This invention relates to an engine control system for a motor vehicle.

An object of this invention is to propose an engine control system for a motor vehicle for the purpose of controlling the operation of the engine based on engine oil level; and for cautioning the user when the engine oil decreases below predetermined levels in the oil sump..

The proposed system operates for a spark ignition engine, preventing its seizure by controlling the operation of the engine, based on the engine oil level, while providing a warning to the user about decrease in engine oil level below given values.

Engine oil is essential for lubrication of the moving parts in the engine. Adequate engine oil is required for smooth operation of the engine. Insufficient engine oil results in increased losses due to friction between the moving parts resulting in reduced fuel efficiency and increased wear of the moving parts. Frequently, it is neglect on the part of the user that results in the operation of the engine at low engine oil level. Often, the user does not feel compelled to change the engine oil periodically.

The engine control system proposed herein (abbreviated to ECS when necessary) is an electronic system that receives an input from sensors installed in the vehicle, processes the input data and changes the operating point of the engine to optimise efficiency of the engine and thus provide good response to the user.

In the case of the spark ignition engine, the ECS determines the ignition timing with respect to the position of the piston. As there is at least one spark plug mounted in the engine, when high voltage is applied to the spark plug there will be a spark appearing across the spark plug gap. The air-fuel mixture that is sucked into the combustion chamber is ignited by means of this spark, causing combustion of the air-fuel mixture. There is an ignition coil that converts the low voltage signal provided by the ECS to the high voltage signal required for the spark plug. The instant of application of the low voltage signal is varied by the ECS thus resulting in variation of the ignition timing.

In the accompanying drawings,

Fig. 1’illustrates the block diagram for the ignition system with the ECS
And

Fig. 2 illustrates the flowchart for the ECS operation

The invention proposed herein obtains input from an engine oil level sensor. The engine oil level sensor does not provide any signal when the engine oil level is full. When the engine oil level decreases to a predetermined medium level, the engine oil level sensor provides a continuous low signal to the ECS. When the engine oil level decreases further to a predetermined low level, the engine oil level sensor provides a continuous high signal to the ECS.

The ECS on reception of a low signal from the engine oil level sensor checks if the low signal is present for 15 seconds. If the low signal is present for 15 seconds continuously, the ECS turns on a beeper for 10 seconds and turns off the beeper for 300 seconds thus forming one beeper cycle. This beeper cycle is repeated as long as the engine oil level sensor provides low signal to the ECS. The ECS also provides a continuous Ground (GND) signal to a warning lamp on the instrument panel so that the warning lamp glows. The beeper sound together with the warning lamp glow warns the user about the decrease in the engine oil level below a predetermined level.

The ECS on reception of a high signal from the engine oil level sensor checks if the high signal is present for 15 seconds. If the high signal is present for 15 seconds continuously, the ECS turns on the beeper continuously. The ECS also provides a continuous Ground (GND) signal to a warning lamp on the instrument panel so that the warning lamp glows.

The ECS checks if the high signal is present for 50000 revolutions of a magneto or alternator present in the engine. A magneto or alternator is used to generate electricity in a vehicle with internal combustion engine. The magneto or alternator is coupled to the crank shaft of the engine and hence rotates in synchronism with the crankshaft. If the high signal is present for 50000 revolutions of the magneto or alternator, the ECS cuts off one spark per 10 revolutions of the magneto or alternator by abstaining from providing signal to the ignition coil once every 10 revolutions of the magneto- This absence of spark once every 10 revolutions of magneto results in jerks in engine operation. It prompts the user to top up the engine oil.

The ECS checks if the high signal from the engine oil level sensor is present for 100000 revolutions of the magneto or alternator. If the high signal is present for 100000 revolutions of magneto continuously, then the ECS cuts off one spark per five revolutions of the magneto by abstaining from providing signal to the ignition coil once every five revolutions of the magneto. This results in frequent jerks and is quite annoying to the user.

The ECS checks if the high signal from the engine oil level sensor is present for 150000 revolutions of the magneto or alternator continuously. If the high signal is present continuously for 150000 cycles and if the engine speed is less than 2500 revolutions per minute, then the ECS stops the ignition by not providing signal for the ignition coil. The engine stops without ignition and hence the user is compelled to change the engine oil.

Once the ignition switch for the vehicle is turned off and then turned on, the ECS is reset and it starts checking the input from the engine oil level sensor and responds accordingly as explained above.
The Engine Control System mentioned herein can be an Inductor Discharged Ignition or a Capacitor Discharged Ignition.

The time delay (15 seconds in the embodiment explained) to check the state of the oil level can be different. The number of magneto revolutions (5()()()0 magneto revolutions in the embodiment explained) before which the spark is cut periodically can be different.

The rate at which the spark is cut (1 spark per 10 magneto revolutions initially and 1 spark per 5 magneto revolutions after another 50000 magneto revolutions in the embodiment explained can be different.
The means of detection of the engine oil level from the sensor can be different, that is, medium engine oil level need not necessarily send low signal to ECS and low engine oil level need not necessarily send high signal to ECS. They can be any two different signals that the ECS can recognize.

The engine speed is checked before signaling shut off of the engine to allow smooth and safe shut off of the engine and hence ensuring user safety.

Figs. 1 and 2 illustrate respectively the block diagram for the ignition system with the ECS and the flowchart for the ECS.

What has been described above and illustrated is by reference to an embodiment of this invention and it will be appreciated that various other embodiments thereof are possible without departing from its scope and ambit.

We Claim:

1 An engine control system for a motor vehicle comprising an electronic controller; a sensor for the engine oil sump connected to the controller, said sensor feeding input signals to the controller when predetermined decreases in engine oil level occur, said controller processing the input signals for sending out output signals; perceptible means of cautionary indication for receiving the said output signals and means for also receiving the said output signals to control the ignition pattern of the engine.

2. An engine control system as claimed in Claim 1 wherein the perceptible means of indication consist of cautionary lights provided on the instrument panel of the vehicle.

3. An engine control system as claimed in Claim 1 or Claim 2 wherein the perceptible means of indication consist of cautionary beepers provided on the instrument panel of the vehicle.

4. An engine control as claimed in any one of the preceding Claims wherein controlling the ignition pattern consists in disrupting the sparking of the engine.

5. An engine control as claimed in any one of the preceding Claims wherein controlling the ignition pattern consists in shutting off the ignition of the engine at predetermined low speeds of the vehicle.

6. An engine control system for a motor vehicle substantially as herein described with reference to, and as illustrated in, the accompanying drawings.