Vehicle control device

Abstract

To prevent freezing of a throttle valve while reducing electric power consumption of an on-vehicle battery.SOLUTION: A vehicle control device 1 that opens / closes a throttle valve 2 includes: a determination section (S1) that determines whether or not an outside air temperature is lower than a freezing temperature of the throttle valve 2; a calculation section (S2-S5) that calculates a blow-by gas blowing back amount, a moisture amount in the blow-by gas, a moisture amount in suction air and a temperature of the throttle valve 2 when the determination section makes an affirmative determination; and an estimation section (S6, S7) that estimates a moisture amount adhering to the throttle valve 2 during traveling of a vehicle on the basis of a calculation result from the calculation section.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] For example, Patent Document 1 states that "by driving the throttle valve to open and close during the period when the ice on the throttle valve has melted after the engine has stopped, water droplets accumulated on the surface and bottom end of the throttle valve are removed, and adhesion welding control is performed to prevent the throttle valve from freezing." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-89538 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned Patent Document 1, the throttle valve is opened and closed every time the engine is stopped, which raises concerns about increased power consumption from the vehicle battery.

[0005] In view of the above circumstances, an object of the present invention is to provide a vehicle control device that can prevent the throttle valve from freezing while reducing the power consumption of the vehicle battery. [Means for solving the problem]

[0006] The present invention is characterized in that a vehicle control device that drives a throttle valve to open and close includes a judgment unit that judges whether the outside air temperature is lower than the freezing temperature of the throttle valve, a calculation unit that calculates the amount of blow-by gas blown back, the amount of moisture in the blow-by gas, the amount of moisture in the intake air, and the temperature of the throttle valve when the judgment unit makes a positive judgment, and an estimation unit that estimates the amount of moisture adhering to the throttle valve while the vehicle is running based on the calculation results of the calculation unit.

[0007] According to this configuration, when the outside air temperature is lower than the freezing temperature of the throttle valve, the amount of moisture adhering to the throttle valve while the vehicle is running is estimated, so that it is possible to drive the throttle valve to open and close for the time required to blow off the estimated amount of moisture from the throttle valve, for example, before the conditions for freezing of the moisture adhering to the throttle valve are met.

[0008] This reduces the number of times the process of blowing off moisture from the throttle valve needs to be performed, compared to the conventional case in which the throttle valve is opened and closed each time the engine is stopped, thereby reducing the power consumption of the vehicle battery. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a vehicle control device that can prevent the throttle valve from freezing while reducing the power consumption of the vehicle battery. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing the configuration of an embodiment of a vehicle control device according to the present invention; [Figure 2] 4 is a flowchart illustrating the operation of the vehicle control device. [Figure 3] Graph (a) shows the relationship between engine speed and blow-by gas, and graph (b) shows the relationship between engine load or Pmax and blow-by gas. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0012] An embodiment of the present invention is shown in Figures 1 to 3. At least a throttle control device 3 for driving a throttle valve 2 to open and close, and an input device 4 are connected to a vehicle control device 1 of this embodiment.

[0013] The vehicle control device 1 is made up of an ECU (Electronic Control Unit), and the ECU includes a CPU, a ROM, a RAM (also called a memory), a communication I / F, and an input / output I / F that are communicably connected to each other via a bus.

[0014] This vehicle control device 1 performs at least various calculation processes for controlling the operation of an engine (not shown), a process of acquiring various data sent from an input device 4 and storing it in memory, a process of driving the throttle valve 2 to open and close, a process of estimating the amount of moisture adhering to the throttle valve 2 based on the data stored in the memory, and a process of blowing off the moisture adhering to the throttle valve 2.

[0015] The throttle valve 2 is installed in an intake pipe of an engine mounted on a vehicle (not shown), and is driven by a throttle control device 3.

[0016] The throttle control device 3 includes a throttle motor 31 and a motor driver 32. The throttle motor 31 drives the throttle valve 2 to open and close. The motor driver 32 controls the throttle motor 31 in response to a command from the vehicle control device 1.

[0017] The input device 4 has sensors for detecting the state quantities of each part of the engine, and the detected data is transmitted to the vehicle control device 1 via a CAN (Controller Area Network) communication system installed in the vehicle and stored in the memory (not shown) of the vehicle control device 1.

[0018] Examples of the sensors include an air supply amount sensor 11, a fuel injection amount sensor 12, an air-fuel ratio sensor 13, an engine rotation speed sensor 14, a throttle opening sensor 15, an intake air temperature sensor 16, an intake pipe negative pressure sensor 17, a humidity sensor 18, an oil temperature sensor 19, a crankcase internal pressure sensor 20, and an outside air temperature sensor 21.

[0019] The air supply amount sensor 11 detects the amount of air supplied to the engine. The fuel injection amount sensor 12 detects the fuel injected into the engine by the injector. The air-fuel ratio sensor 13 is an A / F sensor or O2 sensor installed in the exhaust system. The engine speed sensor 14 detects the rotation speed of the crankshaft. The throttle opening sensor 15 detects the opening of the throttle valve 2. The intake air temperature sensor 16 detects the temperature of the intake air taken into the engine. The intake pipe negative pressure sensor 17 detects the negative pressure generated in the intake pipe connected to the engine. The humidity sensor 18 detects the humidity outside the vehicle. The oil temperature sensor 19 detects the temperature of the engine oil in the crankcase. The crankcase internal pressure sensor 20 detects the pressure inside the crankcase. The outside air temperature sensor 21 detects the temperature outside the vehicle.

[0020] Next, the operation of the vehicle control device 1 will be described with reference to FIGS.

[0021] The flowchart shown in FIG. 2 starts when an ignition switch (not shown) of a vehicle is turned on, and steps S1 to S7 are repeated until the ignition switch is turned off.

[0022] In step S1, it is determined whether the detected value (outside air temperature) input from the outside air temperature sensor 21 is less than a predetermined threshold value α. The threshold value α is set to the temperature at which the throttle valve 2 freezes (referred to as the freezing temperature).

[0023] If the determination in step S1 is negative, the flow chart is terminated, whereas if the determination is positive, the state quantities of the various parts of the engine are detected in steps S2 to S5.

[0024] In step S2, the amount of blow-by gas blown back while the vehicle is running is calculated. This amount of blow-by gas blown back is obtained from a map value that indicates the correlation between the engine speed, engine load, maximum cylinder pressure (Pmax), and engine ignition timing and the amount of blow-by gas generated, and a map value that indicates the correlation between any one of the intake manifold negative pressure, throttle opening, and load and the amount of blow-by gas blown back relative to the crankcase pressure value.

[0025] Although not shown, Pmax may be a detected value from a cylinder pressure sensor, or may be a value calculated from a map showing the correlation between the intake manifold negative pressure, throttle opening, engine load, and cylinder pressure. The amount of blow-by gas generated is less sensitive to changes in engine speed as shown in Figure 3(a), but is more sensitive to changes in load or Pmax as shown in Figure 3(b). Blow-by gas is recirculated to the intake system using the differential pressure between the crankcase pressure and the intake manifold negative pressure. Therefore, the greater the intake manifold negative pressure, the greater the flow rate of the blow-back gas. It is preferable to consider the flow characteristics of the PCV valve (not shown) when determining the final flow rate.

[0026] In step S3, the amount of moisture in the blow-by gas is calculated. This amount of moisture in the blow-by gas is obtained from a map value that shows the correlation between the amount of moisture in the blow-by gas and the ambient temperature, fuel injection amount (or air-fuel ratio), fuel type, oil temperature, and water temperature. Note that the moisture that forms ice comes from the moisture contained in the air and the fuel, so the type of fuel (e.g., E30 (a well-known fuel, specified by the ratio of ethanol mixed into gasoline)) and the increase in the amount from the stoichiometric air-fuel ratio are referenced. In addition, the oil and water temperatures are referenced to determine the amount of unburned fuel and the amount of fuel adhering to the combustion chamber walls. In other words, the fuel does not contribute to the amount of moisture in the blow-by gas until the low oil temperature range (the temperature at which the moisture in the fuel dissolves in the engine oil in the crankcase).

[0027] In step S4, the amount of moisture in the intake air is calculated from a map value that indicates the correlation between the intake air temperature and humidity and the amount of moisture in the intake air.

[0028] In step S5, the temperature of the throttle valve 2 is calculated. This temperature of the throttle valve 2 is obtained from a map value that shows the correlation between the temperature of the throttle valve 2 and the vehicle speed, gear (or engine speed), engine load, intake air temperature, and driving time. In cooling the throttle valve 2, the amount of heat transfer is generally proportional to the temperature difference between two objects, the area, and the heat transfer coefficient. Since the heat transfer coefficient increases as the flow velocity of the air passing through the throttle valve 2 increases, the engine speed and engine load, which are highly correlated with the flow velocity of the air passing through the throttle valve 2 while the vehicle is running, are referenced.

[0029] Thereafter, in step S6, the amount of ice adhering to the throttle valve 2 per unit time is calculated, and in step S7, the amount of water adhering to the throttle valve 2 during driving is estimated, and the process returns to the main routine (not shown).

[0030] The amount of ice adhering is obtained from a map value that shows the correlation between predetermined conditions (including the calculated value of the amount of moisture in the blow-by gas, the calculated value of the amount of moisture in the intake air, and the calculated value of the temperature of the throttle valve 2) and the amount of ice adhering per unit time. The amount of moisture in the air, the flow velocity of the intake air, the air temperature, and the amount of ice adhering when the temperature of the throttle valve 2 is maintained for a predetermined time are obtained by experiment in advance, and a map showing the correlation between them is created. The amount of moisture adhering to the throttle valve 2 is estimated by integrating the calculated value of the amount of ice adhering and the operating time.

[0031] In the flowchart of Figure 2, step S1 corresponds to the determination unit described in the claims, steps S2 to S5 correspond to the calculation unit described in the claims, and steps S6 and S7 correspond to the estimation unit described in the claims.

[0032] As described above, according to the embodiment to which the present invention is applied, when the outside air temperature is lower than the freezing point of the throttle valve 2, the amount of moisture adhering to the throttle valve 2 while the vehicle is running is estimated. Therefore, it becomes possible to drive the throttle valve 2 to open and close for the time required to blow off the estimated amount of moisture from the throttle valve 2, for example, before the conditions for freezing of the moisture adhering to the throttle valve 2 are met.

[0033] This reduces the number of times that the process of blowing off moisture adhering to the throttle valve 2 is performed, compared to the conventional case in which the throttle valve 2 is opened and closed each time the engine is stopped, and as a result, it becomes possible to reduce the power consumption of the vehicle battery (not shown).

[0034] The present invention is not limited to the above-described embodiments, but can be modified as appropriate within the scope of the claims and the equivalents thereof.

[0035] For example, in the above embodiment, it is possible to omit step S1 shown in Fig. 2. Even in this case, it is possible to reduce the power consumption of the vehicle battery by driving the throttle valve 2 to open and close for a time required to blow off the amount of water estimated in step S7 of Fig. 2 from the throttle valve 2, for example, before the conditions for freezing of the water adhering to the throttle valve 2 are met. [Industrial Applicability]

[0036] The present invention can be suitably used in a vehicle control device. [Explanation of symbols]

[0037] 1 Vehicle control device 2 throttle valve 3 Throttle control device 31 Throttle motor 32 Motor driver 4 Input Devices 11 Air supply sensor 12 Fuel injection amount sensor 13 Air-fuel ratio sensor 14 Engine RPM Sensor 15 Throttle opening sensor 16 Intake air temperature sensor 17 Intake pipe negative pressure sensor 18 Humidity Sensor 19 Oil temperature sensor 20 Crankcase pressure sensor 21 Outside air temperature sensor

Claims

[Claim 1] In a vehicle control device that drives a throttle valve to open and close, a determination unit that determines whether the outside air temperature is lower than the freezing temperature of the throttle valve; a calculation unit that calculates the amount of blow-by gas blown back, the amount of moisture in the blow-by gas, the amount of moisture in the intake air, and the temperature of the throttle valve when the determination unit makes a positive determination; an estimation unit that estimates an amount of moisture adhering to the throttle valve while the vehicle is running based on a calculation result of the calculation unit.

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