Claims:CLAIMS
We claim,
1. A method for determining a motoring loss in an engine of a vehicle using a chassis dynamometer, said method comprising:
mounting the vehicle on the chassis dynamometer;
setting the engine of the vehicle in a non-firing state;
setting a power transmission unit of the vehicle in a neutral position; driving at least one wheel of the vehicle that is operatively connected to the engine through at least one roller of the chassis dynamometer;
setting the power transmission unit of the vehicle in a gear position having a transmission ratio value equal or close to 1;
engaging the power transmission unit to the engine by engaging a clutch of the vehicle;
driving the roller of the chassis dynamometer at a predetermined speed;
measuring a load provided by the engine and a drive train of the vehicle through a load sensor of the chassis dynamometer for determining a power loss in driving the engine and the drive train of the vehicle through a control unit of the chassis dynamometer;
disengaging the power transmission unit from the engine by disengaging the clutch;
measuring a load provided by the drive train of the vehicle through the load sensor for determining a power loss in driving the drive train of the vehicle through the control unit; and
determining the motoring loss in the engine based on the difference between, the power loss in driving the engine and the drive train of the vehicle and the power loss in driving the drive train of the vehicle through the control unit.
2. The method as claimed in claim 1, wherein said step of setting the engine of the vehicle in the non-firing state includes switching off an ignition system of the engine.
3. The method as claimed in claim 1 further comprises a step of warming up the vehicle.
4. A method for determining a friction loss in an engine of a vehicle using a chassis dynamometer, said method comprising:
mounting the vehicle on the chassis dynamometer;
mounting a pressure sensor of the chassis dynamometer in the engine;
setting the engine of the vehicle in a non-firing state;
setting a power transmission unit of the vehicle in a neutral position;
driving at least one wheel of the vehicle that is operatively connected to the engine through at least one roller of the chassis dynamometer;
setting the power transmission unit of the vehicle in a gear position having a transmission ratio value equal or close to 1;
engaging the power transmission unit to the engine by engaging a clutch of the vehicle;
driving the roller of the chassis dynamometer at a predetermined speed;
measuring a load provided by the engine and a drive train of the vehicle through a load sensor of the chassis dynamometer for determining a power loss in driving the engine and the drive train of the vehicle through a control unit of the chassis dynamometer;
measuring a pressure inside at least one cylinder in the engine through a pressure sensor of the chassis dynamometer for determining a pumping loss in the engine through the control unit;
disengaging the power transmission unit from the engine by disengaging the clutch;
measuring a load provided by the drive train of the vehicle through the load sensor for determining a power loss in driving the drive train of the vehicle through the control unit;
determining the motoring loss in the engine based on the difference between, the power loss in driving the engine and the drive train of the vehicle and the power loss in driving the drive train of the vehicle through the control unit; and
determining the friction loss in the engine based on the difference between the motoring loss and the pumping loss in the engine through the control unit.
5. The method as claimed in claim 4, wherein said step of setting the engine of the vehicle in the non-firing state includes switching off an ignition system of the engine.
6. The method as claimed in claim 4, further comprises a step of warming up the vehicle.
7. A chassis dynamometer comprising:
at least one roller adapted for driving at least one wheel of a vehicle;
an electric motor connected to said roller, said electric motor adapted for driving said roller;
at least one load sensor adapted for determining a load provided by an engine and/or drive train of the vehicle;
at least one pressure sensor adapted for determining a pressure inside at least one cylinder in the engine of the vehicle; and
a control unit adapted for determining a friction loss in the engine,
wherein
said load sensor and said pressure sensor is provided in communication with said control unit; and
said control unit determines the friction loss in the engine based on a motoring loss and a pumping loss in the engine, the motoring loss in the engine is determined by said control unit based on the power loss in driving the engine and drive train of the vehicle and the power loss in driving the drive train of the vehicle, wherein the power loss in driving the engine and drive train of the vehicle and the power loss in driving the drive train of the vehicle is determined by said control unit based on the input provided by said load sensor and the pumping loss in the engine is determined by said control unit based on the input provided by said pressure sensor.

Dated this 31st July 2015
Signature:

Name: Kalyan Chakravarthy
, Description:FORM 2
The Patent Act 1970
(39 of 1970)
&
The Patent Rules, 2005

COMPLETE SPECIFICATION
(SEE SECTION 10 AND RULE 13)

TITLE OF THE INVENTION

“A CHASSIS DYNAMOMETER AND A METHOD FOR TESTING AN ENGINE OF A VEHICLE”

APPLICANT:

Name Nationality Address
Mahindra & Mahindra Limited Indian Mahindra & Mahindra Ltd.,
MRV, Mahindra World City (MWC),
Plot No. 41/1, Anjur Post, Chengalpattu,
Kanchipuram District – 603204 (TN) INDIA

The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

TECHNICAL FIELD
[001] The embodiments herein generally relate to engine testing in vehicles and more particularly but not exclusively to engine testing in vehicles using chassis dynamometer.

BACKGROUND
[002] Generally, an engine of a vehicle is tested using an engine dynamometer for determining the emission values, durability, motoring loss, friction loss, pumping loss of an engine etc. Testing a vehicle’s engine through an engine dynamometer is a time consuming process as the engine needs to be dismantled from the vehicle and mounted on to the test bed of engine dynamometer for testing the engine. Further, the testing involves the replication of wiring harness setup in test bed of the engine dyanamometer and emulation of requisite sensor signals necessary for proper operation of the electronic control unit (ECU) of the engine. Hence, the original setting of the engine invariably gets disturbed in the process and the vehicle is rendered unusable during the testing period.
[003] Therefore, there exists a need for a simple method for testing the engine of a vehicle for determining motoring loss and friction loss in the engine. Furthermore, there exists a need for a method that eliminates the aforementioned drawbacks.

OBJECTS
[004] The principle object of an embodiment of this invention is to provide a simple method for testing an engine of a vehicle using a chassis dynamometer for determining the motoring loss in the engine.
[005] Another object of an embodiment of this invention is to provide a simple method for testing an engine of a vehicle using a chassis dynamometer for determining the friction loss in the engine.
[006] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF DRAWINGS
[007] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[008] FIG. 1 depicts a schematic of the chassis dynamometer according to an embodiment of the invention as disclosed herein;
[009] FIG. 2a depicts a vehicle mounted to the chassis dynamometer with the engine engaged to the power transmission unit of the vehicle according to an embodiment of the invention as disclosed herein;
[0010] FIG. 2b depicts a vehicle mounted to the chassis dynamometer with the engine disengaged from the power transmission unit of the vehicle according to an embodiment of the invention as disclosed herein;
[0011] FIG. 3 depicts a flow chart of the method for determining the motoring loss in the engine according to an embodiment of the invention as disclosed herein;
[0012] FIG. 4 depicts a flow chart of the method for determining the friction loss in the engine according to an embodiment of the invention as disclosed herein; and
[0013] FIG. 5 depicts a graph showing the correlation between engine motoring loss values measured using an engine dynamometer and the chassis dynamometer according to an embodiment of the invention as disclosed herein.

DETAILED DESCRIPTION
[0014] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0015] The embodiments herein achieve a simple method for testing an engine of a vehicle using a chassis dynamometer for determining the motoring loss in the engine. Further, embodiments herein achieve a method for testing an engine of a vehicle using a chassis dynamometer for determining the friction loss in the engine. Referring now to the drawings, and more particularly to FIGS. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0016] FIG. 1 depicts a schematic of the chassis dynamometer according to an embodiment of the invention as disclosed herein. The chassis dynamometer 100 includes, at least one roller 102, an electric motor/generator 104, at least one load sensor 106, a control unit 108, at least one pressure sensor (not shown), a power supply (not shown) and a frame (not shown).
[0017] In an embodiment a vehicle 200 to be tested includes at least one wheel 202, at least one engine 204, at least one clutch 206, at least one power transmission unit 208, at least one propeller shaft (not shown), a wheel axle (not shown) and a differential (not shown). In an embodiment the clutch 206, power transmission unit 208, propeller shaft, wheel axle and the differential constitute the drive train (not shown) of the vehicle. However, it is also within the scope of the invention that drive train (not shown) of the vehicle 200 may include any other components without otherwise deterring the intended function of the drive train (not shown) as can be deduced from the description. In an embodiment the drive train (not shown) is used for delivering the power from the engine 204 to the wheels 202 of the vehicle 200 for propulsion. In an embodiment the power transmission unit 208 includes a plurality of gears (not shown) actuated by a gear selecting lever (not shown) to offer different speed ratios. In an embodiment the vehicle 200 to be tested is a four wheeled vehicle. However, it is also within the scope of the invention to test two wheeled vehicles or vehicles with any number of wheels without otherwise deterring the intended function of the chassis dynamometer 100.
[0018] In an embodiment the roller 102 is used for driving the wheels 202 of a vehicle 200. The roller 102 is driven by the electric motor/generator 104 for driving the wheels 202 of the vehicle 200. In an embodiment the chassis dynamometer includes two rollers 102 (one for driving left wheel and one for driving right wheel). However, it is also within the scope of the invention to provide any number of rollers 102 without otherwise deterring the intended function of the roller 102 as can be deduced from the description. In an embodiment the load sensor 106 is connected with a housing (not shown) of the electric motor/generator 104 for measuring the load/torque provided by the engine and/or drive train of the vehicle. In an embodiment the load sensor 106 is a load cell. However, it is also within the scope of the invention to provide any other type of load sensor 106 without otherwise deterring the intended function of the load sensor 106 as can be deduced from the description.
[0019] In an embodiment the control unit 108 includes a display unit (not shown), at least one control switch (not shown) for setting the chassis dynamometer 100 in motoring/driving mode, at least one control switch (not shown) for setting the speed of the roller 102. In an embodiment the control unit 108 is provided in communication with the load sensor 106 for determining the motoring loss and friction loss in the engine 204 of the vehicle 200. In an embodiment, the control unit 108 described herein can include for example, but not limited to, microprocessor, microcontroller, controller, smart phone, portable electronic device, communicator, tablet, laptop, computer, consumer electronic device, a combination thereof, or any other device capable of processing signals.
[0020] In an embodiment the control unit 108 determines the motoring loss (measured in Kilowatt) in the engine 204 based on the following equation,
Motoring loss (Mp) = P1 – P2,
where,
P1 = Power loss in driving the engine and drive train of the vehicle in Kilowatt
P2 = Power loss in driving the drive train of the vehicle in Kilowatt
[0021] In an embodiment the P1 and P2 are determined by the control unit 108 based on the following equations,
P1 = 2 * p * N*T1
------------------
60000
P2 = 2 * p * N*T2
------------------
60000
where,
T1 = Load provided by the engine and drive train of the vehicle in Newton-metre
T2 = Load provided by the drive train of the vehicle in Newton-metre
N = Engine speed in revolution per minute
[0022] In an embodiment engine speed N is determined using the below equation,
N 1000 * GR * FDR
--- = ------------------------
V 2 * p * 60 * r
where,
V = Vehicle velocity (predetermined speed of the roller) in kilometer per hour
r = Tyre dynamic rolling radius in metre
GR = Gear ratio (based on the gear position set in the power transmission unit 208)
FDR = Final drive ratio of the power transmission unit 208
[0023] In an embodiment the pumping loss (measured in Newton metre) in the engine 204 is measured using the formula,
Pumping loss = PMEP * Vd
where,

where,
PMEP = Pumping mean effective pressure in Newton per metre square.
Pcyl = In-cylinder pressure (measured using the pressure sensor) in Newton per metre square
Vd = Displacement volume of the engine in cubic metre
aI and aII = Crank angle in degree
[0024] The values of aI and aII are selected based on the intake stroke and exhaust stroke of the engine 204. In an embodiment aI is 180 degree and aII is 540 degree. However, it is also within the scope of the invention to use any other values for aI and aII based on the intake and exhaust stroke of the engine 204.
[0025] In an embodiment the crank angles for various strokes of the engine 204 are as follows,
Crank angle 0 to 180 degree Power stroke
Crank angle 180 to 360 degree Exhaust stroke
Crank angle 360 to 540 degree Intake stroke
Crank angle 540 to 720 degree Compression stroke

[0026] In an embodiment the friction loss in (measured in Newton metre) the engine is measured using the formula,
Friction loss = Motoring loss – Pumping loss
[0027] However, as the motoring loss and pumping loss are measured in different units in order to determine the friction loss, the motoring loss (in Kilowatt) is converted/measured in terms of torque (Newton-metre) using the below formula and thereafter Friction loss is determined in Newton-metre.
Mp * 60000
(Mt) = -----------------
2 * p * N
where,
Mt = Motoring loss measured in terms of torque Newton-metre
Mp = Motoring loss in Kilowatt
N = Engine speed in revolution per minute
[0028] Similarly in order to measure the friction loss in terms of Kilowatt the pumping loss is converted/measured in terms of Kilowatt using the formula,
2 * p * N*T
P = ------------------
60000
where,
P = pumping loss in Kilowatt
T = pumping loss measured in Newton-metre
N = Engine speed in revolution per minute
[0029] Thus as the motoring loss and pumping loss are measured in Kilowatt, the friction loss can also measured in terms of Kilowatt.
[0030] In an embodiment the pressure sensor (not shown) is used for measuring a pressure inside at least one cylinder (not shown) in the engine 204 for determining a pumping loss in the engine 204. The pressure sensor (not shown) is provided in communication with the control unit 108. The pressure sensor (not shown) provides input to the control unit 108 for determining the pumping loss in the engine 204. In an embodiment the pressure sensor (not shown) is provided at the place (not shown) of glowplug/sparkplug (not shown) in the engine 204 for measuring the pressure in the cylinder (not shown) of the engine 204. However, it is also within the scope of the invention to provide the pressure sensor (not shown) at any other location in the engine 204 without otherwise deterring the intended function of the pressure sensor as can be deduced from the description. In an embodiment the power supply (not shown) is used for powering the electric motor/generator 104 and the control unit 108. In an embodiment the frame (not shown) is used for mounting the vehicle 200 over the chassis dynamometer 100 for testing the engine 204.
[0031] FIG. 3 depicts a flow chart of the method for determining the motoring loss in the engine according to an embodiment of the invention as disclosed herein. The method 300 for testing an engine of a vehicle using a chassis dynamometer for determining a motoring loss in the engine includes, mounting the vehicle on the chassis dynamometer step 301, warming up the vehicle step 302, setting the engine of the vehicle in a non-firing state step 303, setting a power transmission unit of the vehicle in a neutral position step 304, driving at least one wheel of the vehicle that is operatively connected to the engine through at least one roller of the chassis dynamometer step 305, setting the power transmission unit of the vehicle in a gear position having a transmission ratio value equal or close to 1 step 306, engaging the power transmission unit to the engine by engaging a clutch of the vehicle step 307, driving the roller of the chassis dynamometer at a predetermined speed step 308, measuring a load provided by the engine and a drive train of the vehicle through a load sensor of the chassis dynamometer for determining a power loss in driving the engine and the drive train of the vehicle through a control unit of the chassis dynamometer step 309, disengaging the power transmission unit from the engine by disengaging the clutch step 310, measuring a load provided by the drive train of the vehicle through the load sensor for determining a power loss in driving the drive train of the vehicle through the control unit step 311 and determining the motoring loss in the engine based on the difference between, the power loss in driving the engine and the drive train of the vehicle and the power loss in driving the drive train of the vehicle through the control unit step 312.
[0032] The working of the chassis dynamometer 100 in conjunction with the method 300 for determining the motoring loss is as follows. FIG. 2a depicts a vehicle mounted to the chassis dynamometer with the engine engaged to the power transmission unit of the vehicle according to an embodiment of the invention as disclosed herein. FIG. 2b depicts a vehicle mounted to the chassis dynamometer with the engine disengaged from the power transmission unit of the vehicle according to an embodiment of the invention as disclosed herein.
[0033] First the vehicle 200 is mounted on the chassis dynamometer 100 and the vehicle 200 is warmed up. Then the engine 204 is set in non-firing state by switching off an ignition system (not shown) of the engine 204. Based on the type of vehicle 200 the appropriate wheels 202 of the vehicle 200 are provided in contact with the rollers 102. For example if the vehicle 200 to be tested is a rear wheel drive vehicle the rear wheels of the vehicle 200 are provided in contact with the rollers 102. The vehicle’s power transmission unit 208 is set to neutral position and the chassis dynamometer 100 is set to motoring/driving mode through the control unit 108. Thereafter, the rollers 102 of the chassis dynamometer 100 starts driving the appropriate wheels 202 of the vehicle 200 at a minimum speed. Thereafter the power transmission unit 208 is set to a gear position having transmission ratio equal or close to 1 from the neutral position. In an embodiment the gear position having transmission ratio value equal or close to 1 is a top gear position in the power transmission unit 208 (4th or 5th gear) that is equal or near to direct drive speed. Then the power transmission unit 208 is engaged to the engine 204 as shown in Fig. 2a. In an embodiment engaging the power transmission unit 208 to the engine 204 is done using the clutch 206. In an embodiment the clutch 206 is disengaged by depressing the clutch pedal (not shown) and the required gear position in the power transmission unit 208 is selected and the clutch 206 is engaged by gradually releasing the clutch pedal (not shown) for engaging the power transmission unit 208 to the engine. However it is also within the scope of the invention to engage and disengage the clutch 206 without using clutch pedal (not shown). As the wheels 202 of the vehicle 200 are driven by the rollers 102 of the chassis dynamometer 100 the drive train (wheel axle, the differential, the propeller shaft, the power transmission unit 208, the clutch 206) and the components of the engine 204 such as crankshaft (not shown), camshaft (not shown), pistons (not shown), valves (not shown) etc., are driven as the power transmission unit 208 is engaged to the engine 204. Thereafter the rollers 102 of the chassis dynamometer 100 are driven at a predetermined speed. In an embodiment the predetermined speed is based on the low idle governing speed and maximum speed of the set gear position of the power transmission unit 208 i.e the predetermined speed values shall be selected between the low idle governing speed and maximum vehicle speed of the gear position selected in the power transmission unit during testing. Now the rollers 102 of the chassis dynamometer 100 rotates at the predetermined speed and the load provided by the engine 204 and the drive train of the vehicle 200 is measured using the load sensor 106. Based on the input provided by the load sensor 106 the control unit 108 determines the power loss in driving the engine 204 and drive train of the vehicle 200. Thereafter the clutch 206 is disengaged and the power transmission unit 208 is disengaged from the engine 204 as shown in Fig. 2b. As the power transmission unit 208 is disengaged from the engine 204 only the drive train of the vehicle 200 is driven by the rollers 102 of the chassis dynamometer 100 and the load provided by the drive train (not shown) of the vehicle 200 is measured using the load sensor 106. Based on the input provided by the load sensor 106 the control unit 108 determines the power loss in driving the drive train of the vehicle 200. Based on the difference between, the power loss in driving the engine and drive train of the vehicle 200 and the power loss in driving the drive train of the vehicle 200 the motoring loss in the engine 204 is determined by the control unit 108 of the chassis dynamometer 100.
[0034] FIG. 4 depicts a flow chart of the method for determining the friction loss in the engine according to an embodiment of the invention as disclosed herein. The method 400 for testing an engine of a vehicle using a chassis dynamometer for determining a friction loss in the engine includes, mounting the vehicle on the chassis dynamometer step 401, warming up the vehicle step 402, setting the engine of the vehicle in a non-firing state step 403, mounting a pressure sensor of the chassis dynamometer in the engine 404, setting a power transmission unit of the vehicle in a neutral position step 405, driving at least one wheel of the vehicle that is operatively connected to the engine through at least one roller of the chassis dynamometer step 406, setting the power transmission unit of the vehicle in a gear position having a transmission ratio value equal or close to 1 step 407, engaging the power transmission unit to the engine by engaging a clutch of the vehicle step 408, driving the roller of the chassis dynamometer at a predetermined speed step 409, measuring a load provided by the engine and a drive train of the vehicle through a load sensor of the chassis dynamometer for determining a power loss in driving the engine and the drive train of the vehicle through a control unit of the chassis dynamometer step 410, measuring a pressure inside at least one cylinder in the engine through a pressure sensor of the chassis dynamometer for determining a pumping loss in the engine through the control unit step 411, disengaging the power transmission unit from the engine by disengaging the clutch step 412, measuring a load provided by the drive train of the vehicle through the load sensor for determining a power loss in driving the drive train of the vehicle through the control unit step 413, determining the motoring loss in the engine based on the difference between, the power loss in driving the engine and the drive train of the vehicle and the power loss in driving the drive train of the vehicle through the control unit step 414 and determining the friction loss in the engine based on the difference between the motoring loss and the pumping loss in the engine through the control unit step 415.
[0035] The working of the chassis dynamometer 100 in conjunction with the method 400 for determining the friction loss is as follows. First the vehicle 200 is mounted on the chassis dynamometer 100 and the vehicle 200 is warmed up. Then the engine 204 is set in non-firing state by switching off an ignition system (not shown) of the engine 204. Thereafter, the pressure sensor (not shown) of the chassis dynamometer 100 is mounted in the engine. Based on the type of vehicle the appropriate wheels 202 of the vehicle 200 are provided in contact with the rollers 102. For example if the vehicle to be tested is a rear wheel drive vehicle the rear wheels of the vehicle 200 are provided in contact with the rollers 102. The vehicle’s power transmission unit 208 is set to neutral position and the chassis dynamometer 100 is set to motoring/driving mode through the control unit 108. Thereafter, the rollers 102 of the chassis dynamometer 100 starts driving the appropriate wheels 202 of the vehicle 200 at a minimum speed. Thereafter the power transmission unit 208 is set to a gear position having transmission ratio value equal or close to 1 from the neutral position. In an embodiment the gear position having transmission ratio value equal or close to 1 is a top gear position in the power transmission unit 208 (4th or 5th gear) that is equal or near to direct drive speed. Then the power transmission unit 208 is engaged to the engine 204 as shown in Fig. 2a. In an embodiment engaging the power transmission unit 208 to the engine 204 is done using the clutch 206. First the clutch 206 is disengaged by depressing the clutch pedal (not shown) and the required gear position in the power transmission unit 208 is selected and the clutch 206 is engaged by gradually releasing the clutch pedal (not shown) for engaging the power transmission unit 208 to the engine. However it is also within the scope of the invention to engage and disengage the clutch 206 without using clutch pedal (not shown). As the wheels 202 of the vehicle 200 are driven by the rollers 102 of the chassis dynamometer 100 the drive train (wheel axle, the differential, the propeller shaft, the power transmission unit 208, the clutch 206) and the components of the engine 204 such as crankshaft (not shown), camshaft (not shown), pistons (not shown), valves (not shown) etc., are driven as the power transmission unit 208 is engaged to the engine 204. Thereafter the rollers 102 of the chassis dynamometer 100 are driven at a predetermined speed. In an embodiment the predetermined speed is based on the low idle governing speed and maximum speed of the set gear position of the power transmission unit 208 i.e the predetermined speed values shall be selected between the low idle governing speed and maximum vehicle speed of the gear position selected in the power transmission unit during testing. Now the rollers 102 of the chassis dynamometer 100 rotates at the predetermined speed and the load provided by the engine 204 and the drive train (not shown) of the vehicle 200 is measured using the load sensor 106. Based on the input provided by the load sensor 106 the control unit 108 determines the power loss in driving the engine 204 and the drive train (not shown) of the vehicle 200. Next the pressure inside at least one cylinder (not shown) in the engine 204 is measured using the pressure sensor (not shown) for determining the pumping loss in the engine 204 by the control unit 108. Thereafter the clutch 206 is disengaged and the power transmission unit 208 is disengaged from the engine 204 as shown in Fig. 2b. As the power transmission unit 208 is disengaged from the engine 204 only the drive train of the vehicle 200 is driven by the rollers 102 of the chassis dynamometer 100 and the load provided by the drive train (not shown) of the vehicle 200 is measured using the load sensor 106. Based on the input provided by the load sensor 106 the control unit 108 determines the power loss in driving the drive train of the vehicle 200. Based on the difference between, the power loss in driving the engine 204 and the drive train of the vehicle 200 and the power loss in driving the drive train (not shown) of the vehicle 200 the motoring loss is determined by the control unit 108 of the chassis dynamometer 100. Based on the difference in the values between the motoring loss and the pumping loss, the friction loss is determined by the control unit 108 of the chassis dynamometer 100.
[0036] FIG. 5 depicts a graph showing the correlation between engine motoring loss values measured using an engine dynamometer and the chassis dynamometer according to an embodiment of the invention as disclosed herein. The graph depicts the motoring loss measured using the chassis dynamometer 100 and the motoring loss measured using an engine dynamometer (not shown). The motoring loss measured using the chassis dynamometer 100 through the method 300 correlates with the motoring loss measured using the engine dynamometer by 97%. Thus a simple method for testing an engine 204 of the vehicle 200 using the chassis dynamometer 100 for determining the motoring loss is provided.
[0037] The various actions, units, steps, blocks, or acts described in the method 300 and 400 can be performed in the order presented, in a different order, simultaneously, or a combination thereof. Further, in some embodiments, some of the actions, units, steps, blocks, or acts listed in the FIG. 4 and FIG. 5 may be omitted, added, skipped, or modified without departing from the scope of the invention.
[0038] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

CLAIMS
We claim,
1. A method for determining a motoring loss in an engine of a vehicle using a chassis dynamometer, said method comprising:
mounting the vehicle on the chassis dynamometer;
setting the engine of the vehicle in a non-firing state;
setting a power transmission unit of the vehicle in a neutral position; driving at least one wheel of the vehicle that is operatively connected to the engine through at least one roller of the chassis dynamometer;
setting the power transmission unit of the vehicle in a gear position having a transmission ratio value equal or close to 1;
engaging the power transmission unit to the engine by engaging a clutch of the vehicle;
driving the roller of the chassis dynamometer at a predetermined speed;
measuring a load provided by the engine and a drive train of the vehicle through a load sensor of the chassis dynamometer for determining a power loss in driving the engine and the drive train of the vehicle through a control unit of the chassis dynamometer;
disengaging the power transmission unit from the engine by disengaging the clutch;
measuring a load provided by the drive train of the vehicle through the load sensor for determining a power loss in driving the drive train of the vehicle through the control unit; and
determining the motoring loss in the engine based on the difference between, the power loss in driving the engine and the drive train of the vehicle and the power loss in driving the drive train of the vehicle through the control unit.
2. The method as claimed in claim 1, wherein said step of setting the engine of the vehicle in the non-firing state includes switching off an ignition system of the engine.
3. The method as claimed in claim 1 further comprises a step of warming up the vehicle.
4. A method for determining a friction loss in an engine of a vehicle using a chassis dynamometer, said method comprising:
mounting the vehicle on the chassis dynamometer;
mounting a pressure sensor of the chassis dynamometer in the engine;
setting the engine of the vehicle in a non-firing state;
setting a power transmission unit of the vehicle in a neutral position;
driving at least one wheel of the vehicle that is operatively connected to the engine through at least one roller of the chassis dynamometer;
setting the power transmission unit of the vehicle in a gear position having a transmission ratio value equal or close to 1;
engaging the power transmission unit to the engine by engaging a clutch of the vehicle;
driving the roller of the chassis dynamometer at a predetermined speed;
measuring a load provided by the engine and a drive train of the vehicle through a load sensor of the chassis dynamometer for determining a power loss in driving the engine and the drive train of the vehicle through a control unit of the chassis dynamometer;
measuring a pressure inside at least one cylinder in the engine through a pressure sensor of the chassis dynamometer for determining a pumping loss in the engine through the control unit;
disengaging the power transmission unit from the engine by disengaging the clutch;
measuring a load provided by the drive train of the vehicle through the load sensor for determining a power loss in driving the drive train of the vehicle through the control unit;
determining the motoring loss in the engine based on the difference between, the power loss in driving the engine and the drive train of the vehicle and the power loss in driving the drive train of the vehicle through the control unit; and
determining the friction loss in the engine based on the difference between the motoring loss and the pumping loss in the engine through the control unit.
5. The method as claimed in claim 4, wherein said step of setting the engine of the vehicle in the non-firing state includes switching off an ignition system of the engine.
6. The method as claimed in claim 4, further comprises a step of warming up the vehicle.
7. A chassis dynamometer comprising:
at least one roller adapted for driving at least one wheel of a vehicle;
an electric motor connected to said roller, said electric motor adapted for driving said roller;
at least one load sensor adapted for determining a load provided by an engine and/or drive train of the vehicle;
at least one pressure sensor adapted for determining a pressure inside at least one cylinder in the engine of the vehicle; and
a control unit adapted for determining a friction loss in the engine,
wherein
said load sensor and said pressure sensor is provided in communication with said control unit; and
said control unit determines the friction loss in the engine based on a motoring loss and a pumping loss in the engine, the motoring loss in the engine is determined by said control unit based on the power loss in driving the engine and drive train of the vehicle and the power loss in driving the drive train of the vehicle, wherein the power loss in driving the engine and drive train of the vehicle and the power loss in driving the drive train of the vehicle is determined by said control unit based on the input provided by said load sensor and the pumping loss in the engine is determined by said control unit based on the input provided by said pressure sensor.

Dated this 31st July 2015
Signature:

Name: Kalyan Chakravarthy

ABSTRACT
A chassis dynamometer and a method for testing an engine of a vehicle includes, a roller, an electric motor/generator, a load sensor, a control unit, a pressure sensor, a power supply and frame. The control unit determines friction loss in engine based on a motoring loss and a pumping loss in engine. Motoring loss in engine is determined by control unit based on the power loss in driving the engine and drive train of the vehicle and the power loss in driving the drive train of the vehicle. The power loss in driving the engine and drive train of the vehicle and the power loss in driving the drive train of the vehicle is determined by control unit based on the input provided by load sensor and pumping loss in engine is determined by control unit based on the input provided by pressure sensor.
Fig. 1
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