GB2548606A

GB2548606A - Method of operating engine of cogeneration plant

Info

Publication number: GB2548606A
Application number: GB1604952.0A
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: 2016-03-23
Filing date: 2016-03-23
Publication date: 2017-09-27
Anticipated expiration: 2036-03-23
Also published as: GB201604952D0; DE102017106031A1; GB2548606B

Abstract

Disclosed is a method of operating an internal combustion engine of a cogeneration plant. The method includes receiving an input indicative of a desired electric power and a desired heat energy to be generated by a control unit. The method further includes comparing the input with a predefined map stored in the control unit. The predefined map includes multiple relationships defined between one or more operating parameters of the engine and at least one of heat energy, electrical power and a combination of the heat energy and the electrical power to be generated. The method further includes selecting at least one of the multiple relationships from the predefined map based on the comparison of the input with the predefined map. The method further includes controlling the one or more operating parameters associated with the at least one of the multiple relationships to derive the desired electric power and the desired heat energy. The method allows accurate control of an engine to provide combined heat and power.

Description

METHOD OF OPERATING ENGINE OF COGENERATION PLANT Technical Field [0001] The present disclosure relates to a cogeneration plant and more particularly relates to a method of operating an engine of the cogeneration plant to generate electric power and heat energy.

Background [0002] Combined electric power and heat energy generation system, also known as a cogeneration system, includes an Internal Combustion (IC) engine coupled to a generator. The IC engine is operated to generate electric power and heat energy. Combustion of fuel in the IC engine generates mechanical power, the mechanical power is therein converted to electric power. The IC engine is operated to simultaneously generate heat energy from various heat recovery components of the engine, such as an exhaust of the IC engine. The electric power and heat energy is generated for commercial benefits and may be supplied to customers directly or may also be stored in power grids for future usage. The IC engine and the generator are operated by considering several parameters power based on a customer’s requirement. The customer’s requirement may include generating maximum quantity of electrical power and maximum quantity of heat energy by using a minimal quantity of fuel supply. The customer requirement may vary due to demand supply of the electric power and the heat energy.

[0003] The customer requirement for electric power and the heat energy may also change fluctuation in market price of electric power and heat energy vis-a-vis demand. The market price of the electric power and the heat energy often tends to fluctuate due to factors including, but not limited to, climatic conditions, fluctuation in fuel price, varying production rates, varying demand, political conditions, tax rates etc. In order to meet the demand in the market, the customers operate the engine and generator for generating more electric power or heat energy by increasing fuel supply. Sometimes, the engine and generator may be operated for longer hours to meet the demand. Due to increased fuel supply and increased operational hours, emission coming out from the engine may be increased. Thus, the increased emission from the engine may increase the emission to the atmosphere and may exceed environmental standards. Also, overall efficiency and durability of the engine and generator may reduce. Thus, the engine and generator may often servicing and maintenance, increasing cost and down time of the cogeneration plant.

[0004] US Patent Number 4,873,840 (the ’840 patent) describes a cogeneration system The co-generation system is used for producing electricity, heating and cooling and including a combustion unit, a boiler connected to the combustion unit, a steam engine and an electrical generator driven to the steam engine. A condenser is connected to the steam exhaust port of the steam engine, the condenser supplying heat to a heat system and causing condensation of the steam discharged by the exhaust port. An absorption cooler is connected to the exhaust port of the steam engine, the absorption cooler for cooling fluid of a cooling system. A heat pump or centrifugal cooler can also be driven by an output shaft of the steam engine. The co-generation system can also include a flue gas cooler for further transfer of heat to heating system. The ’840 patent discloses separate units for producing electricity, heat and cooling of the steam engine. The cogeneration system including separate units may lead to complexity of the cogeneration system and may increase production cost for generating electrical power and heat energy.

Summary of the Disclosure [0005] In the present disclosure, a method of operating an engine is disclosed. The engine is coupled to a generator for generating electric power. The engine is further coupled to a heat recovery system for generating heat energy. The method includes receiving an input indicative of a desired electric power and a desired heat energy to be generated by a control unit. The control unit is in electric communication with the generator and the heat recovery system. The method further includes comparing the input with a predefined map stored in the control unit. The predefined map includes multiple relationships defined between one or more operating parameters of the engine and at least one of heat energy, electrical power and a combination of the heat energy and the electrical power to be generated. The operating parameters include Start of Combustion (SOC) in a combustion cycle during operation of the engine, an intake manifold air pressure, an intake manifold air temperature, an ignition energy, a compression ratio, and opening and closing time of an intake valve and an exhaust valve. The method further includes selecting at least one of the multiple relationships from the predefined map based on the comparison of the input with the predefined map. The method further includes controlling the one or more operating parameters associated with the at least one of the multiple relationships to derive the desired electric power and the desired heat energy.

[0006] Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings [0007] FIG. 1 is a schematic diagram of a cogeneration plant, according to an embodiment of the present disclosure; [0008] FIG. 2 is a block diagram of the cogeneration plant of FIG. 1; and [0009] FIG. 3 is a flow chart of a method of operating an engine of the cogeneration plant of FIG. 1 for generating a desired heat energy and a desired electric power.

Detailed Description [0010] Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts. Moreover, references to various elements described herein, are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. It may be noted that any reference to elements in the singular may also be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claim.

[0011] FIG. 1 illustrates a schematic diagram of a cogeneration plant 10 according to an embodiment of the present disclosure. The cogeneration plant 10 includes an engine 12 coupled to a generator 14 for generating electric power and a heat recovery system 16 for generating heat energy. The engine 12 may be a multi-cylinder engine having an inline configuration, a radial configuration, or any other configurations known in the art. The engine 12 includes a combustion unit 18, operated by a compression ignition method or a spark-ignition method. The cogeneration plant 10 is operated either in an electric power generation mode to generate the electric power and a heat energy generation mode to generate the heat energy. In an example, the cogeneration plant 10 is operated in a controlled manner to generate desired electric power and/or desired heat energy. The electric power is generated by the generator 14 by converting mechanical power generated by combustion of fuel in the combustion unit 18 of the engine 12. The combustion in the combustion unit 18 of the engine 12 is controlled by varying various parameters including, but not limited to, air-fuel ratio, intake manifold air temperature, intake manifold air pressure, and quantity of fuel supplied to the combustion unit 18. Thus, the electric power generation and the heat energy generation may also be varied by varying the various parameters including, but not limited to, the air-fuel ratio, the intake manifold air temperature, the intake manifold air pressure, and the quantity of fuel supplied to the combustion unit 18.

[0012] The engine 12 is operably coupled to the generator 14, such that the mechanical power generated by the engine 12 is transferred to the generator 14 for generating the electric power. During the electric power generation mode, the engine 12 is operated for combustion by supplying the fuel and an intake air to the combustion unit 18. The engine 12 includes an air intake unit 20 for preconditioning and delivering the intake air to the combustion unit 18. The “preconditioned intake air” as used herein refers to conditioning the intake air by reducing or increasing temperature of the intake air. For example, if the temperature of the intake air is more than a temperature required for combustion of the fuel, then the temperature of the intake air is reduced by absorbing heat from the intake air, and if the temperature of the intake air is less than the temperature required for combustion of the fuel, then the temperature of the intake air is increased by heating the intake air using an intake air heater 22. For example, during combustion of the fuel in the combustion unit 18, the intake air heater 22 increases temperature of the intake air above ambient temperature, from about 25° C to about 45 0 C. Due to the combustion of the fuel, the mechanical power is generated inside the combustion unit 18 which is further transferred to the generator 14 for generating the electric power. Exhaust gas (not shown) is emitted from the combustion unit 18 and is made to pass through a cleaning unit 52 of the cogeneration plant 10 via an exhaust gas circuit 48 for reducing temperature of the exhaust gas before releasing the exhaust gas to atmosphere. In an example, the exhaust gas may be recirculated for increasing temperature of the intake air. In another example, the exhaust gas is made to pass through the heat recovery system 16 for absorbing heat from the exhaust gas.

[0013] The engine 12 of the cogeneration plant 10 is also operated in the heat energy generation mode for generating heat with a given supply of the fuel to the engine 12. During the heat energy generation mode, the parameters including, but not limited to, the air-fuel ratio, the intake manifold air temperature, the intake manifold air pressure, and the quantity of fuel supplied to the combustion unit 18 may be varied. The heat energy generation mode involves heat recovery process. The heat recovery process includes multi stage heat recovery processes.

[0014] During a first stage of recovery process, heat from the exhaust gas after the combustion of the fuel is recovered. The exhaust gas from the combustion unit 18 is passed through an exhaust gas heat exchanger 40 of the heat recovery system 16 through the exhaust gas circuit 48. The exhaust gas heat exchanger 40 absorbs the heat from the exhaust gas, and thereby decreases temperature of the exhaust gas. The exhaust gas having reduced temperature is further expelled from the exhaust gas heat exchanger 40 to the cleaning unit 52. The cleaning unit 52 may remove hazardous oxides in the exhaust gas, such as, but not limited to, COx and NOx. The exhaust gas heat exchanger 40 is adapted to further transfer absorbed heat to a heat recovery unit 34 via a heat recovery circuit 36.

[0015] In a second stage of the heat recovery process, heat from the engine 12 is recovered by a water jacket circuit 46 and a lubrication circuit 44. In the water jacket circuit 46, a coolant, including, but not limited to, water is circulated through the water jacket circuit 46 to absorb the heat generated in an engine body due to the combustion process. Hot water is made to pass through a water jacket heat exchanger 42 of the heat recovery system 16 to absorb the heat from the hot water. Thus, the heat from the engine body is recovered by the coolant circuit 30. The water jacket heat exchanger 42 is adapted to further transfer absorbed heat to the heat recovery unit 34 via the heat recovery circuit 36.

[0016] Further, in the second stage heat recovery process, heat is recovered from lubrication oil circulated between the lubrication circuit 44 and the engine 12. In the lubrication circuit 44, a lubricant is circulated through movable components including, but are not limited to, a piston and a cylinder of the engine 12 during the combustion process. The lubricant absorbs heat from the movable components and made to pass through a lubrication oil heat exchanger 38 of the heat recovery system 16 to absorb the heat from the lubricant. Thus, the heat from the engine 12 is recovered by the lubrication circuit 44. The lubrication oil heat exchanger 38 is adapted to further transfer absorbed heat to a first intake air heat exchanger 24 via a circuit 39.

[0017] In a third stage of heat recovery process, heat is recovered from the intake air. The air intake unit 20 of the engine 12 includes the first intake air heat exchanger 24 and a second intake air heat exchanger 26 adapted to absorb excess heat from the intake air. The first intake air heat exchanger 24 may constitute a high temperature charge air cooler. The first intake air heat exchanger 24 extracts heat from the intake air received from the intake air heater 22. For example, the first intake air heat exchanger 24 extracts heat from the intake air having about 260°C to about 90°C. The second intake air heat exchanger 26 may constitute a low temperature charge air cooler. The second intake air heat exchanger 26 further extracts heat from the intake air received from the first intake air heat exchanger 24. For example, the second intake air heat exchanger 26 extracts heat from the intake air having temperature of about 90°C and reduces the temperature of the intake air to about 45°C. The second intake air heat exchanger 26 further supplies the intake air having reduced temperature to a cooling unit 28 via a cooling circuit 30. In an example, the cooling unit 28 cools the intake air to the ambient temperature. The air intake unit 20 may further include a turbocharger (not shown) adapted to connect with the intake air heater 22. The turbocharger compresses the intake air received from the intake air heater 22 for increasing pressure of the intake air.

[0018] The cogeneration plant 10 further includes a control unit 50 for controlling the generation of the electric power and the heat energy. The control unit 50 is configured to communicate with the engine 12, the generator 14, the air intake unit 20, the heat recovery unit 34, and a Human Machine Interface (HMI) 54. The control unit 50 may be a processor including a single processing unit or a number of processing units, all of which may include multiple computing units. The explicit use of term ‘processor’ should not be construed to refer exclusively to hardware capable of executing a software application. Rather, in this example, the control unit 50 may be implemented as one or more microprocessors, microcomputers, digital signal processor, central processing units, state machine, logic circuitries, and/or any device that is capable of manipulating signals based on operational instructions. Among the capabilities mentioned herein, the control unit 50 may also be configured to receive, transmit, and execute computer-readable instructions.

[0019] The control unit 50 of the cogeneration plant 10 includes a data repository 60. The “data repository” 60 as referred herein refers to a memory module capable of storing data such as a predefined map. The term “predefined map” refers to a relationship between operating parameters of the engine 12 for generating a desired electric power and a desired heat energy. The term “operating parameters” as used herein include, but not limited to, Start of Combustion (SOC) in a combustion cycle during operation of the engine 12, the intake manifold air pressure (IMAP), the intake manifold air temperature (IMAT), an ignition energy, a compression ratio, and opening and closing time of an intake valve and an exhaust valve. A manufacturer of the engine 12 may generate the predefined map based on a series of tests and simulations. The engine 12 is adapted to generate the desired electric power and the desired heat energy by varying the operating parameters of the engine 12 based on instruction of the control unit 50.

[0020] An input indicative of the desired electric power and the desired heat energy is communicated through the HMI 54 by an operator. The input from the HMI54 is received by the control unit 50. Based on the input, the control unit 50 controls the operating parameters of the engine 12 to derive the desired electric power and the desired heat energy. The term “desired electric power” refers to a quantity of the electric power that is required to be generated based on demand from a customer. The term “desired heat energy” refers to a quantity of the heat energy that is required to be generated based on demand of the customer. The demand of the desired electric power and the demand of the desired heat energy may change due to factors such as, but not limited to, market price of the electric power and the heat energy. The market price of the electric power may vary due to factors including, but not limited to, climatic conditions, fluctuation in fuel price, varying production rates, varying demand, political conditions, and tax rates.

[0021] FIG. 2 illustrates a block diagram of the cogeneration plant 10. The cogeneration plant 10 includes the engine 12 having the combustion unit 18, a fuel ignition unit 56 and a fuel supply unit 58. The cogeneration plant 10 further includes the heat recovery system 16, the generator 14 and the control unit 50. The control unit 50 is configured to be in electric communication with the engine 12. The engine 12 is further mechanically coupled with the generator 14 and fluidly communicates with the heat recovery system 16. The control unit 50 is configured to provide an instruction to the engine 12, the generator 14 and the heat recovery system 16 for generating the desired electric power and the desired heat energy.

[0022] The control unit 50 is further in communication with the HMI 54 for receiving the input from the operator. The HMI 54 and the control unit 50 are in electric communication with each other via a wired communication and/or a wireless communication. The HMI 54 facilitates the operator to provide the input indicative of the desired electric power and the desired heat energy to be generated. The HMI 54 in communication with the control unit 50 is configured to provide the input to the control unit 50. The HMI 54 may be an integral part of the cogeneration plant 10 or may be an external device adapted to connect with the cogeneration plant 10. The control unit 50 is configured to vary the operating parameters of the engine 12 based on the input received by the HMI 54.

[0023] The control unit 50 includes the data repository 60 for storing the predefined map. Based on the input received from the HMI 54, the control unit 50 is configured to communicate a signal indicative of the ignition energy and an amount of fuel required in the combustion unit 18. The amount of fuel required in the combustion unit 18 varies based on the desired electric power and the desired heat energy. The engine 12 of the cogeneration plant 10 includes the fuel ignition unit 56, which is configured to control air-fuel mixture supplied to the combustion unit 18 based on the signal received from the control unit 50. The ignition energy may be defined depending on the type of internal combustion engine 12, for example, an air-to-fuel ratio in a pre-combustion chamber, and an amount and/or pressure of the fuel supplied to the combustion unit 18.

[0024] The engine 12 of the cogeneration plant 10 further includes the fuel supply unit 58 for supplying the fuel to the combustion unit 18 based on the signal received from the control unit 50. Tn one example, the fuel supply unit 58 may supply liquid fuel to the combustion unit 18, if the engine 12 is a liquid powered diesel or Otto engine. The fuel supply unit 58 may include fuel admission and fuel injector for injecting one of, but not limited to, liquid and gaseous fuel into cylinders of the combustion unit 18. The control unit 50 monitors generation of the electric power by the generator 14 and the heat energy recovered by the heat recovery system 16.

[0025] In one example, an intake manifold of the engine 12 may be adapted to incorporate a pressure sensor. The pressure sensor may communicate a signal indicative of the intake manifold air pressure with the control unit 50. In another example, the intake manifold of the engine 12 may be adapted to incorporate a temperature sensor. The temperature sensor may communicate a signal indicative of the intake manifold air temperature with the control unit 50.

[0026] FIG. 3 illustrates a flow chart of a method 62 of operating the engine 12 for generating the desired electric power and the desired heat energy. The steps in which the method 62 is described are not intended to be construed as a limitation, and any number of steps can be combined in any order to implement the method 62. The method 62 may be implemented in any suitable hardware, such that the hardware employed can perform the steps of the method 62 readily and on a real-time basis.

[0027] The engine 12 is operated by controlling the operating parameters of the engine 12 by the control unit 50. The HMI 54 in communication with the control unit 50 is configured to provide the input to the control unit 50. The input is provided by the operator via the HMI 54 for generating the desired electric power and the desired heat energy by the cogeneration plant 10. At a step 64, the control unit 50 receives the input provided by the operator of the cogeneration plant 10. The input is indicative of the desired electric power and the desired heat energy to be generated. In one example, the operator is required to manually provide the input to the HMI 54, as the price of the desired electric power and the desired heat energy changes due to various situations, such as climatic changes, and demand variations. The operator, based on the price and demand of the electric power and the heat energy, provides the input indicative of the desired electric power and the desired heat energy.

[0028] After receiving the input by the control unit 50, which is based on the desired electric power and the desired heat energy, the control unit 50, at a step 66, compares the input with the predefined map stored in the data repository 60. The predefined map includes the multiple relationships. The term “multiple relationships” as used herein is a relationship or correlation between the one or more operating parameters of the engine 12, and any one of the electric power to be generated, the heat energy to be generated and combination of the electric power and the heat energy to be generated. The desired electric power and the desired heat energy are generated by varying the operating parameters of the engine 12 including, but not limited to, the Start of Combustion (SOC) in the combustion cycle during operation of the engine 12, the intake manifold air pressure, the intake manifold air temperature, the ignition energy, the compression ratio, and opening and closing time of the intake valve and the exhaust valve. Upon receiving the input from the operator, the control unit 50 is configured to determine actual value of the various operating parameters of the engine 12, such as the Start of Combustion (SOC) in the combustion cycle during operation of the engine 12, the intake manifold air pressure, the intake manifold air temperature, the ignition energy, the compression ratio, and opening and closing time of the intake valve and the exhaust valve during operation of the engine.

[0029] After comparing the input with the predefined map, the control unit 50 is configured to select one relationship of the multiple relationships from the predefined map, at a step 68. In an example, the multiple relationships may include generating optimum electric power or optimum heat energy or optimum combination of the electric power and the heat energy. The selection of one of the optimum electric power or the optimum heat energy or the optimum combination of the electric power and the heat energy is based on factors including, but not limited to, climatic conditions, fluctuation in fuel price, varying production rates, varying demand, political conditions, and tax rates. After the selection of one relationship among the multiple relationships, at a step 70, the control unit 50 is configured to control the one or more operating parameters of the engine 12 associated with the at least one relationship for generating the desired electric power and/or the desired heat energy.

[0030] In one example, it may be observed that the demand for the heat energy may increase due to change in climatic conditions, such as extreme cold weather in winter season. Due to the increased demand for the heat energy, the price of the heat energy per unit may also tend to increase. Thus, selecting one relationship among the multiple relationships, in this illustrated example, may be to generate optimum heat energy at less fuel consumption and with less exhaust emission. As such, the operator of the cogeneration plant 10 provides an input through the HMI 54 to the control unit 50 for generating the optimum heat energy based on the demand and price of the heat energy. The control unit 50, upon receiving the input from the operator for generation of the optimum heat energy, provides an instruction signal to the engine 12 of the cogeneration plant 10 for varying the one or more operating parameters associated with the selected relationship for obtaining optimum heat energy from the cogeneration plant 10. The control unit 50 may communicate with at least one of the intake air heater 22, the turbocharger provided in the air intake unit 20, the fuel ignition unit 56 and the fuel supply unit 58 to vary the one or more operating parameters associated with the selected relationship.

[0031] Also, the heat from the engine 12 is recovered at various sources for generating the desired heat energy from the cogeneration plant 10. The various sources for recovering the desired heat energy in the cogeneration plant 10 includes, but not limited to, the exhaust gas heat exchanger 40, the lubrication oil heat exchanger 38, and the water jacket heat exchanger 42.

[0032] In another example, it may be observed that the demand for the electric power may increase due to change in industrial development and urbanization. Due to the increased demand for the electric power, the price of the electric power per unit may also tend to increase. Thus, selecting one relationship among the multiple relationships, in this illustrated example, may be to generate optimum electric power at less fuel consumption and with less exhaust emission. As such, the operator of the cogeneration plant 10 provides an input through the HMT 54 to the control unit 50 for generating the optimum electric power based on the demand and price of the electric power. The control unit 50, upon receiving the input from the operator for generation of the optimum heat energy, provides an instruction signal to the engine 12 of the cogeneration plant 10 for varying operating parameters associated with the selected relationship for obtaining optimum electric power from the cogeneration plant 10. The control unit 50 may communicate with at least one of the intake air heater 22, the turbocharger, the fuel ignition unit 56 and the fuel supply unit 58 to vary the one or more operating parameters associated with the selected relationship.

[0033] In yet another example, it may be observed that the demand for both the heat energy and the electric power may proportionally arise due to change in climatic conditions, such as extreme cold weather in winter season and change in industrial development and urbanization. Due to the increased demand for the electric power and the heat energy, the prices of both the electric power and heat energy may also tend to increase. Thus, selecting one relationship among the multiple relationships, in this illustrated example, may be to generate optimum electric power and optimum heat energy. As such, the operator of the cogeneration plant 10 provides an input through the HMI 54 to the control unit 50 for generating the optimum electric power and the optimum heat energy based on the demand and price of the electric power and the heat energy.

[0034] The control unit 50, upon receiving the input from the operator for generation of the optimum electric power and the optimum heat energy, provides an instruction signal to the engine 12 of the cogeneration plant 10 for varying the one or more operating parameters associated with the selected relationship for obtaining the optimum electric power and the optimum heat energy from the cogeneration plant 10. The control unit 50 may communicate with at least one of the intake air heater 22, the turbocharger provided in the air intake unit 20, the fuel ignition unit 56 and the fuel supply unit 58 to vary the one or more operating parameters associated with the selected relationship. Further, the control unit 50 may control opening and closing time of the intake valve and the exhaust valve based on the selected relationship. The control unit 50 further communicates with the heat recovery system 16 and the generator 14 for generating the combination of optimum electric power and the heat energy. In yet another example, the one or more operating parameters of the engine 12 associated with the relationship selected based on the input from the operator is controlled to generate any optimum combination of desired electric power and the heat energy.

[0035] In another embodiment, the predefined map may be further defined based on a correlation between the operating parameters of the engine 12, such as the Start of Combustion (SOC) in the combustion cycle during operation of the engine 12, the intake manifold air pressure (IMAP), the intake manifold air temperature (IMAT), the ignition energy, the compression ratio, and opening and closing time of the intake valve and the exhaust valve of the engine 12 for generating the desired electric power and the desired heat energy. With such correlation, one or more operating parameters of the engine 12 may be controlled to obtain the optimum electric power and the optimum heat energy.

Industrial Applicability [0036] The present disclosure relates to the cogeneration plant 10 and the method 62 of operating the engine 12. The operating parameters to derive the desired electric power and the desired heat energy are controlled by the control unit 50, thereby overcoming the requirement of separate engines, generators and heat recovery systems. As such, the engine 12 may facilitate operating the cogeneration plant 10 based on the desired electric power and the desired heat energy. Recycling of the cooled intake air back to the intake air heater 22 may reduce requirement of supplying fresh intake air into the intake air heater 22 by the air intake unit 20. Further, the cogeneration plant 10 of the present disclosure facilitates generating any combination of the optimum electric power and the optimum heat energy based on the input from the operator. It may also be understood that various operating parameters of the engine 12 apart from the Start of Combustion, the intake manifold air pressure, the intake manifold air temperature, the ignition energy, the compression ratio, and the opening and closing time of the intake valve and the exhaust valve may be considered for controlling the operation of the engine 12 to generate any combination of the optimum electric power and the optimum heat energy.

[0037] 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 machines, 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.

Claims

Claim What is claimed is:
1. A method of operating an engine, the engine is coupled to a generator for generating electric power and coupled to a heat recovery system for generating heat energy, the method comprising: receiving, by a control unit, an input indicative of a desired electric power and a desired heat energy to be generated, wherein the control unit is in electric communication with the generator and the heat recovery system; comparing the input with a predefined map stored in the control unit, wherein the predefined map includes multiple relationships defined between one or more operating parameters of the engine and at least one of heat energy, electrical power and a combination of the heat energy and the electrical power to be generated, and wherein the operating parameters include Start of Combustion (SOC) in a combustion cycle during operation of the engine, an intake manifold air pressure, an intake manifold air temperature, an ignition energy, a compression ratio, and opening and closing time of an intake valve and an exhaust valve; selecting at least one of the multiple relationships from the predefined map based on the comparison of the input with the predefined map; and controlling the one or more operating parameters associated with the at least one of the multiple relationships to derive the desired electric power and the desired heat energy.