Exhaust gas recirculation system with control of EGR gas temperature
AssigneeSouthwest Research Institute
InventorsMagdi Khair, Yiqun Huang, Christopher Sharp, Cynthia Webb
Life of this patent
Estimating the term…
Abstract
A method and system for controlling the temperature of recirculated exhaust gas in an exhaust gas recirculation (EGR) system, such as those used in connection with diesel engines. An EGR loop (which may be either a high pressure loop or a low pressure loop) has a dual-leg segment with an EGR cooler on one leg and an EGR heater on the other leg. By means of a valve, the EGR gas may be diverted to either one leg or the other, thereby providing either cooled or heated EGR gas to the engine.
Claims21
A high-pressure loop exhaust gas recirculation (EGR) system for recirculating exhaust from an engine, the engine having an air intake line, a turbocharger, and a primary exhaust line, comprising:
- an EGR loop for carrying EGR gas, the loop branching from the primary exhaust line upstream the turbine of the turbocharger and entering the engine air intake line downstream the compressor of the turbocharger;
- a dual-leg segment of the EGR loop, a first leg having an EGR cooler and a second leg having an EGR heater;
- and
- a diverter valve at the input to the dual-leg segment, the diverter valve operable to control the amount of EGR flow through the first leg relative to the second leg;
- wherein, downstream the cooler and the heater, the first leg and the second leg are rejoined to a single flow in the EGR loop.
A low pressure loop exhaust gas recirculation (EGR) system for recirculating exhaust from an engine, the engine having an air intake line, a turbocharger, and a primary exhaust line, comprising:
- an EGR loop for carrying EGR gas, the loop branching from the primary exhaust line downstream the turbine of the turbocharger and entering the engine air intake line upstream the compressor of the turbocharger;
- a dual-leg segment of the EGR loop, a first leg having an EGR cooler and a second leg having an EGR heater;
- and
- a diverter valve at the input to the dual-leg segment, the diverter valve operable to control the amount of EGR flow through the first leg relative to the second leg;
- wherein, downstream the cooler and the heater, the first leg and the second leg are rejoined to a single flow in the EGR loop.
A method of controlling the temperature of recirculated exhaust gas in an exhaust gas recirculation (EGR) system of an engine having an air intake line, a turbocharger, and a primary exhaust line, the method comprising:
- recirculating exhaust gas via an EGR loop, the loop branching from the primary exhaust line and entering the engine air intake line;
- wherein the loop has a dual-leg segment, with a first leg having an EGR cooler and a second leg having a EGR heater;
- and
- using a diverter valve at the input to the dual-leg segment to control the amount of EGR flow through the first leg relative to the second leg.
Dependencies are inferred from the claim text.