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US 7,409,929 B2Granted
Cooling apparatus for internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsHideki Miyahara, Tokiji Ito
Life of this patent
Estimating the term…
Abstract
A cooling apparatus includes a thermostat that adjusts a feed rate of coolant to a radiator, estimating means that estimates a coolant temperature simulated value at least based on the detection value of an intake-air temperature sensor, and diagnosis means that diagnoses an operating state of the thermostat by comparing the detection value of a coolant temperature sensor, and the coolant temperature simulated value when a diagnosis condition is established. When a ratio of an integrated value of the simulated water temperature variation in an idle state to the integrated value of the simulated water temperature variation in a normal driving state is equal to or greater than an upper limit ratio XP, the diagnosis of the operating state of the thermostat is prohibited.
Claims19
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- and
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established,
- wherein a state in which a difference between the detection value of said intake-air temperature sensor and an external air temperature is equal to or greater than an upper limit value is set to a specific state, and wherein the diagnosis of said operating state is prohibited when a first time period of said specific state is equal to or longer than an upper limit time period, the upper limit time period being a period of time before the establishment of said diagnosis condition.
3 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established;
- and
- a correction device,
- wherein a state in which a driving speed of a vehicle is less than a reference speed is set to a specific driving state, and wherein the correction device corrects said reference temperature when a ratio of a first time period of said specific driving state to a second time period measured from a starting of the internal combustion engine until an establishment of said diagnosis condition is equal to or greater than a predetermined determination value.
4 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established;
- and
- a correction device that corrects said reference temperature when an integrated value of an intake amount from a starting of the internal combustion engine until an establishment of said diagnosis condition is less than a predetermined determination value.
3 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on an detection value of an intake-air temperature sensor;
- diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established;
- and
- a correction device,
- wherein a variation of said reference temperature during a first time period measured from a starting of the internal combustion engine until an establishment of said diagnosis condition is set to a first variation, and a variation of said reference temperature when the driving speed of a vehicle is less than a reference speed during the first time period is set to a second variation, and wherein the correction device corrects said reference temperature when a ratio of said second variation to said first variation is equal to or greater than a predetermined determination value.
4 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on an detection value of an intake-air temperature sensor;
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established;
- and
- a correction device,
- wherein a variation of said reference temperature when a driving speed of a vehicle is equal to or greater than a reference speed during a first time period measured from a starting of the internal combustion engine until an establishment of said diagnosis condition is set to a first variation, and a variation of said reference temperature when the driving speed of the vehicle is less than said reference speed during the first time period is set to a second variation, and wherein the correction device corrects said reference temperature when a ratio of said second variation to said first variation is equal to or greater than a predetermined determination value.
4 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on an detection value of an intake-air temperature sensor;
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established;
- and
- a correction device that calculates said reference temperature based on a value obtained by correcting the detection value of said intake-air temperature sensor to reduce the detection value of said intake-air temperature sensor.
3 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- and
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established,
- wherein a state in which a depression amount of an accelerator pedal is less than a predetermined value and a driving speed of a vehicle is less than a reference speed is set to an idle state, and wherein the diagnosis of said operating state is prohibited when a ratio of a first time period of said idle state to a second time period measured from a starting of the internal combustion engine until an establishment of said diagnosis condition is equal to or greater than a predetermined determination value.
3 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- and
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established,
- wherein the diagnosis of said operating state is prohibited when an integrated value of an intake amount drawn into the internal combustion engine from a starting of the internal combustion engine until an establishment of said diagnosis condition is less than a predetermined determination value.
3 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- and
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established,
- wherein a variation of said reference temperature during a first time period measured from a starting of the internal combustion engine until an establishment of said diagnosis condition is set to a first variation, wherein a variation of said reference temperature when a driving speed of a vehicle is less than a reference speed during the first time period is set to a second variation, and wherein the diagnosis of said operating state is prohibited when a ratio of said second variation to said first variation is equal to or greater than a predetermined determination value.
3 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- and
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established,
- wherein a variation of said reference temperature when a driving speed of a vehicle is equal to or greater than a reference speed during a first time period measured from a starting of the internal combustion engine until an establishment of said diagnosis condition is set to a first variation, wherein a variation of said reference temperature when the driving speed of the vehicle is less than said reference speed during the first time period is set to a second variation, and wherein the diagnosis of said operating state is prohibited when a ratio of said second variation to said first variation is equal to or greater than a predetermined determination value.
3 more elements
A cooling apparatus for an internal combustion engine, comprising:
- a thermostat that adjusts a feed rate of a coolant to a radiator;
- a detecting device that detects a temperature of said coolant;
- an estimating device that estimates a reference temperature equivalent to the temperature of said coolant at least based on a detection value of an intake-air temperature sensor;
- a diagnosis device that sets the temperature of said coolant detected by said detecting device to a detection temperature, and diagnoses an operating state of said thermostat by comparing said detection temperature and said reference temperature when a predetermined diagnosis condition is established;
- and
- a correction device,
- wherein a state in which the difference between the detection value of said intake-air temperature sensor and an external air temperature is equal to or greater than an upper limit value is set to a specific state, and wherein the correction device corrects said reference temperature when a first time period of said specific state is equal to or longer than an upper limit time period, the upper limit time period being a period of time before the establishment of said diagnosis condition.
4 more elements
Dependencies are inferred from the claim text.