JP2015132241A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine degradation of a component in a fuel system due to influence of methanol included in fuel, and to enable a required measure to be taken.SOLUTION: A control device of an internal combustion engine: determines a value of a first parameter indicating a degree of fuel to degrade a component in a fuel system in accordance with a concentration of methanol in the fuel currently used; acquires the value of a second parameter indicating a frequency of operation or an operation period of the component in the fuel system; and calculates the value of a third parameter indicating a degradation level of the component in the fuel system on the basis of the values of the first parameter and the second parameter. The control device executes control to issue a warning or curb the degradation of the component in the fuel system when the value of the third parameter becomes larger than a predetermined value.

Description

  The present invention relates to a control device for an internal combustion engine using a fuel containing methanol.

  A fuel containing methanol may be used as a fuel for an internal combustion engine of an automobile. However, methanol has a lower viscosity than ethanol and has a high material aggression, so that it tends to cause deterioration of fuel system parts, specifically corrosion and wear. In particular, in a part where a high impact force acts, such as a valve portion of a fuel injection valve, a significant difference occurs in the degree of deterioration depending on the methanol concentration of the fuel. Therefore, in an internal combustion engine using a fuel containing methanol, it is desired to determine the deterioration of fuel system parts due to the influence of methanol contained in the fuel and take necessary measures.

  Patent Document 1 below discloses that the degree of deterioration of a component is estimated and the control of the internal combustion engine is made variable according to the degree of deterioration. However, the deterioration of fuel system parts due to the influence of methanol is not taken into consideration.

JP 2007-255307 A JP 2002-115591 A

Transactions of the Japan Society of Mechanical Engineers (C), Vol. 64, No. 618

  It is an object of the present invention to determine deterioration of fuel system parts due to the influence of methanol contained in fuel and to take necessary measures.

  In order to solve the above-mentioned problems, the present invention is currently using the value of the first parameter indicating the degree to which the fuel deteriorates the fuel system components in the control device for the internal combustion engine using the fuel containing methanol. Means for determining according to the methanol concentration of the fuel, means for obtaining a second parameter value indicating the number of operation times or operation time of the fuel system component, the value of the first parameter and the value of the second parameter A means for calculating a value of a third parameter indicating the degree of deterioration of the fuel system component based on the value, and a warning is issued when the value of the third parameter exceeds a predetermined value, or And a means for executing control for suppressing deterioration of the fuel system component.

  According to the present invention, the degree of deterioration of fuel system parts due to the influence of methanol contained in fuel can be quantitatively evaluated, and necessary measures based on the quantitative evaluation, that is, issuing warnings or The control which suppresses deterioration of fuel system parts can be performed.

It is a figure for demonstrating the method to judge the degree of deterioration of the fuel injection valve by the fuel containing methanol. It is a figure for demonstrating the method of preventing the fall of the vehicle life by deterioration of a fuel injection valve.

  The control apparatus according to the embodiment of the present invention is applied to an internal combustion engine that can use fuel containing methanol, specifically, methanol-mixed gasoline. Although the methanol concentration of commercially available methanol-mixed gasoline is not necessarily constant, the methanol concentration of the fuel used can be directly measured by a methanol concentration sensor provided in the fuel system, or an air-fuel ratio sensor provided in the exhaust system It can also be estimated from the output of. Each time fueling is performed, the control device measures or estimates the methanol concentration of the fuel that is currently used, and stores it in the memory.

  The control device has a function of determining deterioration of the fuel injection valve and taking necessary measures. The deterioration of the fuel injection valve proceeds by the collision between the needle of the valve portion and the seat each time the fuel injection valve is operated. The fuel serves as a cushion to reduce the impact caused by the collision between the needle and the seat. However, methanol contained in the fuel used in the internal combustion engine of the present embodiment has a low viscosity and does not have an impact relaxation force like other polymer fuels. Therefore, the wear of the valve portion of the fuel injection valve increases according to the methanol concentration of the fuel and according to the number of operations of the fuel injection valve. Therefore, the control device quantitatively determines the degree of deterioration of the fuel injection valve based on the methanol concentration of the fuel used and the number of operations of the fuel injection valve.

  Hereinafter, a method for determining the degree of deterioration of the fuel injection valve caused by the fuel containing methanol will be described with reference to FIG. The horizontal axis of the chart of FIG. 1 is the operation time, and the vertical axis is the methanol concentration of the fuel used, the component deterioration degree determined from the methanol concentration, the number of component operations, and the integrated deterioration degree.

  The methanol concentration of the fuel used may be a measured value or an estimated value. Every time refueling is performed, the value of the methanol concentration stored in the memory is updated, and the value is held until the next refueling.

  The degree of component deterioration is a parameter indicating the degree to which the fuel deteriorates the fuel injection valve, and the value is determined by the methanol concentration of the fuel used with reference to a table prepared in advance. The higher the methanol concentration of the fuel used, the greater the component deterioration level. Each time the methanol concentration value stored in the memory is updated, the component deterioration degree value is also updated, and the value is held until the next methanol concentration value update.

  The number of times of component operation is the number of operations of the fuel injection valve, that is, the number of collisions between the needle of the valve portion and the seat. The control device continuously counts the number of operations from the initial state of the fuel injection valve, and updates the value stored in the memory each time the operation is performed.

  The integrated deterioration level is expressed as a value obtained by integrating the component deterioration level, which is the first parameter, with the number of component operations, which is the second parameter. The integrated deterioration degree is a parameter indicating the deterioration degree of the fuel injection valve. It can be read from the change in the value of the integrated deterioration degree that the more frequently the fuel having a high methanol concentration is used, the faster the deterioration proceeds with respect to the number of operations. The control device calculates the integrated deterioration degree as the third parameter every time the number of component operations is incremented, and updates the value stored in the memory.

  The degree of deterioration of the fuel injection valve can be determined quantitatively from the value of the integrated deterioration degree. An upper limit value is determined in advance for the integrated deterioration degree. This is the value indicated by the deterioration limit determination value in the chart of FIG. 1, and corresponds to a value that is estimated to have deteriorated to a limit that the fuel injection valve can withstand. The control device takes necessary measures when the integrated deterioration degree becomes larger than the deterioration limit judgment value. The necessary measures include issuing a warning to the user by a method such as turning on a warning lamp on the instrument panel, and executing control to reduce the impact of the valve portion and suppress deterioration of the fuel injection valve. included. Specific examples of control include reducing the operating speed of the fuel injection valve and lowering the fuel temperature. Moreover, you may make it perform correction | amendment control for compensating the fall of the engine performance by deterioration of a fuel injection valve as needed.

  Next, a method for preventing a decrease in vehicle life due to deterioration of the fuel injection valve will be described with reference to FIG. The horizontal axis of the chart of FIG. 2 is the driving distance of the vehicle, and the vertical axis is the above-described integrated deterioration degree.

  The function deterioration prediction line shown in the chart of FIG. 2 shows the change in the integrated deterioration degree predicted from the increasing rate of the integrated deterioration degree with respect to the current driving distance. A vehicle life standard corresponding to the designed vehicle life is set for the driving distance. The control device predicts the value of the integrated deterioration degree at the time when the driving distance reaches the vehicle life standard from the increasing rate of the integrated deterioration degree with respect to the driving distance. Then, when it is predicted that the cumulative deterioration level at the time when the driving distance reaches the vehicle life criterion exceeds the deterioration limit determination value, the control device notifies the user. The announcement includes recommending the use of fuels with low methanol concentrations. The notification method includes displaying the notification content on the information display and lighting the instrument panel lamp. By refraining from using fuel with a high methanol concentration, the user can suppress deterioration of the fuel injection valve and prevent the vehicle life from becoming shorter than the reference life.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the operation time of the fuel injection valve may be used as the second parameter instead of the number of operations of the fuel injection valve. Further, the vehicle life may be determined by driving time instead of the driving distance of the vehicle. Further, the fuel system parts that are subject to determination of the degree of deterioration include not only fuel injection valves but also fuel pumps and regulators.

Claims (1)

In a control device for an internal combustion engine using a fuel containing methanol,
Means for determining a value of a first parameter indicating the degree to which the fuel degrades the fuel system parts according to the methanol concentration of the fuel currently used;
Means for obtaining a value of a second parameter indicating the number of operations or operation time of the fuel system component;
Means for calculating a value of a third parameter indicating the degree of deterioration of the fuel system component based on the value of the first parameter and the value of the second parameter;
Means for issuing a warning when the value of the third parameter is larger than a predetermined value, or executing control for suppressing deterioration of the fuel system component;
A control device for an internal combustion engine, comprising:

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