JPS63227916A - exhaust manifold cooling system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an exhaust manifold cooling device that efficiently cools an exhaust manifold by water injection.

[Conventional technology] In order to improve the durability of the exhaust manifold itself and the heat resistance of the supercharger, or to reduce the exhaust temperature and reduce the fuel OT (O
ver Temperature) reduction in volume increase, WOT
(Wide 0 Pen Throttle) It is known that cooling the exhaust manifold is effective in reducing fuel consumption, improving performance such as engine output torque, and suppressing knocking.

As a forced cooling method for the exhaust manifold,
A method using air cooling is also considered, similar to the exhaust pipe cooling described in Publication No. 7118@ and Japanese Utility Model Application Publication No. 61-78213, but since the cooling capacity is limited in the case of air cooling, great effects cannot be expected.

Various methods have been proposed as highly efficient cooling methods that are comparable to water cooling.

For example, Utility Model Application Publication No. 61-21814@publication, Utility Model Application No. 6'
Japanese Patent No. 1-134513 discloses a structure in which an A-ta jacket is provided around the outer periphery of an exhaust manifold, and cooling water is allowed to flow through the A-ta jacket. Although not intended for cooling the exhaust manifold, there is also known a structure in which water is showered on the outer wall of the cylinder of the engine (Japanese Utility Model Publication No. 56-138113). A structure is also known in which a flow of cooling air containing fine water droplets is applied to the entire engine with cooling fins (Japanese Unexamined Patent Publication No. 55-60618).

However, in the structure shown in Japanese Utility Model Application No. 61-21814 and Japanese Utility Model Application No. 6"j-134513, cooling water is filled in the four-way jacket 1 formed on the outer periphery of the exhaust manifold. As a result, the heat capacity of the exhaust manifold increases due to the presence of water, which worsens engine warm-up.In addition, in the case of the water-cooled structure described above, the amount of heat absorbed by the exhaust manifold is transferred to the engine cooling water. There is also the problem that the radiator needs to be used to release the gas into the atmosphere, which means that the radiator needs to be larger.

Furthermore, although the structure shown in Utility Model Application Publication No. 56-138113 is not intended for exhaust manifolds, even if such In were applied to the water jacket around the exhaust manifold, it would simply prevent water showers. There is a problem in that the water shower is not uniformly distributed within the jacket and therefore the exhaust manifold is not uniformly cooled.

In order to solve the above-mentioned problems, although the application has not yet been published, the applicant has proposed a method in which atomized water from a water injection nozzle is introduced into the water jacket formed around the outer periphery of the exhaust manifold. By utilizing the latent heat of vaporization of the water spray, the water spray can be uniformly distributed within the water jacket around the exhaust manifold without particularly increasing the heat capacity of the exhaust manifold, and the exhaust manifold can be uniformly and efficiently A cooling device has been proposed. In particular, by introducing a part of the supercharged air into the A-ta jacket and introducing water spray along with the flow, the spray can be uniformly dispersed within the A-taji qp cut. Uniform cooling is possible.

[Problems to be Solved by the Invention] However, in the exhaust manifold cooling device previously proposed by the applicant, when the engine is stopped (when the engine key is turned off)
Since the water injection nozzle for cooling the exhaust manifold was not activated, after the engine stopped, the water spray supplied to the engine jacket evaporated and disappeared.
The exhaust manifold was not to be forced to cool down after the engine was stopped. Therefore, the problem remains that the temperature inside the engine room may rise considerably due to the heat radiated from the exhaust manifold, which has a large heat capacity due to the double pipe structure of the engine jacket. . A high temperature in the engine room may cause vapor lock in the fuel supply system, which may lead to problems such as poor restartability. Additionally, if the engine is stopped while the exhaust manifold is still hot, the water injection nozzle may tend to overheat due to heat transfer from the exhaust manifold wall or even from the engine side, causing problems with its durability and reliability. left behind.

The present invention relates to an improvement of the exhaust manifold cooling device previously proposed by the applicant, and an object of the present invention is to make it possible to optimize the temperature of the exhaust manifold even after the engine is stopped.

[Means for Solving the Problems] The exhaust manifold cooling device of the present invention which meets this objective has two four-way V7 holes formed around the exhaust manifold and one inside the A-way jacket 1-. In an exhaust manifold cooling device having a water injection nozzle capable of injecting water in the form of atomized water toward the exhaust manifold, an exhaust temperature sensor IJ is provided in the U1 air manifold, and the water injection nozzle is activated based on a signal from the exhaust temperature sensor IJ. The water injection nozzle is connected to a control device that can control the water injection nozzle during engine operation and after the engine is stopped.

[Function] In such an exhaust manifold cooling device, during engine operation, atomized water from the water injection nozzle is introduced into the water jacket around the exhaust manifold, and Δ
- The high temperature exhaust manifold is efficiently cooled mainly by the latent heat of vaporization when the water spray is vaporized by the heat of the exhaust manifold. By detecting the actual exhaust gas humidity at that time by the exhaust temperature sensor, the actual engine condition and catalyst activation condition are accurately detected, and based on that, the water injection ω is controlled to be optimal. .

Therefore, even after the engine has stopped, the humidity of the exhaust manifold is detected by the exhaust temperature sensor 1, and the exhaust manifold is maintained at an appropriate temperature, that is, good restartability, and there is no adverse thermal effect on the water injection nozzle. Water is injected by the water injector nozzle via the control device until the temperature is reached. Therefore, after the engine is stopped, the exhaust manifold is forcibly cooled down to the above-mentioned appropriate temperature within a short time, improving restartability and
The durability and reliability of the water injection nozzle are ensured.

[Embodiments] Preferred embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 shows a cooling device for an exhaust manifold according to a first embodiment of the present invention. In the figure, 1 is the engine, 2
3 is a cylinder block, 3 is a cylinder head, 4 is an intake manifold connected to the intake boat 5, and 6 is an exhaust manifold connected from the exhaust boat 7, respectively. A supercharger 8 is attached to the exhaust manifold 6. Exhaust scum is introduced into the turbine 9 of the supercharger 8, and air taken in through the air flow meter 101 and the intake duct 11 is compressed by the compressor 4J12. The compressed air is sent as supercharged air to the intercooler 14 via the intake duct 13, and from the intercooler 14 to the intake duct]・1
5 to the intake system. 16 indicates a small valve.

A two-way Vket 17 is provided on the outer periphery of the exhaust manifold 6, covering almost the entire area thereof.

The A-taper jacket 17 is formed by making the exhaust manifold 6 into a double pipe structure. A supercharged air introduction passage 18 is provided between the turbo jacket 17 and the intake duct 15 to allow communication between the two. can now be introduced. A check valve 19 is provided at the connection portion of the supercharged air introduction passage 18 to the intake duct 15 to prevent backflow of air from the supercharged air introduction passage 18 side to the intake duct 15 side.

A water injection nozzle 20 is provided near the water jacket 17 of the supercharged air introduction passage 18 for spraying water in the form of a spray into the engine jacket 17. This water injection nozzle 20 is connected to an ECU 21 as a control device and is operated based on a signal from E (JJ 21). It has the same structure and function as the 17-person jacket, and sprays water in a controlled manner into the 17-person area of the jacket.

A drain pipe 22 is connected to the lower part of the Δ-tajitokket 17 as a discharge passage for discharging water together with the supercharged air from the Δ-tajitokket 17.

The drain pipe 22 is provided with a cold N nozzle 23,
One quarter jacket is designed to condense 17 gallons of water spray using air cooling. The lower end of the drain pipe 22 is connected to a drain tank 24, air and water from the drain pipe 22 are separated in the upper space of the drain tank 24, and water is stored in the lower part. Drain tank 24 is connected to pump 25, and drain tank 2 is connected to pump 25 by pump 25.
4 is circulated again to the water injection nozzle 20 via a water return pipe 26. Also, 27
28 indicates a separate full plate, and 28 indicates an air/water separation filter, and the drained supercharged air is passed through the return pipe 29.
The air is returned to the upstream side of the compressor tree 12 of the supercharger 8 via the air.

Each uF air manifold 6 is collected at an exhaust manifold collecting section 30 and connected to an exhaust pipe 31. exhaust pipe 31
A catalytic converter 32 is installed in the middle of the exhaust manifold or immediately after the exhaust manifold gathering part 30, and a catalyst Is (not shown) for exhaust gas purification is installed in the catalytic converter 32.
is accommodated.

The exhaust manifold collecting section 30 is equipped with an exhaust temperature sensor 33 (for example, a sensor) that detects the humidity of the υF gas passing through the exhaust manifold collecting section 30 itself or inside. An exhaust temperature sensor 34 (for example, 4J-Mister) is also provided at a position immediately after the catalyst. Detection signals from these exhaust temperature sensors 1) 33 and 34 are sent to the ECtJ21. [In ECU21, the second
As shown in the figure, the signals from the exhaust gas temperature sensors 33, 34 are input to comparators 35, 36, and are compared with preset temperatures in each comparator 35, 36. In the comparator 35, the set temperature for comparison is, for example, 850'C.
6 is set to 800'C, for example. Comparator 3
The signal from 5.36 is input to the OR circuit 37, and when the signal from either one or both of the exhaust temperature sensors 1 and 33.34 exceeds the above set value, the signal from the OR circuit 37
An exhaust temperature rise signal is issued to U38. An operation control signal is sent from the CPU 38 to the water injection nozzle 20 via a suitable signal processing circuit. Further, in this embodiment, a fuel cut signal 39 is also input to the ECU 21, and the operation of the water injection nozzle 20 can also be controlled based on the input signal 39.

Exhaust 41? The circuit from the engine 33 to the comparator 35 includes a relay 41 that is activated in conjunction with the ignition switch 40, and the relay 41 is activated when the ignition switch 40 is on (when the engine is running). It constitutes a circuit that sends No. 13 from the temperature sensor 33 to the comparator 35, and when the ignition switch 40 is off (after the engine has stopped), the A/D converter 42 (analog-digital converter) built into the ECU 21 is connected. The detected temperature signal from the exhaust temperature sensor 33 is sent to the CPU 38/\ via the exhaust temperature sensor 33. When the ignition switch 40 is turned off, the ECU 2
However, in this device, the power supply to the battery power supply 4 is turned off for a certain period of time via the timer 43 by using the old relay.
4 can be connected. The time set by the timer 43 is sufficient for cooling the exhaust manifold, which will be described later.

The operation of the embodiment device configured as described above will be explained.

First, if J3 is running while the engine is running, the water injection nozzle 20
The water injected from the supercharged air introduction passage 18h rides on the flow of supercharged air introduced from the supercharged air introduction passage 18h), becomes a spray, and is uniformly dispersed within the A-taper jacket 1-17. and,
The latent heat of vaporization efficiently removes heat from the exhaust manifold 6, is cooled and condensed in the drain pipe 22, and is stored in the drain tank 24. The accumulated water is again sent to the water injection nozzle 20, and the supercharged air that has been passed through the air/water valve head 1 is returned to the upstream side of the compressor 12.

In such a system, the water injection ω from the water injection nozzle 20 is controlled as follows depending on the state of the engine.

As shown in the system on the left in FIG. It is determined whether or not the value has increased more than the set value. The exhaust temperature is
33. If the value is less than the set value in any of 33 and 34,
Since the warm-up has not been sufficiently performed and the catalyst has not reached a sufficient activation temperature, the process proceeds to A and the driving of the water injection nozzle 20 is stopped. At this time, the jet pulse of the water jet nozzle 20 is stopped at J shown in FIG. 4.

When either exhaust temperature exceeds the set value, or when both exceed the set value, the process proceeds to step 102, and )1
- Determine whether or not a nil cut is in progress.

In step 102, it is determined whether or not the fuel cup is in the 1st to 1st range. If the fuel cup is in the 1st to 1st state, the process proceeds to B, where the engine stops after several intermittent injections as shown in FIG. D) Preventing temperature drop when returning from fuel cut. Next, if the fuel is not being cut, C
Then, as shown in FIG. 6, the fuel is injected intermittently several times and then continuously. This prevents cracking and distortion of the exhaust manifold (normal shock) caused by rapid cooling due to continuous injection, compared to the case of rapid continuous injection. Note that the ON and OFF time settings for intermittent watch division are determined by suitability.

In this way, in the device of the present invention, the amount of water jetted from the water jet 6J nozzle 20 is controlled based on the actually detected υ1 temperature, so that the amount of water jetted from the water jet 6J nozzle 20 is controlled accurately to the desired amount in accordance with the actual engine condition at that time. Cooling of the exhaust manifold 6 is carried out.

Next, the case after the engine is stopped, that is, when the ignition switch 40 is turned off, will be explained using the system on the right side of FIG.

As mentioned above, even when the engine is stopped, the ECU 21 is activated for a certain period of time by the timer 43, and the signal from the exhaust temperature sensor 33 is sent to the CPU 38 via the A/D converter 42.

If it is determined in step 103 that the ignition switch 40 is off, the process moves to step 104 and the cooling water circulation pump 25 is driven. Then, the process moves to step 105, where υ [temperature hint 1] is drawn on the exhaust manifold gathering part.
If the exhaust gas temperature measured by step 33 is, for example, 200° C. or higher, the cooling water injection nozzle 20 is caused to continuously inject water as shown in FIG. 7 in step 106, and the process returns to step 103. If the exhaust gas temperature is less than 200°C, the process moves to step 107, where it is determined whether cooling has been performed to a temperature T°C (<200°C) at which restart failure and water injection nozzle damage due to overheating will not occur. If it is higher than 1℃, step 1
At step 08, intermittent injection is performed in a pattern as shown in FIG. 8, and the process returns to step 103. When T'C is reached, the process moves to step 109, where the water injection nozzle 2 () and the cooling water circulation pump 25 are stopped, and the loop is ended.

In this way, even after the engine has stopped, water is injected from the water injection nozzle 20 according to the temperature of the exhaust manifold 6, and the exhaust manifold 6 is forcibly is given a cold IJJ.

This cooling is done first in the engine room and in the water injection nozzle 2.
In order to prevent the temperature from rising rapidly, the temperature is rapidly cooled by continuous injection until the temperature drops to 200° C. or lower, for example. When the temperature drops below 200°C, V due to rapid cooling
- From the viewpoint of suppressing malshock, the fuel is gradually cooled to a predetermined temperature T° C. by intermittent injection. Cooling to below 1℃
This is not necessary since it may lead to overcooling, which may actually impair the engine's ability to warm up when restarted.

In addition, in the above-mentioned water injection pattern after stopping the engine, if there is no need to take legal shock into account, it is preferable to cool down to the predetermined temperature T'C degrees as quickly as possible. A pattern of only continuous injection may be used.

Second Embodiment Next, FIG. 9 shows a second embodiment of the present invention. In this embodiment, one A from the water injection nozzle 20 during engine operation is
- Relying on natural intake air to assist in supplying water spray into the jacket 17 without using supercharged air. That is, instead of supercharged air, running wind from outside the vehicle is introduced from the outside air intake duct 51 through the tip of the water injection nozzle 20 into the A-taper jacket 17 of the exhaust manifold 6 to cool the exhaust manifold 6. The high temperature air and water jetted from the water jet nozzle 20 pass through the drain pipe 22 to the tank 2.
It is stored in 4. Baffle plate 27, filter 28
The water vapor that is not separated is led to the combustion chamber through a return pipe 52 and a duct 54 from an air flow meter 53, and is used to reduce knocking at full load. Since the groove configurations other than the natural intake and return pipe 52 are the same as in the first embodiment, the same reference numerals as in FIG. 1 are given to the parts corresponding to those in FIG. 1, and a description thereof will be omitted.

Even with such a naturally aspirated structure, the exhaust manifold 6 is forcibly cooled to a predetermined temperature within a short period of time by injecting water under the same control as described above after the engine is stopped. Other operations are similar to those in the first embodiment.

[Effects of the Invention 1] As explained above, when the exhaust manifold cooling device of the present invention is used, in the device that injects water toward the inside of the A-taji (/kerato) formed on the outer periphery of the exhaust manifold, even after the engine is stopped, The exhaust manifold can be cooled down to a predetermined temperature or below in response to a signal from the exhaust temperature sensor that detects salt in the exhaust manifold, so that the exhaust manifold can be forcibly cooled down to the optimum temperature range for a short period of time after the engine has stopped. This will prevent the water injection nozzle from overheating, preventing the engine room from becoming too hot, preventing vapor lock phenomena in the fuel supply system, and maintaining good restartability. By preventing this, it is possible to improve the durability and reliability of the nozzle.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of the υF air manifold cooling system according to the first embodiment of the present invention, Fig. 2 is a block diagram of the system shown in Fig. EC (J) control flow diagram of the device shown in Fig. 4 to 6 do not show each control pattern during engine operation of the water injection nozzle in Fig. 1; and Fig. 8 is a relationship between injection pulses and time according to each control pattern of the water injection nozzle in Fig. 1 after the engine is stopped, and Fig. 9 is an overall diagram of the exhaust manifold cooling system according to the second embodiment of the present invention. The configuration diagram is as follows: 1... Engine 2... Cylinder block 3...
・・・・・・・・・Cylinder head 4・・・・・・・・・
...Intake manifold 6...Exhaust manifold 8...Supercharger 9... Turbine 10... Air flow meter 11.
・・・・・・・・・Suction duct 1-12・・・・・・
・・・・・・Comprehension 14・・・・・・・・・・・・
・Intercooler 15...Intake duct 17...4-taper jacket 1
8......Supercharged air introduction passage 19...
・・・・・・・・・Check valve 20・・・・・・・・・Water injection nozzle 21...
・・・・・・・・・ECU 22・・・・・・・・・・・・Drain pipe 23...
......Cooling fin 24...
...Drain tank 25...Pump 26...Water return pipe 27.
......Baffle plate 28...
・・・・・・・・・Filter 29・・・・・・・・・・・・
・Return pipe 30・・・・・・・・・Exhaust manifold gathering part 31・・・・・・・・・Exhaust pipe 32・・・・・・・・・Catalytic converter 33.3
4... Exhaust temperature hint 35.36...
Comparator 37......OR circuit 38...
・・・・°・・・CPU39・・・・・・・・・・・・
Fuel cut signal 40...Ignition switch 41...Relay 42...A/D converter 43・
...... Timer 51 ...... Air intake duct 52
......Return pipe 53...
......Air flow meter 54...
...Dow 1 - Patent applicant Toyota Motor Corporation Time Figure 9

Claims (1)

[Claims] (1) In an exhaust manifold cooling device that has a water jacket formed around the exhaust manifold and a water injection nozzle capable of injecting atomized water into the water jacket, an exhaust temperature sensor is provided in the exhaust manifold. , wherein the water injection nozzle is connected to a control device capable of controlling water injection by the water injection nozzle both during engine operation and after the engine is stopped, based on a signal from the exhaust temperature sensor. Device.