DE102009001129A1 - Cooling strategy for internal combustion engines, involves dividing medium cycle into cylinder head side and block sided coolant jacket, where coolant control valve is provided, which prevents coolant flow to block sided coolant jacket - Google Patents

Abstract

The cooling strategy (2) involves dividing a medium cycle into a cylinder head side and a block sided coolant jacket. A coolant control valve is provided, which prevents the flow of coolant to the block sided coolant jacket and releases until a predetermined temperature is reached. A warm-up model of the combustion engine is implemented in a control unit for receiving the temperature during a start of the combustion engine and operating data of the internal combustion engine and for determining a heat input from the received temperature and the received operating data (6).

Description

The Invention relates to a cooling strategy for internal combustion engines, which have at least one medium circuit, which in a Block side coolant jacket and in at least one cylinder head side Coolant jacket is divided, wherein a coolant control valve is provided, which a coolant flow to the coolant jacket block first and only when it reaches a predetermined temperature releases.

to Improvement of the warm-up behavior of the internal combustion engine comes Increases the principle of split-cooling used, so the division the coolant circuit in a block-side and in at least one cylinder-side coolant circuit. The at least one cylinder head cooling circuit can also be referred to as the first partial circuit, wherein the block cooling circuit can also be referred to as a second subcircuit. The cylinder head side Circuit can be divided into other subcircuits. In split-cooling systems will be during the warm-up phase of the internal combustion engine, the medium flow through the cylinder block (the second partial circuit) by means of a control valve, for example a thermostat selectively interrupted, leaving coolant not by the block, but exclusively by the block Cylinder head is flowing. Is the warm-up phase completed, or the coolant reaches a certain temperature level, the block cycle is opened. The warm-up phase of the Internal combustion engine is the phase at which the internal combustion engine is started after a long standstill (cold start) and lasts until the internal combustion engine reaches its operating temperature or the cooling liquid a sufficient temperature level has reached.

modern Motors with a split-cooling concept therefore have at least two internal engine cooling circuits. The first (cylinder head cycle) is always flows through and the second (block cycle) if necessary hooked up. As a rule, it is located in the first coolant circuit a control valve in the embodiment as a conventional wax thermostat, which the second cooling circuit on / off and means the cooling water temperature of the first circuit controlled becomes.

at This configuration causes the problem that the controller regardless of the temperature of the second (block side) Circulation takes place. The second cycle is usually the one used for the cooling of the cylinder tubes (and indirectly also for the pistons and piston rings) is.

Become the engine after the cold start demands directly high loads, then the cooling water heats up in the second cycle (Block cycle) much faster than the coolant in the first cycle (cylinder head cycle). That reacts to that Wax element delays and it can easily lead to local overheating come in the second cooling circuit, which is not desirable are.

reinforced will this phenomenon when in the first cycle registered energy through other heat exchangers such. B. the cabin heater or the oil cooler used and thereby the coolant temperature is not at all or increased slowly. The coolant temperature in the first cycle is therefore smaller than the opening temperature of the wax thermostat, so that the second circuit is not connected although the heat input remains high is and so overheating in structure and coolant can lead.

The same thing Problem also occurs when instead of the conventional thermostat an electrically controlled control valve is used. This points Although in addition the possibility of control by an engine control unit (ECU), but usually the additional temperature measurement takes place at a critical temperature Place under warm full load conditions (eg cylinder head) or in the constantly flowed through part of the coolant flow and not at a point during the warm-up phase is critical.

Coolant circuits according to the split-cooling concept are for example in the EP 06 120 586 and the DE 10 2008 005 231 disclosed.

Of the The invention is therefore based on the object of a cooling strategy to improve the input type with simple means so that increased safety against overheating, in particular during a cold start of the internal combustion engine or in its Warm-up phase is reached when in the warm-up phase high loads be requested.

According to the invention the object is achieved by a cooling strategy having the features of claim 1, comprising
a warm-up model implemented in a controller,
picking up at least one temperature at a start of the internal combustion engine,
the recording of operating data of the internal combustion engine,
Determining a heat input from the recorded temperature and the recorded operating data,
estimating the amount of heat input from the determined heat input, and
the control of the control valve when a threshold value is reached.

Is useful in the context of the invention, when the warm-up model is implemented in the engine control. A warm-up model in the sense of the invention is stored in the control unit, and represents model-like thermal conditions of the internal combustion engine with different operating behavior. Of course, the warm-up model, based on the engine control unit (ECU), can also be provided externally as a separate control module.

at At the engine start, as the at least one temperature, the coolant temperature becomes or reference temperature measured.

After that a calculation of the heat input into the internal combustion engine takes place or in subregions of the engine or the temperature level in the engine or in its subareas.

To can operate data or input variables the internal combustion engine such as engine speed, engine load, output torque, fuel quantity and / or air demand used become.

Advantageous are then the registered amounts of heat and / or component temperatures and / or Coolant temperatures predicted or estimated.

better Way can such a critical temperature level in areas that not controlled by a direct temperature measurement monitored become.

One Adjustment of the model by means of the reference temperature is used for adjustment between calculation and reality.

As soon as predefined threshold values or critical values in the calculation and / or reached and / or exceeded during the measurement be a control of the electric thermostat or Coolant control valve, so this opens. Then the block-side cooling jacket is flowed through with coolant, although the actual warm-up phase is still ongoing. In other words, the split-cooling concept for this Case at short notice, that is, given up without delay, to protect the combustion engine from thermal damage.

Especially advantageous in the cooling strategy according to the invention is that no additional sensors are used need, but the already existing sensors used can be. Especially in the direct demand of high Loads directly after a cold start of the engine is like this ensures increased safety against overheating, because the second coolant circuit (block jacket) in time essentially undelayed to the expected increase Temperature adapted to be flowed through.

The Cooling strategy according to the invention is suitable preferred only in the case of a high load request during the cold start of the internal combustion engine. Will be recognized, that such a condition during the warm-up phase not is present, the warm-up of the internal combustion engine after the split cooling Procedure continued. Of course it will the split-cooling procedure is also carried out after a renewed cold start, unless the values determined on the basis of the warm-up model require the task of split cooling procedure.

Further advantageous embodiments of the invention are in the subclaims and the following description of the figures. It shows the only one

1 a flowchart of the cooling strategy according to the invention.

1 shows a basic flowchart 1 the cooling strategy according to the invention 2 ,

The cooling strategy 2 is preferably carried out on an internal combustion engine with a so-called split-cooling concept. In this, the internal combustion engine has a block-side coolant jacket and a cylinder-head-side coolant jacket. Preferably, a control valve in a Wasserauslaßgehäuse, that is connected to the cylinder head, separate component is arranged, wherein the control valve in the preferred embodiment as a thermostat, the total volume flow of the coolant z. B. controls for cooling and heating. The control valve may also be arranged in the cylinder head side coolant jacket. Of course, the control valve may also be arranged at other suitable locations, provided that a flow of coolant through the block-side coolant jacket during a warm-up phase or after a cold start of the internal combustion engine can be prevented. In the block itself further thermostat can be arranged, which influences the flow of coolant through the block.

It is possible that high loads are requested in the warm-up phase of the internal combustion engine. In order to protect the internal combustion engine from thermal damage during a cold start with simultaneous high load requirement, it is provided that at a start (block 3 ) of the internal combustion engine, a coolant temperature or reference temperature (block 4 ) to eat.

At the same time become a block 5 Operating data supplied to the internal combustion engine. As Be For example, engine speed, engine load, output torque, fuel quantity and / or air demand may be used.

The block 4 and block 5 data supplied to a block 6 supplied, in which a heat input in the internal combustion engine or in its sub-regions or the temperature level in the internal combustion engine or in its sub-regions is determined or calculated.

The ones in the block 6 Determined values become one block 7 supplied, in which the registered amounts of heat and / or component temperatures and / or coolant temperatures are predicted or estimated.

The ones in the block 7 Predicted values become a decision block 8th fed, in which at least one threshold for the internal combustion engine is stored. Thus, in the decision block 8th a trend of temperature evolution is detected, with immediate intervention being decided upon if necessary. Exceed those in the block 7 predicted values in block 8th At least one stored threshold, or are the values or amounts equal, a signal for opening the control valve is generated, so that the block jacket is flowed through with coolant, although the warm-up phase is not yet finished. This advantageously be cooled critical areas of the engine which could otherwise suffer thermal damage.

Returns the check in block 8th that the at least one threshold is not reached becomes a second decision block 9 decided if the warm-up phase is complete. If this is the case, the control valve by means of a block 9 signal generated. If the warm-up phase is not over yet, it will become block 3 jumped back, which of course does not mean that the engine is restarted, but the flowchart starting at block 4 and 5 to go through again.

In a further advantageous embodiment can be provided, via a further, not shown block dissipated amounts of heat in the cooling strategy 2 to be included. Heat can z. B. in radiators, heat exchangers, heat exchangers (such as oil / water, water / oil, water / water and / or oil / oil heat exchanger), hoses and dissipated via the heat dissipation of the entire system. For this purpose, a calculation model for determining the heat output and / or optionally a sensor system for measuring the heat flows or for measuring auxiliary variables can be used to determine or calculate the heat flows.

By way of example, heat can be introduced into the cooling system in a targeted manner by means of an electric block-water heating element, a parking heater and / or other heating elements, as a result of which the heating-up behavior can be correspondingly influenced. In this respect may be provided in a favorable manner, another, not shown block in the cooling strategy 2 to implement, so that the possibly influencing amounts of heat in the cooling strategy 2 can flow into it.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 06120586 [0008]
• - DE 102008005231 [0008]

Claims (6)

Cooling strategy for internal combustion engines, which identify at least one medium cycle, in at least a cylinder head side and a block side coolant jacket is divided, wherein a coolant control valve provided which is a coolant flow to the block side First shuts off coolant jacket and first upon reaching a predetermined temperature releases, comprising one Warm-up model of the internal combustion engine in a control unit is implemented picking up at least one temperature at a start of the internal combustion engine, the recording of operating data of the internal combustion engine, Determining a heat input from the recorded temperature and the recorded operating data, the Estimating the registered amount of heat from the determined heat input, and driving the Coolant control valve when a threshold value is reached. Cooling strategy according to claim 1, characterized in that that at the start of the internal combustion engine, a coolant temperature or reference temperature is measured. Cooling strategy according to claim 1 or 2, characterized characterized in that as operating data or input variables an engine speed, an engine load, an output torque, received a requested amount of fuel and / or an air requirement or measured. Cooling strategy according to one of the preceding claims, characterized in that after the determination of the heat input the registered amounts of heat, component temperatures and / or coolant temperatures be predicted or estimated. Cooling strategy according to one of the preceding claims in which dissipated amounts of heat in coolers, Heating heat exchangers, heat exchangers, hoses and about the heat radiation of the whole system incorporated. Cooling strategy according to one of the preceding claims in which amounts of heat from heating elements flow.