Title of Invention

ROLLER TAPPET WITH COLD ADVANCE

Abstract

This invention in general relates to a Roller tappet device for warm start and adapted for cold start use on single and multi-cylinder diesel engine with PF pumps. The Roller Tappet device with cold advance provide quick warm up and thereby achieve the emission requirements with reference to cold start and white smoke. The roller tappet includes a movable piston which advance is the plunger position, a plate valve connected to the lubricating oil supply pump such that lubricating oil flowing through the said plate valve provides the upward thrust on the movable piston which in turn lifts and thereby advances the plunger towards the top, a stopper means to limit the stroke of the piston; a cut off means to cut off the lubricating oil supply and a return means of throttle hole on said plate valve to facilitate the collapse of the plunger position via the lubricating cut off means in warm condition. This invention thus decides the position of the plunger depending on the start up warm to cold condition and advance position is created.

Full Text

ROLLER TAPPET WITH COLD ADVANCE PRIOR ART Various devices are In existence for Injection related to single and multi cylinder diesel engine with PF pumps. The main draw back In the existing art is :- a. Difficulty in achieving easy start, b. Difficulty In achieving quick warm-up, c. Difficulty In achieving start In cold condition. d. Difficulty In achieving the emission requirements with reference to cold start and white smoke. The known prior process is not satisfactory and is not convenient. As herein mentioned in this invention hereinafter, the performance can be highly enhanced, if there is a device, which providesa quick warm-up and easy starting from a cold condition and the device performs normally in a warm condition. Thus according to this invention there is provided an improvement, which according to the Invention exhibits considerably Improved performance over the devices of the prior art, by allowing the plunger to be in advance position when the condition is cold. OBJECT OF THE INVENTION This Invention relates to a Roller Tappet device for advancing the Injection beginning in cold condition (- 25°C to + 40°C) In single and multi-cylinder diesel engine with PF pumps, for easy startability and quick warm up and to achieve the emission requirements with reference to cold start and white smoke. SUMMARY OF THE INVENTION The invention relates to a Roller Tappet device for advancing the injection beginning in cold condition (- 25°C to + 40°C), in single and multi-cylinder diesel engine with PF pumps, by means of which the injectbn onset is adjusted in cold condition and also in normal condition; and comprising of :- a. A piston so provided in the Roller Tappet, such that it moves up and down the said Roller Tappet, due to flow of lubricating oil from lubricating oil supply pump which is at a pressure of 2.5 - 3 bar, through a plate valve. Said lubricating oil which flows through the said plate valve, lifts the said hydro tappet piston by 1.5 mm. The said 1.5 mm lift enables the plunger to be 1.5 mm in advance position. The said 1.5 mm lift of the said plunger corresponds to 8° to 10° crank angle depending upon the cam profile. The stroke of the said piston is limited by a stopper. The said stroke of the Roller Tappet device is so designed that under the existing cold condition, the piston is advanced to the extent desired by creating an equivalent pressure in the lubricating oil and the stopper such that the piston is held in desired advance position. The said plate valve connected to lubricating oil pump provides a hydraulic lock and therein prevents the said lubricating oil leakage due to Injection pressure. The said plate valve is provided with a throttle hole. A return means is provided wherein the said throttle hole facilitates the collapse of the said plunger to the normal position as soon as the said lubricating oil supply is cut-off by cut-ff means, due to the leakage of the said lubricating oil through the said throttle hole on the said plate valve. The size of the said throttle hole on the said plate valve, is relative to the selected diameter of the said plunger and the peak injection pressure of the pump. b. Application of the Invention : This Roller Tappet device is recommended for use on single and multi cylinder diesel engine with PF pumps. c. Function of the Invention : The function of the Roller Tappet device is to advance the injection beginning In cold condition (- 25°C to + 40°C). d. Working principle of the invention : When the Roller Tappet is in Bottom Dead Centre position, lubricating oil, which is at a pressure of 2.5 to 3.0 bar, flows through the plate valve and lifts the hydro tappet piston by 1.5 mm. With this, the plunger is 1.5 mm in advance position as compared to normal operating position. This 1.5 mm lift corresponds to 8° to 10° crank angle depending upon the cam profile. The stopper limits the stroke of the piston. The stroke of the device is relative to the cold advance, the piston advanced to an extent decide by creating an equalent pressure in the lubricating oil and limiting the advance by the stopper means such that the piston is held in a forward position at a decide location as decide which is further relative to the requirement of the engine. The plate valve connected to lubricating oil supply pump provides a hydraulic tockand prevents the lubricating oil leakage due to injection pressure. When the engine is in cold condition (-25°C to + 40°C), the plunger is in advance position. In the warm condition ( >40°C) the lubricating oil is cut off. Due to the lubricating oil leakage through the throttle hole on the plate valve, the plunger collapses back to the normal operating position. In cold condition, the lubricating oil inlet pressure prevents the lubricating oil leakage through the throttle hole. The size of the throttle hole is selected depending upon the plunger diameter and the peak injection pressure of the pump. e. Advantages of the invention :- Easy start ability and quick warm up ; To achieve the emission requirements with reference to cold start and white smoke. The invention is related to the Roller Tappet device consisting of a piston which moves up and down in the Roller Tappet against plunger spring force and lifts the plunger due to the lubricating oil pressure, a plate valve which provides hydraulic lock and throttle hole on the plate valve which facilitates the collapse of the plunger to the normal position as soon as the lubricating oil supply is cut off. DETAILED DESCRIPTION OF THE INVENTION Thus according to the invention, a Roller Tappet device for warm start and adaptable for variation of plunger position in advance for cold start for use in single and multi cylinder diesel engine with PF pumps, comprises of :- (-) lubricating oil supply pump to supply oil at desired pressure to Roller Tappet. (-) a mova ble piston in the Roller Tappet to adjust the plunger position in advance and thereby achieve desired crank angle. (-) a Plate valve connected to lubricating oil supply pump such that the lubricating oil flowing through the plate valve providesa force thrust on the piston, which lifts the piston upward and thereby advances the plunger position. (-) a stopper means connected to piston to limit the stroke of the piston. (-) a cut off means connected to lubricating supply means such that the lubricating oil supply is connected or cut off to Roller Tappet. (-) a return means wherein throttle hole is provided on said plate valve such that throttle hole facilitates the collapse of said plunger position upon activation of oil supply cut off by cut off means. A piston so provided in the Roller Tappet, such that it moves up and down the said Roller Tappet, due to flow of lubricating oil from lubricating oil supply pump which is at a pressure of 2.5 - 3 bar, through a plate valve. Said lubricating oil which flows through the said plate valve, lifts the said hydro tappet piston by 1.5 mm. The said 1.5 mm lift enables the plunger to be 1.5 mm in advance position. The said 1.5 mm lift of the said plunger corresponds to 8° to 10° crank angle depending upon the cam profile. The stroke of the said piston is limited by a stopper. The said stroke of the Roller Tappet device is calculated such that the lift and advancement of piston plunger is relative to the cold advancement requirement of the engine. The position of the plunger in advance position is decided by cold condition factors and is predetermined . Generally in cold condition the Roller Tappet which is at bottom dead centre position and the lubricating oil is at a pressure flows through the plate valve and advance the piston position. The extent of advancing the position and the extent of advancement is decided by cold condition requirement. The said plate valve provides a hydraulic lock and therein prevents the said lubricating oil leakage due to injection pressure. The said plate valve is provided with a throttle hole. A return means provided wherein the said throttle hole facilities the collapse of the said plunger tome normal position as soon as the said lubricating oil supply is cut-off by cut-off means, due to the leakage of the said lubricating oil through the said throttle hole on the said plate valve. The size of the said throttle hole on the said plate valve, is relative to the selected diameter of the said plunger and the peak injection pressure of the pump. In the embodiment described, the Roller Tappet according to the invention achieves easy start ability and also achieves quick warm up. The Roller Tappet device, according to the invention has been described herein in relation to :- a. Cold condition ; b. Warm condition, Without departing from the scope and spirit of the invention, the Roller Tappet device according to the invention is easily adaptable for extended range of temperature other than specified herein in this specification. Cold Condition When the Roller Tappet is in Bottom Dead Centre position, lubricating oil which is at a pressure of 2.5 to 3.0 bar, flows through the plate valve and lifts the hydro tappet piston by 1.5 mm. The lubricating oil Inlet pressure prevents the lubricating oil leakage through the throttle hole in the plate valve. With the t of the said piston by 1.5 mm, the said plunger is 1.5 mm in advance position Native to normal operating position. The said 1.5mm lift corresponds to 8° to 3° crank angle depending upon the cam profile. The stroke of the piston is mited by providing a stopper. The stroke of the device is based on the cold dvance requirement of the engine. Thus In a cold condition (- 25PC to + 4CfC), ie lubricating oil which is at a pressure lifts the piston and pushes the plunger \ advance position and the hydraulic lock of the plate valve, as herein described bove, holds the plunger in advance position. Yarm Condition When the engine is in warm condition, the lubricating oil supply is cut off. rhe throttle hole on the plate valve a Hows the leakage of the lubricating oil, and acilitates the plunger collapse back to normal operating position. Description of the invention with reference to Drawings ;- An embodiment of the invention will now be described by way of Illustration and example, and without limiting the scope of the inventton, with reference to the accompanying drawings in which :- Fig. 1- shows the cross sectional view of the Roller Tappet with cold advance. The device consists of the Roller Tappet with cold advance piston, a plats valve, valve spring, stopper and plunger spring. The pump plunger and tappet spring are also shown. The fuel injection cam is shown in BDC position. The cold advance piston is in the collapsed condition. Fig. 2- shows the assembly drawing of a cold advance Roller Tappet for a particular application, consisting of item no.l - Roller Tappet with cold advance piston, item no. 2 - stopper, item no.3 - valve spring and item no.4- plate valve. The cold advance lift for this application is 0.75 mm. Fig. 3- shows a PF mono block fuel injection pump with cold advance Roller Tappet. The pump is mounted on the engine crank case. The Roller Tappet guided in the engine, is driven by a fuel injection cam on the engine. Lubricating oil is supplied to the cold advance Roller Tappet at a pressure of 2.5 to 3 bar. Fig. 4 - shows the test results of the cold advance Roller Tappet sample at cam speed 1400 rpm. The first graph shows the fuel injection curve at the nozzle end in the initial position. The second graph shows the injection curve advanced by 10 deg crank, when 2.5 bar lubricating oil is supplied to the Roller Tappet. The third graph shows the fuel injection curve back in the initial position when the lubricating oil supply is cut off. This applies to the warm condition. The collapsing time at this speed is 3 seconds. WE CLAIM 1. A Roller Tappet device for warm start and adaptable for variation of plunger position in advance for cold start for use on single and multiple cylinder diesel engine with PF pump, the Roller Tappet device comprising of, lubricating oil supply pump to supply oil at desired pressure to Roller Tappet, a movable piston in the Roller Tappet to adjust the plunger position in advance and thereby achieve desired crank angle, a Plate valve connected to lubricating oii supply pump such that the lubricating oil flowing through the plate valve provides a force thrust on the piston, which lifts the piston upward and thereby advances the plunger position, a stopper means connected to piston to limit the stroke of the piston, a cut off means connected to lubricating supply means such that the lubricating oil supply is connected or cut off to Roller Tappet, and a return means wherein throttle hole is provided on said plate valve such that throttle hole facilitates the collapse of said plunger position upon activation of oil supply cut off by cut off means. 2. A Roller Tappet device for warm start and adaptable for variation of plunger position in advance for cold start for use on single and multiple cylinderdiesel engine with PF pump, as claimed in claim 1, where in the said lubricating oil from the said lubricating oil supply pump flows through a plate valve isata pressure of 2.5 - 3 bar. 3. A Roller Ta ppet device for warm start and adaptable for variation of plunger position in advance for cold start for use on single and multiple cylinder diesel engine with PF pump, as claimed in claim 1, wherein the said lubricating oil flows through the said plate valve, lifts the piston by 1.5mm and enables the plunger to be 1.5 mm in advance position for a temperature range between -2S° C to +40° C . 4. A Roller Tappet device for warm start and adaptable for variation of plunger position in advance for cold start for use on single and multiple cylinder diesel engine with PF pump, as claimed in claim 1, wherein the size of the said throttle hole on the said plate valve, is relative to the selected diameter of the said plunger and the peak injection pressure of the pump. 5. A Roller Ta ppet device for warm start and adaptable for variation of plunger position in advance for cold start for use on single and multiple cylinder diesel engine with PF pump, as claimed in claim 1, wherein the said piston moves up and down in the Roller Tappet against plunger spring force and thereby lifts the plunger due to the lubricating oil pressure.

Documents:

600-mas-2001-abstract.pdf

600-mas-2001-claims.pdf

600-mas-2001-correspondence others.pdf

600-mas-2001-correspondence po.pdf

600-mas-2001-description complete.pdf

600-mas-2001-description provisinol.pdf

600-mas-2001-form 1.pdf

600-mas-2001-form 26.pdf

600-mas-2001-form 4.pdf

600-mas-2001-form 5.pdf