Control device for internal combustion engine

Abstract

To provide a control device for an internal combustion engine which can acquire a temperature of a housing of a compressor.SOLUTION: In a control device for an internal combustion engine including a supercharger, the supercharger has a compressor. The control device for the internal combustion engine includes a first acquisition part which acquires a temperature of air in the compressor, and a second acquisition part which acquires a temperature of a housing of the compressor.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for an internal combustion engine.

Background Art

[0002] An internal combustion engine equipped with a supercharger is known (for example, Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When deposits adhere to the compressor of the supercharger, the efficiency of the supercharger decreases. Whether deposits are generated depends on the temperature of the housing of the compressor. To predict the generation of deposits, it is important to know the temperature of the housing. Therefore, an object of the present invention is to provide a control device for an internal combustion engine capable of acquiring the temperature of the housing of the compressor.

Means for Solving the Problems

[0005] The above object is achieved by a control device for an internal combustion engine equipped with a supercharger, the supercharger having is provided in the intake passage of the internal combustion engine, a compressor, based on the temperature of the air introduced into the intake passage, the pressure at the inlet of the compressor, and the supercharging pressure of the air supercharged by the supercharger, the compressor the outlet portion of including a first acquisition unit for acquiring the temperature of the air in the compressor, and a second acquisition unit for acquiring the temperature of the housing of the compressor. at the outlet portion the temperature of the air , perform a heat transfer analysis on the housing of the compressor by using the intake air flow rate of the intake passage, the speed of the vehicle on which the internal combustion engine is mounted, and the temperature of the outside air, The control device for the internal combustion engine can achieve this. and the second acquisition unit, in the heat transfer analysis, assumes that the housing of the compressor is a plate-like substance, air having the temperature at the outlet portion flows on one side of the housing, and the running wind generated by the vehicle running flows on the other side of the housing, and calculates the heat conduction in the housing based on the heat capacity of the housing to obtain the temperature of the housing

Effects of the Invention

[0006] ​It is possible to provide a control device for an internal combustion engine that can acquire the temperature of the compressor housing.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0008] FIG. 1 is a schematic diagram illustrating an engine system 100. The engine system 100 includes an internal combustion engine 10, a supercharger 18, and an ECU (Electronic Control Unit) 50.

[0009] The internal combustion engine 10 is, for example, a gasoline engine or a diesel engine, and includes a piston 17, an intake valve 30, an exhaust valve 32, and a fuel injection valve 34. A combustion chamber 27 is formed in the bore of the internal combustion engine 10. The fuel injection valve 34 is provided in the intake passage 12, but may be provided in the combustion chamber 27. The piston 17 is disposed inside the combustion chamber 27 and is connected to the crankshaft 19.

[0010] An intake passage 12 and an exhaust passage 14 are connected to the internal combustion engine 10. In the intake passage 12, an air cleaner 20, an air flow meter 22, an intercooler 25, a throttle valve 26, and a fuel injection valve 34 are provided in order from the upstream side. A catalyst 28 is provided in the exhaust passage 14.

[0011] The supercharger 18 includes a turbine 18a and a compressor 18b. The turbine 18a and the compressor 18b are connected to each other. The turbine 18a is located upstream of the catalyst 28 in the exhaust passage 14. The compressor 18b is located downstream of the air flow meter 22 and upstream of the intercooler 25 in the intake passage 12. The turbine 18a and the compressor 18b are housed inside a housing (not shown).

[0012] A bypass passage 13 that bypasses the compressor 18b is connected to the intake passage 12, and a valve 11 is provided in the bypass passage 13. When the accelerator is OFF, air is bypassed from downstream to upstream of the compressor 18b through the bypass passage 13. A bypass passage 15 that bypasses the turbine 18a is connected to the exhaust passage 14, and a valve 16 is provided in the bypass passage 15.

[0013] A PCV (Positive Crankcase Ventilation) passage 23 is connected to the internal combustion engine 10 and a position upstream of the compressor 18b of the supercharger 18 in the intake passage 12. Blow-by gas is returned to the intake passage 12 through the PCV passage 23 and flows through the intake passage 12 together with air. Oil is mixed into the blow-by gas. Deposits are generated from the insoluble components contained in the oil and adhere to the compressor 18b. The efficiency of the supercharger 18 decreases due to the adhesion of deposits.

[0014] The intake air passes through the intake passage 12, is purified by the air cleaner 20, and is cooled by the intercooler 25. When the intake valve 30 opens, the intake air is introduced into the combustion chamber 27 of the internal combustion engine 10. The fuel injection valve 34 injects fuel into the combustion chamber 27. When an ignition plug (not shown) ignites, the air-fuel mixture burns in the combustion chamber 27. The piston 17 reciprocates up and down in the combustion chamber 27, and the driving force is transmitted to the crankshaft 19, causing the vehicle to travel.

[0015] When the exhaust valve 32 opens, the exhaust gas generated by combustion is discharged into the exhaust passage 14. The exhaust gas is purified by the catalyst 28 in the exhaust passage 14 and then discharged. The catalyst 28 is, for example, a three-way catalyst, which purifies carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), etc. in the exhaust gas.

[0016] When the exhaust gas is introduced into the turbine 18a of the supercharger 18, the turbine 18a rotates, and the compressor 18b connected to the turbine 18a also rotates. By the rotation of the compressor 18b, the intake air is supercharged, and the high-pressure intake air is sent into the combustion chamber 27 of the internal combustion engine 10 compared with the intake air on the upstream side of the compressor 18b.

[0017] The engine system 100 includes an air flow meter 22, a vehicle speed sensor 40, pressure sensors 42 and 43, and temperature sensors 44 and 46. The air flow meter 22 detects the flow rate of the intake air. The vehicle speed sensor 40 detects the speed (vehicle speed) of the vehicle on which the engine system 100 is mounted. The pressure sensor 42 detects the atmospheric pressure. The pressure sensor 43 detects the pressure of the air supercharged by the supercharger 18 (supercharging pressure). The temperature sensor 44 detects the temperature of the outside air. The temperature sensor 46 detects the temperature in the intake passage 12.

[0018] The ECU 50 is a control device for the internal combustion engine 10. The ECU 50 includes an arithmetic device such as a CPU (Central Processing Unit), and a storage device such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The ECU 50 performs various controls by executing programs stored in the ROM or the storage device.

[0019] The ECU 50 controls the opening degrees of the throttle valve 26, and the valves 11 and 16. The valve 11 is an air bypass valve (ABV), and can release the supercharged air by opening when the accelerator is off. The ECU 50 switches the on / off of fuel injection from the fuel injection valve 34 and controls the fuel injection amount. The ECU 50 acquires the intake air flow rate from the air flow meter 22 and the vehicle speed from the vehicle speed sensor 40. The ECU 50 acquires the atmospheric pressure from the pressure sensor 42 and the supercharging pressure from the pressure sensor 43. The ECU 50 acquires the outside air temperature from the temperature sensor 44 and the air temperature in the intake passage 12 from the temperature sensor 46.

[0020] The ECU 50 functions as a first acquisition unit that acquires the temperature of the air introduced into the compressor 18b of the supercharger 18, and a second acquisition unit that acquires the temperature of the housing of the compressor 18b.

[0021] When deposits accumulate on the compressor 18b of the supercharger 18, the efficiency of the compressor 18b decreases. The deposits are generated due to the insoluble components of the oil of the internal combustion engine 10. When the temperature of the compressor 18b rises, the oil is likely to evaporate. When the oil evaporates, the insoluble components contained in the oil are concentrated and hardened, and adhere to the compressor 18b as deposits. In order to predict the generation of deposits, it is effective to acquire the temperature of the housing of the compressor 18b.

[0022] FIG. 2 is a flowchart illustrating the processes executed by the ECU 50. The ECU 50 estimates the temperature T3 of the air introduced into the compressor 18b (step S10). Specifically, the temperature T3 is the temperature at the outlet portion of the compressor 18b (outlet temperature). The ECU 50 calculates the temperature T3 using, for example, the following equation (Equation 1). In Equation 1, P3 is the supercharging pressure, P1 is the pressure at the inlet of the compressor 18b, T1 is the intake air temperature, and η is the efficiency of the supercharger 18. The pressure P1 is estimated from the atmospheric pressure. The efficiency η is obtained, for example, from the pressure P1 and P3 and the intake air flow rate G in the intake passage 12. For example, a map associating the flow rate G, the pressures P1 and P3, and the efficiency η can be created through experiments or the like. The ECU 50 stores the map and obtains the efficiency η by referring to the map.

Equation

[0023] The ECU 50 performs a heat transfer analysis on the housing of the compressor 18b using the outlet temperature T3, the intake air flow rate G, the vehicle speed V, and the outside air temperature T0, and estimates the temperature T (member temperature) of the housing (step S12). In the heat transfer analysis, for example, the housing is assumed to be a plate-like substance. It is assumed that air at the temperature T3 introduced into the compressor 18b flows on one side of the housing. It is assumed that the running wind flows on the other side of the housing. Considering the heat capacity of the housing, the heat conduction in the housing is calculated to obtain the temperature T of the housing. This concludes the processing of FIG. 2.

[0024] According to the present embodiment, the ECU 50 obtains the temperature T3 of the air at the outlet of the compressor 18b and obtains the temperature T of the housing based on the temperature T3. The higher the temperature T, the more likely deposits are to be generated. By estimating the temperature T, the generation of deposits can be accurately predicted.

[0025] The ECU 50 acquires vehicle information (such as pressure P1, supercharging pressure P3, intake air temperature T1, flow rate G, vehicle speed, etc.) and estimates the temperature T of the housing. The temperature T in real time corresponding to each time point can be accurately estimated. Due to the heat capacity of the housing, the temperature T of the housing changes with a delay compared to the temperature T3 of the air. The ECU 50 estimates the temperature T through heat transfer analysis, taking into account the heat capacity and so on. Therefore, the accuracy of temperature estimation is improved. Since it is not necessary to provide a sensor for detecting the temperature of the housing, an increase in cost is suppressed.

[0026] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0027] 10 Internal combustion engine 11, 16 Valve 12 Intake passage 13, 15 Bypass passage 14 Exhaust passage 17 Piston 18 Supercharger 18a Turbine 18b Compressor 19 Crankshaft 20 Air cleaner 22 Airflow meter 23 PCV passage 25 Intercooler 26 Throttle valve 27 Combustion chamber 28 Catalyst 30 Intake valve 32 Exhaust valve 34 Fuel injection valve 40 Vehicle speed sensor 42, 43 Pressure sensor 44, 46 Temperature sensor 50 ECU 100 Engine system

Claims

【Claim 1】 A control device for an internal combustion engine equipped with a supercharger, wherein the supercharger is provided in an intake passage of the internal combustion engine and has a compressor, a first acquisition unit that acquires the temperature of the air at the outlet portion of the compressor based on the temperature of the air introduced into the intake passage, the pressure at the inlet of the compressor, and the boost pressure of the air boosted by the supercharger; a second acquisition unit that acquires the temperature of the housing of the compressor by performing a heat transfer analysis on the housing of the compressor using the temperature of the air at the outlet portion, the flow rate of the intake air in the intake passage, the speed of the vehicle on which the internal combustion engine is mounted, and the temperature of the outside air; and the second acquisition unit, in the heat transfer analysis, assumes that the housing of the compressor is a plate-like substance, air having the temperature at the outlet portion flows on one side of the housing, and running wind generated by the vehicle running flows on the other side of the housing, and calculates the heat conduction in the housing based on the heat capacity of the housing to acquire the temperature of the housing. A control device for an internal combustion engine.

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