System and method for controlling a cold light off catalyst
A control system for a vehicle powertrain having a normally aspirated engine includes an advanced device, a main catalyst, a cold light off catalyst (CLOC), a CLOC valve and a controller. The advanced device is positioned in an exhaust of the normally aspirated engine. The main catalyst positioned in the exhaust downstream of the advanced device. The CLOC is positioned in a bypass passage around the advanced device. The CLOC valve selectively routes exhaust flow from the normally aspirated engine between advanced device and the CLOC. The controller is configured to: determine a temperature of a main catalyst; determine, based on a temperature of the main catalyst being less than a temperature threshold, a first engine torque request; and command, based on the first engine torque request being less than a first torque threshold, the CLOC valve to operate in a CLOC mode.
1 . A control system for a vehicle powertrain having a normally aspirated engine, the system comprising:
an advanced device positioned in an exhaust of the normally aspirated engine;
a main catalyst positioned in the exhaust downstream of the advanced device;
a cold light off catalyst (CLOC) positioned in a bypass passage around the advanced device;
a CLOC valve that selectively routes exhaust flow from the normally aspirated engine between advanced device and the CLOC; and
a controller configured to:
determine a temperature of a main catalyst;
determine, based on a temperature of the main catalyst being less than a temperature threshold, a first engine torque request;
command, based on the first engine torque request being less than a first torque threshold, the CLOC valve to operate in a CLOC mode;
operate the CLOC valve in a normal mode based on a temperature of the main catalyst not being less than a temperature threshold, the normal mode corresponding to routing exhaust gas through the advanced device and to the main catalyst;
determine, based on the first engine torque request not being less than a first torque threshold, whether the torque request is greater than a second torque threshold; and
command, based on the torque request being greater than the second torque threshold, the CLOC valve to operate in the normal mode.
2 . The control system of claim 1 , wherein the controller is configured to:
operate, based on the power request not being greater than the second torque threshold, the CLOC valve in a partial CLOC mode.
3 . The control system of claim 1 , wherein the advanced device comprises a waste heat recovery system.
4 . The control system of claim 3 , wherein the waste heat recovery system includes a Rankine cycle waste heat recovery system.
5 . The control system of claim 1 , wherein the advanced device comprises an advanced boosting system.
6 . The control system of claim 1 , wherein the advanced device comprises a thermal recovery system.
7 . The control system of claim 1 , wherein the first torque threshold is indicative of a throttle input of less than 25% of a maximum torque request.
8 . A method of controlling a vehicle powertrain having a normally aspirated engine, the powertrain having an advanced device positioned in an exhaust of the normally aspirated engine, a main catalyst positioned in the exhaust downstream of the advanced device, a cold light off catalyst (CLOC) positioned in a bypass passage around the advanced device, a CLOC valve that selectively routes exhaust flow from the normally aspirated engine between advanced device and the CLOC, and a controller, the method comprising:
determining a temperature of a main catalyst;
determining, based on a temperature of the main catalyst being less than a temperature threshold, a first engine torque request;
commanding, based on the first engine torque request being less than a first torque threshold, the CLOC valve to operate in a CLOC mode;
operating the CLOC valve in a normal mode based on a temperature of the main catalyst not being less than a temperature threshold, the normal mode corresponding to routing exhaust gas through the advanced device and to the main catalyst
determining, based on the first engine torque request not being less than a first torque threshold, whether the torque request is greater than a second torque threshold; and
commanding, based on the torque request being greater than the second torque threshold, the CLOC valve to operate in the normal mode.
9 . The method of claim 8 , further comprising:
operating, based on the power request not being greater than the second torque threshold, the CLOC valve in a partial CLOC mode.
10 . The method of claim 8 , wherein the advanced device comprises a waste heat recovery system.
11 . The method of claim 10 , wherein the waste heat recovery system includes a Rankine cycle waste heat recovery system.
12 . The method of claim 8 , wherein the advanced device comprises an advanced boosting system.
13 . The method of claim 8 , wherein the advanced device comprises a thermal recovery system.
14 . The method of claim 8 , wherein the first torque threshold is indicative of a throttle input of less than 25% of a maximum torque request.