JPS59136531A - Supercharging pressure controlling apparatus for engine with turbocharger - Google Patents

Abstract

PURPOSE:To enable to control the maximum supercharging pressure with ease and effectively in an apparatus comprising a plurality of turbochargers disposed in parallel with each other, by forming an intake-air relief passage by-passing all of blowers of each supercharger, and providing a supercharging pressure control valve in said intake- air relief passage. CONSTITUTION:A low-speed turbocharger 8 and a high-speed turbocharger 9 are constituted respectively by blowers 8a, 9a disposed in a first and a second branch intake passages 5, 6 formed in an intake passage 2 between an air-flow meter 4 and a throttle valve 7 in parallel with each other and turbines 8b, 9b disposed in a first and a second branch exhaust passages 10, 11 branched from an intermediate portion of an exhaust passage 3. In such an arrangement, an intake-air relief passage 21 is formed for communicating an intake passage 2d located on the downstream side of a joining portion 2a of the above two branch intake passages 5, 6 with an intake passage 2u located on the upstream side of the same. Further, a supercharging pressure control valve 22 is provided at an intermediate portion of the relief passage 21. With such an arrangement, the maximum supercharging pressure is limited by opening the control valve 22 when the supercharging pressure becomes higher than a prescribed value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a plurality of turbo superchargers (liii) comprising a turbine driven by engine exhaust gas and a blower connected to the turbine through a rotating shaft. 2. Description of the Related Art A turbo supercharger in which a turbine and a blower are arranged in parallel in an exhaust passage and an intake passage of an engine is related to an engine.

The technical concept of improving the output performance of Ennon by increasing the pressure of intake air using a turbo supercharger and improving charging efficiency has been well known, and currently, high-speed operation of Ennon is There is a demand for improving output performance by supercharging 1 not only when operating at 1 Fahrenheit, but also when operating at 1 Fahrenheit.

By the way, it is actually extremely difficult to satisfy the requirement 1 with a single turbocharger from the viewpoint of turbocharging efficiency, and it is difficult to satisfy the requirements of item 1 with a single turbocharger. A technical idea has been proposed that attempts to meet these requirements by
(see Japanese Patent Application Laid-open No. 118117/1983).

Additionally, a turbocharger has the characteristic that the supercharging pressure increases approximately in proportion to the increase in engine speed, but increasing the supercharging pressure unnecessarily is not desirable from the standpoint of engine reliability. Instead, it is usually necessary to control the maximum boost pressure so that it does not rise above a predetermined value. Such control of the maximum boost pressure is necessary to prevent knocking not only in the high speed range but also in the low speed range when supercharging is performed in both the low speed range and the high speed range as described in "-". Become.

Therefore, in the case of an ennon in which multiple turbo superchargers are installed in parallel as described above, the turbine and blower of each turbo supercharger must be arranged and connected in parallel to the exhaust passage and intake passage of the engine, respectively. Therefore, the structure of the intake and exhaust passages becomes rather complicated, and in particular, in the type of engine that uses turbo supercharging for low speeds and turbo supercharging for high speeds (switching) as described above, the individual turbo supercharging If you try to control the supercharging pressure on the charger, you will need a device to individually lower the supercharging pressure by 1 degree, such as an intake relief passage that bypasses the turbo supercharging (70A). There are problems in that the passage structure becomes even more complex and its control becomes difficult.

That is, in the above-mentioned type of supercharger A;1 engine, if an intake relief passage is provided for the low-speed turbocharger to limit its maximum boost pressure, then the low-speed turbocharger (or the engine Since the engine is stopped during high-speed operation, an intake relief passage must be provided to limit the maximum boost pressure for high-speed turbocharging.

This situation causes the failure of primary and secondary turbo supercharging (jl).At low speeds when the intake air amount is small, the primary turbo supercharging is used, and at high speeds when the intake air amount increases, both the primary and secondary turbos are used. Supercharging (
There is no essential difference in the type of engine used.

The present invention has been made in view of such problems, and includes:
An intake relief passage that simultaneously bypasses the plurality of blowers and communicates with the upstream intake passage from the intake passage between the engine and the confluence where the intake passages downstream of each blower of a plurality of turbochargers arranged in parallel merge. At the same time, a control valve that responds to the boost pressure is interposed in the intake relief passage, and when the boost pressure rises above a set value, a part of the supercharged air is sent to the intake passage through the intake relief passage. Boost pressure control device for turbocharger 1 inch Ennon, which limits the maximum boost pressure by bypassing two parts, and can effectively and reliably control the maximum boost pressure with a single intake relief passage. )).

Hereinafter, the present invention will be described more specifically based on the illustrated embodiments.
Be happy.

<First example>
3 is an exhaust passage of the engine 1; 11 is an air flow sensor installed at the most upstream part of the intake passage 2 to measure the amount of intake air from the engine 1; and 5.6 is an air flow sensor of the intake passage 2. downstream of valve 1 and above rontre valve 7 i
first and second branch intake passages formed in parallel with t;
, 9 are the 1st. The blowers 8a, 9a interposed in the middle of the second branch intake passages 5, 6 are inserted in the first and second branch exhaust passages 10, 1.1, which are formed by bifurcating the exhaust passage 3 in the middle, respectively. Low-speed and high-speed turbo supercharging (how many) are connected to installed turbines 8b and 9b by rotating shafts 8c+9c.

The low continuous use turbo supercharger 8 is a turbo supercharger that has good efficiency in the low speed range of the engine 1, and when the engine is running at low speed, the first branch exhaust passage 10 and the second
When the exhaust switching valve 12 provided at the branch part 3a with the branch exhaust passage 11 closes the second branch exhaust passage 11, the turbine 81 is activated by the exhaust force flowing down the first branch exhaust passage 10.
) is driven, the blower 8a, which is linked to the rotation of the turbine 81], boosts the pressure of the intake air to provide supercharging when the engine 1 is running at low speed.

Further, the high-speed turbocharger 9 is a turbocharger having good efficiency in the high-speed range of the engine 1, and is connected to the exhaust switching valve 12 and the first turbocharger when the engine 1 is operated at high speed. While the intake switching valve 13 provided at the merging portion 2a of the second branch intake passage 5.6 closes the first branch exhaust passage 10 and the first branch intake passage 5, as shown by the dotted line in the figure,
When the second branch exhaust passage 11 and the second branch intake passage 6 are opened, the exhaust gas flowing down the second exhaust passage 11 drives the turbine 9b, and the blower 9a is interlocked with the turbine 9b.
The pressure of the intake air is increased, and the engine 1 is supercharged via the second branch intake passage 6. In other words, when the engine 1 is operating at high speed, supercharging is performed in place of the high speed turbocharger 53 or the low speed turbocharger 8.

4 uses the output signal of the air flow sensor 4 as a basic human input signal to determine the opening time of the fuel injection valve 15 installed downstream of the intake passage 2 and the rotor valve 7.
A control circuit that controls switching of electromagnetic actuators 16 and 17 provided for the intake switching valves 12 and 13, respectively.
As shown in FIG. 2, the injection pulse generation circuit 18 operates the fuel injection valve 15 during the valve opening time according to the intake air amount detected by the air flow sensor 4. Compare the amount of intake air with the set value, and when the engine 1 is running at low speed, when the intake air volume has not reached the set value, ii
Each actuator 16, 17 is held inoperative, and when the set value t or more is reached, each actuator 16, 17 is operated via the amplifier circuit 20, and each switching valve 12, 13 is set to the state shown in FIG. Switch from the solid line position to the dotted line position.

Again, in FIG. 1, 21 is the first . The downstream intake passage 2d between the confluence part 2a of the second branch intake passages 5 and 6 and the engine 1, and the upstream intake passage 2u downstream of the air 70-sensor... An intake relief passage that simultaneously bypasses and communicates with the blowers 8a and 9a of the machines 8 and 9; 22 is a supercharging pressure control valve that opens and closes a valve seat 23 provided in the middle of the intake relief passage 21; 24 is a supercharging pressure control valve valve 2
2 to the diaphragm 241 via Rondo 2 = l a
25 is a supercharging pressure introduction passage that introduces the supercharging pressure of the downstream intake passage 2d into the positive chamber 24c of the control diaphragm device 24. be. Another chamber 21[d, which is separated from the positive pressure chamber 24c by the diaphragm 24b of the control diaphragm device 24, is formed as an atmospheric chamber communicated with the atmosphere through the atmospheric opening hole 24e.
A coil spring 24f is compressed in d, and the set loads of the coil springs 2 and 4F are set according to the maximum boost pressure that is the control target.

As mentioned above, this maximum boost pressure is basically set in consideration of the reliability of Ennon 1.

With the configuration described in 1-1, the supercharge generated in the low-speed turbo supercharger 8 during low-speed operation of the engine 1, and the supercharge generated in the high-speed turbo supercharge (lower by number 9) in the photometric intake passage 2d during high-speed operation. When the supply pressure reaches the maximum supercharging pressure, the supercharging pressure introduced into the positive pressure chamber 24 (2) of the control Guyar 7 ram device 2'V turns the set load of the coil spring 241, As the diaphragm 24b is displaced and the supercharging pressure control valve 22 is opened, the intake relief passage 21 is continuously communicated with.Therefore, a part of the supercharging air is kept at approximately atmospheric pressure by the intake relief passage 21. ”Second side intake passage 2u
The supercharging pressure in the downstream intake passage 2d is reduced to below the maximum supercharging pressure. Therefore, the supercharging air supplied to the engine 1 is maintained below the maximum supercharging pressure, and the engine 1 is operated satisfactorily without deteriorating its reliability, and exhibits good output performance due to supercharging.

That is, in the first embodiment, the first. Second branch intake passage 5.6
A downstream intake passage 2d between the confluence part 2a and the ennon 1
From, 1 degree speed, high speed turbo supercharger 8, 9 blower 8
By providing an intake relief passage 21 that communicates with the upstream intake passage 2u, a and 9a can be bypassed at the same time. Also, the maximum boost pressure can be controlled effectively and reliably without complicating the passage structure.

In addition, in the first embodiment, the control I1 of the boost pressure control valve 22
The ram device 24 is operated by the supercharging pressure of the downstream side intake passage 2d downstream of the confluence illζ2a, or is operated by the boost pressure of the downstream side intake passage 2d downstream of the confluence illζ2a, or The diaphragm device 24 for controlling the pressure
An exhaust pressure introduction passage 26 that is introduced into the positive pressure chamber 24c is provided in place of the supercharging pressure introduction passage 25, and the exhaust pressure increases as the supercharging pressure increases, or corresponds to the maximum supercharging pressure that is the control target. The supercharging pressure control valve 22 may be opened when the exhaust pressure (set value) reaches a certain level.

<Second Embodiment> Fig. 3 (The second embodiment shown here is basically an equivalent linear
The secondary turbo superchargers 30 and 31 are installed in parallel, and the primary turbo supercharger 30 is used when the engine 1 is operating at low speed with a small intake air amount, and when the engine 1 is operating at high speed when the intake air amount is large.
The present invention is applied to a turbocharger 1τ [engine] that performs primary and secondary turbocharging.

For this reason, the blower downstream of the second branch intake passage 6 in which the secondary turbocharging is provided (the moss), while the check valve 32 is provided, the turbine 3 of the secondary turbocharging
11), an exhaust control valve 33 is provided upstream of the turbine in the second branch exhaust passage 11 in which the secondary turbo supercharging, that is, the control circuit 14 is performed, as shown in FIG.
The intake amount detection signal of the 0-sensor 4 is compared with the set value, and when the intake amount exceeds the set value, the comparison circuit 19 controls the actuator provided for the exhaust control valve 33 via the amplifier circuit 2 (). 34 to open the exhaust control valve 33, thereby opening the second branch exhaust passage 11.

When the second branch exhaust passage 11 is opened, the exhaust gas flowing down this passage 11 drives the turbine 311 to perform secondary turbocharging. The secondary turbo supercharging and the check valve 32 are opened, and the first and second branch intake passages 5,
A downstream intake passage 2d downstream of the merging section 2a where 6 merges.
A composite pressure of the supercharging pressure given by moss primary turbo supercharging () statement 3 and the supercharging pressure given by secondary turbo supercharging t + statement 3] is generated.

Therefore, when the engine is running at low speed, the primary turbo supercharging, and when the engine 1 is running at high speed, the combined supercharging pressure given by the primary and secondary turbo supercharging B'J30, 31 is
When the predetermined maximum boost pressure is reached, the control Guyafram device 24 opens the boost pressure control valve 22 to open the intake relief passage 21 and control the boost pressure to below the maximum boost pressure. It's fun to play.

In other words, in engines with primary and secondary turbo supercharging (¥13, 1.31 turbo supercharging lights), a single intake relief passage 21 is used regardless of whether it is used alone or in combination.
The maximum boost pressure can be controlled effectively and reliably.

Note that, in the same way as described for the first embodiment shown in FIG. 1, in this second embodiment as well, the maximum boost pressure control may be performed based on the exhaust pressure taken out by the exhaust pressure introduction passage 2G. .

Regarding the second embodiment described below, parts that are not different from the first embodiment are designated by the same numbers, and redundant explanation will be omitted.

As is clear from the above description, according to the present invention, it is possible to effectively control the maximum boost pressure of a plurality of turbochargers arranged in row 21E using a single intake relief passage. b. The maximum boost pressure can be controlled without complicating the structure of the intake and exhaust passages.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an engine system showing an fJS1 embodiment of the present invention, FIG. 2 is an explanatory block diagram of the control circuit of FIG. 1, and FIG. 3 is an explanatory diagram of an engine system showing a second embodiment of the present invention.
FIG. 4 is a block diagram of the control circuit of FIG. 2 (1-). Merging section, 2u, 2d... Second section side, downstream intake passage 3...
・Exhaust passage 10, ]1...first and second branch exhaust passages 8, 9...
・Low speed, high speed turbocharger Sa, 9a...Floor, 811. 91]...Turbine, Sc, 9c・
...Rotating shaft 2]...Intake relief passage 22...Supercharging pressure control valve 24...Control Guya 7 ram device 25...Supercharging pressure introduction passage 26...Exhaust pressure introduction passage

Claims (1)

[Claims] (1) Equipped with a plurality of turbo superchargers each consisting of a turbine driven by the exhaust power of the engine and a blower connected to the turbine by a rotating shaft, Engine with a turbo supercharger arranged in parallel in a passage and an intake passage, respectively 1. 2, an intake relief passage is provided which simultaneously bypasses a plurality of blowers from the intake passage between the confluence of the intake passages downstream of each of the blowers and the engine and communicates with the intake passage; A control valve that responds to the boost pressure is installed in the system, and when the boost pressure falls below the set value, a part of the boost air is sent to the intake passage through the intake relief passage. A supercharging pressure control device for a turbocharged engine, characterized in that the maximum supercharging pressure is limited by bypass.