JPH0429059Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention has turbochargers with large and small capacities arranged in parallel, and by switching the operation of these turbochargers, Large and small-capacity turbocharged engines that can effectively supply air for all engine conditions, including high-speed, high-load regions, startup, and low-speed, high-load regions where supercharging is difficult to achieve. When large and small capacity turbochargers are operated together at high speeds and high loads, the exhaust gas passages of the large and small capacity turbochargers are adjusted to balance the boost pressures of the turbocharger compressors. The present invention relates to a turbocharged engine in which the filling efficiency of air supply to the engine is improved by controlling the switching direction and opening area of a switching valve attached to a partition wall.

Conventional technology In the past, turbo superchargers with large and small capacities were arranged in parallel, and by switching the operation of these turbo superchargers, the total Regarding engines with large and small capacity turbochargers that can effectively supply air in accordance with all engine conditions, there is an idea described in previously filed Utility Model Application No. 61-27843.

The above idea consists of large and small capacity turbochargers arranged in parallel, an exhaust passage with an on-off switching valve interposed between the turbine of each turbocharger and the engine, and An air supply passage with a check valve interposed therebetween is provided to supply air to the engine from each compressor to be operated, and as a result of switching the on-off switching valve on and off, only the small capacity turbo supercharger The startup and low-speed, high-load region is achieved by operating the large-capacity turbo supercharger alone, the medium-speed, high-load region is achieved by operating the large-capacity turbo supercharger alone, and the high-speed, high-load region is achieved by operating both the large and small-capacity turbo superchargers. It was a turbocharged engine that was capable of supplying air in three stages that matched the engine speed and load.

Below, a conventional turbocharged engine will be explained based on Fig. 1. 1' is a large capacity turbocharger, 2' is a small capacity turbocharger, and these large and small capacity turbochargers are Superchargers are arranged in parallel, and the large-capacity turbocharger 1' rotates a turbine 5' with exhaust gas flowing from the engine 3' through the on-off switching valve 4', and a compressor 6' that operates in conjunction with the turbine. is operated, a large amount of air is supplied to the engine 3' via the check valve 7', and
Also in the small capacity turbocharger 2', the compressor 1 rotates the turbine 9' with the exhaust gas flowing from the engine 3' through the on-off switching valve 8'.
0' was operated, and a small volume of air was supplied to the engine 3' by the compressor 10' via the check valve 11'.

The intake air matched to the engine speed and load condition is made possible by switching the on-off switching valves 4' and 8', and the rotation of the turbine by the exhaust gas from the engine 3' becomes a small-capacity turbo supercharger. When only 2' is selected, the vehicle is operated in the low speed and high load range when starting the vehicle, and when only the large capacity turbocharger is set to 1', the engine is operated in the medium speed and high load range.
Furthermore, when both the large-capacity turbocharger 1' and the small-capacity turbocharger 2' were rotated, they were operated in a high-speed, high-load region.

When the operating ranges of the above-mentioned large- and small-capacity turbocharged engines with respect to the engine speed Ne and load torque T are illustrated, they are divided into three stage ranges as shown in Figure 2, including the start-up and low-speed high-load ranges. The region "Small" is operated only with a small capacity turbocharger, the region "Large" is a medium speed high load region is operated only with a large capacity turbocharger, and the region is a high speed high load region. "Small + Large" was operated with both large and small capacity turbo superchargers. The supply of air matched to the engine speed and load is carried out by switching on/off switching valves 4' and 8' of the turbo supercharger, which have large and small capacities.

Problems that the invention aims to solve: However, in conventional engines with large and small capacity turbochargers, the air supply characteristics of these turbochargers are different, so in high-speed and high-load regions, large and small When both capacity turbochargers are operated together, each boost pressure of the compressor of both turbochargers is deformed independently, and the engine 3'
Depending on the rotation speed or load condition, pressure differences may occur between each boost pressure, making it difficult to supply air to the engine smoothly and creating an unbalanced supply pressure. There were disadvantages such as lowering the charging efficiency for the entire engine.

Therefore, the present invention aims to equalize the boost pressures of the compressors of the large and small capacity turbochargers when both large and small capacity turbochargers are operated at high speed and high load. The purpose is to improve the charging efficiency of large and small capacity turbo superchargers to the engine by controlling the switching direction and opening area of the switching valve attached to the partition wall of each exhaust gas passage. .

Means for Solving the Problems The present invention has large and small capacity turbochargers arranged in parallel, and each turbocharger is switched on and off by the on-off switching valve. load area,
In engines equipped with large and small capacity turbo superchargers, which enable supply air that matches engine conditions such as medium speed and high load regions and high speed and high load regions, large and small capacity turbo superchargers are used in high speed and high load regions. When both are operated, the switching direction and opening area are controlled according to the pressure difference between the boost pressures generated by the compressors of these turbochargers, and a part of the exhaust gas in the exhaust gas passage of the large-capacity turbocharger is controlled. By adjusting and diverting a part of the exhaust gas from the exhaust gas passage of the small capacity turbocharger to the exhaust gas passage of the small capacity turbocharger, or to the exhaust gas passage of the large capacity turbocharger, A turbocharged engine characterized in that a switching valve that operates to equalize both boost pressures is attached to both exhaust gas passage partition walls on the turbine side from the on-off switching valve of the large and small capacity turbocharger. It is.

Effects Therefore, in a turbocharged engine in which large and small capacity turbochargers are arranged in parallel,
Exhaust gas from the engine is switched by the on-off switching valve of each turbo supercharger to control the rotation of the turbine of each turbo supercharger, and the rotation of the turbine of each turbo supercharger is controlled. When supplying air according to engine conditions such as load range, when both large and small capacity turbochargers are operating in high speed and high load ranges, both boosts of the compressors of these turbochargers are applied. The switching valve that controls the switching direction and opening area according to the pressure difference and operates to equalize both boost pressures is a partition wall for both exhaust gas passages on the turbine side of the on/off switching valve of a large and small capacity turbocharger. attached to.

Therefore, if the boost pressure caused by the compressor of the large-capacity turbocharger becomes greater than the boost pressure caused by the compressor of the small-capacity turbocharger, the switching valve will control the exhaust gas passage of the large-capacity turbocharger. A part of the gas is diverted to the exhaust gas passage of the small capacity turbocharger, increasing the exhaust gas flow rate in the exhaust gas passage of the small capacity turbocharger, and reducing the amount of exhaust gas in the exhaust gas passage of the large capacity turbocharger. It operates by reducing the flow rate so that the boost pressures of both compressors are balanced. Conversely, if the boost pressure from the compressor of the large-capacity turbocharger becomes smaller than the boost pressure from the compressor of the small-capacity turbocharger, the switching valve will control the exhaust gas in the exhaust gas passage of the small-capacity turbocharger. A portion is diverted to the exhaust gas passage of the large-capacity turbocharger, and operates to balance the boost pressures of both compressors.

Embodiment Hereinafter, an embodiment of the present invention will be explained based on the drawings.As shown in FIG. 3, 1 is a large capacity turbocharger, 2 is a small capacity turbocharger, The large and small capacity turbochargers are arranged in parallel, and when the turbine 9 of the small capacity turbocharger 2 is rotated by the exhaust gas 14 from the engine, the compressor 10 that is linked to the turbine 9 of the small capacity turbocharger 2 rotates.
When the turbine 5 of the large-capacity turbocharger 1 is rotated, the associated compressor 6 operates to supply air 15 to the engine through the air supply passage 7a. As a result, air is supplied 16. Large and small capacity turbochargers 1 and 2
Each of the turbines 5, 9 is provided with on-off switching valves 4, 8 for switching the inflow of the exhaust gas 14 into the turbines 5, 9.
4a, 14b, these on/off switching valves 4,
By switching 8, the large and small capacity turbochargers are operated, and only the small capacity turbocharger 2 is operated to supply air to the engine at startup and in low speed and high load areas, and the large capacity turbocharger 1 is operated. Supply air to the engine in the medium-speed and high-load range by only operating the pump. Furthermore, by operating both the large and small capacity turbochargers 1 and 2, air can be supplied to the engine in the high speed and high load range.

However, these large and small capacity turbochargers 1,
The air supply characteristics of the two turbochargers are different, and when both the large and small capacity turbochargers are operated together in the above-mentioned high speed and high load region, the boost pressures generated by the compressors 6 and 10 of both turbochargers are respectively Since they change independently, the exhaust passages 14a and 14 of large and small capacity turbochargers vary depending on the pressure difference between both boost pressures.
The switching direction and opening area of the switching valve 12 attached to the partition wall 14c of b are controlled, and by equalizing the boost pressures of the compressors of the large and small capacity turbochargers, large and small capacity turbo supercharging for the engine is achieved. The filling efficiency of the machine is improved.

That is, when both the large and small capacity turbochargers 1 and 2 are operated, if the boost pressure P ₁ in the air supply passage 7a of the large capacity turbocharger 1 is the same as that of the small capacity turbocharger 2. If the boost pressure P ₂ of the air supply passage 11a becomes larger and a pressure difference of ΔP=P ₁ −P ₂ occurs, the diaphragm 13 of the actuator 13
a is displaced based on the pressure difference ΔP, and each exhaust gas passage 14a, 14 of the large and small capacity turbochargers 1, 2
The switching valve 12 attached to the partition wall 14c of b rotates in the direction A shown in the figure, so that a part of the exhaust gas in the exhaust gas passage 14a of the large capacity turbocharger is transferred to the exhaust gas passage of the small capacity turbocharger. 14b, increasing the exhaust gas flow rate in the exhaust gas passage 14b of the small capacity turbocharger and decreasing the exhaust gas flow rate in the exhaust gas passage 14a of the large capacity turbocharger. Therefore, the rotation speed of the small capacity turbocharger 2 increases,
The rotational speed of the large-capacity turbocharger 1 is reduced, and the boost pressures in both the air supply passages 7a and 11a are adjusted to be balanced.

Conversely, the boost pressure P ₁ in the air supply passage 7a of the large-capacity turbocharger 1 becomes smaller than the boost pressure P 2 in the air supply passage 11a of the small-capacity turbocharger ₂ , and ΔP'=
When a pressure difference of P ₂ - _{P 1} is generated, the diaphragm 13a of the actuator 13 is displaced based on the pressure difference ΔP', and the switching valve 12 is rotated in the direction B shown in the figure, thereby switching on the small capacity turbo supercharger. Exhaust gas passage 14b
A part of the exhaust gas is diverted to the exhaust gas passage 14a of the large capacity turbocharger, and the large capacity turbocharger 1
The rotation speed of the small-capacity turbocharger 2 is increased, and the rotation speed of the small-capacity turbocharger 2 is decreased.
It operates to balance the boost pressure of 1a.

In the above embodiment, the switching valve 12 was controlled by a mechanical actuator using a diaphragm 13a, but an electric actuator operated electrically based on a signal detected by a pressure detection sensor (not shown) is used. It goes without saying that the actuator may also be operated by an actuator (not shown).

Effects As a result of the above, the present invention provides air supply corresponding to all engine conditions such as starting, low speed high load region, medium speed high load region, high speed high load region, and partial load region to large and small capacity turbos. In addition to being made possible by switching the operation of the turbocharger, when large and small capacity turbochargers operate together at high speeds and high loads, the pressure of each boost pressure generated by the compressor of these turbochargers can be adjusted. A part of the exhaust gas in the exhaust gas passage of the turbo supercharger where the pressure difference is large is automatically adjusted and diverted to the exhaust gas passage of the turbo supercharger where the pressure difference is small. By providing a switching valve that balances each boost pressure from the compressor, it is possible to smoothly supply air to the engine, and moreover, the efficiency with which air is filled into the engine is improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional large- and small-capacity turbocharged engine. FIG. 2 is a characteristic diagram showing the relationship between load and rotation speed of large and small capacity turbocharged engines. Figure 3 shows the size of this invention.
FIG. 2 is a structural diagram of a small capacity turbocharger. 1, 1'... Large capacity turbocharger, 2, 2'...
Small capacity turbocharger, 3'...Engine, 4,
4', 8, 8'...Open/close switching valve, 5, 5', 9,
9'... Turbine, 6, 6', 10, 10'... Compressor, 7', 11'... Check valve, 7a, 11
a... Air supply passage, 12... Switching valve, 13... Actuator, 13a... Diaphragm, 14...
Exhaust gas, 14a, 14b...Exhaust gas passage, 1
5,16...Air supply.

Claims (1)

[Scope of utility model registration request] Large and small capacity turbochargers are arranged in parallel, and each turbocharger is switched on and off by the on-off switching valve. In engines equipped with large and small capacity turbochargers, which enable supply air to be matched to engine conditions such as load ranges, these turbo overcharges occur because the large and small capacity turbochargers operate together in high-speed, high-load ranges. The switching direction and opening area are controlled according to the pressure difference between the boost pressures of the charger's compressor, and the switching valve operates so that the boost pressures of the large and small capacity turbochargers are balanced. An engine with a turbo supercharger, characterized in that the turbocharger is attached to both exhaust gas passage partition walls on the turbine side from the on/off switching valve of the feeder.