Heater controller

• US 4,744,747 A
• Filed: 12/23/1986
• Issued: 05/17/1988
• Est. Priority Date: 12/23/1985
• Status: Expired due to Fees

• Current Assignee: Isuzu Motors Limited
• Original Assignee: Isuzu Motors Limited
• Inventors: Yoshida, Yukio, Kawamura, Hideo, Yamashita, Keiichi
• Primary Examiner(s): FOCARINO, MARGARET ANN
• Application Number:
  US06/945,865
• Time in Patent Office: 511 Days
• Field of Search: 431/28, 431/36, 431/41, 431/78, 431/208, 431/258, 431/259, 431/75, 126/350 A, 237/12.3 C, 237/2 A, 123/550, 123/551
• US Class Current: 431/36
• CPC Class Codes: B60H 1/2206 controlling the operation of burners control of burners in general F23N5/00
• CPC Class Codes: B60H 2001/2271 Heat exchangers, burners, ignition devices
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: F23N 2225/16 burner temperature
• CPC Class Codes: F23N 2227/42 Ceramic glow ignition
• CPC Class Codes: F23N 2241/14 Vehicle heating, the heat being derived otherwise than from the propulsion plant
• CPC Class Codes: F23N 5/14 using thermo-sensitive resistors
• CPC Class Codes: F23N 5/203 using electronic means
• CPC Class Codes: G05D 23/1919 characterised by the type of controller
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor

Abstract

A controller for a heater has two switch circuits for controlling the supply of electric power to an atomizing glow plug for atomizing fuel and an ignition glow plug for igniting atomized fuel, the glow plugs being connected parallel to each other. One of the switch circuits includes a series-connected resistor for producing a voltage drop thereacross. During an inital period of operation of the heater, the first switch circuit free of the series-connected resistor is turned on to heat the glow plugs quickly up to respective prescribed temperatures for atomizing and igniting the fuel. Upon elapse of a predetermined period of time, during which the prescribed temperatures are reached, the first switch circuit is turned off and the second switch circuit with the series-connected resistor is turned on to keep the glow plugs at the prescribed temperatures without further heating them.

Claims

1. A controller for controlling a heater including a burner having an atomizing glow plug for heating and atomizing fuel and an igniting glow plug for igniting the fuel which has been heated and atomized by the atomizing glow plug, said controller comprising:

a first switch for supplying electric power to said atomizing glow plug and said igniting glow plug which are connected in parallel with each other;

a second switch connected in parallel with said first switch and in series with a resistor for producing a voltage drop there across;

a combustion sensor for sensing temperature inside said burner; and

means for closing said first switch and, upon elapse of a predetermined period of time, opening said first switch and closing said second switch, and for cutting off supply of electric power to said atomizing glow plug and said igniting glow plug when the temperature inside said burner sensed by said combustion sensor has reached a predetermined value.

2. A controller according to claim 1, further including means for detecting a voltage applied to said atomizing and ignition glow plugs to control said predetermined period of time.

3. A controller according to claim 1, wherein said atomizing glow plug is connected to said first and second switches through an adjusting resistor.

4. A controller according to claim 1, wherein said atomizing glow plug has a heating element made of a ceramics material with a resistance wire of a positive temperature coefficient embedded therein.

5. A controller according to claim 1, wherein said ignition glow plug has a heating element made of a ceramics material with a resistance wire of a positive temperature coefficient embedded therein.