Internal combustion engine system and method for reduced turbo lag

Method for operating an internal combustion engine system comprising:

• an internal combustion engine provided with at least one cylinder;
• a turbocharger arrangement comprising a turbocharger turbine operatively connected to a turbocharger compressor;
• an air intake system arranged to feed intake air via the turbocharger compressor to the at least one cylinder;
• an exhaust gas system arranged to feed exhaust gas away from the at least one cylinder and to feed exhaust gas via the turbocharger turbine so as to drive the turbocharger compressor;
• an exhaust gas recirculation (EGR) conduit arranged between a point upstream the turbocharger turbine of the exhaust gas system and a point downstream the turbocharger compressor of the air intake system so as to allow recirculation of high pressure exhaust gas from the exhaust gas system to the air intake system;
• an EGR valve arranged in the EGR conduit so as to provide for regulation of a flow of the high pressure exhaust gas through the EGR conduit;
• and
• a turbomachine configured to provide for a forced flow of gas in the internal combustion engine system,
• wherein the turbomachine is arranged in the EGR conduit so as to allow for a forced flow of gas through the EGR conduit,
• wherein the EGR valve and the turbomachine are positioned in relation to each other in the EGR conduit such that a flow of high pressure exhaust gas through the EGR conduit towards the air intake system reaches the EGR valve before reaching the turbomachine,
• wherein an additional exhaust gas conduit is arranged between the EGR conduit and a point of the exhaust system downstream the turbocharger turbine so as to allow exhaust gas to flow between the EGR conduit and the point downstream the turbocharger turbine without passing through the turbocharger turbine, wherein the additional exhaust gas conduit is connected to the EGR conduit at a point between the EGR valve and the turbomachine so as to provide a communication between the turbomachine and the additional exhaust gas conduit even if the EGR valve is closed,
• wherein an additional exhaust valve is arranged in connection with the additional exhaust gas conduit so as to provide for regulation of a flow of gas through the additional exhaust gas conduit, and
• wherein the internal combustion engine system is provided with an exhaust gas aftertreament system (EATS) arranged downstream the turbocharger turbine and downstream also the additional exhaust gas conduit,
• the method comprising;
• closing the EGR valve so as to restrict a flow of recirculated high pressure exhaust gas through the EGR conduit;
• opening the additional exhaust valve so as to allow exhaust gas to flow through the additional exhaust gas conduit into the EGR conduit;
• and
• operating the turbomachine so as to force exhaust gas that has passed the turbocharger turbine to flow through the additional exhaust gas conduit and further through the EGR conduit to the air intake system.

A control system comprising circuitry configured to:

• control an internal combustion engine system comprising:
• an internal combustion engine provided with at least one cylinder;
• a turbocharger arrangement comprising a turbocharger turbine operatively connected to a turbocharger compressor;
• an air intake system arranged to feed intake air via the turbocharger compressor to the at least one cylinder;
• an exhaust gas system arranged to feed exhaust gas away from the at least one cylinder and to feed exhaust gas via the turbocharger turbine so as to drive the turbocharger compressor;
• an exhaust gas recirculation (EGR) conduit arranged between a point upstream the turbocharger turbine of the exhaust gas system and a point downstream the turbocharger compressor of the air intake system so as to allow recirculation of high pressure exhaust gas from the exhaust gas system to the air intake system;
• an EGR valve arranged in the EGR conduit so as to provide for regulation of a flow of the high pressure exhaust gas through the EGR conduit;
• and
• a turbomachine configured to provide for a forced flow of gas in the internal combustion engine system,
• wherein the turbomachine is arranged in the EGR conduit so as to allow for a forced flow of gas through the EGR conduit,
• wherein the EGR valve and the turbomachine are positioned in relation to each other in the EGR conduit such that a flow of high pressure exhaust gas through the EGR conduit towards the air intake system reaches the EGR valve before reaching the turbomachine,
• wherein an additional exhaust gas conduit is arranged between the EGR conduit and a point of the exhaust system downstream the turbocharger turbine so as to allow exhaust gas to flow between the EGR conduit and the point downstream the turbocharger turbine without passing through the turbocharger turbine, wherein the additional exhaust gas conduit is connected to the EGR conduit at a point between the EGR valve and the turbomachine so as to provide a communication between the turbomachine and the additional exhaust gas conduit even if the EGR valve is closed,
• wherein an additional exhaust valve is arranged in connection with the additional exhaust gas conduit so as to provide for regulation of a flow of gas through the additional exhaust gas conduit, and
• wherein the internal combustion engine system is provided with an exhaust gas aftertreament system (EATS) arranged downstream the turbocharger turbine and downstream also the additional exhaust gas conduit,
• the circuitry further configured to:
• close the EGR valve so as to restrict a flow of recirculated high pressure exhaust gas through the EGR conduit;
• open the additional exhaust valve so as to allow exhaust gas to flow through the additional exhaust gas conduit into the EGR conduit;
• and
• operate the turbomachine so as to force exhaust gas that has passed the turbocharger turbine to flow through the additional exhaust gas conduit and further through the EGR conduit to the air intake system.