Abstract: A multi-functional exhaust system for diesel and natural gas engines includes a rectangular box housing, a selective catalytic reduction (SCR) unit, at least one reductant injector, a plurality of sensors, and a mixing duct to mix the injected reductant and the exhaust gas. A portion of the mixing duct runs in parallel beside the SCR unit reducing the overall length of the housing. Another portion of the mixing duct routes the exhaust gas through a 180 degree bend to redirect the exhaust gas to the SCR unit. The SCR unit and mixing duct are positioned within the housing and in fluid communication with an inlet and an outlet of the housing. The inlet is in fluid communication with an engine, and the outlet is in fluid communication with an exhaust outlet so that the housing can be secured as the exhaust system.

Abstract: An active control system for diesel particulate filter includes a particulate filter unit, at least one sensor, a control unit, and a bypass unit. The sensor is in fluid communication with the particulate filter unit and electrically connected with the control unit so that the sensor is able to communicate with the control unit regarding the pressure and temperature readings of the exhaust gas flow. The bypass unit is in fluid communication with the particulate filter unit while a control valve of the bypass unit is electrically connected with the control unit. The control unit is able to operate the control valve depending upon the pressure and temperature readings of the sensor so that the bypass unit can be activated for the exhaust gas flow, where the bypass unit decreases the particulate matter buildup within the particulate filter unit and eliminates high engine exhaust back pressure.

Abstract: A pre-heat system for the catalyst of the selective catalytic reduction (SCR) device includes an air blower, an interconnecting pipe, a heater unit, and a heat supply pipe. The air blower and the heater unit are in fluid communication with each other through the interconnecting pipe while the heater unit is in fluid communication with an exhaust system through the heat supply pipe. A hot-air flow generated from the air blower and the heater unit flows into the exhaust system so that the hot-air flow is able to pre-heat the catalyst of the SCR device at or close to an activation temperature. Then the SCR device can efficiently and quickly reduce Nitrogen Oxides (NOx) particles of the exhaust gas.