US Patent 8656715 Methods and systems for emission system control

Methods and systems are provided for operating a turbocharged engine including a particulate filter positioned upstream of a turbocharger turbine, a catalyst positioned downstream of the turbine, and an EGR passage coupled between an engine exhaust and engine intake. In one example, the method comprises, diverting exhaust gas from downstream of the filter to the engine intake via the EGR passage, and adjusting an amount of diverted exhaust gas based on filter operating conditions.