JPH0222211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a secondary air supply device for a V-type engine mainly installed in an automobile.

(Prior art) Devices that supply secondary air to the exhaust system are mainly used in automobile engines to purify the exhaust gas by re-burning harmful components such as carbon monoxide and hydrocarbons in the exhaust gas. It has been adopted. This device communicates the air suction part of an air cleaner or the like with an exhaust manifold or the like through a secondary air supply passage, and is equipped with a reed valve on the passage to prevent the inside of the exhaust system from becoming negative pressure due to exhaust pulsation. At times, the reed valve is opened to draw secondary air into the exhaust system.

Such a secondary air supply device is naturally required in the case of a V-type engine having two banks, but in that case, it is necessary to distribute and supply secondary air evenly to the cylinders of both banks. In addition, V-type engines are bulky and there is little space, especially when installing them in the engine room of a car, so the reed valve in the feeder must be placed in a way that is close to other auxiliary equipment. The engine must be arranged compactly without increasing its size.

By the way, U.S. Patent No. 3,653,212 discloses a V-type engine equipped with a secondary air supply device;
As shown in Fig2, reed valve 23
The lengths of the secondary air supply passages 21 and 22 from the left and right banks to the exhaust passages 13 and 14 are uneven;
Furthermore, the reed valve 23 is provided to protrude below the air cleaner 12, which may take up space for installing other auxiliary equipment.

(Object of the Invention) The present invention is intended to solve the above-mentioned problems when a V-type engine is equipped with a secondary air supply device. In what is being
It is possible to supply secondary air evenly to the cylinders of these banks, and by making effective use of the idle space between both banks, it is possible to prevent the enlargement of the engine and the layout of other auxiliary equipment. It is an object of the present invention to realize a secondary air supply device that can be installed without causing any adverse effects, and that can also provide a cooling effect for intake air, a ventilation effect between both banks, etc.

(Configuration of the Invention) A secondary air supply device for a V-type engine according to the present invention is configured as follows in order to achieve the above object.

That is, two banks each having a plurality of cylinders are arranged at an angle around the crankshaft, and the intake passages extending toward the cylinders of both banks are arranged to intersect at the center of the two banks. In a V-type engine, a secondary air supply device with a built-in reed valve for supplying secondary air to the exhaust passage is provided at the intersection of the intake passages, and an inlet for air intake in the secondary air supply device is open. At least a part of the air intake chamber is formed integrally with the intersection of the intake passage, and a part of the wall of the intake passage at the intersection is shared with a part of the wall of the air intake chamber. According to such a configuration, the reed valve is located in the center of both banks, and secondary air is evenly supplied from the valve to the exhaust passages of both banks, and the reed valve is located in the center of both banks, and the secondary air is evenly supplied to the exhaust passages of both banks. The space in the center of both banks was utilized, allowing reed valves to be installed without increasing the size of the engine.
Also, since a part of the wall of the air intake chamber and a part of the wall of the intersection of the intake passage are shared, the wall is covered by the air flow flowing into the air intake chamber from the air intake inlet. Through this, the air in the intake passage is cooled, and the areas with poor ventilation between the two banks are ventilated.

(Example) Hereinafter, an example of the present invention shown in the drawings will be described.

As shown in FIG. 1, a V-type engine 1 has two banks 5, 5 arranged at a constant angle around a crankshaft 4 by one cylinder block 2 and two cylinder heads 3, 3'. ′
has. These banks 5, 5' are each provided with a plurality of cylinders 6, 6' along the crankshaft direction, and each cylinder 6, 6' is provided with a plurality of cylinders 6, 6', respectively, along the crankshaft direction.
Pistons 7, 7' are fitted into the pistons 6' and connected to the crankshaft 4 via connecting rods 8, 8'. In addition, each of the above cylinder heads 3,
3' is provided with intake ports 9, 9' and exhaust ports 10, 10' which communicate with the cylinders 6, 6', respectively, and an opening of each port to the cylinders 6, 6' is provided with a movable port. Intake valves 12, 12' and exhaust valves 13, 1 opened and closed by valve mechanisms 11, 11'
3', and both cylinder heads 3,
Exhaust manifolds 14, 14' are mounted on the outer side of the exhaust manifolds 14, 14' for merging a plurality of exhaust ports 10, 10' in each of the exhaust manifolds 14, 14'. Here, the second
As shown in the figure, both exhaust manifolds 14 and 14' are guided to the rear of the engine 1, and catalytic converters 15 and 15' are installed respectively. is open to the public.

On the other hand, in the space between the two banks 5, 5' or above both banks 5, 5', there is an intake air which supplies combustion air to the cylinders 6, 6' through the above-mentioned intake ports 9, 9'. A device 17 is provided. As shown in FIGS. 1 and 2, this intake device 17 includes two surge tanks 18, 18' which are disposed above the banks 5, 5' substantially in the direction of the crankshaft and have one end closed. A plurality of surge tanks 18 and 18' are branched out from each other and are provided so as to alternately intersect with each other toward intake ports 9' and 9 in banks 5' and 5 located on opposite sides. branch passage 1
9, 19'. The open ends of both surge tanks 18, 18' are communicated with each other by a communication pipe 21 extending in a direction substantially perpendicular to the crankshaft direction via throttle valves 20, 20'. An air cleaner 23 is connected to one end of the air cleaner 21 via an air flow meter 22 .

Here, the two surge tanks 18, 18'
and a plurality of branch passages 19, 19 branched from both surge tanks 18, 18'. 1
9', two surge tank parts 24, 24' integrally formed with the upstream part 9', and branch passages 19,
The downstream part of the manifold part 19' is composed of intersecting manifold parts 25 provided alternately and intersectingly. The downstream portions of the branch passages 19, 19' in the intersecting manifold portion 25 face the intake ports 9', 9 of the cylinder heads 3', 3 communicating therewith, and are provided with fuel injection nozzles 26, 26, respectively. is installed, and a fuel distribution pipe 27,
Fuel is distributed and supplied to each nozzle 26, 26' via 27'.

As shown in an enlarged view in FIG. 3, a secondary air supply device 30 is provided on the upper surface of the intersecting manifold portion 25 of the intake device 17. This secondary air supply device 30 is provided integrally with the intersecting manifold section 25 along a valley-shaped depression where the upper surfaces of the constituent walls of the branch passages 19 and 19' extending in opposite directions in the intersecting manifold section 25 intersect. an air intake chamber 31 with an open upper surface; and a valve case 32 attached to cover the upper surface of the chamber 31.
and a reed valve 33 built into the case 32.
and a filter 34, and two secondary air supply pipes 35 connected to both sides of the case 32, respectively.
35'. The lower part of the side wall of the air intake chamber 31, that is, the cross manifold part 2
An air inlet 31a to the intake chamber 31 is provided at a position directly above the upper wall of the branch passages 19, 19' at 5, and as shown in FIG. It is guided toward the exhaust manifolds 14 and 14' in the banks 5 and 5', respectively, and is branched into a plurality of pipes, and then connected to the exhaust manifold 1.
4 and 14'. Also,
The reed valve 33 has a through hole 36a provided in a partition plate 36 that partitions the inside of the air intake chamber 31 and the inside of the valve case 32. The lead 37a opens the through hole 36a when the inside of the case 32 becomes negative pressure. Here, in order to prevent damage to the lead 37a due to excessive opening operation, the lead 37a is
A stopper member 37b is provided on the opening side of 7a.

In this embodiment, as shown in FIG. 2, an exhaust gas recirculation passage 38 branched from one exhaust manifold 14' is provided along the upper surface of the intersecting part of the intersecting manifold part 25 via an exhaust recirculation control valve 39. The exhaust gas is connected to the branch passage 40, and further communicated with each branch passage 19, 19' through a through hole 41, as shown in FIGS. It's summery.

According to the above configuration, the air taken in from the air cleaner 23 passes through the air flow meter 22 and then branches into two directions, one path passing through the throttle valve 20 and flowing into the surge tank 18 on one side, and the other path flowing into the surge tank 18 on one side. is the communication pipe 21 and the throttle valve 2
0' into the surge tank 18' on the other side, and further branched from the surge tanks 18, 18' into a plurality of branch passages 19, 19', respectively, located on opposite sides. bank 5',
The air is drawn into the cylinders 6', 6 through respective intake ports 9', 9 at 5.

Further, the exhaust gas generated in the cylinders 6, 6' of both banks 5, 5' is transferred to exhaust manifolds 14, 1, respectively.
4′, the catalytic converter 15,1
5', and is further discharged to the outside through a muffler 16.

However, in the exhaust manifolds 14, 14', so-called exhaust pulsation occurs due to the intermittent discharge of exhaust gas from each cylinder 6, 6', and the interior of the manifolds 14, 14' periodically oscillates. It becomes a negative pressure state. Therefore, the manifold 14,1
4' through secondary air supply valves 35, 35', the manifolds 14, 14'
When the inside becomes negative pressure, the reed valve 33 opens,
Air is taken in from the outside through the air intake chamber 31, and is supplied into the exhaust manifolds 14, 14' via the filter 34, reed valve 33, and the secondary air supply valves 35, 35'. This secondary air recombusts carbon monoxide, hydrocarbons, etc. in the exhaust gas, or promotes reactions in the catalytic converters 15, 15', thereby purifying the exhaust gas.

In this case, the reed valve 33 or the valve case 32 has a valley-like shape where the branch passages 19, 19' extending in opposite directions from the upper surface of the intersecting manifold part 25 in the center of both banks 5, 5' intersect. It is installed in a recessed area, making effective use of space that could not previously be used for other purposes. In addition, the reed valve 33
From the exhaust manifold 14 of banks 5, 5' on both sides,
Since the distance to 14' is the same, both banks 5,
Secondary air is evenly supplied into the exhaust system 5'.

Furthermore, the air intake chamber 31 is integrally provided on the upper surface of the intersecting manifold section 25, and a part of the wall constituting the air intake chamber 31 and the branch passages 19, 1 are connected to each other.
A part of the constituent wall of room 9' is shared, and
Since the inlet 31a to the branch passage 1 is provided at a position directly above the upper wall of the branch passages 19, 19', and secondary air is sucked in along the upper wall, the inlet 31a to the branch passage 1
The intake air passing through 9, 19' is cooled by this flow of secondary air, thereby improving the filling efficiency of the intake air. Further, due to this flow of secondary air, the area with poor ventilation sandwiched between both banks 5 and 5' is forcibly ventilated.

(Effects of the Invention) As described above, according to the present invention, in a V-type engine that has two banks and is provided such that the intake passages extending to the cylinders of both banks intersect at the center of the two banks. , a secondary air supply passage with a built-in reed valve for supplying secondary air to the exhaust passage is provided at the intersection of the intake passage, which has rarely been used in the past in this type of V-type engine. The space between the two banks is effectively utilized, and the reed valve can be installed without increasing the size of the engine or affecting the layout of other auxiliary equipment. Further, secondary air can be evenly supplied to the cylinders of both banks, and the exhaust gas is effectively purified. Furthermore, since at least a part of the wall of the air intake chamber in which the air intake inlet forming the secondary air supply device is opened is shared with a part of the wall of the intersection in the intake passage, The flow of air drawn into the air intake chamber from the inlet cools the air in the intake passage, improving the intake air filling efficiency and providing ventilation between the two banks, which have poor air permeability.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional rear view of the entire engine, FIG. 2 is a plan view of the main parts of the engine including the exhaust system, and FIG. 3 is a diagram of FIG.
FIG. 2 is an enlarged longitudinal cross-sectional rear view of the main part cut along a line. 1...Engine, 4...Crankshaft, 5,
5'... Bank, 14, 14'... Exhaust passage (exhaust manifold), 19, 19'... Intake passage (branch passage),
30...Secondary air supply device, 31...Air intake chamber, 3
1a...Inlet, 33...Reed valve, 35, 35'
...Secondary air supply passage.

Claims (1)

[Claims] 1 two banks each having a plurality of cylinders are arranged at an angle around the crankshaft,
In addition, in a V-type engine in which intake passages extending toward the cylinders of both banks are provided so as to intersect at the center of both banks, a secondary air supply system with a built-in reed valve that supplies secondary air to the exhaust passage is used. a device is provided at the intersection of the intake passages, at least a part of the air intake chamber in which the air intake inlet of the secondary air supply device is opened is integrally formed with the intersection of the intake passages; A secondary air supply device for a V-type engine, characterized in that a part of the wall of the intake passage of the above-mentioned air intake chamber is shared with a part of the wall of the air intake chamber.