Exhaust back pressure sensor using absolute micromachined pressure sense die

An exhaust back pressure sensing system, comprising:

• an absolute pressure sensor exposable to an exhaust gas, wherein said absolute pressure sensor comprises at least one pressure sense die micromachined from silicon and a hermetically sealed cover located above a diaphragm configured from said at least one pressure sense die, wherein said sealed cover and said diaphragm form a reference pressure cavity therebetween;
• a housing in which said absolute pressure sensor is located in association with a carrier for maintaining said absolute pressure sensor and a flexible Printed Circuit Board (PCB) populated with a plurality of surface mounted components for electrical connection to said absolute pressure sensor;
• an ASIC connected to said PCB and which communicates electrically with said absolute pressure sensor;
• an EEPROM for calibrating said ASIC;
• a plurality of piezoresistors embedded in said diaphragm at locations that maximize an output of said absolute pressure sensor;
• and
• a pressure inlet formed from said carrier, wherein said pressure inlet is filled with a gel for protecting said diaphragm and at least one adhesive thereof, thereby preventing said exhaust gas, including acids and hazardous chemicals thereof from damaging said at least one pressure sense die and electrically sensitive portions thereof.

An exhaust back pressure sensing method, comprising the steps of:

• micromachining at least one pressure sense die from silicon;
• providing an absolute pressure sensor exposable to an exhaust gas that comprises said at least one pressure sense die and a hermetically sealed cover located above a diaphragm configured from said at least one pressure sense die, wherein said sealed cover and said diaphragm form a reference pressure cavity therebetween;
• locating said absolute pressure sensor in a housing in association with a carrier for maintaining said absolute pressure sensor and a Printed Circuit Board (PCB) populated with a plurality of surface mounted components for electrical connection to said absolute pressure sensor;
• and
• forming a pressure inlet from said carrier, wherein said pressure inlet is filled with a gel for protecting said diaphragm and at least one adhesive thereof, thereby preventing said exhaust gas, including acids and hazardous chemicals thereof from damaging said at least one pressure sense die and electrically sensitive portions thereof.