JPH0617718A - Throttle body heating device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent icing and reduce a temperature difference between a throttle body and a throttle valve. CONSTITUTION:A temperature sensor 33 for detecting a body temperature and an engine cooling water passage 30 for heating a body 14 are provided in a throttle body 14 having a throttle valve 20. Also a passage opening/closing valve 34 to shut out the cooling water passage 30 is provided therein. When an engine is started, the temperature T1 of the throttle body 14 is detected, and the passage opening/closing valve 34 is controlled in its opening and closing so as to set the temperature T1 to a value between a prescribed temperature Talpha and Talpha-Tbeta. It is thus possible to prevent icing, and also reduce a temperature difference between the throttle body 14 and the throttle valve 20, by carrying out above control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle body heating device for heating a throttle body for adjusting the intake air amount of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in a throttle body heating device disclosed in Japanese Utility Model Laid-Open No. 57-126560, a pipe member through which engine cooling water flows is attached to a throttle body. The throttle body is heated by the temperature of the cooling water flowing through the pipe member to prevent icing.

[0003]

However, at an extremely low temperature, the temperature of the throttle body rises due to the cooling water temperature, but the temperature of the throttle valve does not rise much because the intake air temperature is low. For example, as shown in FIG. 5A, when the intake air temperature is −20 ° C. and the cooling water temperature is 80 ° C., the body temperature is close to 80 ° C., but the valve is about 30 to 40 ° C. Only rises. At this time, since the expansion of the body is larger than the expansion of the valve, the gap between the body and the valve becomes large. Therefore, when the valve is fully closed, the amount of air leaking from this gap may increase and the idle speed may increase.

Further, even in an internal combustion engine provided with an idle speed control for feedback controlling the rotational speed during idling to a target value, the air amount of a bypass control valve that bypasses the throttle valve is reduced while the leak air amount is small. However, if the amount of leaked air eventually increases, the target rotation speed cannot be reduced even if the bypass control valve is fully closed.

In view of the above problems, it is an object of the present invention to reduce the temperature difference between the throttle valve and the throttle body while preventing icing.

[0006]

In order to achieve the above object, the present invention provides a throttle body having a throttle valve for adjusting the intake air amount of an internal combustion engine, a detecting means for detecting the temperature of the throttle body, and A heating unit for heating the throttle body, and a temperature for adjusting the temperature of the throttle body by heating the throttle body by the heating unit or stopping the heating according to the throttle body temperature detected by the detecting unit. The technical means of being a throttle body heating device for an internal combustion engine, which is provided with an adjusting means.

[0007]

In the above throttle body heating device, the temperature of the throttle body is detected by the detection means provided in the throttle body provided with the throttle valve. Further, heating means for heating the throttle body is provided. The temperature adjusting means is provided with temperature adjusting means for adjusting the temperature of the throttle body by causing the heating means to heat the throttle body and stop heating in accordance with the throttle body temperature detected by the detecting means. The temperature of the throttle body adjusted by the temperature adjusting means prevents icing, reduces the temperature difference between the throttle body and the throttle valve, and reduces the amount of air leaking from the gap between the throttle body and the throttle valve. .

[0008]

EXAMPLE A first example to which the present invention is applied will be described below. FIG. 1 is a block diagram of an internal combustion engine intake system provided with a throttle body heating device of the present embodiment, and FIG. 2 is II of FIG.
FIG. 3 is a cross-sectional view, and FIG. 3 is a view on arrow II in FIG. 2.

In FIG. 1, the intake system of the internal combustion engine 1 includes:
An air cleaner 10 for removing impurities such as dust and dust in intake air, an air flow meter 12 for detecting the intake air amount, and a throttle body 14 having a throttle valve 20 for adjusting the intake air amount are provided. The air taken into the engine 1 passes through this intake system and is taken into the cylinder of the engine 1. The throttle valve 20 is fixed to a shaft 22 with bolts 24 or the like as shown in FIG. The shaft 22 is connected to an accelerator pedal 29 by a wire 28 to obtain a throttle opening degree according to the depression of the accelerator pedal 29,
The amount of air into the internal combustion engine 1 is adjusted. In addition, the intake air temperature sensor 1 for detecting the intake air temperature is provided in the air flow meter 12.
3, a cooling water temperature sensor 15 for detecting the engine cooling water temperature is provided on the cylinder outer wall of the engine 1.

An electronically controlled engine control unit (ECU) 2 controls the fuel injection amount and the fuel injection amount according to the intake air amount signal from the air flow meter 12 and the engine rotation speed obtained from the signal obtained from the rotation angle sensor 11. Calculate the ignition timing. Further, the injection amount and the ignition timing are corrected by the cooling water temperature detected by the cooling water temperature sensor 15 and the like, and a drive signal corresponding to this is sent to the fuel injection valve 16 and the igniter 17.

A cooling water passage 30, which is a heating means shown in FIGS. 1, 2, and 3, is attached to the outer wall of the throttle body 14. A cooling water introduction pipe 35 is attached to the inlet 31 of the passage 30, and a cooling water outlet pipe (not shown) is attached to the outlet 32. Then, the cooling water heated by the internal combustion engine 1 flows from the inlet 31 to the outlet 32 and heats the throttle body 14. An electromagnetic passage opening / closing valve 34 is provided in the cooling water introduction pipe 35 upstream of the inlet 31. The valve 34 is normally opened so as to pass the cooling water to the cooling water passage 30 and closes the passage when receiving a drive signal from the ECU 2. Therefore, this valve 34 and the ECU
2 constitutes a temperature adjusting means for adjusting the temperature of the throttle body 14.

Further, the throttle body 14 is provided with a temperature sensor 33 showing a detecting means for detecting the body temperature. Next, the operation of the embodiment having the above configuration will be described with reference to the flowchart of FIG.

In step 100, the throttle body 14
The temperature T1 is detected by the temperature sensor 33. Then, in step 101, it is determined whether or not the flag F = 1. Here, if the flag F = 1, the passage opening / closing valve 34
Is open, and if the flag F = 0, the passage opening / closing valve 34 is set to be closed.

When the flag F = 1, that is, when the passage opening / closing valve 34 is open, the routine proceeds to step 102, where the cooling water temperature T1 detected at step 100 is the set temperature Tα.
Determine if it is higher or not. This set temperature Tα is, eg, 20 ° C. If the cooling water temperature T1 is lower than the temperature Tα, the routine proceeds to step 103, the passage opening / closing valve 34 is opened, and at step 104, the flag F = 1 is set and the processing ends. In this case, at the time of step 100, the passage opening / closing valve 34
Is open, the valve 34 is left open and the processing is terminated. On the other hand, if T1 is equal to or greater than Tα, the routine proceeds to step 105, where the passage opening / closing valve 34 is closed. And step 104
Then, the flag F = 0 is set and the processing is ended.

If the flag F = 1 is not satisfied in step 101, that is, the flag F = 0 and the passage opening / closing valve 34 is closed, the routine proceeds to step 107. Then, it is determined whether the cooling water temperature T1 is higher than the set temperature Tα-Tβ. The set temperature Tα-Tβ is set to, for example, 15 ° C.
If the cooling water temperature T1 is lower than the temperature Tα-Tβ, the routine proceeds to step 103, where the passage opening / closing valve 34 is opened to raise the throttle body temperature. Then, in step 104, the flag F = 1 is set, and the process ends. On the other hand, T1 is Tα-Tβ
If the above is the case, a command to close the passage opening / closing valve 34 is received in steps 105 and 106, so the process ends with the valve 34 closed.

By the above processing, the temperature T1 of the throttle body 14 is maintained substantially between the set temperatures Tα and Tα-Tβ as shown in FIG. 5 (b). Thus, the temperature of the throttle body 14 shown in FIG. 5 (b) is made lower than the temperature of the throttle body 14 shown in FIG. 5 (a), and the intake air temperature (in the case of FIG. 5, the intake air temperature is −20 ° C.). .), The amount of heat given from the throttle body 14 to the throttle valve 20 decreases. Therefore, the temperature of the throttle valve 20 drops. Then, the temperature difference between the temperature of the throttle valve 20 and the intake air temperature becomes small. When this temperature difference becomes small, the throttle valve 20
The amount of heat drawn from the intake to the intake is reduced. Therefore, as indicated by ΔT in FIGS. 5A and 5B, the temperature difference between the throttle body 14 and the throttle valve 20 becomes small.

As a result, the temperatures of the throttle body 14 and the throttle valve 20 are set to the set temperatures Tα, Tα-Tβ.
Since it is near, it is possible to prevent icing of the throttle device at extremely low temperatures. At the same time, the temperature difference between the throttle body 14 and the throttle valve 20 can be reduced. Therefore, the throttle body 1
Since the expansion difference between the throttle valve 4 and the throttle valve 20 can be reduced, the amount of air leaking from the gap between the throttle body 14 and the throttle valve 20 can be reduced. Therefore, it is possible to prevent the idle speed from increasing due to leaked air.

In order to set the predetermined temperatures Tα and Tα-Tβ, it is necessary to reduce the difference between the throttle body temperature and the throttle valve temperature as described above.
How much the throttle valve temperature rises depends on various conditions such as the intake air temperature and the intake air amount as well as the difference depending on the model. That is, the lower the intake air temperature,
Alternatively, as the intake air amount increases, the heat amount taken from the throttle valve 20 increases and the temperature decreases. Therefore, the intake air amount and the intake air temperature sensor 1 obtained from the air flow meter 12
Alternatively, Tα and Tβ may be changed according to the intake air temperature obtained from No. 3.

Next, another embodiment will be described. In the above embodiment, the temperature of the throttle body 14 is directly detected by the temperature sensor 33, but it may be obtained by estimation.
The procedure of the means for detecting the throttle body temperature based on the estimation will be described below.

The factors that determine the temperature of the throttle body 14 are as follows. (A) intake air temperature, (b) intake air amount, (c) cooling water temperature,
(D) amount of cooling water, (e) time after starting the internal combustion engine 1, and the like.

As the intake air amount increases, the temperature of the throttle body 14 approaches the intake air temperature, and as the cooling water amount increases, the temperature of the throttle body 14 approaches the cooling water temperature. Further, when the internal combustion engine is started, the temperature of the throttle body 14 is substantially equal to the temperature of the cooling water, but eventually converges to a temperature determined by the factors (a) to (d).

Therefore, the temperature TB of the throttle body 14 is obtained as described below. Air flow meter 12
Intake air amount QA, intake air temperature T
A, the cooling water temperature TW is obtained by the cooling water temperature sensor 15. The amount of cooling water is determined by the discharge amount from a water pump (not shown), but since the discharge amount of the water pump is proportional to the engine rotation speed, the cooling water amount QW is calculated according to the engine rotation speed obtained from the rotation angle sensor 11. When the passage opening / closing valve 34 is closed, it is estimated that the temperature of the cooling water will gradually decrease from the temperature before the closing.

Using the above values, the throttle body 14
The temperature TB of is calculated by the following mathematical formula 1.

[0024]

## EQU1 ## TB = (K1 × QA × TA + K2 × QW × TW) / K3 Note that K1, K2, and K3 are constants determined by the engine.

Further, after the engine is started, the temperature TB of the throttle body 14 obtained by the equation 1 is corrected within a predetermined time as shown by the following equation 2.

[0026]

TB ′ = (t1 × TWS + (t1−t2) × TB) / t2 where t2 is the time for correction after starting the internal combustion engine, t1 is the elapsed time after starting the internal combustion engine, and TWS is when starting the internal combustion engine. Shows the cooling water temperature.

In this way, the estimated temperature of the throttle body 14 is used instead of the temperature T1 of the throttle body 14 detected by the temperature sensor 33 of the first embodiment.

As a result, not only the effects of the first embodiment described above but also the temperature sensor 33 need not be provided, so that space saving and cost reduction can be achieved. In addition, FIG.
Instead of the cooling water passage 30, a heater 50 whose energization is controlled by the ECU 2 may be provided on the outer circumference of the throttle body 14 as shown in FIG. A flow chart when the heater 50 is provided is shown in FIG. This flow chart is obtained by modifying or adding a part of the flow chart shown in FIG. 4 of the first embodiment. Step 103 in FIG.
0 is changed to a command to turn on, and step 105 is changed to a command to turn off the heater 50. Then, step 90 is added so that the intake air temperature TA detected by the intake air temperature sensor 13 is a predetermined temperature T0 (for example, T0 =
(5 ° C) or lower, it is determined that icing of the throttle valve 20 may occur, and the step 10
Try to go to 0. When the intake air temperature TA is higher than the predetermined temperature T0, the process is ended. by this,
Since the energization control to the heater 50 is performed only when the intake air temperature at which icing is likely to occur, the heater 50 is not energized frequently, and the life of the heater 50 can be improved.

As a result, the cooling water passage, passage opening / closing valve and the like as in the first embodiment can be eliminated, so that the storability is improved. Further, the heater 50 heats the throttle body 14 faster than the cooling water when the engine is started.

The energization of the heater 50 is controlled by the ECU 2.
Instead, a heat-sensitive switch (bimetal or the like) attached to the throttle body 14 and acting as a detecting means may be used. In addition, the temperature of the throttle body 14 is set to the above second value.
The estimation may be performed as shown in the embodiment. In this case, the heater heating amount is used instead of QW × TW in Expression 1.

Further, a PTC heater in which the heater 50 itself is saturated at a predetermined temperature may be used. This PTC heater acts as a heating means, a detecting means, and a temperature adjusting means. In this case, the saturation temperature is set to be about the set temperature Tα in the first embodiment.

Further, as shown in FIG. 8, a wax type temperature sensitive body 42 that contacts the throttle body 14 may be provided, and a valve 43 that is driven by expansion and contraction of the temperature sensitive body 42 may be provided. The temperature sensitive body 42 acts as a detecting means and a temperature adjusting means. FIG. 9 is a sectional view of the cooling water passage 30.
When the temperature of the throttle body 14 becomes Tα, the temperature sensitive element 42 expands and closes the valve, and when it becomes Tα−Tβ, the temperature sensitive element 42 contracts and the valve opens. As a result, the temperature of the throttle body 14 can be maintained substantially between Tα and Tα−Tβ, and the temperature difference between the throttle body 14 and the throttle valve 20 can be reduced.

Further, as shown in FIG. 10, the cooling water passage 30 is provided.
A wax type temperature sensitive body 44 may be provided therein, and a valve 45 that is driven by expansion and contraction of the temperature sensitive body 44 may be provided. Figure 1
FIG. 1 is a sectional view of the cooling water passage 30. This on-off valve 45
Is closed by the temperature-sensing body 44 expanding at the cooling water temperature when the temperature of the throttle body 14 becomes Tα, and the cooling water from the opening / closing valve 45 to the outlet 32 when the temperature of the throttle body 14 becomes Tα−Tβ. The temperature sensitive body 42 is provided so as to contract and open at a temperature. As a result, the same effect as described above can be obtained.

The throttle valve 20 may also be provided with a heater and a temperature sensor. Then, the temperature of the throttle valve 20 is detected, and the temperature difference is calculated from the temperature of the throttle body 14. The throttle body 14 or the throttle valve 20 is heated according to this temperature difference. Thereby, the temperature difference between the body and the valve can be made very small. Therefore, the amount of air leaked from the gap formed between the body and the valve due to the temperature difference can be made minute.

[0035]

With the above-described structure and operation, the throttle valve heating apparatus of the present invention can prevent icing by the temperature of the throttle body adjusted by the temperature adjusting means and reduce the temperature difference between the throttle body and the throttle valve. it can. Therefore, the amount of air leaking from the gap between the throttle body and the throttle valve caused by the temperature difference can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an internal combustion engine intake system including a throttle body heating device according to a first embodiment.

FIG. 2 is a sectional view taken along line I-I of FIG.

FIG. 3 is a view on arrow II in FIG.

FIG. 4 is a flowchart showing the operation of the first embodiment.

FIG. 5 is a time chart showing the temperature of the cooling water, the temperature of the throttle body, and the temperature of the throttle valve when the engine is started (when the intake air temperature is −20 ° C.).

FIG. 6 is a configuration diagram of an internal combustion engine intake system including a throttle body heating device of another embodiment.

FIG. 7 is a flowchart showing the operation of another embodiment.

FIG. 8 is a side view of a throttle body according to another embodiment.

9 is a cross-sectional view of the cooling water passage of FIG.

FIG. 10 is a side view of a throttle body of another embodiment.

11 is a cross-sectional view of the cooling water passage of FIG.

[Explanation of symbols]

 2 ECU 13 Intake air temperature sensor 14 Throttle body 20 Throttle valve 30 Cooling water passage 33 Temperature sensor 34 Passage opening / closing valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area F02M 31/135 31/12 311 Z

Claims (1)

[Claims] 1. A throttle body having a throttle valve for adjusting an intake air amount of an internal combustion engine, a detection means for detecting a temperature of the throttle body, a heating means for heating the throttle body, and a detection means for detecting the temperature. A throttle body for an internal combustion engine, comprising: temperature adjusting means for adjusting the temperature of the throttle body by heating or stopping the heating by the heating means according to the temperature of the throttle body. Heating device.