Exhaust gas recirculation in internal combustion engines

A method for recirculating exhaust gases produced by an internal combustion engine, the internal combustion engine having an intake manifold and an exhaust manifold, comprising the steps of:

• cooling the exhaust gases in a heat exchanger to produce cooled exhaust gases;
• filtering the cooled exhaust gases by passing them through a filter to produce cooled and filtered exhaust gases;
• drawing from the filter an amount of cooled and filtered exhaust gases to be recirculated;
• and
• directing the cooled and filtered exhaust gases into the intake manifold.

An exhaust gas recirculation system for an internal combustion engine, the internal combustion engine including an intake manifold and an exhaust manifold, comprising:

• a water-cooled heat exchanger having an inlet end and an outlet end, the inlet end of said heat exchanger being connected to the exhaust manifold;
• a filter having an inlet end and an outlet end, the inlet end of said filter being connected to the outlet end of said heat exchanger, the outlet end being connected to the intake manifold;
• an intermittent water injection system connected at about the inlet end of said heat exchanger for injecting a predetermined quantity of water at periodic time intervals into exhaust gases from the engine;
• a first valve having an inlet end and an outlet end, the inlet end being connected to the outlet end of said filter;
• and
• a valve control system connected to said first valve for selectively opening and closing said first valve, wherein cooled and filtered exhaust gases are recirculated into the intake manifold when said first valve is open.

A method for recirculating exhaust gases produced by an internal combustion engine, the internal combustion engine having an intake manifold and an exhaust manifold comprising the steps of:

• drawing from the exhaust manifold only an amount of exhaust gases to be recirculated;
• oxidizing the exhaust gases to be recirculated by passing them over a catalyst;
• cooling the exhaust gases in a heat exchanger;
• filtering the exhaust gases by passing them through a filter;
• and
• directing the exhaust gases into the intake manifold.

An exhaust gas recirculation system for an internal combustion engine, the internal combustion engine including an intake manifold and an exhaust manifold, comprising:

• a first valve having an inlet end and an outlet end, the inlet end being connected to the exhaust manifold;
• a heat exchanger having an inlet end and an outlet end, the inlet end of said heat exchanger being connected to the outlet end of said first valve;
• a filter having an inlet end and an outlet end, the inlet end of said filter being connected to the outlet end of said heat exchanger, and the outlet end being connected to the intake manifold of the engine;
• a valve control system connected to said first valve for selectively opening and closing said first valve, wherein cooled and filtered exhaust gases are recirculated into the intake manifold when said first valve is open;
• an intermittent water injection system connected at about the inlet end of said heat exchanger for injecting a predetermined quantity of water at periodic time intervals into exhaust gases from the engine;
• and
• a catalyst positioned between said first valve and said heat exchanger.

An exhaust gas recirculation system for an internal combustion engine, the internal combustion engine having an intake manifold and an exhaust manifold, comprising:

• a first valve having an inlet and an outlet, the inlet of said first valve being connected to the exhaust manifold of the internal combustion engine;
• a catalyst assembly having an inlet and an outlet, the inlet of said catalyst assembly being connected to the outlet of said first valve;
• a water-cooled heat exchanger having an inlet end and an outlet end, the inlet end of said heat exchanger being connected to the outlet of said catalyst assembly;
• a filter assembly having an inlet end and an outlet end, the inlet end of said filter assembly being connected to the outlet end of said heat exchanger, the outlet end of said filter assembly being connected to the intake manifold of the internal combustion engine;
• a valve control system connected to said first valve for opening and closing said first valve;
• and
• an intermittent water injection system associated with said heat exchanger, the intermittent water injection system having an reservoir for containing a supply of water, an injector mounted at about the inlet end of said heat exchanger, and a pump for pumping a quantity of water from the reservoir to the injector at predetermined intervals.