GB2201504A

GB2201504A - Fuel cooler

Info

Publication number: GB2201504A
Application number: GB08729420A
Authority: GB
Inventors: Dipl-Ing Heinz Richter; Dr Ing Manfred Hage; Dipl-Ing Karl Noll; Dipl-Ing Peter Kropp
Original assignee: Wieland Werke AG
Current assignee: Wieland Werke AG
Priority date: 1986-12-20
Filing date: 1987-12-17
Publication date: 1988-09-01
Also published as: FR2608683B3; IT8768096A0; GB8729420D0; IT219109Z2; DE3643782A1; DE3643782C2; FR2608683A1; IT8753905V0

Abstract

A fuel cooler comprises an inner tube (1) and a jacket tube (2) arranged concentrically therewith. The inner tube (1) has helical ribs on its inner surface and helically encircling outer ribs (1'). The inlet orifice (4) and outlet orifice (6) for the fuel are arranged at opposite ends of the cooler. A coolant flows axially through the inner tube (1), whilst the fuel is conveyed, via the inlet orifice (4) and the outlet orifice (6), through the annular space (3) between the inner tube (1) and jacket tube (2). <IMAGE>

Description

FUEL COOLER This invention relates to a fuel cooler, particularly although not exclusively, to a petrol fuel cooler.

Such fuel coolers are mainly used in injection engines, in which cooling is intended to prevent the adverse formation of bubbles in the fuel. In the fuel cooler, the excess heat is transmitted to the gaseous refrigerant of the air-conditioning system, as a result of which the refrigerant is further heated.

In a known fuel cooler., for example according to German Patent Specification 3,117,661, comprising an inner tube and a circumferentially encompassing jacket tube, a so-called turbulence plate has to be inserted separately into the annular space between the inner tube and the jacket tube. The provision of such a plate involves a high cost outlay and is time-consuming.

The object of this invention is to provide a simplified fuel cooler in which a way that, whilst the turbulence effects are at least the same as the above prior art, there is no need for the separate insertion of a turbulence generator.

According to this invention there is provided fuel cooler comprising an inner tube and an outer jacket tube, both said tubes being rectilinear along a common longitudinal axis and concentric with one another, said inner tube being internally ribbed for ensuring turbulent flow of coolant therethrough and externally provided with helically circumferentially surrounding fins, there being an annular space between the radially outer ends of said fins and the inner surface of said outer jacket tube, said annular space being closed at opposing ends thereof, and an inlet port and an outlet port at opposing ends of the outer jacket tube for passage of fuel, whereby fuel is admitted to the annular space through the inlet port, cooled by coolant flowing axially through the inner tube and withdrawn from the outlet port.

Preferably there is at least one internal rib which is helically formed and has the same pitch angle as the outer fins. Alternatively there is at least one internal rib which is helically formed and has a pitch angle which is different from the pitch angle of the outer fin.

Preferably the fin height h of the outer fins is in the range 0.3 to 2.0mm.

In one embodiment the internal rib is interrupted in the direction of the helix. Preferably the depth w of the internal rib is in the range 0.03 to 0.45mm.

In the embodiment where there is provided an internal rib which is helically formed and which has a pitch angle that is different from the pitch angle of the outer fin, preferably the rib height of the internal rib is in the range 0.1 to 0.8mm.

Advantageously the inlet port and outlet port are arranged in the circumference of the jacket tube.

In one embodiment at least one connection member is arranged at a distance from the inlet port and the outlet port respectively and is conductively connected to the latter.

In another embodiment advantageously the connection member for the outlet port is adjacent to the connection member for the inlet port, the outlet port connection member being connected to the outlet port by a pipe-line extending along the jacket tube. In such another embodiment conveniently a second annular space closed at opposing ends thereof is provided between the jacket tube and a concentric outer tube, the outlet port being formed by holes distributed over the circumference of the jacket tube, and a connection member for the second annular space is provided adjacent to the connection member for the inlet port.

Advantageously the the connection member for the inlet port passes through the second annular space and is sealed therefrom.

In one embodiment the outer tube is shorter than the inner tube and jacket tube, and the connection member for the inlet orifice is arranged directly on the jacket tube.

Conveniently the connection members are circumferentially offset from one another.

The invention will now be described with reference to the following exemplary embodiments. In the drawings: Figures 1-4 each show a longitudinal cross-section through a side view of different embodiments of a full cooler in accordance with the invention, Figure 5 shows a cross-section along the line A-A in Figure 3, and Figure 6 explains the notation used for the ribbed tube.

The fuel cooler shown in Figure 1 has an inner tube 1 and a smooth jacket tube 2, both tubes being rectilinear along a common longitudinal axis and being concentric. The inner tube 1 is designed as a ribbed tube with helically encircling outer fins or ribs 1' and also has a helical inner rib or corrugation. The outer ribs 1' and the inner corrugation extend circumferentially round the inner tube at the same pitch angle (not shown in detail).

An annular space 3 is formed between the tubes 1, 2 which is closed at its end faces. The jacket tube 2 has an inlet orifice 4 with an associated connection piece 5 and an outlet orifice 6 with an associated connection piece 7. The orifices 4 and 6 are arranged in opposing end regions of the cooler. The tube 2 has opposing end terminals 11 for connection to other pipes (not shown).

When the cooler is in operation, the fuel to be cooled, especially petrol, flows through the annular space 3 from the inlet orifice 4 to the outlet orifice 6. Coolant is circulated in the inner tube 1 in parallel flow or in counter flow. The ribbed tube 1 having an inner corrugation, whilst being simple to handle in mechanical tems, ensures good turbulence formation and therefore good heat transmission both in the coolant and in the fuel.

The embodiments of the fuel cooler shown in Figures 2 and 5 are suitable for when the connection pieces 5, 7 are to be arranged close to one another. Consequently, in order to return the fuel, as shown in Figure 2, the connection piece 7 is connected to the outlet orifice 6 by a pipeline 8 extending along the jacket tube 2. In figures 3 and 4, for returning the fuel, an additional annular space 9 closed at its end faces is provided between the jacket tube 2 and an outer tube 10. Here, the outlet orifice for the fuel in the jacket tube 2 is formed by several holes 6' provided in the circumference of the jacket tube 2. In Figure 3, the connection piece 5 for the inlet orifice 4 passes through the second annular space 9 and is sealed therefrom. To avoid such a passage, in the Figure 4 embodiment, the outer tube 10 is shorter than the inner tube 1 and the jacket tube 2, so that the connection piece 5 can be soldered directly to the jacket tube 2.

In Figures 1 to 3, terminals 11 are pushed onto the inner tube 1, whilst in the alternative version of Figure 4 they are inserted into the jacket tube 2 and soldered to the widened end of the inner tube 1.

Figure 5 shows, in particular, the circumferential offset arrangement of the connection pieces 5, 7.

Referring now to Figure 6, a fuel cooler as shown in the embodiment of Figures 4 and 5 was produced from tubes having the following dimensions:

Table: Length Outside Diameter Wall (mm) (mm) Thickness (mm) Inner tube 147 (ribbed tube) (total length non-ribbed end d1 = 16 SI = 1 ribbed part 132 d5 = 13 s2 = 0.8 (core wall thickness) Jacket tube 164 - 18 1 Outer tube 124 28.4 1.'2 Ribbed tube: rib height h of the outer ribs: 0.7mm; rib spacing m (rib centre distance): 2.2mm; corrugation depth w of the inner corrugation: 0.3 - 0.4mm; Diame-ter of the inlet orifice: 8mm; Diameter of the four outlet orifices: 6mm.

When the petrol cooler described was used with R 12 as coolant, good results were achieved.

Claims

CLAIMS:

1. Fuel cooler comprising an inner tube and an outer jacket tube, both said tubes being rectilinear along a common longitudinal axis and concentric with one another, said inner tube being internally ribbed for ensuring turbulent flow of coolant therethrough and externally provided with helically circumferentially surrounding fins, there being an annular space between the radially outer ends of said fins and the inner surface of said outer jacket tube, said annular space being closed at opposing ends thereof, and an inlet port and an outlet port at opposing ends of the outer jacket tube for passage of fuel, whereby fuel is admitted to the annular space through the inlet port, cooled by coolant flowing axially through the inner tube and withdrawn from the outlet port.

2. Fuel cooler according to claim 1 wherein there is at least one internal rib which is helically formed and has the same pitch angle as the outer fins.

3. Fuel cooler according to claim 1 wherein there is at least one internal rib which is helically formed and has a pitch angle which is different from the pitch angle of the outer fin.

4. Fuel cooler according to any preceding claim wherein the fin height h of the outer fins is in the range 0.3 to 2.0mm.

5. Fuel cooler according to any preceding claim wherein the internal rib is interrupted in the direction of the helix.

6. Fuel cooler according to any preceding claim wherein the depth w of the internal rib is in the range 0.03 to 0.45mm.

7. Fuel cooler according to claim 3, wherein the rib height of the internal rib is in the range 0.1 to 0.8mm.

8. Fuel cooler according to any preceding claim wherein the inlet port and outlet port are arranged in the circumference of the jacket tube.

9. Fuel cooler according to any preceding claim wherein at least one connection member is arranged at a distance from the inlet port and the outlet port respectively and is conductively connected to the latter.

10. Fuel cooler according to claim 9 wherein the connection member for the outlet port is adjacent to the connection member for the inlet port, the outlet port connection member being connected to the outlet port by a pipe-line extending along the jacket tube.

11. Fuel cooler according to claim 9 wherein a second annular space closed at opposing ends thereof is provided between the jacket tube and a concentric outer tube, the outlet port being formed by holes distributed over the circumference of the jacket tube, and a connection member for the second annular space is provided adjacent to the connection member for the inlet port.

12. Fuel cooler according to claim 11 wherein the connection member for the inlet port passes through the second annular space and is sealed therefrom.

13. Fuel cooler according to claim 11 wherein the outer tube is shorter than the inner tube and jacket tube, and the connection member for the inlet orifice is arranged directly on the jacket tube.

14. Fuel cooler according to any of claims 9 to 13 wherein the connection members are circumferentially offset from one another.

15. Fuel cooler substantially as herein described with reference to, and as shown in, Figure 1 or 2 or 3, 5 or 4 and 6 of the accompanying drawings.