US-12618353-B1 - Low resistance exhaust system with correction module for regeneration control

US12618353B1US 12618353 B1US12618353 B1US 12618353B1US-12618353-B1

Abstract

A low resistance exhaust system with regeneration control includes a correction module. The correction module is programmed and operable to receive pressure signals from a sensor assembly measuring pressure across an exhaust particulate filter, and to compute a corrected pressure signal to send to the vehicle engine control module (ECM). The corrected pressure signal allows the ECM to properly evaluate the pressure signals arising from the use of a low resistance aftermarket exhaust outlet tube. This allows the ECM to accurately execute regeneration actions to properly manage soot buildup in the exhaust particulate filter despite being calibrated for the OEM/stock exhaust outlet tube, and to avoid triggering DTCs.

Inventors

Gale C. Banks, III
Quinn Alexander Smith

Dates

Publication Date: 20260505
Application Date: 20251009

Claims (20)

1 . A low resistance exhaust system for enhancing the performance of an internal combustion engine of a vehicle comprising an Original Equipment Manufacturer (OEM) exhaust system, wherein the OEM exhaust system comprises a first exhaust outlet tube comprising a first exhaust tip open to atmosphere, an exhaust particulate filter (EPF) upstream of said first exhaust outlet tube, and a sensor assembly operable to measure pressure across the EPF, the low resistance exhaust system comprising: a second exhaust outlet tube adapted to couple to the EPF in place of the first exhaust outlet tube comprising a second exhaust tip open to atmosphere and having a lower flow resistance than the first exhaust outlet tube; and a correction module comprising at least one processor, memory, and signal generator, and wherein the correction module is configured to: receive at least one raw pressure signal from the sensor assembly representative of the pressure across the EPF in the flow path associated with the second exhaust outlet tube, and to compute and generate a corrected pressure signal corresponding to the at least one raw pressure signal received from the pressure sensor assembly by applying signal modification logic defined for operation with the second exhaust outlet tube; and to send the corrected pressure signal to a vehicle engine control module (ECM); and wherein the vehicle ECM is tuned to interpret pressure signals arising from the sensor assembly across the EPF in the flow path associated with the first exhaust outlet tube; and to evaluate the pressure signals to determine a regeneration action to mitigate soot buildup.
2 . The system of claim 1 , further comprising the EPF, and wherein the EPF is optionally a diesel particulate filter.
3 . The system of claim 1 , wherein the second exhaust outlet tube comprises at least one characteristic which causes the flow resistance of the second exhaust outlet tube to be lower than the first exhaust outlet tube, and wherein the at least one characteristic is selected from size and shape.
4 . The system of claim 1 , wherein the signal modification logic of the correction module comprises a trained machine learning model to calculate the corrected pressure signal.
5 . The system of claim 1 , wherein the signal modification logic of the correction module comprises a lookup table to produce the corrected pressure signal.
6 . The system of claim 1 , wherein the signal modification logic of the correction module comprises a non-linear equation to calculate the corrected pressure signal.
7 . The system of claim 1 , further comprising the ECM, and wherein the regeneration action is an active regeneration comprising one or more of the following: alter the combustion air/fuel ratio, inject fuel into the exhaust stream, or activate a heater to raise exhaust gas temperatures to burn off the soot buildup in the EPF.
8 . The system of claim 1 , further comprising an exhaust inlet tube, wherein the EPF is arranged between the exhaust inlet tube and the exhaust outlet tube.
9 . The system of claim 1 , wherein the correction module is further operable to filter the at least one raw pressure signal received from the sensor assembly to remove anomalies.
10 . The system of claim 1 , further comprising the sensor assembly.
11 . The system of claim 10 , wherein the pressure assembly is a differential pressure sensor (DPS).
12 . A correction module for use with a vehicle having an internal combustion engine, the correction module comprising: a signal generator; at least one processor and memory configured to receive at least one raw pressure signal representative of the pressure across an exhaust particulate filter (EPF) in a flow path associated with a second exhaust tube; wherein the second exhaust tube has a lower flow resistance than a first exhaust outlet tube, and to compute and generate a corrected pressure signal corresponding to the at least one raw pressure signal received from the pressure sensor assembly by applying signal modification logic defined for operation with the second exhaust outlet tube, and to send the corrected pressure signal to a vehicle engine control module (ECM); and wherein the vehicle ECM is tuned to interpret pressure signals arising from the sensor assembly across the EPF in the flow path associated with the first exhaust tube; and to evaluate the pressure signals for a regeneration action to mitigate soot buildup.
13 . The correction module of claim 12 , wherein the signal modification logic is configured to apply a lookup table to produce the corrected pressure signal.
14 . The correction module of claim 13 , further operable to filter the at least one raw pressure signal received from the sensor assembly to remove anomalies.
15 . A method for conditioning a pressure signal from a differential pressure sensor (DPS) in an exhaust system of a vehicle having an internal combustion engine, wherein the DPS measures pressure across an exhaust particulate filter (EPF) of an aftermarket exhaust outlet tube having a lower flow resistance than an original equipment manufacturer (OEM) exhaust outlet tube, the method comprising: sending a raw pressure signal from the DPS to a correction module comprising at least one processor, memory, and a signal generator; generating, by the correction module, a corrected pressure signal to send to an OEM-calibrated engine control module (ECM); wherein the signal generator, at least one processor and memory are configured to transform the raw pressure signal into the corrected pressure signal based on at least one dataset previously mapping DPS pressures for the OEM exhaust outlet tube and the aftermarket exhaust outlet tube based on soot load; and sending the corrected pressure signal to the OEM-calibrated ECM.
16 . The method of claim 15 , wherein the correction module is configured to transform the raw pressure signal into the corrected pressure signal based on a lookup table.
17 . The method of claim 15 , further comprising filtering the at least one raw pressure signal received from the DPS to remove anomalies.
18 . The method of claim 15 , further comprising performing a regeneration action comprising one or more of the following: alter the combustion air/fuel ratio, inject fuel into the exhaust stream, or activate a heater to raise exhaust gas temperatures to burn off the soot buildup in the EPF.
19 . The correction module of claim 12 , wherein the sensor assembly is a differential pressure sensor (DPS).
20 . The correction module of claim 12 , further comprising compensation diagnostics, optionally a PID controller, operable to monitor for output errors or signal drift to maintain accuracy.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS None. FIELD OF THE INVENTION The field of the present invention is exhaust systems for combustion engines, and more particularly, exhaust systems for vehicle combustion engines. BACKGROUND Current vehicle exhaust emissions systems include exhaust particulate filters (EPF), which may be either a diesel particulate filter (DPF) or a gasoline particulate filter (GPF) according to the engine fuel type. These systems employ ceramic honeycomb structures (typically cordierite or silicon carbide) placed in the exhaust flow to trap particulate matter (PM) including fine PM2.5 carbon nanoparticles (soot) produced by the combustion process. As the exhaust gasses pass through the porous walls of the filter 85 to 100% of the soot is trapped and the cleaner gasses are allowed to exit. The soot trapped by the EPF accumulates over time, and if left unmanaged may clog the filter and increase backpressure, potentially harming engine performance. The amount of soot resident in the EPF is monitored by the engine control module (ECM) and is commonly referred to as the soot load and expressed as a percentage of total capacity. Management of the soot load is typically accomplished through a process, referred to as regeneration, in which the EPF is heated to a temperature sufficient to combust the trapped soot, converting it into less harmful gasses like carbon dioxide. Regeneration may occur without outside intervention when operating the vehicle in a manner such that exhaust gas temperature is sufficiently high as to burn off soot from the EPF. This typically occurs during highway driving and is referred to as passive regeneration. When passive regeneration is not able to adequately reduce soot load the ECM will intervene in a process referred to as active regeneration. During active regeneration the ECM may alter the combustion air/fuel ratio, inject fuel into the exhaust stream, or use a heater to raise exhaust gas temperatures (often to 600° C. or higher) to burn off the soot. After regeneration, a small amount of incombustible ash (from engine oil additives or fuel impurities) remains in the filter. Over hundreds of thousands of miles this ash can accumulate, requiring the filter to be professionally cleaned or replaced. In order to track the condition of the system the ECM typically monitors the difference in exhaust pressure between the inlet and outlet of the EPF as a measurement of soot load percentage. As soot accumulates within the exhaust particulate filter (EPF), it gradually reduces the available flow area for exhaust gases. Consequently, as the soot load percentage increases, the pressure drop from the inlet to the outlet rises proportionally, due to the increasing restriction to gas flow. This measurement is commonly taken by a differential pressure sensor (DPS) which measures the pressure drop (AP) across the filter via two ports connected by tubes to the EPF inlet and outlet. A diaphragm or piezoelectric element inside converts AP into a voltage, frequency, or digital signal which is provided to the ECM to calculate soot load. Alternatively, this measurement may be taken by two discrete pressure sensing elements. The difference in their reported values is then calculated either by the vehicle ECM or within an integrated module. The DPS signal is used for triggering active regeneration, tracking ash, and preventing clogs that could elevate backpressure and set diagnostic trouble codes (DTCs), trigger a power de-rate, or put the vehicle in a limp home mode. Statement of Problem When an enhanced exhaust system with reduced flow restriction is introduced downstream of the EPF, the pressure at the EPF outlet may be significantly reduced. This is commonly referred to as a reduction in backpressure. This backpressure reduction is propagated throughout the entire exhaust system and to the engine's piston(s), which resultingly expend less work on the exhaust stroke pumping exhaust gasses out of the cylinder(s). This reduction of parasitic load on the engine both adds to the maximum power output of the engine and reduces the amount of fuel required when compared at the same power output. This effect is even more meaningful in turbocharged engines wherein parasitic losses to pumping are considerably larger in magnitude, and the turbine expansion ratio can cause a backpressure reduction at the tailpipe to be tripled or quadrupled at the piston(s). These positive effects are prevented in modern vehicles because the DPS and ECM are calibrated to the original manufacturers more restrictive exhaust assemblies. While reduced restriction exhaust systems provide for a decreased exhaust backpressure that propagates through the entire exhaust system, the backpressure reduction at the EPF outlet is commonly larger in magnitude than at the EPF inlet, thus increasing the magnitude of the DPS reading. The ECM is unable to compensate for the change to the downstream exhaust system and, as a result,