DESC:FIELD OF INVENTION

The present invention is related to control system for radiator/cooling fan for an automotive road vehicle which normally draws ambient air from the front side of the vehicle and blows it towards engine .The invention is particularly related to control system of a radiator fan employed on a two wheeled vehicle.

BACKGROUND

¬¬A radiator is typically a heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through it by the fan or from natural draft. Radiators are used for cooling internal combustion engines,. Coolant is used in the radiator. The coolant is usually water and glycol based which are mixed in different proportions based on need. Engines operate efficiently at some optimum temperature range. Hence, it is essential to warm-up the engine as early as possible to extract maximum efficiency. However, once the engine has reaches desired operating temperature, it has to be maintained at that temperature to prevent further raise of metal temperature which will otherwise result in mechanical damage of the engine.

Heat is removed from the engine by followings means.
1. Direct radiation/convection from the engine surface to the ambient
2. Heat transfer from engine internal surfaces to the coolant which is thereafter rejected to the air that flows through the radiator.

However, when engine runs at high power for a long time, considerable amount of heat is generated. Once it comes back to low speeds, engine surface receives hot radiator air and hence cannot be cooled as effectively as at high speeds.

For example, when vehicle speed is as low as 10kmph, with very less velocity of ram air available, air through radiator heats up and is blown towards engine by the electric fan (radiator fan).

Further, this hot air unwantedly heats up the other areas near the engine. Typically in case of a two wheeled vehicle the hot air hits the lower portion of the rider’s leg. This situation makes riding uncomfortable. Further, a continuous exposure to such riding condition can cause serious injury to legs, thus posing a very unsafe condition.

These conditions may occur very frequently during summer season and during heavy traffic situations.

Apart from rider injury, the excessive hot air can hamper the functioning of various components of the vehicle, for example battery, regulator etc.

These situations only can exist in two wheeled vehicle wherein there is no separate engine compartment independent from the rider sitting location, which normally is the case in any four wheeled vehicle. Hence, above said problems are not existing in four wheeled vehicles.

Two wheeled manufacturers have avoided the said problems by employing air guide or heat deflectors to pass the hot air away from the engine. Baffle type structures have been employed. One such arrangement is disclosed in US 2013/0168039 titled as Air guide structure of radiator in straddle vehicle. However, these arrangements add cost and weight to vehicle and create lay out, assembly and packaging constraints.

Prior arts of four wheeled vehicles disclose reversal of direction of fan rotation to dissipate the hot air away from the engine bay or to clean the garbage of radiator .However, in case of four wheeled vehicle the hot air is not coming in contact with rider/driver of the vehicle, rather the flow of hot air is limited to engine bay area which is a separate compartment. This is not the situation in case of two wheeled vehicles wherein the engine is in close proximity to the leg resting portion of the rider.

However, the prior arts system/arrangements have limitations and can provide effects to certain extent. These systems/arrangements consume more power, the fan being continuously rotated in forward or reverse direction. Also, there is no provision to diagnose the fault in relation to radiator fan or the input signals which help in deciding the direction of the fan. Absence of such diagnostic mechanism can cause serious damage to engine & vehicle and can pose unsafe conditions to rider and the internal combustion engine under certain operating conditions. Also, these systems do not provide a feedback to the rider on the safe functioning of the fan.

Applicant has designed a radiator/cooling system which mitigates all the above said problems of the prior arts.

OBJECTIVES OF THE INVENTION

• The first object of the invention is to provide a radiator control system to ensure safe & comfortable conditions to rider of the two wheeled vehicle without causing any injury to the rider without compromising on engine cooling.
• Another objective of the invention is to provide a radiator control system which reduces the power consumption for the cooling system and is simple and compact.
• Another objective of the invention is to provide diagnostic system of radiator fan and communicate to rider about malfunctioning in the system.
• Another objective is to have accurate control on the radiator fan functioning thereby achieving faster warm up of engine by reversing the air flow away from the engine until a defined coolant temperature is reached.

DESCRIPTION OF INVENTION

A radiator fan control system for rider comfort and engine cooling for a two wheeled vehicle comprising:
A radiator containing coolant being circulated therein,
A cooling fan driven by a motor; said fan being located behind the said radiator for circulating air,
A radiator fan control unit (RFC) which includes an ECU,
an engine temperature sensing means, a vehicle speed sensing means, an engine rpm sensing means, battery voltage sensing means, a gear position sensing means which includes a neutral switch sensing means. The said radiator fan control unit receives inputs from all above said sensing means and controls initial start up/actuation of radiator fan, direction of rotation of fan (i.e. forward or reverse), rotational speed of fan in forward and reverse direction of rotation of fan on the basis of predefined minimum values and/or threshold values of engine temperature, vehicle speed, engine rpm and battery voltage.

In another aspects the radiator fan control unit is adapted to actuate fan ’ON’ blowing air towards the engine when the engine / coolant temperature is greater than predetermined threshold value (TCI) and the battery voltage is greater than the predetermined minimum battery voltage (MCI).

In another aspects the radiator fan control unit is adapted to actuate the fan ‘ON’ for blowing air towards the engine when the engine or vehicle speed is greater than predetermined minimum engine or vehicle speed (MEI), and the battery voltage is greater than predetermined minimum battery voltage (MBI), or the engine / coolant temperature is greater than predetermined minimum engine / coolant temperature (MCI).

The said control circuit capable of detecting failures or faults in the above signals/input based on various conditions of the said inputs and is capable of initiating corrective measures and a means to communicate failure in the system.

In one aspect of the invention, preferably the radiator fan control unit is microcontroller based.

The first direction of rotation of fan blows air towards engine, the second opposite direction of rotation blows air away from engine.

As per the invention Radiator fan control (RFC) unit is adapted and designed to decide the direction of rotation for the fan considering rider comfort and engine protection. As an embodiment, wheel speed and coolant temperature are used as direct input in taking this decision. Engine speed and battery voltage are used as indirect input from the Engine management system (EMS).However, Engine speed and battery voltage which have been used as indirect input can also be made as direct inputs to Radiator fan control unit.

Switching on radiator fan
As an embodiment, following conditions being sensed to turn the radiator fan ON:
Engine speed >= Minimum speed ( for ex. ~idle) - MEI
Battery voltage > Minimum_volt ( for ex. ~12V) - MBI
Coolant Temperature > Min Limit (>95°C, for ex. )- MCI
If the above conditions are satisfied, the ECU sends a request to turn on the fan ON.

Direction of Fan
Further to decide the direction of the rotations of the fan, when the fan is ON as a one of the embodiment, following conditions are sensed by RFC unit:
a. Fan shall blow air towards engine if
Vehicle speed > VEH1 (for ex. 11kmph) (TV1) OR Coolant Temperature > TEMP1(for ex. 109°C) (TC1)
b. Fan shall blow air away from engine if
Vehicle speed < VEH2 (for ex. 9kmph) (TV1) AND Coolant Temperature < TEMP2( for ex 104°C) (TC1),

Thus rider’s comfort is ensured when the vehicle speed is very less or when the vehicle is stationary at traffic signals. Also, care is taken to protect engine when the coolant temperature is very high.

The above limiting values of temperature, engine rpm, vehicle speed , battery voltage can vary depending upon various conditions like type of engine, engine capacity etc. These variations are covered under the scope of invention.

FAULT DIAGNOSIS

As a further aspect of invention, in addition to above inputs, the RFC unit is capable of sensing the fault/failure diagnosis. The RFC unit senses conditions of various signal i.e. whether input signal is short, open. For example Input in case of battery input signal , the failure conditions could be ‘Short to battery”, “Short to ground”, ‘Open Circuit”. These failures are sensed with respect to values of voltages sensed by controller.
Other fault/failure diagnosis and remedial measures are explained in following paragraph.

The failure signal is displayed at the dashboard panel of the vehicle for alerting the rider about a potential problem. The failure signal can be displayed on external diagnostic tool.

Remedial measures after fault diagnosis

The RFC unit further decides reaction measures when a failure is detected. Thus avoiding damage to parts of vehicle, unnecessary draining of battery etc.
Following table provides details above illustrated failure diagnosis as an example:
Input
Failure Condition Diagnostic Condition @ RFC Limp- Home / Reaction to a Failure Condition
RFI (input from ECU) Short to Battery Close to 5Volts at controller pin Engine speed greater than CPS1rpm is required for T1seconds after which:-
Fan blows air towards Engine if VSS > VEH1kmph OR Coolant temperature > TEMP1degC
Fan blows air away from engine if VSS < VEH2kmph AND Coolant temperature < TEMP2degC.
Short to Ground Close to 0Volts at controller pin; This is equivalent of fan turn on request from ECU, Hence error is diagnosed only when engine and vehicle speed is zero where it is not expected to turn on the fan
Open Circuit 2.5Volts+/-300mvolts at controller pin; This is equivalent of fan turn OFF request from ECU, Hence error is diagnosed when coolant temperature is very hot.
VSS (Wheel Speed) Open Circuit Vehicle speed shall be read as 0 with this current configuration. The vehicle speed is expected to be non-zero if transmission is not in Neutral. If such a condition exist for a predetermined duration, a fault flag is set. Fan blows air towards Engine if Coolant temperature > TEMP1degC OR Transmission is NOT in Neutral
Fan blows air away from engine if Coolant temperature < TEMP2degC AND Transmission is in Neutral.
Short Circuit
Coolant Temperature Open Circuit Error is diagnosed based on different voltage values read bye the microcontroller for each of these fault condition Fan blows air only towards engine as component protection is more important (because a catastrophe like coolant line bursting is more dangerous than hot air hitting the rider leg.)
Short to Sensor Supply
Short to Ground
Neutral Switch Open Circuit Transmission is not expected to be in Neutral if engine speed to vehicle speed ratio is valid enough for a gear ECU request to turn on FAN OR Engine speed is greater than idling speed for a predetermined duration after which:-
Fan blows air towards Engine if VSS > VEH1kmph OR Coolant temperature > TEMP1egC
Fan blows air away from engine if VSS < VEH2kmph AND Coolant temperature < TEMP2degC.
Short Circuit
Fan Motor Open Circuit Diagnosed based on voltage across motor terminals Engine shall heat up till the maximum temperature defined and the EMS system shall Stall the engine after this. This condition shall be communicated to the rider.
Short Circuit

Note: The TEMP1 /TEMP2 and VEH1 / VEH 2 etc. are predefined limiting values of temperature and vehicle speed respectively.

High coolant temperature detection

In a further aspect of invention, the Radiator fan control (RFC) unit provides cooling even when engine speed is zero (vehicle is not running) by putting fan in ON condition. The vehicle is below minimum vehicle speed (MVI). This condition is triggered only for certain duration, based on coolant temperature and status of battery. For example, coolant temperature is very high and the battery is healthy enough to take the load of radiator fan.

In further aspect of invention Radiator fan control (RFC) unit provides variable speed of rotation of radiator fan in forward or reverse direction.
The variable speed control of the radiator fan is done using a pulse width modulated signal. This helps in reducing the total power consumption.

Warm-up condition detected

During initial start up or while it is required that engine to be warmed up at a faster rate , depending upon the vehicle speed , the net flow of air through the radiator can be reduced by altering the fan speed proportional to the vehicle speed and making the fan to operate against the on-coming natural draft. This leads to improvement in engine warm-up condition.

In one aspect the radiator fan control unit is further adapted to give an output warm-up signal to control the speed and direction of fan when the engine coolant temperature is identified less than minimum predetermined engine warm-up temperature (T-MC2) and only until vehicle speed is below the minimum vehicle start speed (MV2).

If vehicle speed is less than pre-determined vehicle speed of "V1" then radiator fan speed "N" is varied from "N1" lowest possible fan speed to "N2" highest rated fan speed depending on vehicle speed "V" and the fan is made to operate in such a way that it opposes the on-coming natural draft.

This warm-up control strategy may be activated when the engine coolant temperature is less than a pre-determined limit "T".

In case, either the vehicle speed reaches above the critical vehicle speed "V1" or the coolant temperature rises to the pre-determined limit of "T", then the warm-up strategy can be switched off and regular strategy to control the fan ON-OFF and forward/ reverse direction may be implemented.

Similarly, radiator fan could be run at highest rated fan speed to cool the engine at faster rate depending on various conditions like engine temperature, vehicle speed etc. Thus avoiding unsafe condition to rider.
Description of invention with reference to accompanying figures.

1. Figure 1 illustrates a flow diagram depicting various logical condition of the RFC controller.
2. Figure 2 depicting rider position on a motorcycle.
3. Figure 3a and 3 b illustrate a close up view of radiator, fan and air flow directions.
4. Figure 4a and 4b illustrates detailed views of directions of rotation of fan and corresponding air flow direction.
5. Figure 5 is a circuit diagram of Radiator fan control unit (RFC) according to one of the embodiment of invention.
6. Figure 6 is a circuit diagram of Radiator fan control unit (RFC) according to another embodiment of invention.
7. Figure 7a and 7b illustrate two alternative sensing configurations according to invention.
Figure 1 discloses various conditions and signals sensed by the RFC controller (15) for starting up the fan and various actions such as forwarding and reversing direction of the radiator fan along with various failure diagnosis sensing.

Figure 2 shows a motorcycle (20) having an engine (20a) and a rider (21) riding the said motorcycle. The motorcycle employs a radiator (22) at the front side of the vehicle across its width and radiator fan (24) located behind the said radiator.

It can be observed that lower portion of leg (23) of the said rider is postured very near to engine and at the backside of radiator fan.

Thus while the fan is rotating in forward direction to blow the air towards engine, the blown air always hits the said leg portion (23). Thus when engine is hot and running at low speed or or heavy traffic condition , the hot air blown by fan towards engine hits this portion of leg which makes riding uncomfortable. Such conditions prevailing for longer duration causes injury to this leg portion of the rider leading to a highly unsafe condition.

Thus according to the invention, the RFC controller (15) senses these conditions and reverses the direction of radiator fan so as to blow air away from engine and preventing unsafe condition which can otherwise cause injury to rider’s leg.
Figure 3a and 4a illustrate that while the fan (24) is rotating in forward direction the air is blown towards engine and toward the leg of the rider with respect to above described conditions related to vehicle speed, engine speed, battery voltage, engine coolant temperature as applicable.
Figure 3b and 4b illustrate that rotation of fan in reverse direction (i.e. opposite to forward direction), the air is blown away from the engine and leg of the rider with respect to above described conditions related to vehicle speed, engine speed, battery voltage, engine coolant temperature as applicable . Thus not making the rider uncomfortable or causing any harm to rider’s leg.
Alternatively, the direction of rotation of fan can be termed as clockwise and anticlockwise as applicable.
Figure 5 is a circuit diagram of Radiator fan control unit (RFC) according to invention .This comprises a controller i.e. RFC controller (15) receiving input signal for vehicle speed sensing means (11), input for engine rpm from a rpm sensing means (12), engine temperature sensing input from Engine coolant temperature sensing means (10), fan enabling signal from Engine management system( 9) and input signal from neutral switch sensing means (1)to judge gear position, a Battery Voltage signal sensing means(19).The battery voltage signal is through a relay (R), however this input can be sought directly.
Output signals from the said RFC controller unit being sent to one of the relay circuits (16,17) to run the fan in forward or reverse direction respectively and with required rotational speed with respect to above described conditions with respect to vehicle speed, engine speed, battery voltage, engine coolant temperature as applicable.
The said circuit is comprising feedback signals (4) & (8) and feedback circuit (18) to the said RFC controller to check proper working of fan as per output signal or to know malfunctioning of the fan.
Absence of such feedback system can cause serious damage to engine & vehicle and can pose unsafe conditions.
As one of the alternatives, as disclosed in Figure 6, the Radiator fan control unit (RFC) according to invention can be provided with H bridge arrangement (30) to control radiator fan speed precisely. This arrangement avoids need of relay circuits while all the other functions like forwarding/reversing signals and feedback signals can be performed by the H bridge arrangement.
The sensing means, methods and sensing locations could be varied. However, as an example, the figure 5 discloses that vehicle speed is sensed through ABS (Antilock braking system), Engine speed is sensed through crank position sensor. Engine temperature is sensed by sensing engine coolant temperature. The batter voltage is sensed through a relay system (R), however can sensed directly by the RFC.
All these input signals can be sensed directly by RFC as disclosed in figure 7b or few signals could be sought through EMS (Engine Management system) as disclosed in figure 7a.
Scope of the patent is not just limited for use with an EMS system (or Fuel Injected engines).
All these functionalities could also be employed to a carburetted two wheeled vehicle by employing CDI (Capacitive discharge Ignition system) or IDI (Inductive discharge Ignition) system along with RFC unit.
Further, the invention is applicable to an electric two wheeled vehicle wherein the motor and battery temperature can be monitored and above mentioned radiator fan control can be exercised.
Variations and modifications known to person skilled in the art are covered under the scope of invention. ,CLAIMS:1. A radiator fan control system for rider comfort and engine cooling for two wheeled vehicle comprising

a. a radiator containing coolant circulated there within,
b. a radiator fan driven by a motor for blowing air,
c. a radiator fan control unit including an ECU (9),
d. an engine temperature sensing means (10) for sensing engine temperature,
e. a vehicle speed sensing means (11) for sensing vehicle speed,
f. an engine rpm sensing means (12) for sensing engine rpm,
g. a battery voltage sensing means (19) to sense the battery voltage, and
h. a gear position sensing means including a neutral switch sensing means.
i. wherein the said radiator fan control unit is a microcontroller (15) based unit adapted to receive inputs from all above said sensing means and generating output signal which controls the actuation of said radiator fan, the direction of rotation of the fan and the rotational speed of the fan on the basis of predefined minimum values and/or threshold values of engine temperature, vehicle speed, engine rpm and battery voltage.

2. The radiator fan control system as claimed in claim 1, wherein the radiator fan control unit is adapted to actuate fan ’ON’ blowing air towards the engine when the engine / coolant temperature is greater than predetermined threshold value (TCI) and the battery voltage is greater than the predetermined minimum battery voltage (MCI).

3. The radiator fan control system as claimed in claim 1, wherein said radiator fan control unit is adapted to actuate the fan ‘ON’ for blowing air towards the engine when the engine or vehicle speed is greater than predetermined minimum engine or vehicle speed (MEI), and the battery voltage is greater than predetermined minimum battery voltage (MBI), or the engine / coolant temperature is greater than predetermined minimum engine / coolant temperature (MCI).

4. The radiator fan control system as claimed in claim 1 and 3, wherein said radiator fan control unit is further adapted to actuate fan blowing air away from the engine when the vehicle speed is equal or less than threshold vehicle speed (TVI) and when engine / coolant temperature is equal or less than threshold engine / coolant temperature (TCI).

5. The radiator fan control system as claimed in claim 1 and 3, wherein said radiator fan control unit is further adapted to actuate fan blowing air towards the engine when vehicle speed is greater than predetermined threshold vehicle speed (TVI).

6. The radiator fan control system as claimed in claim 1, 3 and 5, wherein said radiator fan control unit is further adapted to actuate fan blowing air towards the engine when engine / coolant temperature is greater than predetermined threshold engine / coolant temperature (TCI).

7. The radiator fan control system as claimed in claim 1 only, wherein the radiator fan control unit is adapted with a bidirectional radiator fan.

8. The radiator fan control system as claimed in claim 1 only, wherein the radiator fan control unit is adapted with a variable speed radiator fan.

9. The radiator fan control system as claimed in claim 1 only, wherein the radiator fan control unit is adapted with a radiator fan operable using pulse width modulated signal for variable speed control.

10. The radiator fan control system as claimed in claim 1 only, wherein the radiator fan control unit is adapted with H bridge arrangement to control the radiator fan speed and direction.

11. The radiator fan control system as claimed in claim 1 only, wherein the radiator fan control unit is further adapted to give an output warm-up signal to control the speed and direction of fan when the engine coolant temperature is identified less than minimum predetermined engine warm-up temperature (T-MC2) and only until vehicle speed is below the minimum vehicle start speed (MV2).

12. The radiator fan control system as claimed in claim 1 only, wherein the radiator fan control unit is adapted to actuate fan blowing air through ECU and blowing air towards the engine when the engine / coolant temperature is greater than predetermined threshold value (TCI) and the battery voltage is greater than the predetermined minimum battery voltage (MCI) even if the engine speed is less than predetermined minimum engine speed (MEI).

13. The radiator fan control system as claimed in claim 1 further adapted with plurality of fault detection means to detect plurality of irregularities in the above received input signals based on predefined stored input signal conditions of the said corresponding inputs and generating a corresponding output fault signal which is representation of irregularity condition in the vehicle.

14. The radiator fan control system as claimed in claim 13, wherein the output fault signal may be a display signal, and which display signal may be displayed on the dashboard or external diagnostic tool of the vehicle.

15. The radiator fan control system as claimed in claim 13, wherein said output fault signal from RFI so generated controls the actuation of said radiator fan, the direction of rotation of fan, and the speed of the fan, on the basis of minimum values and/or threshold values of engine temperature, vehicle speed, engine speed and battery voltage and of which atleast one of the detected input signal is identified with irregularity.

16. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a fault condition in ECU and blows air towards the engine when vehicle speed is greater than predetermined threshold vehicle speed (TV1).

17. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a fault condition in ECU and blows air towards the engine when the coolant temperature is greater than predetermined threshold coolant temperature (TC1).

18. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a fault condition in ECU and blows air away from engine when vehicle speed is equal or less than threshold speed (TV1) and engine / coolant temperature is equal or less than threshold engine / coolant temperature (TC1).

19. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a fault condition in wheel speed sensor and blow air towards engine when coolant temperature is greater than predetermined coolant temperature (TC1).

20. The radiator fan control system as claimed in claim 13 when the fault detection means identifies a fault condition in wheel speed sensor and blow air wherein said radiator fan control unit is further adapted to actuate fan blowing air towards the engine when the vehicle transmission is not in neutral.

21. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a fault condition in wheel speed sensor and blows air away from engine when the coolant temperature is equal or less than threshold coolant temperature (TC1) and vehicle transmission is in neutral.

22. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a fault condition in coolant temperature sensor and blows air towards the engine.
23. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a neutral switch fault and blows air towards the engine when vehicle speed is greater than predetermined threshold speed (TV1C).
24. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a neutral switch fault and blows air towards the engine when the coolant temperature is greater than predetermined threshold coolant temperature (TC1).
25. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a neutral switch fault and blows air away from engine when vehicle speed is equal or less than threshold speed (TV1) and engine / coolant temperature is equal or less than threshold engine / coolant temperature (TC1).
26. The radiator fan control system as claimed in claim 13, wherein said radiator fan control unit is adapted to actuate the fan ON for blowing air when the fault detection means identifies a fault condition in fan motor and allows the engine to heat up until predetermined maximum temperature and thereafter stall the engine through EMS of the vehicle.
27. The radiator fan control system as claimed in claim 1, wherein the radiator fan unit further includes the a controller (15) adapted to receive plurality of input signals from vehicle speed sensing means (11) engine temperature signal means (10), engine rpm signal means (12), a battery voltage sensing means (19), fan enabling signal from ECU (9), neutral switch sensing means (1) and to generate controlled plurality of outputs to the radiator fan with a feedback means (4,8 & 18) mutually associated with the controller and radiator fan for identifying continuously the operational condition of the fan.