JP5899835B2 - Engine cooling system - Google Patents

Description

  The present invention includes a supercharger that supercharges air to an engine, an intercooler that cools air compressed by the supercharger, an electric pump that distributes cooling water to the supercharger and the intercooler, and A radiator that cools the cooling water that has passed through the supercharger or the intercooler, a first cooling water passage that passes the cooling water from the electric pump to the radiator via the supercharger, and the electric pump The present invention relates to an engine cooling device including a second cooling water passage for allowing the cooling water to flow through the radiator via an intercooler.

Conventionally, in order to increase the combustion efficiency of the engine, various ideas have been made on the intake system of the engine.
For example, Patent Document 1 describes a technique for promoting fuel atomization regardless of the engine temperature state. This technique actively heats the intake air in order to facilitate atomization of the fuel, particularly when the engine has not been warmed up. That is, unburned fuel in the exhaust gas is burned in the unburned fuel combustion chamber, and heat generated thereby is applied to the intake air by the heat exchanger, so that the temperature of the intake air is increased even when the engine is still cold. (For example, refer to Patent Document 1).

  Further, in order to increase the combustion efficiency of the engine, it is necessary to reduce the pumping loss. Pumping loss refers to energy loss that occurs when air is supplied to or exhausted from a cylinder such as a reciprocating engine. For example, when the opening degree of the throttle valve is small, the pumping loss increases because the throttle valve becomes a resistance against the intake flow inside the intake pipe. In a general electronic control type engine, when the warm-up of the engine has not been completed and the intake air temperature is low, the throttle valve is controlled to be throttled compared to when the intake air temperature is high. This is because when the intake air temperature is lower, the air density is larger, and when the engine speed is the same and the required air amount is the same, the throttle valve is throttled as the intake air temperature is lower. As a result, the pumping loss often increases when the warm-up operation of the engine is not completed.

JP-A-6-33840

In the technique of the known document 1, it is necessary to separately provide the unburned fuel combustion chamber and the heat exchanger. For this reason, the apparatus configuration becomes complicated.
Further, the engine of the known document 1 is a naturally aspirated engine that does not include a supercharger or an intercooler, and the internal pressure of the intake pipe does not increase so much, so it is considered that the effect of the pumping loss is small.

In this regard, in an engine with a supercharger, the supercharger functions effectively only during high output operation. Therefore, in the conventional turbocharged engine, many proposals have been made for improving the combustion efficiency during high-load operation. However, much attention has not been paid to improving the combustion efficiency when the engine temperature is low and the load is low.
Even in such an engine with a supercharger, although it is considered effective to heat the intake air immediately after the engine is started to increase the combustion efficiency, there has been no technology for heating the intake air until now.
Thus, in view of the above-described problems of the prior art, an object of the present invention is to obtain an engine that can improve combustion efficiency regardless of the operating state of the engine in an engine including a supercharger and an intercooler.

A first characteristic configuration of an engine cooling device according to the present invention includes a supercharger that supercharges air supplied to the engine, an intercooler that cools air compressed by the supercharger, the supercharger, and the supercharger. An electric pump for circulating cooling water through the intercooler, a radiator for cooling the cooling water flowing through the supercharger or the intercooler, and the cooling water from the electric pump to the radiator via the supercharger A first cooling water passage that allows the cooling water to flow from the electric pump to the radiator through the intercooler, and the cooling water that has passed through the supercharger bypasses the radiator. A bypass passage for recirculating the electric pump, and a passage arrangement for flowing the cooling water of the first cooling passage to the bypass passage when the intake air temperature is lower than the target temperature. Comprising a mechanism, wherein the when the supercharger becomes a temperature greater than or equal to the preset the start the electric pump, the channel setting mechanism is configured to circulate the cooling water in the bypass passage It is in a certain point.

The engine cooling device of this configuration includes a bypass flow path that recirculates the cooling water flowing through the supercharger to the electric pump by bypassing the radiator, and the cooling water in the first cooling water path when the intake air temperature is lower than the target temperature. And a flow path setting mechanism that circulates in the bypass flow path.
For this reason, at the time of low load operation of the engine, the cooling water whose temperature has risen through the supercharger can be recirculated to the electric pump without being cooled by the radiator and can be distributed to the intercooler.

Therefore, with the engine cooling device of this configuration, the engine combustion efficiency can be improved by using the intercooler to increase the intake air temperature during low-load operation of the engine.
In particular, in an engine that controls the throttle valve opening according to the amount of intake air (accelerator depression amount), the control is performed to increase the throttle valve opening by increasing the intake air temperature during low-load operation of the engine. Loss is reduced.
Also, with this configuration, since the electric pump is stopped when the temperature of the supercharger is lower than a preset temperature, the supercharger is not cooled by the cooling water, and the supercharger is quickly raised in temperature. be able to.
If the supercharger is in a state higher than the preset temperature, the cooling water after flowing through the supercharger is circulated through the bypass flow path, so that the intake air temperature is appropriately controlled while operating the electric pump efficiently. Can do.

  According to a second characteristic configuration of the present invention, the flow path setting mechanism is capable of adjusting the flow rate of cooling water from the first cooling water channel and the second cooling water channel to the radiator downstream of the branch portion of the bypass flow channel. The point is that it is a valve.

If it is this structure, the cooling water flow from the 1st cooling water channel and the 2nd cooling water channel to a radiator will be adjusted with an on-off valve in the downstream of the branch part of a bypass flow path, and the cooling water which distribute | circulated the supercharger and the intercooler The whole amount or a part of can be returned to the electric pump without being cooled by the radiator.
As a result, the intake air temperature can be appropriately controlled even immediately after the engine is started.

  A third characteristic configuration of the present invention is that the flow path setting mechanism is a flow path switching valve that allows the cooling water in the first cooling water path and the second cooling water path to flow through the bypass flow path.

  If it is this structure, since the whole quantity of the cooling water which distribute | circulated the supercharger and the intercooler can be recirculated to an electric pump, without cooling with a radiator, intake temperature can be raised still more efficiently.

It is a block diagram which shows the cooling device of an engine. It is a flowchart which shows the control action of a control apparatus. (A) is a graph which shows the time-dependent change of the supercharger exit water temperature at the time of warming-up operation in the engine cooling device of 1st Embodiment, the intercooler exit water temperature, and the intake air temperature. (B) is a graph which shows the time-dependent change of the supercharger outlet water temperature, the intercooler outlet water temperature, and the intake air temperature during the warm-up operation in the conventional engine cooling device. It is a block diagram which shows the cooling device of the engine of 2nd Embodiment. It is a flowchart which shows the control action of the control apparatus in 2nd Embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing a cooling device for an engine according to the present invention installed in an automobile engine.
The engine 1 includes a supercharger (turbocharger) 2 that supercharges air supplied to the engine 1 and an intercooler 3 that cools air compressed by the supercharger 2.
The supercharger 2 is integrally connected to an engine block of the engine 1 or the like.

  The engine cooling device includes an engine side cooling circuit 4 for cooling the engine 1 and a supercharger side cooling circuit 5 for cooling the supercharger 2 and the intercooler 3.

  The engine-side cooling circuit 4 operates the mechanical pump 6 by driving the engine 1 to circulate cooling water across the engine 1, the main radiator 7 and the heater 8.

  The supercharger-side cooling circuit 5 includes an electric pump 9 that circulates cooling water to the supercharger 2 and the intercooler 3, a sub-radiator 10 that cools the cooling water that has circulated through the supercharger 2 or the intercooler 3, The temperature of the intake air passing through the intercooler 3 during the low load operation of the engine 1 such as during the warm-up operation (first cooling water channel 11 for cooling the feeder 2, second cooling water channel 12 for cooling the intercooler 3) And a control device 14 for controlling the intake air temperature to be within a set range.

  The cooling water discharge passage 15 of the electric pump 9 is branched into the first cooling water passage 11 and the second cooling water passage 12, and the first cooling water passage 11 and the second cooling water passage 12 are joined to the cooling water inflow passage 16 of the sub radiator 10. I'm allowed.

The first cooling water channel 11 allows the cooling water to flow from the electric pump 9 to the sub radiator 10 via the supercharger 2.
The second cooling water passage 12 allows the cooling water to flow from the electric pump 9 to the sub radiator 10 via the intercooler 3.

  A bypass flow path 17 is branched at an intermediate position of the cooling water inflow path 16 to recirculate the cooling water flowing through the supercharger 2 to the electric pump 9 by bypassing the sub radiator 10.

  The cooling water inflow path 16 includes a flow path setting mechanism 13 that causes the cooling water of the first cooling water path 11 to flow through the bypass flow path 17 during low-load operation of the engine 1.

  The flow path setting mechanism 13 includes an on-off valve 13 a that can adjust the flow rate of the cooling water from the first cooling water path 11 and the second cooling water path 12 to the sub radiator 10 downstream of the branch portion of the bypass flow path 17. 16 is connected to the downstream portion of the branch passage 17 of the bypass flow path 17.

  The on-off valve 13a is configured as a two-position switching type electromagnetic valve that is maintained in a valve-open state maintained in a non-energized state when the engine is stopped and is switched to a valve-closed state that shuts off the flow of cooling water when energized.

  Therefore, if the on-off valve 13a is maintained in a non-energized state, the cooling water in the first cooling water channel 11 and the second cooling water channel 12 can be caused to flow into the sub-radiator 10, and the on-off valve 13a is maintained in an energized state. As a result, the entire amount of the cooling water in the first cooling water channel 11 and the second cooling water channel 12 can be recirculated to the electric pump 9 by bypassing the sub radiator 10.

The control operation by the control device 14 will be described with reference to the flowchart shown in FIG.
The control device 14 controls the operation of the on-off valve 13a so that the temperature of the intake air passing through the intercooler 3 (intake air temperature) becomes a temperature within a set range during low load operation such as during warm-up operation of the engine. .

When the engine 1 is started by turning on the ignition (step # 1), it is determined whether or not the temperature of the supercharger 2 is equal to or higher than a set temperature (step # 2).
This set temperature is set in advance as the temperature of the supercharger 2 that can effectively increase the intake air temperature by circulating the cooling water after flowing through the supercharger 2 to the bypass flow path 17. .

When the temperature of the supercharger 2 is equal to or higher than the set temperature, after the operation of the electric pump 9 is started (step # 3), it is determined whether the intake air temperature is within the target temperature range (step # 3). # 4) When the temperature is not within the target temperature range, it is determined whether the temperature is less than the target temperature range (step # 5).
The target temperature range of the intake air temperature is set in advance as a temperature range that can effectively reduce the pumping loss.

  When the intake air temperature is lower than the target temperature range, the on-off valve 13a is maintained in the energized state and held in the closed state, and the total amount of cooling water in the first cooling water channel 11 and the second cooling water channel 12 is maintained. The sub-radiator 10 is bypassed and recirculated to the electric pump 9 (step # 6).

  When the engine 1 is stopped by the ignition OFF operation (step # 7), the electric pump 9 is stopped (step # 9), and the control operation is finished in the open state in which the on-off valve 13a is maintained in the non-energized state. .

  When the intake air temperature is within the target temperature range at step # 4 and when the intake air temperature is not below the target temperature range at step # 5, that is, when the temperature exceeds the target temperature range, the opening / closing is performed. By maintaining the valve 13a in a non-energized state, the valve 13a is kept open (step # 8), and it is determined whether or not the engine 1 has been stopped (step # 7).

  When it is determined in step # 7 that the engine 1 is not stopped, steps # 4 to # 8 are periodically repeated at set time intervals until the engine 1 is stopped.

  FIG. 3A shows temporal changes in the supercharger outlet water temperature, the intercooler outlet water temperature, and the intake air temperature during the warm-up operation by the cooling device of the present embodiment, and FIG. The change with time of the supercharger outlet water temperature, the intercooler outlet water temperature, and the intake air temperature during the warming-up operation by the conventional cooling device not provided is shown.

According to the cooling device of the present embodiment, as shown in FIG. 3A, any of the rates of increase in the supercharger outlet water temperature, the intercooler outlet water temperature, and the intake air temperature is the conventional cooling shown in FIG. It is larger than the rate of increase of the supercharger outlet water temperature, intercooler outlet water temperature and intake air temperature by the device, indicating that the intake air temperature is rising efficiently.
The peak of the supercharger outlet water temperature at the start of operation of the electric pump 9 is caused by the fact that the supercharger 2 has not been cooled until the operation of the electric pump 9 is started after the engine 1 is started.

[Second Embodiment]
4 and 5 show another embodiment of the present invention.
In this embodiment, instead of the on-off valve 13a shown in the first embodiment, as shown in FIG. 4, the first cooling water passage 11 and the second cooling water are provided at a branch point of the bypass flow passage 17 in the cooling water inflow passage 16. A flow path switching valve 13 b for circulating the cooling water of the water path 12 to the bypass flow path 17 is provided as the flow path setting mechanism 13.

The flow path switching valve 13 b connects the first cooling water path 11 and the second cooling water path 12 to the sub-radiator 10 and blocks communication between the first cooling water path 11 and the second cooling water path 12 and the bypass flow path 17. The first connection state, the connection between the first cooling water channel 11 and the second cooling water channel 12 and the sub-radiator 10 are cut off, and the first cooling water channel 11, the second cooling water channel 12 and the bypass flow channel 17 are communicated with each other. The solenoid valve can be switched selectively to the second connection state.
The flow path switching valve 13b is maintained in the first connection state maintained in the non-energized state when the engine is stopped, and is switched to the second connection state by energization.

  Therefore, if the flow path switching valve 13b is maintained in a non-energized state, the entire amount of cooling water flowing through the first cooling water path 11 and the second cooling water path 12 flows through the sub-radiator 10, and the flow path switching valve 13b is switched on. When maintained, the entire amount of the cooling water flowing through the first cooling water channel 11 and the second cooling water channel 12 is returned to the electric pump 9 via the bypass channel 17.

  The control device 14 replaces the operation of holding the on-off valve 13a in step # 6 of the flowchart (FIG. 2) shown in the first embodiment with the valve closed, as shown in the flowchart of FIG. 13b is maintained in the energized state and held in the second connection state.

Further, in place of the operation of holding the on-off valve 13a in the open state in Step # 8 of the flowchart (FIG. 2) shown in the first embodiment, as shown in the flowchart of FIG. The energized state is maintained and the first connected state is maintained.
Other configurations are the same as those of the first embodiment.

[Other Embodiments]
1. The engine cooling device according to the present invention includes a flow path setting mechanism 13 that allows the entire amount of cooling water in the first cooling water path 11 to flow only to the bypass flow path 17 when the intake air temperature is lower than the target temperature. A flow path setting mechanism 13 that circulates the part to the bypass flow path 17 may be provided.
2. The engine cooling device according to the present invention may include a flow path setting mechanism 13 that allows only the cooling water that has flowed through the supercharger 2 to flow through the bypass flow path 17 when the intake air temperature is lower than the target temperature.
3. In the engine cooling apparatus according to the present invention, each of the first cooling water passage 11 and the second cooling water passage 12 may be connected to the sub-radiator 10 separately.
4). The engine cooling device according to the present invention may be configured such that the radiator that cools the cooling water flowing through the supercharger 2 or the intercooler 3 is a radiator that cools the cooling water circulated by the mechanical pump 6.
5). The engine cooling device according to the present invention may be installed in various engines other than automobile engines.

  The engine cooling device according to the present invention can be applied to various engines other than automobile engines.

DESCRIPTION OF SYMBOLS 1 Engine 2 Supercharger 3 Intercooler 9 Electric pump 10 Radiator 11 1st cooling water channel 12 2nd cooling water channel 13 Channel setting mechanism 13a On-off valve 13b Channel switching valve 17 Bypass channel

Claims (3)

A supercharger for supercharging the air supplied to the engine;
An intercooler for cooling the air compressed by the supercharger;
An electric pump for circulating cooling water through the supercharger and the intercooler;
A radiator that cools the cooling water that has passed through the supercharger or the intercooler;
A first cooling water channel for circulating the cooling water from the electric pump to the radiator via the supercharger;
A second cooling water channel for circulating the cooling water from the electric pump to the radiator via the intercooler;
A bypass flow path for recirculating the cooling water flowing through the supercharger to the electric pump by bypassing the radiator;
A flow path setting mechanism for circulating the cooling water of the first cooling water path to the bypass flow path when the intake air temperature is lower than the target temperature ,
An engine cooling apparatus configured to start the electric pump when the supercharger reaches a preset temperature or more and cause the flow path setting mechanism to flow the cooling water to the bypass flow path. .   2. The on-off valve according to claim 1, wherein the flow path setting mechanism is an on-off valve capable of adjusting a cooling water flow rate from the first cooling water path and the second cooling water path to the radiator downstream of a branch portion of the bypass flow path. Engine cooling system.   2. The engine cooling device according to claim 1, wherein the flow path setting mechanism is a flow path switching valve that circulates cooling water of the first cooling water path and the second cooling water path to the bypass flow path.

Images