Method of operating a vehicle powertrain having a gas phase fuelable engine

摘要

A method of operating a vehicle powertrain includes determining a selected powertrain operational mode. A demand fraction is determined. An internal combustion engine (ICE) is to output a maximum power when a gaseous fuel is conveyed to an injector of the ICE at a source pressure greater than a cutoff pressure. The source pressure in a container in fluid connection with the injector is determined. The gaseous fuel is received at the source pressure by the injector to inject the gaseous fuel into the ICE for combustion in response to the source pressure, demand fraction, or selected powertrain operation mode meeting a first set of criteria. The injector is prevented from injecting the gaseous fuel into the ICE and the powertrain is driven from an alternative power source in response to the source pressure, demand fraction, or selected powertrain operation mode meeting a second set of criteria.

主权项

1. A method of operating a vehicle powertrain, the method comprising:
determining whether a selected powertrain operational mode is an extended range mode; determining a demand fraction of a maximum powertrain power of the vehicle powertrain, the vehicle powertrain including an internal combustion (IC) engine, the IC engine having a maximum output power when a gas phase fuel is conveyed to a fuel injector of the IC engine at a source pressure greater than a cutoff pressure; determining a gas phase fuel pressure in a fuel container in fluid connection with a fuel rail of the IC engine; operating the powertrain exclusively on the gas phase fuel if:
the pressure in the fuel container is above the cutoff pressure; orthe pressure in the fuel container is between a minimum pressure and the cutoff pressure;the selected powertrain operational mode is the extended range mode; andthe demand fraction is below a predetermined threshold; and operating the powertrain exclusively on a liquid phase fuel or an electric drive motor if:
the pressure in the fuel container is below the minimum pressure; orthe pressure in the fuel container is between the minimum pressure and the cutoff pressure; andthe selected powertrain operational mode is not the extended range mode; orthe demand fraction is greater than or equal to the predetermined threshold wherein the IC engine is a bi-fuel engine having the fuel rail in fluid connection with a fuel tank to contain the liquid phase fuel, or the powertrain includes the electric drive motor powered by a battery.