Dual fuel engine system and method for controlling dual fuel engine system
A method for controlling a dual fuel engine system includes determining a friction power loss amount of an internal combustion engine of the dual fuel engine system, where the friction power loss amount is based on an engine speed of the internal combustion engine and a friction torque estimate. The method also includes determining an accessory power loss amount of a power of the internal combustion engine, where the accessory power loss amount is based on the engine speed and an accessory torque estimate. The method further includes estimating a net engine power amount based on the accessory power loss amount and a brake power amount of the internal combustion engine, estimating an indicated diesel power, and estimating, based on the estimated net engine power, a first indicated engine power and a first gas power.
1 . A dual fuel engine system operable in a dual fueling mode, comprising: at least one controller in communication with an engine, the at least one controller being configured to:
measure an engine speed of the engine; estimate an engine power amount;
determine a rated power amount based on the engine power amount and a rated power limit of the engine;
determine a base gas substitution rate target for the engine based on the engine speed, the rated power amount, an intake manifold temperature, and an estimated methane number; and
determine a gas power target for the engine based on the base gas substitution rate target, the estimated engine power amount, and a friction power loss amount;
Control an actuator based on the gas power target.
2 . The system of claim 1 , wherein the at least one controller is further configured to determine a first indicated engine power based on the estimated engine power amount and the friction power loss amount.
3 . The system of claim 2 , wherein the at least one controller is further configured to determine a second indicated engine power based on a gas lower heating value (LHV), a total gas flow estimate, and a diesel power estimate.
4 . The system of claim 3 , wherein the at least one controller is configured to, responsive to a comparison of at least one of the first indicated engine power or the second indicated engine power to a predetermined threshold, initiate one or more engine protective protocols.
5 . The system of claim 3 , wherein the LHV is based on a first gas power, a gas flow estimate, and a thermal efficiency correction coefficient.
6 . The system of claim 4 , wherein the one or more engine protective protocols comprises temporarily disabling the dual fueling mode.
7 . The system of claim 4 , wherein the one or more engine protective protocols comprises reducing the engine speed.