ENGINE COOLING SYSTEM ONBOARD DIAGNOSTIC STRATEGY
First Claim
1. An engine cooling system diagnostic method, comprising the steps of:
- initiating execution of a cooling system diagnostic algorithm;
recording a coolant temperature for at least one location at a plurality of times as part of execution of the cooling system diagnostic algorithm;
actuating a cooling system electrical actuator intrusively as part of execution of the cooling system diagnostic algorithm when a cooling system controller has the cooling system electrical actuator deactuated;
comparing a first coolant temperature before the actuating step with a second coolant temperature after the actuating step as part of execution of the cooling system diagnostic algorithm; and
logging a cooling system fault if a comparison from the comparing step satisfies a condition as part of execution of the cooling system diagnostic algorithm.
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Accused Products
Abstract
An onboard cooling system diagnostic strategy utilizes at least one temperature sensor fluidly positioned between an electronically controlled engine and a thermostat. The diagnostic algorithm operates by monitoring coolant temperature during engine startup. By comparing the actual coolant temperature during engine start-up to a predicted coolant temperature that should occur if no cooling system error is present, a cooling system fault condition may be identified. If a cooling system fault is detected, the diagnostic logic may activate the engine cooling fan or intrusively open an electrically controlled thermostat while monitoring the coolant temperature response to the intrusive action. If there is a substantial change in coolant temperature responsive to the intrusive action, this phenomenon can be utilized to correctly distinguish between a thermostat failure and a vehicle configuration error corresponding to an overcooled vehicle. The present disclosure also can utilize a similar strategy to diagnose problems associated with other vehicle fluid coolers that exchange heat with ambient air moved by a circulation fan.
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Citations
20 Claims
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1. An engine cooling system diagnostic method, comprising the steps of:
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initiating execution of a cooling system diagnostic algorithm; recording a coolant temperature for at least one location at a plurality of times as part of execution of the cooling system diagnostic algorithm; actuating a cooling system electrical actuator intrusively as part of execution of the cooling system diagnostic algorithm when a cooling system controller has the cooling system electrical actuator deactuated; comparing a first coolant temperature before the actuating step with a second coolant temperature after the actuating step as part of execution of the cooling system diagnostic algorithm; and logging a cooling system fault if a comparison from the comparing step satisfies a condition as part of execution of the cooling system diagnostic algorithm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An engine system comprising:
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an electronically controlled engine that includes an electronic controller; a cooling system fluidly connected to the electronically controlled engine, and including a thermostat, and a temperature sensor positioned for sensing a coolant fluid temperature fluidly positioned between the thermostat and the electronically controlled engine; the temperature sensor being in communication with the electronic controller; and the electronic controller being configured to execute a cooling system diagnostic algorithm operable to log one of a cooling configuration fault and a thermostat fault. - View Dependent Claims (12, 13, 14, 15)
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16. A machine comprising:
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a machine body; an engine system attached to the machine body and including an electronically controlled engine that includes an electronic controller;
a cooling system fluidly connected to the electronically controlled engine, and including a thermostat, and a temperature sensor positioned for sensing a coolant fluid temperature fluidly positioned between the thermostat and the electronically controlled engine; and
the temperature sensor being in communication with the electronic controller; and
, the electronic controller being configured to execute a cooling system diagnostic algorithm operable to log one of a machine cooling configuration fault and a thermostat fault; andat least one machine heat exchanger attached to the machine body and fluidly connected to the cooling system. - View Dependent Claims (17, 18, 19, 20)
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Specification