External prewarmer for vehicle engine - uses liquid fuelled engine independent heater to also warm vehicle interior

摘要

A thermostat is fitted between the engine and the heater unit, a T-piece is fitted before the heat exchanger, and in addition a bypass passage is so fitted between the thermostat and the T-piece that the heater unit forms its own circuit with the bypass whilst the thermostat is closed. A mass of water is heated in the heater unit, and, after the water has reached a minimum temp. of 60 deg., the thermostat opens and the water is circulated to the vehicle interior heat exchanger and the engine coolant circuit by a pump within the heater unit.