DESC:TECHNICAL FIELD
[0001] The present subject matter relates to a vehicle. More particularly, the present invention relates to a vehicle cooling system and a method thereof.
BACKGROUND
[0002] An internal combustion engine commonly employs a pressurized cooling system with a circulating liquid coolant for cooling the engine. The liquid coolant is circulated through a radiator type heat exchanger. An electrically operated radiator cooling fan is used to promote heat transfer between the surrounding atmosphere and the radiator. Depending on the determination of engine coolant temperature the operation of the radiator cooling fan is controlled. The engine coolant temperature is maintained within predetermined limits to ensure optimum engine operating temperature and thereby maximize engine efficiency. However, this type of radiator cooling system is generally employed for vehicles with large engine capacity where natural air draft is not sufficient to cool the engine efficiently.
[0003] During radiator cooling fan operation, air flow direction is from the front side of the vehicle towards the radiator and then to the engine. The radiator cooling fan operation directs hot air towards the engine. In a motorcycle type two-wheeled vehicle, the rider’s legs are positioned close to the engine and the hot air directed from the radiator towards the engine causes rider discomfort.
[0004] A known cooling system for internal-combustion engines consist of radiator, radiator cooling fan shroud and compensator reservoir wherein rider discomfort due to hot air directed by the coolant fan is avoided by adding a thermal insulation between exhaust pipe and the cooling fan blade. But such a design reduces air flow and increases weight and cost of the system.
[0005] In another known cooling system for internal combustion engine, cooling fan actuation, speed and direction are controlled based on engine speed, battery voltage, vehicle speed and coolant temperature to ensure that hot air is not directed to the rider’s legs. When the cooling fan direction is reversed, hot air is sucked away from the engine and radiator is cooled at a lower rate. Also, in a motorcycle type two-wheeled vehicle, a shroud is used to prevent hot air from being directed towards the rider’s legs. The shroud covers the lateral sides of the cooling fan and is only open towards the downward end of the radiator and therefore hot air is directed towards the downward end of the radiator. But such a shroud increases the weight and cost of the system.
[0006] It can also be seen that in certain known cooling systems for internal combustion engine the deterioration of power supply voltage due to continuous operation of cooling fan during abnormal operation of coolant temperature sensor is avoided by intermittently driving the cooling fan for engine speed lower than a threshold.
[0007] One known arrangement of the cooling system to perform cooling by circulating the cooling water is through an arrangement of radiator cooling fan that streams hot air in the same direction as the advancing direction of the motorcycle to avoid discomfort to the rider. However, such arrangement avoids discomfort only for high vehicle speeds. The problem of rider discomfort while riding at low speed and with high engine load still persists.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0009] Fig. 1 is a circuit diagram of a vehicle cooling system for a liquid-cooled engine, according to one embodiment of the present invention.
[00010] Fig. 2 illustrates a flowchart describing a method for controlling the vehicle cooling system in accordance with one embodiment of the present invention.
[00011] Fig. 3 illustrates a block diagram illustrating the vehicle cooling system as per one embodiment of the present invention.

DETAILED DESCRIPTION
[00012] Liquid cooled engines have a radiator for cooling a coolant. A radiator cooling system comprises passages inside the engine block and heads, a water pump to circulate the coolant, a thermostat to control temperature of the coolant, a radiator to cool the coolant, a radiator cap to control the pressure in the system, and some plumbing consisting of interconnecting hoses to transfer the coolant from the engine to radiator.
[00013] The radiator cooling system works by sending a liquid coolant through passages in the engine block and head. As the coolant flows through these passages, it picks up heat from the engine. The heated fluid then makes its way through a rubber hose to the radiator at a front side of the vehicle. As it flows through the thin tubes in the radiator, the hot liquid is cooled by air stream entering from fins in front of the vehicle. Once the fluid is cooled, it returns to the engine to absorb more heat. A water pump performs the function of keeping the coolant moving through this system of plumbing and hidden passages. The coolant follows a path that takes it from the water pump through passages inside the engine block where it collects heat produced by the engine cylinder. It then flows up to the cylinder head where it collects more heat from the combustion chamber.
[00014] A thermostat is placed between the engine and the radiator to make sure that the coolant stays above a certain pre-set temperature. If the coolant temperature falls below this temperature, the thermostat blocks the coolant flow to the radiator, forcing the fluid instead through a bypass directly back to the engine. The coolant will continue to circulate like this until it reaches the desired temperature, at which point, the thermostat will open a valve and allow the coolant back through the radiator.
[00015] An electrically operated radiator cooling fan is used to promote heat transfer between the surrounding atmosphere and the radiator. When the engine coolant temperature exceeds a predetermined value, the coolant fan is turned ON to increase the rate of heat transfer and cool the engine. The cooling fan will be turned OFF once the coolant temperature goes below a second predetermined value. The engine coolant temperature is maintained within predetermined limits to ensure optimum engine operating temperature and thereby maximize engine efficiency.This type of radiator cooling system is generally employed for vehicles with large engine capacity where natural air draft is not sufficient to cool the engine efficiently. During radiator cooling fan operation, air flow direction is from the front side of the vehicle towards the radiator and then to the engine. If the engine is operating at high load for a long duration such as when climbing a hill, the heat generated will be immense. In such a case, the heat transferred to the coolant will also be high which in turn will result in high temperature in the radiator. The cooling fan operation will thus direct hot air towards the engine.
[00016] In a known motorcycle type two-wheeled vehicle, the rider’s legs are positioned close to the engine and the hot air directed from the radiator towards the engine will cause rider discomfort. Particularly, when the vehicle is moving at low speeds, the natural air draft will be insufficient to cool the rider’s body and the hot air blown by the cooling fan can lead to skin irritation. The rider might choose to stop the vehicle and move away to allow the engine to cool naturally before continuing the ride. The hot air directed towards the rider’s body will also heat the vehicle body parts like cowl and side panels and accelerate deterioration. Also during winter season or in places with cold climatic conditions, rider feels cold and it will be beneficial if hot air is directed at the rider’s body. Also while riding in heavy traffic conditions inside city, there is a possibility that engine temperature shoots up rapidly and frequent ON/OFF of cooling fan is required to increase the cooling capacity which also increases electrical power consumption. This high power demand might lead to quick discharge of vehicle battery.
[00017] It will be beneficial if the vehicle cooling system can be controlled to prevent hot air from being directed to the rider’s legs during low speed operation of the vehicle and allows hot air towards the rider during cold weather conditions without deteriorating engine efficiency and durability. Also, with the controlling operation of the radiator cooling fan motor, engine cooling systems operation will be efficient to avoid costly repairs that may result from excessive temperature.
[00018] With these objectives in view, the present invention discloses a vehicle cooling system and a method thereof for controlling a radiator cooling fan of a liquid -cooled engine. As per one embodiment of present invention, the vehicle cooling system for controlling the coolant temperature involves the intermittent operation of the radiator cooling fan motor based on a signal being processed by the electronic control unit (ECU) and hence reduces the power consumption. Moreover, significant thermal efficiency and fuel consumption is achieved by intermittently driving the radiator cooling fan motor for engine speed based on certain predetermined coolant temperature values. With the one embodiment as per present invention, the method for controlling the on/off of the radiator cooling fan motor by sensing intake temperature after the signal from ambient temperature sensor being processed by the Electronic Control Unit (ECU) achieves the purpose of improving the thermal efficiency of the engine.Additionally, the system for controlling a radiator cooling fan of a liquid-cooled engine according to the present invention provides comfort to the rider during cold weather condition.
[00019] The vehicle cooling system for cooling the liquid-cooled engine has advantages and effects of improvements on energy conservation, durability, fuel consumption and hence contributes in improving the thermal efficiency of the internal combustion engine.
[00020] Various other features and advantages of the invention are described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number. With reference to the accompanying drawings, wherein the same reference numerals will be used to identify the same or similar elements throughout the several views. It should be noted that the drawings should be viewed in the direction of orientation of the reference numerals.
[00021] Although the present invention has been exemplified for the two-wheeled vehicle, it is not restricted only for the two-wheeled vehicle. Application of the present invention may be extended to other vehicles, including three-wheeled vehicles and four –wheeled vehicles.
[00022] Fig.1 illustrates a circuit diagram (1) of a vehicle cooling system (200) for controlling an electrically operated radiator cooling fan (12) (shown in Fig.2) of a liquid-cooled engine as per one embodiment of the present invention. In one embodiment, the system (200) for controlling the electrically operated radiator cooling fan (12) comprises the radiator (13) made up of aluminium, coolant which circulates along coolant tubes (16) inside the radiator (13), the radiator cooling fan (12) which is driven by an electric PMDC (Permanent Magnet Direct Current) or BLDC (Brushless Direct Current) motor (9) mounted at a rear side of the radiator (13) to suck natural air from atmosphere and provide it to the radiator (13). In one embodiment, the fan motor (9) drives the radiator cooling fan (12) by switching ON/OFF an electromechanical relay (6) based on inputs from a coolant temperature sensor (10), engine speed sensor (2), vehicle speed sensor (3), and ambient temperature sensor (4). The battery (8) supplies electrical power for operation of one or more vehicle electrical loads including the fan motor (9). In one embodiment, said circuit diagram (1) includes a fuse (7) protects wiring against short circuit conditions.
[00023] Further in Fig.1, according to one embodiment, the coolant temperature sensor (10) provides a coolant temperature signal to an electronic control unit (ECU) (5), the ambient temperature sensor (4) provides an ambient environment temperature signal to the an electronic control unit (ECU) (5). In one embodiment, said engine speed sensor (2) produces an engine speed signal and is connected to the Electronic Control Unit (ECU) (5). As per one embodiment, the engine speed sensor (2) is being processed by the Electronic Control Unit (ECU) (5) for determining the engine speed (2). In one embodiment, said radiator (206) provides cooling of the liquid- cooled engine. As per one embodiment, the Electronic Control Unit (ECU) (5) after receiving signal from said engine speed sensor (2) determines an idling condition of the engine, and controls an actuation of the fan motor (9) based upon said coolant temperature signal and said intake air temperature signal received from said coolant temperature sensor (10) and said ambient temperature sensor (4) respectively, such that the radiator cooling fan (12) is operated when said coolant temperature is greater or equal to one or more predetermined coolant temperature values.
[00024] Fig. 2 illustrates the block diagram (200) of the system (1) for controlling the electrically operated radiator cooling fan (12) of the liquid-cooled engine as per one embodiment of the present invention. In one embodiment, at block (201), the ambient air temperature sensor (14) is positioned at a site close to the outside of intake side of engine. In one embodiment, said air temperature sensor (14) captures the temperature of the ambient air and is located in the air duct for the intake air. At block (202), the radiator cooling fan (12) including at least a four blade fan configuration is provided on the engine side of the radiator to draw air there through, rotation of the fan blade being directly related to the engine speed (21). Thus, the slower the engine speed (21), the slower is the rotation of radiator cooling fan (12) thus, the resulting in a smaller quantity of forced air flow. Input sensors are selected from a group consisting of the coolant temperature sensor (10), the vehicle speed sensor (3) and the ambient temperature sensor (14), for providing signals being processed by the electronic control unit (ECU) (5). More particularly, respective sensors are situated on the vehicle chassis. At block (203), the electronic control unit (ECU) (5) is connected to a terminal of a wire harness at block (204). In one embodiment, the coolant temperature sensor (10), ambient air temperature sensor (14), the electric water pump and the radiator cooling fan (12) are respectively connected with the electronic control unit (ECU) (5).The wire harness, at block (204), is passed to the engine and through a grommet is locked to the vehicle body panel.
[00025] At block (205), at least one electric fan as the radiator cooling fan (12) for supplying air to said radiator. The radiator cooling fan (12) rotates based on the drive of the fan motor (9). At block (206), the vehicle cooling system (1) for the liquid-cooled engine comprises the radiator (13) for cooling the engine coolant at block (207). The engine is cooled with this cooled cooling water. At block (208) and block (209), coolant (14) circulates along coolant tubes (16) inside the radiator (13). In one embodiment, said coolant tubes (16) provides for flow of the coolant (14) between a pair of spaced liquid coolant tanks (15). Further the fan motor (9) operation can also be controlled based on the vehicle speed signal obtained from the vehicle speed sensor (3). At block (210), a thermostat (17) is installed to a transmission while a coolant pump is installed at the front end section of a cylinder block. At block (211), the impeller (18) rotates the fan motor (9) as a drive source different from the ordinary water pump for a drive source to a crankshaft of the engine. The radiator cooling fan (12) provides the cooling of the engine coolant (14) in the radiator (13). At block (212), the heated coolant (14) from a coolant jacket (19) of the cylinder block flows through a conduit to the radiator (13). The coolant (14) from the thermostat (17) flows into the coolant pump. In one embodiment, the ccoolant jacket (19) surrounds the cylinder wall, and is spaced therefrom so as to define a block coolant chamber. A coolant pipe is provided to fluidly connect the thermostat (17) and the coolant pump. As per one embodiment, the radiator (13) comprises of said pair of spaced liquid coolant tanks, one of which is an inlet tank having a liquid coolant inlet adjacent one end and the other of which is a liquid outlet tank having an outlet adjacent to its corresponding opposite end. At block (213), the electronic control unit (ECU) (5) receives the signal from the coolant temperature sensor (10) for detecting the cooling water temperature. The coolant temperature sensor (10) is front side mounted into the engine cylinder head .When the temperature of the coolant temperature is higher than the predetermined temperature, the radiator cooling fan (12) is rotated to rapidly reduce the temperature of the coolant (14), however, when the temperature of the engine coolant is below the predetermined temperature, results in slow rotation of the radiator cooling fan of the engine and thus can improve riding comfort when the rider is moving in slow traffic conditions wherein the hot air directed towards the rider is not cooled due to ram air from the environment. While one embodiment has ON/OFF control of the radiator cooling fan based on said predetermined values of coolant temperature, intake air temperature and engine speed, the operation of the fan motor (15) can be a function of coolant temperature, intake air temperature, engine speed and vehicle speed. Further the coolant fan motor speed can also be a function of the above mentioned variables to allow greater control of hot air directed towards the rider.
[00026] Fig. 3 shows a flowchart illustrating a method (100) for controlling the vehicle cooling system (200). In one embodiment, said method (100) for controlling the vehicle cooling system (1) comprises following steps: the electronic control unit (ECU) (5) is connected to an engine key switch (ignition switch) as in step 101. The key switch is operable manually by a vehicle driver to start and stop the engine. As per one embodiment, a starter is driven to start the engine when the key switch is turned on manually or when a predetermined automatic engine start condition is satisfied. In one embodiment, the electronic control unit (ECU) (5) is connected to one or more sensors and switches that detect operating conditions of the engine or vehicle. The electronic control unit (ECU) (5) also supplies a motor control circuit such as a electromechanical relay (20), for example, with an ON/OFF command signal from the coolant temperature sensor (10), the ambient temperature sensor (14), the engine speed sensor (2), such that a driving current can be supplied intermittently from the battery to the fan motor via the motor control circuit thus controlling the fan motor (9). The vehicle speed sensor (3) detects a travel speed of the vehicle, and the engine speed sensor (2) detects a rotation speed of an engine crankshaft. As per one embodiment, said electronic control unit (ECU) (5) determines the engine speed. In step 103, the determination of idling condition of the engine speed (21) according to the present invention is achieved based on a signal received by the electronic control unit (ECU) (5) from the engine speed sensor (3) after start of the engine. If the engine speed (21) is above and equal to 1700 rpm, then said engine speed (21) is not in idling condition. If engine speed (21) is below 1700 rpm, then said engine speed (21) is in idling condition. As per one embodiment of the present invention in step 103, if the engine is judged to be in an idling speed, the electronic control unit (ECU) (5) in step 104, checks that whether a coolant temperature is greater than and equal to a first predetermined coolant temperature value (110 degC in one embodiment of the present invention) based on a signal received from the coolant temperature sensor (10). In step 105, when the coolant temperature is less than and equal to the first predetermined coolant temperature value (110 degC in one embodiment of present invention), the electronic control unit (ECU) (5) checks that whether an intake air temperature is less than and equal to a predetermined ambient temperature value (15 degC in one embodiment of present invention). In step 106, if the intake air temperature is less than and equal to the predetermined ambient temperature value (less than 15 degC in the preferred embodiment), then the electronic control unit (ECU) (5) checks whether the coolant temperature is greater than a third predetermined coolant temperature value. In step 107, if the coolant temperature is greater than a third predetermined coolant temperature value, then the fan motor (9) is actuated. This allows the hot air from the radiator to be directed towards the legs of the rider and improves his/her comfort in cold weather conditions. When the rider is at standstill idling condition on a cold day, the cooling fan operation can provide some warmth and improve rider comfort. Thereafter the coolant temperature and engine speed are monitored continuously. In step 108, the electronic control unit (ECU) (5) checks the coolant temperature. Referring to one embodiment, in step 110, the electronic control unit (ECU) (5) checks whether said coolant temperature is less than and equal to fourth predetermined value (65degC in one embodiment of present invention). In step 112, if the coolant temperature reduces below the fourth predetermined value (65 degC in one embodiment of present invention), then the coolant fan motor (9) is deactuated, and if the coolant temperature is above the fourth predetermined value (65 degC in one embodiment of present invention), then the electronic control unit (ECU) (5) checks the coolant temperature again. Thus, riding comfort is improved during cold weather conditions and hot air is prevented from approaching the rider’s legs during brief standstill condition with high engine temperature.
[00027] In step 109, the electronic control unit (ECU) (5) checks the engine speed. In step 111, the electronic control unit (ECU) (5) determines whether the engine speed is in idling condition. In step 112, if the engine speed exceeds the idling condition, then the fan motor (9) is deactuated and electronic control unit (ECU) (5) checks the engine speed again. Further, referring to one embodiment, in step 114, if the coolant temperature is greater than and equal to the first predetermined coolant temperature value, then the radiator fan motor (9) is actuated. By actuating the radiator cooling fan motor for coolant temperature exceeding the first predetermined value, the heat from the radiator is transferred to the external environment at a faster rate thereby reducing the coolant temperature.In step 115, the electronic control unit (ECU) (5) checks whether the coolant temperature is less than and equal to a second predetermined coolant temperature value (95degC in one embodiment of present invention). In step 116, if the coolant temperature is less than and equal to the second predetermined coolant temperature value (95degC in one embodiment of present invention) then the fan motor (9) is deactuated. This ensures that the hot air from the radiator (13) and engine will not be directed towards the rider’s legs if he/she comes to a standstill idling condition briefly after driving at high loads for a long duration.
[00028] Further, in Fig.3, if engine is judged to be in speeds exceeding idling condition, then in step 113, the coolant temperature is checked based on signal from the coolant temperature sensor and, if it is greater than and equal to a fifth predetermined coolant temperature value (= 105degC in one embodiment of the present invention) then the step 114 is repeated and the fan motor (9) is actuated by driving the relay coil. Thereafter the coolant temperature is continuously monitored and hence the step 115 is repeated. In one embodiment, in step 115, when the coolant temperature decreases below a second predetermined value (95degC in one embodiment) then the fan motor (9) is deactuated by de-energizing the relay coil.
[00029] Advantageously, as per the present invention, the intermittently switching on/off of fan motor facilitates in durability , efficiency , reliability , energy saving, fuel consumption in internal combustion engine and thermal management of ECU. As per one embodiment of present invention, the operation of cooling fan prevents hot air from being directed to the rider’s legs during low speed operation of the vehicle and allows hot air towards the rider during cold weather conditions without deteriorating engine efficiency and durability.
[00030] Improvements and modifications may be incorporated herein without deviating from the scope of the invention.
,CLAIMS:I/We Claim:
1. A vehicle cooling system (1) for a liquid-cooled engine, said system (1) comprising :
a radiator (13) through which at least a portion of a coolant (14) from the engine passes;
a radiator cooling fan (12) disposed to draw ambient air across at least a portion of the radiator (13), said radiator cooling fan (12) having a fan motor (9);
a coolant temperature sensor (10) detecting a coolant temperature;
an ambient temperature sensor (4) detecting an intake air temperature;
an electronic control unit (ECU) (5) receiving a coolant temperature signal and an intake air temperature signal from said coolant temperature sensor (10) and said ambient temperature sensor (4) respectively; and
wherein said electronic control unit (ECU) (5) controls an actuation of the fan motor (9) based upon said coolant temperature signal and said intake air temperature signal received from said coolant temperature sensor (10) and said ambient temperature sensor (4) respectively, such that the radiator cooling fan (12) is operated when said coolant temperature is greater or equal to one or more predetermined coolant temperature values.
2. The vehicle cooling system (1) as claimed in claim 1, wherein said fan motor (9) is an electric PMDC (Permanent Magnet Direct Current) and a BLDC (Brushless Direct Current) motor.
3. The vehicle cooling system (1) as claimed in claim 1or claim 2, wherein said fan motor (9) is mounted at a rear side of the radiator (3).
4. The vehicle cooling system (1) as claimed in claim 1, wherein said fan motor (9) is controlled by switching ON/OFF an electromechanical relay (6) based on inputs from said coolant temperature sensor (10) and the ambient temperature sensor (4).
5. A method (100) for controlling a vehicle cooling system (1) for a liquid -cooled engine, said method (100) comprising the steps of:
determining by an ECU (5), whether an engine speed (21) is in idling condition based on an engine speed signal received from an engine speed sensor (2);
checking by the ECU (5), whether a coolant temperature is lesser than one or more predetermined coolant temperature values based on a coolant temperature signal received from a coolant temperature sensor (10);
checking by the ECU (5), whether an intake air temperature is below a predetermined ambient temperature value based on an intake air temperature signal received from an ambient temperature sensor (4); and
selectively actuating a fan motor (9) in response to the coolant temperature signal and ambient temperature signal from said coolant temperature sensor (10) and ambient temperature sensor (4) respectively.
6. The method (100) for controlling the vehicle cooling system (200) as claimed in claim 1,wherein said method (100) of determining by the ECU (5), whether the engine speed (21) is in idling condition based on the engine speed signal received from the engine speed sensor (2), comprises step of:
if engine speed is above and equal to 1700 rpm, then said engine speed is not in idling condition;
if engine speed is below 1700 rpm, then said engine speed is in idling condition.
7. The method (100) for controlling the vehicle cooling system (200) as claimed in claim 1or claim 6, wherein if said engine speed (21) is in idling condition then said method of checking by the ECU (5), whether the coolant temperature is lesser than said one or more predetermined coolant temperature values based on the coolant temperature signal received from the coolant temperature sensor (10) comprises steps of:
checking by the ECU (5), whether a coolant temperature is lesser than a first predetermined coolant temperature value based on the coolant temperature signal received from the coolant temperature sensor (10);
if said coolant temperature is greater than a first predetermined coolant temperature value, actuating the fan motor (9);
if said coolant temperature is lesser than a first predetermined coolant temperature value then the ambient temperature is determined.
8. The method (100) for controlling the vehicle cooling system (200) as claimed in claim 1or claim 7, wherein if said coolant temperature is lesser than the first predetermined coolant temperature value, then method of checking by the ECU (5), whether the ambient temperature is below a predetermined ambient temperature value based on the intake air temperature signal received from the ambient temperature sensor (4) comprises steps of:
if said ambient temperature is below a predetermined ambient temperature value then one or more predetermined coolant temperature values is determined;
repeating, by the ECU (5), the preceding steps if ambient temperature is greater than a predetermined ambient temperature value.
9. The method (100) for controlling the vehicle cooling system (200) as claimed in claim 1or claim 8, wherein if said ambient temperature is below a predetermined ambient temperature value,
checking by the ECU (5), whether said coolant temperature value is greater than a third predetermined coolant temperature value based on a signal received from said coolant temperature sensor (10),

if coolant temperature greater than a third predetermined value, the fan motor (9) is actuated,
repeating, by the ECU (5), the preceding steps if coolant temperature is lesser than a third predetermined value.
10. The method (100) for controlling the vehicle cooling system (200) as claimed in claim 1or claim 9, wherein if coolant temperature greater than said third predetermined value, then
checking by the ECU (5), whether said coolant temperature lesser than a fourth predetermined value based on a signal received from said coolant temperature sensor (10),
if said coolant temperature lesser than a fourth predetermined value based on a signal received from said coolant temperature sensor (10), deactuating the fan motor (9);
repeating, by the ECU (5), the preceding steps after deactuating the fan motor (9);
checking the coolant temperature if said coolant temperature greater than a fourth predetermined value;
repeating, by the ECU (5), the preceding steps if coolant temperature is lesser than a third predetermined value;
repeating, by the ECU (5), the preceding steps if the count is not equal to the first predetermined count value.