Method for operating a coolant circuit

Patent metadata

Field	Value
Publication number	US-10161361-B2
Application number	US-201313733076-A
Country	US
Kind code	B2
Filing date	Jan 2, 2013
Priority date	Jan 2, 2012
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A method for operating a liquid coolant circuit of an internal combustion engine is described in which the coolant circuit contains an integrated EGR cooler such that the cooling system has a single circuit with two operational modes. The method includes a controller that can switch between operational modes to enable delivery of coolant to the EGR cooler when the flow of coolant through the block cooling circuit is blocked. In the second operational mode, the method also includes using an auxiliary pump to pass coolant to the EGR cooler while bypassing the main coolant pump, which can occur by adjusting the flow of coolant through the circuit so the flow through a bypass line is reversed relative to the inherent forward direction of flow in the bypass line during the first operational mode.

First claim

The invention claimed is:

1. A method for operating a coolant circuit of an internal combustion engine, in which the coolant circuit includes:
at least one main coolant pump located upstream of an engine block,
at least one block cooling circuit,
a coolant thermostat in direct connection with a valve arranged at an outlet of the block cooling circuit via a bypass line, and
at least one EGR cooler, the EGR cooler connected at least to a heat exchanger circuit and further connected to the valve at the outlet of the block cooling circuit via a connecting line,
the method comprising:
determining whether a flow of coolant through the block cooling circuit is to be stopped based on a temperature within the block cooling circuit;
operating the engine with the flow of coolant through the block cooling circuit, and adjusting the valve at the outlet of the block cooling circuit to pass coolant in a forward direction from the outlet of the block cooling circuit to the coolant thermostat; and
operating the internal combustion engine with the flow of coolant through the block cooling circuit stopped, flowing the coolant through the EGR cooler, switching a control valve to stop the flow of coolant in the block cooling circuit, activating an auxiliary coolant pump, and adjusting the valve at the outlet of the block cooling circuit to pass coolant in a reverse direction from the coolant thermostat to the valve at the outlet of the block cooling circuit and then to the EGR cooler via the bypass line and the connecting line, while bypassing the main coolant pump and the engine block.

2. The method of claim 1 , further comprising stopping the flow of coolant through the block cooling circuit during a warm-up phase of the engine following an engine cold start.

3. The method of claim 1 , further comprising adjusting the valve at the outlet of the block cooling circuit to also pass coolant from the outlet of the block cooling circuit to the EGR cooler via the connecting line when operating the engine with the flow of coolant through the block cooling circuit.

4. The method of claim 1 , wherein the coolant circuit further includes a valve arranged between the main coolant pump and the coolant thermostat, the valve further coupled to the heat exchanger circuit, the method further comprising switching a position of the valve arranged between the main coolant pump and the coolant thermostat to pass coolant from the heat exchanger circuit to the bypass line and then through the bypass line in the reverse direction in response to activating the auxiliary coolant pump.

5. The method of claim 4 , wherein the main coolant pump is shut-down when reversed flow of coolant through the bypass line bypasses said main coolant pump.

6. The method of claim 1 , wherein a heat exchanger in the heat exchanger circuit operates as a vehicle passenger compartment heater.

7. The method of claim 1 , wherein the internal combustion engine includes a split cooling system.

8. A method for operating an engine liquid-coolant circuit, comprising:
operating an engine in a first mode,
operating the engine in a second mode,
during the first mode where coolant flows through an engine block, flowing coolant through a bypass line in a forward direction from a valve downstream of the engine block to a coolant thermostat upstream of a main coolant pump,
during the second mode where coolant flow through the engine block is blocked, flowing coolant through the bypass line in a reverse direction from the coolant thermostat to the valve and then to a heat exchanger; and
switching to the second mode from the first mode by sending signals, with a controller of the engine, to actuators of each of a control valve arranged between the main coolant pump and an inlet of the engine block, a valve arranged between the coolant thermostat and the main coolant pump, the coolant thermostat, and the valve downstream of the engine block to change positions of each of the control valve, the valve arranged between the coolant thermostat and the main coolant pump, the coolant thermostat, and the valve downstream of the engine block, and further comprising blocking the coolant flow through the engine block by switching the control valve,
wherein the second mode includes circulating coolant in the reverse direction through a second circuit that bypasses the engine block via an auxiliary pump, and
wherein the main coolant pump is deactivated during the second mode.

9. The method of claim 8 , wherein the heat exchanger is an EGR cooler.

10. The method of claim 8 , wherein a control system selects from among the first and second modes based on an engine cold start and warm-up condition.

11. The method of claim 8 , wherein the heat exchanger is a heater core of a passenger compartment heating system, the method further comprising blowing passenger compartment heating air through the heater core.

12. A method for operating an engine liquid-coolant circuit, comprising:
operating an engine in a first mode,
operating the engine in a second mode,
during the first mode, flowing coolant through a bypass line in a first flow direction from an outlet of an engine block to a coolant thermostat upstream of a first pump via operation of the first pump, and
during the second mode, flowing coolant through the bypass line in a reverse direction from the coolant thermostat upstream of the first pump to the outlet of the engine block while bypassing the first pump and the engine block and then to a heat exchanger via operation of a second pump,
wherein the method further comprises:
during the first mode, with a controller of the engine, sending a signal to an actuator of a valve arranged downstream of the engine block to adjust the valve arranged downstream of the engine block to flow coolant to a radiator and then from the radiator to the coolant thermostat, and
during the second mode, with the controller, sending a signal to the actuator of the valve arranged downstream of the engine block to adjust the valve arranged downstream of the engine block to disable coolant flow from the valve downstream of the engine block to the radiator.

13. The method of claim 12 , wherein the heat exchanger is a heater core of a passenger compartment heating system.

14. The method of claim 12 , wherein the heat exchanger is an EGR cooler.

15. The method of claim 12 , further comprising:
during the second mode, flowing coolant from an outlet of a circuit containing the heat exchanger to the coolant thermostat.

16. The method of claim 1 , wherein the engine further comprises a controller, wherein adjusting the valve at the outlet of the block cooling circuit comprises the controller sending a signal to an actuator of the valve at the outlet of the block cooling circuit to adjust the valve at the outlet of the block cooling circuit, and wherein switching the control valve comprises the controller sending a signal to an actuator of the control valve to switch the control valve.

Assignees

• Ford Global Tech Llc

Inventors

• Quix Hans Guenter
• Lach Rainer
• Mehring Jan

Classifications

• F02M26/33 Primary

  controlling the temperature of the recirculated gases · CPC title

• F02M26/28

  with liquid-cooled heat exchangers · CPC title

• F02M25/0738 Primary

  Mechanical Engineering · mapped topic