Abstract: A method of operating a gas or dual fuel engine having a plurality of cylinders, includes monitoring a characteristic of each of the plurality of cylinders during operation of the gas or dual fuel engine. The method also includes detecting a pre-ignition condition associated with one or more cylinders of the plurality of cylinders based on the monitored characteristic. The method further includes reducing fuel supply to the one or more cylinders having the pre-ignition condition. The fuel supply to remaining cylinders of the plurality of cylinders is increased, to maintain a constant power output of the gas or dual fuel engine. The method further includes adjusting an amount of air supplied to each of the plurality of cylinders based on the increased amount of fuel supplied to the remaining cylinders, to maintain an air-to-fuel ratio within a desired range.

Abstract: A method for controlling fuel flow in a multi fuel engine is disclosed. An input power for operating the multi fuel engine at a desired engine speed is determined and a fuel flow rate based on the input power, one or more fuel properties and a specified fuel substitution ratio for apportioning the plurality of fuels is determined. Also, a correction factor for the fuel flow rate based on a desired charge density, wherein the desired charge density is based at least on a relationship between an engine load and charge density is determined and a corrected fuel flow rate, based on the determined correction factor, is output to a corresponding actuator of a fluid flow control device for the one of the fuels to cause the corresponding actuator to provide the one of the plurality of fuels at the corrected fuel flow rate.

Abstract: A method for controlling an air-fuel ratio (AFR) in an engine powered by a gaseous fuel having an unknown composition may comprise receiving an assumed gas species composition for the gaseous fuel, and determining an assumed lower heating value (LHV) for the assumed gas species composition. The method may further comprise determining a perceived lower heating value (LHV) for the gaseous fuel based on a perceived gas mass flow and a gas energy flow for the gaseous fuel, and updating the assumed gas species composition until the assumed LHV and the perceived LHV are aligned. The method may further comprise determining a desired AFR and an airflow necessary to provide the desired AFR using the aligned gas species composition and a desired lambda (?), and adjusting an air system controller of the engine to provide the airflow.

Abstract: A method for estimating a specific gravity of a gaseous fuel is described. The gaseous fuel may power an engine and the engine may include a cylinder, a gas valve configured to supply an intake port of the cylinder with the gaseous fuel, a gas rail configured to deliver the gaseous fuel to the gas valve, and a microprocessor adapted to perform the method. The method may comprise establishing a pressure wave in the gas rail by opening and closing the gas valve, wherein the pressure wave travels at the speed of sound in the gaseous fuel. The method may further comprise determining a frequency of the pressure wave in the gas rail, and estimating the specific gravity of the gaseous fuel based on the frequency of the pressure wave.

Abstract: The disclosure relates to a system and method for determining the specific gravity of a fuel used in a dual fuel engine. The system includes a fuel rail, at least one sensor, and a processor. The method includes sensing and recording, with the at least one sensor and the at least one memory, a first pressure profile of a first fuel in the fuel rail and a second pressure profile of a second fuel in the fuel rail. The first fuel has a known specific gravity and the second fuel has an unknown specific gravity. The method further includes calculating the second specific gravity of the second fuel, with a processor, based on the first pressure profile, the second pressure profile, and the first specific gravity.

Abstract: A method for estimating a specific gravity of a gaseous fuel is described. The gaseous fuel may power an engine and the engine may include a cylinder, a gas valve configured to supply an intake port of the cylinder with the gaseous fuel, a gas rail configured to deliver the gaseous fuel to the gas valve, and a microprocessor adapted to perform the method. The method may comprise establishing a pressure wave in the gas rail by opening and closing the gas valve, wherein the pressure wave travels at the speed of sound in the gaseous fuel. The method may further comprise determining a frequency of the pressure wave in the gas rail, and estimating the specific gravity of the gaseous fuel based on the frequency of the pressure wave.

Abstract: A control system for a dual gaseous and liquid fuel engine includes an electronic controller configured to receive data from a plurality of sensing mechanisms indicative of an error in a plurality of different engine operating parameters. The electronic controller is further configured to determine a highest priority one of the errors, and limit substitution of the gaseous fuel responsive to a normalized value thereof.

Abstract: A method for controlling an air-fuel ratio (AFR) in an engine powered by a gaseous fuel having an unknown composition may comprise receiving an assumed gas species composition for the gaseous fuel, and determining an assumed lower heating value (LHV) for the assumed gas species composition. The method may further comprise determining a perceived lower heating value (LHV) for the gaseous fuel based on a perceived gas mass flow and a gas energy flow for the gaseous fuel, and updating the assumed gas species composition until the assumed LHV and the perceived LHV are aligned. The method may further comprise determining a desired AFR and an airflow necessary to provide the desired AFR using the aligned gas species composition and a desired lambda (?), and adjusting an air system controller of the engine to provide the airflow.

Abstract: The disclosure provides a method to operate an engine system. The method begins by determination of a current NOx value. If the current NOx value is greater than a first predetermined NOx target, an air-fuel ratio (AFR) set-point is adjusted by a first predetermined value in towards a rich AFR. Upon detection of the current NOx value below the first predetermined NOx target, a first average of NOx values for a first predetermined time is determined. The AFR set-point is adjusted by a second predetermined value and a second average of NOx values for a second predetermined time is determined. A delta NOx value is determined as a difference between the first average and the second average and compared with a second predetermined NOx target. The AFR set-point is determined when the delta NOx value is below the second predetermined NOx target.

Abstract: The present invention overcomes the inadequacies inherent in the known methods for generating libraries of antibody-encoding polynucleotides by specifically designing the libraries with directed sequence and length diversity.

Abstract: A method to control a wastegate valve actuator by determining a NOx deadband with hysteresis for an engine controller is disclosed. This NOx deadband defines an outer band and an inner band. In this method, a NOx sensor keep sensing the NOx level in the exhaust gases and accordingly the engine controller sends commands to the wastegate valve actuator. At the NOx level less than inner band and the outer band, engine controller remains at deactivated state. When the NOx level goes outside the outer band, the engine controller sends dither command to the wastegate valve actuator and continues to send the dither command until the NOx level does not reach inside the NOx inner band. This method improves life of the wastegate valve assembly as separate activating and deactivating bands for the engine controller ensures less command fluctuations for the wastegate valve actuator.

Abstract: A method for controlling fuel flow in a multi-fuel engine is disclosed. The method includes determining an estimated lower heating value (LHV) of a gaseous fuel by, at least, comparing a mapped volume flow value with an input volume flow value, the input volume flow value based on the input power. The method further includes determining a gaseous fuel flow rate for the gaseous fuel, the gaseous fuel flow rate based on, at least, a specific fuel substitution ratio of the gaseous fuel and a secondary fuel and the estimate LHV of the gaseous fuel source.

Abstract: The present invention overcomes the inadequacies inherent in the known methods for generating libraries of antibody-encoding polynucleotides by specifically designing the libraries with directed sequence and length diversity.

Abstract: A method for controlling an internal combustion engine operating on at least partly gaseous fuel is disclosed. The method may include providing a desired burn rate profile corresponding to a desired operation of the internal combustion engine. The method may further include selecting first operating parameters such that an operation of the internal combustion engine with a first gas composition produces a first burn rate profile that corresponds to the desired burn rate profile. The method may also include operating the internal combustion engine with the first operating parameters using a second gas composition. The method may include determining that the second burn rate profile differs from the desired burn rate profile. In addition, the method may include adjusting an operating parameter from among the first operating parameters of the internal combustion engine to approach the desired burn rate profile.

Abstract: A method for controlling an internal combustion engine is disclosed. The method may include receiving knock data corresponding to knock levels over a time period. The method may also include determining from the knock data whether the knock levels change over the time period. Further, the method may include determining that a variation in the gas composition of the gaseous fuel supplied to the internal combustion engine has occurred when the knock levels change over the time period. In addition, the method may include adjusting an operating condition of the internal combustion engine to adapt a knock susceptibility of the internal combustion engine to the varying gas composition.

Abstract: The disclosure relates to a system and method for determining the specific gravity of a fuel used in a dual fuel engine. The system includes a fuel rail, at least one sensor, and a processor. The method includes sensing and recording, with the at least one sensor and the at least one memory, a first pressure profile of a first fuel in the fuel rail and a second pressure profile of a second fuel in the fuel rail. The first fuel has a known specific gravity and the second fuel has an unknown specific gravity. The method further includes calculating the second specific gravity of the second fuel, with a processor, based on the first pressure profile, the second pressure profile, and the first specific gravity.

Abstract: A fuel injection timing management system for a dual fuel engine is configured to determine a first diesel injection timing corresponding to a first mode of operation of the engine system and a second diesel injection timing corresponding to a second mode of operation. The system may further determine a direction of change in a mode of operation of the engine system, and selectively perform a change in the diesel injection timing from the first diesel injection timing to the second diesel injection timing at a first rate of transition or a second rate of transition, based on the direction of change in a mode of operation of the engine system.

Abstract: A method for controlling fuel flow in a multi fuel engine is disclosed. An input power for operating the multi fuel engine at a desired engine speed is determined and a fuel flow rate based on the input power, one or more fuel properties and a specified fuel substitution ratio for apportioning the plurality of fuels is determined. Also, a correction factor for the fuel flow rate based on a desired charge density, wherein the desired charge density is based at least on a relationship between an engine load and charge density is determined and a corrected fuel flow rate, based on the determined correction factor, is output to a corresponding actuator of a fluid flow control device for the one of the fuels to cause the corresponding actuator to provide the one of the plurality of fuels at the corrected fuel flow rate.

Abstract: Controlling intake pressure in a gaseous fuel internal combustion engine includes calculating a control term in an intake pressure control loop based on a pressure error, and adjusting a throttle valve and a second valve responsive to the control term in first and second control loop cycles. The second valve is within a return conduit returning compressed gases from a location downstream a compressor to a location upstream. A pressure of gaseous fuel and air within the intake conduit is changed via the adjustments so as to reduce the pressure error.

Abstract: A method of operating a gas or dual fuel engine having a plurality of cylinders, includes monitoring a characteristic of each of the plurality of cylinders during operation of the gas or dual fuel engine. The method also includes detecting a pre-ignition condition associated with one or more cylinders of the plurality of cylinders based on the monitored characteristic. The method further includes reducing fuel supply to the one or more cylinders having the pre-ignition condition. The fuel supply to remaining cylinders of the plurality of cylinders is increased, to maintain a constant power output of the gas or dual fuel engine. The method further includes adjusting an amount of air supplied to each of the plurality of cylinders based on the increased amount of fuel supplied to the remaining cylinders, to maintain an air-to-fuel ratio within a desired range.