Systems and methods for controlling cooling fluid temperature in a fuel cell engine

A temperature control system for a vehicular cooling fluid system, the system comprising:

• a supply line configured to carry system cooling fluid at a first temperature;
• a primary heat exchanger in fluid communication with the supply line, the primary heat exchanger configured to receive at least some of the cooling fluid at the first temperature and to discharge cooling fluid at a second temperature that is lower than the first temperature;
• a first device in fluid communication with the primary heat exchanger and configured to receive at least some of the cooling fluid which is at said second temperature;
• a mixing valve having at least two input ports and at least one output port, a first input port being in fluid communication with the heat exchanger to controllably receive therefrom at least some of the cooling fluid which is at said second temperature, a second input port being in fluid communication with the supply line to controllably receive therefrom at least some of the cooling fluid which is at said first temperature, the mixing valve being controllable to mix the cooling fluids which are at said first and second temperatures, to output cooling fluid at a third temperature that is higher than the second temperature and lower than the first temperature;
• and
• a second device located downstream from the mixing valve for receiving the cooling fluid which is at said third temperature from the mixing valve.

Temperature control apparatus for a vehicular cooling fluid system, the temperature control means comprising:

• a supply means for introducing cooling fluid at a first temperature;
• a primary cooling means for receiving the cooling fluid therein at the first temperature and discharging the cooling fluid at a second temperature for use by a first device;
• a first diverter means for diverting at least some of the first temperature fluid from the supply means;
• a second diverter means for diverting at least some of the second temperature fluid from the discharge of the primary cooling means;
• and
• a mixing means for controllably mixing the first temperature fluid received from the first diverter means and the second temperature fluid received from the second diverter means to produce cooling fluid at a third temperature for use by a second device, the third temperature fluid being of a temperature higher than the second temperature and lower than the first temperature.

A temperature control method for a vehicular cooling fluid system, the method comprising:

• supplying a first portion of a cooling fluid having a first temperature from a supply line to a primary heat exchanger and diverting a second portion of the first temperature fluid to a mixing valve;
• cooling the first portion of the fluid to a second temperature within the primary heat exchanger;
• supplying a first portion of the second temperature fluid to a first device and diverting a second portion of the second temperature fluid to a mixing valve;
• controllably mixing second portions of the first and second temperature fluids within the mixing valve to produce a third temperature fluid, the third temperature fluid being of a higher temperature than the second temperature fluid and of a lower temperature than the first temperature fluid;
• and
• supplying the third temperature fluid to a second device.