Systems, methods and apparatus for controlling operation of dual fuel engines are disclosed that regulate the fuelling amounts provided by a first fuel and a second fuel during operation of the engine. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The fuelling amounts are controlled to improve operational outcomes of the duel fuel engine.

An engine control system is a system configured to selectively switch between first fuel and second fuel and perform an operation control of a single engine, including: a sensor configured to detect an oxygen concentration of an exhaust gas that is exhausted from the engine; and a control device configured to perform an air-fuel ratio feedback control such that an air-fuel ratio becomes a target air-fuel ratio based on an output signal of the sensor, wherein the control device calculates a correction coefficient of an air-fuel ratio feedback control during an operation with the second fuel, and further stores a fuel composition correction coefficient that is a value in a predetermined range and corrects a difference between the calculated correction coefficient and a targeted correction coefficient arising from a change in composition of the second fuel.

Methods and systems are providing for improving zero flow lubrication (ZFL) of a high pressure fuel pump coupled to direct fuel injectors via a direct injection fuel rail. A ZFL transfer function for the fuel pump is learned while fuel is at non-nominal fuel bulk modulus conditions and corrected for variations from a nominal fuel bulk modulus estimate. When zero flow lubrication of the pump is requested, the pump is operated with a duty cycle based on the learned transfer function and an instantaneous estimate of the fuel bulk modulus to compensate for differences in fuel condition from the nominal fuel bulk modulus estimate.

A system and method for detecting pressure deviation of a first fluid in an engine is disclosed. The method may comprise calculating, for each of a plurality of measurements, a delta between an actual first fluid pressure and a target pressure, summing each delta obtained from the calculating, and determining pressure deviation of the first fluid based on a cumulative sum of the deltas. In an embodiment, the first fluid may be natural gas.

In a method and an arrangement for determining a fuel quality of a fuel for a combustion engine fuel is conveyed from a low pressure fuel tank to a high-pressure volume, and injected into at least one cylinder of the combustion engine. A control valve is provided for controlling directly or indirectly the amount of fuel injected into the at least one cylinder. An actual value of a timing signal of the control valve is compared to a reference value of the timing signal of the control valve and a fuel quality parameter is derived from a difference between the actual value and the reference value of the timing signal of the control valve and/or that a fuel quality parameter is derived from a gradient of the pressure increase during a build-up phase of the pressure in the high-pressure volume compared to a reference value of the gradient of the pressure increase in the high-pressure volume.

A fuel control system of a vehicle includes a first storing module that, in response to receipt of a vehicle shutdown command, stores a first temperature of liquefied petroleum gas (LPG) within an LPG fuel rail of an engine and a first pressure of LPG within the LPG fuel rail. A second storing module, in response to receipt of a vehicle startup command, stores a second temperature of LPG within the LPG fuel rail and a second pressure of LPG within the LPG fuel rail. A butane module determines an amount of butane in the LPG based on the first temperature, the first pressure, the second temperature, and the second pressure. A fuel control module controls LPG fueling of the engine based on the amount of butane in the LPG.

A method for starting an engine is provided. The method comprises opening a throttle valve controlling air flow into an intake manifold in response to a gaseous pressure differential across a gaseous fuel injector exceeding a threshold pressure. In this way, delayed engine starts using gaseous fuel may be mitigated.

A natural gas system for an intake manifold of a dual fuel engine is provided. The natural gas system includes a heat exchanger configured to exchange heat with a first stream of natural gas passing therethrough. The natural gas system further includes a temperature regulating assembly positioned downstream of the heat exchanger with respect to the first stream of the natural gas. The temperature regulating assembly includes a conduit having an inlet and an outlet. The temperature regulating assembly also includes a supply line in selective fluid communication with the conduit. The temperature regulating assembly further includes a temperature sensing assembly provided within the conduit. Further, the introduction of the second stream is based on a temperature of the natural gas within the conduit.

A system for method for emptying a gas storage tank of a vehicle is presented. In one example, engine valve timing is adjusted to facilitate reducing pressure within the gas storage tank. The system and method may extend the use of the gas stored in the gas storage tank.

A method for controlling fuel pressure in an internal combustion engine consuming a gaseous fuel and a liquid fuel comprises steps of determining a gaseous fuel pressure target value as a function of an engine operating condition, pressurizing the liquid fuel to a liquid fuel pressure based on the gaseous fuel pressure target value, and regulating gaseous fuel pressure from the liquid fuel pressure. The gaseous fuel pressure equals the gaseous fuel pressure target value to within a predetermined range of tolerance. A corresponding system controls fuel pressure in a gaseous fuelled internal combustion engine.