Proportional heater control for diesel emission system for marine powered generator set

摘要

A proportional heater controls a marine diesel powered generator with a diesel particulate filter (DPF). A proportional control is applied to the heater based upon exhaust temperature. The heater heats exhaust gas to a regeneration temperature to remove soot and sulphur from the processed gas when the diesel fuel has a sulphur content exceeding 1,000 ppm. The heater is supplied power via SCRs to reduce electromagnetic and radio frequency interference. A manual override permits the operator to set a temperature setpoint, force the heater to meet a certain temperature and establish a load bank for diesel engine electrical generator set.

主权项

1. A proportional heater control for a marine diesel engine emissions system coupled to a power generator as a diesel generator set wherein a marine diesel engine is motively coupled to an electrical generator, said marine diesel engine having an exhaust system for its exhaust gas and a diesel particulate filter in said exhaust system, said generator set generating three phase AC power, the proportional heater control for marine generator set emissions system comprising:
a plurality of in-line heater elements disposed upstream of said filter in said exhaust system such that exhaust gas continually passes therethrough during engine operation, said heater elements controlled by a heater control signal; an exhaust gas temperature sensor upstream of said filter in said exhaust system; a controller, coupled to said temperature sensor and said heater elements, generating a proportional heater control signal based upon the sensed temperature from said sensor while the diesel engine is applying its exhaust gas to said filter; wherein said heater elements are supplied three phase AC power by said electrical generator and the controller applies proportional three phase AC power to said heater elements via respective silicon controlled rectifiers (SCRs) based upon said exhaust gas temperature and increasing the diesel engine exhaust temperature due to increased engine loading based upon electrical power supplied to said heater elements from said electrical generator; whereby the controlled heater elements maintain exhaust gas temperature not less than a predetermined regeneration exhaust gas temperature during operation of said generator set; and wherein the three-phase AC power from said electrical generator via said controller is delivered to said heating elements through said SCRs which switch AC power to respective heaters elements ON and OFF in proportion to said heater control signals from said exhaust gas temperature sensor in a variable time-based mode wherein power delivered by the SCRs substantially eliminates electrical noise associated with switching high voltages and currents and substantially eliminates harmonics created by variable frequency controllers and power surges caused by switching the generator set to heavy loads ON and OFF.