WO2007080347A1

WO2007080347A1 - Method of protecting the ventilating means of an internal combustion engine

Info

Publication number: WO2007080347A1
Application number: PCT/FR2007/050625
Authority: WO
Inventors: Jean-Charles Pichon
Original assignee: Peugeot Citroën Automobiles Sa.
Priority date: 2006-01-10
Filing date: 2007-01-08
Publication date: 2007-07-19
Also published as: FR2896013A1; EP1971758A1; DE602007008053D1; EP1971758B1; FR2896013B1; ATE475796T1

Abstract

The invention relates to a method of protecting the ventilating means (10) of a vehicle internal combustion engine (20, 22) against blocking. The method consists in operating the ventilating means periodically (48) when the climatic conditions (54, 58) indicate that the ventilating means are at risk of blocking, the operating modalities of said means comprising the duration and the frequency Tc of each operating period and being determined as a function of at least one parameter. The invention applies most particularly to the automotive industry.

Description

METHOD FOR PROTECTING THE VENTILATION MEANS OF AN INTERNAL COMBUSTION ENGINE

The present invention claims the priority of the French application 0650094 filed on January 10, 2006, the entire contents of which are incorporated herein by reference.

The present invention relates to a method for protecting the ventilation means of an internal combustion engine of a vehicle against the blockage of these means due to climatic conditions.

The internal combustion engines are equipped with ventilation means (designated "motorcycle ventilation group", GMV abbreviated) that sucks in or blows air from outside the vehicle to cool the engine via the heat transport circuit. These means mainly comprise one or more fans powered by one or more electric motors or with a belt connected to the motor shaft (crankshaft) and an electromechanical engagement type. Fans are only turned on when the engine temperature reaches or exceeds a predetermined value.

In very cold weather, frost or snow may block the ventilation unit, whether it is of the blower type (the fan is located in front of the radiator in which the coolant circulates) or of the suction type (the fan being located behind the fan). radiator). The fan can be blocked by a direct accumulation of snow on the fan when the vehicle is running or by frozen water. Snow can melt when driving under the hood when the engine is running, then freeze. This can happen when the vehicle is moving, but also after the engine has stopped, if the outside temperature is low enough. Blocking the group ventilation can cause significant damage to the engine, but also to the automatic gearbox when the vehicle is equipped. Indeed, the blocking of the ventilation unit prevents efficient cooling of the engine and the gearbox, especially when the vehicle is driving in town where the converter of the automatic transmission generates a lot of calories. Blocking the fan can also cause an electrical failure.

To limit the entry of snow through the vehicle's grille, it is possible to place a screen to reduce the air intake area. However, the air intake can not be completely obstructed and therefore snow can accumulate at the entrance to the engine compartment. In addition, the setting up of a screen is a manual operation that must be done in time and we must not forget to remove the screen at the end of winter under penalty of overheating of the engine. The present invention provides a solution that reduces the risk of blocking the motorcycle fan unit due to snow and ice formation.

More specifically, the invention relates to a method of protection against the blockage of the ventilation means of an internal combustion engine of a vehicle, consisting in operating the ventilation means periodically when the weather conditions indicate a risk. blocking the ventilation means, the operating modes of said means comprising the duration and the frequency of each operating period and being determined according to at least one parameter.

Advantageously, said operating modes also comprise the speed of rotation of the ventilation means. Said operating modes can be adjusted according to at least one of the following parameters: the temperature external to the vehicle, the average speed of the vehicle, the average fuel consumption of the vehicle, the state of the vehicle windscreen wiper on or off and the driving profile of the vehicle corresponding to the city traffic, road traffic or stationary vehicle.

According to a preferred embodiment, a test is performed to determine the operating state of the ventilation means.

This test may consist in starting the ventilation means and, following the start of said means, determining the appearance of at least one characteristic event of the blocking of these means.

According to a possible embodiment, a relatively stable operating speed of the engine is detected and the ventilation means are only switched on if such a steady state is detected. The occurrence of at least one of the following events characteristic of the blocking of the ventilation means is then detected: overcurrent of the electric current actuating the ventilation means, reduction of the rotational speed of the internal combustion engine and increase of the consumption in fuel of said engine.

Advantageously, when a blockage is detected, one places oneself in the operating conditions at full speed of the ventilation means in order to try to unblock them. A new blocking test may be carried out immediately after the attempt to operate at full speed and, if a blockage is detected again, a new attempt to operate at full speed is performed, the blocking test operations and unlocking attempt being performed until unblocking of the ventilation means. If the ventilation means remain blocked after a predetermined number of unsuccessful unlocking attempts, the Lock test and unlock attempt attempts stop and an alarm indicates to the driver of the vehicle that the vehicle is malfunctioning.

The test to determine the possible blockage of the ventilation means may be systematically performed before the operation of said means for short periods.

Other advantages and features of the invention will become apparent from the following description of an embodiment of the invention, given by way of non-limiting example, with reference to the accompanying drawings and in which:

- Figure 1 shows schematically a motorcycle fan assembly with its engine environment and various components; and

- Figures 2 to 4 are diagrams illustrating an embodiment of the invention. In Figure 1, the ventilation means 10 are constituted by a motorcycle fan assembly mainly comprising a fan 12 actuated by an electric motor, whose start and stop are controlled by means of a service housing 14 Air 16 is sucked outside the vehicle by the fan 12. This air passes through a radiator 18 in which circulates a heat transfer fluid. The latter is intended to cool an internal combustion engine 20 which is coupled to a manual or automatic gearbox 22. A pump 24 circulates the heat transfer liquid in a cooling circuit, the circulation of the cooled fluid being represented by broken lines. and that of the hot fluid being represented by dotted lines. The hot heat transfer fluid leaves the engine block by an output housing 26 equipped with a thermostat. The latter directs the coolant in closed circuit, to the pump 24, if the temperature of the engine is low. If this temperature is higher at a predetermined temperature, the thermostat directs the heat transfer fluid to the radiator 18 and to the heating system 28 of the passenger compartment. The coolant recovers calories from the hot elements (the engine 20 possibly equipped with a turbocharger and the gearbox 22) to evacuate through the radiator 18 and the heating system 28 of the passenger compartment. A temperature probe 30 attached to the radiator 18 measures the temperature of the coolant. This probe is connected to a motor control unit 32. When the temperature reaches a predetermined threshold (set between approximately 83 and 100 ^° C.), the control unit 32 sends a control signal to the service box 14 in order to implement run the fan 12 and operate it at a rotation speed which depends on the temperature of the coolant. When the temperature falls below this threshold, the control unit orders the fan to stop.

In order to implement the method of the present invention, the vehicle comprises a service housing 34 for acquiring data relating to at least one of the following parameters: the outside temperature 36, the speed 38 of the vehicle, the operation windscreen wiper 40 (if the windscreen wiper is on or off) and possibly other information 42 such as the vehicle running profile (city or highway traffic, vehicle on the road). stopping) or fuel consumption. The speed and the fuel consumption can be averages calculated over appropriate distances which can for example be between 100 meters and several kilometers or over the last period of elapsed time which can be for example of the order of several minutes.

According to the invention, the fan 12 of the fan motor unit 10 is actuated intermittently and for short periods which can be for example from a few seconds to a few minutes. The operating modes of the motorcycle fan unit, mainly the duration and the frequency of each operating cycle, are controlled according to one or more predefined parameters among which may be mentioned the temperature outside the vehicle, the operation of the wiper. front window (in the on or off position), the driving profile (vehicle stationary or driving on the road or motorway or in the city), the average speed over the last kilometers traveled or over a period of time (rolling data) and the average consumption also over the last kilometers or over a period of time (also a slippery data).

Figures 2 to 4 illustrate the diagram of a form of implementation of the invention. For this particular form of implementation, four modes of operation can be distinguished: a first mode 44 for activating the method, followed by a mode 46 for detecting a possible blockage of the motorcycle fan unit (FIG. 2), followed by a protection mode 48 (Figure 3), itself followed by a protection mode with stopping the engine of the vehicle 50 (Figure 4). For a simplified implementation of the invention, one can be satisfied with the protection mode 48 (FIG. 3) only.

By the activation mode 44 (Figure 2), it is determined whether or not the fan motor unit needs to be protected. The internal combustion engine of the vehicle is started (52) and a logic 54 determines whether the vehicle has been sold in a geographical area where there is a risk of snow or frost. Alternatively, the geographical area of use of the vehicle can be obtained by an onboard system of the GPS ("Global Positioning System") type. If there is no risk, the process is not implemented (56). If a risk exists, we compare the outside temperature Text with a threshold of predetermined temperature Tmin (58) for which and below which a risk of snow or frost exists (for example temperature <2 ° C). If the vehicle is equipped with an automatic gearbox, it is decided that the risk exists if the gearbox is set to "snow" mode. If the risk does not exist, the process is not activated (56). If the risk exists, a counter N of periodic fan triggers is reset, as well as a counter of the number b of fan locks (60), and then blocking detection mode 46 is set to determine the operating state of the fan motor unit (blocked or not). This blocking detection mode is advantageously carried out at the start of the vehicle and then periodically.

A counter of the number n of tests (ntest) for blocking the fan is first reset (62). Waiting for a maximum time (Tl = Tmax) stable operating conditions of the engine (64). This may be idle operation, just after start-up, with no action that can interfere with idle stability (eg, starting a windshield wiper, power window, or de-icing). the rear window or the actuation of the power steering). If a steady state is not obtained after a waiting time T greater than the time T1 (the time T1 being chosen to the maximum of the order of one minute), it goes directly to the protection mode 48 (FIG. 3) without performing a blocking test. In the opposite case, the counter of the number n of blocking tests is incremented by one unit at n + 1 (66). The blocking test is then performed (68). For this, a brief rotation of the fan motor unit at medium speed is ordered (68), for example for 3 seconds. This time must be short enough not to produce electrical problems if the fan is blocked. In general, a few seconds are sufficient to perform the test. If a control system of the intensity of the electric current at the terminals of the motorcycle fan unit equips the vehicle, it detects a current overcurrent due to a blocking of the motorcycle fan unit. In the absence of such a system, one can look at the consequence of such overcurrent on the engine idle. When rotating the fan, a peak of electric current occurs which causes the engine speed to drop briefly. This is observed engine idling. In the event of a blockage of the fan, the overcurrent peak is larger and longer, which modifies the idle speed of the motor more significantly and longer. The amount of fuel injected is also increased by the engine control unit to regain the desired idle. Each of these parameters can therefore provide an indication of the operating state (blocked or not) of the fan motor unit. It is examined whether the current overcurrent and / or the engine idle decrease and / or the fuel consumption increase is less than a predetermined value (70). If this is the case, there is no blocking of the fan, the numbers N and b are equal to zero and the protection mode (48, figure 3) is entered. If the current overcurrent and / or the engine idle decrease and / or the fuel consumption increase is greater than a predetermined value (70), there is blockage of the fan and the counter indicating the blocking number b is incremented by one unit at b + 1 (72). The number b of blockages is then compared to a predetermined maximum number bmax of blockages. If b is less than bmax, an unlocking attempt is made (74) under the operating conditions of the fan at full speed for a predetermined period of time (for example a few seconds). A new blocking test is then performed (64, 66, 68, 70). This test operation of locking and unlocking attempt is repeated until the unlocking of the fan or until b is equal to bmax. In this case, it is decided that too many blockages have occurred, an alarm (76) signals to the driver a malfunction of the vehicle or, more precisely, a failure of the cooling circuit or the motorcycle fan unit, and the unlocking attempt is abandoned, since the fan protection mode is not engaged (78).

If the fan is not blocked, it goes to the protection mode 48 (Figure 3) to reduce or even eliminate the risk of blocking the motorcycle fan unit by snow or frost. The counter of the number N of periodic trips is incremented to N + 1 (step 80). A brief rotation of the fan is periodically ordered. A few seconds of operation are usually sufficient to prevent the fan from blocking. In addition, this operating time should be short enough not to cause electrical problems in case the fan is blocked. The capacity of the battery fitted to the vehicle must also be taken into account. A short duration also makes it possible not to generate a noise harmful to the comfort of the passengers. The operating modes of the fan for these periodic trips depend on one or more parameters. By operating modes is meant the duration and the frequency of the cycles of the short operations and, advantageously but not necessarily, the speed of rotation of the fan. As parameters, it is possible, for example, to take into account the driving profile (82), that is to say, road or highway driving or city driving, and the average speed V (84) during for example the last one hundred meters or the last kilometer traveled (s) or the last period of elapsed time, for example the minute preceding the start of the fan (if V is less than for example three predetermined thresholds Vl, V2 and V3). We obtain an uncorrected time Tnc between two trips (86) which may take the value T1, T2 or T3. The time Tnc is then adjusted taking into account two parameters: the position of the front windscreen wiper switch (88) and the outside temperature (90). For these two parameters, a multiplicative factor M1 and M2 are respectively determined. If the wiper switch is off, Ml = I, if it is on "intermittent" Ml = ml and if it is on "continuous" Ml = m2. If the outside temperature is lower than tmin1, tmin2 and tmin3 (with tm3 <tm2 <tml), M2 is equal to 1, ml and m2 respectively (and equal to 1 if the temperature is greater than tml). The corrected time Tc between two successive triggers (92) is then determined by the formula Tc = Tnc x Ml x M2.

Other data can also be taken into account in order to better understand the real situation in which the vehicle is located. For example, the position of the gearbox lever in the "snow" position and the average fuel consumption can give an indication of this situation. In addition, if the temperature of the coolant is high enough, the risk of blockage of the fan is very small and it is desirable not to operate in protection mode so as not to unnecessarily alarm the driver and not to consume the battery. energy unnecessarily.

The fan motor unit is then turned on at the end of the time Tc for a short period (for example a few seconds, but this time may be longer if necessary) and at an average rotation speed (94). Then we wait (96) for a time Tc and look (98) if the number N of periodic trips is less than a predetermined maximum number Nrot max. If N <Nrot max, we look (100) if a blocking test could not be carried out (in this case the number n of blocking tests is equal to zero) or if a blocking of the fan is in progress (in this case the blocking number b is different from zero). If the blocking test could be performed (ntest different from zero) or if the fan is not blocked (b = 0), the fan operation is normal. The operations of the protection mode (48) are then restarted by repositioning on the diagram in step 80 (at the top of FIG. 3). If the number N of periodic trips is equal to Nrotmax, then a blocking test is again carried out by returning to step 64 of FIG.

If step 100 of the method indicates that the blocking test could not be carried out (ntest = 0) at the beginning of the engine start-up or in periodic verification or when a blockage is in progress (b different from zero), the blocking test is repeated by repositioning at step 62 of FIG. 2.

Figure 4 illustrates in diagrammatic form a method of tripping the fan while the vehicle engine has been stopped (102). After stopping the engine, the accumulated snow melts near the hot parts, the water runs and can freeze. The accumulation of ice can then block the motorcycle fan unit. To avoid this problem, the motorcycle fan unit is advantageously started repeatedly over a period determined after stopping the engine of the vehicle.

A counter indicating the number Npost of periodic trips made after the engine has been stopped is reset (104). The counter is then incremented to Npost + 1 (step 106) and it is examined whether the number Npost is less than a predetermined maximum number Npost-max (108). If so, wait for a predetermined period of time Tpost (110) then the fan is turned on (112) for a few seconds or minutes at an average rotational speed. Then return to the start step 106 to continue the cycle of periodic triggers, and so on, until the number Npost is equal to Npost-max. We then stop the triggering process of the fan (114), having judged that after a Npost-max number of trips of the fan after stopping the motor the risk of blocking the fan is negligible.

It may be possible, in a dashed mode of operation (120), to detect a blockage of the fan (116) by monitoring the occurrence of an abnormally high electrical overcurrent when the fan is cycled (step 112). ) after stopping the engine. If such an overcurrent does not occur, so if the fan is not blocked, it returns to step 106 to continue the cycle of periodic fan trips. On the other hand, if an overcurrent occurs, the fan is powered to run at high speed to try to unblock it (118). If successful, the periodic triggers process resumes at step 106. In the event of failure, the process stops. An alarm can indicate to the driver the malfunction of the vehicle, or more precisely of the cooling circuit, at the next start. Since a lock test will be performed again at the next engine start if the outside temperature warrants it, we can choose not to alert the driver, since this new test may indicate that the fan is no longer blocked (in case warming of the outside temperature for example).

Embodiments other than that described and shown may be devised by those skilled in the art without departing from the scope of the present invention. These embodiments may differ from that previously described depending in particular on the desired level of "security". For example, it has been reported that the fan is periodically turned on for short periods of a few seconds. These periods can of course be longer, of the order of a minute for example, if the outside temperature is very low.

Claims

1. A method of protecting against the blocking of the ventilation means (10) of an internal combustion engine (20, 22) of a vehicle, characterized in that it consists in operating said means periodically (48) when the climatic conditions (54, 58) indicate a risk of blockage of said ventilation means, the operating modes of said means comprising the duration and the frequency Tc of each operating period and being determined according to at least one parameter.

2. Method according to claim 1 characterized in that said operating modes also include the rotational speed of the ventilation means.

3. Method according to one of claims 1 and 2 characterized in that said operating modes are adjusted according to at least one of the following parameters: the temperature outside the vehicle (90), the average speed of the vehicle ( 84), the average fuel consumption of the vehicle, the on / off state of the vehicle front wiper (88) and the vehicle running profile (82) corresponding to the city traffic, to traffic on the road or at a stationary vehicle.

4. Method according to one of the preceding claims characterized in that it further comprises performing at least one test (46) to determine the possible blockage of said ventilation means.

5. The method as claimed in claim 4, characterized in that said test consists of starting (68) said ventilation means and, following the start of said means, determining the appearance (70) of at least one event. characteristic of the blocking of said means.

6. Method according to claim 5, characterized in that a relatively stable operating speed of said motor (64) is detected and said ventilation means are only started if such a steady state is detected, and in that the detecting (70) the occurrence of at least one of the following events characteristic of the blocking of said means: overcurrent of the electric current actuating said ventilation means, decrease of the rotational speed of said internal combustion engine and increase of the fuel consumption of said engine.

7. Method according to one of claims 5 and 6 characterized in that it consists, when a blockage is detected (72), to be placed in the operating conditions at full speed (74) of the ventilation means to try to unlock them.

8. A method according to claim 7 characterized in that a new blocking test is performed (64, 66, 68, 70) immediately after the attempt at full operation and, if a block is detected again, a new attempt operating at full speed is performed (74), the blocking test and unlocking attempt operations being performed until the unlocking of the ventilation means and, if the ventilation means remain blocked after a predetermined number (bmax) of attempts in the unsuccessful unlocking mode, the blocking test and unblocking attempts stop (78) and an alarm (76) indicates to the driver of the vehicle that the vehicle is malfunctioning.

9. Method according to one of claims 4 to 8 characterized in that the test (46) for determining the possible blockage of the ventilation means is systematically performed before the periodic operation (48) of said means for short periods.

10. Method according to one of the preceding claims characterized in that it operates said ventilation means periodically (48) from the start of the internal combustion engine.

11. Method according to one of the preceding claims characterized in that one operates (50) periodically said ventilation means after stopping the internal combustion engine (102).

12. The method of claim 11 characterized in that a test (120) for blocking the ventilation means is performed after each periodic start of the ventilation means.