METHOD FOR AUTHORIZING THE STARTING OF AN INTERNAL COMBUSTION ENGINE

Abstract

The invention relates to a method for authorizing the starting of a heat engine. This method comprises a step of measuring the air pump control value (E1); a step of measuring the valve control value (E2); a step of measuring the air pump rotational speed (E3); a step of measuring the valve position value (E4); and a step of starting the heat engine (E5) when the air pump control value is below a first threshold value, the valve control value is below a second threshold value, the air pump rotational speed is below a third threshold value, and the valve position value is below a fourth threshold value. Figure 1

Description

Title of the invention: METHOD FOR AUTHORIZING THE STARTING OF A HEAT ENGINE

[0001] The invention relates to the field of thermal engines, and more particularly to the polluting emissions emitted by these engines during start-up.

[0002] Known from the prior art is a patent application US2009025689 which describes a method for determining the volatility of the fuel during a cold start of an internal combustion engine of a motor vehicle. The objective of the invention is to minimize the quantity of fuel to be injected into said heat engine to start it when the outside temperatures are below 10 degrees Celsius. Indeed, when the outside temperature drops, the non-volatile parts of the fuel remain liquid and are evacuated by the exhaust system without having participated in the combustion. To compensate for this loss, it is necessary to enrich the fuel injection, that is to say to increase the quantity of fuel to be injected. However, this leads to overconsumption of fuel by the heat engine of said vehicle, and consequently, an increase in the quantity of polluting gases released into the environment by said vehicle.The first step in implementing said method is to determine an enrichment percentage based on a stored value representing the volatility of the fuel. The second step is to start the heat engine using the previously determined enrichment percentage. The third step consists in determining a predictive value for the starting quality, i.e. a fictitious value determined before starting. The fourth step is to determine a measured value for the starting quality when increasing the speed of the heat engine. The fifth step consists in determining a correction value for said stored value by comparing the measured value with the predictive value for the starting quality. In a sixth step, the stored value for the volatility is corrected by applying said correction value.Thus, in this way, only the amount of fuel necessary for the proper functioning of the heat engine is injected into said heat engine. In this way, said heat engine does not consume more than necessary and the emissions of polluting gases are reduced. However, a disadvantage remains. The volatile part of the fuel remains unchanged and, therefore, fuel consumption is always higher than it would be if all of the injected fuel were useful for combustion. Thus, the emissions of polluting gases are always higher than they should be.

[0003] The objective of the present invention is to remedy this drawback by proposing a process for authorizing the start of a thermal engine more quickly and without impacting the secondary air injection system, allowing the reduction of the emission rate of polluting gases.

[0004] To achieve this objective, the invention proposes a method for authorizing the start of a heat engine comprising a secondary air injection system, said secondary air injection system comprising an air pump and a valve, said heat engine comprising a means for measuring a control value of said air pump, a means for measuring a control value of said valve, a means for measuring a rotation speed value of the air pump, a means for measuring the position of the valve and a means for starting said heat engine, characterized in that said method comprises the following steps: - a step of measuring the air pump control value; - a step of measuring the valve control value; - a step of measuring the rotation speed value of the air pump; - a step of measuring the valve position value; - a step of starting said heat engine when, during a predetermined period of time, said air pump control value is less than a first threshold value, said valve control value is less than a second threshold value, said air pump rotation speed value is less than a third threshold value and said valve position value is less than a fourth threshold value.

[0005] Thanks to the invention, the starting of said vehicle is faster. In addition, starting is safer because it is ensured that the secondary air injection system is inactive.

[0006] Advantageously, during said step of starting said heat engine, the predetermined time period is less than 10 seconds.

[0007] Preferably, during said step of starting said heat engine, the predetermined time period is equal to 5 seconds.

[0008] Thus, the thermal engine can be started quickly.

[0009] Furthermore, the invention relates to a computer program comprising instructions which, when the program is executed by a computer, cause the latter to implement the steps of said method for authorizing the start of a thermal engine of a motor vehicle with a thermal engine as previously described.

[0010] Furthermore, the invention relates to a heat engine implementing the method for authorizing the start of a heat engine previously described.

[0011] Finally, the invention relates to a motor vehicle comprising a thermal engine mentioned above.

[0012] The invention will be further detailed by the description of an embodiment not limiting, and on the basis of the appended figure illustrating the invention, in which [Fig.l] schematically illustrates, in the form of a flowchart, a method for authorizing the start of a thermal engine.

[0013] [Fig.l] schematically illustrates, in the form of a flowchart, a method for starting a motor vehicle with a thermal engine. The thermal engine comprises a secondary air injection system. The secondary air injection system is a system for reducing pollutant gas emissions during cold starting of said thermal engine. The secondary air injection system comprises an air pump. The air pump of the secondary air injection system makes it possible to manage the ratio between air and fuel in said thermal engine. Furthermore, the secondary air injection system comprises a valve. The valve makes it possible to regulate the flow of air circulating in said secondary air injection system. The thermal engine comprises a means for measuring a control value of said air pump and a means for measuring a control value of said valve.The control value, whether assigned to the air pump or to the valve, corresponds to a unitless value determining the operating state of said air pump or said valve. For example, said valve control value is between 0 and 1, 0 being the minimum value for which the valve is completely closed and 1 being the maximum value for which the valve is completely open. Intermediate control values ​​of said valve are possible, for example for a value of 0.5 said valve is half-open, reducing by half the quantity of air that can pass through said valve compared to its capacity when the latter is completely open. In addition, the heat engine comprises a means for measuring a value of rotation speed of the air pump and a means for measuring the position of the valve.Concerning the position of the valve, the position value is a fictitious value assigned to the valve according to its position in said heat engine. In addition, said heat engine comprises a means for starting said heat engine. During a step of measuring the control value of the air pump E1, the control value of the air pump is measured in order to know the state in which it is, namely whether it is operating or not and at what intensity. The control value of the air pump is lower than a first threshold value. During a step of measuring the control value of the valve E2, the control value of the valve is measured in order to know its opening level as explained previously. The control value of the valve is lower than a second threshold value.In a step of measuring a rotational speed value of the air pump E3, the rotational speed value of the air pump is measured by said rotational speed sensor of said air pump. The rotational speed value of the air pump is less than a third threshold value. In a step . measuring the position value of the valve E4, the position of the valve is detected in said heat engine. A fictitious value is assigned to this data, corresponding to the position of said valve in said heat engine. The position value of the valve is less than a fourth threshold value. During a step of starting said heat engine E5', a non-activity of said secondary air injection system is verified. It is considered that the secondary air injection system is in a state of inactivity when said non-activity is detected when, during a predetermined period of time, said air pump control value is less than a first threshold value, said valve control value is less than a second threshold value, said air pump rotation speed value is less than a third threshold value and said valve position value is less than a fourth threshold value.Advantageously, said predetermined time period is less than 10 seconds, preferably the time period is equal to 5 seconds. When all of the previously mentioned conditions are met, the heat engine is then authorized to start. The emissions of polluting gases emanating from the start of said heat engine are then reduced. Furthermore, the invention relates to a computer program implementing said method. The invention also relates to a heat engine implementing the method for authorizing the start of a heat engine described above and a motor vehicle comprising such a heat engine.

Claims

Claims

1. Method for authorizing the start of a heat engine comprising a secondary air injection system, said secondary air injection system comprising an air pump and a valve, said heat engine comprising a means for measuring a control value of said air pump, a means for measuring a control value of said valve, a means for measuring a rotational speed value of the air pump, a means for measuring the position of the valve and a means for starting said heat engine, characterized in that said method comprises the following steps: - a step of measuring the control value of the air pump (El) - a step of measuring the control value of the valve (E2); - a step of measuring the rotational speed value of the air pump (E3); - a step of measuring the position value of the valve (E4);- a step of starting said heat engine (E5) when, during a predetermined period of time, said air pump control value is less than a first threshold value, said valve control value is less than a second threshold value, said air pump rotation speed value is less than a third threshold value and said valve position value is less than a fourth threshold value.;

2. Method according to claim 1 characterized in that, during said step of starting said heat engine (E5), the predetermined period of time is less than 10 seconds.

3. Method according to claim 2 characterized in that, during said step of starting said heat engine (E5), the predetermined time period is equal to 5 seconds.

4. Computer program comprising instructions which, when the program is executed by a computer, cause the latter to implement the steps of said method for authorizing the start of a motor vehicle with a thermal engine according to any one of claims 1 to 3.

5. Heat engine implementing the method for authorizing the start of a heat engine according to any one of claims 1 to 3.

6. Motor vehicle comprising a heat engine according to claim 5.

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