Power supply control system for an electrically heated catalytic converter

• US 5,966,931 A
• Filed: 09/10/1997
• Issued: 10/19/1999
• Est. Priority Date: 09/18/1996
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Hibino, Masahiko, Sakurai, Kazuhiro, Yoshizaki, Kouji
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): TRAN, BINH Q
• Application Number:
  US08/926,802
• Time in Patent Office: 769 Days
• Field of Search: 60/284, 60/300, 60/286, 60/276, 60/303
• US Class Current: 60/284
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 3/2026 directly electrifying the catalyst substrate, i.e. heating the electrically conductive catalyst substrate by joule effect
• CPC Class Codes: F01N 9/00 Electrical control of exhaust gas treating apparatus monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In the power supply control system, an electrically heated catalytic converter (EHC) is connected to an alternator output terminal via a switch SW1, and a battery is connected to the alternator via a switch SW2 in parallel with the EHC. A control unit (ECU) for controlling the operation of the switches SW1 and SW2 is provided. When the engine has started, the ECU turns on the SW1 and turns off the SW2 to supply electric power to the EHC directly from the alternator. After the EHC is heated to the activating temperature and starts its catalytic action, the ECU turns on both the switches SW1 and SW2 to supply electric power to the EHC from the battery to maintain the temperature of the EHC. Since the electric power for raising the temperature of the EHC is supplied in the condition where the battery is disconnected from the alternator, the output voltage can be increased to a value higher than a normal output voltage for charging the battery. Therefore, a relatively large electric power can be supplied to the EHC without imposing an excessive load on the battery.

Claims

1. A power supply control system for an electrically heated catalytic converter comprising:

an electric generator driven by an internal combustion engine;

a battery;

an electric heater for heating a catalytic converter disposed in an exhaust gas passage of the engine;

a battery charging circuit which connects the battery with the generator and supplies an electric current for charging the battery;

a catalyst heating circuit which directly connects the heater with the generator and supplies an electric current from the generator to the heater in order to raise the temperature of the catalytic converter to an activating temperature of catalysts in the catalytic converter;

a temperature maintaining circuit which connects the heater with the battery and supplies an electric current from the battery to the heater in order to maintain the catalytic converter at the temperature higher than the activating temperature;

first power supply control means for cutting off the battery charging circuit and the temperature maintaining circuit and closing the catalyst heating circuit when the engine has started, thereby heating the catalytic converter to the activating temperature; and

second power supply control means for cutting off the catalyst heating circuit and closing the battery charging circuit and the temperature maintaining circuit when the temperature of the catalysts has reached the activating temperature, thereby charging the battery and, simultaneously, maintaining the catalytic converter at the temperature higher than the activating temperature.

2. A power supply control system for an electrically heated catalytic converter comprising:

an electric generator driven by an internal combustion engine;

an electric heater for heating a catalytic converter disposed in an exhaust gas passage of the engine;

a battery connected to the generator;

a catalyst heating circuit which connects the heater with the battery and supplies an electric current from the battery to the heater in order to raise the temperature of the catalytic converter to an activating temperature of catalysts in the catalytic converter;

a temperature maintaining circuit which connects the heater with a neutral point of the windings of the generator and supplies an electric current from the neutral point to the heater in order to maintain the catalytic converter at the temperature higher than the activating temperature;

first power supply control means for cutting off the temperature maintaining circuit and closing the catalyst heating circuit when the engine has started, thereby, heating the catalytic converter to the activating temperature; and

second power supply control means for cutting off the catalyst heating circuit and closing the temperature maintaining circuit when the temperature of the catalysts has reached the activating temperature, thereby maintaining the catalytic converter at the temperature higher than the activating temperature.