Claims:We claim:
1. A control unit (110) to estimate intake air temperature for an engine (120) of a vehicle, said engine (120) coupled with an intake manifold (118) and provided with a temperature sensor (102), said control unit (110) configured to:
receive signals for input variables comprising an engine temperature, an air mass flow through said intake manifold (118) and an ambient temperature, and
determine said intake air temperature using said input variables, characterized in that,
said intake air temperature is determined through a temperature model (106) derived using regression analysis, said temperature model (106) stored in a memory element (104) of said control unit (110).

2. The control unit (110) as claimed in claim 1, wherein said ambient temperature is estimated using at least one selected from a group comprising a set of parameters, related to said engine temperature, measured and stored in said memory element (104) and a connected device (114), wherein said connected device (114) is at least one of a cluster unit of said vehicle and a communication unit of a user.

3. The control unit (110) as claimed in claim 2, wherein to estimate said ambient temperature using said set of parameters, said control unit (110) configured to
measure and store said set of parameters comprising,
a first temperature at a stop of said engine (120) and a corresponding time of stop in a previous drive cycle, and
a second temperature at a start of said engine (120) and corresponding time of start in a current drive cycle,
calculate a time difference between said start and said stop of said engine (120),
calculate a temperature difference between said first temperature and said second temperature, and
while at least one of said time difference and said temperature difference is less than respective thresholds, estimate said ambient temperature as a function of said set of parameters.

4. A control unit (110) to estimate ambient temperature for a vehicle, said vehicle comprises a temperature sensor (102) for an engine (120) of said vehicle, characterized in that, said control unit (110) configured to:
measure and store a set of parameters comprising,
a first temperature at a stop of said engine (120) and a corresponding time of stop in a previous drive cycle,
a second temperature at a start of said engine (120) and a corresponding time of start in a current drive cycle, and
calculate a time difference between said start and said stop of said engine (120),
calculate a temperature difference between said first temperature and said second temperature, and
while at least one of said time difference and said temperature difference is less than respective thresholds, estimate said ambient temperature as a function of said set of parameters.

5. The control unit (110) as claimed in claim 3 and claim 4, wherein to process said function, said control unit (110) configured to,
calculate of a factor using said first temperature and said second temperature, and
estimate said ambient temperature from a data table (108) corresponding to said factor, wherein said data table (108) is empirically derived relation between said factor and said ambient temperature.

6. A method for estimating an intake air temperature for an engine (120) of a vehicle, said engine (120) coupled with an intake manifold (118) and provided with a temperature sensor (102), said method comprising the steps of:
receiving signals of input variables comprising an engine temperature, an air mass flow through said intake manifold (118) and an ambient temperature, and
determining said intake air temperature using said input variables, characterized by,
determining said intake air temperature through a temperature model (106) derived using regression analysis, said temperature model (106) stored in a memory element (104) of a control unit (110).

7. The method as claimed in claim 6, comprises steps for estimating said ambient temperature using at least one selected from a group comprising a set of parameters, related to said engine temperature, measured and stored in said memory element (104) and a connected device (114), wherein said connected device (114) is at least one of a cluster unit of said vehicle and a communication unit of a user.

8. The method as claimed in claim 7, wherein estimating said ambient temperature, using said set of parameters, comprises the steps of
measuring and storing said set of parameters comprising,
a first temperature at a stop of said engine (120) and a corresponding time of said stop in a previous drive cycle, and
a second temperature at a start of said engine (120) and a corresponding time of said start in a current drive cycle,
calculating a time difference between said start and said stop of said engine (120),
calculating a temperature difference between said first temperature and said second temperature, and
while at least one of said time difference and said temperature difference is less than respective thresholds, estimating said ambient temperature as a function of said set of parameters.

9. A method for estimating ambient temperature for a vehicle, said vehicle comprises a temperature sensor (102) for an engine (120), characterized by, said method comprises the steps of:
measuring and storing in a memory element (104) of a control unit (110), a set of parameters comprising,
a first temperature at a stop of said engine (120) and a corresponding time of said stop in a previous drive cycle,
a second temperature at a start of said engine (120) and corresponding time of said start in a current drive cycle, and
calculating a time difference between said start and said stop of said engine (120),
calculating a temperature difference between said first temperature and said second temperature, and
while at least one of said time difference and said temperature difference is less than respective thresholds, estimating said ambient temperature as a function of said set of parameters.

10. The method as claimed in claim 8 and claim 9, wherein steps of processing said function comprises,
calculating a factor using said first temperature and said second temperature, and
determining said ambient temperature from a data table (108) corresponding to said factor, wherein said data table (108) is empirically derived relation between said factor and said ambient temperature.
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
The present invention relates to control unit to determine ambient air temperature and intake air temperature in a vehicle.

Background of the invention:
In a spark ignition engine, a temperature sensor is present in the inlet manifold to provide the temperature of the incoming air (Intake Air Temperature Sensor- IAT Sensor). This input is utilized in multiple engine functionalities like Fueling, Exhaust Treatment etc.

A patent literature US2002194904 discloses apparatus and method for detecting decrease in air-pressure for use in two-wheeled vehicle, and program for judging decompression for use in two-wheeled vehicle. An apparatus for detecting decrease in air-pressure for use in a two-wheeled vehicle including: a wheel speed detecting means for detecting wheel speeds; an acceleration calculating means for obtaining accelerations of a vehicle body of the two-wheeled vehicle; a slip rate calculating means for calculating slip rates when the acceleration of the vehicle body is in a specified range which is proximate to zero; an average value calculating means for obtaining average values of the slip rates and average vehicle body speeds; a difference calculating means for obtaining differences between the average values of the slip rates and a reference value which is based on an average vehicle body speed as preliminarily set when an internal pressure is normal; and a means for judging decrease in internal pressure. A decrease in air-pressure in a two-wheeled vehicle can be judged so as to enable safe driving.

Brief description of the accompanying drawings:
An embodiment of the disclosure is described with reference to the following accompanying drawing,
Fig. 1 illustrates a block diagram of a control unit to estimate intake air temperature and ambient temperature for a vehicle, according to an embodiment of the present invention, and
Fig. 2 illustrates a method for estimating intake air temperature and ambient temperature for a vehicle, according to the present invention.

Detailed description of the embodiments:
Fig. 1 illustrates a block diagram of a control unit to estimate intake air temperature and ambient temperature for a vehicle, according to an embodiment of the present invention. The control unit 110 to estimate the intake air temperature for an engine 120 of a vehicle is provided. The engine 120 is coupled with an intake manifold 118, and provided with a temperature sensor 102. The intake manifold 118 also comprises throttle body 116. The control unit 110 configured to receive signals for input parameters comprising an engine temperature, an air mass flow through the intake manifold 118 and an ambient temperature, and determine the intake air temperature using the input variables, characterized in that, the intake air temperature is determined through a temperature model 106 derived using regression analysis. The temperature model 106 is stored in a memory element 104 of the control unit 110. The air mass flow is quantity of air flowing into the engine 120 which is calculated either by a conventional air flow sensor or derived using a calibrated look up table based on throttle position and engine speed through respective sensors already existing in the vehicle.

The temperature model 106 is obtained by running a regression analysis on multiple datasets received from multiple test runs of the vehicle under different conditions. The temperature model 106 is provided as,
Intake air temperature = (a)*(engine temperature) + (b)*(air mass flow) + (c)*(engine temperature – ambient temperature) …... (1)
where, a, b, c – calibratable variables and coefficients obtained by the regression analysis.

In accordance to an embodiment of the present invention, the ambient temperature is determined using at least one selected from a group comprising a set of parameters, related to said engine temperature, measured and stored in the memory element 104 and a connected device 114. The connected device 114 is at least one of a cluster unit (connected instrument cluster) of the vehicle and a communication unit of a user. The user is rider or driver of the vehicle.

In accordance to an embodiment of the present invention, to determine the ambient temperature using the set of parameters, the control unit 110 is configured to measure and store the set of parameters which comprises a first temperature at a stop of the engine 120 and corresponding time of stop in a previous drive cycle and a second temperature at a start of the engine 120 and corresponding time of start in a current drive cycle. The stop time is measured during the end of the drive cycle and start time is measured during beginning of new drive cycle. The set of parameters has an influence on the determination of the ambient temperature. The control unit 110 calculates a time difference between the start and the stop of the engine 120 and also calculates a temperature difference between the first temperature and the second temperature. While at least one of the time difference and the temperature difference is less than respective thresholds, that the control unit 110 estimates the ambient temperature as a function of the set of parameters.

If any one of the temperature difference and the time differences exceeds respective threshold value, i.e. a temperature threshold and time threshold, then the second temperature (i.e. engine start temperature) is set as the ambient temperature. The reason for setting the second temperature as the ambient temperature is that the vehicle as undergone enough/sufficient cooling between the stop of the engine 120 and start of the engine 120. Due to sufficient cooling, the engine 120 attains the ambient temperature.

In accordance to an embodiment of the present invention, the control unit 110 is configured to determine ambient temperature from the connected device 114. Consider the connected device 114 is the cluster unit of the vehicle and the user of the vehicle carries the communication unit, such as a smartphone, a wearable device such as smartwatch, etc. The control unit 110 acquires the ambient temperature from the cluster unit which is connected to a cloud 112 or server. Alternatively, the cluster unit acquires the ambient temperature information from the communication unit of the user. The communication unit is connected to the cluster unit through wireless or wired means such as Bluetooth™, Universal Serial Bus (USB) cables, Infra-Red, Type-C cables, etc., and itself connected to the cloud 112 through internet connectivity. The connection to the cloud 112 or the communication unit gives the control unit 110 access to the location and along with that the ambient temperature in that region at that time. Further, even if there is a connectivity loss, the control unit 110 considers last recorded input.

In accordance to an embodiment of the present invention, the control unit 110 is provided to estimate ambient temperature for the vehicle. The vehicle comprises the temperature sensor 102 for the engine 120, characterized in that, the control unit 110 configured to measure and store the set of parameters comprising, the first temperature at the stop of the engine 120 and the corresponding time of the stop, in the previous drive cycle, and the second temperature at the start of the engine 120 and the corresponding time of the start in the current drive cycle. The control unit 110 calculates the time difference between the start and the stop of the engine 120. The control unit 110 also calculates the temperature difference between the first temperature and the second temperature. While at least one of the time difference and the temperature difference is less than respective thresholds, the control unit 110 estimates the ambient temperature as the function of the set of parameters.

If any one of the temperature difference and the time difference exceeds respective threshold value, i.e. the temperature threshold and the time threshold, then the second temperature is set as the ambient temperature. The reason for setting the second temperature as the ambient temperature is that the vehicle as undergone enough/sufficient cooling between the stop of the engine 120 and start of the engine 120. Due to sufficient cooling, the engine 120 attains the ambient temperature.

In accordance to an embodiment of the present invention, the control unit 110 processes the function to estimate the ambient temperature. To process the function, the control unit 110 configured to calculate a factor using the first temperature and the second temperature, and estimates the ambient temperature from a data table 108 (or data map) corresponding to the factor. The data table 108 is empirically derived relation between the factor and the ambient temperature. The data table 108 may also be referred to as a curve.

The factor corresponds to ratio of second temperature and the first temperature. Alternatively, the factor is a dependent on the ratio as below
factor=mod((ratio -1 )/(time difference)) ………... (2)
Further, the data table 108 comprises relation between the factor or inverse of the factor and corresponding ambient temperature. The Newton’s law of cooling is used as the basis for deriving the factor and the data table 108.
T(t)=T_a+(T_0-T_a)e^(-kt) …………… (3)
where,
Ta is the ambient temperature (which is to be determined)
To is the first temperature (also known as start temperature of the engine 120)
T(t) is second temperature (also known as stop temperature of the engine 120)
t is the time between first temperature and the second temperature
k is the cooling rate and is dependent on the ambient temperature

According to the present invention, a working of the control unit 110 is described with multiple scenarios and assumptions. Consider the temperature threshold is 50 degrees Celsius (deg C) and time threshold is 18,000 seconds. The data table 108 is already stored in the memory element 104 as below. The below data table 108 is only an example and is not to be understood in limiting manner.
1/factor 2000 2300 2600 2900 3400
Ambient temperature (in degree Celsius) 0 10 25 35 45

In a first scenario the first temperature is 70 deg C and second temperature is 50 deg C. Assuming the time difference is 30 minutes, i.e. 1800 seconds, the inverse of the factor based on equation (2) is found to be 2525. The closest ambient temperature from the above table is 25. This ambient temperature is then taken to calculate intake air temperature as per equation (1).

In a second scenario the first temperature is 100 deg C and second temperature is 45 deg C. Assume the time difference is 360 minutes, i.e. 21600 seconds. Since the time difference is greater than 18,000 seconds, the ambient temperature is set as 45 deg C. This ambient temperature is then taken to calculate intake air temperature as per equation (1).

In a third scenario the first temperature is 80 deg C and second temperature is 20 deg C. Assume the time difference is 240 minutes, i.e. 14400 seconds. Since the temperature difference is greater than 50 deg C, the ambient temperature is set as 20 deg C. This ambient temperature is then taken to calculate intake air temperature as per equation (1).

The control unit 110 refers to computing devices/units comprising components such as memory element 104 such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC), Digital-to-Analog Convertor (DAC), clocks, timers and a processor (such as Central Processing Unit (CPU)) (capable of implementing machine learning) connected with the each other and to other components through communication bus channels. The components mentioned are just for understanding and may have more or less components as per requirement. The memory element 104 of the control unit 110 is prestored with logics or instructions or programs or applications or thresholds or values which is accessed by the processor as per the defined routines. The internal components of the control unit 110 are not explained for being state of the art, and the same must not be understood in a limiting manner. The control unit 110 is capable to communicate through wired and wireless means such as but not limited to Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks, Universal Serial Bus (USB) cable, micro-USB, and the like.

In accordance to an embodiment of the present invention, the control unit 110 is possible to be an Engine Management System Electronic Control Unit (EMS ECU) or another controller interfaced with the EMS ECU. The control unit 110 is also possible to be at least one of the connected device 114 and the cloud 112. Also, the vehicle is any one of a two wheeler such as motorcycles or scooters, a three wheelers such as auto-rickshaws, four wheelers such as cars, snow mobiles or power sport vehicles or other vehicles with internal combustion engines 120.

Fig. 2 illustrates a method for estimating intake air temperature and ambient temperature for a vehicle, according to the present invention. At first, a method for estimating the intake air temperature for the engine 120 of the vehicle is disclosed. The engine 120 is coupled with the intake manifold 118 and provided with the temperature sensor 102 for measurement of temperature. The intake manifold 118 also comprises throttle body 116. The method comprises plurality of steps, of which a step 202 comprises receiving signals of input variables comprising the engine temperature, the air mass flow through the intake manifold 118 and the ambient temperature. A step 204 comprises determining the intake air temperature using the measured input variables. The step 204 is characterized by, determining the intake air temperature through the temperature model 106 derived using regression analysis. The temperature model 106 is stored in the memory element 104 of the control unit 110. The method is executed by the control unit 110.

According to the present invention, the method comprises steps for determining the ambient temperature using at least one selected from the group comprising a set of parameters, related to the engine temperature, measured and stored in the memory element 104, and the connected device 114. The connected device 114 is at least one of the cluster unit of the vehicle and the communication unit of the user. The steps for estimating the ambient temperature using the set of parameters is represented by numeral 200 and comprises plurality of steps, of which a step 206 comprises measuring and storing the set of parameters comprising, the first temperature at the stop of the engine 120 and the corresponding time of the stop in the previous drive cycle, and the second temperature at the start of the engine 120 and the corresponding time of the start in the current drive cycle. A step 208 comprises calculating the time difference between the start and the stop of the engine 120. A step 210 comprises calculating the temperature difference between the first temperature and the second temperature. A step 212 is a conditional execution according to which, while at least one of the time difference and the temperature difference is less than respective thresholds, the step 212 proceeds with estimating the ambient temperature as the function of the set of parameters.

If any one of the temperature difference and the time difference exceeds respective threshold value, i.e. the temperature threshold and the time threshold, then the step 212 comprises setting the second temperature is set as the ambient temperature. The reason for setting the second temperature as the ambient temperature is that the vehicle as undergone enough/sufficient cooling between the stop of the engine 120 and start of the engine 120. Due to sufficient cooling, the engine 120 attains the ambient temperature.

According to the present invention, the method for estimating ambient temperature in the vehicle is disclosed and is referenced with the numeral 200. The vehicle comprises the temperature sensor 102 for the engine 120. The method is characterized by plurality of steps of which a step 206 comprises, measuring and storing in the memory element 104 of the control unit 110, the set of parameters comprising, the first temperature at the stop of the engine 120 and the corresponding time of the stop in the previous drive cycle, and the second temperature at the start of the engine 120 and the corresponding time of the start in the current drive cycle. A step 208 comprises calculating the time difference between the start and the stop of the engine 120. A step 210 comprises calculating the temperature difference between the first temperature and the second temperature. A step 212 is a conditional statement according to which, while at least one of the time difference and the temperature difference is less than respective thresholds, the step 212 (or method) proceeds with estimating the ambient temperature as the function of the set of parameters. If any one of the temperature difference and the time difference exceeds respective threshold value, i.e. the temperature threshold and the time threshold, then the step 212 comprises setting the second temperature is set as the ambient temperature. The reason for setting the second temperature as the ambient temperature is that the vehicle as undergone enough/sufficient cooling between the stop of the engine 120 and start of the engine 120. Due to sufficient cooling, the engine 120 attains the ambient temperature.

According to the present invention, the control unit 110 processes the function to estimate the ambient temperature. The control unit 110 configured to calculate the factor using the first temperature and the second temperature, and estimates the ambient temperature from the data table 108 corresponding to the factor. The data table 108 is empirically derived relation between the factor and the ambient temperature. The data table 108 may also be referred to as the curve. The above described equations (1) and (2), scenarios are to be referred for understanding the method and a repetition is avoided. The same must not be understood in limiting manner.

In accordance to an embodiment of the present invention, the core of the control unit 110 is to replace a dedicated intake air temperature sensor with a regression based temperature model 106 and taking, the engine temperature, air mass flow and ambient temperature as input parameters. The temperature model 106 estimates the intake temperature with accuracy and is passed on to other functions of the EMS of the vehicle. The present invention offers simplified solution by eliminating the dedicated intake air temperature sensor and replacing with regression based temperature model 106 while meeting all the market and legal requirements. An intake air temperature estimation by the regression model is disclosed.

It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.