DESC:FIELD OF INVENTION

The present invention relates to an improved lubrication system in 2-stroke engine. In particular, the present invention relates to an improved lubrication system in two-stroke engines for reducing carbon footprint and to maintain the sustainability. More particularly, the present invention relates to an oil pump controlled through an Engine Control Unit (ECU) for reducing the harmful hydrocarbon emissions.

BACKGROUND OF THE INVENTION

An automatic lubrication refers to the lubrication system on a two-stroke engine, generally used in two-wheelers, e.g. motor cycles or scooters, in which lubrication oil is automatically mixed with fuel. The automatic lubrication system dispenses with manual oil-fuel pre-mixing. Lubrication oil is normally stored in an oil-tank connected to a small oil pump in 2-wheeler (2-stroke) engine. This oil-tank requires refilling of lubrication oil at periodic intervals.

An automatic lubrication offers a consistent lubrication of 2-storke engine and thereby significantly reduces oil consumption thereof. It has much less unwanted carbon deposit on the spark plugs, cylinder heads, pistons and exhaust system and thereby produces significantly reduced exhaust smoke. The refueling of lubrication oil is also substantially simplified with such automatic lubrication.

A more effective engine lubrication results, since oil enters the engine in large-size droplets. In particular, a naturally aspirated 2-stroke engine normally employs a mist lubrication system for lubricating rotating and sliding parts thereof. Lubrication oil is pumped or injected into the intake manifold. Subsequently, 2T oil is supplied from the oil tank by using a crank-driven oil pump.

Generally, an oil pump has a throttle control for controlling the oil quantity being supplied to the engine, which is mechanically controlled by using a throttle cable. Such an oil-pump operates solely depending on the throttle opened by the 2-wheeler driver.

In India, the vehicles with 2-stroke engines running on Compressed Natural Gas (CNG) are generally one of the following types:

• Venturi system
• Port injection
• Direct Injection.

PRIOR ART

At present, blue smoke emanating from any vehicles running on 2-stroke engine is not acceptable under the strict emission norms now in force or soon to be implemented, the requisite conversion from BS IV to BS VI led to this development.

Typically, a 2-stroke engine lubrication system has a wet sump and the lubricating oil is supplied externally by mixing with gasoline or air. Presently, two types of oil lubrication systems are available for 2-stroke engines.

In the first type of oil lubrication system, oil is mixed with fuel. This system consumes large amount of oil, because the required oil quantity is calculated for the maximum load and thermal conditions. Therefore, the oil supplied for part load is more than the required oil quantity. This also contributes to higher HC emissions, leading to serious environmental issues.

In the second type of oil lubrication system, oil is mixed with air by using a positive displacement pump and the drive is typically taken from the crankshaft. The oil quantity increases with the engine rpm. Here, oil metering for part load is controlled by a lever connected in parallel to throttle cable.

Therefore, for reducing Carbon footprint and to effectively maintain the sustainability of the planet, the researchers are continuously attempting to invent more efficient 2-stroke engines with higher fuel economy and significantly lesser emissions. Most of the vehicles running on 2-stroke engines emit excess oil (seen as blue smoke) and this considerably pollutes the environment.

DISADVANTAGES WITH THE PRIOR ART

The main disadvantages with the existing lubrication systems discussed above are that an excess oil quantity is supplied to the combustion chamber, which poses a hindrance in achieving the stringent emission norms. In throttle-controlled oil pumps, supplied oil quantity increases with the opening of the throttle by the vehicle driver.

During low-speeds and at high loads, required oil quantity is less; however, the metered oil quantity is more. Similarly, at low temperatures, the required oil quantity is less; however, the metered oil quantity is more. Both these situations lead to higher pollution, which may result in the environmental degradation.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an improved lubrication system for a 2-stroke engine.

Another object of the present invention is to provide an improved lubrication system for a 2-stroke engine which reduces carbon footprint thereof and therefore helps in maintaining the sustainability.

Still another object of the present invention is to provide an improved lubrication system for a 2-stroke engine which has lower lubricating oil consumption.

Yet another object of the present invention is to provide an improved lubrication system for a 2-stroke engine which has lower HC emission and therefore conforms to the prevailing stringent emission norms.

A still further object of the present invention is to provide an improved lubrication system for a 2-stroke engine which reduces the service frequency of the engine.

A yet further object of the present invention is to provide an improved lubrication system for a 2-stroke engine which reduces the cylinder block-piston cleaning, thereby increases the service life thereof.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an electronically controlled lubricating oil pump for 2-Stroke engines, wherein the oil pump comprises:

• an integrated throttle body;

• an electronic control unit (ECU);

• a throttle position sensor (TPS) to provide the throttle position to the ECU;

• a temperature-manifold pressure (TMAP) sensor to provide temperature and pressure values within the manifold to the ECU;

• an electrical device for controlling the oil pump throttle;

wherein the oil pump throttle is controlled and calibrated depending on the manifold absolute pressure (MAP) prevailing inside the manifold as detected by the TMAP sensor.
Typically, the ECU controls the lubricating oil supplied to the combustion chamber, piston, engine block, connecting rod and crankshaft through air-oil mixture by a controlled operation of the electrical device by using a table (TPS vs speed) calibrated in the ECU.

Typically, the electrical device is a stepped motor or a DC motor.

Typically, the table uses the correction based on various temperatures and pressures inside the manifold to which the engine is subjected and detected by the TMAP sensor.

Typically, the lubricating oil supply is controlled based on the engine requirement by considering the temperature, engine load and pressure by means of the ECU and the electrical device.

In accordance with the invention, there is also provided an electronically controlled lubricating oil pump for 2-Stroke engines, wherein the oil pump comprises: an integrated throttle body including an electronic control unit (ECU) and a throttle position sensor (TPS) to provide the throttle position to the ECU; a temperature-manifold pressure (TMAP) sensor to provide temperature and pressure values within the manifold to the ECU; a stepped motor or DC motor for controlling the oil pump throttle; wherein the oil pump throttle is controlled and calibrated depending on the manifold absolute pressure (MAP) prevailing inside the manifold as detected by the TMAP sensor.

Typically, the ECU controls the lubricating oil supplied to the combustion chamber, piston, engine block, connecting rod and crankshaft through air-oil mixture by a controlled operation of the electrical device by using a table (TPS vs speed) calibrated in the ECU.

Typically, the table uses the correction based on various temperatures and pressures inside the manifold to which the engine is subjected and detected by the TMAP sensor.

Typically, the lubricating oil supply is controlled based on the engine requirement by considering the temperature, engine load and pressure by means of the ECU and the electrical device.

In accordance with the present invention, there is further provided a method for precise electronic control of the lubricating oil supply to the oil-pump of a 2-Stroke engine by using an electronically controlled lubricating oil pump as claimed in claims 1 to 9, wherein the method comprises the following steps:

• Continuously detecting the throttle position by means of the throttle position sensor (TPS) and supplying the same to the electronic control unit (ECU);

• Continuously detecting the temperature and pressure within the manifold throttle and supplying the same to the electronic control unit (ECU);

• Electronically controlling the lubricating oil supply to the combustion chamber, piston, engine block, connecting rod and crankshaft through oil-air mixture;

wherein the lubricating oil supplied via oil-air mixture is electronically controlled by a controlled operation of the stepped motor by using a table for throttle position versus speed pre-calibrated in the ECU based on the correction values detected by the TMAP sensor for various temperatures and pressures to which the engine is subjected.

DESCRIPTION OF THE INVENTION

The lubrication system configured in accordance with the present invention facilitates in controlling the release of the harmful emissions to the environment and to precisely calibrate the oil quantity required for a particular load and rpm of the 2-stroke engine for running a vehicle. Here, the oil pump throttle is electronically controlled by using an electrical device (e.g. stepper motor, DC motor etc.) controlled by an ECU depending on the calibrated manifold absolute pressure (MAP).
This improved lubrication system helps in achieving very stringent emission norms currently in force like BS VI or which are yet to be put in place and thus also reduces the oil consumption in 2-stroke engines.

This invention successfully facilitates in controlling the supplied oil quantity and permits only the required lubricating oil quantity to 2-stroke engine. Although, there is a significant cost addition due to deployment of the electronic control unit (ECU), this new technology is quite efficient and offers a substantial competitive edge to the applicants over their competitors. It is also effective in reducing lubricating oil consumption and achieving the much desired BS VI emissions.

The oil pump configured in accordance with the present invention includes an oil metering by means of a stepped motor. Accordingly, the oil quantity required for actual load conditions is calibrated by using a 2D map stored in the engine control unit (ECU), which also facilitates an oil temperature correction, whenever required.

Therefore, the oil-pump configured in accordance with the present invention enables to maintain the correct oil level at all engine speeds (rpm) and all load conditions.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, wherein:

Figure 1 shows a conventional throttle-controlled oil pump with the drive shaft thereof connected to the crankshaft of a 2-stroke engine.

Figure 2a shows a front view of the conventional throttle-controlled oil pump of Fig.1.

Figure 2b shows a perspective view of the conventional integrated throttle body of the throttle-controlled oil pump of Fig.2a.

Figure 3 shows a front view of the oil pump configured in accordance with the present invention.

Figure 4 shows a side view of the oil pump of Fig.3 configured with a stepped-motor.

Figure 5 shows a rear view of the conventional throttle-controlled oil pump of Fig.1.

Figure 6 shows another side view of the oil pump of Fig.3 with a stepped-motor.

Figure 7 shows a schematic diagram of an oil pump of a 2-stroke engine depicted in Figure 3 and the oil supply thereof.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, the oil-pump provided with a stepped motor configured in accordance with the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a conventional throttle-controlled oil pump 10 with the drive shaft 12 thereof connected to the crankshaft of a 2-stroke engine (not shown here).

Figure 2a shows a front view of the conventional throttle-controlled oil pump 10 of Figure 1. It includes a throttle lever 14, an oil tank 16 for 2T oil used for lubrication in a 2-stroke engine. This 2T oil is supplied to the oil pump 10 via a supply line 18. Another line 20 supplies the oil pumped by the oil pump 10 to a 2-stroke engine 30 (not shown here).

Figure 2b shows a perspective view of the conventional integrated throttle body 22 of the throttle-controlled oil pump 10 of Fig.2a. The throttle lever 14 is connected in parallel to a throttle cable (not shown) for controlled oil metering for part loads.

Figure 3 shows a front view of the oil pump 100 configured in accordance with the present invention controlled by an electrical device, e.g. a stepped-motor or DC motor 110.

Figure 4 shows a side view of the oil pump 100 of Fig.3 with a stepped-motor 110.

Figure 5 shows a rear view of the conventional throttle-controlled oil pump of Fig.1.

Figure 6 shows another side view of the oil pump of Fig.3 with a stepped-motor.

Figure 7 shows a schematic diagram of an oil pump 100 of a 2-stroke engine depicted in Figure 3 configured with a stepped-motor 110. Integrated throttle body 116 has a throttle position sensor (TPS), which provides the throttle position to ECU 112, while temperature-manifold absolute pressure (TMAP) sensor provides the temperature and pressure values within the manifold to ECU 112. The lubricating oil to the combustion chamber 114, piston 132, engine block 130, connecting rod 134 and crankshaft 136 supplied via air mixture is electronically controlled by an ECU 112 by a controlled operation of the stepped motor 110 by using a table (TPS vs speed) calibrated in ECU 112. This table uses the correction based on the TMAP sensor for various temperatures and pressures that the engine is subjected to. ECU 112 is also electrically connected to the MAP sensor 118 and integrated throttle body 122. The oil supply is controlled based on the engine requirement by taking into consideration of the temperature, engine load and pressure with the help of ECU 112 and stepper motor 110. This significantly reduces the oil consumption and thereby reduces the HC emission to the atmosphere. Therefore, a precise emission control is made possible by this electronically controlled oil-pump.
This was not possible until now because in the available prior art oil pumps are mechanically controlled based on the throttle position connected by a throttle cable.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The oil-pump provided with a stepped motor and configured in accordance with the present invention has the following technical and economic advantages:

• Low lubricating oil consumption.

• Low HC emission, thus conforms to stringent emission norms like BS VI.

• Less service frequency- Block piston cleaning.

• Increased block-piston life.

• Reduces carbon footprint and helps in maintaining the sustainability.

• Precise control over the oil quantity calibrated for actual load conditions.

• ECU also precisely controls lubricating oil temperature.

• Maintains a correct oil level at all engine speeds (rpm) and all load conditions.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention.

These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. ,CLAIMS:We claim:

1. An electronically controlled lubricating oil pump for 2-Stroke engines, wherein the oil pump comprises:

• an integrated throttle body;

• an electronic control unit (ECU);

• a throttle position sensor (TPS) to provide the throttle position to the ECU;

• a temperature-manifold pressure (TMAP) sensor to provide temperature and pressure values within the manifold to the ECU;

• an electrical device for controlling the oil pump throttle;

wherein the oil pump throttle is controlled and calibrated depending on the manifold absolute pressure (MAP) prevailing inside the manifold as detected by the TMAP sensor.

2. Electronically controlled lubricating oil pump as claimed in claim 1, wherein the ECU controls the lubricating oil supplied to the combustion chamber, piston, engine block, connecting rod and crankshaft through air-oil mixture by a controlled operation of the electrical device by using a table (TPS vs speed) calibrated in the ECU.

3. Electronically controlled lubricating oil pump as claimed in claim 1, wherein the electrical device is a stepped motor or a DC motor.

4. Electronically controlled lubricating oil pump as claimed in claim 2, wherein the table uses the correction based on various temperatures and pressures inside the manifold to which the engine is subjected and detected by the TMAP sensor.

5. Electronically controlled lubricating oil pump as claimed in claim 2, wherein the lubricating oil supply is controlled based on the engine requirement by considering the temperature, engine load and pressure by means of the ECU and the electrical device.

6. An electronically controlled lubricating oil pump for 2-Stroke engines, wherein the oil pump comprises: an integrated throttle body including an electronic control unit (ECU) and a throttle position sensor (TPS) to provide the throttle position to the ECU; a temperature-manifold pressure (TMAP) sensor to provide temperature and pressure values within the manifold to the ECU; a stepped motor or DC motor for controlling the oil pump throttle; wherein the oil pump throttle is controlled and calibrated depending on the manifold absolute pressure (MAP) prevailing inside the manifold as detected by the TMAP sensor.

7. Electronically controlled lubricating oil pump as claimed in claim 6, wherein the ECU controls the lubricating oil supplied to the combustion chamber, piston, engine block, connecting rod and crankshaft through air-oil mixture by a controlled operation of the electrical device by using a table (TPS vs speed) calibrated in the ECU.

8. Electronically controlled lubricating oil pump as claimed in claim 7, wherein the table uses the correction based on various temperatures and pressures inside the manifold to which the engine is subjected and detected by the TMAP sensor.

9. Electronically controlled lubricating oil pump as claimed in claim 7, wherein the lubricating oil supply is controlled based on the engine requirement by considering the temperature, engine load and pressure by means of the ECU and the electrical device.

10. A method for precise electronic control of the lubricating oil supply to the oil-pump of a 2-Stroke engine by using an electronically controlled lubricating oil pump as claimed in claims 1 to 9, wherein the method comprises the following steps:

• Continuously detecting the throttle position by means of the throttle position sensor (TPS) and supplying the same to the electronic control unit (ECU);

• Continuously detecting the temperature and pressure within the manifold throttle and supplying the same to the electronic control unit (ECU);

• Electronically controlling the lubricating oil supply to the combustion chamber, piston, engine block, connecting rod and crankshaft through oil-air mixture;

wherein the lubricating oil supplied via oil-air mixture is electronically controlled by a controlled operation of the stepped motor by using a table for throttle position versus speed pre-calibrated in the ECU based on the correction values detected by the TMAP sensor for various temperatures and pressures to which the engine is subjected.

Dated: this 30th day of August 2016. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT