Vehicle supplemental heating system including spool valve manifold

A heating apparatus connectable to an engine cooling system of a vehicle, the cooling system including a cooling fluid and a heat exchanger for transferring heat from the cooling fluid to an airstream for heating a passenger compartment of the vehicle, the heating apparatus comprising:

• a liquid heat generator fluidly connected to the engine cooling system, the liquid heat generator having a hydrodynamic chamber operable for selectively heating the cooling fluid present within the hydrodynamic chamber, and an inlet passage fluidly connected to the hydrodynamic chamber;
• a manifold comprising a cavity fluidly connectable to an inlet passage, a first discharge passage, and a second discharge passage, the inlet passage of the manifold fluidly connectable to a discharge passage of the heat exchanger, the first discharge passage of the manifold fluidly connectable to the engine cooling system, and the second discharge passage of the manifold fluidly connected to the inlet passage of the hydrodynamic chamber;
• and
• a control valve comprising a spool slideably disposed within the manifold cavity, the spool moveable between a first position for establishing a fluid path between the manifold inlet passage and the first manifold discharge passage, and a second position for establishing a fluid path between the manifold inlet passage and the manifold second discharge passage.