Electronic engine control for a motor vehicle

• US 5,048,479 A
• Filed: 08/03/1990
• Issued: 09/17/1991
• Est. Priority Date: 08/04/1989
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Bartke, Ralf-Michael
• Primary Examiner(s): Kamen, Noah P.
• Application Number:
  US07/563,093
• Time in Patent Office: 410 Days
• Field of Search: 123/198 D, 123/198 DB, 123/490, 123/497, 123/498, 123/499, 73/118.1, 73/119 R, 324/418, 324/422, 340/439
• US Class Current: 123/198.00D
• CPC Class Codes: F02D 35/0007 using electrical feedback F02D35/0015 takes precedence
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The invention relates to an electronic engine control (EEC) equipped with a fuel cutoff safety device in the form of a relay 12 for controlling the winding of the fuel pump 16. A single conductor (FCOM) connects the fuel pump power supply line with the EEC in order to test and/or monitor the voltage applied across the terminals of the fuel pump, at least when the engine is started up.

Claims

1. In a motor vehicle equipped with an internal combustion engine having an electric fuel pump for supplying fuel to the engine, the fuel pump having terminals for receiving electrical energy for operating the pump, a method for testing a safety device provided for switching off the fuel supply to the engine when there is a fault condition, said safety device including a switching unit switchable for interrupting the supply of electrical energy to the pump, the method comprising the steps of:

supplying the electrical energy from a power supply to said fuel pump at said terminals across which a voltage is present when said electrical energy is supplied and across which a reaction voltage develops when the electrical energy supplied to said terminals is interrupted;

causing an electronic engine control unit to simulate a fault condition by applying a drive signal to said switching unit for switching said switching unit to interrupt the electrical energy to said terminals; and

,

transmitting said reaction voltage to said electronic control unit thereby indicating proper operation of said switching unit or a malfunction of said switching unit when said reaction voltage is not transmitted to said electronic engine control unit in response to said drive signal applied to said switching unit.

2. The method of claim 1, wherein said drive signal is a voltage applied temporarily to said switching unit and said reaction voltage across said terminals is detected and the reaction of said switching unit is correct when the reaction voltage occurs in a predetermined time period after applying said drive signal.

3. The method of claim 1, wherein said drive signal is generated during the start of the engine, before commencing a journey.

4. The method of claim 1, wherein said drive signal is generated for a time period, which is not longer than about 2 seconds.

5. In a motor vehicle equipped with an internal combustion engine having a fuel pump for supplying fuel to the engine, an arrangement for testing a safety device for switching off the fuel supply to the engine when there is a fault condition, the arrangement comprising:

said fuel pump being an electric fuel pump for pumping the fuel to the engine and having terminals for receiving electrical energy for operating the fuel pump;

power supply means for supplying the electrical energy to said fuel pump at said terminals across which a voltage is present when said electrical energy is supplied and across which a reaction voltage develops when the electrical energy supplied to said terminals is interrupted;

said safety device including switching means switchable between a first condition wherein said terminals are connected to said power supply means and a second condition wherein the supply of electrical energy to said terminals is interrupted producing said reaction voltage;

an electronic engine control unit for simulating a fault condition by applying a drive signal to said switching means for switching said switching means into said second condition; and

circuit means for transmitting said reaction voltage to said electronic engine control unit thereby indicating proper operation of said switching means or a malfunction of said switching means when said reaction voltage is not transmitted to said control unit when said drive signal is applied to said switching means.

6. The arrangement of claim 5, said circuit means including a single conductor connecting at least one of said terminals to said electronic engine control unit.

7. The arrangement of claim 5, said switching means being a relay having electrical contacts for applying and interrupting the flow of said electrical energy to said terminals of said electric fuel pump.

8. An electronic engine control (EEC) arrangement for a motor vehicle equipped with an internal combustion engine, the arrangement comprising:

an electronic engine control unit;

an electric fuel pump for pumping fuel to the engine and having terminals for receiving electrical energy for operating the fuel pump;

power supply means for supplying the electrical energy to said fuel pump at said terminals across which a voltage is present when said electrical energy is supplied;

safety means for detecting a fault and cutting off said electrical energy to said fuel pump in response to said fault;

detecting means for detecting said voltage at said terminals and feeding the same back to said electronic engine control unit; and

,

the electronic engine control unit having a speed-dependent safety device which is blocked during ignition, the voltage being detected on an ignition and, if a correct voltage is not detected, the electronic engine control being prevented from taking over control of the pump.

9. A method for controlling and monitoring an internal combustion engine of a motor vehicle, by an electronic engine control system equipped with safety means for cutting off the fuel supply in the event of a fault, the method comprising the steps of:

generating temporarily a signal for activating said safety means;

detecting whether said safety means reacts correctly with said safety means cutting off the power supply of a fuel pump in the event of the fault with a reaction voltage developing when said power supply thereto is cut off; and

,

the reaction voltage, detected by the electronic control system, being the voltage of the fuel pump of the motor vehicle.