GB2377253A

GB2377253A - Cooling system including a pump with a flow restriction valve

Info

Publication number: GB2377253A
Application number: GB0212842A
Authority: GB
Inventors: Ian Graham Pegg; Leslie William Routledge; Richard Durnford
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2001-07-05
Filing date: 2002-06-05
Publication date: 2003-01-08
Also published as: EP1404950B1; GB0212842D0; EP1404950A1; WO2003004840A1; DE60202073T2; GB0116433D0; DE60202073D1

Abstract

A cooling system for an engine includes a pump 12 which comprises an inlet 15, an outlet 16 and a flow restriction valve 23. The valve 23 may be operated to restrict the output of the pump 12 by a vacuum controlled actuator (24 figure 2) which, in turn, is operated by a valve control (34 figure 3) acting on signals from a control module (35 figure 3). The control module 35 may receive input signals from a number of different sources, including a valve condition sensor (25 figures 2,3). The pump 12 may include an impeller with a pulley wheel 22 which is driven by a crankshaft of an engine via a belt 13.

Description

Cooling System for a Motor Vehicle Engine Field This invention relates to cooling systems for internal combustion engines, particularly for motor vehicles.

Background of the Invention A typical automobile engine cooling system includes an engine coolant jacket, a radiator, a fan for drawing air through the radiator, a circulatory pump for circulating the coolant from the engine through the radiator and return.

Such a system typically includes a thermostat which opens to allow the circulation of the coolant when the engine reaches a minimum desired operating temperature. The coolant flow is driven conventionally by a pump rotated by a belt driven by the crankshaft pulley and the flow rate is dependant upon engine speed.

In order to improve engine efficiency different means have been utilised to enable the engine to operate at as higher temperature as is possible. For example in US 4 744 335, the engine is provided with a servo controlled flow valve at its coolant outlet. US Patent 5 975 031 discloses a cooling system having a pump with an electrically driven motor the speed of which is varied with engine temperature. The system in US 5 975 031 also includes a

radiator by-pass duct and discloses the use of a control valve upstream of the pump to control the ratio of the flows of water entering the pump from both the by-pass duct and radiator. US Patent 6 032 618 discloses a cooling system in which a control valve located upstream of the pump controls the flow of water through the system dependant upon signals received from an electronic control.

The present invention provides a means of controlling the engine cooling system which is suitable for engine driven coolant pumps.

Statements of Invention According to the present invention there is provided an internal combustion engine coolant pump having an inlet for receiving coolant from a radiator or other coolant circuit and an outlet directing coolant to the engine, the outlet having a flow restricting valve therein operable to vary the output from the pump.

The flow restricting valve in the outlet of the pump creates a restriction at the outlet which has advantages in that cavitation at the inlet is not made worse and any increase in pressure due to the restriction is seen only in the pump and not in the rest of the coolant system.

Increasing the flow restriction at the outlet of an impellor type pump reduces its power consumption giving a

direct reduction in fuel consumption.

The pump control valve is provided with an actuator, preferably a vacuum operated actuator which operates from a vacuum source on the vehicle, e. g. a vacuum pump or through the vehicle inlet manifold pressure, for operation of the valve. The pump control valve is also provided with a sensor which monitors the control position of the valve.

The pump could be an electrically driven impeller pump, but is preferably a mechanically driven impeller pump having a pulley wheel fixed to the pump shaft and driven by a suitable means e. g. endless belt, chain etc., connected to a pulley wheel fixed to the engine crankshaft. The system drive losses as compared with an electrically driven pump are lower. With a typical electrically driven pump the vehicle alternator must be upgraded and system losses are such the power consumed to drive the coolant pump is about 120% higher than for the engine driven pump.

The invention also relates to engine cooling systems that include the above type of pump.

Yet another aspect of the invention relates to a motor vehicle internal combustion engine cooling system having a liquid coolant pump having an inlet for receiving coolant

from a radiator and outlet passing coolant to the engine, and a flow restricting valve operable to vary the volume output from the pump.

The pump may be a separate unit mounted on the engine or a pump which is incorporated with its impeller located in the engine coolant jacket.

The system may further includes a control module for operation of the restricting valve, the module being connected to a plurality of sensors for monitoring a plurality of engine conditions, and preferably vehicle passenger compartment conditions.

Yet another aspect of the invention provides a method of controlling the flow of cooling fluid through the cooling system of an internal combustion engine, the system includes a circulatory pump, wherein the pump output is controlled by a flow restricting valve located at the pump outlet.

The restricting valve may be located in the pump outlet or adjacent thereto.

Description of the Drawings The invention will be described by way of example only and with reference to the accompanying drawings in which: Fig. 1 is a schematic drawing of an vehicle engine

with an external coolant pump, Fig. 2 is a schematic drawing of a coolant pump according to the present invention, and Fig. 3 is a flow diagram of a control for the restricting valve in the pump of Fig. 2 Detailed Description of the Invention With reference to FIG 1, there is shown an internal combustion engine 11 having a cooling jacket through which a liquid coolant, typically a water/glycol mix, is pumped.

The coolant is pumped through the engine 11 by a pump 12 mounted externally of the engine and which is rotated by an endless belt 13 driven by a pulley 14 conventionally secured to the engine crankshaft. The coolant enters the pump inlet 15 from a radiator (see Fig. 3) and is pumped through pump outlet 16 into the engine 11 via conduit 17.

The coolant exits the engine via a thermostatically regulated control valve or valves 18.

With reference also to Fig. 2, the pump 12 is an impeller pump and the impeller shaft 21 is rotated by a pulley wheel 22 (see Fig. 1) driven by the belt 13 in a well known manner. The coolant flow from the pump passes through a volume flow regulating or restricting valve 23 which may be of any suitable type, for example a ball valve, or plate valve, which causes minimum flow restriction when fully open.

The valve 23 may be enclosed in a separate housing which is mounted to the pump outlet 16 to form a single assembly, but preferably the valve is housed within the pump outlet 16 forming a single unit.

The valve 23 is operated by an actuator 24 which again may be of any suitable type, for example hydraulic, electrical, or preferably a vacuum actuator which operate by a vacuum source on the vehicle. The actuator 24 is biased to a valve open condition so that the valve 23 restricts coolant flow only when the actuator is energised, and is open in the case of actuator failure.

The valve condition is monitored by a sensor 25.

Now with reference to Fig. 3 there is shown a cooling system which includes the pump 12. The liquid coolant is pumped into the engine 11 and the heated coolant exits the engine through outlet 18 and passes to a radiator 31 and typically to a heat exchanger 32 for heating the vehicle passenger compartment. The coolant then returns to the engine 11 via the pump 12.

A cooling fan 33 is arranged to draw cooling air through the radiator 31.

The valve actuator 24 is operated by a valve control 34 which receives control signals from a cooling system control module 35. The control module 35 receives input signals from a plurality of different sources. The module

35 receives a valve condition signal from sensor 25 to complete the control loop for the restricting valve 23, but the actual valve condition will be determined in response to other engine condition signals and to parameters which my be programmed into an engine map.

The sensors may be divided into three types, vehicle parameter 36, power train parameters 37, and heating and cooling parameters 38.

The vehicle parameter sensors 36 may include torque demand sensor e. g. accelerator pedal position, gear, speed and ignition key status.

The power train sensors 37 may include sensors for engine air intake temperature, cylinder head metal body temperature, engine coolant outlet temperature, engine speed, engine air flow, and engine fuel demand.

The heating and cooling sensors may include ambient air temperature, ambient pressure, air conditioning, passenger compartment temperature settings and fan control settings, and radiator fan status.

The above lists of sensors are by way of example only The control module 35 processes the input signals from the various sensors and determined the optimum engine

temperature in accordance with the pre-programmed engine map. The valve actuator 24 is then activated to increase or decrease the flow through the valve 23 dependant upon the relationship between the required engine metal temperature and actual engine metal temperature and/or coolant flow rate required.

Claims

1. An internal combustion engine coolant pump having an inlet for receiving coolant from the cooling circuit and an outlet directing coolant to the engine, characterised by the outlet having a flow restricting valve therein operable to vary the output from the pump.

2. A pump as claimed in Claim 1 further including an actuator to operate the valve.

3. A pump as claimed in Claim 2 wherein the actuator is a vacuum operable actuator.

4. A pump as claimed in Claim any one of Claims 1 to 3 and further including a sensor for sensing the restricted condition of the valve.

5. A pump as claimed in any one of Claims 1 to 4 wherein the pump is an impeller pump.

6. A pump as claimed in Claim 5 wherein the impeller pump is driven by mechanical means.

7. A pump as claimed in Claim 6 having an impeller shaft with a pulley wheel thereon which in use is driven by drive means connected to the vehicle engine crankshaft.

8. A motor vehicle internal combustion engine cooling

system including a pump as claimed in any one of Claims 1 to 7.

9. A motor vehicle internal combustion engine cooling system having a liquid coolant pump with an inlet for receiving coolant from a radiator and an outlet directing coolant to the engine, the system further comprising a flow restricting valve operable to vary the output from the pump.

10. A system as claimed in Claim 8 or Claim 9 wherein the system further includes a control module for operation of the restricting valve, the module being connected to an actuator for operation of the valve, a valve position sensor and plurality of others sensors for monitoring a plurality of engine and vehicle conditions.

11. A method of controlling the flow of cooling fluid through the cooling system of an internal combustion engine which includes a circulatory pump, wherein the volume output of the pump is controlled by a flow restricting valve located at the pump outlet.

12. The method as claimed in Claim 11, wherein the restricting valve is operated by a control module which is responsive to signals received from a valve condition sensor and a plurality of other sensors which monitor a plurality of engine operating conditions.

13. An internal combustion engine coolant pump substantially as described herein with reference to the accompanying drawings.

14. A motor vehicle internal combustion engine cooling system substantially as described herein with reference to the accompanying drawings.

15. A method of controlling the flow of cooling fluid through the cooling system of an internal combustion engine and substantially as described herein with reference to the accompanying drawings.