Coolant Temperature Sender - Revision history

Geoff at 05:44, 26 October 2011

2011-10-26T05:44:54Z

Geoff at 00:14, 26 April 2010

2010-04-26T00:14:42Z

Geoff at 23:37, 25 April 2010

2010-04-25T23:37:31Z

Geoff at 00:37, 31 January 2010

2010-01-31T00:37:28Z

Geoff at 00:35, 31 January 2010

2010-01-31T00:35:51Z

Foo: Category:Components

2008-05-10T17:58:48Z

Category:Components

Geoff at 00:37, 12 March 2008

2008-03-12T00:37:05Z

Geoff at 00:33, 12 March 2008

2008-03-12T00:33:50Z

Geoff: New page: The Coolant Temperature Sender (not to be confused with the Coolant Temperature Sensor used by the ECU) is also a negative temperature coefficient (NTC) thermistor that allows the ...

2008-03-12T00:32:36Z

New page: The Coolant Temperature Sender (not to be confused with the Coolant Temperature Sensor used by the ECU) is also a negative temperature coefficient (NTC) thermistor that allows the ...

New page

The Coolant Temperature Sender (not to be confused with the [[Coolant Temperature Sensor]] used by the [[ECU]]) is also a negative temperature coefficient (NTC) thermistor that allows the temperature gauge to display engine temperature. The temperature gauge is provided with a precision 10V supply and current flows through the gauge and via the sender to ground.

Empirical data for the effect of various resistors on the temperature gauge is as follows (sender resistance | sender voltage | gauge position | temperature):

35.6 | 4.00 | 8/8 | 115°C

48.7 | 4.80 |

50.0 | 4.90 | 6/8 | 105°C

60.0 | 5.30 |

70.0 | 5.75 | 4/8 | 95°C

85.3 | 6.20 |

100. | 6.60 | 2/8 | 85°C

120. | 7.00 | 1/8 | 80°C

153. | 7.50 | 0/8 | 75°C

200. | 8.00 |

This fits well with the gauge having a resistance of 52 ohms and the thermistor having Ro=1700 ohms and Beta=5000. This results in a reasonably linear relationship between temperature and sender voltage: V ~ 14 - 0.087 × T(°C)

← Older revision		Revision as of 05:44, 26 October 2011
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−	[[Image:~~Fan_Switch~~.jpg]]	+	[[Image:Coolant_SensorSenderSwitch.jpg]]

	[[Category:Components]]		[[Category:Components]]

← Older revision		Revision as of 00:14, 26 April 2010
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	In all cases the power dissipated in the resistor is manageable and 300 ohms is less than ¼W and 56 ohms is less than ½W.		In all cases the power dissipated in the resistor is manageable and 300 ohms is less than ¼W and 56 ohms is less than ½W.
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		+
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		+	[[Image:Fan_Switch.jpg]]

	[[Category:Components]]		[[Category:Components]]

← Older revision		Revision as of 23:37, 25 April 2010
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	== Background ==		== Background ==
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		+	[[Image:Coolant_temperature_sender.gif]]

@@ Line 21: / Line 21: @@
 Column 4: Temperature (Temp)
 .6 | 4.00 | 8/8 |
@@ Line 41: / Line 42: @@
 .  | 8.00 |
 The reference voltage (Vref) was measured as 10.1V.
 Some simple analyses can be performed:
 a) The gauge resistance (Rgauge) can be determined as:
@@ Line 53: / Line 56: @@
 The average value from the above 10 data points gives Rgauge = 53.4 ohms.
 b) The resistance of the sender (thermistor) is R = Ro × exp(β × ( 1 / T - 1 / To)) where
@@ Line 65: / Line 69: @@
 Fitting to the approximate temperatures at 1/4 and 3.4 scale gives values of Ro(+25°C) = 1085 ohms and β = 4560.
 c) Temperature gauges are usually linear with current but with an offset current before they start to read. Plotting the gauge position (Pos%) against the current (I = Vref / (Rsensor + Rgauge)) gives a good fit to the curve
@@ Line 72: / Line 77: @@
 The offset current is therefore 0.775 / 15.6 or approximately 50mA.
 Combining the above gives us an equation for the gauge position vs temperature:
 Pos% = 15.6 × Vref / (Rgauge +  Rsender) - 0.775 = 15.6 × 10.1 / (53.4 + 1085 × exp(4560 × ( 1 / (Temp + 273.15) - 1 / 298.15))) - 0.775

← Older revision		Revision as of 17:58, 10 May 2008
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	This results in a reasonably linear relationship between temperature and sender voltage: V ~ 14 - 0.087 × T(°C). For example, the sender voltage at 95°C is 5.74V and 90°C is 6.17V.		This results in a reasonably linear relationship between temperature and sender voltage: V ~ 14 - 0.087 × T(°C). For example, the sender voltage at 95°C is 5.74V and 90°C is 6.17V.
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		+	[[Category:Components]]

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-The Coolant Temperature Sender (not to be confused with the [[CTS|Coolant Temperature Sensor]] used by the [[ECM]]) is also a negative temperature coefficient (NTC) thermistor that allows the temperature gauge to display engine temperature. The temperature gauge is provided with a precision 10V supply and current flows through the gauge and via the sender to ground.
+== Background ==
-.6 | 4.00 | 8/8 | 115°C
+The Coolant Temperature Sender (not to be confused with the [[CTS|Coolant Temperature Sensor]] used by the [[ECM]]) is also a negative temperature coefficient (NTC) thermistor that allows the temperature gauge to display engine temperature. The temperature gauge is provided with a precision 10±0.1V supply and current flows through the gauge and via the sender to ground.
 .7 | 4.80 |
-.0 | 4.90 | 6/8 | 105°C
+.0 | 4.90 | 6/8 | 100°C
 .0 | 5.30 |
-.0 | 5.75 | 4/8 | 95°C
+.0 | 5.75 | 4/8 |
 .3 | 6.20 |
-.  | 6.60 | 2/8 | 85°C
+.  | 6.60 | 2/8 | 80°C
-.  | 7.00 | 1/8 | 80°C
+.  | 7.00 | 1/8 |
-.  | 7.50 | 0/8 | 75°C
+.  | 7.50 | 0/8 |
 .  | 8.00 |
-This fits well with the gauge having a resistance of 52 ohms and the thermistor having Ro=1700 ohms and Beta=5000.
+The reference voltage (Vref) was measured as 10.1V.
-This results in a reasonably linear relationship between temperature and sender voltage: V ~ 14 - 0.087 × T(°C). For example, the sender voltage at 95°C is 5.74V and 90°C is 6.17V.
+In all cases the power dissipated in the resistor is manageable and 300 ohms is less than ¼W and 56 ohms is less than ½W.
 [[Category:Components]]

← Older revision		Revision as of 00:37, 12 March 2008
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	200. \| 8.00 \|		200. \| 8.00 \|

−	This fits well with the gauge having a resistance of 52 ohms and the thermistor having Ro=1700 ohms and Beta=5000. This results in a reasonably linear relationship between temperature and sender voltage: V ~ 14 - 0.087 × T(°C)	+	This fits well with the gauge having a resistance of 52 ohms and the thermistor having Ro=1700 ohms and Beta=5000.
		+
		+	This results in a reasonably linear relationship between temperature and sender voltage: V ~ 14 - 0.087 × T(°C). For example, the sender voltage at 95°C is 5.74V and 90°C is 6.17V.

← Older revision		Revision as of 00:33, 12 March 2008
Line 1:		Line 1:
−	The Coolant Temperature Sender (not to be confused with the [[Coolant Temperature Sensor]] used by the [[~~ECU~~]]) is also a negative temperature coefficient (NTC) thermistor that allows the temperature gauge to display engine temperature. The temperature gauge is provided with a precision 10V supply and current flows through the gauge and via the sender to ground.	+	The Coolant Temperature Sender (not to be confused with the [[CTS\|Coolant Temperature Sensor]] used by the [[ECM]]) is also a negative temperature coefficient (NTC) thermistor that allows the temperature gauge to display engine temperature. The temperature gauge is provided with a precision 10V supply and current flows through the gauge and via the sender to ground.

	Empirical data for the effect of various resistors on the temperature gauge is as follows (sender resistance \| sender voltage \| gauge position \| temperature):		Empirical data for the effect of various resistors on the temperature gauge is as follows (sender resistance \| sender voltage \| gauge position \| temperature):