NZ504454A - Internal combustion engine radiator with coolant impeller within radiator header tank - Google Patents

Abstract

A coolant pump 22 for an IC engine cooling system is mounted in the radiator header tank 10. The pump is powered by electric motor 12. The pump drive shaft is aligned with the longitudinal axis of the header tank.

Description

NEW ZEALAND PATENTS ACT, 1953 No- Divided out of NZ 332759 Date: Dated 11 November 1998 COMPLETE SPECIFICATION IMPROVEMENTS RELATING TO THE LIQUID COOLED I C. ENGINES We, CONCENTRIC PUMPS LIMITED, a British company, of Gravelly Park, Tyburn Road, Erdington, Birmingham B24 8HW, United Kingdom, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: (followed by page -la-) INTELLECTUAL PROPERTY OFFICE OF NZ NAY 2CC3 RECEIVED la IMPROVEMENTS RELATING TO THE LIQUID COOLED I.C. ENGINES Claims to the invention can be found in the present specification, and in Parent New Zealand Specification No. 332759, from which the present specification has been divided.

This invention relates to liquid cooled internal combustion or I.C. engines. It is conventional to provide a coolant circuit including a radiator allowing heat exchange between the coolant and for example a fan driven flow of ambient air. The coolant is driven from engine to radiator and vice versa via flexible hoses which allow for relative movement of the engine and radiator, by a so-called water pump having an impeller mounted on a drive shaft also carrying a pulley. The impeller is located in a chamber m the engine, on the face of the cylinder block adjacent the radiator, and the pulley is engaged by a vee belt driven from the crankshaft and often also serving to drive an alternator and the fan, in the latter case possibly via an electric clutch allowing the fan to turn or not according to control applied by an engine management system or in simpler versions under the control of a thermostat sensing coolant temperature.

The impeller, drive shaft and a plate closing the impeller chamber and containing bearing and seal form a single unit which is replaceable. The usual reasons for replacement are leakage caused by chemicals, dirt or impurities in the coolant, or wear caused either by long use, or quite frequently by improper use such as over tightening the drive belt which places undue load on the bearing or seal.

An object of this invention is to provide improvements over the prior art.

As claimed herein, according to one aspect of the invention there is provided a liquid cooled I.C. engine cooling system comprising a radiator assembly having a radiator and an impeller within the interior of the radiator mounted on a drive shaft, the axis of the drive shaft being substantially aligned with the length of the radiator.

Hence, a compartment in the radiator header tank, assuming a vertical flow radiator in this instance, may be used as an impeller chamber, and the chamber may be closed by a plate carrying a bearing and a seal for co-operation with the drive shaft.

Preferably, the drive shaft carries a separate and distinct drive motor, which will usually be an electric motor. The motor may be under the control of an engine management system or a thermostat and this gives a completely new control m engine management. Hitherto, as far as the applicants are aware, it has only been the coolant fan which has been controlled in this way. The significance of controlling the water pump by the same or a similar system is that power utilization in driving the pump is avoided at times when the pump is unnecessary, that is when the coolant temperature has not risen to a point where heat exchange is required, and moreover rise in engine temperature to the required range can be more rapidly controlled. These factors can lead to substantially improved fuel consumption as compared to what is possible with known designs. Additionally, the system can continue to cool an engine even after the ignition has been turned off - for example to ensure a predetermined non-operating temperature is reached.

Independence of drive from engine speed also allows water pump operating speed to be selected in terms of efficiency. For example, when an engine is idling and a vehicle is stationary in traffic, it may be desirable for the pump to operate at maximum speed (assuming that speed variation is a possibility with the chosen design) whereas when the vehicle is travelling lower pump speeds will be possible. This in general is a reverse of what is provided by the conventional arrangements.

Again, whilst the foregoing description is solely in relation to engine cooling, the same possibilities exist where the coolant is used for other purposes for example as part of the heating system of a vehicle. In such instances it may be that operation of the impeller or an impeller to drive engine coolant via the heating system is required at times when engine cooling is not required, and the invention contemplates the use of multiple impellers and/or valving arrangements allowing diversion of the coolant according to requirements for the different purposes. Multiple impellers can be used in parallel (effectively multiple pumps) or in series thereby effectively to provide a multiple stage pump. Accordingly, for a parallel arrangement or suitable valve arrangement, coolant flow to the radiator can be restricted or eliminated and flow can be directed to other components of a vehicle or engine.

Another possibility with the use of an electric motor is to make a magnetic coupling between the impeller and the motor so that the plate carrying the shaft bearing can be completely closed and again eliminate risk of leakage to the exterior. In the event of motor failure, the motor can be replaced without affecting the integrity of the coolant system.

However, in a development of magnetic coupling, the drive motor may be replaced by a pulley engaged with a drive belt so that the impeller is belt driven for example from the engine crankshaft with a magnetic coupling to the impeller and although this is not as readily susceptible of control, it may be considered to have advantages as compared to the conventional arrangements and location of the impeller and water pump. A preferred embodiment encompasses this possibility and also that of using a conventional belt drive without even a magnetic coupling, as long as the radiator location of the impeller is employed.

The header tank may have pump components included as part of unitary injection moulded or die-cast structure and additional components assembled thereto.

Instead of providing the impeller chamber in the header tank or like part of the radiator, it may be located in a chamber housing connected to the radiator in this case the chamber may also form part of a complete unit which is replaceable in case of need.

Described herein, and claimed in parent New Zealand Specfication No. 332759, is a liquid cooled internal combustion engine cooling system comprising a radiator assembly having a radiator with a flange, and a pump having an impeller mounted on a drive shaft, the pump having a corresponding flange rigidly connected to said radiator flange by bolts such that the pump is supported entirely by the said flange connection.

The invention is more particularly described with reference to the accompanying drawings in which:- FIGURE 1 is a diagrammatic cut-away view showing an end portion of a radiator header tank provided with the invention; FIGURE 2 is a diagrammatic perspective view of a different embodiment; FIGURE 3 is an exploded view showing the components used in the Figure 2 construction; FIGURE 4 is a side elevation of the arrangement shown in Figure 1; FIGURE 5 is an underneath plan view of the same; FIGURE 6 is a section taken on the line VI-VI of Figure 4; and FIGURE 7 is a block diagram of a system according to the invention. Claims to the embodiment having a pump connected to and supported by a radiator flange can be found Parent New Zealand Specification No. 332759.

Turning first to Figures 1 and 4 to 7, the embodiment illustrated therein has the water pump located in one end of the header tank 10 of a vehicle radiator associated with an I.C. engine. An electric drive motor 12 is mounted on one end face of the header tank with a suitable interposed seal and bearings provided either in the header tank itself or in the drive motor construction. Coolant is drawn in through the inlet 14 located axially and indeed co-axial with the drive motor, and expelled through the outlet 16 which in this instance is of somewhat of a "figure of 8" cross-section, thereby providing a pair of passages. This coolant flow is caused by impeller 18 mounted on drive shaft 20 and housed in an appropriate volute 22.

Figure 7 shows a schematic block diagram of a cooling system according to the invention where it can be seen that motor 12 communicates with a controller 32 such as an engine management system, which controller further comprises a thermo couple 34 for monitoring the engine temperature. Of course, multiple thermo couples can be used for monitor temperature at different locations. Accordingly, controller 32 is used to actuate drive motor 12 thereby to effect pumping by impeller 18 as appropriate and/or as predetermined dependent on the engine speed and/or temperature.

Turning next to Figures 2 and 3 wherein like reference numerals are used as to those used in Figures 1 and 4-6, for like parts, the motor shaft 20 here extends normal to the length of the header tank 10. The motor 12 is associated with a cover 24 which provides a seal to the shaft 20, and the cover closes pump housing 26 which forms an equivalent to the volute in the Figure 1 construction. The impeller chamber is formed in the pump housing and the impeller 18 lies in that chamber which is closed by the cover 24.

The pump housing includes flange 28 which is bolted face to face against a like flange 30 on the header tank.

It will be appreciated that any seal required by an electric motor is much simpler than one required where a shaft is required to project to a drive pulley: essentially with the electric motor there will be no rotating part projecting to the exterior and the motor can be completely "canned".

Whilst the specific embodiments described use centrifugal flow impellers, this is not essential and axial flow or mixed flow arrangements are possible and may be advantageous where space considerations are critical.

Further, whilst the invention has been specifically described in relation to location of the impeller in the radiator header tank, different locations can be provided around the radiator to suit particular requirements particularly in terms of space considerations.

Claims (16)

WHAT WE CLAIM IS:

1. A liquid cooled internal combustion engine cooling system comprising a radiator assembly having a radiator and an impeller within the interior of the radiator mounted on a drive shaft, the axis of the drive shaft being substantially aligned with the length of the radiator.

2. A system according to Claim 1 wherein the radiator comprises a header tank which is adapted to form a chamber for the impeller.

3. A system according to Claim 2 wherein the chamber is closed by a plate carrying a bearing and a seal for co-operation with the drive shaft.

4. A system according to any preceding claim comprising a controller for controlling the operation of the impeller in response to predetermined engine temperature characteristics.

5. A system according to Claim 4 wherein the controller comprises part of an engine management system for a vehicle.

6. A system according to Claim 4 or 5 wherein the controller comprises a thermostat which monitors the engine temperature of a vehicle.

7. A system according to Claim 4, 5 or 6 wherein the controller enables an engine to reach a desired operating temperature before commencing cooling of the engine.

8. A system according to Claim 4, 5, 6 or 7 wherein the controller enables continued operation of the impeller after an engine ignition has been turned off, thereby to ensure continued cooling of an engine.

9. A system according to any one of Claims 1 to 8 wherein the impeller is magnetically coupled to an electric motor through a relatively stationary and relatively non-magnetic plate. 8

10. A system according to any one of Claims 1 to 9 comprising two or more impellers, allowing diversion of the coolant so that it does not necessarily pass through the radiator.

11. A system according to Claim 10 wherein the two or more impellers are in parallel.

12. A system according to Claim 10 wherein the two or more impellers are independent of one another.

13. A system according to Claim 10 wherein the two or more impellers are in series with one another thereby to provide a multiple stage pump.

14. A system according to any one of Claims 1 to 13 comprising a valving arrangement, allowing diversion of the coolant so that it does not necessarily pass through the radiator.

15. A liquid cooled internal combustion engine cooling system, substantially as hereinbefore described with reference to Figure 1, 4, 5, 6, or 7 of the accompanying drawings.

16. A system according to any one of Claims 2 to 15 wherein the header tank is formed by injection moulding or diecasting to provide a volute or housing for the impeller. G^f^53rA^9:...?s:?.vyr^S> I—» By thd authorised agents A J HAriK Per