GB2234290A

GB2234290A - Manifold turbocharger and waste-gate mounting arrangement

Info

Publication number: GB2234290A
Application number: GB9014423A
Authority: GB
Inventors: Carlo Ghiringhelli
Original assignee: Iveco Fiat SpA
Current assignee: Iveco SpA
Priority date: 1989-07-11
Filing date: 1990-06-28
Publication date: 1991-01-30
Also published as: SE9002353D0; GB9014423D0; SE9002353L; SE470108B; IT217139Z2; IT8953240V0

Abstract

A waste-gate valve 22, which is water cooled, is mounted on the water-cooled manifold 10 separately from the turbosupercharger 14, and is adapted to discharge the exhaust gases from the manifold when a predetermined supercharging pressure is reached. The waste-gate valve member (26, Fig. 2) co-operates with a seat (27) in the manifold exhaust passage (10a). <IMAGE>

Description

TITLE : "A supercharged diesel engine for boats, provided with a waste-gate valve." DESCRIPTION The present invention relates to a supercharged diesel engine, particularly for boats, including an exhaust manifold, a turbosupercharger mounted on the manifold, and a valve for discharging the exhaust gases in order to bypass the turbine of the turbosupercharger when a predetermined supply pressure is exceeded.

In supercharged diesel engines, the valve for discharging the exhaust gases, normally known as the waste-gate valve, is mounted on the turbosupercharger, in particular in correspondence with the turbine, and, as is known, is controlled by the pressure in the inlet duct downstream of the supercharger.

Moreover, in conventional solutions, the waste-gate valve includes a control portion constituted by a calibrated diaphragm which is acted on by the pressure supplied to the engine, and a rod which is connected to the diaphragm and is adapted to operate the obturator of the valve when the maximum supercharging pressure is reached.

As well as being somewhat complex from a mechanical point of view, this form of construction is adversely affected by the high temperatures reached in correspondence with the turbo supercharger due to conduction and radiation, and this reduces the reliability of the waste-gate valve. Atlhough this reduced reliability is permissible for motor-vehicle applications, it is not acceptable for marine applications in which mechanical damage to the engine can compromise the safety of the craft.

The object of the present invention is to provide an engine of the type specified at the beginning of the description which does not have the aforesaid disadvantages and which is very reliable.

According to the invention, this object is achieved by virtue of the fact that the exhaust valve is mounted on the exhaust manifold separately from the turbosupercharger.

By virtue of these characteristics, the waste-gate valve can be cooled effectively and, moreover, acts directly on an obturator whose seat is formed directly in the exhaust manifold, without the need for a transmission rod.

The exhaust manifold and the valve are preferably water-cooled.

Further advantages and characteristics of the diesel engine according to the invention will become clear from the detailed description which follows, provided purely by way of non-limiting example, with reference to the appended drawings, in which: Figure 1 is a perspective view of an exhaust manifold of an engine according to the invention, Figure 2 is a section taken on the line II-II of Figure 1, and Figure 3 is a section taken on the line III-III of Figure 2.

With reference to the drawings, an exhaust manifold for a supercharged diesel engine is generally indicated 10 and is adapted for installation in a pleasure craft with a planing hull. In such marine engines, a high "torque rise" and a quick response to transients are required because of the hydrodynamic characteristics of the planing hull which are different from those of conventional displacement craft.

The manifold 10 is water-cooled and therefore has a space 12 in which the cooling water circulates. A turbosupercharger 14 is mounted on the manifold and comprises a turbine 14a driven by the exhaust gases of the engine and a centrifugal compressor 14b with an associated air filter 16. The turbosupercharger 14 is mounted on the manifold 10 in correspondence with a flange 17 defining the duct for the passage of exhaust gases from the manifold to the turbine, from which they emerge in correspondence with the flanged aperture 18 of an exhaust pipe (not shown).

A waste-gate valve 22 is flange-mounted on the manifold 10 in a lateral region remote from the turbosupercharger 14 and, in known manner, has an operating capsule 22a connected to an inlet duct 24 of the engine by a pipe 23. The valve 22 also has an obturator 26 which acts in a seat 27 formed directly in an internal duct 10a of the manifold 10 so as to enable the pressure in the exhaust manifold 10 to be discharged through an exhaust opening 28 of the valve 22, on which an auxiliary exhaust pipe 31 (Figure 2) connected to the main exhaust pipe of the engine is flange-mounted at 30, when a predetermined pressure is exceeded in the intake duct 24.

In Figure 1, the cooling-water outlet pipe of the manifold 10 is indicated 32, whilst the cooling-water inlet and outlet pipes of the waste-gate valve 22 are indicated 33 and 34 respectively. The cooling-water inlet and outlet connectors of the valve body are indicated 33a and 34a, whilst the connector for connecting the capsule 22a to the pipe 23 which is in communication with the inlet duct 24 of the engine is indicated 23a.

It is clear from the above description that the waste-gate valve in the engine according to the invention always operates under conditions of safety and reduced radiation.

Claims

1. A supercharged diesel engine, particularly for boats, including an exhaust manifold (10), a turbosupercharger (14) mounted on the manifold (10), and a valve (22) for discharging the exhaust gases in order to bypass the turbine (14a) of the turbosupercharger (14) when a predetermined supply pressure is exceeded, characterised in that the exhaust valve (22) is mounted on the exhaust manifold (10) separately from the turbosupercharger (14).

2. An engine according to Claim 1, characterised in that the exhaust manifold (20) and the valve (22) are water-cooled.

3. An engine according to Claim 1 or Claim 2, characterised in that the valve seat (27) is formed directly in the exhaust manifold (10a, 10).

4. A supercharged diesel engine substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.