Systems and methods for controlling operation of hybrid vehicles

A hybrid vehicle, comprising:

• an engine;
• an energy storage device;
• an aftertreatment system fluidly coupled to the engine and configured to receive an exhaust gas generated by the engine, the aftertreatment system comprising a selective catalytic reduction (SCR) catalyst configured to treat constituents of the exhaust gas;
• and
• a controller operatively coupled to the engine, the energy storage device, and the aftertreatment system, the controller configured to:
• estimate an exhaust gas temperature and an exhaust gas flow rate of the exhaust gas based on a set of engine operating parameters,
• estimate an exhaust gas cooling rate of the SCR catalyst based on the estimated exhaust gas temperature and the exhaust gas flow rate, and a SCR catalyst temperature,
• determine an ambient cooling rate of the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and the SCR catalyst temperature,
• estimate a SCR catalyst temperature change rate based on the exhaust gas cooling rate and the ambient cooling rate, wherein the SCR catalyst temperature change rate is a change in the SCR catalyst temperature over time, and
• adjust a load distribution between the engine and the energy storage device based on the SCR catalyst temperature change rate.

A method for controlling operation of a hybrid vehicle that includes an engine, an aftertreatment system comprising a selective catalytic reduction (SCR) catalyst coupled to the engine, and an energy storage device, the method comprising:

• estimating, by a controller of the hybrid vehicle, an exhaust gas temperature and an exhaust gas flow rate of an exhaust gas received by the aftertreatment system from the engine based on a set of engine operating parameters;
• estimating, by the controller, an exhaust gas cooling rate of the SCR catalyst based on the estimated exhaust gas temperature, the exhaust gas flow rate, and a SCR catalyst temperature;
• determining, by the controller, an ambient cooling rate of the SCR catalyst based on an ambient temperature of an environment external to the aftertreatment system, a vehicle speed of the hybrid vehicle, and the SCR catalyst temperature;
• estimating, by the controller, a SCR catalyst temperature change rate based on the exhaust gas cooling rate and the ambient cooling rate, wherein the SCR catalyst temperature change rate is a change in the SCR catalyst temperature over time;
• and
• adjusting, by the controller, a load distribution between the engine and the energy storage device based on the SCR catalyst temperature change rate.

A controller for controlling an operation of a hybrid vehicle that includes an engine, an aftertreatment system comprising a selective catalytic reduction (SCR) catalyst coupled to the engine, and an energy storage device, the controller being configured to be operatively coupled to the engine, the energy storage device, and the aftertreatment system, the controller configured to:

• estimate an exhaust gas cooling rate of the SCR catalyst;
• determine or estimate an ambient cooling rate of the SCR catalyst;
• estimate a SCR catalyst temperature change rate based on the exhaust gas cooling rate and the ambient cooling rate, wherein the SCR catalyst temperature change rate is a change in the SCR catalyst temperature over time;
• and
• adjust a load distribution between the engine and the energy storage device based on the SCR catalyst temperature change rate.