Browse Prior Art Database

Automatic Automotive Vehicle Temperature Verification

IP.com Disclosure Number: IPCOM000038826D
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 3 page(s) / 37K

Publishing Venue

IBM

Related People

Ballou, R: AUTHOR [+4]

Abstract

This article describes a technique to automatically verify the accuracy of the coolant temperature sensor on an automotive vehicle. In order to meet and maintain federally regulated levels of fuel economy and exhaust emissions, manufacturers of automotive vehicles have incorporated a large number of electronic components to provide greater control over engine parameters which affect fuel economy and (Image Omitted) emissions. Fig. 1 depicts a typical electronic control system for a normally asperated internal combustion engine. The electronic control module (ECM) contains a programmable microprocessor, significant analog circuitry to read sensors and solid-state drivers to control various switches, relays and actuators.

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Automatic Automotive Vehicle Temperature Verification

This article describes a technique to automatically verify the accuracy of the coolant temperature sensor on an automotive vehicle. In order to meet and maintain federally regulated levels of fuel economy and exhaust emissions, manufacturers of automotive vehicles have incorporated a large number of electronic components to provide greater control over engine parameters which affect fuel economy and

(Image Omitted)

emissions. Fig. 1 depicts a typical electronic control system for a normally asperated internal combustion engine. The electronic control module (ECM) contains a programmable microprocessor, significant analog circuitry to read sensors and solid-state drivers to control various switches, relays and actuators. The ECM, based upon input received from a multiplicity of sensors, provides control for fuel/air mixture, spark timing, idle speed control, exhaust gas recirculation, canister purge, air conditioner (A/C) clutch, cooling fan clutch, etc. One of the key input parameters involved in the control algorithms used by the ECM is the temperature of the engine coolant. This data is provided by a coolant temperature sensor (CTS) mounted in the engine coolant system. Some of the actions taken by the ECM, based upon the coolant temperature readings, are transitioning from "open-loop" control. Until the engine reaches a specified temperature, the ECM uses default parameters to provide engine control because some of the other sensors (such as the oxygen sensor) do not operate properly until the specified temperature is reached. During the open-loop period the engine is not operating in a fuel efficient manner and the exhaust pollutants are excessive. A faulty low temperature reading will cause the ECM to stay in open-loop control mode with the attendant excess pollution and fuel consumption. Since the temperature of the engine affects the efficiency of fuel combustion, the ECM controls the fuel/air mixture based upon the coolant temperature. If the temperature reading from the CTS is false on the high side, the ECM will provide a lean fuel/air mixture, causing a loss of power. If the reading is faulty on the low side, the mixture is made rich, causing poor fuel economy and excessive exhaust pollut...