Coolant circuit for an internal combustion engine and method of operating a coolant circuit

Abstract

The invention relates to a coolant circuit (1) for an internal combustion engine (2), wherein the coolant can circulate between the internal combustion engine (2) and a heat sink (3) depending upon a switchable valve (4), which is closed in the initial state during a cold start of the internal combustion engine (2), wherein the valve (4) can be switched to an at least partially opened sequential state depending on an exhaust gas mass flow emitted by the internal combustion engine (2), and wherein a control device (6) determines an integral of the exhaust gas mass flow with respect to the time and switches the valve (4) into the sequential state when an integral threshold value is exceeded.

Claims

1. An arrangement, comprising: a coolant circuit for an internal combustion engine; a heat sink disposed in the coolant circuit; a valve disposed in the coolant circuit, said valve being configured to assume a closed state to bar a circulation of coolant between the internal combustion engine and the heat sink during a cold start of the internal combustion engine, and an open state allowing the circulation of coolant; and a control device configured to determine an integral of an exhaust gas mass flow emitted by the internal combustion engine with respect to time and to switch the valve to an at least partially open state disposed between the closed state and the open state, when the integral exceeds a threshold value.

2. The arrangement of claim 1, wherein the control device is configured to determine the exhaust gas mass flow from an injection amount of a fuel.

3. The arrangement of claim 2, wherein the control device is configured to determine the injection amount per unit of time.

4. The arrangement of claim 1, wherein the valve is part of a coolant pump or is formed by a coolant pump.

5. A method of operating a coolant circuit for an internal combustion engine, comprising: switching a valve to a closed initial state during a cold start of the internal combustion engine to prevent circulation of coolant between the internal combustion engine and a heat sink; continuously determining values of an exhaust gas mass flow emitted by the internal combustion engine beginning from the cold start of the internal combustion engine; forming an integral of the determined values with respect to time; and switching the valve to an at least partially open state disposed between the closed state and an open state, allowing the circulation, when the integral exceeds a threshold value.

Description

(1) It is shown in the drawings:

(2) FIG. 1 a schematic view of a coolant circuit for an internal combustion engine;

(3) FIG. 2 is a diagrammatic illustration of the exhaust gas mass flow over time.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(4) According to FIG. 1, a coolant circuit 1 for an internal combustion engine 2 has a heat sink 3. The heat sink 3 is circulated by ambient air on one hand, and coolant on the other hand. As a result of the realized heat exchange, coolant circulating in the coolant circuit 1 cools down. The coolant circulation is implemented by a coolant pump 5, with a switchable valve 4 being able to stop the coolant circulation. The internal combustion engine 2 has multiple combustion chambers 2c in which fuel is combusted so that the internal combustion engine 2 is heated. The generated heat can be dissipated by the coolant to the heat sink 3. The fuel is injected either into the intake system 2a or directly into the combustion chambers 2c and then mixed with intake air. Spent fuel-air mixture is expelled through the exhaust system 2b. A control device 6 ascertains the amount of injection of fuel per unit of time and determines the exhaust gas mass flow through the exhaust system 2b. The control device 6 forms an integral of the exhaust gas mass flow over time, as shown in FIG. 2. During a cold start of the internal combustion engine 2, that is, at the start at a coolant temperature which approximately corresponds to the ambient temperature, the valve 4 is in its closed starting condition and there is no coolant circulation. The control device 6 begins at the same time with a continuous computation of the integral value and causes the valve 4 to at least open in part as soon as the integral value exceeds a defined integral threshold value.

(5) According to the FIG. 2, the integral value is formed in that the emitted exhaust gas mass flow per unit of time t.sub.x is ascertained and integrated until the integral threshold value is exceeded.