JPS6367842B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a water temperature gauge for an automobile that holds the display on a display device within a hold temperature range, in particular, the hold temperature range can be adjusted depending on the height of the outside air temperature, and as the outside air temperature increases, the above hold temperature increases. This invention relates to a water temperature gauge for an automobile that adjusts the range to a relatively low temperature.

Generally, in a car water temperature gauge that displays the coolant temperature of the car engine, when the engine coolant temperature is within a certain normal water temperature range, the meter support is held in a constant position so that the engine is in a stable state. A method is used to show that

For this reason, it has conventionally been possible to adjust the indicated angle in low and high temperature ranges by supplying a nonlinear voltage output from a nonlinear function generator configured using a Zener diode or the like to the meter via a differential amplification circuit. A wide-angle device is known in which the rotation of the pointer is stopped only within a certain temperature range in the middle (see, for example, Japanese Utility Model Application No. 55-49286).

By the way, this type of car water temperature gauge uses a nonlinear voltage output from a nonlinear function generator to stop the pointer from rotating within a certain temperature range, but it has nothing to do with the outside temperature. It was hot. However, in the summer when the outside air temperature is high, it is desirable to have a display that responds sensitively to overheating, and conversely, in the winter when the cooling water temperature does not rise very often, it is desirable to have a display that focuses on temperature increases in low-temperature ranges.

The present invention was made to solve these problems with conventional automobile water temperature gauges, and its purpose is to detect the outside air temperature and shift the hold temperature range of the engine cooling water temperature to the lower temperature side in the summer. While the display of the high temperature range starts from a relatively low temperature, in winter the hold temperature range of the engine cooling water temperature is shifted to the high temperature side and the display of the low temperature range is performed until the temperature is relatively high.

Therefore, in the present invention, an engine cooling water temperature detection circuit that detects the engine cooling water temperature, an outside air temperature detection circuit that detects the outside air temperature, and an engine cooling water temperature signal output from the engine cooling water temperature detection circuit are input. , a normal coolant temperature range correction signal that changes according to changes in the coolant temperature signal in a predetermined normal water temperature range within the rising range of engine coolant temperature; A first temperature range correction signal that changes according to changes in the cooling water temperature signal in one temperature range, and a second temperature range that extends from the normal water temperature range to a higher temperature range. generates a second temperature range correction signal that changes according to a change in the cooling water normal temperature range correction signal when the outside air temperature detected by the outside air temperature detection circuit is in a preset normal temperature range; When the outside air temperature is in a cold range lower than the normal temperature range, the second temperature range correction signal is sent, and when the outside air temperature is in a high temperature range higher than the normal temperature range, the first temperature range correction signal is sent. A correction circuit that selects and outputs each of The present invention is characterized by comprising a water temperature data processing circuit that outputs a signal having a dead band with respect to changes in the engine cooling water temperature signal by offsetting the engine cooling water temperature signal, and a display device that displays the output of the water temperature data processing circuit.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In Figure 1, 11 is a car (not shown).
A water temperature sensor that detects the cooling water temperature of the engine, 1
2 is a display driver that converts the cooling water temperature detected by the water temperature sensor 11 into a signal for displaying a bar graph; 13 is a bar graph that displays the cooling water temperature; 14 is an outside temperature sensor that detects outside air temperature;
Reference numeral 5 denotes a correction circuit that selects and outputs a correction signal, which will be described later, corresponding to each temperature range preset for the outside air temperature; 16, an output vt of this correction circuit 15 and an output v of the temperature sensor 11; This is a water temperature data processing circuit that outputs a display signal in which the hold temperature range changes according to each outside air temperature range.

The water temperature sensor 11 and the outside temperature sensor 14 are both composed of a thermistor or the like, and the water temperature sensor 11
is connected in series with a resistor R ₁ between the power supply Vcc and ground, and the outside temperature sensor 14 is connected in series with a resistor R ₂
and is connected in series between the power supply Vcc and ground.

Connection point 17 between the water temperature sensor 11 and resistor R ₁
The signal v output from the correction circuit 15 and the water temperature data processing circuit 1 is used as a signal representing the cooling water temperature.
6, respectively.

On the other hand, a signal output from the connection point 18 between the outside air temperature sensor 14 and the resistor _R2 is applied to the correction circuit 15 as a signal representing the outside air temperature Ta.

As shown in FIG. 2, the water temperature data processing circuit 16 outputs any one of the three display characteristics l ₁ , l ₂ and l ₃ that determine the displayed value of the bar graph 13 for the cooling water temperature. A signal is selected and a signal corresponding to the selected display characteristic is output. These display characteristics l ₁ , l ₂ and l ₃ are selected according to a predetermined temperature range of the outside air temperature Ta.

The above display characteristics l ₁ , l ₂ and l ₃ are, for example, when the outside temperature Ta (°C) is 30Ta (high temperature range), 10<Ta<30
(normal temperature range) and Ta10 (cold range), respectively.

The above display characteristic l ₁ indicates that the cooling water temperature Tw is t ₁ < Tw < t ₄
(first temperature range), and in this dead band, from the lowest segment Sc of bar graph 13 to
Up to Si _-1 lights up.

In addition, the display characteristic l ₂ indicates that the cooling water temperature Tw is (t ₁ <) t ₂
It has a dead zone in the range of <Tw (<t ₄ ) <t ₅ (normal water temperature range), and in this dead zone, the lowest segments Sc to Si of the bar graph 13 are lit.

Furthermore, the display characteristic l ₃ indicates that the cooling water temperature Tw is (t ₂ <)
It has a dead zone in the range of t ₃ <Tw (<t ₅ ) <t ₆ (second temperature range), and in this dead zone, the lowest segments Sc to Si ₊₁ of the bar graph 13 are lit.

For example, as shown in FIG. 3, the correction circuit 15 includes comparators 21 and 10<
Comparator 22 and Tw which becomes “1” when Tw<30
It has a comparator 23 which becomes "1" at 10.

The correction circuit 15 also includes nonlinear circuits 24, ₂₅ , and 26 whose output voltage vt changes as shown in FIG. Transfer gates 27 and 2 are provided between the nonlinear circuit 24 and the adder 31, between the nonlinear circuit 25 and the adder 32, and between the nonlinear circuit 26 and the adder 33, respectively.
8 and 29 are connected, respectively.

After the output of the adder 33 has its sign changed, it is added to the signal v in a water temperature data processing circuit 16 consisting of an adder, and is input to the display driver 12.

With this configuration, as shown in Figure 2, in the summer when the outside air temperature Ta is high (30Ta),
The output of the comparator 21 of the correction circuit 15 becomes "1". At this time, the transfer gate 27 is opened, and the output vt of the nonlinear circuit 24 and the output v of the water temperature sensor 11 (which changes as shown in FIG.
It is added at step 6.

As a result, from the water temperature data processing circuit 16,
The characteristics shown in Fig. 2 for the output v of the water temperature sensor 11
A signal that changes according to _l1 is output. For this reason, when the cooling water temperature Tw reaches a relatively low temperature _t1 , the bar graph 13 enters the dead zone, and from then on, within a constant temperature range until _t4 , when the output change of the nonlinear circuit 24 stops, the segments Sc, ..., Si _{- 1} , Si, Si ₊₁ ,…, Sh is
Segments Sc to Si _-1 are held lit. When the water temperature rises further and exceeds temperature t ₄ , the display in the high temperature range starts, but t ₄ is lower than t ₅ and t ₆ , and the display start point in the high temperature range is lower than when the outside temperature is lower. decreases, allowing you to quickly respond to overheating.

When the outside air temperature Ta is in the range of 10<Ta<30 (for example, in spring or autumn), the output of the comparator 22 of the correction circuit 15 becomes "1". At this time, the transfer gate 28 opens and the output of the nonlinear circuit 25
vt and the above-mentioned output v of the water temperature sensor 11 are added in the water temperature data processing circuit 16.

As a result, from the water temperature data processing circuit 16,
The characteristics shown in Fig. 2 for the output v of the water temperature sensor 11
A signal that changes according to _l2 is output. For this reason,
When the cooling water temperature Tw reaches t ₂ , the bar graph 13 enters the dead zone, and thereafter, in a constant temperature range until t ₅ when the output change of the nonlinear circuit 25 stops, the segments Sc, ..., Si _-1 of the bar graph 13 ,Si,Si ₊₁ ,…,
For Sh, segments Sc to Si are lit, and the standard cooling water temperature is displayed when the cooling water temperature Tw is in the range of t ₂ < Tw < t ₅ .

On the other hand, in the winter season (Ta10) when the outside air temperature Ta is low, the output of the comparator 23 of the correction circuit 15 becomes "1". At this time, the transfer gate 29 is opened, and the output vt of the nonlinear circuit 26 and the output v of the water temperature sensor 11 are added in the water temperature data processing circuit 16.

As a result, from the water temperature data processing circuit 16,
The characteristics shown in Fig. 2 for the output v of the water temperature sensor 11
l Outputs a signal that changes according to ₃ . For this reason,
The cooling water temperature Tw exceeds t ₁ to t ₂ , and the cooling water temperature Tw exceeds t ₃
The bar graph 13 enters the dead zone only after reaching , and from then on, the output change of the nonlinear circuit 26 stops.
At a constant temperature range up to t ₆ , the segment Sc,
..., Si _-1 , Si, Si ₊₁ , ..., Sh, the segments Sc to Si ₊₁ are lit, and the temperature rise in the low temperature range can be displayed over a wide range.

Further, in the above three cases, the number of segments lit in the hold temperature range is small when the outside temperature is high, and is large when the outside temperature is low. This has the advantage of counteracting the feeling of overheating or overcooling that the driver feels in summer and winter, even though the vehicle is in a normal state.

As is clear from the detailed explanation above, the present invention corrects the temperature of the predetermined intermediate range of engine cooling water to the lower temperature side when the outside air temperature is high, and to the higher temperature side when the outside air temperature is low. However, when the outside temperature is high, the display start point of the high temperature range is lower than the middle range, so the temperature rise point of the cooling water temperature is earlier in the summer, and the temperature rise point of the cooling water temperature is later in the winter. will be displayed respectively,
It can respond quickly to overheating of an automobile engine in the summer, and display the process of increase in engine cooling water temperature in the winter over a wide temperature range.

In the present invention, it is also possible to use a needle-type meter, a digital display meter, or the like instead of a bar graph as a display means for displaying the engine cooling water temperature. Further, the outside temperature detection signal is not limited to three levels as described above, but can be arbitrarily selected. Furthermore, it goes without saying that the signal may be extracted as a linear signal instead of a stepwise signal.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a water temperature gauge for an automobile according to the present invention, Fig. 2 is a display characteristic diagram stored in the correction circuit of Fig. 1, and Fig. 3 is an explanatory diagram showing details of Fig. 1. . 11...Water temperature sensor, 12...Display driver, 13...Bar graph, 14...Outside temperature sensor, 1
5... Correction circuit, 16... Water temperature data processing circuit.

Claims (1)

[Claims] 1 The engine coolant temperature detection circuit that detects the engine coolant temperature, the outside air temperature detection circuit that detects the outside air temperature, and the engine coolant temperature signal output from the engine coolant temperature detection circuit are input, and the engine coolant temperature increases. A cooling water normal temperature range correction signal that changes according to changes in the cooling water temperature signal within a predetermined normal water temperature range, and cooling in a first temperature range from a temperature lower than the normal water temperature range to the normal water temperature range. A first temperature range correction signal that changes according to changes in the water temperature signal, and a second temperature range that changes according to changes in the cooling water temperature signal in a second temperature range from the normal water temperature range to a higher temperature range. When the outside temperature detected by the outside air temperature detection circuit is in a preset normal temperature range, the cooling water normal temperature range correction signal is generated, and when the outside air temperature is within a preset normal temperature range, When the temperature is in a cold region lower than the temperature range, the second temperature range correction signal is sent;
a correction circuit that selects and outputs the first temperature range correction signal when the outside air temperature is in a high temperature range higher than the normal temperature range; and an engine that outputs the output of the correction circuit and the engine cooling water temperature detection circuit. a water temperature data processing circuit that outputs a signal having a dead band with respect to changes in the engine cooling water temperature signal by adding the cooling water temperature signal output of A water temperature gauge for an automobile, comprising a display device that displays the output of a data processing circuit.