. The air inlet valves 138 may be configured to supply air into the cylinders 106, 108, 110, and 112 while the exhaust valves 140 may be configured to allow by-products resulting due to combustion of fuel to escape into atmosphere.
In an embodiment as shown in
A firing order commonly known in the art may be selected for the cylinders 106, 108, 110, and 112 of the four-cylinder engine 102. Some of the commonly known firing orders are listed below.
For the purposes of understanding the various embodiments of the present disclosure, explanation for
For the purpose of the present disclosure, in an exemplary transitioning regime based on the operating parameter of the multi-cylinder engine 102, the pre-determined cylinders may be cylinders 106 and 110 out of the four cylinders 106, 108, 110, and 112 shown in
Referring to
Referring to
Referring to
Referring to
Referring to
In this manner, the controller 122 may be configured to tandemly control the fuel delivery systems 104 associated with the pre-determined cylinders 106 and 110 based on the actuation signals received by the controller 122. The tandem control of the fuel delivery systems 104, disclosed herein, may represent shutting off compression ignited fuel and initiating delivery of spark ignited fuel to the pre-determined cylinders 106 and 110 in a cylinder by cylinder or step-wise manner.
With reference to
In an embodiment, the controller 122 may be configured to shut off a delivery of the compression ignited fuel from the fuel delivery systems 104 associated with the pre-determined cylinders 106 and 110. In a further embodiment, the controller 122 may be configured to switch off a delivery of the spark ignited fuel from the fuel delivery systems 104 associated with the pre-determined cylinders 106 and 110. Therefore, the controller 122 may be configured to shut off a delivery of the compression ignited fuel and the spark ignited fuel to the pre-determined cylinders 106 and 110 such that the pre-determined cylinders 106 and 110 may execute one or more motoring cycles. Motoring cycles disclosed herein, may represent an idle reciprocation of a piston within a cylinder in the absence of fuel. The motoring cycle may include an intake stroke, one or more dry strokes based on an engine type, and an exhaust stroke. These strokes of the motoring cycles may occur in the absence of fuel thus helping to flush out any residual by-products left behind in the pre-determined cylinders 106 and 110 due to the ignition of the compression ignited fuel.
As shown in
It is to be noted that the motoring cycles of
In an embodiment, pre-determining the number of cylinders may be based on an operating parameter of the multi-cylinder engine 102. In a further embodiment, the operating parameter may be the load on the multi-cylinder engine 102. In another embodiment, the operating parameter may be the speed of the multi-cylinder engine 102.
In one embodiment, tandemly controlling the fuel delivery systems 104 may include tandemly shutting off a delivery of the compression ignited fuel from the fuel delivery systems 104 associated with the pre-determined cylinders 106 and 110. In a further embodiment, tandemly controlling the fuel delivery system 104 may include selectively switching on the delivery of the spark ignited fuel from the fuel delivery systems 104 associated with the pre-determined cylinders 106 and 110. In a further embodiment, the method may further include switching on one or more ignition sources 114 associated with the pre-determined cylinders 106 and 110.
When transitioning from the compression ignited fuel to the spark ignited fuel in a typical dual-fuel engine, residual by-products resulting from the combustion of the compression ignited fuel may be left behind in the cylinders of the engine. Pre-ignition characteristics of spark ignited fuels may be different from that of compression ignited fuels. The residual by-products left behind in the cylinders of the engine may cause detrimental effects such as knocking, or detonation from pre-ignition of the spark ignited fuel.
Further, conventional fuel changeover systems known in the art may allow a change in fuel type input to the engine. However, the conventional fuel changeover systems may change the fuel type in all of the cylinders of the engine at once. Therefore, the sudden change in fuel type may increase the knocking effect across all cylinders thereby reducing engine performance and power output instantaneously. Therefore, a decreased power output of the engine may be inadequate to drive loads such as a turbocharger which may require a substantial amount of thermal energy and kinetic energy from the exhaust gases.
The knocking effect may be reduced by gradually stepping up each cylinder 106, 108, 110, and 112 of the engine on the spark ignited fuel as compared to introducing the spark ignited fuel into all the cylinders 106, 108, 110, and 112 at once. In the power system 100 as shown in
In an embodiment, the knocking effect may be further reduced by flushing out the residual by-products prior to delivering the spark ignited fuel. In an embodiment as shown in
A person having ordinary skill in the art may acknowledge that sudden introduction of motoring cycles across most or all cylinders at once may lead to significant power drop in an engine and also stalling of the engine in some cases. However, with regards to the power system 100 disclosed herein, it may be noted that in one embodiment, the pre-determination of the number of cylinders may be done such that the load on the multi-cylinder engine 102 is driven by the remaining cylinders 108 and 112 operating on compression ignited fuel while the pre-determined cylinders 106 and 110 execute motoring cycles respectively.
In another embodiment, the pre-determination of the number of cylinders may be done such that the load on the multi-cylinder engine 102 is driven together by the pre-determined cylinders 106 and 110 and the remaining cylinders 108 and 112 operating on spark ignited fuel and compression ignited fuel respectively. Therefore, the controller 122 disclosed herein may effect a smooth transition from a compression ignited fuel to a spark ignited fuel in the multi-cylinder engine 102. Further, an occurrence of knocking in the multi-cylinder engine 102 may be avoided thereby reducing a likelihood of sudden power drops. Therefore, an implementation of the control system 116 disclosed herein in multi-cylinder engines 102 may improve engine performance and prolong engine life.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machine, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
