Apparatus for monitoring an oil thermostat
First Claim
1. An apparatus for monitoring an oil thermostat arranged in an oil circuit of an internal combustion engine, wherein the oil thermostat is configured to supply an oil flow to a first flow branch in which an oil cooler is arranged or to a bypass flow branch depending on an admission temperature (T2) of the oil flow supplied to the oil thermostat which is measured at an oil sump, wherein a first outlet of the oil thermostat, which outlet is assigned to the first flow branch, is closed when the admission temperature (T2) lies below a first temperature threshold value (T1), wherein the apparatus comprises:
- (a) a sensor device which is configured to measure the admission temperature (T2) of the oil as a first parameter by means of which a current desired operation of the oil thermostat can be derived, and to determine at least one second parameter by means of which a current actual operation of the oil thermostat can be derived; and
(b) an evaluation device which is configured, depending on the first parameter and the second parameter, to identify an occurrence of a malfunction of the oil thermostat, wherein(a) the sensor device is configured to measure a second oil temperature (T3) downstream of the oil cooler and upstream of the internal combustion engine and to determine a temperature difference (Δ
T) from the admission temperature (T2) minus the second oil temperature (T3) as the second parameter; and
(b) the evaluation device identifies the occurrence of a malfunction of the oil thermostat,(b1) when the admission temperature (T2) lies below the first temperature threshold value (T1), at least one predetermined reaction period (Z1) has elapsed since the admission temperature (T2) has been below the first temperature threshold value (T1), and the temperature difference (Δ
T) is greater than a first threshold value (Δ
T1), or(b2) when the admission temperature (T2) is above the first temperature threshold value (T1) at least one predetermined reaction period (Z1) has elapsed since the admission temperature (T2) has been above the first temperature threshold value (T1), and the temperature difference (Δ
T) is smaller than a second threshold value (Δ
T2);
or(c) when, after the first temperature threshold value (T1) is exceeded by the admission temperature (T2), an increase of the temperature difference (Δ
T) proceeds more slowly than a predetermined desired increase of the temperature difference (Δ
T).
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Accused Products
Abstract
The invention relates to an apparatus for monitoring an oil thermostat arranged in an oil circuit of an internal combustion engine. The apparatus comprises a sensor unit (4, 14b; 15) which is designed to determine at least one first parameter, by means of which a current setpoint operation of the oil thermostat (10) can be derived, and to determine at least one second parameter, by means of which a current actual operation of the oil thermostat (10) can be derived. The apparatus further comprises an evaluation device (40), which is designed to detect an onset of an error function of the oil thermostat (10) as a function of the first parameter and the second parameter.
12 Citations
15 Claims
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1. An apparatus for monitoring an oil thermostat arranged in an oil circuit of an internal combustion engine, wherein the oil thermostat is configured to supply an oil flow to a first flow branch in which an oil cooler is arranged or to a bypass flow branch depending on an admission temperature (T2) of the oil flow supplied to the oil thermostat which is measured at an oil sump, wherein a first outlet of the oil thermostat, which outlet is assigned to the first flow branch, is closed when the admission temperature (T2) lies below a first temperature threshold value (T1), wherein the apparatus comprises:
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(a) a sensor device which is configured to measure the admission temperature (T2) of the oil as a first parameter by means of which a current desired operation of the oil thermostat can be derived, and to determine at least one second parameter by means of which a current actual operation of the oil thermostat can be derived; and (b) an evaluation device which is configured, depending on the first parameter and the second parameter, to identify an occurrence of a malfunction of the oil thermostat, wherein (a) the sensor device is configured to measure a second oil temperature (T3) downstream of the oil cooler and upstream of the internal combustion engine and to determine a temperature difference (Δ
T) from the admission temperature (T2) minus the second oil temperature (T3) as the second parameter; and(b) the evaluation device identifies the occurrence of a malfunction of the oil thermostat, (b1) when the admission temperature (T2) lies below the first temperature threshold value (T1), at least one predetermined reaction period (Z1) has elapsed since the admission temperature (T2) has been below the first temperature threshold value (T1), and the temperature difference (Δ
T) is greater than a first threshold value (Δ
T1), or(b2) when the admission temperature (T2) is above the first temperature threshold value (T1) at least one predetermined reaction period (Z1) has elapsed since the admission temperature (T2) has been above the first temperature threshold value (T1), and the temperature difference (Δ
T) is smaller than a second threshold value (Δ
T2);
or(c) when, after the first temperature threshold value (T1) is exceeded by the admission temperature (T2), an increase of the temperature difference (Δ
T) proceeds more slowly than a predetermined desired increase of the temperature difference (Δ
T). - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for monitoring an oil thermostat arranged in an oil circuit of an internal combustion engine, wherein the oil thermostat is configured to supply an oil flow to a first flow branch in which an oil cooler is arranged or to a bypass flow branch depending on an admission temperature (T2) of the oil flow supplied to the oil thermostat which is measured at an oil sump, wherein a first outlet of the oil thermostat, which outlet is assigned to the first flow branch, is closed when the admission temperature (T2) lies below a first temperature threshold value (T1), wherein the apparatus comprises:
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(a) a sensor device which is configured to measure the admission temperature (T2) of the oil as a first parameter by means of which a current desired operation of the oil thermostat can be derived, and to determine at least one second parameter by means of which a current actual operation of the oil thermostat can be derived; and (b) an evaluation device which is configured, depending on the first parameter and the second parameter, to identify an occurrence of a malfunction of the oil thermostat, wherein (a) the sensor device is configured to measure, as the second parameter, an oil pressure progression (P) at a pressure measurement point which is arranged downstream of the first outlet of the oil thermostat and upstream with respect to the internal combustion engine; and (b) the evaluation device identifies a malfunction of the oil thermostat when the measured progression of the oil pressure (P) does not indicate any pressure swing (Δ
P) within a range of the admission temperature (T2) that lies between the first oil temperature threshold value (T1) and a second temperature threshold value (T1*), wherein the second temperature threshold value (T1*) lies above the first temperature threshold value (T1) and specifies a temperature threshold above which a second outlet of the oil thermostat, which outlet is assigned to the bypass flow branch, is completely closed. - View Dependent Claims (7)
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8. An apparatus for monitoring an oil thermostat arranged in an oil circuit of an internal combustion engine, wherein the oil thermostat is configured to supply an oil flow to a first flow branch in which an oil cooler is arranged or to a bypass flow branch depending on an admission temperature (T2) of the oil flow supplied to the oil thermostat, wherein a first outlet of the oil thermostat, which outlet is assigned to the first flow branch, is closed when the admission temperature (T2) lies below a first temperature threshold value (T1),(wherein the apparatus comprises:
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(a) a sensor device which is configured to measure the admission temperature (T2) of the oil as a first parameter by means of which a current desired operation of the oil thermostat can be derived, and to determine at least one second parameter by means of which a current actual operation of the oil thermostat can be derived; and (b) an evaluation device which is configured, depending on the first parameter and the second parameter, to identify an occurrence of a malfunction of the oil thermostat, wherein (a) a gradient of the oil sump is determined as the second parameter; and (b) the evaluation device establishes, depending on the determined value of the first parameter, a predetermined and stored desired characteristic curve of the gradient of the admission temperature (T2) and identifies a malfunction of the oil thermostat when the measured gradient of the admission temperature does not correspond to the desired characteristic curve.
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9. An apparatus for monitoring an oil thermostat arranged in an oil circuit of an internal combustion engine, wherein the oil thermostat is configured to supply an oil flow to a first flow branch in which an oil cooler is arranged or to a bypass flow branch depending on an admission temperature (T2) of the oil flow supplied to the oil thermostat, wherein a first outlet of the oil thermostat, which outlet is assigned to the first flow branch, is closed when the admission temperature (T2) lies below a first temperature threshold value (T1), wherein the apparatus comprises:
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(a) a sensor device which is configured to measure the admission temperature (T2) of the oil as a first parameter by means of which a current desired operation of the oil thermostat can be derived, and to determine at least one second parameter by means of which a current actual operation of the oil thermostat can be derived; and (b) an evaluation device which is configured, depending on the first parameter and the second parameter, to identify an occurrence of a malfunction of the oil thermostat, wherein (a) as the second parameter, an oil temperature is measured at a measurement point which is arranged in the first flow branch upstream with respect to the oil cooler; and (b) the evaluation device identifies a malfunction of the oil thermostat when the measured oil temperature in accordance with the second parameter remains substantially unchanged since, in accordance with the determined first parameter, the first outlet would have had to be opened or closed.
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10. An apparatus for monitoring an oil thermostat arranged in an oil circuit of an internal combustion engine, wherein the oil thermostat is configured to supply an oil flow to a first flow branch in which an oil cooler is arranged or to a bypass flow branch depending on an admission temperature (T2) of the oil flow supplied to the oil thermostat, wherein a first outlet of the oil thermostat, which outlet is assigned to the first flow branch, is closed when the admission temperature (T2) lies below a first temperature threshold value (T1), wherein the apparatus comprises:
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(a) a sensor device which is configured to measure the admission temperature (T2) of the oil as a first parameter by means of which a current desired operation of the oil thermostat can be derived, and to determine at least one second parameter by means of which a current actual operation of the oil thermostat can be derived; and (b) an evaluation device which is configured, depending on the first parameter and the second parameter, to identify an occurrence of a malfunction of the oil thermostat, wherein (a) the sensor device is configured to detect a position or a movement of a final control element of the oil thermostat as the second parameter; and (b) the evaluation device is configured to identify the malfunction of the oil thermostat with reference to the detected position or movement of the final control element. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification