Selective cylinder deactivation apparatus and method for high power diesel engines

摘要

Various embodiments relate to a method of operating an engine system with injectors having nozzle sac volume. The engine system may be a four-stroke, high power engine having a high-pressure common-rail injection system. A number of engine cylinders to fire is selected based on a fuel injection quantity per selected engine cylinder such that a nitrogen oxides (NOx) emission is less than a first predetermined threshold and a smoke value is less than a second predetermined threshold. The fuel injection quantity per cylinder may be higher than a nominal fuel injection quantity to improve fuel injector spray characteristics. The exhaust can be mixed with fresh air blowout from deactivated cylinders to further reduce smoke value. The engine system is operated with a firing pattern for the selected number of cylinders to fire.

主权项

1. A method of operating an engine system, comprising:
detecting one or more engine system parameters, wherein the one or more parameters include at least one of an engine load and an engine speed; selecting a number of engine cylinders to fire and a fuel injection quantity per selected engine cylinder in response to the one or more engine system parameters such that a nitrogen oxides (NOx) emission is less than a first predetermined threshold and a smoke value is less than a second predetermined threshold, wherein selecting the number of engine cylinders to fire and the fuel injection quantity comprises:
determining a requested engine power;calculating an estimated NOx emission and an estimated smoke value;determining the first and second thresholds;determining available numbers of cylinders to fire;determining acceptable cylinder operating points based on the estimated NOx emission, estimated smoke value, first and second thresholds, and available firing patterns; andselecting a cylinder operating point and corresponding number of cylinders to fire and fuel injection quantity to meet the requested engine power; and operating the engine system with the selected number of engine cylinders to fire at the fuel injection quantity per selected engine cylinder.