ENGINE OPERATING STATUS INDICATION SYSTEM FOR AN AUTOMOTIVE VEHICLE

FIELD OF THE INVENTION

[0001] The present invention relates to an 'engine load indication system for an automotive vehicle and more particularly to a system which displays engine operating status based on various inputs.

BACKGROUND OF THE INVENTION

[0002] The fuel consumption of an automotive vehicle can be minimized if the engine load is maintained within a particular range. Engine load is dependent on user driving pattern, road conditions and vehicle payload. It will be beneficial if an indication is provided regarding an economical engine operating range so that the user can adjust his/her riding pattern thereby maximizing fuel efficiency.

[0003] Indian Granted Patent IN200994 discloses a display unit for a two-wheeler wherein an economy mode and power mode indication is provided on a vehicle based on throttle position. A throttle pipe provided on the two-wheeler for allowing the rider to control air-fuel mixture quantity is connected with a throttle switch, which changes state based on the throttle position. The throttle switch is also connected with an ignition control unit and speedometer of the vehicle.

[0004] Economy mode and power mode indications are provided in the speedometer to indicate the engine operating state to the rider. For throttle position within a predetermined range, the throttle switch maintains a particular state and an economy mode indication bulb in speedometer will glow. For throttle position beyond the predetermined range, the throttle switch state changes and a power mode indication bulb will glow. Such a throttle position based indication system requires a throttle switch as mentioned above and a throttle cable to link the throttle switch to the throttle system resulting in increased number of parts, which reduces system accuracy.

[0005] US Patent Publication US4723215 discloses a method for indicating a vehicle operation in a fuel economy range for an automotive vehicle with manual transmission. If the vehicle operating condition does not satisfy an up-shift or down-shift requirement condition and if it does not satisfy a vehicle irregular operating condition then economy range indication is enabled. This system however requires a number of sensors including throttle position sensor, vehicle speed sensor, crank angle sensor, engine coolant temperature sensor, manifold air pressure sensor and clutch position sensor. The cost and complexity of the vehicle increases when such a system is used.

[0006] Therefore to obviate defects in the prior art, there is required an engine load indication system which uses minimum number of sensors and is highly reliable and cost effective and this forms the principle objective of the present invention.

SUMMARY OF THE INVENTION

[0007] An engine operating indication is very much desirable in a motorcycle for improving the fuel economy and usage of better riding procedures. The higher torque desired by the rider of a two wheeler is achieved by allowing more fuel and air to enter inside the cylinder which is required mainly during overtaking another vehicle on a road or for travelling a longer distance in the quickest time. Many a times, for normal use of a personal automotive vehicle, rider unknowingly runs the vehicle at higher engine rpm than desired. There is a requirement for a fuel economy conscious rider of an automotive vehicle to receive a feedback from the instrument cluster regarding whether the engine is operating within the range of economy usage or not.

[0008] This economical range of operation of the automotive vehicle can be obtained from a mapping of engine rpm, throttle position and speed of the vehicle. Hence by using such a feedback system for engine operating status in a two wheeler, a rider, if he by mistake goes in the power mode and later realizes that cruising in power mode is undesired for his requirement, he may bring back the two wheeler engine speed in the economy mode of operation. For mileage conscious riders and users of a two wheeler, the current invention provides an indication on the instrument cluster for informing the driver regarding the status of the engine operation in one of two modes wiz. economy mode and power mode.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 shows a typical two wheeler.

[00010] Figure 2 shows a block diagram for detecting the engine load.

[00011] Figure 3 shows the rotor and pip mechanism for detecting engine rpm.

[00012] Figure 4 shows the engine parameters display.

DETAILED DESCRIPTION OF THE INVENTION

[00013] As shown in Figure 1, a typical motorcycle 11, with a fuel tank 12 is shown. The fuel tank 17 acts as a storage unit for the fuel. The motorcycle 11 has an engine 13, an exhaust muffler 19 and wheels 15.0ne end of the exhaust muffler 19 is connected to the exhaust port of the engine 13. The exhaust gas passes through a catalytic convenor 21 which is placed inside the exhaust muffler 19. The carrying away of burnt and unburnt gases during combustion through the exhaust muffler, increases its temperature and consequently the exhaust muffler attains a very high temperature while the vehicle is in use. The vehicle speed, fuel level and other driving parameters are displayed on the instrument cluster 22.

[00014] Figure 2 illustrates an exemplary embodiment of the engine load indication system for an automotive vehicle as per the present invention. An Electronic Control Unit (ECU) 10 receives engine speed signal input from a pulser coil 20 and gear position signal input from a gear position sensor 81. The ECU 10 operates using electric power supplied by a vehicle battery 30. One of the outputs of the ECU 10 is fed as an input to an indication unit 70, which comprises an engine operating status display means. This engine operating display means consists of atleast one display unit for displaying the engine operating status. There are atleast two displays to show economy mode and the power mode on the said display unit.

[00015] The ECU 10 also provides ignition signal to an ignition coil 40 in order to control operation of a spark ignited internal combustion engine of the automotive vehicle. The driver circuit 18 has plurality of signal and switching circuits. The output of driver circuit 18 is fed as input to the indication unit and the ignition coil. The timed output of ignition coil is sent to the spark plug for generating spark plug for producing spark required for combustion of fuel in the engine cylinder.

[00016] In the current invention, as shown in the block diagram in Figure 2, the signal conditioning consists of analog to digital and digital to analog convertors. The input signals received by the signal conditioning module from the pulser coli 20 and the gear position sensor 81 can be either analog or digital signals depending upon the type of sensor output available. The signal conditioning that is being done in the ECU 10 is done to provide the microcontroller 12, a compatible signal for its operation.

[00017] The ECU 10 further comprises a micro-controller 12 for performing computing operations, a signal conditioning circuit 14 for converting the input signals into levels suitable for processing by the micro-controller 12, a power supply circuit 16 for supplying electric power at suitable voltage and current levels to the micro-controller 12 and signal conditioning circuit 14 and a driver circuit 18 for driving the indication unit 70 to display the engine operating status.

[00018] Referring to Figure 3, the pulser coil 20, which is a commonly used variable reluctance type sensor, generates a voltage signal indicative of a rotor 80 position. A ferromagnetic projection 90 is provided on rotor 80, which is coupled to a crankshaft of the engine. The pulser coil 20 is fixedly mounted on to a crankcase of the vehicle and is separated from the rotor 80 by a pre determined radial air-gap. The pulser coil 20 has an in-built magnet and coil wound around a soft ferromagnetic core. During rotation of the rotor 80 due to engine operation, the flux linked with pulser coil 20 changes. Whenever the leading edge 92 of projection 90 passes the pulser coil 20, the air-gap reduces and thereby increases the flux linkage. When the trailing edge 94 of projection 90 passes the pulser coil 20, the air-gap increases and thereby reduces the flux linkage. The pulser coil gives a signal in the form of voltage signal at the instances when the projection 90 passes the pulser coil 20. This signal is fed to the signal conditioning unit 14 which converts the said signal into a signal compatible with input port of the microcontroller 12 inside the ECU. The change in flux linkage induces a voltage across the pulser coil 20, which is in turn indicative of the engine speed. The

[00019] This engine speed signal input is used by the micro-controller 12 to calculate engine speed. The micro-controller 12 also determines gear position from the gear position sensor output. Gear position and engine speed is used by the micro-controller 12 to predict the engine load. A look-up table is stored in the micro-controller 12, which defines an engine operating state based on the predicted engine load, the engine speed and the gear position. The look-up table is experimentally obtained for a vehicle based on tests conducted in a chassis dynamometer considering fuel efficiency, engine power, exhaust emissions and driving comfort. The engine

WE CLAIM:

1. A method for determining engine operating status comprising the steps of: storing different set of combination of engine speed and engine load, in a lookup matrix; forming plurality of sets of various ranges of the said engine speed and the said engine load; wherein every set of this look-up matrix is assigned one unique status out of atleast two indicating statuses namely economy mode and power mode; real time data acquisition of engine speed by using a pulser coil; calculating real time engine load from the said engine speed data; comparison of real time data of the engine speed and the engine load with the data stored in the said look up matrix; whereby obtaining the engine operating status from the said comparison and thereby displaying the said unique mode of engine operating status on a display means.

2. An engine operating status indication system for an automotive vehicle comprising: a vehicle battery which powers an Electronic Control Unit (ECU); a pulser coil which provides engine speed signal input to the ECU; an indication unit having an engine operating status display means, which receives the engine operating status input from the ECU; wherein the ECU determines engine operating status based on a predetermined look up table which has engine load, engine speed and gear position as input parameters.

3. The sets of combinations of engine load(s) and engine speed(s) corresponding to the engine operating status indication as claimed in claim 1 is stored in the microcontroller memory and is compared in real time with the real time process parameters to assign one unique mode out of atleast two indicating modes namely economy mode and power mode.

4. The engine operating status indication system for an automotive vehicle as claimed in clam 1 and claim 2 wherein the ECU further comprises a signal conditioning circuit, a micro-controller, a power supply circuit and a driver circuit.

5. In the engine operating status indication system for an automotive vehicle as claimed in claim 1 and claim 2; the signal conditioning circuit converts engine speed signal into levels suitable for processing by the micro-controller; the micro-controller determines engine speed and engine load from the input obtained from the signal conditioning unit, and the driver circuit gives signal to the indication unit, which displays engine operating status based on the predetermined look-up table stored in the micro¬controller; the driver circuit also gives signal to the ignition coil.

6. The engine operating status indication system for an automotive vehicle as claimed in claim 1 and claim 2 wherein the pulser coil is a variable reluctance type sensor.

7. The engine operating status indication system for an automotive vehicle as claimed in claim 1 and claim 2 comprises of multi color bar graph indication.

8. In the engine operating status indication system for an automotive vehicle as claimed in claim 7; the number of bars and color of the bar graph indication varies according to engine operating status.

9. The engine operating status indication system for an automotive vehicle as hereinabove described in the specification with the accompanying drawings.