GB1120119A - Vehicle heating system - Google Patents

Abstract

1,120,119. Heating vehicles. STEWARTWARNER CORP. 17 Aug., 1965 [17 Aug., 1964; 9 March, 1965], No. 3760/68. Divided out of 1,120,118. Heading F4V. In a motor vehicle heating system air supplied to the vehicle cab is normally heated by engine exhaust gases but may be heated instead or in addition by a burner. As illustrated, an enginedriven fan 302 passes air to two chambers 308, 310 which are heated by exhaust gases. According to the setting of valves 316, 318 the air is ejected to atmosphere or passed through a chamber 328 heated by a burner 360 to be supplied to the vehicle cab 342. A motor 354, when energized, powers a fuel pump 357 and an air blower 362 to operate the burner 360, and also powers a blower 352 to supply additional air to the chamber 328 via a duct 356. A valve 358 in the duct 356 opens when the pressure at the outlet of chamber 308 falls to a predetermined level. The system is controlled by a thermostat 344 which comprises a bimetallic helix 374 connected between a spindle 368 and a sleeve 371 surrounding the spindle and carrying two cams 376 and 378 for actuating switches 380 and 382. The spindle carries a cam 366 and its position is determined by the setting of a manual control 373. The heating system is rendered operative by turning the spindle 368 so that cam 366 allows switch 370 to close thereby energizing the motor 354 and a thermal time switch 408 which subsequently causes the power supply to the motor 354 to by-pass the switch 370. Closing the switch 370 also operates a relay 413 to close contacts 417 so that a solenoid valve 415 in the fuel line to the burner is ready for operation. A required air temperature is set by appropriately positioning the spindle 368 and, under the control of the bimetal helix 374 increasing temperature demand is met first by the closing of switch 380 by cam 374 and second by closing of switch 382 by cam 378. Closing of switch 380 actuates a valve 350 in a vacuum line to move valves 316 and 318 so that air heated by exhaust gases passes to the vehicle cab. Closing of switch 382 opens the fuel valve 415 and energizes a burner igniter 488 so that additional heat is provided to the chamber 328. When insufficient air is passed by the fan 302 air will be admitted from the blower 352 and if the vehicle engine is not operating the vehicle will be heated solely by air from the blower 352 which has been heated by the burner 360. The heating system may be energized prior to use of the vehicle by means of a time switch 388 which by-passes the vehicle ignition switch 394. In a modified system, Figs. 4 and 5 (not shown), air from the engine-driven blower may by-pass the exhaust gas heating chambers and the auxiliary motor is actuated by the lower temperature cam on the spindle 371.