JP7359103B2 - engine equipment - Google Patents

Description

The present invention relates to an engine device, and more particularly to an engine device including an engine, a supercharger, and an intercooler.

BACKGROUND ART Conventionally, as this type of engine device, one including an engine (engine main body), a supercharger (turbocharger), and an intercooler has been proposed (see, for example, Patent Document 1). The supercharger includes a turbine and a compressor. The turbine is located in the exhaust pipe of the engine. The compressor is placed in the intake pipe of the engine and is driven by a turbine. The intercooler is arranged downstream of the compressor in the intake pipe, and cools the air in the intake pipe using a cooling medium. This device includes an EGR pipe, an EGR valve, and an EGR cooler. The EGR pipe branches from the exhaust pipe upstream of the turbine and connects to the intake pipe downstream of the compressor. The EGR valve opens and closes the EGR pipe. The EGR cooler is arranged upstream of the EGR valve in the EGR pipe, and cools the air in the EGR pipe using a cooling medium. This device includes a bypass pipe that branches from the downstream side of the compressor in the intake pipe and connects between the EGR cooler and the EGR valve in the EGR pipe, and a bypass valve that opens and closes the bypass pipe. Then, by closing the EGR valve and opening the bypass valve, a portion of the supercharged air supercharged by the compressor is supplied to the EGR pipe via the bypass pipe, and is deposited at the EGR cooler position in the EGR pipe. Blow off deposits such as soot. This suppresses deposits from accumulating at the EGR cooler position in the EGR pipe.

Japanese Patent Application Publication No. 2007-92618

Although the above-mentioned engine device can suppress the accumulation of deposits in the EGR pipe, it cannot suppress the accumulation of condensed water generated when the air in the intake pipe is cooled by the intercooler. If the condensed water accumulated in this way enters the cylinder of the engine, problems such as misfires may occur. Therefore, it is desired to suppress the accumulation of condensed water within the intake pipe.

The main purpose of the engine device of the present invention is to suppress the accumulation of condensed water in the intake pipe.

The engine device of the present invention employs the following means to achieve the above-mentioned main purpose.

The engine device of the present invention includes:
engine and
A turbine disposed in an exhaust pipe of the engine, a compressor disposed in an intake pipe of the engine and driven by the turbine, and a bypass pipe connecting upstream and downstream sides of the compressor in the intake pipe. an air bypass valve provided;
an intercooler that is disposed downstream of the compressor and the air bypass valve in the intake pipe and cools the air in the intake pipe using a cooling medium; a control device that controls the engine and the air bypass valve;
An engine device comprising:
The control device is configured such that an accumulated amount of condensed water, which is an accumulated amount of condensed water generated in the intake pipe when the air in the intake pipe is cooled by the intercooler, is a moisture content in the intake pipe that causes a misfire in the engine. When the amount is equal to or greater than the misfire limit amount as the lower limit value of the amount, execute a first control to open the air bypass valve;
After executing the first control, the amount of condensed water generated in the intake pipe due to the air in the intake pipe being cooled by the intercooler is increased by the amount of condensed water generated in the intake pipe due to the flow of air in the intake pipe. When the amount of water blown away downstream from the intercooler in the pipe exceeds the amount of water taken away, the engine is controlled so that the ignition timing is later than a predetermined reference timing and the throttle opening is increased. This is the summary.

In the engine device of the present invention, the amount of accumulated condensed water generated in the intake pipe as the amount of accumulated condensed water in the intercooler when the air in the intake pipe is cooled by the intercooler is the amount of condensed water that is accumulated in the intake pipe where a misfire occurs in the engine. When the amount of moisture is equal to or greater than the misfire limit amount as the lower limit value of the moisture amount, the first control to open the air bypass valve is executed. By opening the air bypass valve, the air pressure downstream of the compressor in the intake pipe is reduced. As a result, the amount of water retained per unit volume of air downstream of the compressor in the intake pipe is reduced, so generation of condensed water due to cooling of the intercooler can be suppressed. After the first control is executed, the amount of condensed water generated in the intake pipe as a result of the air in the intake pipe being cooled by the intercooler is increased by the amount of condensed water generated in the intake pipe due to the flow of air in the intake pipe. When the amount of water taken away as the amount of water blown further downstream is exceeded, the engine may be controlled so that the ignition timing is later than a predetermined reference timing and the throttle opening is increased. Since the throttle opening is increased to increase the amount of air passing through the intake pipe, the amount of water removed can be increased. As a result, it is possible to suppress moisture from accumulating at the position of the intercooler in the intake pipe.

1 is a configuration diagram schematically showing the configuration of an engine device 10 as an example of the present invention. 7 is an explanatory diagram showing an example of input/output signals of the electronic control unit 70. FIG. 7 is a flowchart showing an example of a control routine executed by the electronic control unit 70. FIG. It is an explanatory diagram showing an example of a setting map.

Next, a mode for carrying out the present invention will be described using examples.

FIG. 1 is a block diagram schematically showing the structure of an engine device 10 as an embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of input/output signals of the electronic control unit 70. The engine device 10 of the embodiment is installed in a general automobile or various hybrid automobiles, and as shown in FIGS. 1 and 2, includes an engine 12, a supercharger 40, an intercooler 25, and an electronic control unit 70. Equipped with.

The engine 12 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel oil. This engine 12 sucks air purified by an air cleaner 22 into an intake pipe 23, passes it through an intercooler 25, a throttle valve 26, and a surge tank 27 in this order, and injects fuel downstream of the surge tank 27 in the intake pipe 23. Fuel is injected from the valve 28 to mix air and fuel. This air-fuel mixture is then sucked into the combustion chamber 30 through the intake valve 29, and exploded and combusted by the electric spark from the ignition plug 31. Then, the reciprocating motion of the piston 32, which is pushed down by the energy generated by the explosive combustion, is converted into the rotational motion of the crankshaft 14. Exhaust gas discharged from the combustion chamber 30 to the exhaust pipe 35 via the exhaust valve 34 is processed by a catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). ) is discharged to the outside air through purifiers 37, 38 having

The supercharger 40 is configured as a turbocharger and includes a compressor 41, a turbine 42, a rotating shaft 43, a wastegate valve 44, and an air bypass valve 45. Compressor 41 is arranged upstream of intercooler 25 in intake pipe 23 . The turbine 42 is disposed upstream of the purifying device 37 of the exhaust pipe 35. The rotating shaft 43 connects the compressor 41 and the turbine 42. The wastegate valve 44 is provided in a bypass pipe 36 that communicates between the upstream side and the downstream side of the turbine 42 in the exhaust pipe 35, and is controlled by the electronic control unit 70. The air bypass valve 45 is provided in the bypass pipe 24 that communicates between the upstream side and the downstream side of the compressor 41 in the intake pipe 23, and is controlled by the electronic control unit 70.

In this supercharger 40, by adjusting the opening degree of the waste gate valve 44, the distribution ratio between the amount of exhaust gas flowing through the bypass pipe 36 and the amount of exhaust gas flowing through the turbine 42 is adjusted, and the rotational driving force of the turbine 42 is adjusted. The amount of compressed air by the compressor 41 is adjusted, and the supercharging pressure (intake pressure) of the engine 12 is adjusted. Here, the distribution ratio is adjusted so that, in detail, the smaller the opening degree of the wastegate valve 44, the smaller the amount of exhaust gas flowing through the bypass pipe 36 and the larger the amount of exhaust gas flowing through the turbine 42. Note that when the wastegate valve 44 is fully open, the engine 12 can operate in the same manner as a naturally aspirated engine that does not include the supercharger 40.

In addition, in the supercharger 40, when the pressure downstream of the compressor 41 in the intake pipe 23 is higher than the pressure upstream to some extent, the air bypass valve 45 is opened. Excess pressure can be released. Note that the air bypass valve 45 is used instead of a valve controlled by the electronic control unit 70 as a check valve that opens when the pressure on the downstream side of the compressor 41 in the intake pipe 23 becomes higher than the pressure on the upstream side to some extent. It may be configured.

Intercooler 25 is arranged downstream of compressor 41 in intake pipe 23 . A cooling medium (for example, long life coolant (LLC), etc.) circulates in the intercooler 25. The intercooler 25 cools the air (intake air) in the intake pipe 23 by exchanging heat between the air (intake air) in the intake pipe 23 and a cooling medium.

The electronic control unit 70 is configured as a microprocessor centered on a CPU, and includes, in addition to the CPU, a ROM for storing processing programs, a RAM for temporarily storing data, an input/output port, and a communication port. Signals from various sensors are input to the electronic control unit 70 via input ports.

Signals input to the electronic control unit 70 include, for example, the crank angle θcr from the crank position sensor 14a that detects the rotational position of the crankshaft 14 of the engine 12, and the water temperature (not shown) that detects the temperature of the cooling medium of the engine 12. Examples include the temperature Tw of the cooling medium from the sensor and the throttle opening TH from the throttle position sensor 26a that detects the opening of the throttle valve 26. The cam position θca may be detected from a cam position sensor (not shown) that detects the rotational position of the intake camshaft that opens and closes the intake valve 29 and the exhaust camshaft that opens and closes the exhaust valve 34. The intake air amount Qa from the air flow meter 23a installed upstream of the compressor 41 in the intake pipe 23, the intake pressure Pin from the pressure sensor 23b installed upstream of the compressor 41 in the intake pipe 23, and the intake pipe 23, the supercharging pressure Pc from the pressure sensor 23c installed between the compressor 41 and the intercooler 25, and the intake temperature Tin from the temperature sensor 23d installed upstream of the compressor 41 in the intake pipe 23. Can be done. The surge pressure Ps from the pressure sensor 27a attached to the surge tank 27 and the surge temperature Ts from the temperature sensor 27b attached to the surge tank 27 can also be mentioned. Front air-fuel ratio AF1 from the front air-fuel ratio sensor 35a installed upstream of the purification device 37 in the exhaust pipe 35, and rear air-fuel ratio sensor installed between the purification device 37 and the purification device 38 in the exhaust pipe 35. The rear air-fuel ratio AF2 from 35b can also be mentioned. The external temperature Tatm from the temperature sensor 60 that detects the outside air temperature and the humidity Hatm from the humidity sensor 62 that detects the humidity outside the vehicle can also be cited.

Various control signals are output from the electronic control unit 70 via an output port. Examples of the signals output from the electronic control unit 70 include a control signal to the throttle valve 26, a control signal to the fuel injection valve 28, and a control signal to the spark plug 31. A control signal to the wastegate valve 44 and a control signal to the air bypass valve 45 can also be mentioned.

The electronic control unit 70 calculates the rotation speed Ne of the engine 12 based on the crank angle θcr from the crank position sensor 14a. Further, the electronic control unit 70 calculates the load factor (the air actually taken in in one cycle with respect to the stroke volume per one cycle of the engine 12) based on the intake air amount Qa from the air flow meter 23a and the rotation speed Ne of the engine 12. (volume ratio) KL is calculated. Furthermore, the electronic control unit 70 controls the intake air temperature Tinc on the upstream side of the intercooler 25 based on the intake pressure Pin from the pressure sensor 23b, the boost pressure Pc from the pressure sensor 23c, and the intake air temperature Tin from the temperature sensor 23d. (Temperature of intake air flowing into intercooler 25) is calculated.

In the engine device 10 of the embodiment configured in this way, the electronic control unit 70 controls the amount of intake air that controls the opening degree of the throttle valve 26 and controls the amount of air from the fuel injection valve 28 based on the required load factor KL* of the engine 12. ignition control that controls the ignition timing of the spark plug 31, supercharging control that controls the opening degree of the waste gate valve 44, etc.

In the intake air amount control, for example, the intake air amount QFe for fuel efficiency, which is determined to improve fuel efficiency based on the required load factor KL*, is set as the target intake air amount Qa*, and the intake air amount Qa is set to the target intake air amount. The target opening TH* of the throttle valve 26 is set so that Qa* is reached, and the throttle valve 26 is controlled so that the throttle opening TH becomes the target opening TH*.

For example, the fuel injection control sets the target fuel injection amount Qf* of the fuel injection valve 28 so that the front air-fuel ratio AF1 becomes the target air-fuel ratio AF* (for example, the stoichiometric air-fuel ratio) based on the intake air amount Qa, This is performed by controlling the fuel injection valve 28 using the set target fuel injection amount Qf*.

In the ignition control, for example, the fuel efficiency ignition timing TFe, which is determined to improve fuel efficiency based on the rotational speed Ne of the engine 12 and the required load factor KL*, is set as a reference timing TFb, and the reference timing TFb is set as the target ignition timing of the spark plug 31. This is done by setting the timing Tf* and controlling the spark plug 31 using the set target ignition timing Tf*.

Next, the operation of the engine device 10 of the embodiment configured as described above, particularly the operation when suppressing the accumulation of condensed water in the intake pipe 23, will be described. FIG. 3 is a flowchart showing an example of a control routine executed by the electronic control unit 70. This routine is repeatedly executed while the engine 12 is operating.

When this routine is executed, the CPU of the electronic control unit 70 executes a process of inputting the intake air amount Qa, boost pressure Pc, surge temperature Ts, outside temperature Tatm, and humidity Hatm (step S100). The intake air amount Qa is inputted as detected by the air flow meter 23a. The boost pressure Pc detected by the pressure sensor 23c is input. The surge temperature Ts detected by a temperature sensor 27b attached to the surge tank 27 is input. The outside temperature Tatm detected by the temperature sensor 60 is input. The humidity Hatm detected by the humidity sensor 62 is input.

After inputting the data necessary for processing in this way, the air in the intake pipe 23 is cooled by the intercooler 25 based on the intake air amount Qa, supercharging pressure Pc, surge temperature Ts, outside temperature Tatm, and humidity Hatm. The generated condensed water amount Vgcw is set as the amount of condensed water generated by this (step S110). The method for setting the generated condensed water amount Vgcw is as follows. First, the air density Daac and moisture content Vwac of the air introduced via the air cleaner 22 are derived using the outside temperature Tatm and the standard pressure (101.33 kPa). Next, the air density Daic after passing through the intercooler 25 is calculated using the surge temperature Ts and the supercharging pressure Pc. Then, using the calculated air density Daac, moisture amount Vwac, and air density Daic, the moisture amount Vwic contained in the air after passing through the intercooler 25 is calculated. From the water content Vwic calculated in this way, the larger value between the value 0 and the value 0 is calculated by subtracting the saturated water vapor content Vss at the outside temperature Tatm derived using the saturated steam amount curve and the outside temperature Tatm. Set the water amount to Vgcw.

Next, the amount of water taken away Vta and the misfire limit amount Vlim are set (step S120). The amount of water taken away Vta is the amount of water blown away from the intercooler 25 in the intake pipe 23 by the flow of air in the intake pipe 23 . The misfire limit amount Vlim is defined as whether or not a misfire will occur in the engine 12 when condensed water accumulated at the position of the intercooler 25 in the intake pipe 23 flows downstream from the intercooler 25 and enters the cylinder of the engine 12. This is a threshold value for determining whether or not a misfire occurs in the engine 12, and is a lower limit value of the amount of water at the position of the intercooler 25 in the intake pipe 23 at which a misfire occurs in the engine 12. The removal water amount Vta and the misfire limit amount Vlim are set using the intake air amount Qa and a setting map. The setting map is a map showing the relationship between the intake air amount Qa, the removed water amount Vta, and the misfire limit amount Vlim based on experiments, analysis, and the like. FIG. 4 is an explanatory diagram showing an example of a setting map. In the figure, a dashed line indicates an example of the relationship between the amount of water removed Vta and the amount of intake air Qa. The broken line shows an example of the relationship between the misfire limit amount Vlim and the intake air amount Qa. The solid line shows an example of the relationship between the generated condensed water amount Vgcw and the intake air amount Qa calculated in step S110. The removed water amount Vta and the misfire limit amount Vlim are set by deriving a value corresponding to the intake air amount Qa from the setting map.

When the generated condensed water amount Vgcw and the removed water amount Vta are set in this way, the removed water amount Vta is subtracted from the generated condensed water amount Vgcw, and the condensed water generated when the air in the intake pipe 23 passes through the intercooler 25 is The accumulated condensed water amount Vcw (=Vgcw−Vcta) as the accumulated amount at is calculated (step S130).

Subsequently, it is determined whether the accumulated condensed water amount Vcw is equal to or greater than the misfire limit amount Vlim (step S140). When the accumulated condensed water amount Vcw is less than the misfire limit amount Vlim, it is determined that there is a low possibility that a misfire will occur even if the condensed water accumulated at the position of the intercooler 25 of the intake pipe 23 flows downstream from the intercooler 25. Then, this routine ends.

If the accumulated condensed water amount Vcw is equal to or greater than the misfire limit amount Vlim in step S140, there is a possibility that a misfire will occur when the condensed water accumulated at the position of the intercooler 25 in the intake pipe 23 flows downstream from the intercooler 25. is determined to be high, and the air bypass valve 45 is opened (step S150). When the air bypass valve 45 is opened, the air pressure on the upstream side of the intercooler 25 in the intake pipe 23, that is, the supercharging pressure Pc decreases, so the amount of condensed water generated in the intercooler 25 (the amount of condensed water generated Vgcw) is reduced. be able to. Thereby, accumulation of condensed water in the intercooler 25 of the intake pipe 23 can be suppressed.

Next, in the same process as steps S100 and S110, the intake air amount Qa, boost pressure Pc, surge temperature Ts, outside temperature Tatm, and humidity Hatm are input (step S160), and the generated condensed water amount Vgcw is set (step S170). Then, the amount of water to be taken away Vta is set in the same process as the setting of the amount of water to be taken away Vta in step S120 (step S180).

Then, it is determined whether the generated condensed water amount Vgcw exceeds the removed water amount Vta (step S190). When the generated condensed water amount Vgcw exceeds the removed water amount Vta (for example, in the hatched area in FIG. 4), condensed water is accumulated at the position of the intercooler 25 in the intake pipe 23. Now, since the air bypass valve 45 is opened in step S150, if the generated condensed water amount Vgcw exceeds the removed water amount Vta, even if the air bypass valve 45 is opened, the intercooler of the intake pipe 23 It is considered that the accumulation of condensed water at No. 25 was not sufficiently suppressed. Therefore, the process in step S190 is a process for determining whether the accumulation of condensed water in the intercooler 25 of the intake pipe 23 is sufficiently suppressed by opening the air bypass valve 45.

When the generated condensed water amount Vgcw is equal to or less than the removed water amount Vta in step S190, the accumulation of condensed water in the intercooler 25 of the intake pipe 23 is sufficiently suppressed by opening the air bypass valve 45 in step S150. It is determined that this is the case, and this routine ends.

When the generated condensed water amount Vgcw exceeds the removed water amount Vta in step S190, the air bypass valve 45 is opened in step S150, but the accumulation of condensed water in the intercooler 25 of the intake pipe 23 has not been sufficiently suppressed. If it is determined that there is not, ignition retard control and throttle valve opening control are executed (step S200), and this routine ends.

In the ignition retard control, the target ignition timing Tf* of the spark plug 31 is set to a later (retarded) timing than the above-mentioned reference timing TFb (ignition timing TFe for fuel efficiency), and the set target ignition timing Tf* is used. This is done by controlling the spark plug 31 with the In the throttle valve opening control, the target intake air amount Qa* is set to the amount of air obtained by increasing the intake air amount QFe for fuel efficiency by a predetermined amount Qadd, and the throttle valve 26 is adjusted so that the intake air amount Qa becomes the target intake air amount Qa*. This is done by setting a target opening degree TH* of , and controlling the throttle valve 26 so that the throttle opening degree TH becomes the target opening degree TH*.

By executing the ignition retard control and the throttle valve opening control, the intake air amount Qa is increased and the removed water amount Vta is increased. Thereby, accumulation of condensed water in the intercooler 25 of the intake pipe 23 can be suppressed.

According to the engine device 10 of the embodiment described above, the accumulated condensed water amount Vcw, which is the accumulated amount of condensed water generated when the air in the intake pipe 23 is cooled by the intercooler 25, is such that a misfire occurs in the engine 12. When the amount of moisture in the intake pipe 23 is equal to or higher than the misfire limit amount Vlim as the lower limit value, the air bypass valve 45 is opened (the first control is executed), and thereafter (after the first control is executed). , the amount of condensed water Vgcw generated as the amount of condensed water generated when the air in the intake pipe 23 is cooled by the intercooler 25 is blown away from the intercooler 25 in the intake pipe 23 by the flow of air in the intake pipe 23. When the amount of water removed as the amount of condensed water is exceeded, the engine 12 is controlled so that the ignition timing is later than the reference timing TFb (ignition timing TFe for fuel economy) and the throttle opening TH is large. Accumulation of condensed water within 23 can be suppressed.

In the engine device 10 of the embodiment, the reference timing TFb of the ignition timing is set as the fuel efficiency ignition timing TFe. However, the reference timing TFb is not limited to the ignition timing TFe for fuel efficiency, and may be set at an appropriate timing according to the specifications of the engine device 10, such as an ignition timing for outputting large torque from the engine 12. .

The correspondence between the main elements of the embodiments and the main elements of the invention described in the column of means for solving the problems will be explained. In the embodiment, the engine 12 corresponds to an "engine", the turbine 42 corresponds to a "turbine", the compressor 41 corresponds to a "compressor", the air bypass valve 45 corresponds to an "air bypass valve", and supercharging The engine 40 corresponds to a "supercharger," the intercooler 25 corresponds to an "intercooler," and the electronic control unit 70 corresponds to a "control device."

The correspondence relationship between the main elements of the examples and the main elements of the invention described in the column of means for solving the problem is that the example implements the invention described in the column of means for solving the problem. Since this is an example for specifically explaining a form for solving the problem, it is not intended to limit the elements of the invention described in the column of means for solving the problems. In other words, the interpretation of the invention described in the column of means for solving the problem should be based on the description in that column, and the examples are based on the description of the invention described in the column of means for solving the problem. This is just one specific example.

Although the embodiments of the present invention have been described above using examples, the present invention is not limited to these examples in any way, and may be modified in various forms without departing from the gist of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICATION This invention can be utilized for the manufacturing industry of an engine device, etc.

Reference Signs List 10 engine device, 12 engine, 14 crankshaft, 14a crank position sensor, 22 air cleaner, 23 intake pipe, 23a air flow meter, 23b, 23c, 27a pressure sensor, 24, 36 bypass pipe, 25 intercooler, 26 throttle valve, 26a Throttle position sensor, 27 surge tank, 23d, 27b temperature sensor, 28 fuel injection valve, 29 intake valve, 30 combustion chamber, 31 spark plug, 32 piston, 34 exhaust valve, 35 exhaust pipe, 35a front air-fuel ratio sensor, 35b rear Air-fuel ratio sensor, 37, 38 Purifier, 40 Supercharger, 41 Compressor, 42 Turbine, 43 Rotating shaft, 44 Waste gate valve, 45 Air bypass valve, 60 Temperature sensor, 62 Humidity sensor, 70 Electronic control unit.

Claims (1)

engine and
A turbine disposed in an exhaust pipe of the engine, a compressor disposed in an intake pipe of the engine and driven by the turbine, and a bypass pipe connecting upstream and downstream sides of the compressor in the intake pipe. an air bypass valve provided;
an intercooler that is disposed downstream of the compressor and the air bypass valve in the intake pipe and cools the air in the intake pipe using a cooling medium; a control device that controls the engine and the air bypass valve;
An engine device comprising:
The control device is configured such that an accumulated amount of condensed water, which is an accumulated amount of condensed water generated in the intake pipe when the air in the intake pipe is cooled by the intercooler, is a moisture content in the intake pipe that causes a misfire in the engine. When the amount is equal to or greater than the misfire limit amount as the lower limit value of the amount, execute a first control to open the air bypass valve;
After executing the first control, the amount of condensed water generated in the intake pipe due to the air in the intake pipe being cooled by the intercooler is increased by the amount of condensed water generated in the intake pipe due to the flow of air in the intake pipe. An engine device that controls the engine so that the ignition timing is later than a predetermined reference timing and the throttle opening is increased when the amount of water blown away downstream from the intercooler in the pipe is exceeded. .

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